[Technical Field]
[0001]
The present invention relates to a disc brake for braking a vehicle.
5 Priority is claimed on Japanese Patent Application No. 2015-096081, filed May
8, 2015, the content of which is incorporated herein by reference.
[Background Art]
[0002]
A boot which covers a portion protruding from a guide hole of a slide pin is
10 provided in a disc brake. There are cases in which an interposed portion disposed to be
interposed between the slide pin and the guide hole is provided in the boot. In such a
disc brake, a penetrating groove penetrating in an axial direction is formed in the
interposed portion for bleeding air from the guide hole when the slide pin is inserted into
the guide hole (see Patent Literature 1, for example).
15 [Citation List]
[Patent Literature]
[0003]
[Patent Literature 1]
Japanese Unexamined Patent Application, First Publication No. 2006-38164
20 [Summary of Invention]
[Technical Problem]
[0004]
A bellows portion is provided in the boot. When a slide pin is inserted into a
guide hole, if an inner circumferential portion of the bellows portion comes into contact
25 with the slide pin, it causes resistance to relative movement of the slide pin and may
2
decrease workability of assembling work.
[0005]
The present invention provides a disc brake which can minimize decrease in
workability of assembling work.
5 [Solution to Problem]
[0006]
According to one aspect of the present invention, a disc brake includes a carrier
having a pair of pads respectively disposed to face both sides of a disc and fixed to a
vehicle across an outer circumferential side of the disc, a caliper supported on the carrier
10 to be movable in a disc axial direction with a slide pin interposed therebetween and
configured to press the pair of pads against the disc, and a boot provided between the
carrier and the caliper and having an expandable/contractible bellows portion, the boot
into which the slide pin is inserted. The bellows portion includes at least two inwardly
bent portions bent toward a radial inner side, protruding portions protruding from an
15 inner circumferential surface of each of the inwardly bent portions toward an outer
circumferential surface of the slide pin are formed, and passage portions are formed
adjacent to each of the protruding portions when each of the protruding portions comes
into contact with the outer circumferential surface of the slide pin.
[Advantageous Effects of the Invention]
20 [0007]
According to the above-described disc brake, it is possible to minimize decrease
in workability of assembling work.
[Brief Description of Drawings]
[0008]
25 Fig. 1 is a plan view illustrating a disc brake according to an embodiment of the
3
present invention in which a portion thereof is illustrated as a cross-sectional view.
Fig. 2 is a cross-sectional view illustrating a sliding connection portion of the
disc brake according to the embodiment of the present invention.
Fig. 3 is a plan view illustrating a boot of the disc brake according to the
5 embodiment of the present invention.
Fig. 4 is a front view illustrating the boot of the disc brake according to the
embodiment of the present invention.
Fig. 5 is a cross-sectional view taken along line X-X of Fig. 4.
Fig. 6 is a cross-sectional view illustrating the sliding connection portion of the
10 disc brake according to the embodiment of the present invention in the process of
assembly.
Fig. 7 is a longitudinal sectional view illustrating a first modified example of the
boot according to the embodiment of the present invention.
Fig. 8 is a perspective view illustrating a second modified example of the boot
15 according to the embodiment of the present invention.
Fig. 9 is a cross-sectional view illustrating the second modified example of the
boot and a pin according to the embodiment of the present invention.
[Description of Embodiments]
[0009]
20 An embodiment of the present invention will be described below with reference
to the drawings. As illustrated in Fig. 1, a disc brake 10 according to the present
embodiment is for a vehicle such as an automobile, specifically for a four-wheeled
vehicle. The disc brake 10 brakes a vehicle by stopping rotation of a disc 11 rotating
together with wheels (not illustrated). In the following description, a direction of a
25 center axis of the disc 11 will be referred to as a disc axial direction, and a rotating
4
direction of the disc 11 will be described as a disc rotating direction.
[0010]
The disc brake 10 includes a carrier 12, a pair of pads 13, a caliper 15, and a pair
of boots 16. The carrier 12 is disposed across an outer circumferential side of the disc
5 11 and fixed to a non-rotating portion of a vehicle. The pair of pads 13 are supported by
the carrier 12 and disposed to face both surfaces of the disc 11. The caliper 15
sandwiches the pair of pads 13 and presses them against both surfaces of the disc 11.
[0011]
The carrier 12 is constituted by a carrier main body 21 and a pair of pad guides
10 22 attached to the carrier main body 21.
[0012]
The carrier main body 21 is made of a metal such as iron or an aluminum alloy.
The carrier main body 21 is disposed across the outer circumferential side of the disc 11
and attached to a non-rotating portion of a vehicle. In the carrier main body 21, a pair
15 of support portions 25 extending in the disc axial direction are provided on an inlet side
and outlet side in the disc rotating direction. These support portions 25 cross the outer
circumferential side of the disc 11 in the disc axial direction. The pair of pad guides 22
are attached to sides in which these support portions 25 face each other. The carrier
main body 21 supports the inlet side and outlet side in the disc rotating direction of the
20 pair of pads 13 with these pad guides 22 interposed therebetween. In this state of being
supported as above, the pair of pads 13 becomes movable in the disc axial direction with
respect to the carrier 12. In other words, the carrier 12 supports the pair of pads 13 to be
movable in the disc axial direction.
[0013]
25 Guide holes 26 are formed in each of the pair of support portions 25 in the disc
5
axial direction from one end portion in the disc axial direction to a midway position on
the other end side. Therefore, the pair of guide holes 26 are provided in the carrier 12.
The pair of guide holes 26 are non-penetrating holes whose bottom sides are closed.
[0014]
5 The caliper 15 is supported by the carrier 12 to be movable in the disc axial
direction in a state in which the caliper 15 straddles the outer circumferential side of the
disc 11 in the disc axial direction. The caliper 15 includes a caliper main body 31, a
pair of bolts 32, a pair of slide pins 33, and a piston (not illustrated).
[0015]
10 The pair of slide pins 33 are made of a metal such as iron. The pair of slide
pins 33 are attached to the inlet side and outlet side in the disc rotating direction of the
caliper main body 31. One slide pin 33 is slidably fitted into one guide hole 26 formed
in one support portion 25 of the carrier main body 21. The other slide pin 33 is slidably
fitted into the other guide hole 26 formed in the other support portion 25 of the carrier
15 main body 21. Thereby, the caliper main body 31 fixed to the pair of slide pins 33
becomes movable integrally with the pair of slide pins 33 in the disc axial direction. In
other words, the caliper 15 is supported by the carrier 12 to be movable in the disc axial
direction with the pair of slide pins 33 interposed therebetween.
[0016]
20 The caliper main body 31 includes a cylinder portion 41, a bridge portion 42,
and a claw portion 43. The cylinder portion 41 is disposed on one side of the caliper
main body 31 in the disc axial direction. The claw portion 43 is disposed on the other
side in the disc axial direction. The bridge portion 42 connects the cylinder portion 41
to the claw portion 43. The caliper main body 31 is constituted of a metal such as iron
25 or an aluminum alloy and each of the portions described above is formed by casting.
6
[0017]
A fitting hole (not illustrated) for slidably fitting the piston (not illustrated) is
formed in the cylinder portion 41. The fitting hole is formed in the disc axial direction
to open toward the claw portion 43. The piston (not illustrated) and the cylinder portion
5 41 slidably supporting the piston are provided on one side of the caliper 15 in the disc
axial direction. The cylinder portion 41 is disposed on an inner side (an inner side in a
vehicle width direction) with respect to the disc 11.
[0018]
The cylinder portion 41 includes a base portion 52 and a pair of extended
10 portions 53. The base portion 52 includes a fitting hole (not illustrated) into which the
piston (not shown) is fitted, and has a bottomed cylindrical shape. The pair of extended
portions 53 extends from the base portion 52 to the inlet side and outlet side in the disc
rotating direction. Mounting holes 54 penetrating in the disc axial direction are formed
in each of the pair of extended portions 53. Therefore, the caliper main body 31
15 includes the pair of mounting holes 54.
[0019]
The bridge portion 42 extends from the cylinder portion 41 across the outer
circumference of the disc 11 in the disc axial direction. The claw portion 43 is provided
on a side of the bridge portion 42 opposite to the cylinder portion 41 so as to face the
20 cylinder portion 41.
[0020]
One bolt 32 in which one slide pin 33 is inserted into the mounting hole 54 is
mounted on one extended portion 53 of the cylinder portion 41. The other bolt 32 in
which the other slide pin 33 is inserted into the mounting hole 54 is mounted on the other
25 extended portion 53 of the cylinder portion 41. Also, one slide pin 33 is slidably
7
inserted into the guide hole 26 of one support portion 25 of the carrier 12, and the other
slide pin 33 is slidably inserted into the guide hole 26 of the other support portion 25 of
the carrier 12. Thereby, the caliper 15 having the pair of slide pins 33 is slidably
supported in the disc axial direction by the carrier 12 having the pair of support portions
5 25.
[0021]
One of the boots 16 is provided to be extendable and contractible between the
extended portion 53 side of one slide pin 33 of the caliper 15 and one support portion 25
of the carrier 12, and covers the one slide pin 33. The other of the boots 16 is provided
10 to be extendable and contractible between the extended portion 53 side of the other slide
pin 33 of the caliper 15 and the other support portion 25 of the carrier 12, and covers the
other slide pin 33.
[0022]
One extended portion 53, one bolt 32, and one slide pin 33 of the caliper 15, and
15 one support portion 25 and one boot 16 of the carrier 12, which are all disposed on the
inlet side in the disc rotating direction, constitute one sliding connection portion 61.
The carrier 12 and the caliper 15 are slidably connected to each other by the one sliding
connection portion 61. Similarly, the other extended portion 53, the other bolt 32, and
the other slide pin 33 of the caliper 15, and the other support portion 25 and the other
20 boot 16 of the carrier 12, which are all disposed on the outlet side in the disc rotating
direction, constitute the other sliding connection portion 61. The carrier 12 and the
caliper 15 are slidably connected to each other by the other sliding connection portion 61.
Since these sliding connection portions 61 have the same structure, description will be
made in more detail below taking one of the sliding connection portions 61 as an
25 example.
8
[0023]
As illustrated in Fig. 2, the slide pin 33 includes a flange portion 62, an
intermediate shaft portion 63, and a fitting shaft portion 64. The flange portion 62 is
formed at one end portion in the axial direction of the slide pin 33. A cylindrical outer
5 circumferential surface 62a of the flange portion 62 is the largest diameter portion in the
slide pin 33.
[0024]
The intermediate shaft portion 63 is provided adjacent to the flange portion 62.
A maximum outer diameter of the intermediate shaft portion 63 is smaller than the
10 maximum outer diameter of the flange portion 62. An annular fitting groove 65
recessed toward a radial inner side is formed on the flange portion 62 side in the
intermediate shaft portion 63. The intermediate shaft portion 63 includes a
large-diameter outer circumferential surface 63a, a tapered surface 63b, a small-diameter
outer circumferential surface 63c, and a reduced diameter surface 63d. The
15 large-diameter outer circumferential surface 63a has a cylindrical shape. The
large-diameter outer circumferential surface 63a is disposed adjacent to the fitting groove
65 on a side opposite to the flange portion 62. The tapered surface 63b extends toward
a side opposite to the flange portion 62 from an end edge portion of the large-diameter
outer circumferential surface 63a on the side opposite to the flange portion 62 such that a
20 diameter thereof decreases with distance away from the flange portion 62. The
small-diameter outer circumferential surface 63c has a cylindrical shape. The
small-diameter outer circumferential surface 63c extends toward the side opposite to the
flange portion 62 from an end edge portion of the tapered surface 63b on the side
opposite to the flange portion 62. The reduced diameter surface 63d extends toward the
25 side opposite to the flange portion 62 from an end edge portion of the small-diameter
9
outer circumferential surface 63c on the side opposite to the flange portion 62 such that a
diameter thereof decreases with distance away from the flange portion 62. The
small-diameter outer circumferential surface 63c has a smaller diameter compared to the
large-diameter outer circumferential surface 63a.
5 [0025]
The fitting shaft portion 64 has a maximum outer diameter smaller than the
maximum outer diameter of the intermediate shaft portion 63. The fitting shaft portion
64 has a cylindrical outer circumferential surface 64a. The outer circumferential surface
64a extends toward the side opposite to the flange portion 62 from an end edge portion of
10 the reduced diameter surface 63d on the side opposite to the flange portion 62. In the
fitting shaft portion 64, the outer circumferential surface 64a is a portion having the
largest diameter. On the fitting shaft portion 64, a plurality of axial direction grooves 66
are formed at intervals in a circumferential direction at a portion on the side opposite to
the flange portion 62. The axial direction grooves 66 are recessed toward the radial
15 inner side from the outer circumferential surface 64a and extend in the axial direction.
[0026]
In the slide pin 33, a screw hole 67 is formed at a center in the radial direction of
an end portion on the flange portion 62 side in the axial direction. The screw hole 67 is
formed in an area from the flange portion 62 to the intermediate shaft portion 63. The
20 bolt 32 inserted into the mounting hole 54 of the extended portion 53 is screwed into the
screw hole 67, thereby the slide pin 33 being fixed to the extended portion 53. The
slide pin 33 is slidably fitted to a cylindrical inner circumferential surface 26a of the
guide hole 26 of the carrier 12 on the outer circumferential surface 64a of the fitting shaft
portion 64. In the guide hole 26, a tapered surface 26b is formed on an opening side
25 thereof. The tapered surface 26b extends in a tapered shape having a larger diameter
10
toward an end side of the opening from an end edge portion of the inner circumferential
surface 26a on the opening side.
[0027]
The support portion 25 of the carrier 12 includes a support portion main body
5 portion 71 and an annular protruding portion 72 which protrudes from the support
portion main body portion 71 while surrounding the guide hole 26. An annular fitting
groove 73 is formed in the protruding portion 72. The fitting groove 73 is recessed
toward the radial inner side from a cylindrical outer circumferential surface 72a of the
protruding portion 72.
10 [0028]
The boot 16 illustrated in Figs. 3 and 4 is a part made of synthetic rubber. The
boot 16 is a tubular member which is expandable and contractible in the axial direction.
As illustrated in Fig. 2, one end portion of the boot 16 in the axial direction is fitted into
the fitting groove 65 of the slide pin 33. The other end portion of the boot 16 in the
15 axial direction is fitted into the fitting groove 73 of the carrier 12. The boot 16 is
disposed to extend in the disc axial direction between the carrier 12 and the caliper 15.
The boot 16 expands and contracts according to movement of the caliper 15
with respect to the carrier 12.
[0029]
20 As illustrated in Figs. 3 to 5, the boot 16 includes an annular caliper connecting
portion 81 at one end in the axial direction, an annular carrier connecting portion 82 at
the other end in the axial direction, and an expandable/contractible bellows portion 83
therebetween.
[0030]
25 As illustrated in Fig. 5, the caliper connecting portion 81 includes an annular
11
fitting portion 87 formed at one end portion in the axial direction of the boot 16 and a
tubular portion 88 having a substantially cylindrical shape extending from an outer
circumferential edge portion of the fitting portion 87 toward the carrier connecting
portion 82 side. The fitting portion 87 protrudes toward the radial inner side from the
5 tubular portion 88. On an inner circumferential side of the tubular portion 88, a
plurality of protrusions 89 protruding toward the radial inner side from an inner
circumferential surface 88a thereof are formed at intervals in the circumferential
direction. As illustrated in Fig. 2, the caliper connecting portion 81 is fitted into the
fitting groove 65 of the slide pin 33 at the fitting portion 87.
10 [0031]
As illustrated in Fig. 5, the carrier connecting portion 82 includes an annular
fitting portion 91 formed at the other end portion in the axial direction of the boot 16 and
a tubular portion 92 having a substantially cylindrical shape extending from an outer
circumferential edge portion of the fitting portion 91 toward the caliper connecting
15 portion 81. The fitting portion 91 protrudes toward the radial inner side from the
tubular portion 92. The carrier connecting portion 82 includes an annular inwardly
extending portion 93 extending from an end edge portion of the tubular portion 92 on the
side of the caliper connecting portion 81 toward the radial inner side and a tubular lip
portion 94 protruding from an inner circumferential end portion of the inwardly
20 extending portion 93 toward a side opposite to the caliper connecting portion 81. In the
present embodiment, the lip portion 94 is configured as an interposed portion.
[0032]
An inner circumferential surface 82a of the carrier connecting portion 82 on the
side of the caliper connecting portion 81 has a tapered shape in which a diameter thereof
25 increases toward the caliper connecting portion 81. An inner circumferential surface
12
82b of the carrier connecting portion 82 on the side opposite to the caliper connecting
portion 81 has a cylindrical shape. In the carrier connecting portion 82, a plurality of
axial direction grooves 95 recessed toward a radial outer side from the inner
circumferential surfaces 82a and 82b and extending in the axial direction are formed at
5 intervals in the circumferential direction as illustrated in Fig. 3. As illustrated in Fig. 5,
the axial direction grooves 95 penetrate along the inner circumferential surface 82b in the
axial direction. The axial direction grooves 95 also penetrate along the inner
circumferential surface 82a in the axial direction. An outer circumferential surface 94a
of the lip portion 94 has a tapered shape in which a diameter thereof decreases toward the
10 side opposite to the caliper connecting portion 81.
[0033]
As illustrated in Fig. 2, the carrier connecting portion 82 is fitted into the fitting
groove 73 of the carrier 12 at the fitting portion 91 and covers the protruding portion 72
at the tubular portion 92, the inwardly extending portion 93, and the lip portion 94. At
15 that time, the lip portion 94 enters the guide hole 26 and its outer circumferential surface
94a is brought into close contact with the tapered surface 26b of the guide hole 26.
[0034]
As illustrated in Fig. 5, the bellows portion 83 includes a first tapered tubular
portion 101, a second tapered tubular portion 102, a third tapered tubular portion 103, a
20 fourth tapered tubular portion 104, and a fifth tapered tubular portion 105.
[0035]
The first tapered tubular portion 101 extends in a tapered tubular shape from an
end edge portion on the carrier connecting portion 82 side of the tubular portion 88 of the
caliper connecting portion 81 to have a larger diameter toward the carrier connecting
25 portion 82. The second tapered tubular portion 102 extends in a tapered tubular shape
13
from an end edge portion on the carrier connecting portion 82 side of the first tapered
tubular portion 101 to have a smaller diameter toward the carrier connecting portion 82.
The third tapered tubular portion 103 extends in a tapered tubular shape from an edge
portion on the carrier connecting portion 82 side of the second tapered tubular portion
5 102 to have a larger diameter toward the carrier connecting portion 82. The fourth
tapered tubular portion 104 extends in a tapered tubular shape from an end edge portion
on the carrier connecting portion 82 side of the third tapered tubular portion 103 to have
a smaller diameter toward the carrier connecting portion 82. The fifth tapered tubular
portion 105 extends in a tapered tubular shape from an end edge portion on the carrier
10 connecting portion 82 side of the fourth tapered tubular portion 104 to have a larger
diameter toward the carrier connecting portion 82. An end edge of the fifth tapered
tubular portion 105 on the side of the carrier connecting portion 82 is connected to a
boundary position between the tubular portion 92 and the inwardly extending portion 93
of the carrier connecting portion 82. That is, the bellows portion 83 is formed by
15 connecting a plurality of tapered tubular portions 101 to 105 in which a taper direction is
alternately reversed from one side to the other side in the disc axial direction of the
caliper 15.
[0036]
In the bellows portion 83, respective radial widths of the first tapered tubular
20 portion 101, the third tapered tubular portion 103, and the fifth tapered tubular portion
105 which increase in diameter toward the carrier connecting portion 82 side are equal to
each other. In the bellows portion 83, respective radial widths of the second tapered
tubular portion 102 and the fourth tapered tubular portion 104 which decrease in
diameter toward the carrier connecting portion 82 side are equal to each other. The
25 respective radial widths of the second tapered tubular portion 102 and the fourth tapered
14
tubular portion 104 are wider than the respective radial widths of the first tapered tubular
portion 101, the third tapered tubular portion 103, and the fifth tapered tubular portion
105.
[0037]
5 In the bellows portion 83, an inner circumferential portion of a boundary portion
between the first tapered tubular portion 101 and the caliper connecting portion 81 is a
first small-diameter inner circumferential portion 111 (a small-diameter inner
circumferential portion) which is smaller in diameter than an inner circumferential
portion of adjacent portions. An inner circumferential portion of a boundary portion
10 between the first tapered tubular portion 101 and the second tapered tubular portion 102
is a first large-diameter inner circumferential portion 112 (a large-diameter inner
circumferential portion) which is larger in diameter than an inner circumferential portion
of adjacent portions. An inner circumferential portion of a boundary portion between
the second tapered tubular portion 102 and the third tapered tubular portion 103 is a
15 second small-diameter inner circumferential portion 113 (a small-diameter inner
circumferential portion in the middle in an extending/contracting direction) which is
smaller in diameter than an inner circumferential portion of adjacent portions. An inner
circumferential portion of a boundary portion between the third tapered tubular portion
103 and the fourth tapered tubular portion 104 is a second large-diameter inner
20 circumferential portion 114 (a large-inner circumferential portion) which is larger in
diameter than an inner circumferential portion of adjacent portions. An inner
circumferential portion of a boundary portion between the fourth tapered tubular portion
104 and the fifth tapered tubular portion 105 is a third small-diameter inner
circumferential portion 115 (a small-diameter inner circumferential portion in the middle
25 in the extending/contracting direction) which is smaller in diameter than an inner
15
circumferential portion of adjacent portions. An inner circumferential portion of a
boundary portion between the fifth tapered tubular portion 105 and the carrier connecting
portion 82 is a third large-diameter inner circumferential portion 116 (a large-diameter
inner circumferential portion) which is larger in diameter than an inner circumferential
5 portion of adjacent portions. Since the second small-diameter inner circumferential
portion 113 and the third small-diameter inner circumferential portion 115 are bent
toward the radial inner side, they are also referred to as inwardly bent portions. In other
words, the bellows portion 83 includes at least two inwardly bent portions.
[0038]
10 Therefore, the first small-diameter inner circumferential portion 111 is formed at
one end portion in the axial direction of the bellows portion 83, that is, in the
expanding/contracting direction thereof. The third large-diameter inner circumferential
portion 116 is formed at the other end portion in the extending/contracting direction of
the bellows portion 83. The first large-diameter inner circumferential portion 112, the
15 second small-diameter inner circumferential portion 113, the second large-diameter inner
circumferential portion 114, and the third small-diameter inner circumferential portion
115 are provided in the middle in the expanding/contracting direction of the bellows
portion 83. As described above, in the bellows portion 83, the small-diameter inner
circumferential portion 111, the large-diameter inner circumferential portion 112, the
20 small-diameter inner circumferential portion 113, the large-diameter inner
circumferential portion 114, the small-diameter inner circumferential portion 115, and the
large-diameter inner circumferential portion 116 are arranged in that order from one side
of the caliper 15 to the other side in the disc axial direction, that is, from the caliper
connecting portion 81 toward the carrier connecting portion 82. Therefore, the
25 small-diameter inner circumferential portions and the large-diameter inner
16
circumferential portions are alternately disposed in the bellows portion 83. In the
bellows portion 83, the first small-diameter inner circumferential portion 111 at one end
in the extending/contracting direction is smaller in diameter than the third large-diameter
inner circumferential portion 116 at the other end.
5 [0039]
The second small-diameter inner circumferential portion 113 includes an annular
main body portion 121 and protruding portions 122 having a protruding shape protruding
toward the radial inner side from an inner circumferential surface 121a which is a
minimum diameter portion of the main body portion 121. A plurality of protruding
10 portions 122 are formed on the second small-diameter inner circumferential portion 113
at intervals in the circumferential direction thereof.
Therefore, the second small-diameter inner circumferential portion 113 serves as
passage portions 123 in which portions between the protruding portions 122 adjacent to
each other in the circumferential direction are recessed toward the radial outer side from
15 distal end surfaces 122a of the adjacent protruding portions 122. A plurality of such
passage portions 123 are formed at intervals in the circumferential direction. A width of
the protruding portion 122 in the circumferential direction of the second small-diameter
inner circumferential portion 113 is smaller than the interval between adjacent protruding
portions 122.
20 [0040]
The third small-diameter inner circumferential portion 115 includes an annular
main body portion 126 and protruding portions 127 having a protruding shape protruding
toward the radial inner side from an inner circumferential surface 126a of the main body
portion 126 on the caliper connecting portion 81 side. The inner circumferential surface
25 126a has a larger diameter toward the caliper connecting portion 81 in the axial direction.
17
A plurality of protruding portions 127 are formed on the third small-diameter inner
circumferential portion 115 at intervals in the circumferential direction.
Therefore, the third small-diameter inner circumferential portion 115 serves as
passage portions 128 in which portions between the protruding portions 127 adjacent to
5 each other in the circumferential direction are recessed toward the radial outer side from
distal end surfaces 127a of the adjacent protruding portions 127. A plurality of such
passage portions 128 are formed at intervals in the circumferential direction. A width of
the protruding portion 127 in the circumferential direction of the third small-diameter
inner circumferential portion 115 is smaller than the interval between adjacent protruding
10 portions 127. As described above, the protruding portions 122 and 127 protruding from
the inner circumferential surface of the inwardly bent portions toward the outer
circumferential surface of the slide pin 33 are formed in the bellows portion 83.
[0041]
In the bellows portion 83, an outer circumferential portion of the boundary
15 portion between the first tapered tubular portion 101 and the caliper connecting portion
81 is a first small-diameter outer circumferential portion 131 which is smaller in diameter
than an outer circumferential portion of adjacent portions. An outer circumferential
portion of the boundary portion between the first tapered tubular portion 101 and the
second tapered tubular portion 102 is a first large-diameter outer circumferential portion
20 132 (an outer bent portion) which is larger in diameter than an outer circumferential
portion of adjacent portions. An outer circumferential portion of the boundary portion
between the second tapered tubular portion 102 and the third tapered tubular portion 103
is a second small-diameter outer circumferential portion 133 which is smaller in diameter
than an outer circumferential portion of adjacent portions. An outer circumferential
25 portion of the boundary portion between the third tapered tubular portion 103 and the
18
fourth tapered tubular portion 104 is a second large-diameter outer circumferential
portion 134 (an outer bent portion) which is larger in diameter than an outer
circumferential portion of adjacent portions. An outer circumferential portion of the
boundary portion between the fourth tapered tubular portion 104 and the fifth tapered
5 tubular portion 105 is a third small-diameter outer circumferential portion 135 which is
smaller in diameter than an outer circumferential portion of adjacent portions. An outer
circumferential portion of the boundary portion between the fifth tapered tubular portion
105 and the carrier connecting portion 82 is a third large-diameter outer circumferential
portion 136 which is larger in diameter than an outer circumferential portion of adjacent
10 portions. Since the first large-diameter outer circumferential portion 132 and the second
large-diameter outer circumferential portion 134 are bent toward the radial outer side,
they are also referred to as outwardly bent portions.
[0042]
Therefore, in the bellows portion 83, the first small-diameter outer
15 circumferential portion 131 is formed at one end portion in the axial direction, that is, in
the expanding/contracting direction, and the third large-diameter outer circumferential
portion 136 is formed at the other end portion in the extending/contracting direction.
The first large-diameter outer circumferential portion 132, the second small-diameter
outer circumferential portion 133, the second large-diameter outer circumferential
20 portion 134, and the third small-diameter outer circumferential portion 135 are provided
in the middle in the expanding/contracting direction of the bellows portion 83. As
described above, in the bellows portion 83, the small-diameter outer circumferential
portion 131, the large-diameter outer circumferential portion 132, the small-diameter
outer circumferential portion 133, the large-diameter outer circumferential portion 134,
25 the small-diameter outer circumferential portion 135, and the large-diameter outer
19
circumferential portion 136 are arranged in that order from one side of the caliper 15 to
the other side in the disc axial direction, that is, from the caliper connecting portion 81
toward the carrier connecting portion 82. Therefore, the small-diameter outer
circumferential portions and the large-diameter outer circumferential portions are
5 alternately disposed in the bellows portion 83.
[0043]
In the bellows portion 83, among the small-diameter inner circumferential
portions 111 and 113 adjacent to each other in the axial direction, the second
small-diameter inner circumferential portion 113 on a side close to a distal end of the
10 slide pin 33 is smaller in diameter than the first small-diameter inner circumferential
portion 111 on a side close to a base end of the slide pin 33. That is, an inner diameter
of an inscribed circle of the distal end surfaces 122a of the plurality of protruding
portions 122, which is a minimum inner diameter of the second small-diameter inner
circumferential portion 113, is smaller than a minimum inner diameter of the first
15 small-diameter inner circumferential portion 111. In addition, a minimum inner
diameter of the inner circumferential surface 121a of the main body portion 121 of the
second small-diameter inner circumferential portion 113 is also smaller than a minimum
inner diameter of the first small-diameter inner circumferential portion 111.
[0044]
20 In the bellows portion 83, among the small-diameter inner circumferential
portions 113 and 115 adjacent to each other in the axial direction, the third
small-diameter inner circumferential portion 115 on the side close to the distal end of the
slide pin 33 is smaller in diameter than the second small-diameter inner circumferential
portion 113 on the side close to the base end of the slide pin 33. That is, an inner
25 diameter of an inscribed circle of the distal end surfaces 127a of the plurality of
20
protruding portions 127, which is a minimum inner diameter of the third small-diameter
inner circumferential portion 115, is smaller than an inner diameter of an inscribed circle
of the distal end surfaces 122a of the plurality of protruding portions 122, which is a
minimum inner diameter of the second small-diameter inner circumferential portion 113.
5 In addition, a minimum inner diameter of the inner circumferential surface 126a of the
main body portion 126 of the third small-diameter inner circumferential portion 115 is
also smaller than a minimum inner diameter of the inner circumferential surface 121a of
the main body portion 121 of the second small-diameter inner circumferential portion
113.
10 [0045]
In the bellows portion 83, among the large-diameter inner circumferential
portions 112 and 114 adjacent to each other in the axial direction, a maximum inner
diameter of the second large-diameter inner circumferential portion 114 on the side close
to the distal end of the slide pin 33 is smaller than a maximum inner diameter of the first
15 large-diameter inner circumferential portion 112 on the side close to the base end of the
slide pin 33. Also, among the large-diameter inner circumferential portions 114 and 116
adjacent to each other in the axial direction, a maximum inner diameter of the third
large-diameter inner circumferential portion 116 on the side close to the distal end of the
slide pin 33 is smaller than a maximum inner diameter of the second large-diameter inner
20 circumferential portion 114 on the side close to the base end of the slide pin 33.
[0046]
In the bellows portion 83, among the small-diameter outer circumferential
portions 133 and 135 adjacent to each other in the axial direction, a minimum outer
diameter of the third small-diameter outer circumferential portion 135 on the side close
25 to the distal end of the slide pin 33 is smaller than a minimum outer diameter of the
21
second small-diameter outer circumferential portion 133 on the side close to the base end
of the slide pin 33. Also, among the small-diameter outer circumferential portions 131
and 133 adjacent to each other in the axial direction, a minimum outer diameter of the
second small-diameter outer circumferential portion 133 on the side close to the distal
5 end of the slide pin 33 is smaller than a minimum outer diameter of the first
small-diameter outer circumferential portion 131 on the side close to the base end of the
slide pin 33.
[0047]
In the bellows portion 83, among the large-diameter outer circumferential
10 portions 134 and 136 adjacent to each other in the axial direction, a maximum outer
diameter of the third large-diameter outer circumferential portion 136 on the side close to
the distal end of the slide pin 33 is smaller than a maximum outer diameter of the second
large-diameter outer circumferential portion 134 on the side close to the base end of the
slide pin 33. Also, among the large-diameter outer circumferential portions 132 and
15 134 adjacent to each other in the axial direction, a maximum outer diameter of the second
large-diameter outer circumferential portion 134 on the side close to the distal end of the
slide pin 33 is smaller than a maximum outer diameter of the first large-diameter outer
circumferential portion 132 on the side close to the base end of the slide pin 33.
[0048]
20 In assembling the caliper 15 to the carrier 12 as illustrated in Fig. 1, the carrier
connecting portion 82 of the boot 16 is first attached to the protruding portion 72
illustrated in Fig. 2 of the carrier 12. That is, the carrier connecting portion 82 is fitted
into the fitting groove 73 of the carrier 12 at the fitting portion 91, and the protruding
portion 72 is covered with the tubular portion 92, the inwardly extending portion 93, and
25 the lip portion 94. At that time, the outer circumferential surface 94a of the lip portion
22
94 is brought into contact with the tapered surface 26b of the guide hole 26.
[0049]
In this state, the slide pin 33 of the caliper 15 is inserted into an inside of the
boot 16 with the fitting shaft portion 64 at the head, and the fitting shaft portion 64 is
5 fitted into the lip portion 94 and the guide hole 26. At this time, air is discharged from
the guide hole 26 according to the extent to which the fitting shaft portion 64 illustrated
in Fig. 6 enters through the axial direction grooves 95 illustrated in Fig. 5 formed on the
inner circumferential side of the inwardly extending portion 93 and the lip portion 94.
A minimum inner diameter of the inscribed circle of the distal end surfaces 122a of the
10 plurality of protruding portions 122 of the second small-diameter inner circumferential
portion 113 of the boot 16 and a minimum inner diameter of the inscribed circle of the
distal end surfaces 127a of the plurality of protruding portions 127 of the third
small-diameter inner circumferential portion 115 are larger than the outer circumferential
surface 64a of the fitting shaft portion 64 of the slide pin 33. Therefore, the fitting shaft
15 portion 64 can enter the inside of the second small-diameter inner circumferential portion
113 and the third small-diameter inner circumferential portion 115 without coming in
contact therewith.
[0050]
The minimum inner diameter of the inscribed circle of the distal end surfaces
20 122a of the plurality of protruding portions 122 of the second small-diameter inner
circumferential portion 113 of the boot 16 is smaller in diameter than the small-diameter
outer circumferential surface 63c of the intermediate shaft portion 63 of the slide pin 33.
Therefore, as the engagement of the fitting shaft portion 64 with the guide hole 26 further
progresses, as illustrated in Fig. 6, the distal end surfaces 122a of the plurality of
25 protruding portions 122 of the second small-diameter inner circumferential portion 113
23
come into contact with the small-diameter outer circumferential surface 63c of the
intermediate shaft portion 63 of the slide pin 33. At that time, although the second
small-diameter inner circumferential portion 113 comes into contact with the slide pin 33
with a tightening margin, the passage portions 123 illustrated in Fig. 5 between the
5 adjacent protruding portions 122 cause a space 141 illustrated in Fig. 6 on the side closer
to the carrier connecting portion 82 than the second small-diameter inner circumferential
portion 113 of the boot 16 to communicate with a space 142 on the side opposite to the
carrier connecting portion 82 of the second small-diameter inner circumferential portion
113 of the boot 16. Therefore, the air discharged from the guide hole 26 to the space
10 141 according to the extent to which the fitting shaft portion 64 enters is smoothly
discharged from the space 141 to the space 142, thereby minimizing the air causing
resistance when fitting the fitting shaft portion 64 into the guide hole 26.
[0051]
Here, among the small-diameter inner circumferential portions 113 and 115
15 illustrated in Fig. 5, the third small-diameter inner circumferential portion 115 on the side
close to the distal end of the slide pin 33 is smaller in diameter than the second
small-diameter inner circumferential portion 113 on the side close to the base end of the
slide pin 33. Among the large-diameter inner circumferential portions 112 and 114, the
maximum inner diameter of the second large-diameter inner circumferential portion 114
20 on the side close to the distal end of the slide pin 33 is smaller than the maximum inner
diameter of the first large-diameter inner circumferential portion 112 on the side close to
the base end of the slide pin 33. Therefore, a ratio of the volume of the space 142 to the
volume of the space 141 illustrated in Fig. 6 is large. Therefore, the volume of the
space 142 serving as a buffer of the air discharged from the space 141 becomes large, and
25 the air from the space 141 can be discharged preferably. Therefore, it is possible to
24
further minimize air causing resistance when fitting the fitting shaft portion 64 into the
guide hole 26.
[0052]
In addition, the second small-diameter inner circumferential portion 113 comes
5 into contact with the small-diameter outer circumferential surface 63c of the intermediate
shaft portion 63 of the slide pin 33 at the distal end surfaces 122a of the plurality of
protruding portions 122. Therefore, contact areas therebetween are reduced and
frictional resistance can also be suppressed.
[0053]
10 Here, unless the plurality of protruding portions 122, that is, the plurality of
passage portions 123 are formed in the second small-diameter inner circumferential
portion 113 illustrated in Fig. 5, the boot 16 comes into contact with the small-diameter
outer circumferential surface 63c of the intermediate shaft portion 63 of the slide pin 33
illustrated in Fig. 6 over the entire circumference on the inner circumferential surface
15 121a of the main body portion 121. Then, communication between the space 141 and
the space 142 is blocked. Then, the air discharged from the guide hole 26 to the space
141 according to the extent to which the fitting shaft portion 64 enters cannot be
discharged from the space 141 to the space 142, and thus a pressure in the space 141 rises
and causes resistance to the discharge of the air from the guide hole 26, which causes
20 resistance when fitting the slide pin 33 into the guide hole 26. In the present
embodiment, it is possible to suppress such resistance when fitting the slide pin 33 into
the guide hole 26.
[0054]
Further, when the small-diameter inner circumferential portions 113 and 115
25 have the same diameter and the large-diameter inner circumferential portions 112 and
25
114 have the same diameter, the ratio of the volume of the space 142 to the volume of the
space 141 cannot be increased and the volume of the space 142 serving as a buffer for the
air discharged from the space 141 does not increase. In the present embodiment, since
the ratio of the volume of the space 142 to the volume of the space 141 can be increased,
5 also from this perspective, resistance when fitting the slide pin 33 into the guide hole 26
can also be suppressed.
[0055]
Further, when the boot 16 comes in contact with the small-diameter outer
circumferential surface 63c of the intermediate shaft portion 63 of the slide pin 33 over
10 the entire circumference on the inner circumferential surface 121a of the main body
portion 121, a contact area increases and frictional resistance increases. In the present
embodiment, such frictional resistance can be suppressed.
[0056]
The minimum inner diameter of the inscribed circle of the distal end surfaces
15 127a of the plurality of protruding portions 127 of the third small-diameter inner
circumferential portion 115 of the boot 16 is smaller in diameter than the small-diameter
outer circumferential surface 63c of the intermediate shaft portion 63 of the slide pin 33.
Therefore, as the engagement of the fitting shaft portion 64 with the guide hole 26 further
progresses, as illustrated in Fig. 2, the distal end surfaces 127a of the plurality of
20 protruding portions 127 of the third small-diameter inner circumferential portion 115
come into contact with the reduced diameter surface 63d of the intermediate shaft portion
63 of the slide pin 33. At this time, in the third small-diameter inner circumferential
portion 115, the passage portions 128 illustrated in Fig. 5 between the adjacent
protruding portions 127 cause a space 143 illustrated in Fig. 2 on the side closer to the
25 carrier connecting portion 82 than the third small-diameter inner circumferential portion
26
115 of the boot 16 to communicate with a space 144 on the side opposite to the carrier
connecting portion 82 of the third small-diameter inner circumferential portion 115 of the
boot 16. Therefore, the air discharged from the guide hole 26 to the space 143
according to the extent to which the fitting shaft portion 64 enters is smoothly discharged
5 from the space 143 to the space 144, thereby minimizing the air causing resistance when
fitting the fitting shaft portion 64 into the guide hole 26.
[0057]
In the disc brake 10 of the present embodiment illustrated in Fig. 1, when a
brake fluid is introduced between the cylinder portion 41 of the caliper 15 and a piston
10 (not illustrated) provided in the cylinder portion 41, the piston moves in the disc axial
direction and advances toward the disc 11 side. Then, the piston presses the pad 13 on
an inner side toward the disc 11. Thereby, the pad 13 on the inner side moves on the
carrier 12 in the disc axial direction and comes into contact with the disc 11.
[0058]
15 Also, due to a reaction force of this pressing, the caliper 15 slides the pair of
slide pins 33 against the pair of guide holes 26 of the carrier 12 and moves them toward
the inner side in the disc axial direction, and the pad 13 on an outer side is pressed
toward the disc 11 by the claw portion 43. Thereby, the pad 13 on the outer side moves
on the carrier 12 in the disc axial direction and comes into contact with the disc 11.
20 [0059]
As described above, the caliper 15 sandwiches the pair of pads 13 from both
sides with the piston (not illustrated) and the claw portion 43, presses them against the
disc 11, applies frictional resistance to the disc 11, and generates a braking force. When
the caliper 15 moves in the disc axial direction with respect to the carrier 12, an amount
25 of protrusion of the pair of slide pins 33 from the pair of guide holes 26 changes. The
27
pair of boots 16 expand and contract to follow the change in the amount of protrusion.
[0060]
In the disc brake described in Patent Literature 1, a small-diameter inner
circumferential portion of a bellows portion of a boot comes into contact with a pin over
5 the entire circumference. For this reason, it becomes resistance when discharging air
when the pin is fitted into a guide hole, and it may become resistance when fitting the pin
into the guide hole. In addition, since the small-diameter inner circumferential portion
of the bellows portion of the boot comes into contact with the pin over the entire
circumference, frictional resistance increases, which also causes a likelihood of
10 resistance being caused when fitting the pin into the guide hole.
[0061]
On the other hand, according to the present embodiment, the protruding portions
122 and the protruding portions 127 which protrude toward the radial inner side are
formed in the second small-diameter inner circumferential portion 113 and the third
15 small-diameter inner circumferential portion 115 in the middle of the bellows portion 83
of the boot 16 in the extending/contracting direction. Thereby, when the second
small-diameter inner circumferential portion 113 and the third small-diameter inner
circumferential portion 115 come into contact with the slide pin 33, the protruding
portions 122 and the protruding portions 127 come into contact with the slide pin 33, and
20 air can be circulated by the passage portions 123 and the passage portions 128 which are
adjacent to the protruding portions 122 and the protruding portions 127. Therefore, it is
possible to prevent the second small-diameter inner circumferential portion 113 and the
third small-diameter inner circumferential portion 115 from becoming resistance to air
discharge when the slide pin 33 is fitted into the guide hole 26, and it is also possible to
25 suppress frictional resistance. Therefore, it is possible to suppress decrease in
28
workability of assembling work.
[0062]
Among the small-diameter inner circumferential portions 113 and 115, the third
small-diameter inner circumferential portion 115 on the side close to the distal end of the
5 slide pin 33 is smaller in diameter than the second small-diameter inner circumferential
portion 113 on the side close to the base end of the slide pin 33. Among the
large-diameter inner circumferential portions 112 and 114, the maximum inner diameter
of the second large-diameter inner circumferential portion 114 on the side close to the
distal end of the slide pin 33 is smaller than the maximum inner diameter of the first
10 large-diameter inner circumferential portion 112 on the side close to the base end of the
slide pin 33. Therefore, the volume of the space 142 on the base end side of the slide
pin 33 serving as a buffer of the air discharged from the space 141 on the distal end side
of the slide pin 33 increases, and thus the air from the space 141 can be discharged
preferably. Therefore, it is possible to further minimize air causing resistance when
15 fitting the fitting shaft portion 64 into the guide hole 26. Therefore, it is possible to
further suppress the decrease in workability of assembling work.
[0063]
The boot 16 of the above embodiment may be modified as the boot 16 of a first
modified example illustrated in Fig. 7. In this first modified example, in place of the
20 above-described protruding portions 122 and 127, rib-shaped protruding portions 151
continuously extending from the second small-diameter inner circumferential portion 113
to the third small-diameter inner circumferential portion 115 are formed in the axial
direction of the boot 16. The protruding portions 151 protrude toward the radial inner
side from the inner circumferential surface 121a of the main body portion 121 of the
25 second small-diameter inner circumferential portion 113. The protruding portions 151
29
protrude toward the radial inner side also from an inner circumferential surface 152a of a
tapered tubular main body portion 152 of a third tapered tubular portion 103. The
protruding portions 151 protrude toward the radial inner side also from an inner
circumferential surface 153a of an annular main body portion 153 of the second
5 large-diameter inner circumferential portion 114. The protruding portions 151 protrude
toward the radial inner side also from an inner circumferential surface 154a of a tapered
tubular main body portion 154 of the fourth tapered tubular portion 104. The
protruding portions 151 protrude toward the radial inner side also from the inner
circumferential surface 126a of the main body portion 126 of the third small-diameter
10 inner circumferential portion 115. A plurality of protruding portions 151 are formed at
intervals in the circumferential direction of the boot 16.
[0064]
Therefore, in the second small-diameter inner circumferential portion 113,
passage portions 123 for bleeding air are formed to be recessed toward the radial outer
15 side from distal end surfaces 151a of the protruding portions 151 between the protruding
portions 151 adjacent to each other in the circumferential direction. In the third
small-diameter inner circumferential portion 115, passage portions 128 for bleeding air
are formed to be recessed toward the radial outer side from the distal end surfaces 151a
of the protruding portions 151 adjacent to each other between the protruding portions 151
20 adjacent to each other in the circumferential direction. A width of the protruding
portion 151 in the circumferential direction of the boot 16 is smaller than the interval
between the adjacent protruding portions 151.
[0065]
In this first modified example, the same effects as in the above embodiment can
25 be achieved.
30
[0066]
Further, the above embodiment may be modified as in a second modified
example illustrated in Figs. 8 and 9. In this second modified example, protruding
portions 161 having a bulging shape are formed in place of the above-described
5 protruding portions 122, having a protruding shape, of the second small-diameter inner
circumferential portion 113. A plurality of protruding portions 161 are formed at
intervals in the circumferential direction of the second small-diameter inner
circumferential portion 113, and a space surrounded by these protruding portions 161
forms a petal-shaped cross section as a whole. In the second small-diameter inner
10 circumferential portion 113, passage portions 162 for bleeding air are formed to be
recessed toward the radial outer side between protruding portions 161 adjacent to each
other in the circumferential direction. A width of the protruding portion 161 in the
circumferential direction of the boot 16 is larger than the interval between the adjacent
protruding portions 161. Also, although not illustrated, the third small-diameter inner
15 circumferential portion 115 can also be formed in a similar petal shape.
[0067]
Here, there is a likelihood of the protruding portion 161 for bleeding air in the
second modified example requiring a large amount of materials and thus costs being high,
but in the above-described embodiment, since increase only in local materials due to the
20 protruding protrusions 122 and 127 having a protruding shape is sufficient, the costs can
be reduced. In addition, while there is a likelihood of the protruding portion 161 of the
second modified example being easily deformed according to the pin diameter and a
clearance for air bleeding with respect to the slide pin 33 may not be easily secured, a
clearance for air bleeding is easily secured with respect to the slide pin 33 with the
25 protruding protrusions 122 and 127 of the above-described embodiment having a
31
protruding shape and high communication effect can be obtained. In addition, although
a contact area of the protruding portion 161 of the second modified example is increased
with respect to the slide pin 33, which may affect sliding resistance, sticking, or the like
of the slide pin 33, the protruding protrusions 122 and 127 of the above-described
5 embodiment having a protruding shape cannot easily affect such sliding resistance,
sticking or the like. In the second modified example, although when the bellows
portion 83 extends, there is a possibility of elongation strain applied to a rubber material
not being uniform due to the shape of the protruding portion 161 and durability may
decrease, it is possible to minimize decrease in durability in the above-described
10 embodiment.
[0068]
As a disc brake based on the above-described embodiment, for example, aspects
described below are conceivable.
As a first aspect, there is provided a carrier having a pair of pads respectively
15 disposed to face both sides of a disc and fixed to a vehicle across an outer circumferential
side of the disc, a caliper supported on the carrier to be movable in a disc axial direction
with a slide pin interposed therebetween and configured to press the pair of pads against
the disc, and a boot provided between the carrier and the caliper and having an
expandable/contractible bellows portion, the boot into which the slide pin is inserted.
20 The bellows portion includes at least two inwardly bent portions bent toward a radial
inner side, protruding portions protruding from an inner circumferential surface of each
of the inwardly bent portions toward an outer circumferential surface of the slide pin are
formed, and passage portions are formed adjacent to each of the protruding portions
when each of the protruding portions comes into contact with the outer circumferential
25 surface of the slide pin. Therefore, it is possible to minimize decrease in workability of
32
assembling work.
As a second aspect, in the first aspect, a plurality of protruding portions is
formed at intervals in a circumferential direction of the inwardly bent portion.
As a third aspect, in the first aspect or the second aspect, each of the protruding
5 portions is formed in a protruding shape.
As a fourth aspect, in the first aspect or the second aspect, each of the protruding
portions is formed in a rib shape which continuously extends over the at least two
inwardly bent portions in the axial direction of the boot.
As a fifth aspect, in the second aspect, each of the protruding portions is formed
10 in a bulging shape, and each of the protruding portions and the inner circumferential
surface of each of the inwardly bent portions are formed to have a petal-shaped cross
section.
[0069]
As a sixth aspect, in the first to fifth aspects, the bellows portion may alternately
15 have a small-diameter inner circumferential portion and a large-diameter inner
circumferential portion. Further, in the first to fifth aspects, a small-diameter inner
circumferential portion on a side close to a distal end of the pin may be smaller in
diameter than a small-diameter inner circumferential portion on a side close to a base end
of the pin. Further, in the first to fifth aspects, a large-diameter inner circumferential
20 portion on the side close to the distal end of the pin may be smaller in diameter than a
large-diameter inner circumferential portion on the side close to the base end of the pin.
According to such a configuration, it is possible to further minimize decrease in
workability of assembling work.
[Industrial Applicability]
25 [0070]
33
According to the above-described disc brake, it is possible to minimize decrease
in workability of assembling work.
[Reference Signs List]
[0071]
5 10 Disc brake
11 Disc
12 Carrier
13 Pad
15 Caliper
10 16 Boot
33 Pin
83 Bellows portion
111 First small-diameter inner circumferential portion (small-diameter inner
circumferential portion)
15 112 First large-diameter inner circumferential portion (large-diameter inner
circumferential portion)
113 Second small-diameter inner circumferential portion (small-diameter
inner circumferential portion in the middle in an extending/contracting direction)
114 Second large-diameter inner circumferential portion (large-diameter
20 inner circumferential portion)
115 Third small-diameter inner circumferential portion (small-diameter
inner circumferential portion in the middle in an extending/contracting direction)
116 Third large-diameter inner circumferential portion (large-diameter inner
circumferential portion)
25 122, 127, 151, 161 Protruding portion

I/We Claim:
[Claim 1]
A disc brake comprising:
a carrier having a pair of pads respectively disposed to face both sides of a disc
5 and fixed to a vehicle across an outer circumferential side of the disc;
a caliper supported on the carrier to be movable in a disc axial direction with a
slide pin interposed therebetween and configured to press the pair of pads against the
disc; and
a boot provided between the carrier and the caliper and having an
10 expandable/contractible bellows portion, the boot into which the slide pin is inserted,
wherein
the bellows portion includes at least two inwardly bent portions bent toward a
radial inner side, protruding portions protruding from an inner circumferential surface of
each of the inwardly bent portions toward an outer circumferential surface of the slide
15 pin are formed, and passage portions are formed adjacent to each of the protruding
portions when each of the protruding portions comes into contact with the outer
circumferential surface of the slide pin.
[Claim 2]
The disc brake according to claim 1, wherein a plurality of protruding portions is
20 formed at intervals in a circumferential direction of the inwardly bent portion.
[Claim 3]
The disc brake according to claim 1 or 2, wherein each of the protruding
portions is formed in a protruding shape.
[Claim 4]
25 The disc brake according to claim 1 or 2, wherein each of the protruding
35
portions is formed in a rib shape which continuously extends over the at least two
inwardly bent portions in the axial direction of the boot.
[Claim 5]
The disc brake according to claim 2, wherein each of the protruding portions is
5 formed in a bulging shape, and each of the protruding portions and the inner
circumferential surface of each of the inwardly bent portions are formed to have a
petal-shaped cross section.
[Claim 6]
The disc brake according to any one of claims 1 to 5, wherein:
10 the bellows portion alternately has a small-diameter inner circumferential
portion and a large-diameter inner circumferential portion,
a small-diameter inner circumferential portion on a side close to a distal end of
the pin is smaller in diameter than a small-diameter inner circumferential portion on a
side close to a base end of the pin, and
15 a large-diameter inner circumferential portion on the side close to the distal end
of the pin is smaller in diameter than a large-diameter inner circumferential portion on
the side close to the base end of the pin.