JPH05170108A - Joint for steering shaft - Google Patents

Abstract

PURPOSE:To improve the responsiveness at the time of steering by efficiently damping the vibration from the front wheel side with a vibration control rubber. CONSTITUTION:A spring member 12 having a plate spring section 14 is fixed to a first shaft 7. A flat face 15 to be pressure-contacted with the plate spring section 14 is formed on a second shaft 9. The rotational torque is transferred from the first shaft 7 to the second shaft 9 via the spring member 12 before a vibration control rubber 8 reaches the elastic limit. The vibration transferred to the second shaft 9 is mainly transferred to the vibration control rubber 8 because the plate spring section 14 is merely kept in contact with the second shaft 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering shaft joint mounted between a steering shaft and a steering gear unit of an automobile.

[0002]

2. Description of the Related Art Conventionally, steering devices for automobiles are
In some cases, a rubber vibration isolator is provided in the torque transmission path in order to prevent traveling vibration or the like from being transmitted from the front wheel side to the steering wheel side during traveling. A conventional steering device of this type will be described with reference to FIGS.

FIG. 6 is a perspective view showing a steering shaft portion of a conventional steering device, FIG. 7 is a cross-sectional view of an intermediate shaft, and FIG. 8 is VIII-VIII in FIG.
It is a line sectional view.

In these figures, 1 is a steering wheel of an automobile and 2 is a steering shaft. The steering shaft 2 is rotatably supported by a vehicle body (not shown), and the steering wheel 1 is attached to one end thereof.

Reference numeral 3 denotes a steering gear unit serving as a main body of the power steering apparatus. The steering gear unit 3 is constructed such that a front wheel (not shown) is steered left and right by rotating an input shaft 3a.

The steering shaft 2 is connected to the input shaft 3a of the steering gear unit 3 via an intermediate shaft 6 having universal joints 4 and 5 connected at both ends.

The intermediate shaft 6 is
As shown in FIG. 7, it is composed of a cylindrical first shaft 7 and a second shaft 9 which is inserted and coupled to the hollow portion of the first shaft 7 via a vibration-proof rubber 8. The first shaft 7 is connected to the steering shaft 2 via the universal joint 4, and the second shaft 9
Is spline-coupled to the universal joint 5 and connected to the input shaft 3 a of the steering gear unit 3 via the universal joint 5.

Further, flat portions 7a, 7a which are parallel to each other are formed on the first shaft 7, and the anti-vibration rubber 8 and the second shaft 9 have flat portions corresponding to the flat portions 7a. There is. This flat portion acts as a detent for the shaft connecting portion, and the rotational torque is transmitted from the first shaft 7 to the second shaft 9.

A concave groove 9a for holding the vibration-proof rubber 8 is formed on the second shaft 9.

When the intermediate shaft 6 is interposed between the steering shaft 2 and the steering gear unit 3 as described above, steering is performed from the steering shaft 2 side through the universal joint 4, the intermediate shaft 6 and the universal joint 5 during steering. Rotational torque is transmitted to the input shaft 3a of the gear unit 3.

When the intermediate shaft 6 rotates, first, the first shaft 7 slightly rotates so as to bend the antivibration rubber 8. Since the rotational torque transmitted to the second shaft is small when the anti-vibration rubber 8 is elastically deformed, at that time, the angle change amount of the front wheel with respect to the rotation amount of the steering wheel 1 is relatively small.

After the amount of deformation of the vibration isolating rubber 8 increases and reaches the elastic limit, the second shaft 9 rotates together with the first shaft 7 due to the action of the flat portion described above. At this time, the amount of change in the angle of the front wheels with respect to the amount of rotation of the steering wheel 1 becomes larger than that during the elastic deformation described above.

The vibrations and sounds transmitted from the steering gear unit 3 to the steering wheel 1 side during traveling are
The anti-vibration rubber 8 of the intermediate shaft 6 attenuates the vibration.

[0014]

However, when the anti-vibration rubber 8 is interposed in the torque transmission path as described above, the anti-vibration rubber 8 does not change relative to the rotation amount of the steering wheel 1 until the anti-vibration rubber 8 is elastically deformed by a certain amount. Since the amount of change in the angle of the front wheels is relatively small, the responsiveness of the front wheels at the beginning of steering is low.

In order to solve such a problem, the hardness of the vibration isolating rubber 8 may be increased. However, in such a case, it becomes impossible to block vibrations and sounds from the steering gear unit 3 side.

[0016]

A steering shaft joint according to the present invention is provided with a spring member, one end of which is extended toward the other shaft member, on one of the shaft members.
The other shaft member is provided with an engaging portion with which the tip end portion of the spring member engages at least when not in a straight traveling state.

[0017]

The rotating torque is transmitted from one shaft member to the other shaft member through the spring member before the vibration-proof rubber reaches the elastic limit. The vibrations and sounds transmitted from the steering gear unit side are in a state of contacting each other when the spring member is engaged with the engaging portion, and thus are difficult to be transmitted to the spring member and are mainly transmitted to the vibration-proof rubber. Reportedly.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to FIGS. 1 is a plan view showing a main portion of a steering shaft joint according to the present invention, FIG. 2 is a vertical cross-sectional view of the steering shaft joint according to the present invention, and a broken portion shown in FIG. 1 is a II-II line in FIG. A cross section is shown. FIG. 3 is a sectional view taken along the line III-III in FIG. 2, and FIG. 4 is a graph showing a transmission torque characteristic of the steering joint according to the present invention. In these figures, the same or equivalent members as those described in FIGS. 6 to 8 are designated by the same reference numerals, and detailed description thereof will be omitted.

In these figures, 11 is an intermediate shaft as a steering shaft joint according to the present invention. The intermediate shaft 11 is inserted and coupled to a first shaft 7 connected to a steering shaft (not shown) via a universal joint 4 and a hollow portion of the first shaft 7 via a vibration-proof rubber 8. It is composed of a second shaft 9 and a spring member 12 welded to the axial end portion of the first shaft 7.

The spring member 12 is entirely formed of a spring material, and has an annular portion 13 fitted to the outer peripheral portion of the first shaft 7 and welded, and the intermediate shaft 11 from the annular portion 13. It is formed of two leaf spring portions 14, 14 extending toward the second shaft 9 side along the axial direction of.

The leaf spring portions 14 are formed at positions corresponding to the two planes 15, 15 formed on the second shaft 9, respectively. The tip of the leaf spring portion 14 is curved toward the axial center of the second shaft 9, and the top of the curved portion is in pressure contact with the flat surfaces 15 and 15.
In the present embodiment, even when the steering shaft is positioned at a position where the vehicle body is in a straight traveling state, the apex of the top surface is 15
It is formed so as to be pressed against.

That is, the spring member 12 is engaged with the second shaft 9 by the two plate spring portions 14 pressing the second shaft 9 in the radial direction. The engaging portion of the second shaft 9 is the flat surface 15 in this embodiment.

When the intermediate shaft 11 thus constructed is mounted on the steering device, the rotational torque transmitted from the steering shaft during steering is first transmitted to the first shaft 7.

When the first shaft 7 rotates, the vibration isolating rubber 8 is elastically deformed in the initial stage of rotation because the load of the steering gear unit is applied to the second shaft 9. At this time, the second shaft 9 is
The torque transmitted to is small. On the other hand, when the first shaft 7 rotates, the spring member 12 provided at the shaft end portion also rotates at the same time, so that torque is transmitted to the second shaft 9 via the spring member 12. Since the leaf spring portion 14 of the spring member 12 also bends, all the rotational torque applied to the first shaft 7 is not transmitted to the second shaft 9.

That is, in the initial stage of rotation of the first shaft 7, a rotational torque that is a composite of a slight torque transmitted via the vibration isolating rubber 8 and a relatively large torque transmitted via the spring member 12 is the second shaft. 9 will be transmitted.

When the steering wheel is further turned to perform the steering operation, the elastic deformation amount of the vibration isolating rubber 8 gradually increases, and eventually the vibration isolating rubber 8 reaches the elastic limit. Then, the flat portion 7 of the first shaft 7
a presses the flat surface 15 of the second shaft 9 via the anti-vibration rubber 8, and the first shaft 7 and the second shaft 9
And will rotate together. At that time as well, the rotational torque is transmitted via the spring member 12.

The amount of change in the angle of the front wheel with respect to the amount of rotation of the steering wheel 1 at this time is larger than that during the elastic deformation of the anti-vibration rubber 8.

FIG. 4 shows the relationship between the transmission torque transmitted to the second shaft 9 and the torsion angle of the second shaft 9. The solid line in FIG. 4 indicates the intermediate shaft 11 according to the present invention.
Is used, and the broken line shows the case where a conventional one is used. Further, θ ₁ and θ ₂ respectively indicate twist angles when the vibration-proof rubber 8 reaches the elastic limit.

As shown in the figure, the increase amount of the transmission torque with respect to the increase amount of the torsion angle is larger in the intermediate shaft 11 of the present invention than in the conventional one until the vibration isolating rubber 8 reaches the elastic limit. You can see that it is increasing.

The vibrations and sounds transmitted from the steering gear unit 3 to the steering wheel 1 side during traveling are
It is transmitted from the universal joint 5 to the second shaft 9 of the intermediate shaft 11.

When the second shaft 9 vibrates, the spring member 1
Since the second spring portion 14 is only in contact with the second shaft 9, its vibration is difficult to be transmitted to the spring member 12, and is mainly transmitted to the vibration isolating rubber 8. That is, the vibrations and sounds transmitted from the steering gear unit side are attenuated by the anti-vibration rubber 8 as is conventionally done.

Therefore, in the intermediate shaft 11 according to the present invention, even if the vibration isolating rubber 8 does not reach the elastic limit, the rotational torque of the intermediate shaft 11 is set to the first value via the spring member 12.
The shaft 7 can be transmitted to the second shaft 9.

The initial torque can be changed by changing the spring constant of the spring member 12. That is, if the spring constant is set large, the response becomes high, and conversely, if the spring constant is set small, the response becomes poor.
The degree of freedom in design will increase.

Although the spring member 12 is welded to the first shaft 7 in this embodiment, the spring member 12 may be fixed by screw fixing, press fitting, or the like. You can also FIG. 5 shows a spring member in the case of screwing.

FIG. 5 is a view showing another embodiment of the spring member,
The figure (a) is a plan view, the figure (b) is a left side view, the figure (c) is a front view, and the figure (d) is a right side view. In these figures, the same or equivalent members as those described in FIGS. 1 to 3 are designated by the same reference numerals, and detailed description thereof will be omitted. The spring member 12 shown in FIG.
3 is formed by bending a plate material, a nut 13a is fixed to one end thereof, and a fastening bolt insertion hole 13b is formed at the other end thereof.

That is, the ring portion 13 is structured to be fastened to the first shaft, for example. Even with this structure, the same effect as that of the above embodiment can be obtained.

Further, when the screw fixing type is adopted, as shown in FIG.
The structure shown in Fig. 5 is divided into two halves, and both members are connected by bolts so that the first shaft is sandwiched. It is also possible to provide a structure in which the annular portion can be opened and closed. According to this structure, the spring member can be attached after the second shaft is coupled to the first shaft (the intermediate shaft may be interposed in the steering system), which facilitates the assembly. ..

In each of the above embodiments, the leaf spring portion is pressed against the second shaft even when the vehicle body is in the straight traveling state (when the steering shaft is not rotating). It is also possible to simply bring the leaf spring portion into contact with the second shaft without applying pressure to the second shaft in a state in which is not rotated.

Further, the leaf spring portion and the second shaft are formed so that a minute gap is generated between the leaf spring portion and the second shaft when the steering shaft is not rotated (when the vehicle body is in a straight traveling state). You can also

The dimension of the minute gap in such a configuration is set to a value such that the leaf spring portion contacts the second shaft before the vibration-proof rubber reaches the elastic limit. When the minute gap is provided between the leaf spring portion and the second shaft as described above, the leaf spring can be used when the vehicle body is in a straight traveling state or when the steering shaft is slightly operated to rotate the first shaft together with the steering shaft. The vibration transmitted from the steering gear unit can all be transmitted to the anti-vibration rubber until the portion contacts the second shaft.

Furthermore, in each of the above-mentioned examples, the first spring member is used.
Although the example of fixing to the shaft is shown, the present invention can be fixed to the second shaft without being limited to such a limitation.

Further, in addition to the structure in which the leaf spring is brought into contact with the flat surface of the second shaft, the leaf spring may be engaged with the receiving member protruding from the second shaft.

In addition to the leaf spring type spring member, a coil spring may be used.

[0044]

As described above, the steering shaft joint according to the first invention has one of the shaft members,
Since the tip end portion is provided with a spring member extending toward the other shaft member side, and the other shaft member is provided with an engagement portion with which the tip end portion of the spring member engages at least when not in a straight traveling state, vibration isolation Before the rubber reaches the elastic limit, the rotational torque is transmitted from one shaft member to the other shaft member via the spring member. Therefore, even if the rotation amount of one shaft member is small, the other shaft member rotates.

Since the vibration and sound transmitted from the steering gear unit side are in a state of contacting each other when the spring member is engaged with the engaging portion, they are difficult to be transmitted to the spring member and are mainly prevented. It is passed on to the rubber band.

Therefore, it is possible to enhance the responsiveness of the front wheels at the initial stage of steering, while using the anti-vibration rubber that easily attenuates the vibration and sound transmitted from the steering gear unit side.

Further, the present invention can be easily implemented because only the spring member is added to the conventional joint.

[Brief description of drawings]

FIG. 1 is a plan view showing a main part of a steering shaft joint according to the present invention.

FIG. 2 is a longitudinal sectional view of a steering shaft joint according to the present invention.

3 is a sectional view taken along line III-III in FIG.

FIG. 4 is a graph showing a transmission torque characteristic of a steering joint according to the present invention.

5A and 5B are views showing another embodiment of the spring member, wherein FIG. 5A is a plan view, FIG. 5B is a left side view, FIG. 5C is a front view, and FIG. Is a right side view.

FIG. 6 is a perspective view showing a steering shaft portion of a conventional steering device.

FIG. 7 is a cross-sectional view of an intermediate shaft.

8 is a sectional view taken along line VIII-VIII in FIG.

[Explanation of symbols]

 4 Universal Joint 5 Universal Joint 7 First Shaft 8 Anti-vibration Rubber 9 Second Shaft 11 Intermediate Shaft 12 Spring Member 14 Leaf Spring 15 Flat Surface

Claims (1)

[Claims] 1. A steering shaft joint, which is formed by connecting shaft members to each other via a vibration-proof rubber, and is interposed between a steering shaft and a steering gear unit. Is provided with a spring member extending to the other shaft member side, and at least the other shaft member is provided with an engaging portion with which the tip end portion of the spring member engages at least when not in a straight traveling state. Steering shaft joint.