SPECIFICATION
YOKE F'OR CROSS SHAFT UNIVERSAL JOINT
TECHNICAL FIELD
[0001]
The invention relates to an improved yoke constituting, for example, a cross
shaft universal joint ( cardan joint) for connecting together rotation shafts constituting a
vehicle steering apparatus in a torque transmittable manner .
. '
10 BACKGROUND ART
[0002]
A vehicle steering apparatus is structured as shown in Fig. 12. The
movement of a steering wheel I to be operated by a driver is transmitted to an input
shaft 6 of a steering gear unit 5 through a steering shaft 2, a universal joint 3, an
15 intermediate shaft 4 and another universal joint 3. And, a pair of right and left tie
rods 7, 7 are pushed and pulled by a rack and pinion mechanism built in the steering
gear unit 5 to thereby apply proper steering angles to a pair of right and left steering
wheels according to the operation amount of the steering wheel I. · Here, as the
intermediate shaft 4, generally, there is used a shaft structured such that, as shown in
2 0 Fig. 13, the one-side ends of an outer shaft 8 and an inner shaft 9 are serration engaged
with each other to thereby enable torque transmission and, in a collision accident,
contraction. The universal joints 3, 3 are connected to the other-side ends of the
shafts 8, 9.
[0003]
25 As the universal joints 3, 3 to be incorporated into the steering apparatus,
1
there are used, for example, such cross shaft universal joints as disclosed in the patent
document I. Description is given of a conventional structure of one of yokes
constituting such cross shaft universal joints and including a basic structure to be
aimed at by the invention with reference to Figs. 14 to 16E. A yoke I 0 of the
5 conventional structure is a' so called press yoke which is formed by punching and
bending sequentially a metal plate such as steel material plate using a press, and
includes a base part II and a pair of connecting arm parts 12, 12.
[0004]
The base part 11 has a partially-lacking cylindrical shape and includes a
. 1 I
10 discontinuous portion (slit) 13 for enabling expansion and compression of the inside
diameter of the base part 11 in one circumferential location thereof. It also includes
first and second flange portions 14, 15 while they are sandwiching the discontinuous
portion 13 from both sides in the circumferential direction thereof. It further includes
a female serration 16 in the inner peripheral surface thereof. Also, because a metal
15 plate is folded back, the frrst and second flange portions 14, 15 have a double thickness
dimension of a metal plate. The frrst and second flange portions 14, 15 have, at the
mutually matching positions thereof, a through hole 17 and a screw hole 18 while they
are respectively twisted with respect to the axis of the base part 11. Also, in the free
state of the yoke 10, the first and second flange portions 14, 15 are substantially
2 0 parallel to each other, while the through hole 17 and screw hole 18 are arranged
concentrically with each other.
[0005]
The connecting arm parts 12, 12 extend in the axial direction from such two
locations of the axial-direction one end edge (in Fig. 14, upper end edge) of the base
2 5 part 11 as are opposed to each other in the diameter direction of the base part 11.
2
Also, the arrangement direction (in Figs. 14 and 15, right and left direction) of the
connecting arm parts 12, 12 is circumferentially coincident (parallel to) with the
arrangement direction (in Fig. 15, right and left direction) of the first and second flange
portions 14, 15. And, the connecting arm parts 12, 12 include mutually concentric
5 circulm holes 19, 19 in thei~ respective tip portions. Also, the axes of the circulm
holes 19, 19 and the axes of the through hole 17 and screw hole 18 me arranged
pmallel to each other. [0006]
As shown in Fig. 16A, the yoke 10 having the above structure is made of a
flat material plate 22 which includes a base plate part 20 and a pair of tongue-like pmts
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1 0 21, 21. Firstly, the two ends of the base plate part 20 of this material plate 22 are
respectively folded back 180° in their respective middle portions, thereby providing a
first intermediate material 23 as shown in Fig. 16B. Next, the first intermediate
material 23 is pressed between a pair of dies to be deformed plastically, thereby
providing a second intermediate material 24 as shown in Fig. 16C. In the second
15 intermediate material24, the tongue-like parts 21, 21 to provide the paired connecting
arm parts 12, 12 are curved in a partially cylindrical manner, the base end near portions
of the tongue-like parts 21, 21 me bent substantially in a crank shape, and the
intermediate portions of the tongue-like parts 21, 21 to the leading end near portions
thereof me offset with respect to the base plate part 20. Next, of the thus-structured
2 0 second intermediate material 24, the central portion of the base plate part 20 is slightly
curved to provide a third intermediate material 25 as shown in Fig. l6D. Next, the
base plate part 20 of the third intermediate material 25 is curved further to provide a
fourth intermediate material 26 as shown in Fig. 16E. In this state, there are formed
the base part ll and the paired connecting arm parts 12, 12 to be equipped in the yoke
2 5 10 after completed. Finally, the through hole 17 and screw hole 18 are formed in the
3
first, second flange portions 14, 15 constituting the base part 11, the female scnation
16 is formed in the inner peripheral surface of the base part 11, and the circular holes
19, 19 are formed in the connecting arm parts 12, 12, thereby providing the yoke 10 as
shown in Figs. 14 and 15.
5 [0007]
As shown in Figs. 16A to 18, to assemble a cross shaft universal joint using
the above-produced yoke 10, inside the circular holes 19, 19 formed in the tip portions
of the connecting ann parts 12, 12, there are pivotally supported the two ends of one
shaft part 28a of a pair of shaft parts 28a, 28b constituting a cross shaft 27. Thus, cup
, ; I
10 bearings 29, 29 are internally engaged with and fixed to the insides of the circular
holes 19, 19.
[0008]
The cup bearings 29, 29 respectively conespond to shell-type needle bearings
and include bottomed cylindrical cups 30, 30 corresponding to shell-type outer rings,
15 and include bottomed cylindrical cups 30, 30 corresponding to shell-type outer rings
and multiple needles 31, 31. To assemble these cup bearings 29, 29, while the shaft
part 28a of the cross shaft 27 is inserted into the circular holes 19, 19, the cups 30, 30
with the needles 31, 31 ananged along the inner peripheral surfaces thereof may be
pressure inserted into the circular holes 19, 19 from the outer-surface side openings of
2 0 the connecting arm parts 12, 12. Thus, the two ends of the shaft part 28a are rotatably
supported on the yoke 10. Here, after completion of such assembling operation, the
inner peripheral surfaces of the cups 30, 30 function as the outer ring raceways of the
cup bearings 29, 29, while the outer peripheral surface of the shaft part 28a functions
as the inner ring raceways of the cup bearings 29, 29.
25 [0009]
4
Also, for assembling a steering apparatus, to connect and fix the base part 11
of the yoke 10 to the end of a rotation shaft constituted of any one of the steering shaft
2, intermediate shaft 4 and input shaft (see Fig. 12) in a torque transmittable mam1er,
firstly, in the free state of the yoke 10, the end of the rotation shaft is inserted into the
5 inside of the center hole (~erration hole) of the base part 11. Thus, the female
serration 16 formed in the inner peripheral surface of the base part 11 is serration
engaged with a male serration formed in the outer peripheral surface of the end of the
rotation shaft. Next, as shown in Figs. 17 and 18, a bolt 32 is inserted through the
through hole 17 and is threadedly engaged with the screw hole 18, and is further
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10 tightened. Thus, the width of the discontinuous part 13 is elastically narrowed,
thereby reducing the diameter of the base part 11 elastically. As a result, the surface
pressure of the serration engaged part increases, whereby the base part 11 is connected
and fixed to the end of the rotation shaft in a torque transmittable manner.
[0010]
15 In the yoke 10 having the above structure, for reason of secunng the
assembling workability of the cup bearings 29, 29, the end of the shaft part 28a
constituting the cross shaft 27 is inserted into the radial-direction insides of the needles
31, 31 constituting the cup bearings 29, 29 with a certain degree of clearance.
Therefore, when in use, there is a possibility that the end of the shaft part 28a can
2 0 shake in the diameter direction (radial direction) relative to the cup bearings 29, 29 and
can generate strange sounds. Also, such shaking motion can probably become
excessively large with long use.
[00 11]
In view of the above circumstances, for example, the patent document 2
2 5 discloses an invention in which the peripheral part of a circular hole of a connecting
5
arm part, constituting a yoke, with a cup bearing being pressure inserted therein is
plastically deformed to thereby suppress occurrence of shaking motion between the
cup bearing and the shaft part of a cross shaft. Also, for example, the patent
document 3 discloses an invention in which the shape of a cup constituting a cup
5 bearing is worked (the cylindrical part thereof is deformed) to thereby suppress
occurrence of shaking motion between the cup bearing and the shaft part of a cross
shaft. However, in both of the inventions of the patent documents 2 and 3, for
suppression of occurrence of shaking motion, exclusive working on the connecting arm
part or cup is necessary. This increases the working cost of the cross shaft universal
• ; I
10 joint, thereby inevitably leading to rise of cost thereof.
Here, in the conventional structure shown m Figs. 14 to 19, the
circumferential phases of the arrangement direction of the axes of the through hole 17,
screw hole 18 and the arrangement direction of the circular holes 19, 19 are coincident
with each other (are arranged parallel to each other). Thus, even when the first,
15 second flanges 14, 15 are deformed in their mutually approaching directions by
tightening the bolt 32, as shown by a thick arrow in Fig. 19, the connecting arm parts
12, 12 are simply flexually deformed in the mutually approaching directions in the
axial direction of the circular holes 19, 19 which is a direction parallel to the
arrangement direction of the first, second flange portions 14, 15. That is, there does
2 0 not occur such deformation as can reduce the above-mentioned shaking motion.
RELATED ART REFERENCE
PATENT DOCUMENT
[0012]
25 Patent Document 1: JP-A- 2011-220426
6
Patent Document 2: JP-A- 2003-28188
Patent Document 3: JP-A- 2007-327590
SUMMARY OF THE INVENTION
5 PROBLEMS TO BE SOLVED BY THE INVENTION
[0013]
In view of the above circumstances, the invention aims at realizing at low
costs a yoke for a cross shaft universal joint which can suppress occurrence of shaking
motion between a bearing incorporated in a circular hole and the end of the shaft part
, ; I
10 of a cross shaft rotatably supported by the bearing.
MEANS FOR SOLVING THE PROBLEMS
[0014]
A yoke for a cross shaft universal joint of the invention includes: a base part
15 for connecting and fixing the end of a rotation shaft thereto; and a pair of connecting
arm parts respectively extending in the axial direction from two diametrically opposite
positions corresponding to the base part at one axial end edge of the base part, wherein:
the pair of connecting arm parts include a pair of circular holes formed at tip portions
thereof to be concentric with each other, the pair of circular holes being configured to
2 0 pivotally support the end of a shaft part, forming a cross shaft, through bearings; the
base part has a partially-lacking cylindrical shape and includes a discontinuous part in
one circumferential location of the base part, the one circumferential location existing
between the paired connecting arm parts and being 90° out of phase with the paired
connecting arm parts in the circumferential direction; the base part includes: a pair of
2 5 flange parts formed across the discontinuous part; and a pair of mounting holes formed
7
in the mutually matching portions of the pair of flange parts; and the paired mounting
holes are formed such that the respective axes thereof are inclined relative to the axes
of the paired circular holes, and mutually approaching forces are applied to the paired
connecting arm parts in a direction inclined relative to the axes of the circular holes by
5 putting the paired flange paTts nearer to each other up to a dimension capable of fixing
the end of the rotation shaft within the base part.
Here, the above bearing is not limited to a cup bearing (shell type needle
bearing), but there can be employed various bearings such as a sliding bearing.
[0015]
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10 Particularly, in the cross shaft universal joint yoke of the invention, the paired
mounting holes are formed such that their respective axes are inclined relative to the
axes of the paired circular holes. Thus, in a state where a fastening member such as a
bolt is inserted into the paired mounting holes and is fastened to thereby put the paired
flange parts nearer to each other up to a dimension capable of fixing the end of the
15 rotation shaft within the base part, the axis of the fastening member is inclined relative
to the axes of the paired circular holes.
And, by putting the paired flange parts nearer to each other up to a dimension
capable of fixing the end of the rotation shaft within the base part, mutually
approaching forces are applied to the paired connecting arm parts in a direction
2 0 inclined relative to the axes of the paired circular holes.
[0016]
In enforcing the above cross shaft universal joint yoke of the invention, for
example, when the yoke is viewed from the lateral surface direction, the axial direction
of the axes of the paired mounting holes is inclined relative to the axial direction of the
2 5 axes of the paired circular holes.
8
5
Also, in enforcing the above cross shaft universal joint yoke of the invention,
for example, in view from the axial direction of the rotation shaft, the axial direction of
the axes of the paired mounting holes is inclined relative to the axial direction of the
axes of the paired circular holes.
[0017]
Further, in enforcing the above cross shaft universal joint yoke of the
invention, for example, the discontinuous part is inclined relative to the axial direction
of the base part in such a manner that it crosses the axes of the paired mounting holes
at right angles.
10 [0018]
15
Further, in enforcing the above cross shaft universal joint yoke of the
invention, for example, the mounting hole formed in one of the paired flange parts is
formed as a through hole, whereas the mounting hole formed in the other flange part is
formed as a screw hole.
ADVANTAGES OF THE INVENTION
[0019]
According to the above structured yoke for a cross shaft universal joint of the
invention, a structure capable of suppressing occurrence of shaking motion between
2 0 the bearings incorporated in the circular holes and the end of the shaft part of the cross
shaft supported rotatably by the bearings can be realized at low costs.
That is, in the invention, since the axes of the paired mounting holes
respectively formed in the paired flange parts are inclined relative to the ;axes of the
paired circular holes respectively formed in the paired connecting arm parts, by
2 5 tightening a fastening member such as a bolt inserted through the mounting holes
9
formed in the paired flange parts to put the flange parts nearer to each other, mutually
approaching forces can be applied to the paired connecting arm parts in directions
inclined relative to the axes of the paired circular holes. This can prevent formation
of a radial clearance between the bearings incorporated in the circular holes and the
5 end of the shaft part of the' cross shaft inserted into the bearings, thereby enabling
suppression of occurrence of shaking motion between the bearings and the end of the
shaft part. Also, in the invention, since there is eliminated the need for exclusive
working for suppression of such shaking motion occurrence, the working cost of the
yoke for a cross shaft universal joint and thus a cross shaft universal joint including the
• 1 I
10 yoke for a cross shaft universal joint of the invention can be reduced, thereby enabling
cost reduction.
BRIEF DESCRIPTION OF THE DRAWINGS
(0020]
15 Fig. 1 is a side view of a yoke for a cross shaft universal joint according to a
first embodiment of the invention.
Fig. 2 is an end view of the yoke of Fig. 1 when viewed from below.
Fig. 3 is a partially cut-out side view of the yoke for a cross shaft universal
joint, showing a state where the cross shaft is supported by a cup bearing incorporated
2 0 in the yoke.
Fig. 4 is a side view of a yoke for a cross shaft universal joint according to a
second embodiment of the invention.
Fig. 5 is an end view of the yoke of Fig. 4 when viewed from below.
Fig. 6 is a section view taken along the VI-VI line of Fig. 4, showing a state
2 5 where the cross shaft is supported by a cup bearing incorporated in the York.
10
Fig. 7 is a side view of a yoke for a cross shaft universal joint according to a
third embodiment of the invention.
Fig. 8 is an end view of the yoke of Fig. 7 when viewed from below.
Fig. 9 is a side view of a yoke for a cross shaft universal joint according to a
5 fourth embodiment of the in~ention.
Fig. 10 is an end view of the yoke of Fig. 9 when viewed from below.
Fig. 11 is a partially cut side view of a yoke according to a modification of the
invention.
Fig. 12 is a perspective view of an example of a steering apparatus with a
, 1 I
10 universal joint incorporated therein.
Fig. 13 is a partially cut side view of an intermediate shaft with cross shaft
universal joints assembled to the two ends thereof.
Fig. 14 is a side view of a yoke having a conventional structure.
Fig. 15 is an end view of the yoke of Fig. 14 when viewed from below.
15 Figs. 16A to 16E are typical views of a method for manufacturing the yoke of
Fig. 14 having the conventional structure, showing the sequence of the steps thereof.
Fig. 17 corresponds to Fig. 14 and shows how a cup bearing incorporated in
the yoke supports a cross shaft.
Fig. 18 corresponds to Fig. 15 and shows a state where a bolt is fastened to the
20 yoke.
Fig. 19 is a section view of the yoke, taken along the XIX-XIX line of Fig. 17.
MODES FOR CARRYING OUT THE INVENTION
[0021] [First Embodiment]
25 Figs. 1 to 3 show a yoke for a cross shaft universal joint according to a first
11
embodiment of the invention. Here, a yoke for a cross shaft universal unit of the
invention including this embodiment is characterized in that the axes of a through hole
17a and a screw hole 18a respectively formed in first and second flange parts 14a, 15a
are inclined relative to the axes of circular holes 19a, 19 respectively formed in a pair
5 of connecting arm parts 12~, 12a. The structures and operations of the remaining
parts thereof are similar to those of the above-mentioned conventional structure of Figs.
14 to 19. Therefore, the equivalent parts are given the same designations and thus the
duplicated description thereof is omitted or simplified. Thus, description is given
below mainly of the characteristic parts of this embodiment.
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10 [0022]
The yoke lOa of this embodiment is a so called press yoke to be formed by
enforcing punching and bending operations sequentially on a metal plate such as a
steel member using a press, and includes a base part 11 a and a pair of connecting arm
parts 12a, 12a formed such that they are extended in the axial direction from such two
15 locations of the axial-direction one end edge (in Figs. 1 and 3, upper end edge) of the
base part 11 a as are opposed to each other in the diameter direction of the base part 11 a.
The connecting arm purls 12a, 12a includes in the tip portions thereof a pair of circular
holes 19a, 19a formed concentrically with each other and in the thickness direction of
the connecting arm parts 12a, 12a.
20 [0023]
.,
I
The base part lla has a partially lacking cylindrical shape which includes: a
discontinuous part 13 penetrating in the axial direction therethrough in one
circumferential location of the base part, the one circumferential location being 90° out
of phase with the connecting arm parts 12, 12 in the circumferential direction; and the
2 5 first and second flange parts 14a and l5a in the two locations of the base part
12
sandwiching the discontinuous part 13a from the two circumferential sides. Since the
metal plate is folded back, the first and second flange parts l4a and 15a each have a
double thickness dimension of a metal plate, and the arrangement direction of the first
and second flange parts 14a and 15a is coincident with the arrangement direction of the
5 connecting arm parts 12, 12. Also, the first and second flange parts 14a and 15a
include a through hole 17a and a screw hole 18a, formed concentrically with each other,
in the mutually matching locations thereof.
[0024]
Particularly, in this embodiment, the through hole 17a and screw hole 18a are
• 1 l
10 formed in a direction inclined relative to the axes of the circular holes 19a, 19a.
Specifically, the axes of the through hole 17a and screw hole 18a are inclined 5° to 45°,
preferably, 10° to 20° (in the illustrated example, about 10°) in the axial direction of
the base part lla (in Figs. 1 and 3, the vertical direction) relative to the axes of the
circular holes 19a, 19a (are inclined in parallel to virtual lines respectively
15 perpendicular to the axes of the circular holes 19a, 19a and the axis of the base part 11 a
and around a virtual line passing through the axes of the through hole 17a and screw
hole 18a). That is, when the yoke is viewed from the side surface direction (a
direction perpendicular to the sheet of Fig. 1, that is, a direction along a plane passing
through the axis of the base part 11 b and 90° out of phase with the paired connecting
2 0 arms 12a, 12a in the circumferential direction, the axial direction Yl of the through
hole 17a and screw hole 18a is inclined relative to the axial direction X1 of the paired
circular holes 19a, l9a (the axial direction Yl of the through hole 17a and screw hole
18a and the axial direction Xl of the paired circular holes 19a, 19a are not parallel to
each other).
25 Here, an angle (inclination angle) between the axes of the through hole 17a
13
5
and screw hole !Sa and the axes of the circular holes 19a, 19a can be decided properly
according to the shape of the yoke 1 Oa (particularly, the size of the rigidity of the
connecting arms 12a, 12a), the size of a radial clearance between a cup bearing 29 and
a shaft part 28a (to be discussed later), and the like.
[0025]
As shown in Figs. 3 and 4, to assemble a cross shaft universal joint using the
above produced yoke I Oa, the two ends of one shaft part 28a of the paired shaft parts
28a (28b) constituting the cross shaft 27 are pivotally supported on the insides of the
circular holes 19a, 19a formed in the tip portions of the connecting arm parts 12a, 12a.
10 [0026]
The cup bearings 29, 29 respectively correspond to shell type needle bearings,
and include bottomed cylindrical cups 30, 30 corresponding to shell type outer rings
and multiple needles 31, 31. The cup 30 is formed by bending a hard metal plate
such as a carbon steel plate or a case hardened steel plate using plastic working such as
15 deep drawing, and includes a cylindrical part 33, a bottom part 34 and an inward flange
part 35. The bottom part 34 covers the whole of the axial-direction one end side (in a
state where the cup beming is assembled into the circular hole 19a, the outer surface
side of the connecting arm part 12) of the cylindrical part 33. Also, the inwmd flange
part 35 is arranged to be folded radially inward from the axial-direction other end side
2 0 (in a state where the cup bearing is assembled into the circular hole 19a, the itmer
surface side of the connecting mm part 12a) of the cylindrical part 33. And, the
above-structured cups 30, 30 are pressure inserted into the circular holes 19a, 19a and,
of the outer surfaces of the connecting = parts 12a, 12a, the opening edges of the
circular holes !9a, 19a are plastically deformed radially inwmd to form caulking parts
2 5 (not shown), thereby preventing the cups 30, 30 from moving outwardly of the circulm
14
holes 19a, 19a. Also, the two ends of the shaft part 28a constituting the cross shaft 27
are respectively inserted into the radial insides of the needles 31, 31. Thus, the two
ends of the shaft part 28a are rotatably supported on the yoke I Oa. Here, in the yoke
I Oa of this embodiment as well, the ends of the shaft part 28a can be inserted into the
5 radial insides of the needles 31 , 31 while having a certain degree of clearance in a
stage where the two ends of the shaft part 28a are inserted into the radial insides of the
needles 31, 31 (in a state before the bolt 32 is fastened), similarly to the conventional
structure. This prevents the assembling workability of the cup bearing 29, 29 from
being lowered.
. ~ l
10 [0027]
Also, to connect and fix the base part 11 a of the yoke 10 of this embodiment
to the end of the rotation shaft in a torque transmittable manner, the end of the rotation
shaft is inserted into the inside of the center hole (serration hole) of the base part !Ia in
the free state of the yoke I Oa. Thus, the female serration 16a formed in the inner
15 peripheral surface of the base part 11 a and a male serration formed in the outer
peripheral surface of the end of the rotation shaft are serration engaged with each other.
Next, as shown in Fig. 3, a bolt (a circular washer equipped bolt) 32 is inserted through
the through hole 17a and is threadedly engaged with the screw hole 18a, and is
fastened further.. Thus, since the width of the discontinuous part 13a is elastically
2 0 narrowed (the frrst and second flange parts 14a and 15a are put nearer to each other),
the base part 11 a is elastically reduced in diameter. As a result, the surface pressure
of the serration engaged part increases, whereby the base part 11 a is connected and
frxed to the end of the rotation shaft in a torque transmittable manner. In this
embodiment, since the axes of the through hole 17a and screw hole 18a are inclined
25 relative to the axes of the circular holes 19a, 19a, in a state where the bolt 32 is
15
fastened, the axis of the bolt 32 is inclined relative to the axes of the circular holes 19a,
19a.
[0028]
According to the above-structured yoke 1 Oa for a universal joint of this
5 embodiment, a structure capable of suppressing occurrence of shaking motion between
the cup bearings 29, 29 assembled into the circular holes 19a, 19a and the end of the
shaft part 28a of the cross shaft 27 rotatably supported by the cup bearings 29, 29 can
be realized at low costs.
[0029]
. ~ l
10 That is, in this embodiment, the axes of the through hole 17a and screw hole
18a respectively formed in the first and second flange parts 14a and !Sa are inclined
relative to the axes of the circular holes 19a and 19a formed in the connecting arm
parts 12a and 12a. Therefore, by fastening the bolt 32 to put the first, second flange
parts 14a, !Sa nearer to each other, mutually approaching forces can be applied to the
15 connecting arm parts 12a, 12 in directions inclined in the axial direction of the base
part lla relative to the axes of the circular holes 19a, 19a, as shown by thick arrows in
Fig. 3. More specifically, the radial inner surface of the needle 31 situated on the
upper side of Fig. 3, of the needles 31, 31 constituting the cup bearing 29 arranged on
the left side of Fig. 3, is pressed down from above against the outer peripheral surface
2 0 of the left end in Fig. 3 of the ends of the shaft part 28a. Further, the radial inner
surface of the needle 31 situated on the lower side of Fig. 3, of the needles 31, 31
constituting the cup bearing 29 arranged on the right side of Fig. 3, is pressed upward
from below against the outer peripheral surface of the right end in Fig. 3 of the two
ends of the shaft part 28a. This can prevent formation of a radial clearance between
25 the cup bearings 29, 29 incorporated in the circular holes 19a, 19a and the two ends of
16
the shaft part 28a constituting the cross shaft 27 inserted into the insides of the cup
bearings 29, 29, thereby enabling suppression of occurrence of shaking motion
between the cup bearings 29, 29 and the two ends of the shaft part 28a. Also, in this
embodiment, the structure providing such effects can be realized simply by changing
5 the forming direction ofthe'through hole 17a and screw hole 18a, while eliminating
the need for exclusive working for suppressing the shaking motion as in the inventions
disclosed in the above-cited patent documents 2 and 3. Therefore, the working cost
of the yoke 1 Oa of this embodiment and thus the cross shaft universal joint
incorporating the yoke 1 Oa therein can be restricted, thereby enabling cost reduction.
• t I
10 [0030] [Second Embodiment]
Figs. 4 to 6 show a yoke for a cross shaft universal joint according to a second
embodiment of the invention. In the yoke lOb of this embodiment, as shown in Fig. 5,
when viewed from the axial direction (the axial direction of the base part 11 b), the
axial direction Y1 of the axes of the through hole 17b and screw hole 18b is inclined
15 relative to the axial direction Xl of the axes of a pair of circular holes 19, 19. That is,
the axes of the through hole 17b and screw hole 18b respectively formed in the first
and second flange parts l4b and 15b of the base part 11 b are inclined toward the
forming direction of the discontinuous part 13 of the base part llb (the radial direction
of the base part ll b) relative to the axes of the circular holes 19a and l9a respectively
2 0 formed in a pair of connecting ann parts l2a and l2a (are inclined around a virtual line
parallel to the axis of the base part ll b and passing through the axes of the through
hole 17b and screw hole 18b. Here, in this embodiment, the axial direction XI of the
axes of a pair of circular holes 19 and 19 is coincident with the circumferential
intermediate positions of the paired connecting arm parts 12a and 12a.
25 Thus, when the bolt 32 is inserted through the through hole 17b, is threadedly
17
engaged with the screw hole 18b and is further tightened to thereby put the first,
second flange parts 14b, 15b nearer to each other, such mutually approaching forces as
shown by thick arrows in Fig. 5 can be applied to the axes of the circular holes 19a,
19a in a direction inclined toward the formation direction of the discontinuous part 13.
5 The structures and operations of the remaining parts are similar to those of the
first embodiment.
[0031] [Third Embodiment]
Figs. 7 and 8 show a yoke for a cross shaft universal joint according to a third
embodiment of the invention. In the yoke 1 Oc of this embodiment, the axial direction
, 1 I
10 Yl of the axes of a through hole 17 and a screw hole 18 respectively formed in the first
and second flange parts 14 and 15 is formed to extend along the arrangement direction
of the first and second flange parts 14 and 15 (the expansion direction of the
discontinuous part 13). Meanwhile, the axial direction XI of the axes of the circular
holes 19b and 19b respectively formed in a pair of connecting arm parts 12b and 12b is
15 inclined relative to the arrangement direction of the paired connecting arm parts 12b
and 12b in the axial direction of the base part 11. Thus, the circular holes 19b and
19b are formed such that the axes thereof are inclined toward the axial direction of the
base part 11 relative to the axes of the through hole 17 and screw hole 18.
[0032]
20 With the universal joint yoke 1 Oc of this embodiment as well, the bolt 32 is
inserted through the through hole 17, is threadedly engaged with the screw hole 18 and
is further fastened to put the first and second flange parts 14 and 15 nearer to each
other, thereby enabling prevention of formation of a radial clearance between the cup
bearings 29, 29 incorporated inside the circular holes 19b, 19b and the two ends of a
2 5 shaft part 28a constituting a cross shaft 27 insetied inside the cup bearings 29, 29 and
18
thus enabling suppression of occurrence of shaking motion between the cup bearings
29, 29 and the two ends of the shaft part 28a.
[0033] [Fourth Embodiment]
Figs. 9 and I 0 show a yoke for a cross shaft universal joint according to a
5 fourth embodiment of the in~ention. With the yoke I Od of this embodiment as well,
the axes of the through hole 17 and screw hole 18 respectively formed in the first and
second flange parts 14 and 15 are formed to extend along the arrangement direction of
the first and second flange parts 14 and 15 (the expansion direction of the
discontinuous part 13).
10 [0034]
Meanwhile, in this embodiment, when viewed from the axial direction of the
rotation shaft, the axial direction XI of the axes of the through hole 17b and screw hole
18b is formed in a direction inclined relative to the axial direction Yl of the axes of the
circular holes 19c and 19c. Specifically, in this embodiment, the above position
15 relation is given by shifting the axes XI of the circular holes 19c and 19c in view from
the axial direction of the rotation shaft to the circumferential direction from the
circumferential intermediate positions of the paired connecting arm parts 12c and 12c.
[0035]
With the universal joint yoke lOd of this embodiment as well, the bolt 32 is
2 0 inserted t.'rrough the through hole 17, is threadedly engaged with the screw hole 18 and
is further fastened to put the first and second flange parts 14 and 15 nearer to each
other, thereby enabling prevention of occurrence of shaking motion between the cup
bearings 29, !29 incorporated inside the circular holes 19c, 19c and the ends of the shaft
part 28a of the cross shaft 27 rotatably supported by the cup bearings 29 and 29.
25 [0036]
19
Here, the invention is not limited to the above embodiments but can be
changed or improved properly.
For example, like a yoke I Oa' according to a modification shown in Fig. ll, a
discontinuous part 13a sandwiched by first and second flanges 14a and !Sa may also
5 be inclined relative to the ~ial direction of a base part 11 a in such a manner that it
crosses the axes of the through hole 17b and screw hole 18b at right angles.
[0037]
Also, in enforcing the invention, the mounting holes respectively formed in
the paired flange parts are not limited to the structure that, as in the above respective
, 1 !
10 embodiments, one is formed as a through hole and the other is formed as a screw hole.
For example, there can also be employed a structure that the paired mounting holes are
respectively formed as through holes and a nut is pressure inserted and fixed to one of
the through holes. Also, the thickness dimension of the flange part is not limited to a
double thickness dimension of a metal plate used as a material plate. Also, the
15 structures of the above respective embodiments can also be enforced in combination
with each other.
[0038]
Also, the bearing to be incorporated into the circular hole formed in the
leading end of the connecting arm part is not limited to a cup bearing (shell type needle
2 0 bearing), but there may be employed various bearings such as a sliding bearing having
a shape with a needle omitted from a cup bearing. Also, the universal joint yoke
manufacturing method of the invention is not limited to a method similar to a yoke
manufacturing method having a conventional structure, but another step can be added
thereto or omitted therefrom; and other various methods can also be employed. Also,
2 5 the invention is not limited to a press yoke but can also be applied to a forged yoke.
20
[0039]
This application is based on the Japanese Patent Application No. 2014-101232
filed on May 15,2014, Japanese Patent Application No. 2015-090904 filed on April28,
2015 and Japanese Patent Application No. 2015-090905 filed on April 28, 2015, and
5 thus the contents thereof are' incorporated herein for reference.
10
15
20
25
DESCRIPTION OF REFERENCE NUMERALS AND SIGNS
[0040]
1: Steering wheel
' I 2: Steering shaft
3: Universal joint
4: Intermediate shaft
5: Steering gear unit
6: Inputshaft
7: Tie rod
8: Outer shaft
9: Inner shaft
10, lOa, lOb, lOc, lOd: Yoke
11, lla, llb: Base part
12, 12a, 12b, 12c: Connecting arm part
13, 13a: Discontinuous part (slit)
14, 14a, 14b: First flange part
15, 15a, 15b: Second flange part
16: Female serration
17, 17a, 17b: Through hole
21
18,18a,18b: Screw hole
19, 19a, 19b, 19c: Circular hole
20: Base pI ate part
21: Tongue-like part
5 22: Material pl~te
23: First intermediate material
24: Second intermediate material
25: Third intermediate material
26: Fourth intermediate material
' I
10 27: Cross shaft
28a, 28b: Shaft part
29: Cup bearing
30: Cup
31: Needle
15 32: Bolt
33: Cylindrical part
34: Bottom part
35: Inward flange part

CLAIMS
1. A yoke for a cross shaft universal joint, comprising:
a base part for connecting and fixing the end of a rotation shaft thereto; and
5 a pair of connecting arm parts respectively extending in the axial direction
from two diametrically opposite positions corresponding to the base part at one axial
end edge of the base part, wherein:
the pair of connecting arm parts include a pair of circular holes formed at tip
portions thereof to be concentric with each other, the pair of circular holes being
' 1 I
10 configured to pivotally support the end of a shaft part, forming a cross shaft, through
bearings;
the base part has a partially-lacking cylindrical shape and includes a
discontinuous part in one circumferential location of the base part, the one
circumferential location existing between the paired connecting arm parts and being
15 90° out of phase with the paired connecting arm parts in the circumferential direction;
the base part includes: a pair of flange parts formed across the discontinuous
part; and a pair of mounting holes formed in the mutually matching portions of the pair
of flange parts; and
the paired mounting holes are formed such that the respective axes thereof are
2 0 inclined relative to the axes of the paired circular holes, and mutually approaching
forces are applied to the paired connecting arm parts in a direction inclined relative to
the axes of the circular holes by putting the paired flange parts nearer to each other up
to a dimension capable of fixing the end of the rotation shaft within the base part.
25 2. The yoke for a cross shaft universal joint according to Claim 1,
23
5
10
15
20
wherein
the axial direction of the axes of the paired mounting holes is inclined relative
to the axial direction of the axes of the paired circular holes .
. ''
3. The yoke .fm a cross shaft universal joint accbrding to Claim 1,
wherein,
when viewed from the. axial direction of the rotation shaft, the axial direction
of the axes of the paired mounting holes is inclined relative to the axial direction of the
axes of the paired circular holes.
• ; I
•; I
4. The yoke for a cross shaft universal joint according to Claims 2,
wherein
the discontinuous part is inclined relative to the axial direction of the base part
in such a manner that it crosses the axes of the paired mounting holes at right angles.
5. The yoke for a cross shaft universal joint according to any one of
Claims 1 to 4, wherein
the mounting hole formed in one of the paired flange parts is a through hole,
while the mounting hole formed in the other is a screw hole.