JP6160183B2 - Cross shaft universal joint and method of manufacturing cross shaft universal joint - Google Patents

Description

  The present invention relates to a cross shaft universal joint used in a steering device, a method for manufacturing a cross shaft universal joint, a crimping jig used for manufacturing a cross shaft universal joint, and an intermediate for a steering device including a cross shaft universal joint. The present invention relates to a steering device including a shaft and a cross shaft type universal joint.

  Conventionally, there has been a cross shaft type universal joint that is connected with a cross shaft between a pair of yokes and transmits torque from one yoke to the other yoke while allowing a relative angle change of the pair of yokes. It is used for an intermediate shaft of a steering device.

  Such a cross shaft type universal joint includes a bearing cup that is disposed in a through hole formed in the yoke and covers the end of the cross shaft, and a sliding bush is interposed between the bearing cup and the cross shaft. What prevents the bearing cup and the like from coming out of the yoke by providing a caulking portion that protrudes from a part of the through hole portion into the hole and makes contact with the bottom portion of the bearing cup while facilitating relative rotation of the shaft and the yoke. Yes (see Patent Document 1).

  In addition, by interposing a needle bearing having a bearing cup that covers the end of the cross shaft between the cross shaft and the yoke, the cross shaft and the yoke are easily rotated relative to each other, and a hole is formed from a part of the through hole portion. There is one that prevents the bearing cup from coming out of the yoke by providing a crimping portion that protrudes inward and contacts the bottom of the bearing cup (see Patent Document 2).

US Pat. No. 3,733,668 Japanese Patent Application No. 5-66741

  However, in the conventional cruciform universal joint, since the caulking portion is formed so as to press the bearing cup against the cruciform shaft, the contact pressure between the bottom of the bearing cup and the tip of the cruciform shaft increases, resulting in friction. By increasing the force, the relative rotation between the cross shaft and the yoke was increased. If the relative rotation between the cross shaft and the yoke becomes heavy, the operating torque of the cross shaft universal joint increases, and the steering performance for the vehicle may adversely affect the return performance of the steering wheel.

  Although it is possible to provide a minute gap so that the bottom of the bearing cup and the tip of the cross shaft do not contact each other, the assembly is not good because the parts are small, and the cross shaft and the bearing cup move relative to each other. May also occur. The play is a factor that deteriorates the steering feeling in the vehicle steering apparatus. Further, when using a needle bearing, it is possible to perform backlashing by closing the clearance around the needle. However, the operating torque of the cross shaft universal joint also increases due to the backlashing. There is a risk of adversely affecting the return performance of the handle.

  As described above, in the cross shaft universal joint, there is a contradiction that the operating torque of the cross shaft universal joint increases when attempting to prevent backlash, and the backlash tends to occur when attempting to reduce the operating torque. It has been difficult to achieve both a reduction in operating torque and a reduction in operating torque.

  In view of such a problem, the present invention provides a cross shaft universal joint, a method for manufacturing a cross shaft universal joint, and a cross shaft universal joint for preventing an excessive increase in operating torque while suppressing backlash. An object of the present invention is to provide a caulking jig, an intermediate shaft for a steering device, and a steering device that have good steering feeling and ensure steering return performance after steering.

In order to solve the above problems, in the present invention,
A pair of yokes each having a bifurcated tip, and a through hole at each of the opposed positions of the bifurcated tip;
A bearing cup having a substantially bottomed cylindrical shape, the bottom portion of the bearing cup being directed to the outside of the bifurcated tip portion, and the through-hole portion being formed at a position where the bottom portion is recessed from the outer surface of the tip portion; Bearings press-fitted into each of the
Four tip portions are fitted into each of the bearings, and include a cross shaft for connecting the pair of yokes,
In the cruciform universal joint formed with a caulking portion projecting into the hole from the through hole portion around the concave portion,
The cross shaft and the bottom of the bearing cup are in contact,
The caulking portion is provided by a plurality in the circumferential direction of the distant, I the bottom and contactless der, there is a predetermined gap between said bottom and said caulked portion,
The bearing has a plurality of needles arranged in a circumferential direction in a single row, and at least one end surface of the needle is separated from the bearing cup,
It is assumed that the insertion portion of the cross shaft is inserted with an intermediate fit over the entire length of the bearing .

This prevents backlash that occurs when there is a gap between the bottom of the bearing cup and the cross shaft, while preventing the contact pressure between the bottom of the bearing cup and the tip of the cross shaft from increasing, and operating torque. A small cross shaft type universal joint can be provided. If the caulking part does not press the bearing cup, the caulking part and the bottom part may be in contact with each other. In addition, it is possible to prevent the occurrence of looseness caused by the clearance generated between the side surface of the cross shaft and the bearing. Further, even if the bearing cup comes into contact with the caulking portion due to an external impact or the like, the bearing becomes difficult to tilt, and the bearing can be prevented from tilting with respect to the cross shaft.

  Preferably, the bearing is a shell-type needle bearing.

  Accordingly, it is possible to provide a high allowable load and a high allowable rotational speed while reducing the radial dimension of the bearing, and the mounting of the bearing is facilitated. The “shell needle bearing” refers to a bearing in which an outer ring is formed from a thin plate material and a plurality of needle rollers are arranged inside the outer ring.

  Preferably, a convex portion protruding toward the cross axis is formed at the bottom center.

  Thereby, the dimension of the radial direction of the contact part of the said bottom part and the said cross shaft can be made small, and the rotational resistance which arises by the friction of the said contact part can be made small.

In order to solve the above problems, in the present invention, in the method for manufacturing the above-described cross shaft universal joint,
Forming a portion of the yoke that forms the crimped portion in a planar shape;
A caulking jig that forms the caulking portion is provided with a stopper that abuts against the yoke surface when the caulking portion is caulked to a predetermined depth that is not in contact with the bottom portion, corresponding to the depth of the recess.
The caulking jig is pressed against the planar portion of the yoke, and the caulking is finished when the stopper comes into contact with the yoke.

  Thereby, the non-contact of a crimping part and a bottom part can be ensured easily and reliably, and the operating torque of a cross-shaft type universal joint can be reduced.

Further, in order to solve the above problems, in the present invention, in the caulking jig used for manufacturing the above-described cross shaft type universal joint,
A stopper that contacts the yoke surface when the crimped portion is crimped to a predetermined depth not in contact with the bottom portion is provided.

  With this caulking jig, non-contact between the caulking portion and the bottom portion can be ensured easily and reliably, and the operating torque of the cross shaft universal joint can be reduced.

  In order to solve the above problems, in the present invention, it is assumed that the intermediate shaft for a steering device includes the cross shaft type universal joint.

  As a result, the steering device including the intermediate shaft prevents rattling, provides good steering feeling, reduces the operating torque of the cruciform universal joint, and ensures steering return performance after steering. The “intermediate shaft for a steering device” refers to a shaft-like member disposed in a steering torque transmission path in a steering device used in a vehicle or the like.

  In order to solve the above problems, in the present invention, it is assumed that the steering device includes the intermediate shaft for the steering device.

  As a result, the steering device prevents rattling, provides good steering feeling, reduces the operating torque of the cruciform universal joint, and ensures steering return performance after steering.

  According to the present invention, a cross shaft universal joint that prevents the operating torque from becoming excessively large while suppressing backlash, a method of manufacturing a cross shaft universal joint, a crimping jig for a cross shaft universal joint, and It is possible to provide an intermediate shaft for a steering device and a steering device that have good steering feeling and ensure steering return performance after steering.

It is a perspective view which shows the steering device for vehicles provided with the cross-axis type universal joint which concerns on embodiment of this application. It is a figure which shows the plane and cross section of the intermediate shaft for steering apparatuses for vehicles provided with the cross-axis-type universal joint which concerns on embodiment of this application. It is a figure which shows the plane and cross section of the cross-shaft type universal joint which concerns on embodiment of this application. It is an expanded sectional view showing a yoke and a needle bearing of a cross shaft type universal joint according to an embodiment of the present application. It is a flowchart which shows the manufacturing method of the cross-shaft type universal joint which concerns on embodiment of this application. It is a figure which shows the formation method of the crimp part of the cross-shaft type universal joint which concerns on embodiment of this application. (A) is sectional drawing which shows a mode that a crimping part is formed, (b) is an enlarged bottom view of a crimping jig.

  A cross shaft type universal joint according to an embodiment of the present application will be described with reference to FIGS. FIG. 1 is a perspective view showing a vehicle steering apparatus 1 having a cross shaft type universal joint according to an embodiment of the present application.

  As shown in FIG. 1, a vehicle steering apparatus 1 including a cross shaft type universal joint according to an embodiment of the present application includes a steering wheel 2, a steering shaft (not shown) that transmits a steering torque from the steering wheel 2, A steering column 3 that rotatably supports the steering shaft, an electric motor 4 that is attached to the steering column 3 and assists steering, an intermediate shaft 5 that is connected to the steering shaft and transmits steering torque, and a pinion that is connected to the intermediate shaft 5 Steering gear 7 that houses a shaft 6 and a rack shaft (not shown) that reciprocates in the axial direction as the pinion shaft 6 rotates, and tie rods 8a and 8b that transmit the axial force of the rack shaft to the steering wheel to steer the steering wheel. And have.

  FIG. 2 is a view showing a plane and a cross section of the intermediate shaft 5. The boundary between the plane and the cross section is indicated by a two-dot chain line. As shown in FIG. 2, the intermediate shaft 5 has a male shaft 9 disposed on the vehicle rear side (right side as viewed in FIG. 2) and a vehicle front side (left side as viewed in FIG. 2). The vehicle rear side of the female shaft 10 is fitted on the front side of the vehicle so as to be able to transmit steering torque and to be relatively movable in the axial direction.

  A yoke 11a having a bifurcated tip is formed at the vehicle rear side end of the male shaft 9, and the yoke 11a further has a cross shaft 12 on a yoke 11b having a bifurcated tip disposed on the vehicle rear side. To form a cross shaft universal joint 13 according to the present embodiment. The yoke 11b is connected to the steering shaft. The yoke 11a and the yoke 11b can be formed from a metal material such as iron or aluminum using a manufacturing method such as forging, casting, or sheet metal processing.

  A yoke 14a having a bifurcated tip is also formed on the vehicle front side of the female shaft 10, and the yoke 14a is further connected to a yoke 14b disposed on the vehicle front side via a cross shaft 15 to form a cross shaft type. A universal joint 16 is configured. The yoke 14b is connected to the pinion shaft 6 shown in FIG.

  FIG. 3 is a view showing a plane and a cross section of the cross shaft type universal joint 13 according to the embodiment of the present application. The boundary between the plane and the cross section is indicated by a two-dot chain line. The yokes 11a and 11b face each other with their bifurcated tip portions shifted from each other by 90 °, and through-holes 17a, 17b, 17c and 17d (17c and 17d are not shown) are formed at the bifurcated tip portions, The ends of the cross shaft 12 are inserted into the through holes 17a to 17d, respectively.

  Needle bearings 18a, 18b, 18c, and 18d (18d not shown) are interposed between the peripheral wall surfaces of the through holes 17a to 17d and the corresponding tips of the cross shaft 12. Four caulking portions 19 for restricting the movement of the needle bearings 18a to 18d are formed at the edge portions of the through holes 17a to 17d, respectively.

  FIG. 4 is an enlarged cross-sectional view showing the yoke 11a and the needle bearing 18a. The needle bearing 18a is disposed with the bottom of the bearing cup 20 facing away from the rotation center axis of the yoke 11a (outside of the yoke 11a), and the bottom of the bearing cup 20 extends from the outer surface of the yoke 11a (upper surface in FIG. 4). It arrange | positions in the recessed position and forms the recessed part.

  The caulking portion 19 is formed so that the edge of the through hole 17a is deformed by caulking to protrude into the hole of the through hole 17a, restricts the movement of the needle bearing 18a, and the needle bearing 18a comes out of the yoke 11a. Is preventing. The needle bearing 18a is press-fitted into the through-hole 17a, and movement is limited by the press-fitting, but a double safety structure is provided by providing a crimping portion 19. In the present embodiment, four crimping portions 19 are formed at positions opposed in the radial direction (see FIG. 3).

  The needle bearing 18a is a full-roller shell needle bearing having no retainer and formed from a bearing cup 20 having a substantially bottomed cylindrical shape and a plurality of needles 21 arranged inside the bearing cup 20. . The bearing cup 20 has a convex portion 22 that protrudes toward the cross shaft 12 at the center of the bottom, and the convex portion 22 is in contact with the end surface of the cross shaft 12. When the convex portion 22 and the cross shaft 12 are in contact with each other, it is possible to prevent backlash caused by interference between the bearing cup 20 and the end surface of the cross shaft 12. Although the entire end surface of the cross shaft 12 may be in contact with the bottom of the bearing cup 20, the projection 22 is provided to reduce the radial dimension of the contact portion between the bottom of the bearing cup 20 and the cross shaft 12. Thus, the rotational resistance due to friction in the relative rotation between the cross shaft 12 and the bearing cup 20 can be reduced.

  The opening-side end 23 of the bearing cup 20 is so narrow that it does not come into contact with the cross shaft 12, thereby preventing foreign matter from entering the bearing cup 20. The bearing cup 20 is preferably formed by drawing a steel plate and then heat-treating to harden the surface and improving the durability of the inner raceway surface on which the needle 21 rolls.

  As described above, since the cross shaft 12 is fitted into the needle bearing 18a with an intermediate fit, the needle 21 is assembled in a substantially zero gap in the radial direction of the cross shaft 12 (left and right direction in FIG. 4). However, in the axial direction of the cross shaft 12 (vertical direction in FIG. 4), only the upper portion is in contact with the bottom surface of the bearing cup 20, and the lower portion is provided with a gap between the opening side end portion 23 of the bearing cup 20. The needle 21 can move in the axial direction of the cross shaft 12 within the gap. As described above, since a plurality of crimping portions 19 are provided at distant positions on the circumference, even if the needle bearing 18a moves in the axial direction and contacts the crimping portion 19, the needle bearing 18a is inclined. Therefore, the gap between the needle and the inner peripheral surface of the bearing cup 20 can be kept substantially zero.

  The caulking portion 19 is disposed with a gap between the bearing cup 20 and the caulking portion 19 and the bearing cup 20 are not in contact with each other. As a result, the bearing cup 20 is not pressed toward the cross shaft 12 by the caulking portion, and the contact pressure between the bottom of the bearing cup 20 and the tip of the cross shaft 12 does not increase. The relative rotation with the cross shaft 12 does not become excessively heavy. Further, since excessive preload can be prevented, durability of the bearing can be improved. In particular, when the needle 21 is constrained with substantially zero gap as described above, the fluctuation of the operating torque due to the caulking becomes remarkable, so that the effect is further exerted. The handle is good and the handle can be returned well. The caulking portion 19 and the bearing cup 20 may be in contact with each other as long as the bottom portion of the bearing cup 20 is not pressed against the tip portion of the cross shaft 12, but the bottom portion of the bearing cup 20 is provided by providing a gap as described above. Can be reliably prevented from being pressed against the tip of the cross shaft 12.

  FIG. 5 is a diagram illustrating a method of manufacturing the cross shaft universal joint 13 according to the embodiment of the present application. In the manufacture of the cross shaft type universal joint 13 according to the embodiment of the present application, first, the cross shaft 12, the yokes 11a and 11b, the needle bearings 18a to 18d, and the caulking jig 24 are prepared (S1), and a holding tool (not shown) is prepared. Is used to arrange the end of the cross shaft 12 in the through holes 17a and 17c formed in the yoke 11a with the center thereof aligned (S2). Then, the needle bearings 18a and 18c are press-fitted from the outer side of the yoke 11a to the inner side (from the upper side to the lower side in FIG. 4) to predetermined positions using a bearing press-fitting device (not shown) (S3). As shown in FIG. 4, the cross shaft 12 has a chamfered finish on the outer peripheral portion of the tip, and the needle 21 also has a chamfered finish on the outer peripheral portion of the end, so that the needle bearings 18 a and 18 c and the cross Even if a slight misalignment occurs between the bearing 12 and the bearing 12, it can be press-fitted. Thereafter, similarly to the yoke 11a, the tip of the cross shaft 12 is arranged in the through holes 17b and 17d formed in the yoke 11b (S4), and the needle bearings 18b and 18d are press-fitted to a predetermined position. (S5). Finally, the crimping portion 19 is formed using the crimping jig 24, and the process ends (S6).

  FIG. 6 is a diagram illustrating a method for forming the crimped portion 19 of the cross shaft universal joint 13 according to the embodiment of the present application. (A) is sectional drawing which shows a mode that the crimping | crimped part 19 is formed. FIG. 4B is an enlarged bottom view of the crimping jig 24. FIG. The crimping portion 19 is formed using a crimping jig 24. The caulking jig 24 has a protrusion 25 and a stopper 26 formed at the lower end.

  The crimping portion 19 is formed by pressing the projection 25 of the crimping jig 24 against a predetermined location on the periphery of the through hole 17a of the yoke 11a. The formation of each crimping portion 19 ends when the stopper 26 of the crimping jig 24 comes into contact with the surface of the yoke 11a. Thereby, a clearance gap can be reliably provided between the crimping part 19 and the bearing cup 20 of the needle bearing 18a, and the raise of the operating torque of a cross-shaft type universal joint can be suppressed stably. The other needle bearings 18b, 18c, and 18d can similarly form the crimped portion 19. Also, the cross shaft universal joint 16 on the front side of the vehicle shown in FIG. 2 (left side as viewed in FIG. 2) can be manufactured in the same manner as the cross shaft universal joint 13 according to this embodiment.

  While the present invention has been described with reference to specific embodiments, the present invention is not limited to this, and various improvements and modifications can be made.

  For example, the bearing is not limited to a full-roller-type shell needle bearing without a cage, and a shell-type needle bearing having a cage, a solid needle bearing, a ball bearing, a roller bearing, a slide bearing, or the like can be used.

  Further, the bearing and the cross shaft are not limited to an intermediate fit, but can also be a clearance fit or an interference fit.

  The shape of the crimping portion is not limited to that shown in the above embodiment, and may be formed, for example, over the entire circumference of the through hole. Further, the number of crimping portions can be changed as appropriate, and can be one or a plurality of locations. Accordingly, the shape of the crimping jig can be changed.

  The convex portion formed at the bottom of the bearing cup may be attached to a disc-shaped component formed separately from the bearing cup, or may not be provided depending on the operating torque.

  In order to prevent foreign matter from entering the bearing cup, a seal covering the gap between the cross shaft and the bearing cup may be provided.

  The arrangement of the yoke and the cross shaft and the press-fitting of the needle bearing may be performed first on the side of the yoke 11b, and the press-fitting of the needle bearing is not performed after the press-fitting of all the needle bearings is completed. The crimped portion may be formed from the point where the process is completed.

  As described above, according to the present invention, the cross-shaft universal joint and the method for manufacturing the cross-shaft universal joint that prevent the operating torque from becoming excessively large while suppressing backlash, and the steering feeling are good. It is possible to provide an intermediate shaft for a steering device and a steering device that ensure the steering wheel return performance after steering.

DESCRIPTION OF SYMBOLS 1 Vehicle steering device 2 Steering wheel 3 Steering column 4 Electric motor 5 Intermediate shaft 6 Pinion shaft 7 Steering gear 8a, 8b Tie rod 9 Male shaft 10 Female shaft 11a, 11b, 14a, 14b Yoke 12, 15 Cross shaft 13, 16 Cross Shaft type universal joints 17a, 17b, 17c, 17d Through holes 18a, 18b, 18c, 18d Needle bearing 19 Caulking portion 20 Bearing cup 21 Needle 22 Protruding portion 23 Opening side end portion 24 Caulking jig 25 Protrusion 26 Stopper

Claims (7)

A pair of yokes each having a bifurcated tip, and a through hole at each of the opposed positions of the bifurcated tip;
A bearing cup having a substantially bottomed cylindrical shape, the bottom portion of the bearing cup being directed to the outside of the bifurcated tip portion, and the through-hole portion at a position where the bottom portion is recessed from the outer surface of the tip portion; Bearings press-fitted into each of the
Four tip portions are fitted into each of the bearings, and include a cross shaft for connecting the pair of yokes,
In the cruciform universal joint formed with a caulking portion projecting into the hole from the through hole portion around the concave portion,
The cross shaft and the bottom of the bearing cup are in contact,
The caulking portion is provided by a plurality in the circumferential direction of the distant, I the bottom and contactless der, there is a predetermined gap between said bottom and said caulked portion,
The bearing has a plurality of needles arranged in a circumferential direction in a single row, and at least one end surface of the needle is separated from the bearing cup,
The fitting portion of the cross shaft, the cross shaft type universal joint, characterized that you have been fitted in fit intermediate entire length relative to the bearing.   The cross shaft type universal joint according to claim 1, wherein the bearing is a shell type needle bearing. The cross shaft type universal joint according to claim 1 or 2 , wherein a convex portion protruding toward the cross shaft is formed at the center of the bottom portion. In the manufacturing method of the cross-shaft type universal joint of any one of Claim 1 thru | or 3 ,
Forming a portion of the yoke that forms the crimped portion in a planar shape;
A caulking jig that forms the caulking portion is provided with a stopper that abuts against the yoke surface when the caulking portion is caulked to a predetermined depth that is not in contact with the bottom portion, corresponding to the depth of the recess.
A method of manufacturing a cross shaft type universal joint, wherein the caulking jig is pressed against the planar portion of the yoke, and the caulking is terminated when the stopper comes into contact with the yoke. In the caulking jig used for manufacture of the cross shaft type universal joint according to any one of claims 1 to 3 ,
A crimping jig for a cross shaft type joint, comprising: a stopper that comes into contact with the surface of the yoke when the caulking portion is caulked to a predetermined depth not in contact with the bottom portion. An intermediate shaft for a steering apparatus, comprising the cross shaft universal joint according to any one of claims 1 to 3 . A steering apparatus comprising the intermediate shaft for a steering apparatus according to claim 6 .

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