JP7119284B2 - UNIVERSAL JOINT AND STEERING DEVICE WITH THE UNIVERSAL JOINT - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a universal joint used in a steering system or the like, and a steering system having the universal joint.

Conventionally, in a universal joint in which a fitting portion with a shaft member such as a steering shaft is serrated and fastened with the shaft member by a tightening force of a bolt, female serrations are formed on the inner peripheral surface of the shaft member fitting hole of the yoke. and a female serration non-formed region, that is, a toothless portion.

For example, in Patent Document 1, a central angle θ centered on the central axis of the shaft member fitting hole of the yoke and corresponding to the female serration non-formed region is set to a predetermined value within the range of 100° to 140°. A universal joint is described.
Further, Patent Document 2 describes a universal joint in which toothless portions are formed in serrations formed on the inner peripheral surface of a shaft member fitting hole that face each other in a diametrical direction perpendicular to the slit direction. there is
Further, Patent Document 3 discloses a universal joint in which a toothless portion in which no female serration is formed is provided on the inner peripheral surface of a shaft member fitting hole, and the toothless portion is used as a space for accommodating burrs generated when a slit is formed. York is mentioned.

Japanese Patent Application Laid-Open No. 2012-193798 Japanese Utility Model Laid-Open No. 52-169641 Japanese Patent Application Laid-Open No. 2003-200238

In an electric power steering system, when a steering shaft is rotated leftward or rightward by steering, a torque sensor detects steering torque applied to the steering shaft, and assist steering torque is generated from an electric motor in accordance with the detected steering torque. is transmitted to the output shaft of the steering assist mechanism through the speed reduction mechanism. When the steering wheel is turned back or cut out, excessive torque is applied to the steering shaft, and this excessive torque is repeatedly applied to the shaft member fitting portion of the universal joint, that is, the serration teeth, via the output shaft of the steering assist mechanism. is entered. In particular, in a column-assist type electric power steering apparatus, a large amount of torque is input to the universal joint. Therefore, the yoke of the universal joint is required to have a high holding force with respect to the fitted shaft member.

FIG. 6 shows an example of a yoke of a conventional universal joint used in a column-assist type electric power steering device, and is a cross-sectional view of the yoke as seen from the axial direction. A yoke 320 shown in FIG. 6 is the yoke on the side to which the output shaft of the steering assist mechanism is fitted, of the pair of yokes forming the universal joint. As shown in FIG. 6, the inner peripheral surface of the shaft member fitting hole 336 is provided with a female serration 338 and a toothless portion 354 where the female serration 338 is not formed. When viewed from the axial direction of the shaft member fitting hole 336, the toothless portion 354 is formed in a range of the root circle of the female serration 338 centered on the slit 342 in which the bolt insertion hole 344 of the tightening bolt crosses the root circle. It is provided on the inner peripheral surface corresponding to the arc.

In the column-assist type electric power steering device, as described above, the torque input to the universal joint is large, so the yoke of the universal joint is not press-formed from a plate but is formed by cold forging. . Carbon steel cast steel (SC material) or the like is used as a material for cold forging. Carbon steel cast steel has a lower elongation than cold-rolled steel sheets (SPCC, SPHC) and the like used for press-formed plate materials. In the tightened state, the teeth of the entire female serration of the press-formed one come into contact with the male serration of the output shaft, but the cold-forged one has little elongation. The stress concentrates on the serration teeth of , and meshing tends to become stronger in this range. As a result, fretting wear occurs on the serration teeth of that portion.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and provides a universal joint that has a high holding force for a shaft member to be fitted and can prevent fretting wear of serration teeth due to stress concentration. An object of the present invention is to provide a steering device with a joint.

In order to solve the above problems, a universal joint according to the present invention comprises a cross shaft and a pair of yokes connected via the cross shaft, and at least one of the pair of yokes has an inner peripheral surface as a shaft. A pair of cylindrical connecting portions forming a fitting hole to be fitted with the member is provided, and the connecting portion forms a slit extending in the axial direction and penetrating from the outer peripheral surface to the inner peripheral surface in the radial direction. It has a thick portion, and is connected to the shaft member by tightening the pair of thick portions by a screw member in a direction approaching, and is fitted with the shaft member in a partial range of the inner peripheral surface in the circumferential direction. In a universal joint provided with female serrations and provided with a toothless region in which the female serrations are not formed in the remaining range in the circumferential direction, the pair of thick portions includes a first thick portion and a first thick portion. It is characterized by comprising a second thick portion that is thicker than the first thick portion.

A preferred aspect of the present invention is characterized in that the virtual plane passing through the center of the slit is provided parallel to the axial direction of the connecting portion and away from the center line of the fitting hole.

Further, in a preferred aspect of the present invention, the connecting portion has a screw insertion hole through which the screw member is inserted, the screw insertion hole is composed of a through hole portion and a female screw portion, and the through hole portion comprises: It is characterized by being provided in the first thick portion.

A preferred aspect of the present invention is characterized in that the screw insertion hole is orthogonal to the radial direction of the fitting hole and orthogonal to the axial direction of the fitting hole.

Further, in a preferred aspect of the present invention, the toothless region includes a first toothless portion provided on the side of the first thick portion in the circumferential direction across the slit and the second thick portion in the circumferential direction. and a second toothless portion provided on the side of the screw, wherein the second toothless portion is provided in a circumferential range including the shortest portions of the screw insertion hole and the fitting hole. .

Moreover, a steering device according to the present invention is characterized by including the universal joint described above.

According to the present invention, there is provided a universal joint which has a high holding force with respect to a fitted shaft member and which can prevent fretting wear of the serration teeth due to stress concentration, and a steering device provided with the universal joint. can be done.

1 is a perspective view showing the overall configuration of a steering device provided with a universal joint according to a first embodiment; FIG. 1 is a side view of a universal joint according to a first embodiment; FIG. It is an enlarged perspective view of an upper side yoke, and (a), (b), and (c) show states viewed from different angles. 6A and 6B are six views of the upper yoke. FIG. FIG. 4(d) is an enlarged cross-sectional view taken along the line AA. FIG. 4 is an enlarged cross-sectional view of a yoke of a conventional universal joint;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. In this specification, the directions of the steering device and the universal joint are the same as the longitudinal and lateral 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.

(First embodiment)
FIG. 1 is a perspective view showing the overall configuration of a steering device provided with an upper universal joint according to a first embodiment of the invention. The steering device according to the present embodiment is a rack-and-pinion 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 attached to its rear end, a cylindrical steering column 3 in which the steering shaft 2 is rotatably supported on the inner diameter side, A steering assist mechanism 4 connected to the front end of the steering shaft 2 is provided.

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

The steering shaft 2 has an outer shaft 8, which is an upper shaft, and an inner shaft 9, which is a lower shaft. The steering column 3 is formed by combining an outer column 10, which is an upper column, and an inner column 11, which is a lower column, in a telescopic manner. It has a collapsible structure that shrinks.

An outer column 10 of the steering column 3 is supported by an upper vehicle body side bracket 12U on a vehicle body side member 13 so as to be able to adjust its tilt position and telescopic position. The housing 6A of the speed reduction mechanism 6 is rotatably supported in the vertical direction around a pivot shaft 14p rotatably provided on a lower vehicle body side bracket 12L attached to the vehicle body side member 13. As shown in FIG.

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

A lower-side yoke 26 of the lower-side universal joint 17 is connected to the upper end of the pinion shaft 19 . A rack shaft (not shown) is movably supported in the vehicle width direction in the gear housing 18A, and a pinion (not shown) of the pinion shaft 19 meshes with rack teeth (not shown) of the rack shaft. Both ends of the rack shaft are connected to steerable wheels (not shown) via tie rods 28, 28, respectively.

Since the steering apparatus 100 is configured as described above, when the driver turns the steering wheel 1, a torque sensor (not shown) detects the steering torque applied to the steering shaft 2, and the electric motor 5 generates torque according to the detected steering torque. The assisted 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, the rack shaft (not shown) meshing with the pinion shaft 19 is driven in the axial direction, that is, in the vehicle width direction, and the left and right steerable wheels connected to the tie rods 28, 28 are steered.

FIG. 2 is a side view of the upper universal joint 15 according to the first embodiment of the invention.
FIG. 3 is an enlarged perspective view of the upper yoke 20 of the upper universal joint 15, with (a), (b), and (c) showing states viewed from different angles.
4A and 4B are six views of the upper yoke 20. FIG. In FIG. 4, (a) shows the state of the upper yoke 20 viewed from the upper end surface, that is, the end surface on the side of the steering shaft 2, (b) is a bb arrow view of (a), and (c) ) is a cc arrow view of (a), (d) is a dd arrow view of (a), (e) is an ee arrow view of (a), ( f) is a view taken along line ff of (d).

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

As shown in FIGS. 3 and 4, the upper yoke 20 (hereinafter simply referred to as "yoke 20") has a tubular shape to which the lower end of the output shaft 7 of the steering assist mechanism 4 is fitted and tightened. and a pair of arm portions 32, 32 extending axially outward of the connecting portion 30 from the lower end of the connecting portion 30 and connected to the lower yoke 22 via the cross shaft 24. I have. The pair of arm portions 32 , 32 are a pair of plate-like members arranged facing each other, and each arm portion 32 is formed with a through hole 34 in which the cross shaft 24 is supported.

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 serves as 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 the fitting hole 36 as a peripheral wall of the fitting hole 36 . A female serration 38 is provided on the inner peripheral surface of the connecting portion 30 , that is, the peripheral wall of the fitting hole 36 . A male serration (not shown) that meshes with the female serration 38 is formed on the outer peripheral surface of the output shaft 7 .

A first thick portion 40 and a second thick portion 41 having a thickness in the radial direction and extending in the axial direction are provided on the outer peripheral side of the connecting portion 30 . A slit 42 formed between the first thick portion 40 and the second thick portion 41 radially penetrates from the outer peripheral surface of the connecting portion 30 to the fitting hole 36 and extends from the upper end portion of the connecting portion 30 . It extends in the axial direction to the vicinity of the lower end.

FIG. 5 is an enlarged sectional view taken along line AA in FIG. 4(d).
As shown in FIGS. 4(c), 4(d), and 5, near the upper end portions of the first thick portion 40 and the second thick portion 41, there are formed fitting holes in the direction across the slit 42, that is, fitting holes. The first thick portion 40 and the second thick portion 41 are penetrated in a direction perpendicular to the radial direction of the fitting hole 36 and perpendicular to the axial direction of the fitting hole 36 , and the bolt insertion hole 44 intersects the slit 42 . formed. A tightening bolt (not shown) is inserted through the bolt insertion hole 44 . The bolt insertion hole 44 is open 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. Specifically, as shown in FIG. 5, when viewed from the axial direction of the connecting portion 30, the bolt insertion hole 44 has a generatrix on the side of the center axis C of the fitting hole 36 of the generatrix of the bolt insertion hole 44. It intersects and traverses the inner peripheral surface of the connecting portion 30 .

As shown in FIG. 5, the bolt insertion hole 44 includes a female threaded portion 46 (on the left side as viewed from the paper surface) formed on the inner peripheral surface of the second thick portion 41 and a first thick portion 46 with the slit 42 interposed therebetween. A through-hole portion 48 (on the right side as viewed in the drawing) that forms the cylindrical inner peripheral surface of the thick portion 40 . A tightening bolt is inserted into the bolt insertion hole 44 from the through hole portion 48 side. A side surface of the first thick portion 40 and the connecting portion 30 is provided with a counterbore 50 with which the head of the bolt abuts. By tightening the bolt inserted into the bolt insertion hole 44 , the connecting portion 30 is tightened in a direction in which the first thick portion 40 and the second thick portion 41 approach each other, and the output shaft 7 inserted into the fitting hole 36 is tightened. The male serrations (see FIG. 1) and the female serrations 38 of the fitting hole 36 are engaged with each other, whereby the output shaft 7 and the connecting portion 30 are connected.

As shown in FIG. 5, the inner peripheral surface of the connecting portion 30, i.e., the female serration 38 of the fitting hole 36, has a substantially triangular cross-sectional shape and is composed of a large number of ridges extending in the axial direction continuously in the circumferential direction. It is These ridges constitute a large number of female serration teeth 52 . In this embodiment, the female serrations 38 are not provided along the entire circumference of the inner peripheral surface of the connecting portion 30 . As shown in FIG. 5, the vicinity of the slit 42 of the inner peripheral surface of the connecting portion 30 is a toothless portion 54 where the female serration 38 is not formed. The toothless portion 54 is on the cylindrical inner peripheral surface having a curvature that matches the root circle of the female serration 38 .

The toothless portion 54 on the inner peripheral surface of the connecting portion 30 is provided in a predetermined range in the circumferential direction across the slit 42 when the connecting portion 30 is viewed from the axial direction. That is, the toothless portion 54 is formed from an intersection point P on the slit side of intersection points between a virtual plane T passing through the center of the slit 42 and the root circle of the female serration 38 when the connecting portion 30 is viewed from the axial direction. They are provided on the inner peripheral surface corresponding to a predetermined range of circular arcs on both sides in the peripheral direction of the bottom circle. That is, the toothless portion 54 is provided in a predetermined range on the first thick portion 40 side and on the through hole portion 48 side of the bolt insertion hole 44 on the inner peripheral surface of the connecting portion 30 with the slit 42 therebetween. 1 toothless portion 56 and a second toothless portion 58 provided in a predetermined range on the female screw portion 46 side of the bolt insertion hole 44 and on the second thick portion 41 side.

The specific range of the through-hole portion 48 side of the bolt insertion hole 44 in which the first toothless portion 56 is provided is as follows. First, it is assumed that the female serrations 38 are formed along the entire circumference of the inner peripheral surface of the connecting portion 30 . In this case, among the numerous female serration teeth 52 formed on the portion of the inner peripheral surface corresponding to the slit 42 side of the central axis C of the fitting hole 36 and the through hole portion 48 side of the imaginary plane T, When viewed from the axial direction of the connecting portion 30, one of the tooth flanks is perpendicular to the central axis D of the bolt insertion hole 44, i. A female serration tooth 52a having a serration is contemplated.

In this embodiment, in the root circle of the female serration 38, the range of the inner peripheral surface corresponding to the arc from the intersection point P to the portion including the female serration tooth 52a is defined as the first toothless portion 56. As shown in FIG. In other words, the portion from the portion of the female serration 38 corresponding to the slit 42 to the female serration tooth 52 a is the first toothless portion 56 . Note that the axial force of the bolt acts in a direction perpendicular to the axial direction of the connecting portion 30 .

On the other hand, the predetermined range on the female thread 46 side of the bolt insertion hole 44 in which the second toothless portion 58 is provided is as follows in detail. First, it is assumed that the female serrations 38 are formed along the entire circumference of the inner peripheral surface of the connecting portion 30 as in the case of the first toothless portion 56 . In this case, among the many female serration teeth 52 formed in the portion of the inner peripheral surface corresponding to the slit 42 side of the central axis C of the fitting hole 36 and the female screw portion 46 side of the imaginary plane T, A female serration tooth 52b located at the terminal end on the central axis C side of the range where the bolt insertion hole 44 intersects the fitting hole 36 when viewed from the axial direction of the portion 30 is conceivable.

In this embodiment, when the connecting portion 30 is viewed from the axial direction, and a straight line E that passes through the center axis C of the fitting hole 36 and is parallel to the imaginary plane T, the root circle of the female serration 38 is: The range of the inner peripheral surface corresponding to the arc from the intersection point P to the portion including the female serration tooth 52b passing through the point Q where the straight line E and the root circle of the female serration 38 intersect is the second toothless portion. 58. In other words, the portion from the portion of the female serration 38 corresponding to the slit 42 to the female serration tooth 52b, that is, the area where the bolt insertion hole 44 intersects the fitting hole 36, to the central axis C side end is the second is a toothless portion 58 of .

As described above, the yoke 20 of the upper universal joint 15 according to the present embodiment has two toothless portions 56 and 58 with different circumferential ranges formed on the inner peripheral surface of the yoke 20 with the slit 42 interposed therebetween. In other words, on the inner peripheral surface of the yoke 20, toothless portions 56 and 58 are formed over the circumferential region on both sides of the slit 42 as the center.

In this embodiment, the imaginary plane T passing through the center of the slit 42 is offset from the central axis line C of the fitting hole 36, and more specifically, passes through the first thick portion 40 side. Moreover, the slit 42 is provided on the side of the first thick portion 40 with respect to the straight line E. As shown in FIG.

Next, a method of connecting the yoke 20 of the upper universal joint 15 and the output shaft 7 (see FIG. 1) according to this embodiment will be described.
First, the output shaft 7 is inserted into the fitting hole 36 of the yoke 20 . At this time, the female serration 38 of the yoke 20 and the male serration (not shown) of the output shaft 7 are loosely fitted. Next, a tightening bolt (not shown) is inserted into the bolt insertion hole 44 from the through hole portion 48 side, and the bolt is tightened.

As the bolt is tightened, the connecting portion 30 is tightened in a direction in which the first thick portion 40 and the second thick portion 41 approach each other. Here, since the first thick portion 40 is thinner than the second thick portion 41, the connecting portion 30 on the side of the first thick portion 40 bends more than the connecting portion 30 on the side of the second thick portion 41. . Since the first toothless portion 56 is provided on the inner peripheral surface of the connecting portion 30 on the side of the first thick portion 40 , the male serration and the female serration do not engage with each other near the slit 42 and bend. Thus, the male serrations of the output shaft 7 mesh with the female serrations 38 of the connecting portion 30 over a wide range in the circumferential direction of the connecting portion 30 . As a result, the holding range for holding the output shaft 7 of the connecting portion 30, that is, the range of meshing contact with the output shaft 7 is increased, and the holding force is increased.

In this embodiment, the second toothless portion 58 is provided in a circumferential range including the point Q which is the shortest portion between the bolt insertion hole 44 and the fitting hole 36 . Therefore, by tightening the bolt, the output shaft 7 is tightened to the connecting portion 30 while being shifted to the shortest side of the bolt insertion hole 44 having the second toothless portion 58 and the fitting hole 36, ie, the bolt side. At this time, since the male serration and the female serration do not mesh in the second toothless portion 58, the male serration of the output shaft 7 meshes with the female serration 38 of the connecting portion 30 over a wide range in the circumferential direction of the connecting portion 30. becomes. As a result, the holding range for holding the output shaft 7 of the connecting portion 30, that is, the range of meshing contact with the output shaft 7 is increased, and the holding force is increased.

As described above, according to the present embodiment, by providing the first thick portion 40 and the second thick portion 41 having different thicknesses in the connecting portion 30, the output shaft 7 can be moved around the wide circumference of the female serration 38 on the other side. Engagement is possible over a range of orientations. As a result, even in the yoke formed by cold forging, the shaft holding force of the connecting portion 30 can be increased.

Further, by providing the first toothless portion 56, fretting wear of the serration teeth in the vicinity of the slit 42 where stress concentrates can be prevented.

Further, by providing the second toothless portion 58, the step of removing burrs generated when forming the slits 42 in a blank (not shown) for forming the yoke 20 can be omitted.
A blank integrally comprising a tubular portion and a yoke portion for forming the yoke 20, wherein the tubular portion is formed with a female serration 38 and first and second toothless portions 56, 58. In order to form the slits 42 in the tubular portion, the tubular portion is cut from the outer peripheral side to the inner peripheral side. When such cutting is performed, burrs are generated when the cutting tool protrudes toward the inner peripheral side of the cylindrical portion, that is, toward the female serration 38 side.

The burrs produced in this manner interfere with fitting the male serrations of the output shaft 7 to the yoke 20 or the female serrations 38 of the blank. In this embodiment, by providing the second toothless portion 58 connected to the slit 42 , burrs generated by cutting work are prevented from coming into contact with the fitting portion between the male serration and the female serration 38 . That is, the second toothless portion 58 serves as a space for accommodating such burrs. As a result, when fitting the output shaft 7 to the female serration 38, the step of removing burrs can be omitted. As a result, manufacturing costs can be reduced. It should be noted that the connection portion of the first toothless portion 56 with the slit 42 also has the same effect.

In the above embodiment, the imaginary plane T passing through the center of the slit passes through the through-hole side, but it can also pass through the female thread side. At this time, the thick portion on the female thread side becomes thinner than that on the through hole side, and the bending of the connecting portion on the female thread side increases, so that the male serration and the female serration 38 engage over a wide circumferential range. be able to. Moreover, in the above embodiment, the present invention is applied to the upper universal joint of the steering device 100, but the present invention can also be applied to the lower universal joint. Also, in each of the above embodiments, the present invention is applied to the upper yoke, but may be applied to both the upper yoke and the lower yoke.

1 steering wheel 2 steering shaft 3 steering column 4 steering assist mechanism 5 electric motor 6 reduction 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 vehicle 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 40 First thick portion 41 Second thick portion 42 Slit 44 Bolt insertion hole 46 Female screw portion 48 Through hole portion 50 Counterbore 52 Female serration tooth 54 Toothless portion 56 First toothless portion 58 Second toothless portion Part 100 steering device

Claims (5)

a cross and
and a pair of yokes connected via the cross shaft,
At least one of the pair of yokes has a cylindrical connecting portion having an inner peripheral surface forming a fitting hole for fitting with the shaft member,
The connecting portion is formed with a slit extending in the axial direction and penetrating from the outer peripheral surface to the inner peripheral surface in the radial direction,
The connecting portion has a pair of thick portions spaced apart in the width direction of the slit, and the connecting portion and the shaft member are connected by tightening the pair of thick portions in a direction approaching each other with a screw member. a female serration that engages with the shaft member is provided in a partial range in the circumferential direction of the inner peripheral surface, and a toothless region in which the female serration is not formed is provided in the remaining range in the circumferential direction;
The missing tooth region is an arc extending along the root circle of the female serration,
The pair of thick portions are
a first thick portion;
a second thick portion that is thicker in the width direction than the first thick portion and is made of a single member ;
The connecting portion has a screw insertion hole through which the screw member is inserted. The screw insertion hole is composed of a through hole portion and a female screw portion. A portion is provided, and the internal thread portion is provided on the inner circumference of the second thick portion,
When viewed from the centerline direction of the fitting hole of the connecting part, the center of the slit in the width direction is located closer to the first thick part than the centerline of the fitting hole. universal joint. 2. The universal joint according to claim 1, wherein a virtual plane passing through the center of the slit in the width direction is provided parallel to the axial direction of the connecting portion and away from the center line of the fitting hole. 2. The universal joint according to claim 1, wherein the screw insertion hole is orthogonal to the radial direction of the fitting hole and orthogonal to the axial direction of the fitting hole. The toothless region includes a first toothless portion provided on the first thick portion side in the circumferential direction across the slit and a second toothless portion provided on the second thick portion side in the circumferential direction. 4. The universal joint according to claim 3, wherein the second toothless portion is provided in a circumferential range including the shortest portions of the screw insertion hole and the fitting hole. A steering device comprising the universal joint according to any one of claims 1 to 4.

Images