JP2012180909A - Structure for connecting universal joint york and shaft - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure for connecting a universal joint york and a shaft, which prevents incomplete serration fitting between the universal joint york and the shaft from being fastened and fixed, and facilitates serration fitting.SOLUTION: The structure for connecting a universal joint york and a shaft includes: the universal joint york which has female serration formed on the inner peripheral surface and expands and contracts the female serration inner diameter by forming a slit over the female serration from the outer circumferential surface; and the shaft in which the male serration fitted to the female serration is formed on one side end part. One side of a valley-plugged part or a missing tooth part is formed on the outer circumferential surface of the male serration, and the other side of the valley-plugged part or the missing tooth part is formed on the inner peripheral surface of the female serration. A small-diameter cylindrical part is formed on the shaft end side from the male serration part formed on the end part of the shaft.

Description

  The present invention relates to a connection structure between a universal joint yoke and a shaft of a steering device.

  Conventionally, when the serration fitting between the steering device shaft and the universal joint yoke has to be carried out at a specific relative phase in the rotational direction, there has been a problem that assembling work is troublesome.

  As a prior art for improving this portion, there is Japanese Utility Model Publication No. 62-25540, which is provided by providing a raised portion on a part of the serration tooth of the pinion shaft and a missing tooth portion on the female serration portion of the yoke. The pinion shaft can be inserted only at a specific rotational direction phase.

Japanese Utility Model Publication No. 62-25540

  However, this prior art requires phase alignment in the rotational direction while aligning the serration axis during serration fitting, making assembly work difficult, and further, serrations are formed up to the pinion shaft end. As a result, the bolts are tightened while the serration of the pinion shaft is only fitted to the yoke, and there is a risk of assembly without securing the serration fitting length as designed. There was a problem.

In order to solve the above problems, the present invention provides a universal joint yoke in which a female serration is formed on the inner peripheral surface and the inner diameter of the female serration can be increased or decreased by forming a slit through the female serration from the outer peripheral surface. When,
In the joint structure of the universal joint yoke and the shaft, the male serration that fits into the female serration is composed of a shaft formed at one end,
While forming one of the valley filling portion or the missing tooth portion on the outer peripheral surface of the male serration, forming the other of the valley filling portion or the missing tooth portion on the inner peripheral surface of the female serration,
A cylindrical portion having a diameter smaller than the outer diameter of the male serration portion is formed on the shaft end side of the male serration portion formed at the end portion of the shaft.

According to the present invention, when the serration is fitted, the small-diameter cylindrical portion serves as an axis alignment guide, so that the phase alignment of the serration can be easily performed, and the assembly work is facilitated.
Even if the bolt is tightened when the shaft is fitted to the universal joint yoke only a short length, the shaft ends are small in diameter and cannot be tightened to each other, so that incorrect assembly can be prevented. There is.

It is a figure which shows the schematic of the steering device for motor vehicles. A side view of the pinion shaft 1 is shown. The BB arrow line view of FIG. 2 is shown. The yoke 2 which is a component of the universal joint 51 is shown. 4B shows a side view of the yoke 2, and FIG. 4A shows a cross-sectional view taken along the line C-C in FIG. 4B.

Hereinafter, an embodiment of the present invention will be described. FIG. 1 shows a schematic view of a steering apparatus for an automobile according to the present technology.
As shown in FIG. 1, the steering device for an automobile transmits the rotation of a steering wheel (not shown) attached to the end of the steering shaft 7 to the pinion shaft 1 of the steering gear unit. The pair of left and right tie rods 31, 31 is pushed and pulled to give a steering angle to the front wheels (steering wheels; not shown). The steering wheel is supported and fixed to the rear end portion of the steering shaft 7, and the steering shaft 7 is rotatably supported in a state where the electric power steering device 61 is inserted. Further, the front end portion of the steering shaft 7 is connected to the rear end portion of the intermediate shaft 5 via a universal joint 52, and the front end portion of the intermediate shaft 5 is connected to the pinion shaft 1 via another universal joint 51. is doing. The yoke 2 that is a component of the universal joint 51 and the pinion shaft are coupled by serration fitting. The illustrated example incorporates an electric power steering device 61 that uses the electric motor 62 as an auxiliary power source to reduce the force required for the driver to operate the steering wheel.

  A steering device equipped with a rack and pinion type steering gear unit as a mechanism for converting the rotational motion input from the steering wheel into a linear motion for giving a steering angle can be configured to be small and light, and has rigidity. Widely used because it provides a high and good steering feeling. This steering gear unit is formed by meshing pinion teeth 11 (FIG. 2) provided on a part of the pinion shaft 1 with rack teeth provided on a rack 3 built in the gear housing 4. When the pinion shaft 1 is rotated by the operation of the steering wheel, the rack 3 is displaced in the axial direction within the rack housing portion of the gear housing 4 based on the meshing of the pinion teeth 11 and the rack teeth, and 1 connected to both ends thereof The pair of tie rods 31, 31 are pushed and pulled to give a desired steering angle to the steered wheels.

FIG. 2 shows the pinion shaft 1, FIG. 3 shows a BB arrow view of FIG. 2, and FIG. 4 shows a sectional view and a side view of the yoke 2 that is a component of the universal joint 51.
As shown in the AA sectional view of FIG. 2, pinion teeth 11 are formed at one end of the pinion shaft 1 and mesh with the rack teeth of the rack 3. A cylindrical body 12 is formed at a substantially central portion of the pinion shaft 1. As shown in FIG. 3, a male serration (or spline) 14 is formed on the outer periphery of the other end of the pinion shaft 1.

  4B shows a side view of the yoke 2, and FIG. 4A shows a cross-sectional view taken along the line C-C in FIG. 4B. A female serration (or spline) 22 is formed on the inner peripheral surface of the yoke 2 shown in FIG. 4A and is fitted to the serration 14 of the pinion shaft 1. A through hole 23 and a female screw are formed in the yoke 2 in a direction perpendicular to the axial direction of the serration, and a slit 24 is formed so as to penetrate from the outer peripheral surface of the yoke toward the serration 22. After the serration fitting between the yoke 2 and the pinion shaft 1, the width of the slit 24 is narrowed by screwing and tightening a bolt (not shown) to the through hole 23 and the female screw, and the inner diameter of the serration 22 is reduced accordingly. As a result, the yoke 2 and the pinion shaft 1 can be fixed so as not to be relatively movable.

  As shown in FIG. 2, an R-shaped groove 15 is formed on a part of the outer peripheral surface of the serration 14 of the pinion shaft 1. The pinion shaft 1 and the yoke 2 are serrated and fitted, and a groove 15 is formed as a relief groove so that the bolt can be inserted when the bolt is inserted into the through hole 23. Accordingly, since the bolt can be inserted only when the serration 14 is inserted into the serration 22 by a predetermined length, the assembly work of the relative positioning in the axial direction between the pinion shaft 1 and the yoke 2 is facilitated. Further, the outer diameter of the body 12 of the pinion shaft 1 may be larger than the inner diameter of the serration 22 of the yoke 2. By doing so, when the serration 14 of the pinion shaft 1 is inserted too much into the serration 22 of the yoke 2, the end of the body 12 and the end of the yoke 2 come into contact with each other, and no further insertion is possible. Work becomes easier.

  As shown in FIG. 3, the serration 14 of the pinion shaft 1 is provided with valley filling portions 16 at three locations in the circumferential direction. The serration 14 has a plurality of male serration teeth in the circumferential direction and extends in the axial direction, but does not form a groove in the valley between some of the adjacent serration teeth, and the serration has a large diameter. The valley filling portion 16 is formed as it is. Although the example which has arrange | positioned the valley filling part 16 at three places in the circumferential direction is shown in FIG. 3, what is necessary is just to form one or more places.

  The serrations 22 of the yoke 2 are also formed with three toothless portions 21 in the circumferential direction in the same phase as the valley filling portion 16 so that the valley filling portion 16 of the pinion shaft 1 can be inserted. The serration 22 is formed with a plurality of female serration teeth in the circumferential direction and extending in the axial direction. ing. Although FIG. 4A shows an example in which the missing tooth portions 21 are arranged at three locations in the circumferential direction, one or more locations may be formed so as to correspond to the valley filling portions 16 of the pinion shaft 1. In this embodiment, the valley filling portion 16 is formed on the pinion shaft side and the tooth missing portion 21 is formed on the yoke side. Conversely, the tooth missing portion is formed on the pinion shaft side and the yoke side is formed. A valley filling portion may be formed.

  By forming the valley filling portion 16 in the pinion shaft 1 and the missing tooth portion 21 in the yoke 2 in this way, the serrations 14 and 22 of the pinion shaft 1 and the yoke 2 can be inserted only at specific relative rotational positions. The phase alignment work between the serrations becomes unnecessary, and the assembly work becomes easy.

  Further, as shown in FIG. 2, a cylindrical small diameter portion 13 is formed at the other end portion of the pinion shaft and at the shaft end portion than the serration 14. The outer diameter of the small diameter portion 13 is preferably smaller than the outer diameter of the serration 14. The outer diameter of the small diameter portion 13 is more preferably smaller than the small serration diameter of the serration 22 when the yoke 2 is screwed and tightened with a bolt in a state where the serration 14 and the serration 22 are not fitted. Further, the outer diameter of the small-diameter portion 13 may be made as large as possible within the preferred range so that the bolt does not pass through the through-hole 23 in a state where the pinion shaft serration 14 and the yoke serration 22 are slightly fitted. Further, the cross-sectional shape of the small diameter portion is not limited to a circle, and may be any cross-sectional shape such as a polygon or an ellipse. Further, in this embodiment, the serration 14 is formed at the other end portion of the pinion shaft 1 and the pinion teeth 11 are formed at one end portion. However, the pinion teeth are not essential requirements, and the end portion is not required. Any shaft shape may be used as long as the shaft is formed with serrations.

  As described above, conventionally, when the yoke 2 and the pinion shaft 1 are serrated and fitted, the rotational direction phase is determined and the axes are aligned so that the valley filling portion 16 and the toothless portion 21 are aligned. I had to insert it and it was difficult to do it. However, by forming the small-diameter portion 13 as in the present embodiment, the phase adjustment operation in the rotational direction can be performed with the small-diameter portion 13 inserted into the serration portion of the yoke 2, so that the assembling operation becomes easier.

  It can be used as a steering device.

1 Pinion shaft (shaft)
2 York
13 Small diameter part
14 Serration
16 Valley filling
21 missing teeth
22 Serration
51 universal joint

Claims (2)

A universal joint yoke that has a female serration formed on the inner peripheral surface and that extends through the slit from the outer peripheral surface to the female serration, and can expand and contract the female serrated inner diameter,
In the joint structure of the universal joint yoke and the shaft, the male serration that fits into the female serration is composed of a shaft formed at one end,
While forming one of the valley filling portion or the missing tooth portion on the outer peripheral surface of the male serration, forming the other of the valley filling portion or the missing tooth portion on the inner peripheral surface of the female serration,
A coupling structure of a universal joint yoke and a shaft, wherein a cylindrical portion having a smaller diameter is formed on the shaft end side of the male serration portion formed at the end portion of the shaft. In the connection structure of the universal joint yoke and the shaft according to claim 1,
A pinion tooth is formed at the other end of the shaft, and the universal joint yoke and shaft connection structure.

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