JP5370201B2 - Universal joint yoke - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To support a large load applied on a universal joint by increasing the rigidity of an arm part around a bearing hole for pivotally supporting a joint cross. <P>SOLUTION: Faces 55, 55 on the outer side in the radial direction of a pair of arm parts are pressed inwardly in the radial direction (the direction of a white arrow 56 in Fig.2(b)) by a face-pressing punch of a cylindrical shape, and circumferential edges of bearing holes 521, 521 are work-hardened. Thus, the rigidity of the circumferential edges of the bearing holes 521, 521 of the pair of arm parts is increased, and a large load applied to a universal joint can be supported. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a universal joint yoke, and more particularly to a universal joint yoke that connects shafts that transmit rotation of a steering shaft of a steering device.

  In a steering device that steers the front wheels of a vehicle, the movement of a steering shaft that is rotated by the operation of a steering wheel is transmitted to an input shaft of a steering gear through a universal joint.

  The movement of the steering wheel is transmitted to the steering gear via a steering shaft and an intermediate shaft that are rotatably provided in the steering column, and the direction of the wheel is steered by the steering gear. Usually, the steering shaft and the input shaft of the steering gear cannot be provided on the same straight line.

  For this reason, conventionally, an intermediate shaft is provided between the steering shaft and the input shaft to the steering gear, the end of the intermediate shaft and the steering shaft, and the end of the intermediate shaft and the end of the input shaft of the steering gear. Are coupled via a universal joint so that power can be transmitted between the steering shaft and the input shaft that do not exist on the same straight line.

  In recent years, there has been an increasing number of column assist type electric power steering devices in which an assist device for applying a steering assist force to a steering shaft is provided between an intermediate shaft and a steering wheel.

  In such column assist type electric power steering, since the rotational torque applied to the intermediate shaft is increased, the rigidity of the universal joint, particularly the rigidity of the arm portion around the bearing hole for supporting the cross shaft is improved. It needs to be bigger.

  The universal joint shown in Patent Document 1 is formed by projecting a cylindrical build-up on the radially outer side of the arm portion around the bearing hole to project a cylindrical build-up, and the area of the bearing hole that supports the bearing. And the rigidity of the arm portion around the bearing hole for supporting the cross shaft is increased.

  However, since the universal joint shown in Patent Document 1 has a thin cylindrical build-up, when the load applied to the universal joint increases, the cylindrical build-up plastically deforms, and the arm portion around the bearing hole is deformed. Rigidity may be reduced.

JP 10-148217 A

  It is an object of the present invention to provide a universal joint yoke capable of supporting a large load applied to the universal joint by increasing the rigidity of the arm portion around the bearing hole for supporting the cross shaft. And

The above problem is solved by the following means. That is, the first invention is a pair of coupling cylinders for coupling the shafts so that rotational torque can be transmitted, and a pair of bearing holes provided integrally with the coupling cylinders for supporting the cross shafts. and an arm portion, the universal joint of Yo molded by plastic working the plate material - in click, the pair of arm portions, press the peripheral surface of the radially outer side of the bearing hole of the arm portion surface punch by, by pushing plane radially inwardly, the arm portions having an increased rigidity by work hardening the periphery of the bearing hole while the cylindrical surface low of swing circle without padding projecting radially outward characterized by the, as well as to be able to support a large load applied to the universal joint, that has a small installation space of the universal joint to reduce the swing circle Universal joint to Yo - a click.

  A second aspect of the invention is a universal joint yoke characterized in that in the universal joint yoke of the first aspect, the inner peripheral surface of the bearing hole is burnished and work hardened.

  In the universal joint yoke of the present invention, the radially outer surfaces of the pair of arm portions are pressed inward in the radial direction, and the periphery of the bearing hole is work-hardened. Therefore, since the rigidity of the periphery of the bearing hole of a pair of arm part becomes large, the big load added to a universal joint can be supported. Moreover, since the cylindrical build-up protruding outward in the radial direction is not required, the diameter (swing circle) of the space around which the universal joint swings can be reduced, and the installation space for the universal joint can be reduced.

  In the universal joint yoke of the present invention, the inner peripheral surface of the bearing hole is burnished and work hardened. Therefore, since the roundness and surface roughness of the inner peripheral surface of the bearing hole are improved, the durability and accuracy of the universal joint are further improved.

It is the whole steering device provided with the universal joint of the example of the present invention. The yoke of the universal joint of the Example of this invention is shown, (a) is a front view, (b) is a right view of (a).

  FIG. 1 is an overall side view of a steering apparatus including a universal joint according to an embodiment of the present invention. As shown in FIG. 1, a steering apparatus having a universal joint according to an embodiment of the present invention has a steering shaft 12 on which a steering wheel 11 can be mounted on the rear side of the vehicle body (right side in FIG. 1), and the steering shaft 12 is inserted. The steering column 13, an assist device (steering assisting portion) 20 for applying an assist torque to the steering shaft 12, and a rack / pinion mechanism (not shown) on the front side of the vehicle body (left side in FIG. 1) of the steering shaft 12 And a steering gear 30 connected to each other.

  The steering shaft 12 is spline-fitted between a female steering shaft 12A and a male steering shaft 12B so as to be able to transmit rotational torque and to be relatively movable in the axial direction. Therefore, when the female steering shaft 12A and the male steering shaft 12B collide, the spline fitting portion moves relative to each other so that the total length can be shortened.

  The cylindrical steering column 13 inserted through the steering shaft 12 combines an outer column 13A and an inner column 13B so as to be telescopically movable. Therefore, the steering column 13 has a so-called collapsible structure in which, when an impact in the axial direction is applied during a collision, the entire length is reduced while absorbing energy due to the impact.

  The vehicle body front side end portion of the inner column 13B is press-fitted and fixed to the vehicle body rear side end portion of the gear housing 21. Further, the front end portion of the male steering shaft 12B on the vehicle body is passed through the inside of the gear housing 21 and connected to the rear end portion of the assist device 20 on the rear side of the input shaft (not shown).

  The steering column 13 is supported by a support bracket 14 at a middle portion thereof on a part of the vehicle body 18 such as a lower surface of the dashboard. Further, a locking portion (not shown) is provided between the support bracket 14 and the vehicle body 18, and when an impact in a direction toward the front side of the vehicle body is applied to the support bracket 14, the support bracket 14 is locked to the locking bracket 14. It moves away from the vehicle and moves to the front side of the vehicle.

  The upper end portion of the gear housing 21 is also supported on a part of the vehicle body 18. In the case of this embodiment, by providing a tilt mechanism and a telescopic mechanism, the position of the steering wheel 11 in the longitudinal direction of the vehicle body and the height position can be freely adjusted. Such a tilt mechanism and a telescopic mechanism are well known in the art and are not characteristic features of the present invention, and thus detailed description thereof is omitted.

  The output shaft 23 protruding from the front end face of the gear housing 21 on the vehicle body is connected to the rear end portion of the intermediate shaft 15 via a universal joint (upper universal joint) 4. Further, a pinion shaft (hereinafter referred to as a shaft) 6 of the steering gear 30 is connected to the front end portion of the intermediate shaft 15 via another universal joint (lower universal joint) 5. The intermediate shaft 15 is fitted on the vehicle body front side of the male intermediate shaft (male shaft) 15A on the vehicle body rear side of the female intermediate shaft (female shaft) 15B so as to be able to transmit rotational torque and relatively move in the axial direction. Is fitted.

  A pinion (not shown) is formed at the lower end (front end of the vehicle body) of the shaft 6. A rack (not shown) meshes with the pinion, and rotation of the steering wheel 11 moves the tie rod 31 to steer a wheel (not shown).

  A case 261 of an electric motor 26 is fixed to the gear housing 21 of the assist device 20, and a worm is coupled to a rotating shaft (not shown) of the electric motor 26. A worm wheel (not shown) is attached to the output shaft 23, and the worm of the rotating shaft of the electric motor 26 is engaged with the worm wheel.

  A torque sensor (not shown) is provided around the intermediate portion of the output shaft 23. The direction and magnitude of the torque applied from the steering wheel 11 to the steering shaft 12 is detected by a torque sensor, and the electric motor 26 is driven in accordance with the detected value via a reduction mechanism comprising a worm and a worm wheel. Then, the output shaft 23 is caused to generate auxiliary torque with a predetermined magnitude in a predetermined direction. The assist device that generates the auxiliary torque is not limited to an electric type, and may be a hydraulic assist device.

  FIG. 2 shows a coupling portion between one of the pair of yokes 51, 51 constituting the universal joint 5 of the embodiment of the present invention and the shaft 6. That is, FIG. 2 shows the yoke of the universal joint of the embodiment of the present invention, (a) is a front view, and (b) is a right side view of (a).

  As shown in FIG. 2, bifurcated arm portions 52, 52 are formed on the upper side of the universal joint yoke 51 (upper side in FIG. 2), and the arm portions 52, 52 have circular bearing holes. 521 and 521 are formed. A cross shaft is inserted into the bearing holes 521 and 521 via a bearing (not shown), and is coupled to the other yoke 51 (not shown) via the cross shaft. The yoke 51 is preferably manufactured by press-molding a thick plate material having a wall thickness of about 8 mm, and the length of the bearing holes 521 and 521 is ensured to be large so that the area of the bearing holes 521 and 521 is increased.

  A substantially cylindrical coupling cylinder portion 53 is formed on the lower side of the yoke 51 (lower side in FIG. 2). The coupling cylinder portion 53 is connected to the inner peripheral surface 531 of the coupling cylinder portion 53 from the lower side in FIG. The shaft 6 is inserted parallel to the axial direction.

  A pair of left and right flange portions 54, 54 extending in the tangential direction from the coupling cylinder portion 53 are formed in the coupling cylinder portion 53 of the yoke 51. A slit (cut) 56 communicating with the inner peripheral surface 531 is formed between the flange portions 54, 54. The slit 56 is formed over the entire length of the coupling cylinder portion 53 in the axial direction.

  Bolt holes 541 and 541 for inserting bolts (not shown) are concentrically formed in the flange portions 54 and 54. In addition, seat surfaces 542 and 542 are formed on the flange portions 54 and 54. 2 is in contact with the lower surface of the bolt head of the bolt. The right seat surface 542 in FIG. 2 is in contact with the lower surface of a nut (not shown) screwed into the bolt shaft portion of the bolt.

  The shaft 6 is inserted into the inner peripheral surface 531 of the coupling cylinder portion 53, and bolts are inserted into the bolt holes 541 and 541 from the left side of FIG. When the nut is screwed into the bolt shaft portion of the bolt, the flange portions 54 and 54 are elastically deformed and the groove width of the slit 56 is narrowed, and the outer peripheral surface of the shaft 6 is firmly tightened and fixed by the inner peripheral surface 531 of the coupling tube portion 53. be able to.

  The surfaces 55 and 55 on the radially outer side of the pair of arm portions 52 and 52 are pressed (pressed) radially inward (in the direction of the white arrow 57 in FIG. 2B) by a cylindrical surface pressing punch (not shown). Then, the peripheral edges of the bearing holes 521 and 521 are work-hardened. By doing so, the rigidity of the peripheral edges of the bearing holes 521 and 521 of the pair of arm portions 52 and 52 is increased, so that a large load applied to the yoke 51 of the universal joint 5 can be supported.

  In addition, since the rigidity of the arm portions 52 and 52 can be increased by surface pressing using a press, the number of machining steps can be reduced. Furthermore, since the cylindrical build-up protruding outward in the radial direction as in the prior art is not required, the diameter (swing circle) of the space around which the universal joint swings can be reduced, and the installation space for the universal joint can be reduced. .

  In addition, after roughing the bearing holes 521 and 521 by turning or the like, the inner peripheral surfaces of the bearing holes 521 and 521 are preferably finished by roller burnishing. In this way, the inner peripheral surfaces of the bearing holes 521 and 521 are work-hardened, and the roundness and surface roughness of the inner peripheral surfaces of the bearing holes 521 and 521 are improved. Further improve.

  In the above-described embodiment, an example in which the bolt is tightened and applied to a pinch bolt type universal joint that couples the shaft to the coupling cylinder portion has been described. However, the universal coupling of the type that couples the shaft to the coupling cylinder portion by welding or caulking is described. You may apply.

DESCRIPTION OF SYMBOLS 11 Steering wheel 12 Steering shaft 12A Female steering shaft 12B Male steering shaft 13 Steering column 13A Outer column 13B Inner column 14 Support bracket 15 Intermediate shaft 15A Male intermediate shaft 15B Female intermediate shaft 18 Car body 20 Assist device 21 Gear housing 23 Output shaft 26 Electric Motor 261 Case 30 Steering gear 31 Tie rod 4 Universal joint (upper universal joint)
5 Universal joint (lower universal joint)
51 Yoke 52 Arm part 521 Bearing hole 53 Coupling cylinder part 531 Inner peripheral surface 54 Flange part 541 Bolt hole 542 Seat surface 55 Radial outer surface of the arm part 56 Slit (cut)
57 White arrow 6 axis (pinion axis)

Claims (2)

A coupling cylinder for coupling the shafts so as to be able to transmit rotational torque;
A pair of arm portions provided integrally with the coupling cylinder portion and having bearing holes for supporting the cross shaft;
In a universal joint yoke formed by plastic processing of a plate material ,
The pair of arms are
This arm portion radially outward of the bearing hole peripheral surface of the pressing surface punch of, by pushing plane radially inwardly, the cylindrical surface low of swing circle without padding projecting radially outward In addition, by making the arm portion work hardening the periphery of the bearing hole to increase the rigidity,
A universal joint yoke characterized in that a large load applied to the universal joint can be supported and the swing circle is reduced to reduce the installation space for the universal joint. The universal joint yoke according to claim 1,
A universal joint yoke characterized in that the inner peripheral surface of the bearing hole is burnished and work hardened.

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