JP2003306152A - Intermediate shaft for vehicle steering - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an intermediate shaft for a vehicle steering having a two-stage rigidity characteristic of low rigidity and high rigidity in which a change from the low rigidity to the high rigidity is made smooth, while effectively utilizing a space. <P>SOLUTION: After rattling to some extent is formed on spline fitting parts 3, 4 of both shafts 1, 2, the spline fitting part 3 of the male shaft 1 is stretched in the spline fitting part 4 of the female shaft 2 by inserting the spline fitting part 3 of the male shaft 1 having a cross-like slit 5 and opening the slit 5. Thereby, a position of the slit 5 of the spline fitting parts 3, 4 of both shafts 1, 2 can be made to the low rigid part provided with low rigidity characteristic that a steering torque transmitted is lowered corresponding to a displacement amount of a relative angle of the male shaft 1 and the female shaft 2 of the intermediate shaft near a neutral position where a transmitted torque of the intermediate shaft is approximate zero. The rigidity of the low rigid part can be adjusted by adjusting the opening of the slit 5. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intermediate shaft for vehicle steering used in an automobile, and more particularly, a spline fitting portion of a male shaft is coated with a synthetic resin cushioning body and is mounted on a vehicle. The present invention relates to an intermediate shaft for vehicle steering having two-stage rigidity characteristics of low rigidity and high rigidity while effectively utilizing the above space.

[0002]

2. Description of the Related Art In a vehicle steering system, an intermediate shaft is provided, for example, between a universal joint provided on the steering shaft side and a universal joint provided on the steering gear side. The intermediate shaft is composed of a male shaft and a female shaft that are non-rotatably and slidably fitted to each other and are spline-fitted, and prevent the rattling so as to reliably transmit the steering torque of the driver to the steering gear. While the steering torque can be transmitted in a rigid state, it absorbs axial displacement that occurs when the vehicle is running, and it can expand and contract during disassembly and assembly, so it slides in the axial direction with a relatively low and stable sliding load. You can do it.

The intermediate shaft prevents metallic noise and metallic hammering noise, suppresses transmission of vibration from the engine and road surface to the steering wheel, and does not give a rattling steering feeling. In order to ensure reliable sliding at all times, for example, Japanese Patent Laid-Open No. 2000-74081
As disclosed in the publication, there is a male shaft spline fitting portion coated with a synthetic resin buffer.

In the case of an intermediate shaft coated with a synthetic resin, the relationship between the steering torque transmitted and the displacement becomes a diagram as shown in FIG. 2 when there is no rattling steering feeling, and there is a substantially proportional relationship. And draw a slight hysteresis loop.

On the other hand, when a rattling steering feeling is produced, the diagram is as shown in FIG. 3, and in the vicinity of the neutral position (transmission torque 0) of the intermediate shaft, the steering torque is irrespective of the rotation of the steering wheel. Is almost never generated.

As shown in FIG. 1, the relationship between the steering torque to be transmitted and the displacement is such that during normal steering, the steering torque is surely transmitted with a relatively high rigidity, while the intermediate position of the intermediate shaft (transmission) is transmitted. In the vicinity of the torque 0), a "low rigidity portion" is provided to reduce the steering torque transmitted with respect to the rotation amount (displacement) of the steering wheel.
There is a desire to have two-stage rigidity characteristics.

[0007]

However, in order to realize such a two-stage rigidity characteristic, Japanese Patent Laid-Open No. 8-
As in the elastic shaft coupling disclosed in Japanese Patent No. 133097, a cushioning body such as a rubber elastic body is provided between the yoke of the universal joint and the intermediate shaft, whereby the cushioning body is interposed during steering with low torque. While the steering torque is transmitted in the low rigidity state, it is necessary to transmit the steering torque in the high rigidity state through a portion other than the shock absorber during steering with high torque.

Since it is necessary to provide such a shock absorber on the yoke of the universal joint, the space for effective use on the vehicle is reduced by the amount of the shock absorber, and the space is reduced in spite of the relatively narrow space. There are cases where effective use cannot be achieved.

Further, in the conventional elastic shaft coupling, as shown in FIG. 1, since the change from the low rigidity to the high rigidity is abrupt, the change from the low rigidity to the high rigidity is not smoothly performed, and the steering feeling is not increased. Is sometimes bad.

Further, the cushioning body made of rubber or the like has a relatively large hysteresis loop as a rigidity characteristic, so that it may not be possible to obtain a desired two-stage rigidity characteristic.

The present invention has been made in view of the above-mentioned circumstances, and has a two-stage rigidity characteristic of low rigidity and high rigidity while effectively utilizing the space on the vehicle. An object of the present invention is to provide an intermediate shaft for vehicle steering, in which a change in rigidity characteristic from low rigidity to high rigidity is smooth.

[0012]

In order to achieve the above object, an intermediate shaft for vehicle steering according to the present invention is incorporated in a steering shaft of a vehicle, and a male shaft and a female shaft are non-rotatable and slidable. In an intermediate shaft for vehicle steering, near the neutral position where the transmission torque of the intermediate shaft is substantially 0, the steering torque transmitted according to the relative angular displacement amount of the male shaft and the female shaft of the intermediate shaft is reduced to be low. It has rigidity characteristics.

Further, in the intermediate shaft for vehicle steering according to the present invention, the fitting portion of the male shaft is coated with a shock absorbing member made of synthetic resin, and the both shafts can always slide.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION An intermediate shaft for vehicle steering according to an embodiment of the present invention will be described below with reference to the drawings.

(Overall Configuration of Embodiment) FIG. 4A shows
FIG. 4 is a vertical cross-sectional view of the intermediate shaft for vehicle steering according to the embodiment of the present invention, and FIG. 4B is a graph showing the relationship between the transmission torque and the displacement of the intermediate shaft according to the present invention.

A male shaft 1 and a female shaft 2 are provided between the universal joint on the steering shaft side and the universal joint on the steering gear side.
An intermediate shaft consisting of and is provided. Male shaft 1 and female shaft 2
Have spline fitting portions 3 and 4 which are non-rotatably and slidably fitted to each other.

The spline fitting portion 3 of the male shaft 1 is coated with a buffer made of synthetic resin. Here, as a concrete material of the buffer made of synthetic resin, nylon coating or PTFE (poly-tetrafluoru-ethylene:
For example, a coating of (tetrafluoroethylene) or a coating of a thin film containing molybdenum dioxide is used. This prevents metal noise and metal tapping noise, suppresses the transmission of vibrations from the engine and road surface to the steering wheel, does not give a rattling steering feeling, and ensures a constant sliding. I can do it.

As described above, according to the present invention, the intermediate shaft is provided with the male shaft 1 of the intermediate shaft in the vicinity of the neutral position where the transmission torque of the intermediate shaft is substantially 0 as shown in FIG. 4B. A low-rigidity portion having low-rigidity characteristics that reduces the steering torque transmitted according to the relative angular displacement of the female shaft 2 is provided. Since the intermediate shaft according to the present invention has a rigidity characteristic in which the change from low rigidity to high rigidity is gradual, the change in the rigidity characteristic from low rigidity to high rigidity is performed smoothly and there is little discomfort. It is configured so that a steering feeling can be obtained.

Therefore, while effectively utilizing the space on the vehicle, the vehicle steering system has the two-stage rigidity characteristics of low rigidity and high rigidity, and the change of the rigidity characteristics from low rigidity to high rigidity is smooth. Intermediate shaft can be realized.

Further, the spline fitting portion 3 of the male shaft 1 is coated with a synthetic resin cushioning member, which realizes two-stage rigidity characteristics of low rigidity and high rigidity, while both shafts are constantly slid. Can move.

(First Embodiment) FIG. 5 (a) is a front view of a male shaft of a vehicle steering intermediate shaft according to a first embodiment of the present invention, and FIG. 5 (b) is a side view thereof. Yes, (c) is a partial perspective view of the low rigidity portion.

In this embodiment, a cross-shaped slit 5 is formed in the spline fitting portion 3 of the male shaft 1 coated with resin.

In the spline fitting parts 3 and 4 of both shafts 1 and 2,
After forming a certain amount of backlash, cross-shaped slit 5
Insert the spline fitting part 3 of the male shaft 1 having
As shown in (c), by opening the slit 5, the spline fitting portion 3 of the male shaft 1 is stretched into the spline fitting portion 4 of the female shaft 2.

As a result, the positions of the slits 5 of the spline fitting portions 3 and 4 of the two shafts 1 and 2 are close to the neutral position where the transmission torque of the intermediate shaft is substantially 0, and the male shaft 1 and the female shaft of the intermediate shaft are close to each other. It is possible to provide a low-rigidity portion having low-rigidity characteristics in which the steering torque transmitted according to the relative angular displacement amount of 2 is reduced.

By adjusting the opening degree of the slit 5, the rigidity of the low rigidity portion can be adjusted.

A circular hole 6 is formed at the base of the slit 5 in order to facilitate the adjustment of the low rigidity portion.

Further, in the spline fitting portions 3 and 4 of the two shafts 1 and 2, the slit 5 has a portion other than the low rigidity portion.
High rigidity characteristics can be exhibited.

Therefore, while effectively utilizing the space on the vehicle, the vehicle steering system has two-stage rigidity characteristics of low rigidity and high rigidity, and the change in rigidity characteristics from low rigidity to high rigidity is smooth. Intermediate shaft can be realized.

(Second Embodiment) FIG. 6A is a front view of a male shaft of an intermediate shaft for vehicle steering according to a second embodiment of the present invention, and FIG. 6B is a side view thereof. is there.

In the present embodiment, in the spline fitting portion 3 of the male shaft 1, the boring 7 is formed at the low rigidity portion of the slit 5. By providing the boring 7, it is possible to further adjust the low rigidity portion. Other configurations are similar to those of the above-described embodiment.

(Third Embodiment) FIG. 7A is a front view of a male shaft of a vehicle steering intermediate shaft according to a third embodiment of the present invention, and FIG. 7B is a side view thereof. Yes, (c) is a partial perspective view of the low rigidity portion.

In the present embodiment, a linear slit 8 is provided instead of the cross slit 5. Both shafts 1, 2
After forming a certain amount of backlash in the spline fitting portions 3 and 4, the spline fitting portion 3 of the male shaft 1 having the slit 8 of a single character is inserted, and as shown in FIG. By opening the one-letter slit 8 in two directions, the spline fitting portion 3 of the male shaft 1 is stretched into the spline fitting portion 4 of the female shaft 2. As a result, the slits 8 of the spline fitting portions 3 and 4 of the two shafts 1 and 2 are relatively positioned between the male shaft 1 and the female shaft 2 of the intermediate shaft near the neutral position where the transmission torque of the intermediate shaft is substantially zero. A low-rigidity portion having low-rigidity characteristics in which the steering torque transmitted according to the amount of angular displacement is reduced can be provided. The rigidity of the low-rigidity portion can be adjusted by adjusting the opening degree of the slit 8. Other configurations are similar to those of the above-described embodiment.

(Fourth Embodiment) FIG. 8 (a) is a front view of a male shaft of a vehicle steering intermediate shaft according to a fourth embodiment of the present invention, and FIG. 8 (b) is a side view thereof. is there.

In the present embodiment, in the spline fitting portion 3 of the male shaft 1 of the third embodiment, a boring 7 is formed at the low rigidity portion of the slit 8. By providing the boring 7, it is possible to further adjust the low rigidity portion. Other configurations are similar to those of the above-described embodiment.

(Fifth Embodiment) FIG. 9A is a front view of a male shaft of an intermediate shaft for vehicle steering according to a fifth embodiment of the present invention, and FIG. It is a perspective view and (c) is a side view of a male shaft.

In this embodiment, the notch 9 is formed in the spline fitting portion 3 of the male shaft 1 coated with resin,
An elastic body 10 such as rubber and a top member 11 are provided in the notch 9.
I am wearing. Splines are formed on the outer peripheral surface of the top member 11.

In the spline fitting portions 3 and 4 of both shafts 1 and 2,
After forming a certain amount of play, the spline fitting portion 3 of the male shaft 1 having the elastic body 10 and the top member 11 is inserted.

An inner peripheral surface of the spline fitting portion 4 of the female shaft 2,
Make sure that the outer peripheral surface of the top member 11 is closely fitted,
The thickness of the elastic body 10 is adjusted.

As a result, the spline fitting portions 3 and 4 of the shafts 1 and 2 are provided with the top member 11 near the neutral position where the transmission torque of the intermediate shaft is approximately 0 and the male shaft 1 and the female shaft of the intermediate shaft. A low-rigidity portion having a low-rigidity characteristic in which the steering torque transmitted according to the relative angular displacement of the shaft 2 is reduced can be provided.

The rigidity of the low-rigidity portion can be adjusted by adjusting the rigidity of the elastic body 10.

Further, in the spline fitting portions 3 and 4 of the two shafts 1 and 2, portions other than the low rigidity portion of the top member 11 can exhibit high rigidity characteristics.

Therefore, while effectively utilizing the space on the vehicle, the vehicle steering having the two-stage rigidity characteristics of low rigidity and high rigidity, and the change of the rigidity characteristics from low rigidity to high rigidity is smooth. Intermediate shaft can be realized.

(Sixth Embodiment) FIG. 10A is a vertical sectional view of a female shaft of an intermediate shaft for vehicle steering according to a sixth embodiment of the present invention, and FIG. 10B is a front view thereof. Is.

In the present embodiment, the spline fitting portion 4 of the female shaft 2 has a cross-shaped slit 12 formed therein.

In the spline fitting portions 3 and 4 of both shafts 1 and 2,
After forming a certain amount of play, cross-shaped slit 1
By fitting the spline fitting portion 4 of the female shaft 2 having 2 and closing the slit 12, the spline fitting portion 4 of the female shaft 2 is pressed against the spline fitting portion 3 of the male shaft 1.

As a result, the positions of the slits 12 of the spline fitting portions 3 and 4 of the two shafts 1 and 2 are close to the neutral position where the transmission torque of the intermediate shaft is approximately 0, and the male shaft 1 and the female shaft of the intermediate shaft are close to each other. It is possible to provide a low-rigidity portion having low-rigidity characteristics in which the steering torque transmitted according to the relative angular displacement amount of 2 is reduced.

The rigidity of the low rigidity portion can be adjusted by adjusting the closing degree of the slit 12.

A circular hole 13 is formed at the base of the slit 12 to facilitate adjustment of the low-rigidity portion.

Further, in the spline fitting portions 3 and 4 of both the shafts 1 and 2, portions other than the low rigidity portion of the slit 12 can exhibit high rigidity characteristics.

Therefore, while effectively utilizing the space on the vehicle, the vehicle steering system has a two-stage rigidity characteristic of low rigidity and high rigidity, and has a smooth change in rigidity characteristic from low rigidity to high rigidity. Intermediate shaft can be realized.

In the above embodiment, the case where the buffer body made of synthetic resin is coated is shown, but the case where the buffer body is not coated can be applied.

The present invention is not limited to the above-described embodiment, but can be modified in various ways.

[0053]

As described above, according to the present invention,
The intermediate shaft has a low rigidity characteristic in which a steering torque transmitted according to the relative angular displacement amount of the male shaft and the female shaft of the intermediate shaft is reduced in the vicinity of the neutral position where the transmission torque of the intermediate shaft is substantially zero. Since a rigid part is provided,
Realizes an intermediate shaft for vehicle steering that has two-stage rigidity characteristics of low rigidity and high rigidity, and that changes in rigidity characteristics smoothly from low rigidity to high rigidity while making effective use of the space on the vehicle. can do.

Further, the fitting portion of the male shaft is coated with a buffer member made of synthetic resin so that both shafts can slide at all times.

Therefore, both shafts can always slide while realizing two-stage rigidity characteristics of low rigidity and high rigidity.

[Brief description of drawings]

FIG. 1 is a graph showing a relationship between transmission torque and displacement according to an example of an elastic shaft coupling.

FIG. 2 is a graph showing the relationship between transmission torque and displacement according to another example.

FIG. 3 is a graph showing the relationship between transmission torque and displacement according to another example.

FIG. 4A is a longitudinal sectional view of an intermediate shaft for vehicle steering according to an embodiment of the present invention, and FIG.
FIG. 4 is a diagram showing a relationship between a transmission torque and displacement according to the present invention.

FIG. 5A is a front view of the male shaft of the intermediate shaft for vehicle steering according to the first embodiment of the present invention,
(B) is a side view thereof, and (c) is a partial perspective view of the low-rigidity portion.

FIG. 6 (a) is a front view of a male shaft of an intermediate shaft for vehicle steering according to a second embodiment of the present invention,
(B) is the side view.

FIG. 7 (a) is a front view of a male shaft of an intermediate shaft for vehicle steering according to a third embodiment of the present invention,
(B) is a side view thereof, and (c) is a partial perspective view of the low-rigidity portion.

FIG. 8A is a front view of a male shaft of an intermediate shaft for vehicle steering according to a fourth embodiment of the present invention,
(B) is the side view.

FIG. 9 (a) is a front view of a male shaft of an intermediate shaft for vehicle steering according to a fifth embodiment of the present invention,
(B) is a perspective view of a low-rigidity part, and (c) is a side view of a male shaft.

FIG. 10 (a) is a vertical cross-sectional view of a female shaft of an intermediate shaft for vehicle steering according to a sixth embodiment of the present invention, and FIG. 10 (b) is a front view thereof.

[Explanation of symbols]

1 male axis 2 female shaft 3 Spline fitting part (male shaft) 4 Spline fitting part (female shaft) 5 slits 6 circular holes 7 boring 8 slits 9 Notch 10 Elastic body 11 Top member 12 slits 13 circular hole

Claims (2)

[Claims] 1. A steering shaft of a vehicle,
In an intermediate shaft for vehicle steering in which a male shaft and a female shaft are non-rotatably and slidably configured, in the vicinity of a neutral position where the transmission torque of the intermediate shaft is substantially 0, the male shaft and the female shaft of the intermediate shaft are An intermediate shaft for vehicle steering, which has a low rigidity characteristic in which a steering torque transmitted according to a relative angular displacement amount is reduced. 2. The intermediate shaft for vehicle steering according to claim 1, wherein the fitting portion of the male shaft is coated with a shock-absorbing body made of synthetic resin, and the both shafts can always slide.