JP3758018B2 - Steering gear box fixing device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fixing device for attaching a steering gear box to a vehicle or the like.
[0002]
[Prior art]
In a vehicle or the like, a steering device is provided to transmit a steering force input to a steering wheel to a steering wheel. FIG. 4 is a front view of a steering device according to the prior art.
[0003]
In FIG. 4, a rack shaft (not shown) extends horizontally in a cylindrical steering gear box 10, and both ends thereof are connected to tie rods 11 and 12. The ends of the tie rods 11 and 12 are connected to a steering device (not shown). In the steering gear box 10, the pinion shaft 13 and the rack shaft are engaged with each other, and the upper end of the pinion shaft 13 protruding upward from the steering gear box 10 is the lower end of a steering shaft (not shown) extending from above. It is connected to.
[0004]
When a person who drives the vehicle rotates a steering wheel (not shown), the pinion shaft 13 rotates and the rack shaft moves to the left and right accordingly. Therefore, the tie rods 11 and 12 that move together with the rack shaft cause the pinion shaft 13 to move. A steering angle is given to the steered wheels via the steering mechanism.
[0005]
By the way, the steering gear box 10 receives a so-called steering reaction force transmitted from the wheel at the time of steering, and is often attached to the vehicle body via a fixing device having an elastic portion to absorb this. A conventional example of such a fixing device will be described below.
[0006]
FIG. 5 is an enlarged cross-sectional view of the steering gear box 10 of FIG. 4 taken along the line VV and viewed in the direction of the arrow. A bush body 14 is inserted into each mounting hole 10a. The bush body 14 includes an iron cylindrical sleeve 14a and an elastic portion 14b made of rubber or the like formed around the cylindrical sleeve 14a. A bolt (not shown) is inserted into the bushing body 14 and screwed into a nut 15 disposed on the upper end side of the bushing body 14, for example, to a bracket (not shown) fixed to the vehicle body, for example, the steering gear box 10. Can be fastened together, whereby the steering device can be attached to the vehicle body. In addition, a fixing device is constituted by a bolt, a nut 15 and a bush body 14 (not shown).
[0007]
[Problems to be solved by the invention]
However, the conventional fixing device has the following problems. The cylindrical sleeve 14 a of the bush body 14 is fixed to the vehicle body via a bolt (not shown), but the steering gear box 10 is attached via an elastic portion 14 b formed around the bush body 14. Therefore, it can move slightly relative to the cylindrical sleeve 14a (that is, a bolt).
[0008]
However, if the steering gear box 10 is relatively movable, for example, when the pinion shaft 13 starts rotating, there is a problem such as a response delay due to the steering gear box 10 moving before the rack shaft moves. Arise.
[0009]
In the prior art, such problems as response delay have been dealt with by increasing the hardness of the elastic portion 14b. However, in recent years, there has been a demand for a higher level of steering performance. A fixing device based on a different idea is required.
[0010]
In response to such a demand, there is an attempt to use only an iron sleeve as a bush body. However, when the bush body is made of only an iron sleeve, it has been found that there is a problem that the nut rotates together with the bolt and is difficult to attach. Such a problem becomes a serious problem when, for example, the steering gear box has to be installed within a very limited working time in a situation where it is difficult for the operator's hand to reach the nut in the assembly line of the vehicle.
[0011]
Therefore, an object of the present invention is to provide a steering gear box fixing device that can provide excellent steering performance and is excellent in assembling.
[0012]
[Means for Solving the Problems]
In order to achieve such an object, a steering gear box fixing device of the present invention includes a cylindrical portion inserted from one of mounting holes of a steering gear box, and a screw portion formed in the cylindrical portion , The portion includes at least a protrusion having a hardness higher than that of the attachment hole of the steering gear box, and when the cylindrical portion is engaged with the attachment hole, the protrusion presses the inner periphery of the attachment hole. A nut portion or a spline tube configured to limit relative rotation between the cylindrical portion and the attachment hole, a bush having a through hole, and being inserted from the other of the attachment holes, and a through hole of the bush And a mounting bolt screwed into the threaded portion in the mounting hole .
[0014]
[Action]
According to the steering gear box fixing device of the present invention, the nut portion or the spline tube has a cylindrical portion inserted from one of the mounting holes of the steering gear box, and a screw portion formed in the cylindrical portion, The cylindrical portion includes a protrusion having a hardness higher than that of at least the mounting hole of the steering gear box, and the protrusion presses the inner periphery of the mounting hole when the cylindrical portion engages with the mounting hole. Accordingly, the relative rotation between the cylindrical portion and the mounting hole is restricted, so that a screw in a rotational direction is applied to the threaded portion by screwing a mounting bolt onto the threaded portion. Even in this case, since the relative rotation between the cylindrical portion and the mounting hole is restricted, it is possible to prevent the screw portion from rotating together and It is possible to perform the mounting easily.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1A is a cross-sectional view of a steering gear box including a fixing device according to a first embodiment of the present invention, and FIG. 1B is a perspective view of a mounting nut. In FIG. 1, the configuration of the steering gear box 10 is the same as that shown in FIG.
[0017]
In the present embodiment, the fixing device includes a nut portion 21, a bush 22, and a mounting bolt 23. As shown in FIG. 1B, a nut portion 21 formed of a material (steel in this embodiment) having a hardness higher than that of the steering gear box 10 (aluminum in this embodiment) includes a hexagonal head 21a, It has a circular flange portion 21b and a spline portion 21c having spline teeth formed on the outer periphery of the lower cylinder. The outer diameter of the spline portion 21 c having spline teeth as protrusions is slightly larger than the inner diameter of the mounting hole 10 a of the steering gear box 10. Further, a female screw portion 21d is formed in the center of the nut portion 21 so as to penetrate vertically.
[0018]
As shown in FIG. 1A, the bush 22 has a flange 21a at the lower end and a through hole 21b at the center.
[0019]
The aspect which attaches the steering gear box 10 using the fixing device of this Embodiment is demonstrated. First, the nut portion 21 is inserted from above, and the spline portion 21c is engaged with the mounting hole 10a. In this case, since the outer diameter of the spline portion 21c is slightly larger than the inner diameter of the mounting hole 10a, it is necessary to push in with a slightly strong force when the nut portion 21 is inserted. Since the hardness of the portion 21c is higher, the spline portion 21c engages with the inner periphery of the mounting hole 10a. It is not necessary to push the nut portion 21 until the flange portion 21b comes into contact with the periphery of the upper surface of the mounting hole 10a, and the male screw portion 23a of the mounting bolt 23 can be engaged with the female screw portion 21d by two to three threads. Once pushed in, the flange portion 21b can be brought into close contact with the periphery of the upper surface of the mounting hole 10a by the screwing of the mounting bolt 23.
[0020]
Further, after inserting the bush 22 from below the mounting hole 10a, the mounting bolt 23 inserted through the mounting hole formed in the vehicle body (not shown) to fix the steering gear box is inserted into the through hole 21b of the bush 22. Then, it is screwed into the female screw portion 21 d of the nut portion 21. When the mounting bolt 23 is screwed as it is, the mounting bolt 23 is screwed with respect to the nut portion 21, and the steering gear box 10 can be mounted on the vehicle body.
[0021]
At this time, since the spline portion 21c of the nut portion 21 bites into the inner periphery of the mounting hole 10a, the nut portion 21 is prevented from rotating together with the screwing of the mounting bolt 23, thereby facilitating mounting. ing. The flange portion 21b of the nut portion 21 comes into contact with the periphery of the upper surface of the mounting hole 10a to prevent further intrusion of the nut portion 21 into the mounting hole 10a, and gives a predetermined tightening torque to the mounting bolt 23, Installation of the steering gear box 10 is completed. Since the gear box 10 attached to the vehicle body by the fixing device of the present embodiment is rigidly supported without an elastic body or the like, it does not move against a steering reaction force from a wheel (not shown). A more excellent steering feeling can be provided.
[0022]
FIG. 2A is a cross-sectional view of a steering gear box including a fixing device according to a second embodiment of the present invention, and FIG. 2B is a perspective view of a mounting nut. In FIG. 2, the configuration of the steering gear box 10 is the same as that shown in FIG.
[0023]
In the present embodiment, the fixing device includes a spline tube 32, a bush 33, and a mounting bolt 33. The spline tube 32 formed of a material (steel) having a higher hardness than the material (aluminum) of the steering gear box 10 has a substantially cylindrical shape as shown in FIG. 2 (b), and has a flange portion 32a at the upper end. The spline part 32b which formed the spline tooth | gear in the outer periphery is formed, and the internal thread part 32c is formed in the inner periphery. The outer diameter of the spline portion 32 b is slightly larger than the inner diameter of the mounting hole 10 a of the steering gear box 10. A through hole 32 a is formed at the center of the spline tube 32.
[0024]
The bush 33 has the same configuration as that of the above-described embodiment, that is, a flange 33a is formed at the lower end and a through hole 33b is formed at the center.
[0025]
The aspect which attaches the steering gear box 10 using the fixing device of this Embodiment is demonstrated. First, the spline tube 32 is inserted from above, and the spline portion 32b is engaged with the mounting hole 10a. In this case, since the outer diameter of the spline portion 32b is slightly larger than the inner diameter of the mounting hole 10a, it is necessary to push in with a slightly strong force when the spline tube 32 is inserted. Since the hardness of the part 32b is higher, it engages so that the spline part 32b may bite into the inner periphery of the attachment hole 10a. It is not necessary to push the spline tube 32 until the flange portion 32a comes into contact with the periphery of the upper surface of the mounting hole 10a. If the male threaded portion 34a of the mounting bolt 34 protrudes above the spline tube 32 by two or three ridges. It ’s enough.
[0026]
Further, after the bush 33 is inserted from below the mounting hole 10a, the mounting bolt 34 inserted through the mounting hole formed in the vehicle body (not shown) to fix the steering gear box 10 is connected to the through hole 33b of the bush 33 and The spline tube 32 is screwed into the female thread portion 32c. When the mounting bolt 34 is screwed as it is, the mounting bolt 34 is screwed with respect to the spline tube 32, and the steering gear box 10 can be mounted on the vehicle body.
[0027]
At this time, since the spline portion 32b of the spline tube 32 bites into the inner periphery of the mounting hole 10a and is given a frictional force to prevent relative rotation, the spline tube 32 is not rotated against the screwing of the mounting bolt 34. Rotation is prevented, thereby facilitating installation. When the flange portion 32a of the spline tube 32 is clamped, a predetermined tightening torque is applied to the mounting bolt 23, and the mounting of the steering gear box 10 is completed. Since the gear box 10 attached to the vehicle body by the fixing device of the present embodiment is also rigidly supported without an elastic body or the like, it does not move against a steering reaction force from a wheel (not shown). A more excellent steering feeling can be provided.
[0028]
FIG. 3 is a cross-sectional view of a steering gear box including a fixing device according to a modification, and is a view similar to FIG. 2A, but omitting nuts and bolts. 2 is different from the embodiment of FIG. 2 in that the spline portion 41c of the spline tube 41 inserted from above is extended instead of inserting the bush from below the attachment hole 10a. Yes. About another point, since embodiment mentioned above is the same as FIG.2 (b), description is abbreviate | omitted.
[0029]
Also in this modified example, when the steering gear box 10 is mounted, the spline portion 41b of the spline tube 41 bites into the inner periphery of the mounting hole 10a, so that a frictional force that prevents relative rotation is applied. Co-rotation of the spline tube 41 is prevented against the screwing (shown), thereby facilitating attachment. Further, the gear box 10 attached to the vehicle body by the fixing device of the present modification is also rigidly supported without an elastic body or the like, so that it does not move against a steering reaction force from a wheel (not shown). It is possible to provide a better steering feeling.
[0030]
The present invention has been described above with reference to the embodiments. However, the present invention should not be construed as being limited to the above-described embodiments, and can be modified or improved as appropriate. For example, by providing a chamfered portion or the like at the lower end of the spline portion, insertion into the mounting hole becomes easier. The number and size of spline teeth can be arbitrarily determined without any particular limitation. Moreover, if the hardness of a spline part is higher than the hardness of the attachment hole of a steering gear box, it can each form using various raw materials. In this embodiment, a female screw is formed in the central through hole of the spline tube. Instead of forming the female screw, the spline tube is sandwiched between a separate nut and a bolt that is screwed to the nut. It is also conceivable to fix it. In such a case, the rotation of the nut is prevented by a frictional force generated between the seating surface of the nut and the surface of the spline tube facing the nut seating surface.
[0031]
【The invention's effect】
According to the steering gear box fixing device of the present invention, the nut portion or the spline tube has a cylindrical portion inserted from one of the mounting holes of the steering gear box, and a screw portion formed in the cylindrical portion, The cylindrical portion includes a protrusion having a hardness higher than that of at least the mounting hole of the steering gear box, and the protrusion presses the inner periphery of the mounting hole when the cylindrical portion engages with the mounting hole. Accordingly, the relative rotation between the cylindrical portion and the mounting hole is restricted, so that a screw in a rotational direction is applied to the threaded portion by screwing a mounting bolt onto the threaded portion. Even in this case, since the relative rotation between the cylindrical portion and the mounting hole is restricted, it is possible to prevent the screw portion from rotating together and It is possible to perform the mounting easily.
[Brief description of the drawings]
FIG. 1 (a) is a sectional view of a steering gear box including a fixing device according to a first embodiment of the present invention, and FIG. 1 (b) is a perspective view of a mounting nut. .
FIG. 2 (a) is a sectional view of a steering gear box including a fixing device according to a second embodiment of the present invention, and FIG. 2 (b) is a perspective view of a mounting nut. .
FIG. 3 is a cross-sectional view of a steering gear box including a fixing device according to a modified example.
FIG. 4 is a front view of a steering device according to the prior art.
5 is an enlarged cross-sectional view of the steering gear box 10 of FIG. 4 taken along the line VV and viewed in the direction of the arrow.
[Explanation of symbols]
10 Steering gear box 10a Mounting hole 21 Nut portion 21c, 32b, 41b Spline portion (protrusion)
22, 33 Bushing 23, 34 Mounting bolts 21d, 32c, 41c Female thread on the inner periphery of the spline tube

Claims (2)

A cylindrical portion inserted from one of the mounting holes of the steering gear box ; and a threaded portion formed in the cylindrical portion, wherein the cylindrical portion has a protrusion having a hardness higher than at least the mounting hole of the steering gear box. And when the cylindrical portion engages with the mounting hole, the protrusion presses the inner periphery of the mounting hole, thereby restricting relative rotation between the cylindrical portion and the mounting hole. The nut or spline tube
A bush having a through hole and inserted from the other of the mounting holes;
Through the through-hole of the bush, a steering gear box fixing device comprising a mounting bolt screwed into the threaded portion within the mounting hole.   The steering gear box fixing device according to claim 1, wherein the nut portion or the spline tube has a flange portion.

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