JP2016023799A - Yoke for universal joint and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure which can easily perform a layout for securing rigidity, related to a yoke 8g in which large hoop stress is generated at a surface layer part of a pressure-insertion hole part 21 of a coupling hole 14a accompanied by the pressure-insertion of an end part of a shaft into the coupling hole 14a, and a stress concentration based on torsion at a single-side opening peripheral part of the coupling hole 14a is generated at the transmission of torque.SOLUTION: The pressure-insertion hole part 21 into which the end part of the shaft is pressure-inserted is formed at an intermediate part or the other end part in an axial direction out of the coupling hole 14a, and a non-pressure insertion hole part 22 which is larger than the pressure-insertion part 21 in diameter, and into which the end part of the shaft is not pressure-inserted is formed at a single end part in the axial direction.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an improvement in a yoke that constitutes a cross-shaft universal joint (cardan joint) for connecting torques between rotating shafts constituting a steering device, and a method for manufacturing the yoke.

  The steering apparatus for an automobile is configured as shown in FIG. The movement of the steering wheel 1 operated by the driver is transmitted to the input shaft 6 of the steering gear unit 5 via the steering shaft 2, the universal joint 3a, the intermediate shaft 4, and another universal joint 3b. Then, a pair of left and right tie rods 7 and 7 are pushed and pulled by a rack and pinion mechanism built in the steering gear unit 5, and an appropriate rudder corresponding to the operation amount of the steering wheel 1 is applied to the pair of left and right steering wheels. It is configured to give corners.

  As the two universal joints 3a and 3b incorporated in such a steering apparatus, generally, a cross shaft type universal joint called a cardan joint as illustrated in FIG. 9 is widely used. Each of these universal joints 3a and 3b includes a pair of yokes 8a and 8b (8c and 8d), and a cross shaft 9 that pivotably connects the tip portions of both yokes 8a and 8b (8c and 8d). Is provided. The base portion of one of the yokes 8 a (8 c) is connected to the rear end portion of the male shaft 10 (the front end portion of the female shaft 11, which is a hollow shaft), which is the solid shaft constituting the intermediate shaft 4. The base portion of the yoke 8b (8d) is coupled and fixed to the front end portion (rear end portion of the input shaft 6) of the steering shaft 2 so that torque can be transmitted. The intermediate shaft 4 is formed by combining the male shaft 10 and the female shaft 11 so that torque can be transmitted and relative displacement in the axial direction can be achieved.

  FIG. 10 shows a first example of a conventional structure of a yoke called a vertical insertion type that can be used as one of the yokes 8a and 8c constituting the universal joints 3a and 3b. The yoke 8e shown in FIG. 10 is, as described in Patent Document 1 and the like, widely known from the past, by subjecting a metal plate material such as a steel plate to press working including punching and bending, or It is made integrally by forging and punching a metal material such as a steel round bar. Such a yoke 8e includes a base portion 12 and a pair of arm portions 13 and 13. Of these, the base 12 is formed in a substantially annular shape, and has a coupling hole 14 formed in the axial direction (vertical direction in FIG. 10) at the center in the radial direction. The coupling hole 14 is a circular hole whose inner peripheral surface is a simple cylindrical surface, or a serration hole formed by forming female serrations on the inner peripheral surface of such a circular hole. The arms 13 and 13 are provided so as to extend from two positions on the opposite side in the radial direction of the base 12 to one axial side (upper side in FIG. 10). Concentric circular holes 15 and 15 are formed at the distal ends of the arms 13 and 13, respectively. In a state where the cross shaft type universal joint is assembled, the bottomed cylindrical bearing cups 16 and 16 (see FIG. 9) are fitted and fixed in the circular holes 15 and 15, respectively. At the same time, the ends of the cross shaft 9 (see FIG. 9) are rotatably supported in the bearing cups 16 and 16 via a plurality of needles 17 and 17, respectively. Further, the inner side surfaces of the arms 13 and 13 facing each other and the one side surface of the base portion 12 in the axial direction are smoothly continuous by concave curved surfaces, respectively.

When the end portion of the shaft 18 formed in a columnar shape or a circular tube shape such as an intermediate shaft is coupled to the base portion 12 of the yoke 8e as described above, first, the end portion of the shaft 18 is connected to the base portion 12. Is press-fitted into the coupling hole 14 (inserted by interference fit). When the coupling hole 14 is a serration hole, male serration is formed on the outer peripheral surface of the end portion of the shaft 18. Then, with the press-fitting, the male serration is engaged with the serration hole with an allowance. Next, welding is performed on a corner portion between the other axial side surface of the base portion 12 (the lower side surface in FIG. 10) and the outer peripheral surface of the shaft 18, so that a weld metal 19 is passed between these both surfaces. . As a result, the end of the shaft 18 is coupled and fixed to the base 12 of the yoke 8e so that torque can be transmitted.

  FIG. 11 shows a second example of a conventional structure of a vertically inserted yoke. In the case of the yoke 8f of the second example of this conventional structure, in the peripheral portion of the base portion 12a around the other end portion in the axial direction of the coupling hole 14, and in the peripheral portion near the other end portion in the axial direction of the coupling hole 14. An overhang ring portion 20 having a smaller radial thickness is provided. The projecting ring portion 20 and the shaft 18 are welded in a state where the weld metal 19 is spanned between the outer circumferential surface and the front end surface of the projecting ring portion 20 and the outer circumferential surface of the shaft 18.

  In the case of the second example having such a conventional structure, when the above-described welding is performed, the overhanging ring portion 20 can be intensively heated (the heat applied to the overhanging ring portion 20 is transferred to the base portion. 12a can be made difficult to disperse to the axially intermediate portion side). For this reason, it is possible to increase the amount of penetration of the outer peripheral surface and the front end surface of the projecting ring portion 20, and accordingly, it is easy to ensure the strength of the welded portion.

  In the case of each conventional structure described above, the entire coupling hole 14 is a press-fitting hole for press-fitting the end of the shaft 18. A large hoop stress (circumferential tensile stress) is generated in the surface layer portion of the coupling hole 14 as the end portion of the shaft 18 is press-fitted. On the other hand, one end opening peripheral portion (P portion in FIGS. 10 and 11) of the coupling hole 14, which is a continuous portion between one axial side surface of the base 12 (12 a) and the inner peripheral surface of the coupling hole 14, When torque is transmitted in a state where the cross shaft universal joint is assembled, stress concentration due to torsion occurs. That is, in each of the above-described conventional structures, a large hoop stress due to the press-fitting and a stress concentration based on the torsion are generated at the peripheral edge of the one end opening of the coupling hole 14 so as to overlap each other. The value increases. Therefore, it becomes difficult to design the base 12 (12a) for securing the strength.

JP 2013-24369 A

  In view of the above-described circumstances, the present invention generates a large hoop stress in the surface layer portion of the press-fitting hole portion of the coupling hole and presses the end portion of the shaft into the coupling hole, and transmits torque. Invented to realize a structure that can easily design for securing strength and a method of manufacturing the same for a universal joint yoke in which stress concentration due to torsion occurs at the peripheral edge of one end opening of the coupling hole It is.

Of the universal joint yoke and the manufacturing method thereof according to the present invention, the universal joint yoke described in claim 1 includes a base portion and a pair of arm portions.
Of these, the base is an annular portion, and has a coupling hole formed in the axial direction at the center in the radial direction.
Further, the both arm portions are provided in a state of extending from one position on the opposite side in the radial direction of the base portion to one axial direction.
In particular, in the case of the universal joint yoke according to claim 1, the coupling hole is a press-fitting hole portion for press-fitting at least the axial intermediate portion of the axial intermediate portion to the other end portion and the end portion of the shaft. In addition, the one axial end adjacent to the press-fitting hole in the axial direction is a non-press-fit hole that is larger in diameter than the press-fitting hole and into which the end of the shaft is not press-fitted.

When implementing the universal joint yoke of the present invention, preferably, as in the invention described in claim 2, the continuous portion between the inner peripheral surface of the non-press-fit hole portion and one axial side surface of the base portion, Provide a chamfer.
In this case, preferably, the chamfered portion is formed by pressing as in the invention described in claim 3.

Further, when the universal joint yoke of the present invention is implemented, preferably, as in the invention described in claim 4, in the base portion, in the peripheral portion of the other axial end portion of the coupling hole. An overhanging ring portion having a smaller radial thickness than the peripheral portion near the other end in the axial direction of the coupling hole is provided.
When the base of the universal joint yoke of the present invention and the end of the shaft are coupled, the end of the shaft is press-fitted into the coupling hole, and if necessary, the outer peripheral surface of the shaft and the overhang These shafts and the projecting ring portion are welded in a state where the weld metal is spanned between the outer peripheral surface and the tip end surface of the ring portion.

  According to a fifth aspect of the present invention, there is provided a universal joint yoke manufacturing method according to the fourth aspect of the present invention, wherein the universal joint yoke manufacturing method is the non-press-fit hole in the outer peripheral surface of the tip portion. A press die having a non-press-fit hole processing surface that is a processing surface that matches the portion is prepared, and an intermediate having a substantially disk-like or substantially cylindrical base meat portion for forming the base portion Get the material. After that, by pushing the tip of the pressing die into the inside of the base meat part from the central part of the axial side surface of the base meat part, the non-press-fit hole of the pressed part A portion aligned with the processing surface for the part is used as the non-press-fit hole portion, and a central portion of the other side surface in the axial direction of the meat portion for the base portion is bulged in the axial direction, and the bulged portion is referred to as the protruding portion. A meat part for an overhanging ring part for forming the ring part.

  Further, when the universal joint yoke manufacturing method described in claim 5 is performed and the manufacturing object is the universal joint yoke described in claim 4 quoting claim 3, As in the invention described in claim 6, a chamfered portion processing surface that is a processing surface that matches the chamfered portion in addition to the non-press-fit hole processed surface on the outer peripheral surface of the tip portion of the press die. Can be provided. And, from the center part of the axial direction one side surface of the base meat part constituting the intermediate material, by pushing the tip of the press mold into the base meat part, The portion that matches the processed surface for the non-pressed hole portion can be the non-pressed hole portion, and the portion that matches the processed surface for the chamfered portion can be the chamfered portion.

  That is, in the present invention, the method for manufacturing a universal joint yoke according to claim 6 is the method for manufacturing a universal joint yoke according to claim 4, which refers to the above-mentioned claim 3, wherein A press die having a processed surface for a non-pressed hole portion that is a processed surface that matches the non-pressed hole portion and a processed surface for a chamfered portion that is a processed surface that matches the chamfered portion is prepared on the surface. At the same time, an intermediate material having a substantially disk-like or substantially columnar base portion for forming the base portion is obtained. After that, by pushing the tip of the pressing die into the inside of the base meat part from the central part of the axial side surface of the base meat part, the non-press-fit hole of the pressed part The portion that matches the processing surface for the part is the non-press-fit hole portion, and the portion that matches the processing surface for the chamfered portion is the chamfered portion, and the central portion of the other side surface in the axial direction of the meat portion for the base portion The bulging portion is bulged in the axial direction, and the bulged portion is used as a bulging ring portion meat portion for forming the bulging ring portion.

In the case of the universal joint yoke according to the first aspect of the present invention, the portion of the press-fitting hole portion of the coupling hole is a portion where a large hoop stress is generated when the end of the shaft is press-fitted into the coupling hole. The inner peripheral surface of the non-press-fit hole portion of the coupling hole and one axial side surface of the base portion, which are portions where stress concentration due to torsion occurs when torque is transmitted in a state where the surface layer portion and the cross shaft universal joint are assembled And the continuous portion (peripheral edge portion of one end of the coupling hole) are located at positions separated from each other. Therefore, in the case of the present invention, as in each of the conventional structures described above, compared to a structure in which a portion where a large hoop stress due to the press-fitting occurs and a portion where stress concentration due to the twist occurs overlap each other, The maximum value of stress generated in the base can be kept low. As a result, the design for securing the strength of the base can be easily performed.

According to the universal joint yoke described in claim 2, since the chamfered portion is provided in the continuous portion between the inner peripheral surface of the non-press-fit hole portion of the coupling hole and one side surface in the axial direction of the base portion, It is possible to alleviate the stress concentration due to the twist generated in the part. Therefore, the maximum value of the stress generated in the base portion can be further reduced. As a result, the design for securing the strength of the base can be performed more easily.
According to the universal joint yoke described in claim 3, since the chamfered portion is formed by press working, compressive residual stress can be applied to the surface layer portion of the continuous portion. Therefore, the allowable stress of this continuous part can be improved. As a result, the design for securing the strength of the base portion can be performed more easily.

  Further, in the case of the universal joint yoke described in claim 4, when the base portion is coupled to the end portion of the shaft, the end portion of the shaft is press-fitted into the coupling hole, and the outer peripheral surface of the shaft is projected. If these shafts and overhanging rings are welded in a state where weld metal is stretched between the outer peripheral surface and the front end surface of the ring portion, the overhanging ring portion will be heated intensively during this welding. (The heat applied to the overhanging ring portion can be hardly dispersed on the intermediate side in the axial direction of the base portion). For this reason, it is possible to increase the amount of penetration of the outer peripheral surface and the front end surface of the projecting ring portion, and it is easy to secure the strength of the welded portion accordingly.

  According to the method for manufacturing a universal joint yoke according to claim 5 of the present invention, the base material is pressed from the central portion of one axial side surface of the base portion meat portion into the base portion meat portion. By pushing the tip of the metal mold, a non-press-fit hole portion and a protruding ring portion meat portion for forming the protruding ring portion can be formed simultaneously. For this reason, the manufacturing cost of the universal joint yoke can be suppressed.

  According to the method for manufacturing a universal joint yoke according to claim 6 of the present invention, from the central part of one axial side surface of the base part meat part of the intermediate material, the inside of the base part meat part is pressed. By pushing the front end of the mold, the non-press-fit hole portion and the chamfered portion and the overhang ring portion meat portion for forming the overhang ring portion can be formed at the same time. For this reason, the manufacturing cost of the universal joint yoke can be suppressed.

The perspective view of the yoke which shows the 1st example of embodiment of this invention. Similarly, the cross-sectional views (B) and (B) of the yoke viewed from above (A) and (C) viewed from below (B). The a section enlarged view of (B) of FIG. Sectional drawing which shows one example of the manufacturing method of a yoke in order of a process. Sectional drawing for demonstrating the process of obtaining the intermediate material shown to (B) from the intermediate material shown to (A) of FIG. The fragmentary sectional view shown in the state which fixedly fixed the end of the shaft to the base of the yoke. The figure similar to FIG. 3 which shows another example of the shape of the chamfering part employable when implementing this invention. The partially cut side view which shows an example of the steering apparatus known conventionally. The partial cutting side view of the intermediate shaft which couple | bonded the conventional cross-shaft type universal joint provided with the vertical insertion type yoke to the both ends. The fragmentary sectional view shown in the state where the end of the shaft was coupled and fixed to the base of the yoke of the first example of the conventional structure. The figure similar to FIG. 10 regarding the yoke of the said 2nd example. The principal part expanded sectional view which shows the modification of embodiment of this invention.

  1 to 6 show an example of an embodiment of the present invention corresponding to claims 1 to 4 and 6. The feature of this example is mainly the structure of the coupling hole 14a provided in the central portion in the radial direction of the base portion 12b and the manufacturing method of the yoke 8g provided with such a coupling hole 14a. Including the point that an overhanging ring portion 20 is provided at the center of the other side surface in the axial direction of the base portion 12b, the structure and operation of other portions are shown in FIG. Since it is the same as that in the case of the second example of the conventional structure, the overlapping description will be omitted or simplified, and the following description will focus on the features of this example. In the following description, with respect to the axial direction of the yoke 8g (and its intermediate material), one side means the upper side in each of FIGS. 1 and 2B and FIGS. The side refers to the lower side in these drawings.

  In the case of the yoke 8g of this example, the coupling hole 14a has a press-fitting hole portion 21 for press-fitting the end portion of the shaft 18 at the axially intermediate portion or the other end portion. At the same time, one axial end adjacent to the press-fit hole 21 in the axial direction is a non-press-fit hole 22 having a larger diameter than the press-fit hole 21 and into which the end of the shaft 18 is not press-fit. Both the hole portions 21 and 22 are provided concentrically with each other, and an annular step surface 23 is provided between the axial edges of the both hole portions 21 and 22. The press-fitting hole 21 is a circular hole or a serration hole similar to the coupling hole 14 constituting the yoke 8f of the second example of the conventional structure shown in FIG. On the other hand, the non-press-fit hole portion 22 is a circular hole whose inner peripheral surface is a simple cylindrical surface. Further, such an inner peripheral surface of the non-press-fit hole portion 22 and one axial side surface of the base portion 12b (a concave curved surface that smoothly connects the one axial side surface and the inner side surfaces of the pair of arms 13 and 13). 3), an R chamfer 24 having a partial arc shape in cross section is provided over the entire circumference as shown in FIG. In particular, in the case of this example, the R chamfered portion 24 is formed by press working.

  Next, a manufacturing method of the yoke 8g of this example having the above-described configuration will be described. When manufacturing this yoke 8g, first, by subjecting a metal plate material such as a steel plate to press working including punching and bending, or by subjecting a metal material such as a steel round bar to forging. As shown in FIG. 4A, a first intermediate material 25 is obtained. The first intermediate material 25 has a substantially disk-like or substantially columnar base meat part 26 for forming the base part 12b, and a shaft from two positions on the opposite side in the radial direction of the base part meat part 26. A pair of arm portions meat portions 27 and 27 each having a substantially rectangular plate shape are provided to form the both arm portions 13 and 13 provided in a state extending in one direction.

If such a first intermediate material 25 is obtained, then, from the central part on one side surface in the axial direction of the base meat part 26 to the inside of the base meat part 26, as shown in FIG. The tip of the mold 28 is pushed in. The front end surface of the pressing die 28 is a circular plane perpendicular to the axial direction, and the outer diameter side portion of the front end surface is a step which is a machining surface that matches the step surface 23. It is a surface machining surface 29. Further, the outer peripheral surface of the tip end portion of the pressing mold 28 matches the processing surface 30 for the non-pressing hole portion which is the processing surface that matches the inner peripheral surface of the non-pressing hole portion 22 and the R chamfered portion 24. It is the processing surface 31 for R chamfered portions that is the processing surface to be processed. The stepped surface 29 and the non-press-fit hole portion processed surface 30 are smoothly continuous with a convex curved surface having a partial arc shape. Then, as described above, by pushing the tip of such a pressing die 28 from the center of one side surface in the axial direction of the base meat portion 26 into the base meat portion 26, The center part of one side surface in the axial direction of the base meat part 26 is recessed, and the recessed part (the part where the tip part of the pressing die 28 is pushed) is aligned with the processing surface 29 for the stepped surface. The portion to be aligned is the stepped surface 23, the portion that is aligned with the non-press-fit hole portion machining surface 30 is the non-press-fit hole portion 22, and the portion that is aligned with the R-chamfered portion machining surface 31 is the R-chamfer portion 24. To do. At the same time, the central portion of the other side surface in the axial direction of the base portion meat portion 26 is bulged in the axial direction, and the bulged portion is used to form the bulged ring portion 20. 32 is a second intermediate material 33 as shown in FIG.

  If such a second intermediate material 33 is obtained, then a punching process or a cutting process (this press-fitting hole portion 21 is used as a serration hole in the central portion of the base meat portion 26 constituting the second intermediate material 33. In this case, the press-fitting hole portion 21 is formed by further performing broaching for forming female serrations, and with the formation of such a press-fitting hole portion 21, By removing the central portion of the meat portion 32, the projecting ring portion 20 is formed, and by punching or cutting the tip portions of the both-arm portion meat portions 27, 27, the circular holes 15 are formed. , 15 are formed, and further post-processing is performed as necessary to complete the yoke 8g as shown in FIG.

  When the end portion of the shaft 18 is coupled to the base portion 12b of the yoke 8g as described above, as shown in FIG. 6, first, the end portion of the shaft 18 is connected to the press-fit hole portion 21 of the coupling hole 14a. Press fit into. When the press-fitting hole portion 21 is a serration hole, a male serration is formed on the outer peripheral surface of the end portion of the shaft 18, and the male serration is engaged with the serration hole with a tightening margin with the press-fitting. Let Next, the projecting ring portion 20 and the shaft 18 are welded in a state where the weld metal 19 is passed between the outer circumferential surface and the front end surface of the projecting ring portion 20 and the outer circumferential surface of the shaft 18.

  In the case of the universal joint yoke of this example configured as described above, the press-fitting of the coupling hole 14a is a portion where a large hoop stress is generated when the end of the shaft 18 is press-fitted into the coupling hole 14a. A surface layer portion of the hole portion 21, and an inner peripheral surface of the non-press-fit hole portion 22 of the coupling hole 14a, which is a portion where stress concentration due to torsion occurs when torque is transmitted in a state where the cross shaft universal joint is assembled. A continuous portion (a portion where the R chamfered portion 24 is provided) with one side surface in the axial direction of the base portion 12b exists at a position away from each other. Therefore, in the case of this example, as in each of the conventional structures described above, compared to a structure in which a portion where a large hoop stress due to the press-fitting occurs and a portion where stress concentration due to the twist occurs overlap each other, The maximum value of stress generated in the base 12b can be kept low. As a result, the design for securing the strength of the base portion 12b can be easily performed.

  In the case of this example, since the R chamfered portion 24 is provided in a continuous portion between the inner peripheral surface of the non-press-fit hole portion 22 and one side surface in the axial direction of the base portion 12b, it occurs in this continuous portion. The stress concentration due to the twist can be alleviated. Furthermore, in the case of this example, the R chamfered portion 24 is formed by press working. For this reason, compressive residual stress can be given to the surface layer portion of the continuous portion. The compressive residual stress has an action of suppressing the occurrence of damage such as a crack based on the stress applied during use, and therefore the allowable stress of the continuous portion can be improved. As a result, the design for securing the strength of the base 12b can be performed more easily.

  Further, in the case of this example, the distal end portion of the pressing die 28 extends from the central portion on one side surface in the axial direction of the base meat portion 26 of the first intermediate material 25 to the inside of the base meat portion 26. The stepped surface 23, the non-press-fit hole portion 22, the R chamfered portion 24, and the protruding ring portion meat portion 32 can be formed simultaneously. For this reason, the manufacturing cost of the universal joint yoke can be suppressed.

[Modification of Embodiment]
FIG. 12 shows a modification of the embodiment of the present invention. In this modification, the conical hole 40 which is a stress relief part is provided at the end of the shaft 18 on the yoke 8e side without providing the non-press-fit hole 22 in the yoke 8e.
Also with this conical hole 40, the maximum value of the stress generated at the base of the yoke 8 e can be kept low as with the non-press-fit hole 22.
In this modification, the example in which the present invention is applied to the universal joint yoke using the yoke 8e not provided with the overhanging ring portion is shown. However, the universal joint using the yoke 8g provided with the overhanging ring portion is shown. It can also be applied to the yoke.
Further, the coupling hole 14 may be a serration hole instead of a circular hole. In this case, male serrations are formed on the outer peripheral surface of the end portion of the shaft 18.

When practicing the present invention, it is not always necessary to provide a chamfered portion at a continuous portion between the inner peripheral surface of the non-press-fit hole portion of the coupling hole and one axial side surface of the base portion.
Further, when this chamfered portion is provided, the chamfered portion can be a C chamfered portion 34 having a linear cross-sectional shape as shown in FIG.
In the present invention, when the universal joint yoke manufacturing method according to claim 5 is carried out, for example, for a press having a shape in which the processing surface 31 for the R chamfered portion of the press die 28 is omitted. Using the mold, the non-press-fit hole portion 22 and the protruding ring portion meat portion 32 are simultaneously formed by the same method as in the above-described embodiment. Thereafter, when the chamfered portion is provided in the continuous portion, the chamfered portion is formed in a separate process by press working using another pressing die or by cutting.
Further, when the present invention is carried out, it is not always necessary to use the projecting ring portion as a portion for passing the weld metal between the shaft and the portion for simply securing the axial length of the coupling hole. Just use as.
Moreover, when implementing this invention, the axial direction other end part of the said joint hole can also be made into a non-press-fit rear part instead of a press-fit hole part.

DESCRIPTION OF SYMBOLS 1 Steering wheel 2 Steering shaft 3a, 3b Universal joint 4 Intermediate shaft 5 Steering gear unit 6 Input shaft 7 Tie rod 8a-8g Yoke 9 Cross shaft 10 Male shaft 11 Female shaft 12, 12a, 12b Base portion 13 Arm portion 14, 14a Joint hole DESCRIPTION OF SYMBOLS 15 Circular hole 16 Bearing cup 17 Needle 18 Shaft 19 Weld metal 20 Overhang | projection ring part 21 Press-fit hole part 22 Non press-fit hole part 23 Step surface 24 R chamfer part 25 First intermediate material 26 Meat part for base part 27 Meat part for arm part 28 Die for pressing 29 Processing surface for stepped surface 30 Processing surface for non-press-fit hole portion 31 Processing surface for R chamfered portion 32 Meat portion for overhanging annular portion 33 Second intermediate material 34 C Chamfered portion 40 Conical hole (stress relief portion)

Claims (6)

An annular base portion having a coupling hole formed in the axial direction at the center in the radial direction;
A universal joint yoke comprising a pair of arm portions provided in a state extending from two positions on the opposite side in the radial direction of the base portion to one axial direction;
The coupling hole has at least an axially intermediate portion of the axially intermediate portion or the other end portion as a press-fit hole portion for press-fitting an end portion of the shaft, and is adjacent to the press-fit hole portion in the axial direction. The universal joint yoke is characterized in that the one end portion in the axial direction is a non-press-fit hole portion having a larger diameter than the press-fit hole portion and into which the end portion of the shaft is not press-fitted.   The universal joint yoke according to claim 1, wherein a chamfered portion is provided at a continuous portion between an inner peripheral surface of the non-press-fit hole portion and one axial side surface of the base portion.   The universal joint yoke according to claim 2, wherein the chamfered portion is formed by press working.   Of the base portion, a protruding ring portion having a smaller radial thickness than the peripheral portion near the other axial end portion of the coupling hole is provided around the other axial end portion of the coupling hole. The universal joint yoke according to any one of claims 1 to 3. A method for manufacturing a universal joint yoke according to claim 4,
Prepare a pressing mold having a non-press-fit hole working surface that is a work surface that matches the non-press-fit hole portion on the outer peripheral surface of the tip, and form a substantially disk or circle to form the base. After obtaining an intermediate material having a columnar base meat part, the tip of the pressing mold is pushed into the base meat part from the central part of one axial side surface of the base meat part. Thus, of the pushed-in portion, the portion that matches the processing surface for the non-press-fit hole portion is used as the non-press-fit hole portion, and the central portion of the other side surface in the axial direction of the base portion meat portion is bulged in the axial direction. And let this bulged part be a protruding ring part meat part for forming the protruding ring part,
Manufacturing method of universal joint yoke. The manufacturing object is the universal joint yoke according to claim 4, which cites claim 3.
In addition to the non-press-fit hole processing surface, a chamfered portion processing surface that is a processing surface that matches the chamfered portion is provided on the outer peripheral surface of the tip portion of the press die,
From the central part of the axial side surface of the base meat part constituting the intermediate material, by pushing the tip of the pressing die into the base meat part, The portion that matches the processed surface for non-press-fit holes is the non-press-fit hole portion, and the portion that matches the processed surface for chamfered portions is the chamfered portion,
A method for manufacturing a universal joint yoke according to claim 5.