JP2000104750A - Universal joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a rattling occurrence in an axial direction of a spider and to reduce a bending torque by specifying a shape size and a material in a pin engaged with an axial hole of a cross shaft and projected from a shaft end. SOLUTION: In a state that a thrust piece 8 is inserted into an axial hole 65 of a spider 6, an end thereof is projected from a shaft portion 61 and is engaged with a bottom surface of a bearing cup 71. When press-inserting the cup 71, the piece 8 causes a compression elastic plastic deformation and retains an axial predetermined position by a previous pressure. The piece 8 is made of a polyacetal or polyamide resin and a convergent projection 82a is formed on an outer side of large diameter portions 82, 82 at both ends of a small diameter portion. When a length of the small diameter portion 81 of the piece 8 is 2.5-3.3 mm, a ratio of a sectional area and a length of the small diameter portion 81 is made to 1.7-2.4, and when the length is 3.3-4.1 mm, the ratio of the sectional area and the length is made to 1.5-2.2. Thereby, a rigidity of the small diameter portion 81 of the thrust piece 8 is appropriately adjusted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a universal joint used as a steering joint of an automobile.

[0002]

2. Description of the Related Art Japanese Utility Model Publication No. Hei 7-24661 discloses a universal joint in which a spider for connecting a pair of yokes constituting a universal joint is supported in a bearing hole of the yoke by using a bearing cup. I have. In this universal joint, a thrust piece is inserted into a center hole of a spider, the thrust piece is sandwiched between the bottom of the center hole and the bottom of a bearing cup, and a small diameter portion of the thrust piece is compression-plastically deformed. Thus, the spider can be held in the thrust direction in the bearing hole.

[0003]

However, in the above-mentioned universal joint, the performance as a steering joint or the like greatly changes due to the rigidity of the small diameter portion of the thrust piece after assembly, and the performance may not be sufficiently controlled.

For example, when the rigidity of the small diameter portion of the thrust piece is large, the bending torque of the universal joint becomes large, and when the thrust piece is used as a steering joint, the return of the steering wheel sometimes becomes poor. In severe cases, the bottom of the bearing cup was sometimes broken.

[0005] On the other hand, when the rigidity of the small diameter portion of the thrust piece is low, the thrust piece may be deformed by the load in the spider axial direction, and play may occur in the spider axial direction. As a result, the sealing performance deteriorated, and water sometimes entered the bearing.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a universal joint that does not generate backlash in the spider axial direction and has a small bending torque.

[0007]

In order to solve the above-mentioned problems, a universal joint according to the present invention is characterized in that cup-shaped bearings respectively fitted into bearing holes of opposed arms are used to adjust the shaft diameter portions at both ends of a cross shaft. While supporting rotatably around the direction,
A bottomed axial hole is provided at the shaft center of the cross shaft, and the bottom of the shaft hole is open at the end surface of the shaft diameter portion. A synthetic resin pin projecting from the end surface of the shaft diameter portion is fitted into the axial hole, and A universal joint that causes the pin to be plastically deformed by engaging the end of the pin with the cup bottom of the bearing to hold the shaft diameter portions at both ends of the cross shaft in the axial direction, wherein the pin is a shaft. Symmetrical with respect to a plane perpendicular to the direction, having large diameter portions slidable in the axial direction along the inner surface of the axial hole at both ends of the small diameter portion, and tapering outward from the large diameter portion. With the projection, the projection is engaged with the bottom of the cup of the bearing, and the material of the pin is any one of polyacetal resin and polyamide resin, and the length of the small diameter portion of the pin is 2.5 to
When it is less than 3.3 mm, the ratio between the cross-sectional area of the small diameter portion and the length of the small diameter portion is 1.7 to 2.4, and the length of the small diameter portion of the pin is 3.3 to 4.1 mm. In this case, the ratio between the cross-sectional area of the small diameter portion and the length of the small diameter portion is 1.5 to 2.2.

[0008] In the above universal joint, the pin has a large diameter portion slidable in the axial direction along the inner surface of the axial hole at both ends of the small diameter portion, symmetrical with respect to a plane perpendicular to the axial direction. ,
And, having a projection that tapers outward from the large diameter portion, the projection is engaged with the cup bottom of the bearing, and the material of the pin is one of a polyacetal resin and a polyamide resin, The length of the small diameter portion of the pin is 2.5 to
When it is less than 3.3 mm, the ratio between the cross-sectional area of the small diameter portion and the length of the small diameter portion is 1.7 to 2.4, and the length of the small diameter portion of the pin is 3.3 to 4.1 mm. In this case, since the ratio between the cross-sectional area of the small diameter portion and the length of the small diameter portion is 1.5 to 2.2,
The rigidity of the small diameter portion of the pin is appropriately adjusted. Therefore, it is possible to provide a universal joint that does not generate backlash in the cross-axis direction and has a small bending torque.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] FIG. 1 is a partial sectional view illustrating the structure of a universal joint according to a first embodiment.
The illustrated universal joint is for connecting a steering shaft constituting a steering device of a vehicle, and has a structure in which a pair of yokes 2 and 4 are connected. The shaft 1 extending from the yoke 2 is connected to the handle, and the shaft 5 extending from the yoke 4 is connected to the wheel.

One yoke 2 is connected to the other yoke 4 via a spider 6. One yoke 2
It is of a bolted type, and has a structure in which a base 21 fitted to the shaft 1 and a forked portion 22 for connecting to the spider 6 are integrally manufactured by press molding of a sheet metal. The other yoke 4 is of a welding fixed type, and has a structure in which a base 41 fitted to the shaft 5 and a forked portion 42 for connecting to the spider 6 are integrally manufactured by cold forging.

The fork portion 22 includes a pair of arms 22a and 22b extending in a shaft axis direction from a position facing the base portion 21.
Consists of A bearing hole 22c for holding a bearing is formed through the arm 22a, 22b at a position facing the tip of the arm 22a, 22b. The base 21 has a pair of tabs 21a, 21b.
Thereby, a U-shaped groove 21c having a substantially U-shaped cross section corresponding to the shape of the shaft 1 is formed. One tab 21a
Is formed with a nut hole 21d.
, A nut 11 is press-fitted and fixed. The other tab 21
b, a bolt hole 21e is formed.
A bolt (not shown) is inserted into e, and nut 11 is inserted.
Is concluded.

The fork portion 42 also has a pair of arms 42a, 42b extending in the shaft axis direction from a position facing the base portion 41.
Consists of A bearing hole 42c for holding a bearing is formed through the arm 42a, 42b at a position facing the distal end of the arm 42a, 42b. The base 41 has a through hole 41 extending in the axial direction.
c is formed in the through hole 41c.
Are fitted and fixed by welding.

FIG. 2 is a view for explaining the structure of the spider 6, and shows a cross section taken along the line AA of FIG. The spider 6 includes cylindrical shaft diameter portions 61, 61, 62, 62 extending in four directions around a main body 60. The pair of opposed shaft diameter portions 61, 61 are inserted into bearing holes 22c of the arms 22a, 22b in FIG. 1, and are supported by the cup-shaped bearing 7 so as to be rotatable around their axial directions. The pair of opposed shaft diameter portions 62, 62 are inserted into bearing holes 42c of the arms 42a, 42b in FIG. 1, and are supported by a cup-shaped bearing 107 so as to be rotatable around their axial directions. The end faces of the shaft diameter portions 61, 61, 62, and 62 are provided with bottomed axial holes 65 that open at these end faces.

Returning to FIG. 1, the bearing hole 22 of the arm 22a is
c is sealed by the bearing cup 71 in a state where the needle bearing 73 is arranged around the shaft diameter portion 61 of the spider 6. The bearing cup 71 is press-fitted into the bearing hole 22c, and is fixed to the arm 22a by caulking at an outer edge portion thereof. The inner end of the bearing cup 71 is in contact with the seal ring 75. This seal ring 75
The bearing 7 is sealed between the bearing cup 71 and the main body 60.

An axial hole 6 formed in the end face of the shaft diameter portion 61
5 is fitted with a thrust piece 8 which is a pin made of synthetic resin. This thrust piece 8 has an axial hole 65.
In this state, the end of the thrust piece 8 protrudes from the end face of the shaft diameter part 61 and engages with the bottom surface of the bearing cup 71. When the bearing cup 71 is press-fitted, the thrust piece 8 undergoes compression-elasto-plastic deformation, so that a preload toward the center in the axial direction is applied to the shaft diameter portions 61, 61 at both ends of the spider 6, and the thrust piece 8 is sandwiched between the arms 22a, 22b. The spider 6 can be held at a predetermined position in the axial direction.

Although detailed description is omitted, the arm 2
The bearing 7 of the arm 2a has the same structure as the bearing 7 of the arm 22a.
It has the same structure as the bearing 7 of FIG.

FIG. 3 is a view for explaining the structure of the thrust piece 8 incorporated in the universal joint of FIG. 1, and FIG. 4 is a cross-sectional view of the thrust piece 8 of FIG. The thrust piece 8 is made of a polyacetal resin or a polyamide resin, has a small-diameter portion 81 having a circular cross section at the center in the axial direction, and has large-diameter portions 82 at both ends. Outside the large diameter portion 82, a projection 82a formed of a tapered conical surface is formed. Further, four axially extending ridges 83 are formed on the outer surfaces of the large diameter portions 82, 82.
The axially outer end of each ridge 83 is drawn slightly inward from the edge of the outer peripheral end of the large diameter portion 82. In addition, each ridge 83
The inner end in the axial direction extends radially to the outer peripheral position of the small diameter portion 81 along a step surface formed on the small diameter portion 81 side of the large diameter portion 82. The large diameter portion 82 is formed in the axial hole 6 of the spider 6.
When the thrust piece 8 is inserted into the axial hole 65, the outer surface of the ridge 83 engages with the inner surface of the axial hole 6 so that the thrust piece 8 is inserted into the axial hole. At this time, the thrust piece 8 is slidable in the axial direction along the inner surface of the axial hole 6.
In the illustrated embodiment, the thrust piece 8 is symmetrical with respect to a predetermined plane perpendicular to the axial direction, and the same positional relationship is maintained regardless of which of the large-diameter portions 82, 82 is inserted into the axial hole 65. It is supposed to be.

Hereinafter, a specific embodiment of the thrust piece 8 will be described. The length E of the small diameter portion 81 of the thrust piece 8 was set to 3.3 to 4.1 mm (that is, 3.3 mm or more and 4.1 mm or less). Also, the cross-sectional area S of the small diameter portion 81
Is the sectional area S of the small diameter portion 81 with respect to the length E of the small diameter portion 81.
The ratio S / E was set to be 1.5 to 2.2.

FIG. 5 is a graph showing the relationship between the displacement ΔL, which is the amount of compression of the length L of the thrust piece 8, and the compression load applied to the thrust piece 8 in the axial direction. Here, the range R is a compression range of the thrust piece 8 determined by component accuracy, assembly accuracy, and the like. Note that, on the vertical axis, the value W1
Is the minimum thrust load required when used as a steering joint, and the value W2 is the maximum load within a range where the bending torque does not increase and the return of the steering wheel does not deteriorate. As is clear from the graph, it can be seen that a universal joint having a small bending torque, no play in the axial direction, and a good sealing property can be obtained.

[Second Embodiment] Hereinafter, a universal joint according to a second embodiment will be described. The universal joint of the second embodiment includes:
This is a modified example of the universal joint of the first embodiment, and the same portions are denoted by the same reference numerals and redundant description will be omitted.

FIG. 6 is a partial sectional view illustrating the structure of the universal joint according to the second embodiment. In the universal joint of the second embodiment, the shape of the thrust piece 208 is different from that of the first embodiment.

FIG. 7 is a view for explaining the structure of the thrust piece 208, and FIG.
2 shows a cross section taken along line CC of FIG. The thrust piece 208 is made of a polyacetal resin or a polyamide resin, has a small diameter portion 281 at the center in the axial direction, and has a large diameter portion 28 at both ends.
2,282. Outside the large diameter portion 282, a projection 282a formed of a tapered conical surface is formed.
The large diameter portion 282 has an outer diameter substantially equal to the inner diameter of the axial hole 65 of the spider 6 but slightly larger. Therefore,
When the thrust piece 208 is inserted into the axial hole 65, the thrust piece 208 is retained in the axial hole 65,
It is slidable in the axial direction along the inner surface of the axial hole 65.

With the universal joint of the second embodiment, the same characteristics as in FIG. 5 were obtained. That is, since an appropriate compressive stress acts on the thrust piece 208, a universal joint having a small bending torque, no play in the axial direction, and a good sealing property is obtained.

Third Embodiment A universal joint according to a third embodiment will be described below. The universal joint of the third embodiment also
It is a modification of the universal joint of the first embodiment.

FIG. 9 is a partial sectional view illustrating the structure of the universal joint according to the third embodiment. In the universal joint of the third embodiment, the shape of the thrust piece 308 and the shape of the axial hole 365 are different from those of the first embodiment.

FIG. 10 is a view for explaining the structure of the thrust piece 308. FIG. 11 is a cross-sectional view of the thrust piece 308 of FIG. Thrust piece 308
Is made of polyacetal resin or polyamide resin, has a small-diameter portion 381 at the center in the axial direction, and has large-diameter portions 382, 382 at both ends. Outside the large diameter portion 382, a projection 382a formed of a tapered conical surface is formed. Four projecting ridges 383 extending in the axial direction are formed on the outer surfaces of the large diameter portions 382, 382 and the small diameter portion 381. The large diameter portion 382 has an outer diameter slightly smaller than the inner diameter of the axial hole 365 of the spider 6, and
8 is inserted into the axial hole 365, the outer surface of the ridge 383 engages with the inner surface of the axial hole 306, and the thrust piece 30
8 is held in the axial hole 365,
Is slidable in the axial direction along the inner surface.

Hereinafter, a specific embodiment of the thrust piece 308 will be described. Small diameter part 3 of thrust piece 308
The length E ′ of 81 was 2.5 to less than 3.3 mm (that is, 2.5 mm or more and less than 3.3 mm). The sectional area S (including the ridge 383) of the small diameter portion 381 is
The ratio S ′ of the sectional area S ′ of the small diameter portion 81 to the length E ′ of 1
/ E 'was adjusted to be 1.7 to 2.4. As a result, the universal joint of the third embodiment also obtained the same characteristics as those in FIG. That is, a universal joint having a small bending torque, no play in the axial direction, and a good sealing property was obtained.

[Fourth Embodiment] Hereinafter, a universal joint according to a fourth embodiment will be described. The universal joint according to the fourth embodiment includes:
It is a modification of the universal joint of the first embodiment or the second embodiment. In the universal joint of the fourth embodiment, the thrust piece 40
8 is different from that of the first embodiment.

FIG. 12 is a view for explaining the structure of the thrust piece 408, and FIG. 13 is a cross-sectional view of the thrust piece 408 of FIG. Thrust piece 408
Is made of a polyacetal resin or a polyamide resin, has a substantially quadrangular prism-shaped small-diameter portion 481 at the center in the axial direction, and has large-diameter portions 482 and 482 at both ends. This large diameter part 4
82, a projection 482a formed of a tapered conical surface
Are formed. Four protrusions 483 extending in the axial direction are formed on the outer surface of each of the large-diameter portions 482, 482. The inner end in the axial direction of each protrusion 483 extends radially to the outer peripheral position of the small-diameter portion 481 along a step surface formed on the small-diameter portion 481 side of the large-diameter portion 482. Thrust piece 4
08 into the axial hole of the spider,
The outer surface of the thrust piece 4 is engaged with the inner surface of the axial hole.
08 is slidably held in the axial hole.

The thrust piece 4 shown in FIGS. 12 and 13
In the universal joint of the fourth embodiment incorporating the 08, the same characteristics as those in FIG. 5 were obtained. That is, the thrust piece 408
Since an appropriate compressive stress is applied to the universal joint, a universal joint having a small bending torque, no play in the axial direction, and a good sealing property is obtained.

[0031]

As is apparent from the above description, according to the universal joint of the present invention, the material of the pin is one of a polyacetal resin and a polyamide resin, and the length of the small diameter portion of the pin is 2 0.5 to less than 3.3 mm,
The ratio between the cross-sectional area of the small diameter portion and the length of the small diameter portion is 1.7 to 2.4.
And the length of the small diameter portion of the pin is 3.3 to 4.1 mm.
In this case, since the ratio between the cross-sectional area of the small diameter portion and the length of the small diameter portion is 1.5 to 2.2, the rigidity of the small diameter portion of the pin is appropriately adjusted. Therefore, no backlash occurs in the cross-axis direction,
Moreover, a universal joint having a small bending torque can be provided.

[Brief description of the drawings]

FIG. 1 is a front view of a universal joint according to a first embodiment of the present invention.

FIG. 2 is a perspective view of the spider AA constituting the universal joint of FIG. 1;
It is arrow sectional drawing.

FIG. 3 is a view illustrating the shape of a thrust piece incorporated in the universal joint of FIG. 1;

FIG. 4 is a sectional view taken along line BB of FIG. 3;

FIG. 5 is a diagram illustrating characteristics of the universal joint according to the first embodiment.

FIG. 6 is a front view of a universal joint according to a second embodiment.

FIG. 7 is a view illustrating the shape of a thrust piece incorporated in the universal joint of FIG. 6;

FIG. 8 is a sectional view taken along the line CC of FIG. 7;

FIG. 9 is a front view of a universal joint according to a third embodiment.

FIG. 10 is a view illustrating the shape of a thrust piece incorporated in the universal joint of FIG. 9;

FIG. 11 is a sectional view taken along line DD of FIG. 10;

FIG. 12 is a diagram illustrating a shape of a thrust piece incorporated in a universal joint according to a fourth embodiment.

FIG. 13 is a sectional view taken along the line FF of FIG. 12;

[Explanation of symbols]

 Reference Signs List 1 shaft 2, 4 yoke 5 shaft 6 spider 7 bearing 8 thrust piece 21 base 22 fork 22a, 22b arm 22c bearing hole 41 base 42 fork 42a, 42b arm 42c bearing hole 60 main body 61, 62 shaft diameter 65 axial direction Hole 71 Bearing cup 73 Needle bearing 75 Seal ring 81 Small diameter part 82 Large diameter part 82a Projection 83 Projection

Claims (1)

[Claims] A cross-shaped bearing which is fitted in a bearing hole of an opposing arm supports shaft diameter portions at both ends of a cross shaft so as to be rotatable around an axial direction, and is provided on a shaft center of the cross shaft. A bottomed axial hole that is open at the end face of the shaft diameter portion is provided, and a synthetic resin pin protruding from the end face of the shaft diameter portion is fitted into the axial hole, and the end of the pin is inserted into the bearing. A universal joint that causes the pin to undergo plastic deformation by engaging with a cup bottom to hold axial diameter portions at both ends of the cross shaft in the axial direction, wherein the pin is symmetrical with respect to a plane perpendicular to the axial direction. In the form, having large diameter portions slidable in the axial direction along the inner surface of the axial hole at both ends of the small diameter portion, and having a projection tapering outward from the large diameter portion, The protrusion is engaged with the cup bottom of the bearing, and the material of the pin is polyacetal tree And are either the polyamide resin, when the length of the small diameter portion of the pin is less than 2.5～3.3Mm, the ratio of the length of the cross-sectional area and the small diameter portion of the small-diameter portion 1.7
And the length of the small diameter portion of the pin is 3.3 to 3.3.
A universal joint, wherein the ratio of the cross-sectional area of the small-diameter portion to the length of the small-diameter portion is 1.5 to 2.2 when the diameter is 4.1 mm.