JP2005083531A - Spline shaft - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an excellent durability and a low cost by realizing a sure removal of a looseness in a spline shaft using a rolling element. <P>SOLUTION: An orbital way 18 is partitioned between orbital grooves 16 and 17 extended in a longitudinal direction of an outer shaft 13 and an inner shaft 14. Balls 15 form one row along each orbital way 18. A holder 19 extended along each orbital way 18 holds each ball 15 formed in a row at each orbital way 18. Annular elastic members 22, such as a ring spring, etc., are alternately disposed along outer surfaces 19a and inner surface 19b of the adjacent holders 19. The balls 15 are alternately energized radially inward Y and radially outward Z in the inner shaft 14 in corresponding each row via each holder 19. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a spline shaft in which an inner shaft and an outer shaft are connected via a rolling element so as to be relatively movable in the axial direction and capable of transmitting torque.

In an automobile steering apparatus, the intermediate shaft is provided between the steering shaft and the steering gear, and transmits a rotational operation force applied to the steering wheel to the steering gear side.
In general, as the intermediate shaft, a ball spline structure is employed in which a plurality of balls forming a row aligned in the axial direction of the intermediate shaft are interposed between corresponding track grooves formed on the inner shaft and the outer shaft.

Usually, in order to smoothly move the inner shaft and the outer shaft relative to each other in the axial direction, a predetermined gap is required between the inner surface of the raceway groove and the ball. The backlash in the rotational direction during the period increases.
Therefore, in order to adjust the above gap with high accuracy, it is necessary to polish the track. In addition, so-called matching assembly is used in which the inner shaft and the outer shaft are sorted into a plurality of groups according to the dimensional accuracy of the raceway grooves, and the inner shaft and outer shaft groups are used in combination to achieve the predetermined clearance accuracy. We are carrying out. However, in these cases, the manufacturing cost becomes high.

Thus, for example, it has been proposed that the raceway groove of the inner shaft is constituted by a thin plate or other elastic member, and this elastic member urges the rolling element to the raceway groove of the outer shaft (for example, Patent Documents 1, 2, and 3). .
International Publication WO03 / 031250A1 JP 2001-50293 A German patent DE 3730393C2

However, the bias is applied only to one side of the inner shaft or the outer shaft, and the backlash removal may be uncertain. Further, it is very difficult to manage the accuracy of the elastic member for constituting the track, and the manufacturing cost increases if the accuracy control is strictly performed.
The present invention has been made in view of the above problems, and an object of the present invention is to provide a spline shaft that can reliably remove backlash, has excellent durability, and is inexpensive.

To solve the above problem,
The present invention includes an outer shaft and an inner shaft fitted together, a track groove extending in the longitudinal direction of the outer shaft and the inner shaft, facing each other, a track formed between the track grooves facing each other, and each track In a spline shaft comprising rolling elements that form a row along each track, a cage that extends along each track path and holds the rolling elements that form a row in each track path, and a corresponding row via each cage It further comprises biasing means for biasing the rolling elements alternately inward and radially outward of the inner shaft.

  In this case, the urging means urges the rolling elements alternately through the cages radially inward and radially outward of the inner shaft, thereby ensuring that the radial play between the outer shaft and the inner shaft is prevented. It can be removed and durability can be improved. Further, the track only needs to be provided on the inner shaft and the outer shaft itself, and compared with the case where the track is provided on an elastic member such as a thin plate, accuracy management is easy, and the manufacturing cost can be reduced.

It is preferable that the biasing means includes an annular elastic member, and the annular elastic member is alternately along the outer surface and the inner surface of the adjacent cages. In this case, the radial play between the outer shaft and the inner shaft can be removed by urging the rolling element via the cage with a simple structure.
The present invention also includes an outer shaft and an inner shaft that are fitted to each other, track grooves that extend in the longitudinal direction of the outer shaft and the inner shaft and that face each other, a track path that is formed between the track grooves that face each other, and each track. A spline shaft comprising rolling elements each in a row along a path, further comprising a cage extending along each track path and holding the rolling elements in a row in each track path, each cage corresponding It has a function of alternately energizing rolling elements that form a row on the track path to one and the other in the rotation direction of the inner shaft. In this case, the play in the circumferential direction of the outer shaft and the inner shaft can be removed.

In the present invention, each cage may include a corrugated member extending so as to sew in a zigzag manner between the rolling elements forming a row on the corresponding track. In this case, the play in the circumferential direction of the outer shaft and the inner shaft can be removed with a simple structure using corrugated members.
Further, in the present invention, each retainer includes a plate having a plurality of retaining holes that respectively retain the rolling elements arranged in a row on the corresponding track, and the retaining hole of each plate includes one of the rotation directions of the inner shaft and On the other hand, they may be arranged in a zigzag shape with their positions alternately shifted. In this case, the play in the circumferential direction of the outer shaft and the inner shaft can be removed with a simple structure having only the layout of the positions of the holding holes of the plate constituting the cage.

Preferred embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a schematic view of a steering device in which a spline shaft according to an embodiment of the present invention is applied to an intermediate shaft, and FIG. 2 is a cross-sectional view of a main part of the spline shaft.
Referring to FIG. 1, a steering device 1 includes a steering shaft 3 having a steering member 2 such as a steering wheel (not shown) fixed at one end, and a spline connected to the steering shaft 3 via a universal joint 4 so as to be integrally rotatable. A vehicle having an intermediate shaft 5 as a shaft, a pinion shaft 7 connected to the intermediate shaft 5 via a universal joint 6 so as to be integrally rotatable, and a rack 8a meshing with a pinion 7a provided on the pinion shaft 7. And a rack shaft 8 extending in the left-right direction.

Tie rods 9 are coupled to both ends of the rack shaft 8, and each tie rod 9 is connected to a corresponding steering wheel 11 via a corresponding knuckle arm 10.
The rack shaft 8 is supported by a housing 12 via an unillustrated bearing so as to be movable in the axial direction. A steering mechanism A is configured including the pinion shaft 7, the rack shaft 8, the tie rod 9, the knuckle arm 10, and the steered wheel 11.

When the steering member 2 is operated and the steering shaft 3 is rotated, this rotation is converted into a linear motion of the rack shaft 8 along the left-right direction of the vehicle by the pinion 7a and the rack 8a. Thereby, steering of the steered wheel 11 is achieved.
The intermediate shaft 5 includes a cylindrical outer shaft 13 and an inner shaft 14 fitted with the outer shaft 13 with play. The outer shaft 13 and the inner shaft 14 are connected so as to be capable of relative movement in the axial direction X and to transmit torque via balls 15 as a plurality of rows of rolling elements.

  2, track grooves 16 and 17 extending in the axial direction are formed on the inner periphery of the outer shaft 13 and the outer periphery of the inner shaft 14, respectively. Although not shown, the raceway grooves 16 of the outer shaft 13 and the raceway grooves 17 of the inner shaft 14 are arranged at equal intervals in the circumferential direction and face each other. A track path 18 is defined between the track grooves 16 and 17 of the outer shaft 13 and the inner shaft 14 facing each other. In each track 18, the balls 15 described above are interposed in one row arranged in the axial direction. Referring to FIG. 5, the cross section of each raceway groove 16, 17 forms an arc having a radius slightly larger than the radius of ball 15.

  Referring again to FIG. 2, the balls 15 in each row are collectively held in the corresponding track 18 by a common holder 19. As shown in FIG. 3 and FIG. 4, the retainer 19 is made of, for example, a synthetic resin, and is made of a long plate member that extends along the axial direction X with an arc cross section. As shown in FIG. 3, the retainer 19 forms a retaining hole 20 for the ball 15 that is arranged at predetermined intervals along the longitudinal direction.

Moreover, the intermediate part of the longitudinal direction of the adjacent holder | retainer 19 is connected via the connection part 21 which can be elastically deformed, and, thereby, the cyclic | annular unit U is formed by the some holder 19 and the some connection part 21. Yes. The cage 19 and the connecting portion 21 are preferably molded from an integral synthetic resin.
As shown in FIG. 4, this embodiment is characterized by an urging means for alternately urging adjacent cages 19 radially inward Y and radially outward Z of the inner shaft. The annular elastic member 22 is provided. Specifically, the annular elastic member 22 is made of a metal ring spring (snap ring) having a C shape and has open ends 22a and 22b. The annular elastic members 22 are alternately along the outer surface 19a and the inner surface 19b of the cage 19 adjacent to each other.

According to the present embodiment, as shown in FIG. 5, the ball 15 is moved through the cages 19 by the annular elastic member 22 in the radially inward direction Y (that is, the raceway groove 17 side) of the inner shaft 14 and radially outward. By alternately energizing in the direction Z (that is, on the raceway groove 16 side), the radial play of the outer shaft 13 and the inner shaft 14 can be reliably removed, and durability can be improved.
Further, it is not necessary to finish the raceway grooves 16 and 17 and the manufacturing cost can be reduced. Furthermore, the track only needs to be directly provided on the outer shaft 13 and the inner shaft 14, and the accuracy control is easier than in the case where the track is provided on an elastic member such as a thin plate, and also in this respect, the manufacturing cost is reduced. Can do.

Further, the balls 15 can be alternately urged in both directions in the radial direction via the cage 19 by a simple structure in which the annular elastic members 22 are alternately arranged along the outer surface 19a and the inner surface 19b of the adjacent cage 19. It is preferable.
An O-ring may be used as the annular elastic member 22. Moreover, as shown in FIG. 6, it is preferable to provide the outer surface 19a and the inner surface 19b of the retainer 19 with a groove 23 into which the annular elastic member 22 can be fitted.

In the present embodiment, the retainer 19 is made of synthetic resin and the annular elastic member 22 made of a metal ring spring is used. However, when the retainer 19 is made of metal, a connecting portion connected to the retainer 19 is used. 21 may function as a leaf spring, and an urging force may be obtained by bending elasticity of the connecting portion 21. In this case, the annular elastic member can be eliminated.
FIG. 7 shows another embodiment of the present invention. Referring to FIG. 7, a feature of the present embodiment is that balls 15 forming a row on each track 24 corresponding to each cage 24 are alternately arranged in one direction R <b> 1 and the other direction R <b> 2 in the rotation direction of the inner shaft 14. It has the function of energizing.

  Specifically, each retainer 24 is formed of a corrugated member extending so as to sew between the balls 15 forming a row in the corresponding track 18 so as to sew in a zigzag manner. In other words, the cage 24 forms holding portions 25 (corresponding to so-called pockets) for the balls 15 in opposite directions with respect to the rotation direction. In the present embodiment, the play in the rotational direction of the outer shaft 13 and the inner shaft 14 can be reliably removed with a simple structure using the cage 24 made of a corrugated member. Further, the track only needs to be provided directly on the outer shaft 13 and the inner shaft 14, and the polishing finish of the track grooves 16, 17 can be eliminated, so that the manufacturing cost can be reduced.

Note that the end of the corrugated member constituting the cage 24 has a narrow corrugated pitch, and serves as a buffer portion 26 for reducing the impact when the cage 24 collides with the end surface of the track 18.
Next, FIG. 8 shows still another embodiment of the present invention. In the present embodiment, each retainer 27 is made of a plate having a plurality of retaining holes 28 for retaining the balls 15 that are lined up in the corresponding track 18. The holding hole 28 of the retainer 27 made of a plate is arranged in a zigzag shape in which the position is alternately shifted to one of the rotation directions R1 and R2 of the inner shaft 14, and the corresponding ball 15 is placed in one of the rotation directions of the inner shaft 14. The R1 and the other R2 are alternately energized.

According to the present embodiment, the play in the rotational direction of the outer shaft 13 and the inner shaft 14 can be removed with a simple structure having only the layout of the positions of the holding holes 28 of the plate constituting the cage 27. Further, the track only needs to be directly provided on the outer shaft 13 and the inner shaft 14, and the polishing finish of the track grooves 16 and 17 can be eliminated, so that the manufacturing cost can be reduced.
In addition, this invention is not limited to said each embodiment, A various change can be given in the claim of this invention.

1 is a schematic view of a steering device in which a spline shaft according to an embodiment of the present invention is applied to an intermediate shaft. It is sectional drawing of the intermediate shaft as a spline shaft. It is a schematic perspective view of the unit containing a holder | retainer. It is a schematic side view which shows the state which hold | maintained the ball | bowl by the unit containing a holder | retainer. It is sectional drawing of the principal part of an intermediate shaft. It is sectional drawing of the example of a change of a holder | retainer. It is a disassembled perspective view of the holder of a spline shaft of another embodiment of the present invention, and an inner axis. It is a disassembled perspective view of the holder of a spline shaft of another embodiment of the present invention, and an inner axis.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Steering device 2 Steering member 3 Steering shaft 5 Intermediate shaft (spline shaft)
7 Pinion shaft 8 Rack shaft 13 Outer shaft 14 Inner shaft 15 Ball (rolling element)
16, 17 raceway groove 18 raceway 19 cage 19a outer surface 19b inner surface 20 retaining hole 21 connecting portion 22 annular elastic member (biasing means)
23 Groove 24 Cage 25 Holding part 26 Buffering part 27 Cage 28 Holding hole X Axial direction Y Radial inward Z Radial outward R1 One of the rotational directions R2 The other of the rotational directions

Claims (5)

The outer shaft and the inner shaft fitted together, the track grooves extending in the longitudinal direction of the outer shaft and the inner shaft, facing each other, the track formed between the track grooves facing each other, and a row along each track In a spline shaft comprising rolling elements forming
A cage that extends along each track and holds rolling elements in a row in each track,
A spline shaft, further comprising: an urging unit that alternately urges the rolling elements radially inward and radially outward of the inner shaft for each corresponding row via each cage.   2. The spline shaft according to claim 1, wherein the biasing means includes an annular elastic member, and the annular elastic member alternately follows the outer surface and the inner surface of the cage adjacent to each other. The outer shaft and the inner shaft fitted together, the track grooves extending in the longitudinal direction of the outer shaft and the inner shaft, facing each other, the track formed between the track grooves facing each other, and a row along each track In a spline shaft comprising rolling elements forming
A cage that holds the rolling elements that extend along each track and that forms a row in each track;
A spline shaft, wherein each cage has a function of alternately energizing rolling elements arranged in a row on a corresponding track path in one and the other in the rotation direction of the inner shaft.   4. The spline shaft according to claim 3, wherein each cage includes a corrugated member extending so as to sew in a zigzag manner between the rolling elements arranged in a row on a corresponding track path.   4. The retainer according to claim 3, wherein each retainer includes a plate having a plurality of retaining holes respectively retaining the rolling elements arranged in a row on the corresponding track path, and the retaining holes of the respective plates are one and the other in the rotation direction of the inner shaft. The spline shaft is characterized by being arranged in a zigzag shape alternately shifted in position.

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