JP2004360730A - Extendible shaft - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily manufacture an extendible shaft having a pair of spline coupled axles at a low cost. <P>SOLUTION: The extendible shaft includes a looseness preventive member 9 made of an elastic material and mounted at the diameter reduction section 8 of a male spline 5. The looseness preventive member 9 has a pair of legs 10, 11 extends and curves in a circumferential direction of the diameter reduction section 8, a coupling part 12 for coupling between opposed one ends 10a, 11a of the legs 10, 11, and an elastic pressing piece part 13 extending and curving in substantially the same direction as the legs 10, 11 from the coupling part 12 for elastically pressing the female spline 3 of an outer axle 1 at the outside of the curve from the legs 10, 11. The legs 10, 11 and the elastic pressing piece 13 can be bent and formed in the same direction. A manufacturing step can be simplified. A pressing load can be easily regulated by regulating the curvature, etc. of the elastic pressing piece 13. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a telescopic shaft, and more particularly to an improvement in a structure for preventing generation of vibration due to a play in fitting between a pair of shaft portions included in the telescopic shaft.
[0002]
[Prior art]
The telescopic shaft is used, for example, as a steering shaft of an automobile.
The telescopic shaft is used as an intermediate shaft that connects a steering shaft of an automobile and a steering mechanism such as a rack and pinion mechanism, for example. In this case, the expansion and contraction function is used for adjusting the length of the intermediate shaft for absorbing the relative displacement between the steering gear and the column when the vehicle is running, or for adjusting the length of the intermediate shaft during assembly.
[0003]
Generally, a spline or serration is employed as a structure for fitting a pair of shaft portions included in the telescopic shaft.
For example, an end of an inner shaft having a male spline (external spline) engaging with the female spline is inserted into a fitting hole having a female spline (internal spline) formed at an end of the outer shaft. And the two shafts are integrally rotatably connected.
[0004]
In this case, if there is no clearance between the male spline and the female spline, the inner shaft cannot be inserted into the fitting hole. However, the clearance is disturbed, and the two shaft portions are relatively displaced in the radial direction and the circumferential direction, causing an uncomfortable rattle to the driver.
Therefore, conventionally, a telescopic shaft using a play preventing member as shown in FIG. 7 has been provided (Patent Document 1).
[0005]
In the telescopic shaft 51 of Patent Literature 1, a male spline 53 is formed on the inner shaft portion 52, and a female spline 54 that fits into the male spline 53 is formed on the inner peripheral surface of a fitting hole 56 of the outer shaft portion 55. ing. The male spline 53 is bisected in the axial direction as a first portion 53a and a second portion 53b, and a reduced diameter portion 57 is formed between the two portions 53a, 53b. It is adapted to be fitted.
[0006]
Referring to FIGS. 7 and 8, rattling preventing member 58 is curved in the same direction as leg portion 59 and a pair of curved leg portions 59 extending in the circumferential direction of reduced diameter portion 57, and is curved in direction M1. It is made of an elastic body having a leg portion 59 and a body portion 60 formed by bending in a direction M2 perpendicular to the direction M2. The body portion 60 is elastically contacted with the female spline 54 of the outer shaft portion 53.
[0007]
[Patent Document 1]
Utility Model Registration No. 2593916 [0008]
[Problems to be solved by the invention]
However, in the above-described play prevention member 58, since the bending directions M1 and M2 of the pair of leg portions 59 and the body portion 60 are different from each other, the work of changing the setup of the press forming apparatus and the like increase, and the manufacturing process becomes complicated. Therefore, there is a problem that the manufacturing cost increases.
Further, since there are two directions M1 and M2 of the bending, it is difficult to set the pressing load.
[0009]
The present invention has been made in view of the above problems, and an object of the present invention is to provide a telescopic shaft that is easy to manufacture, inexpensive, and easy to set a load.
[0010]
Means for Solving the Problems and Effects of the Invention
In order to achieve the above object, a first aspect of the present invention is to insert an inner shaft portion having an axially formed male spline engaging with the female spline into a fitting hole of an outer shaft portion having a female spline formed axially. In a telescopic shaft in which a male spline is divided in the axial direction by providing a reduced diameter portion in a part of the inner shaft portion, a play preventing member made of an elastic body is disposed at the reduced diameter portion, The prevention member has a pair of legs that extend and bend in the circumferential direction of the reduced diameter portion, a connecting portion that connects between opposing ends of the pair of legs, and a connecting portion that is substantially in the same direction as the legs. And a resilient pressing piece that elastically presses the female spline of the outer shaft portion outside the curve from the leg portion by extending and bending.
[0011]
In the present invention, since the predetermined portion of the inner shaft portion is pressed against the corresponding portion of the outer shaft portion by the pressing reaction force of the elastic pressing piece portion, the backlash in the radial direction of both shaft portions is killed, and the abnormal noise accompanying the backlash is reduced. Can be suppressed. In addition, the leg portion for holding the reduced diameter portion of the inner shaft portion and the elastic pressing piece portion for elastically pressing the female spline of the outer shaft portion extend and curve in substantially the same direction, so that the leg portion and the elastic pressing portion are bent. The one part can be bent in the same direction. As a result, the manufacturing process is simplified, and the manufacturing cost can be reduced. Further, the elastic pressing force can be easily adjusted by adjusting the degree of curvature of the elastic pressing piece.
[0012]
According to a second aspect of the present invention, in the first aspect, the engaging portion provided on at least one of the distal end portion of the leg portion or the edge portion of the connecting portion on the opposite side is provided on the reduced diameter portion of the inner shaft portion. It is characterized in that it engages with the mating groove and that the tip of the elastic pressing piece engages with the valley of the female spline of the outer shaft. According to the present invention, the relative rotation of the two shaft portions can be restricted, the play in the rotation direction can be suppressed, and the generation of the unusual noise accompanying this can be suppressed.
[0013]
A third invention is characterized in that, in the first or second invention, the pair of legs and the connecting portion are formed to have the same curvature and bend in the same direction. According to the present invention, the pair of leg portions and the connecting portion can be formed collectively by bending, so that the manufacturing cost can be further reduced.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Preferred embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is an exploded perspective view of a telescopic shaft according to an embodiment of the present invention, and FIG. 2 is a side view of a play preventing member mounted on one shaft portion.
First, referring to FIG. 1, the telescopic shaft has a male spline 5 which engages with the female spline 3 in a fitting hole 4 having a female spline 3 formed at an end 2 of the outer shaft portion 1. It is configured by inserting the end 7 of the inner shaft 6.
[0015]
A male spline 5 is formed on the outer periphery of the end portion 7 of the inner shaft portion 6, and the male spline 5 has two male splines 5 a, located on both sides of a reduced diameter portion 8 having a predetermined width in the axial direction. 5b.
In FIG. 1, the male splines 5a and 5b and the female splines 3 are schematically shown. A rattling preventing member 9 made of an elastic body is mounted on the reduced diameter portion 8. The backlash preventing member 9 is formed by press forming a sheet metal material.
[0016]
Referring to FIGS. 1, 2 and 3, this backlash prevention member 9 includes a pair of legs 10 and 11 that extend and bend in the circumferential direction P <b> 1 (see FIG. 3) of reduced diameter portion 8, and a pair of these legs 10 and 11. And a connecting portion 12 for connecting between the opposed one end portions 10a and 11a of the leg portions 10 and 11.
Referring to FIG. 3, rattling preventing member 9 extends from connecting portion 12 in a direction P <b> 2 substantially in the same direction as legs 10, 11, and is curved. An elastic pressing piece portion (13) for elastically pressing the female spline (3) of the shaft portion (1) is provided.
[0017]
The pair of legs 10, 11 and the connecting portion 12 are formed to have the same curvature, that is, to be bent in the same direction with the same radius of curvature R (corresponding to the radius of the reduced diameter portion 8).
On the other hand, as shown in FIG. 3, the elastic pressing piece 13 may have the same curvature as the legs 10, 11, for example. That is, the radius of curvature R1 of the elastic pressing piece 13 is equal to the radius of curvature R of the legs 10 and 11 (R1 = R), and the center of curvature C1 of the elastic pressing piece 13 is from the center of curvature C of the legs 10 and 11. The offset may be offset by a predetermined amount d.
[0018]
Further, the radius of curvature R1 of the elastic pressing piece 13 may be larger than the radius of curvature R of the legs 10, 11 (R1> R).
FIG. 4 shows an intermediate body 90 for manufacturing the backlash preventing member 9 formed of sheet metal, which is in a developed shape. The leg-forming portions 100 and 110 extending in parallel with each other and the connecting-portion forming portion 120 form a U-shape, and the elastic pressing piece portion is formed from the connecting-portion forming portion 120 in parallel with the leg-forming portions 100 and 110. An extension 130 extends. The backlash preventing member 9 is formed by bending the respective parts 100, 110, 120, and 130 of the manufacturing intermediate 90 in the same direction.
[0019]
According to the present embodiment described above, a part of the inner shaft portion 6 is pressed against the corresponding portion of the outer shaft portion 1 by the pressing reaction force received by the elastic pressing piece portion 13 of the play prevention member 9 from the female spline 3. Therefore, the backlash in the radial direction of the two shaft portions 1 and 6 can be killed, and abnormal noise caused by the backlash can be suppressed.
The legs 10 and 11 for holding the reduced diameter portion 8 of the inner shaft 6 and the elastic pressing piece 13 for elastically pressing the female spline 3 of the outer shaft 1 are substantially in the same directions P1 and P2. Since the legs 10 and 11 and the elastic pressing piece 13 are bent in the same direction because they are stretched and curved. As a result, the manufacturing process is simplified, and the manufacturing cost can be reduced.
[0020]
Further, since the pair of legs 10, 11 and the connecting portion 12 are bent in the same direction with the same curvature, the pair of legs 10, 11 and the connecting portion 12 can be bent and formed collectively. Costs can be reduced.
Further, by simply changing the curvature and the center of curvature of the elastic pressing piece 13 with respect to the legs 10 and 11 bent in the same direction, the pressing load of the elastic pressing piece 13 can be easily set, and the load tuning can be performed. Easy. Note that tuning can be performed by changing the thickness, shape, size, and the like of the play prevention member 9, particularly the elastic pressing piece 13.
[0021]
5 and 6 show another embodiment of the present invention. Referring to these figures, the present embodiment mainly differs from the embodiment of FIG. 1 in that a play preventing member 9A that can also prevent play in the rotation direction of both shaft portions 1 and 6 is used. On the point.
That is, the backlash preventing member 9A forms the engaging projections 14 as the engaging portions which are bent inward at substantially right angles at the tip portions 10b and 11b as the other end portions of the leg portions 10 and 11, respectively. Engagement projections 15 are formed on the edge 12a of the connecting portion 12 opposite to the distal ends 10b, 11b of the legs 10, 11, respectively, as engagement portions bent inwardly in a curved manner.
[0022]
As shown in FIG. 6, each of the engaging projections 14, 15 engages with engaging grooves 16, 17 formed on the surface of the reduced diameter portion 8 of the inner shaft portion 6, while the distal end of the elastic pressing piece portion 13 is engaged. The relative rotation of the two shaft portions 1 and 6 can be restricted by engaging the portion 13a with the valley portion 3a of the female spline 3 of the outer shaft portion 1.
Specifically, the elastic force of the elastic pressing piece 13 acts to twist the inner shaft 1 and the outer shaft 6 in opposite directions, so that the elastic pressing piece 13 moves in the circumferential direction of the two shafts 1 and 6. , The teeth of the corresponding male and female splines 3, 5 of the both shaft portions 1, 6 are pressed in the rotation direction, and thereby the play of the both shaft portions 1, 6 in the rotation direction is reduced. By doing so, it is possible to suppress the occurrence of abnormal noise accompanying this.
[0023]
In FIG. 6, the radius of curvature R1 of the elastic pressing piece 13 is larger than the radius of curvature R of the legs 10, 11 and the connecting portion 12 (R1> R). The engagement protrusion 15 may be a single protrusion extending over the entire edge 12a of the connection portion 12, or a plurality of protrusions arranged at predetermined intervals on the edge 12a of the connection portion 12. good. In addition, one of the engagement projections 14 and 15 can be omitted.
The present invention is not limited to the above embodiments. For example, at least one of the male spline 5 or the female spline 3 is provided with a film coated with a synthetic resin having a low friction coefficient such as a fluororesin. You may do it. In this case, the sliding resistance between the splines 3 and 5 can be reduced by the coating of the synthetic resin. In particular, since the clearance between the splines 3 and 5 is reduced by the synthetic resin film and the rattling sound is prevented in cooperation with the rattling preventing member 9 made of an elastic member, the rattling preventing effect is very high. This can be achieved at low cost.
[0024]
The telescopic shaft of the present invention is used not only as a steering shaft, but also as an intermediate shaft for connecting the steering shaft to a steering mechanism such as a rack and pinion mechanism. In addition, various changes can be made within the scope of the claims of the present invention.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view of a telescopic shaft according to an embodiment of the present invention.
FIG. 2 is a schematic side view of an inner shaft portion on which a play preventing member is mounted.
FIG. 3 is a schematic cross-sectional view of a main part of a telescopic shaft, showing a mounted state of a backlash prevention member.
FIG. 4 is a plan view of an intermediate for manufacturing a play preventing member.
FIG. 5 is an exploded perspective view of a telescopic shaft according to another embodiment of the present invention.
FIG. 6 is a schematic cross-sectional view of a main part of a telescopic shaft, showing a mounted state of a play preventing member in the embodiment of FIG.
FIG. 7 is an exploded perspective view of a conventional telescopic shaft.
FIG. 8 is a perspective view of a conventional backlash preventing member.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Outer shaft part 3 Female spline 3a Valley part 4 Fitting hole 5 Male spline 5a, 5b Male spline 6 Inner shaft part 8 Reduced diameter part 9, 9A Anti-rattle member 10, 11, Leg 10a, 11a One end (opposed end) )
10b, 11b Tip part 12 Connecting part 12a Edge part 13 Elastic pressing piece part 13a Tip part 14, 15 Engagement projection (engagement part)
16, 17 engagement groove

Claims (3)

A female spline is formed by inserting an inner shaft portion having an axially formed male spline engaged with the female spline into a fitting hole of an outer shaft portion having an axially formed female spline. In a telescopic shaft that has a diameter part and axially divides the male spline,
A play preventing member made of an elastic body is arranged at the reduced diameter portion,
The backlash preventing member includes a pair of legs that extend and bend in the circumferential direction of the reduced diameter portion, a connecting portion that connects between the opposing ends of the pair of legs, and a connecting portion that is substantially the same as the leg. And a resilient pressing piece which resiliently presses the female spline of the outer shaft portion outside the curve than the leg portion. 2. The engaging portion according to claim 1, wherein the engaging portion provided on at least one of the distal end portion of the leg portion or the edge portion of the connecting portion on the opposite side engages with the engaging groove provided on the reduced diameter portion of the inner shaft portion. And a distal end portion of the elastic pressing piece portion is engaged with a valley portion of the female spline of the outer shaft portion. 3. The telescopic shaft according to claim 1, wherein the pair of legs and the connecting portion are formed to have the same curvature and bend in the same direction.

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