MASTER CYLINDER FOR VEHICLE
[Technical Field]
5 [0001]
The present invention relates to a master cylinder for a vehicle.
Priority is claimed on Japanese Patent Application No. 2014-093101, filed April
28, 2014, the content of which is incorporated herein by reference.
[Background Art]
10 [0002]
A master cylinder having a structure in which a covering member configured to
cover an opening side of a cylinder is attached to the cylinder by using a locking member
locked to the opening of the cylinder in order to restrict a piston from coming out via the
covering member (for example, see Patent Literature 1) is known.
15 [Citation List]
[Patent Literature]
[0003]
[Patent Literature 1]
Japanese Unexamined Utility Model Application, First Publication No.
20 S58-54362
[Summary of Invention]
[Technical Problem]
[0004]
In the above-mentioned master cylinder, manufacture thereof is time-consuming.
25 [0005]
2
2
An aspect of the present invention provides a master cylinder for a vehicle
capable of improving manufacturing efficiency.
[Solution to Problem]
[0006]
5 According to a first aspect of the present invention, a master cylinder for a
vehicle includes a piston moved by operation of an operating member; and a cylinder in
which the piston is movably disposed, wherein a movement restriction member disposed
in a radial hole formed in the cylinder and configured to restrict movement of the piston
with respect to the cylinder is disposed at the cylinder, and the movement restriction
10 member fixes a detection member configured to detect the operation of the operating
member to the cylinder.
[0007]
According to a second aspect of the present invention, the cylinder is integrally
formed with a cylinder main body member together with a support section configured to
15 attach the operating member and a reservoir in which a brake fluid is stored, and the
movement restriction member is a screw member configured to fix the detection member
to the cylinder main body member.
[0008]
According to a third aspect of the present invention, the screw member has a
20 distal end side capable of abutting the piston and is configured to restrict movement of
the piston.
[0009]
According to a fourth aspect of the present invention, the movement restriction
member is disposed in the cylinder and restricts movement of the piston via a piston
25 abutting member configured to abut the piston.
3
3
[0010]
According to a fifth aspect of the present invention, the piston abutting member
is a circumferential member extending in a circumferential direction of the cylinder, one
end side of the piston abutting member abuts the piston, and an inclined portion
extending 5 toward the other end side of the piston abutting member and inward in a radial
direction is formed at the portion pressed with the movement restriction member.
[0011]
According to a sixth aspect of the present invention, the piston abutting member
holds the other side of a flexible protection member configured to cover the opening side
10 of the cylinder while having the one side of the piston abutting member being held by the
piston.
[Advantageous Effects of Invention]
[0012]
According to the above-mentioned master cylinder for a vehicle, manufacturing
15 efficiency is improved.
[Brief Description of Drawings]
[0013]
Fig. 1 is a plan view showing a first embodiment according to the present
invention.
20 Fig. 2 is a front view showing a first embodiment according to the present
invention.
Fig. 3 is a side view showing a first embodiment according to the present
invention.
Fig. 4 is a cross-sectional view taken along line X-X of Fig. 3 showing the first
25 embodiment according to the present invention.
4
4
Fig. 5 is an enlarged cross-sectional view of a major part of Fig. 4 showing the
first embodiment according to the present invention.
Fig. 6 is an enlarged cross-sectional view of a major part corresponding to Fig. 5
showing a second embodiment according to the present invention.
Fig. 5 7 is an enlarged cross-sectional view of a major part corresponding to Fig. 5
showing a third embodiment according to the present invention.
Fig. 8 is an enlarged cross-sectional view of a major part corresponding to Fig. 5
showing a fourth embodiment according to the present invention.
[Description of Embodiments]
10 [0014]
[First Embodiment]
A first embodiment according to the present invention will be described with
reference to Figs. 1 to 5. As shown in Figs. 1 to 3, the first embodiment is a
reservoir-integrated master cylinder 11 for a vehicle having a reservoir 10 that composes
15 a part of the master cylinder 11 for a vehicle. The master cylinder 11 for a vehicle is a
member used for a saddle riding vehicle such as a motorcycle, a three-wheeled buggy, a
four-wheeled buggy, and the like, and attached to the vehicle in a state in which the
cylinder is exposed to the outside. Here, a state in which the master cylinder 11 for a
vehicle including the reservoir 10 is attached to a vehicle will be described, and here, a
20 front side of a vehicle is referred to as “front,” a rear side of the vehicle is referred to as
“rear,” a left side of the vehicle is referred to as “left,” and a right side of the vehicle is
referred to as “right.” The first embodiment is a master cylinder 11 for a vehicle
configured to brake a front wheel manipulated by a right hand of a driver. The present
invention may also be applied to a master cylinder configured to brake a rear wheel or a
25 master cylinder for a clutch, which is manipulated by a left hand of a driver. In this case,
5
5
in the following description, left and right sides are reversed.
[0015]
The master cylinder 11 for a vehicle is attached to a mounting section 16 of a
steering bar 15 shown by a two-dot chain line in Fig. 1 of the vehicle. The mounting
5 section 16 is a portion disposed at a right section of the steering bar 15 and extending in
leftward and rightward directions. The steering bar 15 is formed by appropriately
bending a cylindrical pipe member, and an outer circumferential surface of the mounting
section 16 to which at least the master cylinder 11 for a vehicle is attached has a
cylindrical surface shape.
10 [0016]
The master cylinder 11 for a vehicle has a main body member 20 and a holder
21, which are shown in Fig. 1, two mounting bolts 22 and 22, a brake lever 23 (an
operating member), a support bolt 24, a support nut 25 and a lid member 26, which are
shown in Figs. 2 and 3, and two attachment screws 27 and 27 shown in Fig. 1, all of
15 which are formed of a metal. In addition, the master cylinder 11 for a vehicle has a
brake switch 29 (a detection member) having a case 28 formed of a synthetic resin and
shown in Figs. 2 and 3, an attachment screw member 30 (a movement restriction
member), a locking washer 31 and a spring washer 32, all of which are formed of a metal,
and a diaphragm 33 formed of an elastic material such as a rubber and the like and shown
20 in Fig. 4. Here, the brake switch 29 is disposed such that a contact point in the brake
switch 29 is turned on or off by operation of the brake lever 23 to switch on a brake lamp
(not shown) of the vehicle. Further, in the embodiment, while the case 28 of the brake
switch 29 is formed of a synthetic resin, the case 28 may be formed of a metal or a
rubber.
25 [0017]
6
6
The main body member 20 is integrally formed by casting, and as shown in Fig.
1, disposed in front of the mounting section 16 of the steering bar 15. A mounting seat
section 34 is formed at a right portion of the main body member 20 to protrude rearward.
The main body member 20 is attached to the steering bar 15 with the mounting section
5 16 of the steering bar 15 sandwiched between the mounting seat section 34 and the
holder 21. The mounting seat section 34 and the holder 21 are coupled by the two
mounting bolts 22 and 22, which are disposed above and below shown in Figs. 2 and 3,
to sandwich the steering bar 15 therebetween.
[0018]
10 The main body member 20 has a pair of upper and lower plate-shaped lever
support portions 35 and 35 formed at a lower portion of the right portion and protruding
forward as shown in Fig. 3. The brake lever 23 is inserted between the lever support
portions 35 and 35. In this state, the support bolt 24 is threadedly engaged with the
support nut 25 while being inserted through one of the lever support portions 35, the
15 brake lever 23 and the other lever support portion 35 in upward and downward directions.
Accordingly, the brake lever 23 is rotatably supported by the lever support portions 35
and 35, the support bolt 24 and the support nut 25. Here, the brake lever 23 is rotated
about the support bolt 24. As shown in Fig. 1, the brake lever 23 is disposed in front of
the steering bar 15 and extends rightward from the main body member 20 along the
20 steering bar 15. A mirror mounting section 36, to which a rearview mirror (not shown)
is attached further above the lever support portion 35 of the upper side shown in Fig. 3,
i.e., at an upper portion of the right portion shown in Fig. 2, is form at the main body
member 20.
[0019]
25 A cylinder 37 extending leftward from a base end side of the lever support
7
7
portions 35 and 35 is formed at the main body member 20. The cylinder 37 is disposed
in an axial direction of the mounting section 16 in front of the steering bar 15 shown in
Fig. 1. As shown in Fig. 4, the cylinder 37 is formed at a lower portion of the main
body member 20. A reservoir wall section 38 is formed at an upper portion of the main
body member 5 er 20, i.e., above the cylinder 37. The reservoir wall section 38 has a
tubular shape in the upward and downward directions and forms a storage chamber 40
configured to store a brake fluid therein together with a reservoir bottom section 39
configured to close the cylinder 37 side. The reservoir bottom section 39 also composes
an upper portion of the cylinder 37.
10 [0020]
The cylinder 37 is formed in a bottomed cylindrical shape having a cylinder tube
section 45 extending in the leftward and rightward directions, and a cylinder bottom
section 46 disposed at a side of the cylinder tube section 45 opposite to the lever support
portions 35 and 35. In the cylinder 37, a cylinder hole 47 having an opening 48 at the
15 lever support portions 35 and 35 side is formed inside the cylinder tube section 45 and
the cylinder bottom section 46.
[0021]
The cylinder hole 47 is formed in an axial direction of the mounting section 16
of the steering bar 15 shown in Fig. 1. As shown in Fig. 4, the cylinder hole 47 has a
20 main hole section 51 at the cylinder bottom section 46 side, a tapered hole section 52 at a
side of the main hole section 51 opposite to the cylinder bottom section 46, and a lip hole
section 53 at a side of the tapered hole section 52 opposite to the main hole section 51.
An end portion of the lip hole section 53 opposite to the main hole section 51 composes
the opening 48 of the cylinder 37. Central axes of the main hole section 51, the tapered
25 hole section 52 and the lip hole section 53 coincide with each other, and the central axes
8
8
become a central axis of the cylinder hole 47. The central axis of the cylinder hole 47 is
a central axis of the cylinder 37. Hereinafter, the central axis is referred to as a cylinder
axis, a direction along the central axis is referred to as a cylinder axial direction, a
direction perpendicular to the central axis of the cylinder 37 is referred to as a cylinder
5 radial direction, and a direction around the central axis of the cylinder 37 is referred to as
a cylinder circumferential direction.
[0022]
As shown in Fig. 5, in the cylinder hole 47, the main hole section 51 has an
inner circumferential surface 51a having a cylindrical surface shape. The tapered hole
10 section 52 has a diameter-increased inner circumferential surface 52a having a tapered
shape and extending from an edge section of the opening 48 side of the inner
circumferential surface 51a toward the opening 48 with a diameter increased, and a
diameter-increased inner circumferential surface 52b having a tapered shape and
extending from an edge section of the diameter-increased inner circumferential surface
15 52a opposite to the inner circumferential surface 51a toward the opening 48 with a
diameter increased. In the tapered hole section 52, a tapered amount obtained by
subtracting a difference between diameters of both ends in the cylinder axial direction
from a distance between the both ends in the cylinder axial direction is larger at the
diameter-increased inner circumferential surface 52b than the diameter-increased inner
20 circumferential surface 52a.
[0023]
The lip hole section 53 has an inner circumferential surface 53a having a
cylindrical surface shape, a diameter-decreased inner circumferential surface 53b
extending from an edge section of the inner circumferential surface 53a opposite to the
25 opening 48 toward an opposite side of the opening 48 with a diameter decreased, and a
9
9
bottom surface 53c extending inward in the cylinder radial direction from an inner
circumferential edge portion of the diameter-decreased inner circumferential surface 53b.
An inner circumferential edge portion of the bottom surface 53c continues to a
side of the diameter-increased inner circumferential surface 52b of the tapered hole
section 52 opposite to the diameter-increased inner circumferential 5 ential surface 52a. The
bottom surface 53c is parallel to a surface perpendicular to the cylinder axis.
[0024]
As shown in Fig. 4, the main hole section 51 has a larger length in the cylinder
axial direction than that of the lip hole section 53, and a largest length in the cylinder
10 axial direction in the cylinder hole 47. The main hole section 51 has a smaller inner
diameter than that of the lip hole section 53, and a smallest diameter in the cylinder radial
direction in the cylinder hole 47. The lip hole section 53 is disposed at the most
opposite side of the cylinder bottom section 46 in the cylinder hole 47.
[0025]
15 An attachment seat 54 to which the brake switch 29 is attached is formed at the
cylinder tube section 45 at an outer lower portion in the vicinity of a boundary between
the main hole section 51 and the lip hole section 53. The attachment seat 54 has a main
seat portion 55 at the main hole section 51 side in the cylinder axial direction, and a
protrusion seat portion 56 at the lip hole section 53 side in the cylinder axial direction
20 protruding downward further than the main seat portion 55. A wall portion 57 of the
main seat portion 55 side of the protrusion seat portion 56 is parallel to a surface
perpendicular to the cylinder axis. The attachment seat 54 has a stepped shape.
[0026]
Then, a radial hole 58 parallel to the cylinder radial direction is formed in the
25 cylinder tube section 45 at a position of the protrusion seat portion 56 of the attachment
10
10
seat 54. The radial hole 58 is a screw hole, and formed upward from a lower surface of
the protrusion seat portion 56 to be perpendicular to the lower surface. The radial hole
58 is opened at the inner circumferential surface 53a of the lip hole section 53.
[0027]
A 5 screw hole section 59 is formed to pass through the cylinder bottom section
46. While not shown, a bolt configured to attach a port of a brake pipeline to the
cylinder 37 is threadedly engaged with the screw hole section 59. A passage configured
to bring the inside of the main hole section 51 and the brake pipeline in communication
with each other is formed in the bolt. The brake pipeline comes in communication with
10 a wheel cylinder of the brake apparatus such as a disc brake and the like disposed at a
wheel side. A restriction convex section 61 protruding toward an opposite side of the
cylinder tube section 45 and configured to restrict rotation of the port of the brake
pipeline is formed in the cylinder bottom section 46.
[0028]
15 A first communication hole 62 configured to bring the inside of the main hole
section 51 and the storage chamber 40 in communication with each other is formed in the
reservoir bottom section 39 to be parallel to the cylinder radial direction. The first
communication hole 62 is a stepped hole having a diameter that is gradually reduced
from the storage chamber 40 side toward the main hole section 51 side. In addition, a
20 second communication hole (not shown) is also formed in the reservoir bottom section
39 to be closer to the cylinder bottom section 46 than the first communication hole 62.
[0029]
The reservoir wall section 38 is composed by a sidewall section 65 disposed at
the cylinder bottom section 46 side, i.e., the left side, a front wall section 66 disposed at
25 the front side, a sidewall section 67 disposed at an opposite side of the cylinder bottom
11
11
section 46, i.e., the right side, and a rear wall section 68 disposed at the rear side and
shown in Fig. 2. That is, the reservoir wall section 38 has a quadrangular pipe shape.
The reservoir wall section 38 is formed to surround the storage chamber 40 shown in Fig.
4 using the sidewall section 65, the front wall section 66 and the sidewall section 67
5 shown in Fig. 4, and the rear wall section 68 shown in Fig. 2, and an upper portion
thereof is opened.
[0030]
The diaphragm 33 has a frame-shaped plate portion 69 having a quadrangular
frame shape and placed on an upper surface of the reservoir wall section 38, an outer
10 cylindrical portion 70 having a tubular shape and extending downward from an inner
circumferential edge section of the frame-shaped plate portion 69, a lower plate portion
71 having a frame shape and extending inward from a lower edge portion of the outer
cylindrical portion 70, an intermediate cylindrical portion 72 having a tubular shape and
extending upward from an inner circumferential edge portion of the lower plate portion
15 71, and an upper plate portion 73 extending inward from an upper edge section of the
intermediate cylindrical portion 72. The outer cylindrical portion 70, the lower plate
portion 71, the intermediate cylindrical portion 72 and the upper plate portion 73 are
disposed in the storage chamber 40. The diaphragm 33 divides the storage chamber 40
into a liquid chamber 74 disposed below the diaphragm 33 and in which a brake fluid is
20 stored, and an air chamber 75 disposed above the diaphragm 33 and in communication
with the atmosphere. The diaphragm 33 is able to follow a variation of a liquid amount
of the brake fluid in the liquid chamber 74 as the diaphragm 33 is deformed.
[0031]
The lid member 26 is integrally formed by casting and configured to cover the
25 diaphragm 33 from above. The lid member 26 sandwiches the frame-shaped plate
12
12
portion 69 of the diaphragm 33 between a lower surface of the lid member 26 and an
upper surface of the reservoir wall section 38. In this state, the lid member 26 is fixed
to the reservoir wall section 38 shown in Fig. 4 by the attachment screws 27 and 27
shown in Fig. 1. In this way, the diaphragm 33 is directly sandwiched between the
reservoir wall section 38 of the main body member 20 and the lid member 5 26.
[0032]
The master cylinder 11 for a vehicle has a return spring 76, a piston 77, a cup
seal 78, a cup seal 79 and a boot 80. All of these are disposed in the above-mentioned
cylinder hole 47. The boot 80 is composed by a boot main body 81 and a rigid ring 82.
10 The return spring 76, the piston 77 and the rigid ring 82 are formed of a metal, and the
cup seal 78, the cup seal 79 and the boot main body 81 are formed of an elastic material
such as a rubber and the like.
[0033]
The piston 77 has a columnar shaft portion 85, a disc-shaped flange portion 86,
15 a columnar shaft portion 87, a disc-shaped flange portion 88, a columnar shaft portion 89,
a disc-shaped flange portion 90, a columnar shaft portion 91, a disc-shaped flange
portion 92, a columnar shaft portion 93, a columnar shaft portion 94 and a disc-shaped
flange portion 95, and these have a common central axis and are formed coaxially with
each other.
20 [0034]
The shaft portion 85 is formed closest to the cylinder bottom section 46 in the
piston 77, i.e., the left side. The flange portion 86 is disposed at a side of the shaft
portion 85 opposite to the cylinder bottom section 46, i.e., the right side. The flange
portion 86 has an outer diameter larger than that of the shaft portion 85. The shaft
25 portion 87 is disposed at a side of the flange portion 86 opposite to the shaft portion 85.
13
13
The shaft portion 87 has an outer diameter smaller than that of the shaft portion 85. The
flange portion 88 is disposed at a side of the shaft portion 87 opposite to the flange
portion 86. The flange portion 88 has an outer diameter larger than that of the flange
portion 86.
5 [0035]
The shaft portion 89 is disposed at a side of the flange portion 88 opposite to the
shaft portion 87. The shaft portion 89 has an outer diameter smaller than that of the
flange portion 88. The flange portion 90 is disposed at a side of the shaft portion 89
opposite to the flange portion 88. The flange portion 90 has the same outer diameter as
10 that of the flange portion 88. The shaft portion 91 is disposed at a side of the flange
portion 90 opposite to the shaft portion 89. The shaft portion 91 has an outer diameter
smaller than that of the flange portion 90.
[0036]
The flange portion 92 is disposed at a side of the shaft portion 91 opposite to the
15 flange portion 90. The flange portion 92 has the same outer diameter as that of the
flange portion 90. The shaft portion 93 is disposed at a side of the flange portion 92
opposite to the shaft portion 91. The shaft portion 93 has an outer diameter smaller than
that of the flange portion 92. The shaft portion 94 is disposed at a side of the shaft
portion 93 opposite to the flange portion 92. The shaft portion 94 has an outer diameter
20 smaller than that of the shaft portion 93.
[0037]
The flange portion 95 is disposed at a side of the shaft portion 94 opposite to the
shaft portion 93. The flange portion 95 has an outer diameter larger than that of the
shaft portion 94, and the same outer diameter as that of the shaft portion 93. The flange
25 portion 95 is formed at a side of the piston 77 most opposite to the cylinder bottom
14
14
section 46. The piston 77 is slidably fitted into the inner circumferential surface 51a of
the main hole section 51 of the cylinder hole 47 in the flange portions 88, 90 and 92.
Accordingly, the piston 77 is slidably disposed in the cylinder 37 to move in the cylinder
axial direction.
5 [0038]
The return spring 76 is a tapered coil spring, in which one end side in the
cylinder axial direction has a diameter larger than that of the other side, and the return
spring 76 abuts cylinder bottom section 46 at an end portion of the large diameter side
and abuts the flange portion 86 at an end portion of the small diameter side while
10 inserting the shaft portion 85 of the piston 77 inside thereof.
[0039]
The cup seal 78 has a C shape in which one side shape of a cross section in a
surface including a central axis is opened at one side in the cylinder axial direction. The
cup seal 78 is disposed between the flange portions 86 and 88 of the piston 77 to be fitted
15 into the shaft portion 87. The cup seal 78 is in a state in which the C-shaped opening
side is disposed at the flange portion 86 side, and the outer circumferential section comes
in sliding contact with the inner circumferential surface 51a of the main hole section 51.
[0040]
The cup seal 79 has a C shape in which one side shape of a cross section in a
20 surface including a central axis is opened at one side in the cylinder axial direction. The
cup seal 79 is disposed between the flange portions 90 and 92 of the piston 77 to be fitted
into the shaft portion 91. The cup seal 79 is in a state in which the C-shaped opening
side is disposed at the flange portion 90 side, and the outer circumferential section comes
in sliding contact with the inner circumferential surface 51a of the main hole section 51.
25 [0041]
15
15
As shown in Fig. 5, the attachment screw member 30 has a disc-shaped head
section 105, a pillar-shaped screw shaft portion 106 having a diameter smaller than that
of the head section 105 and extending from the head section 105, and a columnar distal
end shaft portion 107 extending from a side of the screw shaft portion 106 opposite to the
head 5 section 105. The head section 105, the screw shaft portion 106 and the distal end
shaft portion 107 are formed coaxially with each other. The distal end shaft portion 107
has an outer circumferential surface 107a having a cylindrical surface shape, a
diameter-decreased outer circumferential surface 107b extending from an edge section of
the outer circumferential surface 107a opposite to the screw shaft portion 106 with a
10 diameter decreased, and a flat distal end surface 107c perpendicular to the central axis.
The C-shaped spring washer 32 and the annular locking washer 31 are inserted through
the distal end shaft portion 107 and the screw shaft portion 106 to be previously attached
to the attachment screw member 30. As the locking washer 31 is locked to the
attachment screw member 30, the locking washer is restricted from coming out of the
15 attachment screw member 30 of the spring washer 32.
[0042]
The case 28 of the brake switch 29 has a main section 110 and an attachment
section 111 having a thickness smaller than that of the main section 110. A wall portion
112 is formed at the attachment section 111 side of the main section 110 of the case 28 in
20 the upward and downward direction and the forward and rearward direction. A
through-hole 113 is formed to pass through the attachment section 111 in a thickness
direction. In the brake switch 29, the main section 110 abuts the main seat portion 55 of
the attachment seat 54, the attachment section 111 abuts the protrusion seat portion 56,
and the wall portion 112 abuts the wall portion 57.
25 [0043]
16
16
In this state, the screw shaft portion 106 is threadedly engaged with the radial
hole 58 serving as a screw hole of the cylinder tube section 45 by inserting the distal end
shaft portion 107 and the screw shaft portion 106 of the attachment screw member 30, to
which the locking washer 31 and the spring washer 32 are previously attached, through
the through-hole 113 of the brake switch 29. As the attachment 5 nt screw member 30 is
disposed in the radial hole 58 while being threadedly engaged with the radial hole 58, the
head section 105 of the attachment screw member 30 sandwiches the spring washer 32,
the locking washer 31 and the attachment section 111 of the brake switch 29 between the
head section 105 and the protrusion seat portion 56 of the cylinder tube section 45, and
10 the brake switch 29 is fixed to the cylinder 37.
[0044]
The attachment screw member 30 in a state in which the brake switch 29 is fixed
to the cylinder 37 has a length such that the distal end shaft portion 107 protrudes inward
in the cylinder radial direction further than the flange portion 92 of the piston 77. In a
15 state in which the flange portion 92 of the piston 77 is disposed at an opposite side of the
opening 48 further than the distal end shaft portion 107 of the attachment screw member
30, the brake switch 29 is fixed to the cylinder 37. Then, even when the piston 77 is
pressed by the return spring 76 shown in Fig. 4 to be moved in a direction coming out of
the cylinder hole 47, the attachment screw member 30 abuts the flange portion 92 of the
20 piston 77 as shown in Fig. 5, and movement of the piston 77 is restricted.
[0045]
That is, the attachment screw member 30 is disposed in the radial hole 58
formed in the cylinder 37 to restrict movement of the piston 77 with respect to the
cylinder 37. Here, the flange portion 92 has an outer circumferential surface 92a having
25 a cylindrical surface shape and serving as a maximum outer diameter section, a
17
17
diameter-decreased outer circumferential surface 92b extending from an edge section of
the shaft portion 93 side of the outer circumferential surface 92a toward the shaft portion
93 side with a diameter decreased, and an end surface 92c extending inward from the
diameter-decreased outer circumferential surface 92b in the cylinder radial direction.
The end surface 92c is parallel to a surface 5 rface perpendicular to the cylinder axis. The
attachment screw member 30 abuts the diameter-decreased outer circumferential surface
92b of the flange portion 92 at the inclined diameter-decreased outer circumferential
surface 107b of the distal end shaft portion 107. Here, as the length of the distal end
shaft portion 107 is increased, the outer circumferential surface 107a having the
10 cylindrical surface shape of the distal end shaft portion 107 may abut the end surface 92c
of the flange portion 92.
[0046]
The brake switch 29 is pressed by the brake lever 23 to become an OFF state in
a state in which the brake lever 23 is not manipulated and become an ON state when the
15 brake lever 23 is manipulated and the brake lever 23 is separated, thereby detecting
operation of the brake lever 23.
[0047]
The boot main body 81 of the boot 80 is formed in a tubular shape, and has a
fitting portion 115 of one end, an intermediate flexible portion 116, and a fitting portion
20 117 of the other end. The fitting portion 115 and the fitting portion 117 are formed in
an annular shape. The flexible portion 116 is formed in a tubular shape having a
thickness in the cylinder radial direction smaller than that of the fitting portion 115 and
the fitting portion 117, and has flexibility. A mounting groove 118 is formed inside in
the cylinder radial direction of the fitting portion 117 of the boot main body 81, and the
25 rigid ring 82 is mounted on the mounting groove 118.
18
18
[0048]
In the boot 80, the fitting portion 115 of the one end of the boot main body 81 is
disposed between the shaft portion 93 and the flange portion 95 of the piston 77 to be
fitted into the shaft portion 94. In addition, the boot 80 is turned outward in the cylinder
radial 5 direction to extend toward the flange portion 92 side in the lip hole section 53 after
the flexible portion 116 extending from the outer circumferential side of the fitting
portion 115 extends toward an opposite side of the flange portion 92 once. In addition,
the boot 80 comes in contact with the inner circumferential surface 53a of the lip hole
section 53 in a state in which deformation in the cylinder radial direction of the fitting
10 portion 117 of the other end is suppressed by the rigid ring 82. Accordingly, the boot 80
covers and protects the opening 48 side of the cylinder 37 while the fitting portion 115 of
one side is held at the piston 77.
[0049]
When the return spring 76, the piston 77, the cup seals 78 and 79 and the boot
15 80 shown in Fig. 4 are assembled to the cylinder hole 47, the cup seals 78 and 79 and the
boot 80 are previously assembled to the piston 77. That is, the cup seal 78 is fitted into
a groove portion composed by the flange portion 86, the shaft portion 87 and the flange
portion 88 of the piston 77. In addition, the cup seal 79 is fitted into a groove portion
composed by the flange portion 90, the shaft portion 91 and the flange portion 92 of the
20 piston 77. In addition, the boot 80 in a state in which the rigid ring 82 is previously
mounted on the boot main body 81 is attached to the piston 77. Here, after the fitting
portion 115 is fitted into a groove portion composed by the shaft portion 93, the shaft
portion 94 and the flange portion 95 of the piston 77 shown in Fig. 5, the flexible portion
116 is made in a state in which the flexible portion 116 extends from the fitting portion
25 115 toward an opposite side of the flange portion 92 and is turned back outward in the
19
19
cylinder radial direction to extend toward the flange portion 92 side.
[0050]
Then, the return spring 76 shown in Fig. 4 is inserted into the cylinder hole 47,
and the piston 77 in the above-mentioned state is inserted into the cylinder hole 47.
Here, 5 the fitting portion 117 shown in Fig. 5 of the boot 80 is also fitted into the lip hole
section 53 of the cylinder hole 47. However, an end surface 117a of the fitting portion
117 opposite to the fitting portion 115 is disposed closer to the opening 48 than the radial
hole 58. In this state, the brake switch 29 is disposed at the attachment seat 54, and in a
state in which the piston 77 is pushed by a predetermined amount such that the flange
10 portion 92 is disposed at an opposite side of the opening 48 farther than the radial hole 58
in order to shrink the return spring 76, the screw shaft portion 106 of the attachment
screw member 30 is engaged with the radial hole 58.
[0051]
Accordingly, the attachment screw member 30 fixes the brake switch 29 to the
15 cylinder 37. Along with this, the attachment screw member 30 is configured such that
the distal end surface 107c of the distal end shaft portion 107 is disposed inside in the
cylinder radial direction further than the outer circumferential surface 92a of the flange
portion 92. Accordingly, as the attachment screw member 30 abuts the flange portion
92 of the piston 77, movement of the piston 77 in a direction of coming out of the
20 cylinder hole 47 is restricted. In this state, the piston 77 disposed in the cylinder 37 is
movable in the cylinder axial direction from a position at which movement thereof is
restricted by the attachment screw member 30 in a direction opposite to the opening 48.
[0052]
After that, the fitting portion 117 of the boot 80 is pushed to a predetermined
25 position by a jig. Accordingly, in the boot 80, the fitting portion 115 of one side is held
20
20
at the piston 77, the fitting portion 117 of the other end abuts the inner circumferential
surface 53a of the lip hole section 53 throughout the circumference thereof, and thus, the
opening 48 side of the cylinder 37 is covered. A position at which the flange portion 92
abuts the attachment screw member 30 is a standby position of the piston 77 in a state in
which 5 the brake lever 23 is not manipulated.
[0053]
The cylinder hole 47 is filled with a brake fluid closer to the cylinder bottom
section 46 shown in Fig. 4 than the cup seal 79 of the piston 77. In addition, the cup
seal 78 forms a fluid pressure chamber 120 in communication with a wheel cylinder (not
10 shown) at the piston 77, the cylinder tube section 45 and the cylinder bottom section 46.
[0054]
A pressing section 125 of the brake lever 23 is disposed at a side of the piston 77
opposite to the cylinder bottom section 46 of the flange portion 95. When the brake
lever 23 is manipulated, the pressing section 125 is moved toward the cylinder bottom
15 section 46 side, i.e., the left side, and the piston 77 is pressed in this direction. Then,
when the piston 77 and the cup seal 78 are integrally moved in a direction of
sandwiching the fluid pressure chamber 120 therebetween and the cup seal 78 passes
over a second communication hole (not shown), communication between the fluid
pressure chamber 120 and the storage chamber 40 is blocked, and a brake fluid is
20 supplied from the fluid pressure chamber 120 to a wheel cylinder (not shown).
[0055]
That is, the master cylinder 11 for a vehicle generates a brake fluid pressure as
the piston 77 is moved in a direction of the cylinder bottom section 46 by operation of
the brake lever 23. Here, a space between the cup seal 78 and the cup seal 79 comes in
25 communication with the storage chamber 40 via the first communication hole 62. In
21
21
addition, when operation of the brake lever 23 is released, as the piston 77 is turned back
by a biasing force of the return spring 76, the brake fluid of the wheel cylinder (not
shown) is turned back into the fluid pressure chamber 120. Here, a capacity of the fluid
pressure chamber of the wheel cylinder side is increased when an amount of a brake
friction material of the brake apparatus is reduced. In the master cylinder 5 r 11 for a
vehicle, when the brake lever 23 is not manipulated, since the fluid pressure chamber 120
comes in communication with the storage chamber 40 via the second communication
hole (not shown), a brake fluid is supplied from the storage chamber 40 into the fluid
pressure chamber 120.
10 [0056]
The reservoir wall section 38 and the reservoir bottom section 39 of the main
body member 20, the lid member 26, the diaphragm 33 and the attachment screws 27 and
27 are formed at an upper portion of the cylinder 37 to configure the reservoir 10 in
which the brake fluid is stored. Accordingly, the reservoir 10 is integrally connected to
15 the master cylinder 11 for a vehicle configured to supply the brake fluid into the wheel
cylinder.
[0057]
The master cylinder disclosed in Patent Literature 1 is attached to the cylinder
by a locking member configured to lock the covering member that covers the opening of
20 the cylinder to the opening of the cylinder, and coming-out of the piston is restricted via
the covering member. For this reason, the locking member is necessary, and the locking
groove configured to lock the locking member should be formed in the inner
circumferential surface of the opening of the cylinder. Accordingly, manufacture such
as cutting of the locking groove, insertion of the locking member, and the like, is
25 complicated, and manufacture thereof is time-consuming. In addition, part cost and
22
22
assembly cost are increased because the number of parts is increased, and machining cost
for forming the locking groove is increased.
[0058]
On the other hand, the above-mentioned master cylinder 11 for a vehicle forms
the radial hole 58 opened in the cylinder hole 47 in the cylinder 5 er 37. In addition, the
attachment screw member 30 configured to fix the brake switch 29 that detects operation
of the brake lever 23 to the cylinder 37 is disposed in the radial hole 58. Then,
movement of the piston 77 in a direction of coming out of the cylinder 37 is restricted by
the attachment screw member 30. In this way, since movement of the piston 77 in the
10 coming-out direction is restricted by the attachment screw member 30 configured to fix
the brake switch 29 to the cylinder 37 to stop the piston 77 at the standby position; an
increase in the number of parts can be suppressed. Accordingly, manufacturing
efficiency of the master cylinder for a vehicle can be improved. In addition, an increase
in part cost and assembly cost can be suppressed. Further, since the radial hole 58
15 opened in the cylinder hole 47 preferably has a depth required for attachment of the
attachment screw member 30, an increase in working cost, machining precision
management cost and machining cost can also be suppressed.
[0059]
[Second embodiment]
20 Next, a second embodiment will be described mainly with reference to Fig. 6
focusing on differences from the first embodiment. Further, the common parts as the
first embodiment are designated by the same names and the same reference numerals.
[0060]
In a master cylinder 11A for a vehicle of the second embodiment, an attachment
25 screw member 30A having a configuration partially different from the attachment screw
23
23
member 30 (see Fig. 5) of the first embodiment is used. The attachment screw member
30A specifically does not have the distal end shaft portion 107 and has a screw shaft
portion 106A partially different from the screw shaft portion 106 of the first embodiment.
The screw shaft portion 106A has a diameter-decreased outer circumferential surface
106Aa having 5 a diameter decreased toward the distal end side and a distal end surface
106Ab perpendicular a central axis of the screw shaft portion 106A which are formed at a
distal end portion opposite to the head section 105. In addition, in the second
embodiment, a metal piston abutting member 130A (a circumferential member) disposed
in the cylinder hole 47 of the cylinder 37 and abutting the flange portion 92 of the piston
10 77 is provided. The piston abutting member 130A is formed by, for example, cutting.
[0061]
The piston abutting member 130A is formed in an annular shape. In the piston
abutting member 130A, an inner circumferential surface 130Aa has a cylindrical surface
shape and an outer circumferential surface 130Ab has a cylindrical surface shape. In
15 the piston abutting member 130A, an end surface 130Ac and an end surface 130Ad of
both sides in the cylinder axial direction are flat surfaces parallel to a surface
perpendicular to the cylinder axis. The piston abutting member 130A is inserted into
the lip hole section 53 while inserting the piston 77 inside thereof. In this state, the
piston abutting member 130A has an annular shape extending in the cylinder
20 circumferential direction. In the piston abutting member 130A, a smallest diameter of
the end surfaces 130Ac and 130Ad is smaller than a largest diameter of the end surface
92c of the flange portion 92 of the piston 77.
[0062]
In the second embodiment, when the cup seal 78 (see Fig. 4), the cup seal 79
25 and the boot 80 are previously assembled to the piston 77, the piston abutting member
24
24
130A is also assembled. That is, the piston abutting member 130A is attached to the
piston 77 as the shaft portions 93 and 94 and the flange portion 95 are inserted into the
piston abutting member 130A at the inner side. After that, the fitting portion 115 of the
boot 80 in a state in which the rigid ring 82 is previously mounted on the boot main body
81 is fitted into the groove 5 ve portion composed by the shaft portion 93, the shaft portion 94
and the flange portion 95 of the piston 77.
[0063]
Then, the flexible portion 116 extends from the fitting portion 115 toward an
opposite side of the flange portion 92 and then is turned back outward in the cylinder
10 radial direction to extend toward the flange portion 92 side, and the piston abutting
member 130A is sandwiched between the fitting portion 117 and the flange portion 92.
Here, the end surface 130Ac of the one side of the piston abutting member 130A abuts
the end surface 92c of the flange portion 92, and the end surface 130Ad of the other side
abuts the end surface 117a of the fitting portion 117 opposite to the fitting portion 115.
15 Accordingly, the piston abutting member 130A is temporarily assembled to the piston 77.
[0064]
Then, the return spring 76 (see Fig. 4) is inserted into the cylinder hole 47, and
the piston 77 in which the cup seal 78 (see Fig. 4), the cup seal 79, the boot 80 and the
piston abutting member 130A are previously assembled is inserted into the cylinder hole
20 47. Next, the piston 77 and the fitting portion 117 of the boot 80 are pushed to a
predetermined amount by a jig, and these are positioned with respect to the lip hole
section 53 in the cylinder axial direction.
[0065]
At this time, a boundary corner portion between the end surface 130Ac and the
25 outer circumferential surface 130Ab of the piston abutting member 130A may be
25
25
positioned to abut the diameter-decreased inner circumferential surface 53b of the lip
hole section 53. In addition, a diameter-decreased outer circumferential surface having
a diameter which becomes smaller as it comes closer to the end surface 130Ac side may
be formed at the boundary between the end surface 130Ac and the outer circumferential
surface 130Ab of the piston abutting member 130A, and the positioning 5 may be
performed by abutting the diameter-decreased outer circumferential surface to the
diameter-decreased inner circumferential surface 53b of the lip hole section 53. Further,
the positioning may be performed by abutting the end surface 130Ac to the bottom
surface 53c of the lip hole section 53 while avoiding a contact with the
10 diameter-decreased inner circumferential surface 53b of the lip hole section 53 at the
diameter-decreased outer circumferential surface.
[0066]
In a state in which the piston 77 and the piston abutting member 130A are
positioned with respect to the lip hole section 53 in the cylinder axial direction, the brake
15 switch 29 is disposed at the attachment seat 54, and the screw shaft portion 106A of the
attachment screw member 30A is threadedly engaged with the radial hole 58.
Accordingly, the attachment screw member 30A fixes the brake switch 29 to the cylinder
37. Along with this, in the attachment screw member 30A, the distal end surface 106Ab
of the screw shaft portion 106A abuts the outer circumferential surface 130Ab of the
20 piston abutting member 130A, and the other portion than the outer circumferential
surface 130Ab is pressed against the inner circumferential surface 53a of the lip hole
section 53. As a result, the piston abutting member 130A is fixed to the cylinder 37.
[0067]
The piston abutting member 130A fixed to the cylinder 37 by the attachment
25 screw member 30A in this way restricts movement of the piston 77 in the direction
26
26
coming out of the cylinder hole 47 as the end surface 92c of the flange portion 92 abuts
the end surface 130Ac throughout the circumference thereof. A position at which the
flange portion 92 abuts the piston abutting member 130A is a standby position of the
piston 77 in a state in which the brake lever 23 is not manipulated.
5 [0068]
Here, the piston abutting member 130A may not be formed in an annular shape
but may be, for example, a C-shaped member, a portion of an annular shape of which is
cut out, as long as the member extends in the circumferential direction of the cylinder 37.
[0069]
10 According to the above-mentioned second embodiment, the attachment screw
member 30A restricts movement of the piston 77 via the piston abutting member 130A
disposed in the cylinder 37 and abutting the piston 77. For this reason, in comparison
with the case in which the movement is restricted by the direct abutting by the
attachment screw member 30, an area of a portion abutting the piston 77 when the
15 movement is restricted can be easily increased. That is, since the piston abutting
member 130A has a shape extending in the circumferential direction of the cylinder 37,
the area of the portion abutting the piston 77 when the movement is restricted can be
increased. Accordingly, scratches of the piston 77 can be suppressed.
[0070]
20 [Third embodiment]
Next, a third embodiment will be described mainly with reference to Fig. 7
focusing on differences from the first and second embodiments. Further, the common
parts as the first and second embodiments are designated by the same names and the
same reference numerals.
25 [0071]
27
27
In a master cylinder 11B for a vehicle of the third embodiment, a main body
member 20B having a configuration partially different from the main body member 20
(see Figs. 5 and 6) of the first and second embodiments is used. A radial hole 58B in
which a forming position with respect to the radial hole 58 of first and second
embodiments 5 s in the cylinder axial direction is deviated toward the opening 48 is formed
in the main body member 20B. Accordingly, the main body member 20B has a cylinder
37B, a cylinder tube section 45B, a cylinder hole 47B, an attachment seat 54B, a
protrusion seat portion 56B, a lip hole section 53B and an inner circumferential surface
53Ba, in which the radial hole 58B disposed at a position different from the radial hole
10 58 is formed, corresponding to the cylinder 37, the cylinder tube section 45, the cylinder
hole 47, the attachment seat 54, the protrusion seat portion 56, the lip hole section 53 and
the inner circumferential surface 53a of the first and second embodiments.
[0072]
In the third embodiment, according to the above-mentioned description, a brake
15 switch 29B having a configuration different from the brake switch 29 (see Figs. 5 and 6)
of the first and second embodiments is used. That is, a through-hole 113B having a
forming position deviated from the through-hole 113 of the first and second embodiments
is formed in the brake switch 29B. Accordingly, the brake switch 29B has a case 28B
and an attachment section 111B, in which the through-hole 113B disposed at a position
20 different from the through-hole 113 is formed, corresponding to the case 28 and the
attachment section 111 of the first and second embodiments.
[0073]
In the third embodiment, an attachment screw member 30B having a
configuration different from the attachment screw member 30A (see Fig. 6) of the second
25 embodiment is used. Specifically, a screw shaft portion 106B having a length slightly
28
28
larger than that of the screw shaft portion 106A of the second embodiment is formed at
the attachment screw member 30B. The screw shaft portion 106B has a
diameter-decreased outer circumferential surface 106Ba having a length larger than that
of the diameter-decreased outer circumferential surface 106Aa of the second embodiment,
and a distal end surface 106Bb having a diameter 5 smaller than that of the distal end
surface 106Ab of the second embodiment.
[0074]
In the third embodiment, a piston abutting member 130B having a configuration
partially different from the piston abutting member 130A (see Fig. 6) of the second
10 embodiment is used. Specifically, the piston abutting member 130B has a thickness in
the cylinder axial direction smaller than that of the piston abutting member 130A of the
second embodiment, and an inclined portion 131B having an inclined surface 130Be with
a diameter decreased toward the distal end side in the cylinder axial direction is formed
at the outer circumferential section of the one side in the cylinder axial direction.
15 Accordingly, the piston abutting member 130B has an inner circumferential surface
130Ba and an outer circumferential surface 130Bb having a width in the cylinder axial
direction smaller than that of the inner circumferential surface 130Aa and the outer
circumferential surface 130Ab of the second embodiment, an end surface 130Bc having
the same shape as the end surface 130Ac of the first embodiment, and an end surface
20 130Bd having a width in the cylinder radial direction smaller than that of the end surface
130Ad of the first embodiment. In the piston abutting member 130B, at least a smallest
diameter of the end surface 130Bc is smaller than a largest diameter of the end surface
92c of the flange portion 92 of the piston 77.
[0075]
25 In the third embodiment, like the second embodiment, the cup seal 78 (see Fig.
29
29
4), the cup seal 79, the boot 80 and the piston abutting member 130B are previously
assembled to the piston 77. Here, the piston abutting member 130B is assembled such
that the inclined surface 130Be and the end surface 130Bd are directed toward a side of
the piston 77 opposite to the flange portion 92.
5 [0076]
Then, the piston 77 in a state in which the return spring 76 (see Fig. 4) is
inserted into the cylinder hole 47B, and the cup seal 78 (see Fig. 4), the cup seal 79, the
boot 80 and the piston abutting member 130B are previously assembled is inserted into
the cylinder hole 47B. Then, the piston 77 and the fitting portion 117 of the boot 80 is
10 pushed to a predetermined amount by a jig, and the piston abutting member 130B is
positioned at a predetermined position in the radial hole 58B which is opposite to the
opening 48.
[0077]
At this time, a boundary corner portion between the end surface 130Bc and the
15 outer circumferential surface 130Bb of the piston abutting member 130B may be
positioned to abut the diameter-decreased inner circumferential surface 53b of the lip
hole section 53B. In addition, a diameter-decreased outer circumferential surface
having a diameter which becomes smaller as it comes closer to the end surface 130Bc
side may be formed at the boundary between the end surface 130Bc and the outer
20 circumferential surface 130Bb of the piston abutting member 130B, and the positioning
may be performed by abutting the diameter-decreased outer circumferential surface to the
diameter-decreased inner circumferential surface 53b of the lip hole section 53B.
Further, the positioning may be performed by abutting the end surface 130Bc to the
bottom surface 53c of the lip hole section 53B while avoiding a contact of the lip hole
25 section 53B with the diameter-decreased inner circumferential surface 53b at the
30
30
diameter-decreased outer circumferential surface.
[0078]
In a state in which the piston 77 and the piston abutting member 130B are
positioned with respect to the lip hole section 53B in the cylinder axial direction, the
brake 5 switch 29B is disposed at the attachment seat 54B, the screw shaft portion 106B of
the attachment screw member 30B is threadedly engaged with the radial hole 58B, and
the brake switch 29B is fixed to the cylinder 37B.
[0079]
Then, the diameter-decreased outer circumferential surface 106Ba of the
10 attachment screw member 30B becomes adjacent with respect to the inclined surface
130Be of the inclined portion 131B of the piston abutting member 130B at the opening
48 side while having the positions in the cylinder axial direction overlapping with each
other. Accordingly, the attachment screw member 30B restricts further movement of
the piston abutting member 130B in a direction coming out of the cylinder 37B as the
15 diameter-decreased outer circumferential surface 106Ba abuts the inclined surface 130Be
of the piston abutting member 130B.
[0080]
Then, the piston abutting member 130B in a state in which movement in the
direction coming out of the cylinder 37B at the attachment screw member 30B is
20 restricted in this way restricts movement of the piston 77 in the direction coming out of
the cylinder hole 47B as the end surface 92c of the flange portion 92 abuts the end
surface 130Bc throughout the circumference. A position at which the flange portion 92
abuts the piston abutting member 130B abutting the attachment screw member 30B is a
standby position of the piston 77 in a state in which the brake lever 23 is not manipulated.
25 When the screw shaft portion 106B of the attachment screw member 30B is threadedly
31
31
engaged with the radial hole 58B, the diameter-decreased outer circumferential surface
106Ba of the attachment screw member 30B presses and moves the fitting portion 117 of
the boot 80 toward the opening 48 side.
[0081]
5 Here, upon fixing of the brake switch 29B, the inclined surface 130Be of the
inclined portion 131B of the piston abutting member 130B may be pressed by the
diameter-decreased outer circumferential surface 106Ba of the attachment screw member
30B. Then, a boundary corner portion between the end surface 130Bc and the outer
circumferential surface 130Bb of the piston abutting member 130B is pushed to the
10 diameter-decreased inner circumferential surface 53b of the lip hole section 53B by the
pressing, and the outer circumferential surface 130Bb may be pushed to the inner
circumferential surface 53Ba of the lip hole section 53B. As a result, when the
attachment screw member 30B fixes the brake switch 29B to the cylinder 37B, the piston
abutting member 130B is also positioned with respect to the cylinder 37B to be
15 immovably fixed.
[0082]
In this case, a diameter-decreased outer circumferential surface having a
diameter decreased toward the end surface 130Bc side may be formed at the boundary
between the end surface 130Bc and the outer circumferential surface 130Bb of the piston
20 abutting member 130B, and the diameter-decreased outer circumferential surface may be
positioned and fixed to abut the diameter-decreased inner circumferential surface 53b of
the lip hole section 53B. Further, the end surface 130Bc may be positioned and fixed to
abut the bottom surface 53c of the lip hole section 53B while avoiding a contact with the
diameter-decreased inner circumferential surface 53b of the lip hole section 53B at the
25 diameter-decreased outer circumferential surface.
32
32
[0083]
The piston abutting member 130B may not be formed in an annular shape but
may be, for example, a C-shaped member, a portion of an annular shape of which is cut
out, as long as the member extends in the circumferential direction of the cylinder 37B.
5 [0084]
According to the above-mentioned third embodiment, the inclined portion 131B
having the inclined surface 130Be extending toward the other end side of the piston
abutting member 130B and inward in the cylinder radial direction is formed at a portion
abutting the attachment screw member 30B while the piston abutting member 130B
10 extends in the cylinder circumferential direction and one end side of the piston abutting
member 130B abuts the piston 77. Accordingly, the attachment screw member 30B
overlaps the piston abutting member 130B in the cylinder radial direction. Accordingly,
the piston abutting member 130B can be suppressed from moving over the attachment
screw member 30B even when few relaxations occur in the attachment screw member
15 30B.
[0085]
In addition, the piston abutting member 130B has the inclined portion 131B.
For this reason, even when the piston abutting member 130B overlaps the attachment
screw member 30B in the cylinder radial direction, an overlapping length of the piston
20 abutting member 130B and the attachment screw member 30B in the cylinder axial
direction can be increased. Accordingly, elongation and magnification in the axial
direction of the cylinder 37B can be suppressed. In addition, the piston abutting
member 130B can be positioned to restrict movement in the cylinder axial direction.
[0086]
25 [Fourth embodiment]
33
33
Next, a fourth embodiment will be described mainly with reference to Fig. 8
focusing on differences from the first to third embodiments. Further, the common parts
as the first to third embodiments are designated by the same names and the same
reference numerals.
5 [0087]
In a master cylinder 11C for a vehicle of the fourth embodiment, the main body
member 20B, the brake switch 29B and the attachment screw member 30B having the
same configurations as the third embodiment are used.
[0088]
10 In the fourth embodiment, a boot 80C having a configuration partially different
from the boot 80 (see Figs. 5 to 7) of the first to third embodiments is used. The boot
80C has a boot main body 81C (a flexible protection member) having a configuration
partially different from the boot main body 81 of the first to third embodiments. Like
the boot main body 81, the boot main body 81C is configured to cover and protect the
15 opening 48 side of the cylinder 37B, and has a flexible portion 116C longer than the
flexible portion 116 of the first to third embodiments, and a fitting portion 117C different
from the fitting portion 117 of the first to third embodiments. The fitting portion 117C
has annular outer protrusion portions 151C and 152C disposed parallel with each other in
the cylinder axial direction and protruding outward in the cylinder radial direction, and
20 an annular inner protrusion portion 153C protruding inward in the cylinder radial
direction at a position in the cylinder axial direction matched to the outer protrusion
portion 151C opposite to the flexible portion 116. Then, the boot 80C has a piston
abutting member 130C attached to the fitting portion 117C.
[0089]
25 Since the piston abutting member 130C is formed by bending a metal plate, the
34
34
piston abutting member 130C is formed in an annular shape having an inner tube portion
161C, a curved tube portion 162C, an end plate portion 163C, a curved tube portion
164C, an outer tube portion 165C and a tapered tube portion 166C (an inclined portion).
The inner tube portion 161C is formed in a cylindrical shape. The curved tube portion
162C extends to be curved to have a diameter which becomes 5 s larger as it gets outward
from an edge portion of one side in the cylinder axial direction of the inner tube portion
161C to the outside in the cylinder axial direction. The end plate portion 163C extends
outward in the cylinder radial direction from an edge section of a large diameter side of
the curved tube portion 162C and has a flat plate shape parallel to a surface perpendicular
10 to the central axis of the inner tube portion 161C. The curved plate portion 164C
extends to be curved to be disposed at the same side as the inner tube portion 161C in the
cylinder axial direction as it gets outward from the outer circumferential edge section of
the end plate portion 163C. The outer tube portion 165C is formed in a cylindrical
shape, and extends from an edge portion of the curved plate portion 164C opposite to the
15 end plate portion 163C in a direction away from the end plate portion 163C. The
tapered tube portion 166C extends from an edge portion of the outer tube portion 165C
opposite to the curved tube portion 164C in a direction away from the end plate portion
163C, and has a diameter decreased toward the extended distal end side.
[0090]
20 An annular fitting groove 167C is formed in the piston abutting member 130C
inside the inner tube portion 161C, the curved tube portion 162C, the end plate portion
163C, the curved tube portion 164C, the outer tube portion 165C and the tapered tube
portion 166C. The fitting groove 167C is opened at the outside between the inner tube
portion 161C and the tapered tube portion 166C.
25 [0091]
35
35
Then, the fitting portion 117C of the boot main body 81C is fitted into the fitting
groove 167C via an opening between the inner tube portion 161C and the tapered tube
portion 166C. Here, the fitting portion 117C causes the inner protrusion portion 153C
to abut the inner tube portion 161C and the curved tube portion 162C, causes the outer
5 protrusion portion 151C to abut the curved tube portion 164C and the outer tube portion
165C, and causes the outer protrusion portion 152C to abut the outer tube portion 165C
and the tapered tube portion 166C. Accordingly, the piston abutting member 130C is
held at the fitting portion 117C of the other end of the boot main body 81C in which the
fitting portion 115 of the one side is held at the piston 77. The piston abutting member
10 130C is inserted into the lip hole section 53B while the piston 77 is inserted through the
inside of the inner tube portion 161C. The piston abutting member 130C is formed in
an annular shape in the cylinder circumferential direction in this state.
[0092]
An inner circumferential surface 161Ca of the inner tube portion 161C is formed
15 in a cylindrical surface shape, and an outer circumferential surface 165Ca of the outer
tube portion 165C is also formed in a cylindrical surface shape. An end surface 163Ca
outside in the cylinder axial direction of the end plate portion 163C of the one side in the
cylinder axial direction is a flat surface parallel to a surface perpendicular to the cylinder
axis. The outside in the cylinder radial direction of the tapered tube portion 166C is a
20 tapered diameter-decreased outer circumferential surface 166Ca extending inward in the
cylinder radial direction with a diameter which becomes smaller as it gets away from the
end surface 163Ca. The inner circumferential surface 161Ca, the end surface 163Ca,
the outer circumferential surface 165Ca and the diameter-decreased outer circumferential
surface 166Ca are formed coaxially with each other. In the piston abutting member
25 130C, a smallest diameter of at least the end surface 163Ca is smaller than a largest
36
36
diameter of the end surface 92c of the flange portion 92 of the piston 77.
[0093]
In the fourth embodiment, like the second embodiment, the cup seal 78 (see Fig.
4), the cup seal 79 and the boot 80C are previously assembled to the piston 77. Here,
the piston abutting member 5 er 130C and the boot main body 81C are in a separated state,
and before the piston abutting member 130C, the tapered tube portion 166C is directed
toward an opposite side of the flange portion 92 to insert the shaft portions 93 and 94 and
the flange portion 95 of the piston 77 into the tapered tube portion 166C, and the boot
80C is disposed at the piston 77. After that, the fitting portion 115 of the boot main
10 body 81C is fitted into a groove portion composed by the shaft portion 93, the shaft
portion 94 and the flange portion 95 of the piston 77.
[0094]
Next, after the flexible portion 116C extends from the fitting portion 115 toward
an opposite side of the flange portion 92, the flexible portion 116C is turned back to the
15 outside in the cylinder radial direction to extend toward the flange portion 92 and fitted
into the fitting groove 167C of the piston abutting member 130C to which the fitting
portion 117C is previously attached.
[0095]
Then, the piston 77 in a state in which the return spring 76 (see Fig. 4) is
20 inserted into the cylinder hole 47B, and the cup seal 78 (see Fig. 4), the cup seal 79 and
the boot 80C including the piston abutting member 130C are previously assembled is
inserted into the cylinder hole 47B. The piston 77 and the piston abutting member
130C are pushed to a predetermined amount by a jig, and the piston abutting member
130C is positioned at a predetermined position in the radial hole 58B which is opposite to
25 the opening 48. Here, the end surface 163Ca of the piston abutting member 130C may
37
37
be positioned to abut the bottom surface 53c of the lip hole section 53B.
[0096]
In a state in which the piston abutting member 130C is positioned with respect
to the lip hole section 53B in the cylinder axial direction, the brake switch 29B is
disposed at the attachment 5 nt seat 54B, the screw shaft portion 106B of the attachment
screw member 30B is threadedly engaged with the radial hole 58B, and the brake switch
29B is fixed to the cylinder 37B.
[0097]
Then, the diameter-decreased outer circumferential surface 106Ba of the
10 attachment screw member 30B becomes adjacent with respect to the diameter-decreased
outer circumferential surface 166Ca of the tapered tube portion 166C of the piston
abutting member 130C at the opening 48 side while having the positions in the cylinder
axial direction overlapping with each other. Accordingly, the attachment screw member
30B restricts movement of the piston abutting member 130C in a direction coming out of
15 the cylinder 37B as the diameter-decreased outer circumferential surface 106Ba abuts the
diameter-decreased outer circumferential surface 166Ca of the tapered tube portion 166C
of the piston abutting member 130C.
[0098]
Then, the piston abutting member 130C in a state in which the movement in the
20 direction coming out of the cylinder 37B is restricted by the attachment screw member
30B restricts movement of the piston 77 in the direction coming out of the cylinder hole
47B as the end surface 92c of the flange portion 92 abuts the end surface 163Ca
throughout the circumference. A position at which the flange portion 92 abuts the
piston abutting member 130C abutting the attachment screw member 30B is a standby
25 position of the piston 77 in a state in which the brake lever 23 is not manipulated.
38
38
[0099]
Here, upon fixing of the brake switch 29B, the diameter-decreased outer
circumferential surface 166Ca of the tapered tube portion 166C of the piston abutting
member 130C may be pressed by the diameter-decreased outer circumferential surface
106Ba of the attachment screw member 30B. Then, 5 due to the pressing, the end surface
163Ca of the piston abutting member 130C may be pressed against the bottom surface
53c of the lip hole section 53B, and the outer circumferential surface 165Ca may be
pressed against the inner circumferential surface 53Ba of the lip hole section 53B. As a
result, when the attachment screw member 30B fixes the brake switch 29B to the
10 cylinder 37B, the piston abutting member 130C is also positioned with respect to the
cylinder 37B to be immovably fixed.
[0100]
The piston abutting member 130C may also not be formed in an annular shape
but may be, for example, a C-shaped member, a portion of an annular shape of which is
15 cut out, as long as the member extends in the circumferential direction of the cylinder
37B. In addition, the portion having a diameter increased from the tapered tube portion
166C in a direction opposite to the end plate portion 163C may be formed at the piston
abutting member 130C, and the end portion inside the cylinder of the boot main body
may be fitted onto the outer circumferential side of the portion.
20 [0101]
According to the above-mentioned fourth embodiment, one side of the piston
abutting member 130C is held by the piston 77 to hold the other side of the boot main
body 81C configured to cover the opening 48 side of the cylinder 37B. For this reason,
as the piston abutting member 130C is attached to the cylinder 37B by the attachment
25 screw member 30B, the other side of the boot main body 81C can be attached to the
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cylinder 37B. Accordingly, the opening 48 side of the cylinder 37B can be
appropriately protected by the boot main body 81C.
In addition, since the piston abutting member 130C having stiffness holds a
shape of the other side of the boot main body 81C, a rigid ring is unnecessary.
5 [0102]
According to the above-mentioned embodiment, in the master cylinder for a
vehicle having a piston moved by operation of the operating member and a cylinder in
which the piston is movable, the movement restriction member disposed in the radial
hole formed in the cylinder and configured to restrict movement of the piston is disposed
10 at the cylinder, and the movement restriction member fixes the detection member
configured to detect the operation of the operating member to the cylinder.
Accordingly, since movement of the piston is restricted by the movement
restriction member configured to fix the detection member to the cylinder, an increase in
the number of parts can be suppressed. Accordingly, manufacturing efficiency of the
15 master cylinder for a vehicle can be improved. In addition, an increase in part cost and
assembly cost can be suppressed. Further, since the radial hole required for attachment
of the movement restriction member is used, an increase in machining cost can be
suppressed.
[0103]
20 The movement restriction member restricts movement of the piston via the
piston abutting member disposed in the cylinder and abutting the piston. Accordingly,
in comparison with the case in which movement of the piston is restricted by direct
abutting the movement restriction member, an area of the abutting portion of the piston
can be easily increased when the movement is restricted. Accordingly, scratches of the
25 piston can be suppressed and reliability of products is improved.
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[0104]
The piston abutting member is a circumferential member (an annular shape, a C
shape is also possible) extending in the circumferential direction of the cylinder, one end
side of the piston abutting member abuts the piston, and the inclined portion extending
toward the other end side of the piston abutting member 5 er and inward in the cylinder radial
direction is formed at the portion pressed with the movement restriction member.
Accordingly, even when the movement restriction member is somewhat deviated in the
radial hole in the coming-out direction, the piston abutting member can be suppressed
from moving over the movement restriction member.
10 [0105]
The piston abutting member holds the other side of the flexible protection
member configured to cover the opening side of the cylinder while having the one side
of the piston abutting member being held by the piston. For this reason, as the piston
abutting member is attached to the cylinder by the movement restriction member, the
15 other side of the flexible protection member can be attached to the cylinder.
Accordingly, the opening side of the cylinder can be appropriately protected by
the flexible protection member.
[Industrial Applicability]
[0106]
20 According to the above-mentioned master cylinder for a vehicle, manufacturing
efficiency is improved.
[Reference Signs List]
[0107]
11, 11A, 11B, 11C Master cylinder for a vehicle
25 23 Brake lever (operating member)
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29, 29B Brake switch (detection member)
30, 30A, 30B Attachment screw member (movement restriction member)
37, 37B Cylinder
48 Opening
5 58, 58B Radial hole
77 Piston
81C Boot main body (flexible protection member)
130A, 130B, 130C Piston abutting member (circumferential member)
131B Inclined portion
10 166C Tapered tube portion (inclined portion)
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[CLAIMS]
[Claim 1]
A master cylinder for a vehicle comprising:
a piston moved by operation of an operating member; and
5 a cylinder in which the piston is movably disposed,
wherein a movement restriction member disposed in a radial hole formed in the
cylinder and configured to restrict movement of the piston with respect to the cylinder is
disposed at the cylinder, and
the movement restriction member fixes a detection member configured to detect
10 the operation of the operating member to the cylinder.
[Claim 2]
The master cylinder for a vehicle according to claim 1, wherein the cylinder is
integrally formed with a cylinder main body member together with a support section
configured to attach the operating member and a reservoir in which a brake fluid is stored,
15 and
the movement restriction member is a screw member configured to fix the
detection member to the cylinder main body member.
[Claim 3]
The master cylinder for a vehicle according to claim 2, wherein the screw
20 member has a distal end side capable of abutting the piston and is configured to restrict
movement of the piston.
[Claim 4]
The master cylinder for a vehicle according to claim 1 or 2, wherein the
movement restriction member is disposed in the cylinder and restricts movement of the
25 piston via a piston abutting member configured to abut the piston.
43
I/We Claim:
43
[Claim 5]
The master cylinder for a vehicle according to claim 4, wherein the piston
abutting member is a circumferential member extending in a circumferential direction of
the cylinder, one end side of the piston abutting member abuts the piston, and an inclined
portion extending toward the other end side of the piston abutting member 5 and inward in
a radial direction is formed at the portion pressed with the movement restriction member.
[Claim 6]
The master cylinder for a vehicle according to claim 4 or 5, wherein the piston
abutting member holds the other side of a flexible protection member configured to cover
10 the opening side of the cylinder while having the one side of the piston abutting member
being held by the piston.