JP2004306919A - Telescopic shaft for vehicle steering - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a telescopic shaft for vehicle steering free from backlash in rotational directions, capable of transmitting a torque in a high rigid state, having an excellent life and having a low cost. <P>SOLUTION: A torque transmission member 7, which is rolled in relative movement in a shaft direction, is disposed between a plurality of pairs of axial grooves 3, 5 provided respectively on an outer circumferential face of a male shaft 1 and an inner circumferential face of a female shaft 2. Regarding the diameter of the outer circumferential face of the male shaft 1, there are a part, which is passed through the rolling center of the torque transmission member 7 and has a larger diameter than a ball pitch circle 10, and a part, which has a smaller diameter than the ball pitch circle 10, are alternately formed with the axial groove 3 being sandwiched therebetween. At the same time, in the diameter of the inner circumferential face of the female shaft 2, according to the size of the outer diameter of the male shaft 1, a part, which has a larger diameter than the ball pitch circle 10, and a part, which has a smaller diameter than the ball pitch circle 10, are alternately formed with the axial groove 5 being sandwiched therebetween. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a telescopic shaft for a vehicle steering, which is incorporated in a steering shaft of a vehicle and in which a male shaft and a female shaft are non-rotatably and slidably fitted to each other.
[0002]
[Prior art]
Conventionally, telescopic shafts for vehicle steering in the steering mechanism of automobiles have the ability to absorb the axial displacement that occurs when the automobile travels and to prevent the displacement and vibration from being transmitted to the steering wheel. There is also a need for a function that adjusts the axial position of the steering wheel in order to obtain the optimal position for the driver to drive the car.
[0003]
Therefore, the telescopic shaft for vehicle steering is required to have a function of expanding and contracting in the axial direction. In any of the above cases, the telescopic shaft is required to reduce rattling. Under these circumstances, conventionally, the male shaft is coated with a nylon film and the sliding part is coated with grease to absorb or reduce metal noise and metal tapping noise, and to reduce the sliding resistance in the axial direction. , And the play of the shaft in the rotation direction has been reduced.
[0004]
However, as the abrasion of the nylon film progresses due to aging, play in the rotational direction increases. In particular, under the condition of being exposed to high noise in the engine room, the volume of the nylon film changes, the sliding resistance becomes extremely large, and the wear is remarkably accelerated, so that the rattling in the rotating direction is further increased. There was a problem.
[0005]
Therefore, in Patent Document 1, a torque transmitting member (for example, spherical) that is disposed between the outer peripheral surface of the male shaft and the inner peripheral surface of the female shaft and rolls when the male shaft and the female shaft move in the axial direction relative to each other. And an elastic body disposed radially adjacent to the torque transmitting member and applying a preload to the male shaft and the female shaft via the torque transmitting member. . With this configuration, a stable sliding load is realized, rattling is reliably prevented, and torque can be transmitted in a highly rigid state.
[0006]
[Patent Document 1]
German Patent DE 37 30 393 C2
[Problems to be solved by the invention]
However, the conventional telescopic shaft for vehicle steering has a problem that the number of parts increases and the cost increases because the elastic body is provided to apply a preload to the male shaft and the female shaft via the torque transmitting member. There was a point.
[0008]
In addition, if a leaf spring or the like is used for the elastic body in order to reliably prevent backlash in the rotating direction and achieve a high rigidity state, high stress is generated in the leaf spring, which is permanently deformed and causes torsional rigidity. However, there is a problem that the temperature is reduced.
[0009]
The present invention improves the disadvantages of the conventional example described above, can reliably prevent backlash in the rotating direction of the male shaft and the female shaft, can transmit torque in a highly rigid state, and has excellent durability. It is an object of the present invention to provide a low-cost telescopic shaft for vehicle steering.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, a telescopic shaft for a vehicle steering in which a male shaft and a female shaft are fitted in a steering shaft of a vehicle such that the male shaft and the female shaft are non-rotatably and slidably fitted to each other, A torque transmitting member that rolls when the two shafts move relative to each other in the axial direction is disposed between a plurality of pairs of axial grooves formed on the inner surface of the female shaft and the inner circumferential surface of the female shaft, respectively. The outer diameter of the surface is configured such that a portion larger than a ball pitch circle diameter passing through the rolling center of the torque transmitting member and a portion smaller than this are formed alternately with the axial groove interposed therebetween. In addition, the inner diameter of the inner peripheral surface of the female shaft is larger or smaller than the ball pitch circle diameter according to the outer diameter of the male shaft. It is characterized by being formed alternately.
[0011]
With the above configuration, at the time of torque transmission, the surface (inner edge) of the axial groove of the male shaft on the side of the portion larger than the ball pitch circle diameter and the axial groove of the female shaft facing this groove Since the torque transmission member is constrained in the circumferential direction by the surface (inner edge) of the portion smaller than the ball pitch circle diameter, the rigidity in the rotational direction between the male shaft and the female shaft is improved, and high rigidity is achieved. In this state, torque can be transmitted, and rattling in the rotational direction between the male shaft and the female shaft can be prevented.
[0012]
In addition, since pressurization can be applied in the shaft rotation direction only by the male shaft, the female shaft, and the torque transmitting member, an elastic body for applying pressurization can be omitted.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a telescopic shaft for vehicle steering according to an embodiment of the present invention will be described with reference to the drawings.
[0014]
(Overall configuration of vehicle steering shaft)
FIG. 5 is a side view of a steering mechanism of an automobile to which the telescopic shaft for vehicle steering according to the embodiment of the present invention is applied.
[0015]
In FIG. 5, an upper steering shaft portion 120 (a steering column 103 and a swirling shaft 104 rotatably held by the steering column 103 are attached to a vehicle body side member 100 via an upper bracket 101 and a lower bracket 102). ), A steering wheel 105 mounted on the upper end of the steering shaft 104, a lower steering shaft portion 107 connected to a lower end of the steering shaft 104 via a universal joint 106, and a steering shaft joint 108 connected to the lower steering shaft portion 107. , A steering rack shaft 112 connected to the pinion shaft 109, and an elastic frame mounted on another frame 110 of the vehicle body by supporting the steering rack shaft 112. Steering mechanism from a fixed steering rack support member 113 via 111 is formed.
[0016]
Here, the upper steering shaft portion 120 and the lower steering shaft portion 107 use the telescopic shaft for vehicle steering (hereinafter referred to as the telescopic shaft) according to the embodiment of the present invention. The lower steering shaft portion 107 is formed by fitting a male shaft and a female shaft. The lower steering shaft portion 107 absorbs an axial displacement generated when a vehicle travels, and is provided with a steering wheel. A performance that does not transmit the displacement or vibration on the surface 105 is required. In such a performance, the vehicle body has a sub-frame structure, and the member 100 for fixing the upper part of the steering mechanism and the frame 110 on which the steering rack support member 113 is fixed are separate bodies. This is required in the case of a structure fastened and fixed to the frame 110 via an elastic body 111 such as rubber. Further, as another case, when fastening the steering shaft joint 108 to the pinion shaft 109, the operator may need to first contract the telescopic shaft and then fit and fasten to the pinion shaft 109 so that the telescopic function is required. . Further, the upper steering shaft portion 120 at the upper part of the steering mechanism is also one in which a male shaft and a female shaft are fitted. However, such an upper steering shaft portion 120 is used for driving a car by a driver. In order to obtain the optimal position, a function of moving the position of the steering wheel 105 in the axial direction and adjusting the position is required, so that a function of expanding and contracting in the axial direction is required. In all the above cases, the telescopic shaft is required to reduce rattling noise of the fitting portion, reduce rattling on the steering wheel 105, and reduce sliding resistance when sliding in the axial direction. Required.
[0017]
(1st Embodiment)
FIG. 1 is a radial cross-sectional view of a vehicle steering telescopic shaft according to a first embodiment of the present invention, FIG. 2 is a vertical cross-sectional view of the vehicle steering telescopic shaft of FIG. 1, and FIG. 3 is a female shaft of FIG. FIG. 4 is a radial sectional view showing the male shaft of FIG.
[0018]
First, a first embodiment will be described with reference to FIGS. As shown in FIG. 2, the telescopic shaft for vehicle steering is composed of a male shaft 1 and a female shaft 2 which are non-rotatably and slidably fitted to each other.
[0019]
As shown in FIG. 1, six axial grooves 3 are formed on the outer peripheral surface of the male shaft 1 so as to be parallel to each other in the axial direction. Six axial grooves 5 are formed on the inner peripheral surface of the female shaft 2 at positions facing these axial grooves 3 so as to be parallel to each other in the axial direction. Between these six pairs of axial grooves 3, 5, spherical bodies 7, which are a plurality of torque transmitting members that roll when the two shafts move relative to each other in the axial direction, are interposed. Further, as shown in FIG. 2, these spherical bodies 7 are prevented from coming off the axial grooves 3 and 5 by a retaining ring 11 provided at the end of the male shaft 1.
[0020]
The diameter of the spherical body 7 is designed so that an appropriate pressurization is generated, and in order to improve the assembling property, the effective support of the central portion is set in the length direction of the axial grooves 3 and 5 at the bottom of the groove. A curved portion that is gently curved outward is formed at the groove end excluding the portion. In this embodiment, the spherical body 7 is used as the torque transmitting member, but the present invention is not limited to this, and a roller may be used.
[0021]
As shown in FIG. 1, assuming that six pairs of axial grooves 3, 5 are A, B, C, D, E, F, and the center of the male shaft 1 is O, the inner circumference of the female shaft 2 is The arrangement angle pattern of the axial groove 5 adjacent to the surface is
∠AOB = ∠BOC = ∠COD = ∠DOE = ∠EOF = ∠FOA = 60 °
It is. However, ∠AOB or the like means an arc angle with respect to the axis O of each arc center point of the cross-sectional shape of the axial groove 5 of the female shaft 2.
[0022]
On the other hand, the arrangement angle pattern of the axial grooves 3 adjacent to the outer peripheral surface of the male shaft 1 is as follows.
∠AOB = ∠COD = ∠EOF = 58 °
∠BOC = ∠DOE = ∠FOA = 62 °
It is. However, ∠AOB or the like means an arc angle with respect to the axis O of each arc center point of the cross-sectional shape of the axial groove 3 of the male shaft 1. As described above, the arrangement angle patterns of the axial grooves 3 adjacent to the male shaft 1 are different, and when 62 ° is large and 58 ° is small, small → large → small → large → small → large. I have.
[0023]
As shown in FIG. 3, the inner diameter of the inner peripheral surface of the female shaft 2 is larger than the diameter of a ball pitch circle 10 (indicated by a dashed line) passing through the rolling center of the spherical body 7, and The small portion a has a configuration in which a pattern formed alternately with the axial groove 5 interposed therebetween is continuous.
[0024]
Similarly, the outer diameter of the outer peripheral surface of the male shaft 1 is, as shown in FIG. 4, a portion b larger than the ball pitch circle 10 diameter of the spherical body 7 in accordance with the inner diameter of the female shaft 2. The smaller portion has a configuration in which a pattern formed alternately with the axial groove 3 interposed therebetween is continuous.
[0025]
As described above, the minimum inner diameter a of the female shaft 2 is set smaller than the ball pitch circle 10, and the maximum outer diameter b of the male shaft 1 is set larger than the ball pitch circle 10. That is, the maximum outer diameter b of the male shaft 1 is larger than the minimum inner diameter a of the female shaft 2.
[0026]
A portion b of the inner diameter of the female shaft 2 which is larger than the ball pitch circle diameter 10 is opposed to a portion b in which the adjacent axial groove 3 of the male shaft 1 is disposed at a large angle and the outer diameter of which is larger than the ball pitch circle diameter 10. In the portion a of the inner diameter of the female shaft 2 smaller than the ball pitch circle diameter 10, the arrangement angle of the adjacent axial groove 3 of the male shaft 1 is small, and the outer diameter thereof is smaller than the ball pitch circle diameter 10. Are facing each other.
[0027]
In the above configuration, when torque is not transmitted (sliding), as shown in FIG. 1, the axial groove 3 on the male shaft 1 and the axial groove 5 on the female shaft 2 have different arrangement angle patterns. And the maximum outer diameter b of the male shaft 1 is set to be larger than the minimum inner diameter a of the female shaft 2, so that the spherical body 7 and the axial groove 3, 5 are pressed against each other and are elastically deformed, so that rattling in the rotational direction between the male shaft 1 and the female shaft 2 can be reliably prevented. At the same time, the male shaft 1 and the female shaft 2 can slide in the axial direction with a stable sliding load without rattling.
[0028]
On the other hand, when transmitting torque, the arrangement angle patterns of the adjacent axial grooves 3 and 5 of the male shaft 1 and the female shaft 2 are different, and the maximum outer diameter b of the male shaft 1 is set larger than the minimum inner diameter a of the female shaft 2. As a result, the spherical body 7 can be restrained in the circumferential direction. Therefore, it is possible to reliably prevent rattling in the rotational direction between the male shaft 1 and the female shaft 2 and transmit torque in a highly rigid state.
[0029]
In the present embodiment, in addition to the difference in the arrangement angle pattern of the axial grooves 3 adjacent to the male shaft 1, in particular, the maximum outer diameter b of the male shaft 1 is larger than the ball pitch circle 10, 2 is smaller than the ball pitch circle 10.
[0030]
In the configuration of the present embodiment, as shown in FIG. 1, the arrow indicating the contact force between the spherical body 7 and the axial grooves 3 and 5 substantially coincides with the circumferential direction (the direction of the ball pitch circle 10). This is because the inner groove 3a of the axial groove 3 of the male shaft 1 on the side larger than the diameter of the ball pitch circle 10 and the diameter of the ball pitch circle 10 of the axial groove 5 of the female shaft 2 opposed to the groove 3 are formed. This is because the spherical body 7 is constrained in the circumferential direction by the inner edge portion 5a on the smaller side.
[0031]
By this effect, in the present embodiment, the rigidity in the rotational direction between the male shaft 1 and the female shaft 2 can be improved, and the torque can be transmitted with a higher rigidity.
[0032]
Next, a second embodiment will be described with reference to FIGS.
6 is a radial cross-sectional view of a telescopic shaft for vehicle steering showing a second embodiment, FIG. 7 is a radial cross-sectional view showing a female shaft of FIG. 6, and FIG. 8 is a radial cross-sectional view showing a male shaft of FIG. It is.
[0033]
This embodiment is substantially the same as the first embodiment, and the same members are denoted by the same reference numerals and overlapping description will be omitted. What is different is that for the axial grooves B and C, D and E, and F and A of the female shaft 2, the inner diameter of the portion sandwiched between the respective grooves 5 and the maximum inner diameter of the groove bottom coincide. The point is Similarly, for the axial grooves A and B, C and D, and E and F of the male shaft 1, the outer diameter of the portion sandwiched between the respective grooves 3 and the minimum outer diameter of the groove bottom are made to match. ing.
[0034]
7 and 8, the minimum inner diameter a of the female shaft 2 is smaller than the ball pitch circle 10 and the maximum outer diameter b of the male shaft 1 is smaller than the ball pitch circle 10, as in the first embodiment. It is getting bigger. That is, the maximum outer diameter b of the male shaft 1 is larger than the minimum inner diameter a of the female shaft 2.
[0035]
Also in this configuration, the ball pitch circle of the inner groove 3b of the axial groove 3 of the male shaft 1 on the side larger than the ball pitch circle 10 diameter and the axial groove 5 of the female shaft 2 opposed to the groove 3 The spherical body 7 is constrained in the circumferential direction by the inner edge portion 5b on the side of the portion smaller than 10 diameters. By this operation, in the present embodiment, the rigidity in the rotational direction between the male shaft 1 and the female shaft 2 can be improved in the same manner as or more than the first embodiment in FIG. The torque can be transmitted in the state.
[0036]
In the first and second embodiments, a plurality of pairs of axial grooves 3 and 5 formed on the outer peripheral surface of the male shaft 1 and the inner peripheral surface of the female shaft 2 are formed in six rows. Other configurations are possible as long as the number of rows is equal to or greater than the number of rows and the number of rows is even.
[0037]
Further, in the first and second embodiments, the arrangement angle patterns of the axial grooves 3 adjacent to the male shaft 1 are different, small → large → small → large → small → large. Although the arrangement angle pattern of the direction grooves 5 is the same at 60 ° for all six, the arrangement angle pattern of the adjacent axial grooves 3 of the male shaft 1 is not limited to this configuration, but is also small → large → small → large ... However, the arrangement angle of the axial groove 5 adjacent to the female shaft 2 corresponding to each arrangement angle is large → small → large → small → large → small, that is, adjacent to the male shaft 1. The arrangement angle of the adjacent axial grooves 5 of the female shaft 2 that opposes the small (or large) arrangement angle of the corresponding axial groove 3 can be made large (or small).
[0038]
In this case, the arrangement angle of the adjacent axial groove 3 of the female shaft 2 is small, and the arrangement angle of the adjacent axial groove 3 of the male shaft 1 is large at the portion where the inner diameter between them is larger than the ball pitch circle diameter 10. The portion b in which the outside diameter is larger than the ball pitch circle diameter 10 is opposed. The arrangement angle of the adjacent axial grooves 3 of the female shaft 2 is large, and the arrangement angle of the adjacent axial grooves 3 of the male shaft 1 is small in the portion a where the inner diameter between them is smaller than the ball pitch circle diameter 10. Thus, a portion in which the outer diameter is smaller than the ball pitch circle diameter 10 faces each other.
[0039]
As a result, the spherical body 7 can be more securely restrained in the circumferential direction, so that rattling in the rotational direction between the male shaft 1 and the female shaft 2 is prevented, and torque is transmitted in a highly rigid state. It is effective.
[0040]
【The invention's effect】
As described above, according to the present invention, the function of restricting the torque transmitting member in the circumferential direction is more effectively exhibited, and the rigidity of the male shaft and the female shaft in the rotational direction can be improved.
[0041]
Therefore, torque can be transmitted in a state of high rigidity, a stable sliding load can be realized, and rattling in the shaft rotation direction can be reliably prevented. Moreover, it has excellent durability and can be realized at low cost.
In addition, since the preload can be applied in the shaft rotation direction only by the male shaft, the female shaft, and the torque transmitting member, a means for applying a preload such as an elastic body can be omitted.
[Brief description of the drawings]
FIG. 1 is a radial cross-sectional view of a telescopic shaft for vehicle steering according to a first embodiment of the present invention.
FIG. 2 is a longitudinal sectional view showing a telescopic shaft for vehicle steering in FIG.
FIG. 3 is a radial sectional view showing the female shaft of FIG. 1;
FIG. 4 is a radial sectional view showing the male shaft of FIG. 1;
FIG. 5 is a side view of a steering mechanism of an automobile to which the telescopic shaft for vehicle steering according to the embodiment of the present invention is applied.
FIG. 6 is a radial sectional view of a vehicle steering telescopic shaft according to a second embodiment of the present invention.
FIG. 7 is a radial sectional view showing the female shaft of FIG. 6;
FIG. 8 is a radial sectional view showing the male shaft of FIG. 6;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Male shaft 2 Female shaft 3 Male shaft axial groove 5 Female shaft axial groove 7 Torque transmitting member (spherical body)
Reference Signs List 10 Ball pitch circle 11 Stop ring 100 Body side member 101 Upper bracket 102 Lower bracket 103 Steering column 104 Steering shaft 105 Steering wheel 106 Universal joint 107 Lower steering shaft part 108 Steering shaft joint 109 Pinion shaft 110 Frame 111 Elastic body 112 Steering rack shaft 113 Steering rack support member 120 Upper steering shaft

Claims (2)

In a telescopic shaft for steering of a vehicle, in which a male shaft and a female shaft are fitted to each other so as to be non-rotatably and slidably, incorporated into a steering shaft of the vehicle,
Between a plurality of pairs of axial grooves formed on the outer peripheral surface of the male shaft and the inner peripheral surface of the female shaft, a torque transmitting member that rolls when the two shafts move relative to each other in the axial direction is arranged.
The outer diameter of the outer peripheral surface of the male shaft is larger than a ball pitch circle diameter passing through the rolling center of the torque transmitting member and smaller than the ball pitch circle diameter, and are alternately formed with the axial groove interposed therebetween. The inner diameter of the inner peripheral surface of the female shaft is larger or smaller than the ball pitch circle diameter according to the outer diameter of the male shaft. A steering telescopic shaft for a vehicle, wherein the telescopic shaft is formed alternately with a direction groove interposed therebetween. 2. The vehicle according to claim 1, wherein the plurality of pairs of axial grooves formed on the outer peripheral surface of the male shaft and the inner peripheral surface of the female shaft are four or more rows and are even rows. 3. Telescopic shaft for steering.

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