JP2001254755A - Universal joint yoke - Google Patents

Abstract

(57) [Problem] To provide a low cost and lightweight universal joint yoke with good overall strength balance. SOLUTION: On one end side, a cylindrical hole in which a shaft hole 5 into which a shaft is inserted is opened, a bolt hole for tightening and fixing with a bolt, and a slit 7 in the axial direction of the shaft.
A U-shaped arm 2 disposed at the other end and having a bearing hole 6 at the distal end for connecting to the other yoke, and the arm 2 and the tightening portion are integrated. A yoke of a universal joint formed by cold forging and machining, comprising:
The width L in a plane orthogonal to the axial direction of the bearing hole is a size obtained by adding (2.9 to 4.0) × 2 to the diameter of the bearing hole. Assuming that 1, the outer diameter M of the body and the width N of the tightening portion in the direction parallel to the axial direction of the bolt hole 9 are 0.95 to 1.07, and the outer diameter M of the body is 1 Then, the diameter of the shaft hole 5 is 0.6 to 0.76.
Is set to

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a yoke for a universal joint which is used for a steering device of an automobile and which is formed by cold forging and has a fastening portion for fastening and fixing a shaft. It is about.

[0002]

2. Description of the Related Art In general, in a steering apparatus for imparting a steering angle to a front wheel of an automobile, a movement of a steering shaft that rotates in accordance with an operation of a steering wheel is controlled by a cross-shaped universal joint (universal joint).
, And transmitted to the input shaft of the steering gear. In this universal joint, a pair of yokes are pivotally supported via a cross shaft.

The yoke constituting the universal joint is formed by a cold forging process. Cold forging is a processing method that can quickly produce a product having excellent dimensional accuracy, surface, and strength without generating debris. On the other hand, on the other hand, in addition to the requirement for a material to be used, which has few impurities and surface flaws, high ductility, and good dimensional accuracy, pre-treatments such as heat treatment and lubrication treatment are also required. Moreover, as for the mold to be used, a skilled technique and many years of experience are required for designing and manufacturing a mold capable of withstanding high pressure and abrasion.

Under these circumstances, there is a demand for a universal joint yoke which is further reduced in weight while maintaining the required strength. I have. Such a yoke is composed of a tightening portion for tightening bolts for mounting the shaft, and an arm portion having a bearing hole (bearing press-fitting hole). Are formed. In order to process the yoke having this configuration by cold forging, as shown in FIG. 9, an arm portion coarse material which is a cold forged coarse material obtained by forming an arm portion by upsetting from a preliminarily formed rough material. 42 is inserted into the die 32 of the press forging machine having the uneven thickness forming portion 33 for forming the uneven thickness portion only on one side, and the punch 36 is subjected to upsetting by applying a load to the tightening portion 25. Had been processed.

However, an uneven thickness portion is formed on one side surface of the tightening portion 25, and there is not much problem when the distance between the bearing hole and the tightening portion is small. In such a case, the uneven thickness portion is also extended accordingly, and as a result, the product weight increases, which is a problem in reducing the weight.

In the cold forging, since the forming of the tightening portion after the forming of the arm portion has the uneven thickness portion on only one side surface, the punch 36 is easily buckled when a load is applied. For example, as shown in FIG.
If the length of the tightening portion 25 of the rough material 42 to be subjected to the upsetting is L, in order to form the uneven thickness portion, L / d> 1.
In this state, the stress caused by the load (arrow) of the punch 36 cannot be dispersed, and the length L is set to one of the uneven thickness forming portions 33, as shown in FIG. There was a problem that the buckling 35 was caused and the molding was impossible.

Therefore, in Japanese Patent Publication No. 6-58124, as shown in FIG. 11, the tightening portion 11 has an uneven thickness portion 11c provided on one side surface of the end portion 11a opposite to the arm portion 24. And a body portion 11b provided at the end portion 11a in the direction of the arm portion 24, and a back portion opposite to the cutout 26 (see FIG. 12) provided at the uneven thickness portion 11c has a body portion. Since the projection 11d protrudes outward from the back outer surface 11f on the opposite side of the split of the portion 11b, even if the distance between the bearing hole 27 of the arm portion 24 and the fastening portion 11 is large, fastening by cold forging is performed. During the forming process of the portion 11, the uneven thickness portion 11c of the coarse material and the projection 11d side opposite to the uneven thickness portion 11c are both bulged outward and compressed, so that they do not buckle, and the uneven thickness portion 11c It is possible to mold into a shape with reduced surplus and excellent strength Good dimensional accuracy, weight reduction has been achieved, the yoke of the universal joint is disclosed. Note that the width of the arm portion 24 of this yoke (the width in the vertical direction in the figure) is
1b is smaller than the outer diameter, and as shown in FIG.
The outer diameter and the width of the uneven thickness portion 11c in the bolt axis direction are set to be equal.

[0008]

However, in the conventional yoke of the universal joint, the ratio of the width of the arm portion 24, the outer diameter of the body portion 11b, the width of the uneven thickness portion 11c, and the diameter of the serration hole 15 for inserting the shaft is reduced. It is not clear, the strength balance is poor depending on the set dimensions, and there is a case where the quality is partially excessive. For this reason, there is a problem that, in addition to the high cost of the material, the weight may increase due to the protrusion 11d and the like. Further, as shown in FIG. 12, the relief portion 24a at the tip of the arm portion 24 is difficult to be cold-formed, so that it has to be performed by machining, which increases the cost.

Accordingly, an object of the present invention is to solve the above-mentioned conventional problems and to provide a lightweight and low-cost universal joint yoke with good strength balance.

[0010]

In order to achieve the above object, according to the present invention, a bolt hole for tightening and fixing with a bolt is provided at a cylindrical portion where a shaft hole for inserting a shaft is opened at one end side. A U-shaped arm having, at its tip, a tightening portion having a split in the axial direction of the shaft, a bearing hole provided on the opposite side of the tightening portion, and connected to the other yoke; And a body portion integrally connecting the tightening portions, and in the yoke of the universal joint formed by cold forging and machining, the width of the arm portion in a plane orthogonal to the axial direction of the bearing hole. Is the size obtained by adding (2.9 to 4.0 mm) × 2 to the bearing hole diameter. When the width of the arm portion is 1, the outer diameter of the body portion and the tightening portion The width ratio in the direction parallel to the bolt hole axis direction is 0.95 to Assuming that the outer diameter of the body is 1.07 and the outer diameter of the trunk is 1, the shaft hole diameter is set to a ratio of 0.6 to 0.76. in this way,
By setting in consideration of the dimensional balance of each part of the yoke, the strength of each part can be balanced and the structure can be minimized, so that the weight can be reduced.

[0011]

An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a flat partial sectional view of a yoke of a universal joint according to a first embodiment of the present invention, FIG. 2 is a side view of FIG. 1 as viewed in the direction A, and FIG. 3 shows a universal joint in which a pair of yokes are connected. FIG. 4 is a side view, FIG. 4 is a sectional view taken along line BB of FIG. 1, and FIG.
FIG. 6 is a plan view of the yoke of the universal joint according to the second embodiment of the present invention, and FIG.
FIG. 8 is a sectional view taken along line EE in FIG. 6.

The universal joint in FIG. 3 is for connecting a steering shaft constituting a steering device of a vehicle, and has a structure in which a pair of yokes 1 and 12 are connected. The shaft 10 fixed to the yoke 1 is connected to the handle, and the shaft 22 fixed to the yoke 12 is connected to the steering gear.

The yoke 1 and the yoke 12 are rotatably connected to each other via a bearing (needle bearing) 15 by a spider (cross joint) 17 composed of two orthogonal shafts at the distal ends of the arms 2 and 23. ing. A resin thrust piece 18 is provided at the tip of the spider 17.
Is attached, and positions the spider 17 in the axial direction. The bearing 15 is attached to the arm portions 2 and 23 by press fitting into the bearing hole 6 and caulking 16. The spider 17 has a shaft diameter of about 10 mm. The shaft 10 is inserted into the tightening portion 4 of the yoke 1 and tightened and fixed by a bolt 11 via a washer 19. Similarly, a shaft 22 is fastened and fixed to the yoke 12 by the bolt 11.

As shown in FIGS. 1 and 2, the yoke 1 has a pair of arms 2 arranged to form a U-shape.
2 ', a tightening portion 4 on the other end side, and a body portion 3 which is a portion sandwiched between the arms 2, 2' and the tightening portions 4a, 4b. As a material for the yoke 1, JIS carbon steel for machine structure S10C to S38C is used.

In the vicinity of the tips of the pair of arms 2, 2 ',
Each has a bearing hole 6. The inner diameter of the bearing hole 6 is about 15 to 16 mm. The axial thickness P of the ends of the arms 2 and 2 'in the axial direction was about 3 to 4 mm, and the thickness Q in the direction orthogonal to the axial direction was about 2.9 to 4.0 mm. With this configuration, the rigidity around the bearing hole 6 becomes nearly uniform, the deformation during drilling is reduced, and the hole accuracy (cylindricity) is improved.
The width L of each of the arms 2 and 2 'in a plane orthogonal to the axial direction of the bearing hole 6 is determined by the inner diameter of the bearing hole 6 (2.9 to 4.
0 mm) × 2. Therefore, when the inner diameter of the bearing hole 6 is 16 mm, the arm width L is 21.8 to 24.
0 mm. As shown in FIG. 5, the escape 13 at the tip of the arm 2, 2 ′ is connected to the spider 17 (see FIG. 3) by the bearing hole 6.
The serration hole 5 is formed in a substantially circular arc shape centered on the axial center of the serration hole 5. Although not shown, the relief 13 may have a rectangular or elliptical shape. The chamfers 14, 14 provided on both side edges from the vicinity of the base end of the arm 2 'to the middle in the length direction are "reliefs" for increasing the bending angle of the universal joint. Of the chamfers 14,
The angle between the side surfaces of the arms 2 and 2 'is 28 to 36 degrees. The distance T between the arms 2, 2 'is about 41.5 mm.

The bolt holes 9 are opposed to the fastening portions 4a and 4b.
And screw holes 8 (see FIG. 4). The length from the center of the bearing hole 6 to the end face on the side of the fastening portion 4 is about 70.
mm. The bolt to be screwed into the screw hole 8 is JISB2
Use M8 of 05.

The body 3 is formed in a cylindrical shape having an opening at an end of the fastening portion 4 and having a serration hole (shaft hole) 5 for inserting a shaft 10 (see FIG. 3) therein. The inner diameter of the serration hole 5 is about 14.0 to 17.8 mm. As shown in FIG. 2, a slit 7 is provided in the axial direction of the shaft 10 from the fastening part 4 to the middle of the body part 3. The width of the slit 7 is 2 to 4 mm.

As shown in FIGS. 1, 2 and 4, when the arm width L is set to 1, the outer diameter M of the body 3 and the width N of the tightening portion 4 are set to a ratio of 0.95 to 1.07. . The ratio of the diameter of the serration hole 5 when the outer diameter M of the body 3 is set to 1 is 0.6 to 0.7.
6. By setting the outer diameter M of the body portion 3 and the width N of the tightening portion 4 to be approximately the same, and setting the length S of the tightening portion 4 to 20 mm, a spring washer for a bolt can be provided without providing a counterbore on the seat surface 20. (No. 8 of JIS B1251) can secure the seating surface, leading to low cost.

The screw holes 8 are formed by machining. The bolt holes 9, the serration holes 5, the slits 7, the end surfaces 21 of the fastening portions 4, the bearing holes 6, and the chamfered portions 14 are formed by machining or cold forming. Other parts are formed by cold forging. The relief 13 at the tip of the arm 2, 2 ′ is formed in a substantially arc shape, rectangular shape, or elliptical shape centered on the axial center of the serration hole 5, and can be formed by cold forging.

A number of experiments were conducted using the yoke 1 having the above-described configuration, and analysis was performed by the finite element method. As a result, the strength of each part was balanced and the bolt 1
By tightening No. 1, the shaft 10 could be securely tightened and fixed. Therefore, a light-weight yoke with a low material cost can be obtained. In addition, since the relief at the tip of the arms 2 and 2 'is formed in a substantially arc shape, rectangular shape, or elliptical shape, it can be formed by cold forging, which contributes to cost reduction.

Next, a second embodiment will be described with reference to FIGS.
This will be described with reference to FIG. 6, 7, and 8, this embodiment is substantially the same as the first embodiment, and the same portions are denoted by the same reference numerals. The difference is that
The fastening portion 34 of the yoke 31 is formed by rotating the fastening portion 4 of the yoke 1 in the first embodiment by 90 ° about the axis of the shaft 10.
The length of the shaft 10 in the axial direction also becomes shorter at the trunk 3,
This is a point slightly shorter than the yoke 1.

As in the first embodiment, the yoke 31 in this configuration is balanced in the strength of each part, and can contribute to weight reduction by the shortened body 3. The position of the tightening portion 24 in the rotational direction about the axis of the shaft 10 is not limited to the position shown in the first and second embodiments, but may be set to any position. However, as shown in FIG. 3, if the positions of the tightening portions of the yoke 1 and the yoke 12 are set in the same direction, the bolt tightening operation can be easily performed at the time of assembling and fixing to the vehicle.

[0023]

As described above, the width of a bearing hole of an arm in a plane perpendicular to the axial direction is set to a size obtained by adding (2.9 to 4.0 mm) × 2 to the diameter of the bearing hole. Assuming that the width of the bolt is 1, the ratio of the outer diameter of the body to the width of the tightening portion in the direction parallel to the axial direction of the bolt hole is 0.9.
Assuming that the outer diameter of the body is 1 and the shaft diameter is 0.6 to 0.76, the strength balance of each part of the yoke is sufficient while the shape is the minimum necessary. The shaft can be securely fastened and fixed by tightening the bolts. Therefore, it is possible to obtain a yoke that is sufficiently reduced in cost and weight.

[Brief description of the drawings]

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

FIG. 2 is a side view of the yoke shown in FIG.

FIG. 3 is a side view showing a universal joint connecting two yokes according to the first embodiment of the present invention.

FIG. 4 is a diagram showing a cross section taken along line BB of the yoke of FIG. 1;

FIG. 5 is a side view of the yoke of FIG. 1 viewed from the direction of arrow C;

FIG. 6 is a side view of a yoke of a universal joint according to a second embodiment of the present invention.

FIG. 7 is a partial cross-sectional view of the yoke of FIG.

FIG. 8 is a diagram showing a cross section taken along line EE of the yoke of FIG. 6;

FIG. 9 is an explanatory view showing a state in which a crude material of a conventional yoke is installed.

FIG. 10 is an explanatory view showing a buckling state of a conventional yoke.

FIG. 11 is a side view showing a conventional yoke.

FIG. 12 is an explanatory view showing escape at the tip of a conventional yoke.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Yoke 2 Arm part 3 Body part 4 Tightening part 5 Shaft hole (serration hole) 6 Bearing hole 7 Cutting 9 Bolt hole 10 Shaft

Claims (1)

[Claims] A shaft hole for inserting a shaft is opened at one end side, a bolt hole for tightening and fixing with a bolt, a tightening portion having a cut in an axial direction of the shaft, and A U-shaped arm portion having a bearing hole at the tip end for connecting to the other yoke, and a body portion integrally connecting the arm portion and the tightening portion; In the yoke of the universal joint formed by forging and machining, the width of the arm portion in a plane orthogonal to the axial direction of the bearing hole is obtained by adding (2.9 to 4.0 mm) × 2 to the bearing hole diameter. Assuming that the width of the arm portion is 1, the ratio of the outer diameter of the body portion to the width of the fastening portion in the direction parallel to the bolt hole axis direction is 0.95 to 1.95. 07 and the outer diameter of the body is 1, the shaft hole diameter is .6～
A yoke for a universal joint, wherein the yoke is set to a ratio of 0.76.