JP2001182736A - Freely extendable shaft - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a freely extendable shaft composed of a pair of serration engaged shaft which is easy to assemble and is free of backlashes. SOLUTION: An elastic plate 9 is fixed by spot welding to a flat recess 8, formed by cutting off serration gear teeth in partial area of male serration 5 in the longitudinal and the circumferential direction. The elastic plate 9 has a fixed part 11, placed firmly on the recess 8 and an extensional part 12 formed as an extension starting from the edge of the fixed part 11. The apex of the extension part 12 constitutes a contact part 13 which presses a female serration resiliently.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a telescopic shaft having a structure for preventing backlash (misalignment) of a serration connection.

[0002]

2. Description of the Related Art The above-mentioned telescopic shaft is used, for example, as a steering intermediate shaft of an automobile. That is, it is used for adjusting the length of the intermediate shaft for absorbing the relative displacement between the steering and the column when the vehicle is running, or for adjusting the length of the intermediate shaft during assembly. Generally, a spline or serration (hereinafter referred to as serration) fitting method is employed.

[0003] In the serration fitting method, a fitting hole having a female serration formed in the end of the first shaft is provided.
The ends of a second shaft having a male serration that engages with the female serrations are inserted to connect the two shafts so as to be integrally rotatable. In order to facilitate assembly, it is preferable to increase the clearance between the male serration and the female serration. In this case, however, the clearance is disturbed, and backlash (misalignment) occurs between both shafts.
The rattling noise causes discomfort to the driver. On the other hand, when the above clearance is reduced, it becomes difficult to insert and remove the second shaft into and from the fitting hole.

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 which is easy to assemble and has a high rattling prevention effect after assembling.

[0005]

Means for Solving the Problems and Effects of the Invention In order to achieve the above object, the invention according to claim 1 is characterized in that a fitting hole having a female serration formed at an end of a first shaft is provided.
In a telescopic shaft formed by inserting an end of a second shaft having a male serration engaged with the female serration, a concave portion formed by lacking at least serration teeth in a part of a circumferential direction of the male serration. When,
An elastic body held in the recess by welding or engagement and elastically in contact with the female serration is provided.

According to the present invention, since the play between the two shafts can be eliminated by the elastic body, generation of abnormal noise due to vibration or the like can be prevented. Further, since the elastic body is held in the concave portion of the male serration, when the two shafts are fitted together, the elastic body does not shift and the assembly is easy. Further, since the region for forming the concave portion is limited to a part of the circumferential direction of the male serration, the function of the serration connection does not decrease, and therefore, the fitting length does not need to be lengthened unnecessarily.

[0007] When the recess is flat, the elastic body can be stably held, which is also preferable for preventing backlash. Also,
When forming a recess only by lacking serrated teeth,
It is only necessary to form a concave portion due to a missing tooth at the time of forming the serration, and post-processing is not required, so that manufacturing cost can be reduced. The invention according to claim 2 is based on claim 1,
The elastic body is provided with a pair of holding ends fitted and held in cutout grooves formed respectively at opposite ends of the recess, and a female serration tooth provided at an intermediate portion between the pair of holding ends. It is characterized by comprising a leaf spring including a curved contact portion which elastically contacts the tip portion. According to the present invention, the same operation and effect as those of the invention described in claim 1 are obtained. Further, the elastic body can be securely held in the concave portion by a simple structure in which the holding end of the elastic body is simply fitted into the notch grooves at both ends of the concave portion.

According to a third aspect of the present invention, in the first aspect, the concave portion has a round shape as viewed in a radial direction of the second shaft, and the elastic body has an elasticity on a wall surrounding the concave portion. , And a leaf spring including a curved contact portion supported by the leg portion and elastically contacting the tooth tip of the female serration. According to the present invention, the same operation and effect as those of the invention described in claim 1 are obtained. Furthermore, the elastic body can be reliably held in the concave portion with a simple structure in which the elastic body is simply fitted into the round concave portion.

According to a fourth aspect of the present invention, an end of a second shaft having a male serration which engages with the female serration is inserted into a fitting hole having a female serration formed at an end of the first shaft. In the telescopic shaft that is inserted, a pair of male and female serration teeth opposed to each other is formed between a pair of recesses formed by lacking teeth in a part of the circumferential direction of the male and female serrations. A space defined by the side surfaces, and in a state accommodated in the space, at least one of the pair of recesses and the pair of side surfaces is elastically pressed to radially move the first and second shafts. And a wave spring for preventing at least one backlash in the circumferential direction.

According to the present invention, the two shafts can be assembled in a state where the wave spring is held in the concave portion formed of the missing tooth region, so that the assembly is easy. In addition, if the wave spring is used, sufficient elasticity is exhibited, and it is possible to prevent the backlash in one or both of the radial direction and the circumferential direction of the shaft, and the backlash preventing effect is high. Moreover,
Since the missing tooth region for forming the concave portion is limited to a part of the circumferential direction of the male serration, the function of the serration connection does not decrease, and therefore, the fitting length does not need to be lengthened unnecessarily. Furthermore, it is only necessary to form missing teeth when forming serrated teeth, and post-processing is not required, so that manufacturing costs can be reduced.

According to a fifth aspect of the present invention, in the fourth aspect, a rod-shaped elastic resin is used instead of the wave spring. If it is a rod-shaped elastic resin, it can be pressed in a state where the contact area with the pair of recesses and the pair of side surfaces is widened, and stable pressing is possible,
The play prevention effect can be enhanced.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described with reference to the accompanying drawings. 1 is a perspective view of one shaft of the telescopic shaft according to the first embodiment of the present invention, FIG. 2 is a partially cutaway side view of the telescopic shaft, and FIG. 3 is a cross-sectional view of the telescopic shaft. It is. Referring to FIG. 2, this telescopic shaft has a fitting hole 4 having a female serration 3 formed at end 2 of first shaft 1.
A male serration 5 engaging with the female serration 3
It is configured by inserting the end 7 of the second shaft 6 having

Referring to FIGS. 1 and 2, a concave portion 8 formed of a flat portion is formed in a part of the second shaft 6 in the axial direction and the circumferential direction of the male serration 5. Recess 8
It is sufficient that at least a part of the above-mentioned area is formed without serration teeth, but in the present embodiment, the land part of the serration tooth is also omitted, and the cross section of the second shaft 6 including the recess 8 is formed. It is designed to be D-shaped. An elastic body 9 as a play preventing member is attached to the recess 8. That is, the elastic body 9 is formed of a leaf spring having a rectangular shape in a plan view, and has a fixing portion 11 along the flat concave portion 8 and fixed to the concave portion 8 by the spot welding portion 10, and forms a mountain shape from one end of the fixing portion 11. Extension part 1
2 is provided. As shown in FIG. 3, the top of the extending portion 12 forms a curved contact portion 13 that elastically contacts the tooth tip of the female serration 3. The cross section of the contact portion 13 is curved so as to form a mountain shape (for example, an arc shape).
This is to cope with the circumferential curvature of the female serration 3.

In this embodiment, since the play between the shafts 1 and 6 can be eliminated by the elastic body 9, generation of abnormal noise due to vibration or the like can be prevented. Further, since the elastic body 9 is fixed to the concave portion 8 of the male serration 5, when the shafts 1 and 6 are fitted together, the elastic body 9 does not shift and is easy to assemble. Also, the recess 8
Is provided only in a part of the circumferential direction of the male serration 5, so that the function of the serration connection does not decrease, and therefore, the fitting length does not need to be lengthened unnecessarily.
As a result, downsizing of the telescopic shaft can be achieved.

Further, since the concave portion 8 is flat, the elastic body 9 can be stably held, and as a result, the backlash preventing effect is high. In addition, the concave portion 8 may be formed only by lacking the serration teeth. In this case, the concave portion due to the missing tooth may be formed at the time of forming the serration, and post-processing is unnecessary, so that the manufacturing cost can be reduced. Next, FIGS. 4A and 4B show a second embodiment of the present invention. Referring to FIG. 4, the configuration of this embodiment different from the embodiment of FIG.
In the embodiment of FIG. 1, the elastic body 9 for preventing backlash is fixed by spot welding, whereas in the present embodiment, the elastic body 9A is provided with the cutout grooves 14 provided at both ends of the recess 8. And fixed.

That is, the elastic body 9A is formed of a rectangular flat plate in plan view having a mountain-shaped curved portion at the center. Recess 8
Notch grooves 14 are formed at a pair of ends facing each other along the axial direction of the elastic member 9. A pair of holding ends 15, 15 of the elastic body 9 </ b> A are fitted into the corresponding notch grooves 14. Is held. An intermediate portion between the pair of holding ends 15 of the elastic body 9A is provided with a mountain-shaped curved portion 16 which elastically contacts the tooth tip of the female serration 3, and a top portion of the curved portion 16 is provided. The contact portion 17 for pressing the female serration 3 is formed by the above.

The holding ends 15, 15 of the elastic body 9A are
Notch 1 along the corresponding opposite end walls 18, 18.
When the elastic body 9A is introduced into the space 4, the elastic body 9A is elastically deformed into a substantially rectangular shape so as to shorten the interval between the pair of holding ends 15, 15. The above-mentioned notch grooves 14 are provided at the lower end of the opposed end wall 18, respectively, and the upper wall surface of the notch groove 14 is formed as an inclined guide surface for facilitating the introduction of the holding end 15. According to the present invention, the same operation and effect as those of the invention described in claim 1 are obtained. Furthermore, the elastic body 9A can be securely held in the recess 8 with a simple structure in which the holding end 15 of the elastic body 9A is simply fitted into the cutout grooves 14 at both ends of the recess 8, and the assembling property is good. .

Next, FIGS. 5 to 7 show a third embodiment of the present invention. Referring to FIG. 5, in the present embodiment, the second serration 5 of the second shaft 6 is
A concave portion 19 which is circular when viewed along the radial direction of the shaft 6
The elastic body 20 is accommodated and held in the concave portion 19. The periphery of the recess 19 is a wall surface 21
As shown in FIGS. 5 and 6A, the elastic body 20 includes a pair of legs 22 that are elastically fitted into the wall surface 21. A pair of legs 2
Bowl-shaped part 2 that connects the central part between
3 is provided, and by the top of the bowl-shaped portion 23,
As shown in FIG. 6 (b) and FIG.
The contact part 24 which elastically contacts the tooth tip part 3a of this is comprised. That is, the contact portion 24 is supported by the concave portion 19 by the pair of leg portions 22, 22.

According to the present invention, the same functions and effects as those of the first aspect are obtained. Furthermore, with a simple structure in which the elastic body 20 is simply fitted into the round recess 19,
The elastic body 20 can be securely held in the concave portion 19, and the assembling property is good. Next, FIGS. 8 and 9 show a fourth embodiment of the present invention. Referring to FIG. 8, in the present embodiment, a pair of concave portions 2 formed without teeth is formed in a part of the circumferential direction of female serration 3 and male serration 5.
5 and 26 are radially opposed to each other.
Between 26, teeth 3 of opposite male and female serrations 3,5
A space 27 is defined by a pair of side surfaces 3b and 5b of the a and 5a. A wave spring 28 is housed in this space 27.

As shown in FIG. 9, the wave spring 28 is
7, the shafts 1 and 6 have a shape that undulates in both the circumferential direction and the radial direction. This allows
The wave spring 28 elastically presses the pair of recesses 25, 26 and the side surfaces 3b, 5b of the pair of teeth 3a, 5a,
The play in the radial and circumferential directions between the first and second shafts 1 and 6 can be prevented, and the play prevention effect is very high. As shown in FIG. 8, in a state where the second shaft 6 is pulled out, a wave spring 28 is provided between the side surfaces 5b of the pair of male serration teeth 5a circumferentially opposed to each other with the concave portion 26 interposed therebetween. If the shafts 1 and 6 are fitted together, the wave spring 28 can be held in the concave portion 26 of the male serration 5 when the shafts 1 and 6 are fitted to each other, so that the assembly is easy.

Also, in place of the above-mentioned wave spring 28, FIG.
As shown in FIG. 0, a rod-shaped elastic resin 29 may be used. In this case, the elastic resin 29 is provided between the pair of recesses 25 and 2.
6 and the pair of side surfaces 3b, 5b can be pressed in a state where the contact area is widened, and stable pressing is possible,
The play prevention effect can be enhanced. Note that an elastic rubber may be used instead of the elastic resin. In addition, the present invention is not limited to the above embodiments, and various changes can be made within the scope of the present invention.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a second shaft of a telescopic shaft according to a first embodiment of the present invention.

FIG. 2 is a partially cutaway side view of the telescopic shaft.

FIG. 3 is a sectional view of a telescopic shaft.

FIG. 4A is a side view of a second shaft,
(B) is a plan view of the elastic body.

FIG. 5 is an exploded perspective view of a main part of a telescopic shaft according to a second embodiment of the present invention.

6 (a) is a plan view of an elastic body used for the telescopic shaft of FIG. 5, and FIG. 6 (b) is a cross-sectional view of the telescopic shaft cut along the axial direction of the shaft.

FIG. 7 is a cross-sectional view taken along a plane orthogonal to the axial direction of the telescopic shaft of FIG.

FIG. 8 is an exploded perspective view of a main part of a telescopic shaft according to a third embodiment of the present invention.

FIG. 9 is a sectional view of the telescopic shaft of FIG. 8;

FIG. 10 is a sectional view of a telescopic shaft according to a fourth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st shaft 2 End part 3 Female serration 3a, 5a Teeth 3b, 5b Side surface 4 Fitting hole 5 Male serration 6 Second shaft 7 End part 8, 19, 25, 26 Concave part 9 Elastic body 10 Welded part 13 Contact Part 14 Notch groove 15 Holding end part 17 Contact part 20 Elastic body 22 Leg part 24 Contact part 27 Void 28 Wave spring (elastic body) 29 Elastic resin (elastic body)

Continued on the front page (72) Inventor Junya Watanabe 3-5-8 Minamisenba, Chuo-ku, Osaka Koyo Seiko Co., Ltd. F-term (reference) 3D030 DC22 DC40 DD61 3J033 AA01 AB01 AB03 BA02 BA08

Claims (5)

[Claims] 1. An extensible and retractable structure in which an end of a second shaft having a male serration engaged with the female serration is inserted into a fitting hole having a female serration formed at an end of the first shaft. A shaft having a concave portion formed by lacking at least serration teeth in a part of the male serration in the axial direction and a part of the circumferential direction; an elastic portion which is retained by welding or engagement in the concave portion and elastically contacts the female serration; A telescopic shaft comprising a body. 2. The elastic body is provided at a pair of holding ends fitted and held in cutout grooves respectively formed at opposing ends of the recess, and at an intermediate portion between the pair of holding ends. 2. A leaf spring including a curved contact portion which elastically contacts a tooth tip of a female serration.
The telescopic shaft as described. 3. The concave portion has a round shape as viewed along the radial direction of the second shaft, and the elastic body has a leg portion elastically fitted on a wall surrounding the concave portion, and the leg portion. 2. A telescopic shaft according to claim 1, comprising a leaf spring including a curved contact portion supported by the elastic member and elastically contacting the tooth tip of the female serration. 4. An extendable and retractable structure wherein an end of a second shaft having a male serration engaged with the female serration is inserted into a fitting hole having a female serration formed at an end of the first shaft. In the shaft, an empty space defined by a pair of side surfaces of opposing male and female serration teeth between a pair of concave portions formed without teeth in a part of a circumferential direction of the male and female serrations. And at least one of the pair of recesses and the pair of side surfaces is elastically pressed in a state of being accommodated in the space, and at least one of the radial direction and the circumferential direction of the first and second shafts. A telescopic shaft comprising: a wave spring for preventing backlash. 5. A telescopic shaft according to claim 4, wherein a rod-shaped elastic resin is used in place of said wave spring.