JP2017003085A - Universal joint and steering device including universal joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a universal joint having sufficient shaft holding force of a yoke, preventing abnormal wear and fracture of teeth of a female serration, and superior in durability, and a steering device having the universal joint.SOLUTION: In a universal joint, a yoke 20 is provided with a cylindrical connection portion 30 which has a female serration 38 engaged with a male serration 54 formed on an outer peripheral face of an output shaft 7, on an inner peripheral face and to which the output shaft 7 is inserted, and the connection portion 30 has a pair of thick portions 40, 40 forming a slit 42, and is connected to the output shaft 7 by deforming the pair of thick portions 40, 40 in directions to be close to each other by a fastening bolt 45. The female serration 38 has a first circumferential range on which a plurality of teeth 39 are formed at equal pitches, and a second circumferential range on which a plurality of teeth 39 are formed at pitches larger than the pitches of the teeth 39 of the first circumferential range at a slit 42 side with respect to the first circumferential range.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a universal joint used in a steering apparatus and the like, and a steering apparatus including the universal joint.

  2. Description of the Related Art Conventionally, in a vehicular electric power steering apparatus or the like, a universal joint in which a fitting portion with a shaft member is serrated to couple the shaft members so as to transmit torque, and is coupled to the shaft member by a bolt tightening force. Is used.

5 (a) and 5 (b) are cross-sectional views showing a coupling structure between a yoke 120 and a shaft member in a conventional universal joint used in an electric power steering device for a vehicle. FIG. Shows a state before fastening bolt tightening, and FIG. 5B shows a state after fastening bolt fastening.
As shown in FIG. 5A, in the conventional universal joint, the plurality of teeth 155 of the male serration 154 of the shaft member 107 are formed at equal pitches in the circumferential direction. The plurality of teeth 139 of the female serration 138 of the yoke 120 are also formed on the circumference at equal intervals, that is, at an equal pitch. The male serration 154 of the shaft member 107 and the female serration 138 of the yoke 120 are concentric with the shaft member 107 and the yoke 120 before the fastening bolt (not shown) inserted through the bolt insertion hole 144 is tightened. When arranged, the gap between the male serration 154 and the female serration 138 is formed so as to be constant over the entire circumference in the circumferential direction, as shown in FIG.

  When tightening the fastening bolt, the yoke 120 is less likely to deform at the bolt insertion hole 144 side, that is, the slit 142 side portion (the range indicated by the double-headed arrow A in FIG. 5B) than the central axis C of the female serration 138. Since the portion opposite to the slit 142 from the axis C (the range indicated by the double-headed arrow B in FIG. 5B) is easily deformed, the yoke 120 deforms unevenly as the fastening bolts are tightened. Therefore, in the state where the tightening of the fastening bolt is completed, the teeth 155 of the male serration 154 and the teeth 139 of the female serration 138 are opposite to the slit 142 across the central axis C as shown in FIG. , And a position near the fastening bolt insertion hole 144, but not at a position facing the extending direction of the bolt insertion hole 144 across the central axis C, and the teeth 155 of the male serration 154 and the female serration A gap S remains between the teeth 139 of 138.

  When the fastening bolts are completely tightened, the portion of the female serration 138 in the vicinity of the slit 142, that is, the portion of the female serration 138 in the range indicated by the circle in FIG. 5B is on the contact surface with the male serration 154. A high surface pressure is generated locally. That is, a portion having a high average stress is generated on the contact surface between the teeth 139 of the female serration 138 and the teeth 155 of the male serration 154. In the portion of the female serration 138 having a high average stress, abnormal wear of the teeth 139 of the female serration 138 occurs locally or the teeth 139 are damaged due to repeated torque input, that is, the stress amplitude by the subsequent steering operation.

  In order to prevent such abnormal wear of the teeth 139 of the female serration 138 and breakage of the teeth 139, Patent Documents 1 and 2 describe a female serration formation region and a female serration on the inner peripheral surface of the shaft member fitting hole of the yoke. The universal joint provided with the non-formation area | region, ie, a missing-tooth part, is disclosed.

  Patent Document 3 discloses a first male serration in which an output shaft, which is a shaft member, is fitted into a shaft member fitting hole portion on the bottom side of the tightening bolt, and a shaft member on the opening side of the tightening bolt. A universal joint is disclosed that has a second male serration that fits into a portion of the fitting hole, and in which the first male serration module is formed larger than the second male serration module.

JP 2012-193798 A Japanese Utility Model Publication No. 52-169641 JP 2012-96681 A

  As in Patent Documents 1 and 2, by providing a missing tooth portion in which female serrations are not formed, abnormal wear and breakage of the female serration teeth can be prevented, but as in Patent Documents 1 and 2 above. If the missing tooth portion is provided over the entire axial length of the shaft member fitting hole, the number of teeth meshing with the male serration of the shaft member is reduced as a whole yoke. As a result, the tangential force generated per tooth of the female serration during torque transmission is greater than when no missing teeth are provided, and there is a risk that the wear of the female serration teeth meshing with the shaft member will be accelerated. is there.

  Further, according to Patent Document 3, the first male serration that fits into the shaft member fitting hole portion on the bottom side of the fastening bolt and the shaft member fitting hole portion on the opening side of the fastening bolt are fitted. Both mating second male serrations can be tightly meshed with the corresponding female serrations. However, since the male serration of the steering shaft is generally formed by rolling, the male serration is ensured by making the male serration uniform in the axial direction. In other words, if the shape of the male serration tooth is different in the axial direction, the processing stress acting on each portion of the tooth having a different shape during the rolling process will be different. As a result, the accuracy of the rolling process is lowered, and the yoke may not be able to obtain a desired shaft holding force with respect to the output shaft in a coupled state with the output shaft.

  The present invention has been made in view of such a situation, and the universal joint having excellent durability performance, the yoke having sufficient shaft holding force, preventing abnormal wear and breakage of the teeth of the female serration, and It is an object of the present invention to provide a steering device having a universal joint.

  In order to solve the above-described problems, a universal joint according to the present invention includes a cross shaft and a pair of yokes connected via the cross shaft, and the pair of yokes is formed on an outer peripheral surface of the shaft member. Female serrations meshing with the male serrations are formed on the inner peripheral surface, each of which includes a cylindrical connecting portion into which the shaft member is inserted, and at least one of the pair of yokes is connected to the inner peripheral surface from the outer peripheral surface. A pair of facing portions that form a slit extending in the radial direction to the surface and extending in the axial direction, and freely coupled to the shaft member by deforming the pair of facing portions toward each other by a screw member In the joint, the female serration includes a first circumferential range in which a plurality of teeth are formed at an equal pitch on the side opposite to the slit with respect to a central axis of the coupling portion, and the first circumferential range. At the slit side, characterized in that it has a second circumferential extent which a plurality of teeth at a pitch larger than the pitch of the plurality of teeth of said first circumferential range is formed.

  In a preferred aspect of the present invention, the plurality of teeth in the second circumferential range are formed such that the pitch gradually increases as the teeth approach the slit.

  In a preferred aspect of the present invention, the plurality of teeth in the second circumferential range are formed at an equal pitch.

  In a preferred aspect of the present invention, the second circumferential range is at least a half of the circumferential range of the female serration on the slit side with respect to the central axis of the connecting portion. .

  In a preferred aspect of the present invention, the male serration and the female are arranged when the shaft member and the connecting portion are arranged concentrically before the pair of opposing portions are deformed in a direction approaching each other by the screw member. The gap with the serration is gradually increased from the portion on the side facing the slit with respect to the central axis of the connecting portion toward the slit.

  In a preferred aspect of the present invention, the plurality of teeth of the female serration are in mesh with the plurality of teeth of the male serration in a state where the connecting portion and the shaft member are connected. And

  In a preferred aspect of the present invention, the yoke is formed by forging.

  In a preferred aspect of the present invention, the yoke is formed by cold working.

  In a preferred aspect of the present invention, the female serration is processed by a broach tool, and the blades of the broach tool are provided at uneven pitches in the circumferential direction.

  In addition, a steering device according to the present invention includes the universal joint described above.

  According to the present invention, it is possible to provide a universal joint excellent in durability performance and a steering device having the universal joint, in which the yoke has a sufficient shaft holding force, prevents abnormal wear and breakage of the teeth of the female serration. Can do.

FIG. 1 is a perspective view showing an overall configuration of a steering apparatus including a universal joint according to an embodiment. FIG. 2 is a side view of the upper side universal joint according to the embodiment. 3A shows a state in which the upper side yoke according to the embodiment is viewed from the upper side end surface, and FIG. 3B is a view taken along the line bb in FIG. 3A, and FIG. ) Is a cc arrow view of FIG. 3 (a), FIG. 3 (d) is a dd arrow view of FIG. 3 (a), and FIG. 3 (e) is a view of FIG. 3 (a). It is an ee arrow line view, FIG.3 (f) is an ff arrow line view of FIG.3 (c). 4 (a) and 4 (b) are enlarged cross-sectional views of the upper side yoke shown in FIG. 3 (c) with the output shaft inserted, and FIG. 4 (a) is a fastening view. The state before bolt fastening is shown, and FIG. 4 (b) shows the state after fastening bolt fastening. 5 (a) and 5 (b) are sectional views showing a coupling structure between a yoke and a shaft member in a conventional universal joint used in an electric power steering apparatus, and FIG. 5 (a) is a fastening bolt. The state before tightening is shown, and FIG. 5B shows the state after tightening the fastening bolt.

  Embodiments of the present invention will be described below with reference to the drawings. In the present specification, the directions related to the steering device and the universal joint are the same as the front-rear and left-right directions of the vehicle body when attached to the vehicle body unless otherwise specified. Further, the upper side and the rear side refer to the same direction, and the lower side and the front side refer to the same direction.

  FIG. 1 is a perspective view showing an overall configuration of a steering apparatus including an upper universal joint according to an embodiment of the present invention. The steering device according to the present embodiment is a rack and pinion type column assist type electric power steering device.

  As shown in FIG. 1, the steering device 100 includes a steering shaft 2 having a steering wheel 1 mounted on a rear end, a cylindrical steering column 3 in which the steering shaft 2 is rotatably supported on the inner diameter side, And a steering assist mechanism 4 connected to the front end portion of the steering shaft 2.

  The steering assist mechanism 4 includes a torque sensor (not shown), an electric motor 5 that generates an auxiliary steering torque according to the steering torque detected by the torque sensor, and a speed reduction mechanism 6 that is connected to the electric motor 5 and accommodated in a housing 6A. The auxiliary steering torque generated by the electric motor 5 is applied to the output shaft 7 of the steering auxiliary mechanism 4 via the speed reduction mechanism 6.

  The steering shaft 2 has an outer shaft 8 that is an upper shaft and an inner shaft 9 that is a lower shaft, and the outer shaft 8 and the inner shaft 9 have a structure that can reduce the overall length in the event of a collision. Further, the steering column 3 is formed by combining an outer column 10 as an upper column and an inner column 11 as a lower column in a telescope shape, and when an axial impact is applied, the steering column 3 absorbs impact energy and has a total length. It has a collapsible structure that shrinks.

  The outer column 10 of the steering column 3 is supported on the vehicle body side member 13 by the upper vehicle body side bracket 12U so that the tilt position and the telescopic position can be adjusted. The housing 6A of the speed reduction mechanism 6 is supported so as to be pivotable in the vertical direction about a pivot shaft 14p that is rotatably provided on a lower vehicle body side bracket 12L attached to the vehicle body side member 13.

  The rear end of the intermediate shaft 16 is connected to the output shaft 7 of the steering assist mechanism 4 via the upper side universal joint 15. A front end of the intermediate shaft 16 is connected to a pinion shaft 19 of a rack and pinion type steering gear mechanism 18 via a lower side universal joint 17. The upper side universal joint 15 includes an upper side yoke 20, a lower side yoke 22, and a cross shaft 24 that couples the pair of yokes 20, 22.

  The pinion shaft 19 is connected to the lower end yoke 26 of the lower universal joint 17 at the upper end. A rack shaft (not shown) is supported in the gear housing 18A so as to be movable in the vehicle width direction, and a pinion (not shown) of the pinion shaft 19 is engaged with rack teeth (not shown) of the rack shaft. Both ends of the rack shaft are connected to steered wheels (not shown) via tie rods 28 and 28, respectively.

  Since the steering device 100 has such a configuration, when a driver rotates the steering wheel 1, a torque sensor (not shown) detects a steering torque applied to the steering shaft 2, and is generated from the electric motor 5 in accordance with the detected steering torque. The auxiliary steering torque is transmitted to the output shaft 7 via the speed reduction mechanism 6 and further transmitted to the pinion shaft 19 via the intermediate shaft 16. When the pinion shaft 19 rotates, a rack shaft (not shown) engaged with the pinion shaft 19 is driven in the axial direction, that is, the vehicle width direction, and the left and right steered wheels connected to the tie rods 28 and 28 are steered.

FIG. 2 is a side view of the upper side universal joint 15 according to the embodiment of the present invention.
FIG. 3 is a six-side view of the upper side yoke 20 of the upper side universal joint 15, and FIG. 3A shows a state in which the upper side yoke 20 is viewed from the upper side end surface, that is, the end surface side of the steering shaft 2. 3 (b) is a view taken along the line bb in FIG. 3 (a), FIG. 3 (c) is a view taken along the line cc in FIG. 3 (a), and FIG. It is a dd arrow view of a), FIG.3 (e) is an ee arrow view of Fig.3 (a), FIG.3 (f) is ff arrow view of FIG.3 (c). FIG.
4 (a) and 4 (b) are enlarged cross-sectional views of the upper yoke 20 shown in FIG. 3 (c) in a state where the output shaft 7 is inserted. Shows the state before fastening bolt tightening, and FIG. 4B shows the state after fastening bolt tightening.

  As shown in FIG. 2, the upper side universal joint 15 according to this embodiment includes an upper side yoke 20, a lower side yoke 22, and a cross shaft 24 that couples the pair of yokes 20 and 22. . The output shaft 7 and the intermediate shaft 16 of the steering assist mechanism 4 are connected to the upper side yoke 20 and the lower side yoke 22, respectively (see FIG. 1).

  In the column assist type electric power steering apparatus, since the torque input to the universal joint 15 is large, the upper side yoke 20 of the universal joint 15 is not a press-molded product made of a plate material, but a cold forged product is used. ing. As a material for cold forging, carbon steel cast steel (SC material) or the like is used.

  As shown in each drawing of FIG. 3, the upper side yoke 20 (hereinafter also simply referred to as “yoke 20”) is a cylindrical connecting portion 30 into which the lower end of the output shaft 7 of the steering assist mechanism 4 is inserted and tightened. And a pair of arm portions 32, 32 that extend from the lower end of the connecting portion 30 in the axial direction of the connecting portion 30 and are connected to the lower yoke 22 through the cross shaft 24. The pair of arm portions 32 and 32 are a pair of plate-like members arranged to face each other, and each arm portion 32 is formed with a through hole 34 for supporting the cross shaft 24.

  The inner peripheral surface of the connecting portion 30 of the yoke 20 is formed in a cylindrical shape, and the inner diameter side thereof is a fitting hole 36 into which the lower end of the output shaft 7 is inserted and fitted. That is, the inner peripheral surface of the connecting portion 30 forms a fitting hole 36 as a peripheral wall of the fitting hole 36. The fitting hole 36 penetrates from the upper side end of the connecting portion 30 to the lower side end. The output shaft 7 is inserted into the fitting hole 36 from the upper side end of the connecting portion 30. A female serration 38 is provided on the inner peripheral surface of the connecting portion 30, that is, on the peripheral wall of the fitting hole 36. In the following description, with respect to the direction of the connecting portion 30 and the fitting hole 36, the upper side is referred to as the “shaft member insertion side” and the lower side is referred to as the “arm side”.

  A pair of thick portions 40, 40 having a thickness in the radial direction and extending in the axial direction and facing each other are provided on the outer peripheral portion of the connecting portion 30. The slit 42 formed between the thick portions 40, 40 penetrates in a radial direction from the outer peripheral surface of the connecting portion 30 to the fitting hole 36, and extends from the shaft member insertion side end of the connecting portion 30 to the vicinity of the arm side end. Extends in the direction.

  As shown in FIG. 3C, FIG. 3D, and FIG. 4A, in the vicinity of the shaft member insertion side end of the thick portions 40, 40, there is a direction across the slit 42, that is, the slit 42. Bolt insertion holes 44 are formed through the thick portions 40, 40 in a direction perpendicular to the radial direction penetrating the connecting portion 30 and perpendicular to the axial direction of the connecting portion 30. The bolt insertion hole 44 is formed to intersect the slit 42. A fastening bolt 45 for tightening (see FIG. 1) is inserted into the bolt insertion hole 44. The bolt insertion hole 44 is opened in a part of the fitting hole 36 on the slit 42 side. That is, the bolt insertion hole 44 and the fitting hole 36 partially intersect each other as shown in FIG. As shown in FIG. 3D, a counterbore 50 against which the head of the bolt 45 abuts is provided on the outer surface of one thick portion 40.

  As shown in FIG. 4A, a male serration 54 is formed on the outer peripheral surface of the output shaft 7. The plurality of teeth 55 of the male serration 54 are formed at an equal pitch in the circumferential direction. By tightening the fastening bolt 45 (see FIG. 1) inserted into the bolt insertion hole 44, the connecting portion 30 is tightened in the direction in which the pair of thick portions 40, 40 approach each other, and the output inserted into the fitting hole 36. The plurality of teeth 55 of the male serration 54 of the shaft 7 (see FIG. 1) and the plurality of teeth 39 of the female serration 38 of the fitting hole 36 mesh with each other, whereby the output shaft 7 and the connecting portion 30 are connected.

  In the present embodiment, as described above, the plurality of teeth 55 of the male serration 54 are formed at an equal pitch in the circumferential direction. On the other hand, the plurality of teeth 39 of the female serration 38 of the yoke 20 are formed unevenly in the circumferential direction. That is, the plurality of teeth 39 of the female serration 38 are not formed at an equal pitch over the entire circumference.

  When the connecting portion 30 is viewed from the axial direction, a straight line T that passes through the center axis C of the slit 42, that is, the center axis C of the fitting hole 36 and extends through the slit 42 in the radial direction is defined as a straight line T, and the fastening bolt insertion hole 44. The female serration 38 is indicated by an arrow F in FIG. 4 (a), where D is the central axis of the straight line and D is a straight line parallel to the central axis D and perpendicular to the central axis C and the straight line T of the fitting hole 36. The pitch of the teeth 39 in the circumferential range on the slit 42 side from the two intersections Q1, Q2 of the range, that is, the straight line E and the pitch circle of the female serration 38, is larger than the pitch of the teeth 39 in the remaining circumferential range. Has been. Specifically, the female serration 38 is formed such that the pitch of the teeth 39 gradually increases from the intersections Q1 and Q2 toward the slit 42. The teeth 39 are formed at equal pitches on the side of the female serration 38 on the side facing the slit 42 with respect to the center axis C from the intersections Q1 and Q2, that is, on the opposite side of the slit 42.

  Thus, the female serration 38 has a configuration in which the pitch of the teeth 39 in the half portion closer to the slit 42 than the central axis C in the circumferential range is larger than the pitch of the teeth 39 in the remaining circumferential range. In the state before the fastening bolt 45 is tightened, when the output shaft 7 and the yoke 20 are arranged concentrically, the gap between the male serration 54 and the female serration 38 is all the circumferential direction as shown in FIG. It is not constant over the entire circumference. Specifically, the gap between the male serration 54 and the female serration 38 gradually increases from the portion facing the slit 42 across the central axis C in any circumferential direction toward the slit 42. Yes.

  From this state, the bolt 45 is tightened, and the output shaft 7 and the connecting portion 30 are connected. As described in the background art section, the yoke 20 is less likely to be deformed than the central axis C of the female serration 38 (see the double arrow A in FIG. The portion on the opposite side to the slit 42 (see the double arrow B in FIG. 5B) has a structure that is easily deformed. Therefore, as the fastening bolt 45 is tightened, the yoke 20 deforms unevenly. In the present embodiment, since the gap between the male serration 54 and the female serration 38 becomes larger as it approaches the slit 42 in the state before the fastening bolt 45 is tightened, in the state where the tightening of the fastening bolt 45 is completed, FIG. 4 (b), the gap between the plurality of teeth 55 of the male serration 54 and the plurality of teeth 39 of the female serration 38 disappears over the entire circumference, and the teeth 55 and female of the male serration 54 extend over the entire circumference. The teeth 39 of the serration 38 are brought into close contact with each other.

  That is, in the present embodiment, the female serration 38 of the yoke 20 is formed in such a size that all the teeth 39 are in close contact with the teeth 55 of the male serration 54 of the output shaft 7 when the fastening bolt 45 is tightened. Has been.

  In addition, the female serration 38 provided with such a plurality of teeth 39 is processed by a broach tool (not shown). The blades of the broach tool are provided at uneven pitches in the circumferential direction corresponding to the pitch of the plurality of teeth 39 of the female serration 38.

  Thus, in the universal joint 15 according to the present embodiment, the state in which the teeth 55 of the male serration 54 and the teeth 39 of the female serration 38 are closely meshed with each other in the state where the tightening of the fastening bolt 45 is completed. Therefore, the surface pressure of the contact surface of the female serration 38 with the male serration 54 is evenly distributed over the entire circumference and becomes constant. That is, the female serration 38 does not generate high surface pressure locally on the contact surface with the male serration 54. Therefore, in the female serration 38, the average stress at the contact surface with the male serration 54 is reduced, and the teeth 39 of the female serration 38 can be prevented from being damaged due to repeated torque input, that is, the stress amplitude due to the subsequent steering operation. . In other words, by reducing the mean stress on the female serration 38, the fatigue limit until the female serration 38 is damaged due to repeated torque input by the steering operation, that is, the stress amplitude can be provided. As a result, the durability performance of the universal joint 15 can be improved.

  In addition, the universal joint 15 according to the present embodiment can be formed with high accuracy because the teeth 55 of the male serration 54 of the output shaft 7 are formed in a uniform shape in the axial direction, and the fastening bolt 45 can be tightened. In the completed state, since the teeth 55 of the male serration 54 and the teeth 39 of the female serration 38 are in close contact with each other over the entire circumference, the yoke 20 can have a sufficient shaft holding force.

  Thus, according to the present embodiment, the yoke has a sufficient shaft holding force, prevents abnormal wear and breakage of the female serration teeth, and is excellent in durability performance, and a steering apparatus having the universal joint Can be realized.

  In the above embodiment, the female serration 38 is formed so that the pitch of the teeth 39 gradually increases from the intersections Q1 and Q2 toward the slit 42, but the range on the slit 42 side from the intersections Q1 and Q2 The pitch of the teeth 39 may be equal. That is, the pitch of the teeth 39 in the range closer to the slit 42 than the intersections Q1 and Q2 may be formed at an equal pitch with a value larger than the pitch of the teeth 39 in the remaining range. Even with such a configuration, the same effects as those of the above-described embodiment can be exhibited.

  In the above embodiment, the female serration 38 has a configuration in which the pitch of the teeth 39 in the half range on the slit 42 side of the central axis C in the circumferential range is larger than the pitch of the teeth 39 in the remaining range. However, the range in which the pitch of the teeth 39 is formed to be large is at least the range of the above-described embodiment, that is, the half portion on the slit 42 side, and may be a range larger than this.

  In addition, the female serration 38 may be formed by forming the teeth 39 in the range of the slit 42 side from the intersections Q1 and Q2 with a module larger than the teeth 39 of other portions. That is, even if the size of the teeth 39 in the range on the slit 42 side from the intersections Q1 and Q2 is larger than the size of the teeth 39 in other portions, the same effect as in the above embodiment can be exhibited. .

  In the above embodiment, the present invention is applied to the upper side yoke 20 of the upper side universal joint 15 connected to the output shaft 7. However, the present invention is applied to the lower side yoke 20 of the upper side universal joint 15. It can also be applied to the lower universal joint 17.

DESCRIPTION OF SYMBOLS 1 Steering wheel 2 Steering shaft 3 Steering column 4 Steering assist mechanism 5 Electric motor 6 Deceleration mechanism 6A Housing 7 Output shaft 8 Outer shaft 9 Inner shaft 10 Outer column 11 Inner column 12U Upper bracket 12L Lower bracket 13 Car body side member 14P Pivot shaft 15 Upper side universal joint 16 Intermediate shaft 17 Lower side universal joint 18 Steering gear mechanism 18A Gear housing 19 Pinion shaft 20 Upper side yoke 22 Lower side yoke 24 Cross shaft 28 Tie rod 30 Connecting portion 32 Arm portion 34 Through hole 36 Fitting hole 38 Female Serration 39 Female serration teeth 40 Thick part 42 Slit 44 Bolt insertion hole 45 Fastening bolt 50 Counterbore 54 Male serration 55 Male serration tooth 100 Stearin Equipment

Claims (10)

The crosshair,
A pair of yokes connected via the cross shaft,
The pair of yokes are provided with female serrations meshing with male serrations formed on the outer peripheral surface of the shaft member on the inner peripheral surface, each having a cylindrical connecting portion into which the shaft member is inserted,
At least one of the connecting portions of the pair of yokes has a pair of opposing portions that form slits that extend in the radial direction from the outer peripheral surface to the inner peripheral surface and extend in the axial direction. In the universal joint connected to the shaft member by deforming the facing parts in a direction approaching each other,
The female serration has a first circumferential range in which a plurality of teeth are formed at an equal pitch on the side opposite to the slit with respect to the central axis of the connecting portion, and the slit side of the first circumferential range. And a second circumferential range in which a plurality of teeth are formed at a pitch larger than the pitch of the plurality of teeth in the first circumferential range.   2. The universal joint according to claim 1, wherein the plurality of teeth in the second circumferential range are formed such that a pitch gradually increases as the distance to the slit approaches. 3.   The universal joint according to claim 1, wherein the plurality of teeth in the second circumferential range are formed at an equal pitch.   4. The method according to claim 1, wherein the second circumferential range is at least a half of the circumferential range of the female serration on the slit side with respect to the central axis of the connecting portion. The universal joint according to item.   When the shaft member and the connecting portion are arranged concentrically in a state before the pair of opposing portions are deformed in a direction approaching each other by the screw member, the gap between the male serration and the female serration is the connecting portion. 5. The universal joint according to claim 1, wherein the universal joint gradually increases from a portion on the side opposite to the slit with respect to the central axis of the center axis toward the slit. 6.   Any one of 1 to 5, wherein the plurality of teeth of the female serration are meshed with the plurality of teeth of the male serration in a state where the coupling portion and the shaft member are coupled. Universal joints as described in   The universal joint according to any one of claims 1 to 6, wherein the yoke is formed by forging.   The universal joint according to any one of claims 1 to 7, wherein the yoke is formed by cold working.   9. The female serration is processed by a broach tool, and the blades of the broach tool are provided at uneven pitches in the circumferential direction. Universal joint.   A steering apparatus comprising the universal joint according to claim 1.

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