JPH11222141A - Rack and pinion type steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rack and pinion type steering device to simplify struc ture, eliminate a need for strict management, and to prevent the generation of uncomfortable noise during running of an automobile. SOLUTION: A rack and pinion type steering device 10 fundamentally comprises a pinion shaft 56 to have a pinion 71 arranged at a pinion case 55 and be rotatably held; a rack shaft 61 having a rack 72 engaged with the pinion 71 of the pinion shaft 56; a plunger 5 to slidably press a rack shaft 61 in the pinion case 55; and a spring 63 to press the plunger 5 against the rack shaft 61. The plunger 5 forms division structure consisting of a plug 1 movable in the expansion direction of the spring 63; and a plurality of pistons 4 movable approximately in an orthogonal direction to a direction in which the plug 1 is movable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rack and pinion type steering device for an automobile.
More specifically, the present invention relates to a structure of a plunger for adjusting meshing between a rack and a pinion in a rack and pinion type steering device.

[0002]

2. Description of the Related Art An automobile shown in FIG. 4 is an automobile having a steering apparatus 60 of a general rack and pinion type. The arrangement position of the steering device 60 is between the steering column 54 and the tie rod 53, and the steering column 54 is connected to the steering column 54 by a pinion shaft 56. The function of the steering device 60 is to transmit the operating force of the steering 51 transmitted via the steering column 54 to the tie rod 53 to steer the front wheels 52. FIG. 5 is a detailed view of a portion A in FIG.
FIG. 3 is a detailed view of a steering device 60 and a tie rod 53. The steering device 60 transmits the steering operation force input to the pinion shaft 56 in the pinion case 55 to the rack shaft 61 to change the direction in a substantially right angle direction. Then, at the connecting portion between the rack shaft 61 and the tie rod 53,
A steering boot 68 is provided. FIG. 6 shows a cross section BB of the steering device 60 in FIG.
This steering device 60 holds a pinion shaft 56 and a rack shaft 61 in a pinion case 55. A helical gear is used for the tooth shapes of the rack 72 provided on the rack shaft 61 and the pinion 71 of the pinion shaft 56. The rack 72 and the pinion 71
Is adjusted by transmitting the pressing force of the spring 63 to the rack shaft 61 via the plunger 62 so that the backlash becomes zero. The spring 63 is held between the spring 63 and the plunger 62 by attaching a rack damper screw 64 to the pinion case 55. Rack damper screw 64 has cap 65
Covered by. In addition, the pinion shaft 56 is
9 and 66 are held at two places. The bearing 59 is pressed against the pinion case 55 by the pinion plug 67. Sealing of the lubricating oil in the shaft rotating portion of the pinion shaft 56 is performed by an oil seal 58. Further, the pinion shaft 56 is covered with a boot 57 on the steering column 54 side from the oil seal 58.

[0003] As another technology relating to a rack and pinion type steering device, Japanese Utility Model Application Publication No. Sho 6
It is disclosed in, for example, Japanese Patent Publication No. 1-4440. The technology disclosed in this publication has basically the same components and functions as the above-described technology, but differs in the detailed shape.

[0004]

The plunger in the conventional rack-and-pinion type steering device is fitted into the fitting hole of the pinion case with a loose fit. For this fitting, in order to efficiently transmit the pressing force of the spring to the rack shaft, it is required that interference be set so that the plunger moves smoothly. Generally, in order to smoothly move the plunger, the fitting of the fitting hole between the plunger and the pinion case may be loosened. However, when an automobile equipped with the rack and pinion type steering device travels on the road, vibrations due to unevenness of the road surface are transmitted from the front wheels to the plunger via a meshing portion between the rack and the pinion. You. The vibrations transmitted to the plunger due to the unevenness of the road surface vibrate the plunger in the fitting hole of the pinion case, and the plunger hits the wall of the fitting hole, which is likely to cause a tapping sound. As a result, this hammering sound resonates outside the vehicle as an unpleasant noise. This phenomenon tends to be particularly pronounced when the road is unpaved and rough. For this reason, in general, as a countermeasure against tapping noise, the size, processing accuracy, etc. are strictly controlled by a method such as selective fitting of the fitting hole of the plunger and the pinion case to prevent occurrence of tapping noise. Need to do so. As another method of preventing tapping noise, an elastic body such as an O-ring is attached to the outer periphery of the plunger so that even if the plunger vibrates in the fitting hole of the pinion case, the fitting hole is directly inserted into the fitting hole. Sometimes they take steps to avoid hitting the wall. However, all of the methods require strict management of parts from manufacturing to assembly, and require a large number of management steps. Mounting an elastic body such as an O-ring not only increases the number of parts but also increases the number of assembly steps. Therefore, at present, a large amount of cost is required to take measures to prevent hammering.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention has a plunger of a rack and pinion type steering device having a divided structure. More specifically, the rack and pinion type steering device of the present invention includes a pinion shaft having a pinion and rotatably held by a pinion case, and a rack shaft having a rack that meshes with the pinion of the pinion shaft. The basic configuration is such that a plunger that slidably presses the rack shaft in the pinion case and a spring that presses the plunger toward the rack shaft are provided. The present invention provides a plunger for a rack-and-pinion type steering device having such a basic structure, a plug that can move in a direction in which a spring expands and contracts, and one or more plugs that can move in a direction substantially perpendicular to the moving direction of the plug. And a piston. Although the number of pistons is divided into two in the embodiment described below in detail, it is merely an example, and is not limited to two. The number of pistons may be two or more, or may be such that only one piston can move in a direction perpendicular to the direction of movement of the plug.

[0006]

1 to 3 show an embodiment of the present invention. FIG. 1 is an enlarged view of a main part of a rack and pinion type steering device to which the present invention is applied, FIG. 2 is a detailed view of a plunger in a rack and pinion type steering device to which the present invention is applied, and FIG. FIG. 10 is a view showing another embodiment of the plunger in the rack and pinion type steering device described above.

The vehicle to which the steering device 10 of the present invention is applied is a vehicle in which the steering device 10 is of a rack and pinion type, like the vehicle shown in the conventional example of FIG. Although the basic components and their functions are the same as those of the conventional steering device 60 shown in FIG. 6, a feature of the steering device 10 of the present invention lies in the structure of the plunger 5. Details are as shown in FIG. In FIG. 1, in order to clarify the difference between the steering device 10 of the present invention and the conventional steering device 60, FIG. 1 is an enlarged view of a main part, and only the changed portions are denoted by new reference numerals. The same reference numerals as those in FIGS. 4 to 6 are used for the parts without.

The overall structure of the steering device 10 of the present invention will be described. First, regarding the pinion shaft 56, the pinion shaft 56 has a ball bearing,
It is held at two places by bearings 59 and 66 such as a bush and a needle bearing. The pinion shaft 56 is provided with a pinion 7 having a helical gear tooth profile.
1 is provided. The position of the pinion 71 on the pinion shaft 56 is determined by the two bearings 59 and 66 described above.
The vicinity of the bearing 66 is opposite to the side on which the steering operation force is input to the pinion shaft 56. The bearing 59 on the input side of the steering operation force to the pinion shaft 56 is pressed against the pinion case 55 by fixing the pinion plug 67 to the pinion case 55 by press fitting or the like. On the other hand, the rack shaft 61 is provided with a rack 72 in the form of a helical gear, which meshes with the pinion 71 described above. The engagement between the rack 72 and the pinion 71 is achieved by applying the pressing force of the spring 63 via the plunger 5 to the rack shaft 61.
The transmission is adjusted to prevent backlash. This is to improve the operation feeling of the steering wheel 51. Spring 63
Is held between the pinion case 55 and the plunger 5 by fixing the rack damper screw 64 with a screw or the like. And the rack damper screw 64 is a cap 6
The cover 5 is covered by fitting it into the pinion case 55 by press fitting or the like. Sealing of lubricating oil for lubricating the engaging portion between the rack 72 and the pinion 71 and the sliding portions of the bearings 59 and 66 is performed by an oil seal 58. The oil seal 58 is fixed to the pinion plug 67 by press fitting or the like. In addition, mud generated by driving the vehicle to the oil seal 58,
In order to prevent the adhesion of dust, etc., the pinion case 55
A boot 57 is disposed on the steering column 54 side. The rack 72 and the pinion 71 of the present embodiment are used.
Is a helical gear, but the rack 72 and the pinion 71 may be designed as a spur gear or the like, and the tooth form is not particularly limited.

The structure of the plunger 5 which is a feature of the steering device 10 of the present invention will be further described with reference to FIG. The plunger 5 has a three-part structure including a plug 1 movable in the direction in which the spring 63 expands and contracts, a piston upper 2 and a piston lower 3 movable in a direction substantially orthogonal to the direction in which the plug 1 can move. .
The piston upper 2 and the piston lower 3 are fitted in fitting holes 73 provided in the pinion case 55. One end is in contact with the rack shaft 61 in a slidable state. The other end receives the pressing force of the spring 63 via the plug 1 and transmits this pressing force to the rack shaft 61. Plug 1 and piston upper 2, and
The plug 1 and the piston lower 3 are in contact at the tapered surface 6 and the tapered surface 7.

Next, the operation of the plunger 5 will be described. The plug 1 tries to move in the direction C by receiving the pressing force of the spring 63 in the fitting hole 73. Since the plug 1 and the piston upper 2 and the piston lower 3 are in contact with each other on the tapered surface 6 and the tapered surface 7, the piston upper 2 and the piston lower 3 The upper 2 also moves in the D direction, and the piston lower 3 also moves in the E direction. That is, the movement of the piston upper 2 and the piston lower 3 is caused by the pressing force of the spring 63 transmitted through the plug 1 and the fitting hole 73.
With the interference set to zero, the rack shaft 61 is pushed. Therefore, the piston upper 2
And the gap where the piston lower 3 vibrates is zero,
The meshing can be adjusted so as to eliminate the backlash between the rack 72 and the pinion 71 without generating a hitting sound.
For this reason, the steering operation feeling can be improved.

FIG. 3 is a view showing another plunger 5 'in the rack and pinion type steering apparatus 10 to which the present invention is applied. The difference between the structure of the plunger 5 'and the structure of the plunger 5 shown in FIG. 2 lies in how the piston 4' is divided. The plunger 5 shown in FIG. 2 has a structure in which the piston 4 is divided into the piston upper 2 and the piston lower 3 with the division surface of the piston 4 being orthogonal to the longitudinal direction of the pinion shaft 56. However, the plunger 5 'shown in FIG. 3 has a structure in which the dividing surface of the piston 4' is parallel to the longitudinal direction of the pinion shaft 56, and the piston 4 'has a dividing structure of the piston right 2' and the piston left 3 '. The tapered surface 6 ′ and the tapered surface 7 ′ of the plug 1 ′ are formed so as to be in contact with the piston right 2 ′ and the piston left 3 ′, like the plunger 5.

The operation of the plunger 5 'is basically the same as the operation of the plunger 5. The difference is
It is only the movement direction of the piston 4 '. Specifically, when the plug 1 'moves in the direction C' shown in FIG. 3 under the pressing force of the spring 63, the piston right 2 'moves in the direction D' and the piston left 3 'moves in the direction E'. Then, the gap with the fitting hole 73 is reduced to zero.

The above is the embodiment in which the pistons 4 and 4 'are divided into two parts. However, it is possible to divide these pistons 4, 4 'into two or more. For example, the piston 4 in FIG.
Is divided into two or more portions, the plug 1 and the piston 4 may be formed with taper surfaces of a number corresponding to the number of divisions of the piston 4. In this case, the operation is the same as that of the plunger 5 having the above-described two-part structure. Since these structures and operations can be easily interpreted from the piston 4 having the two-part structure shown in FIG. 2 and the like, illustration is omitted in this specification.

[0014]

According to the present invention, the plunger can be easily prevented from vibrating in the fitting hole of the pinion case, and the vibration causes the plunger to move into the wall of the fitting hole of the pinion case. Can be prevented from being uncomfortable. This effect is remarkable when the road is an unpaved rough road, and the commercial value of an off-road vehicle mainly driving on a rough road can be particularly improved. In addition, the present invention increases the spring load and increases the pressing force applied to the plunger to prevent the tapping noise. No force is required, and steering operation feeling is not impaired. Furthermore, in order to prevent the tapping sound, the fitting hole between the plunger and the pinion case is selected and strict control of the parts from manufacturing to assembly by fitting or the like requires a great deal of man-hours. Then there is no need. Also, as compared with a method in which an elastic body such as an O-ring is attached to the outer periphery of the plunger to prevent a tapping sound, the number of assembling steps does not increase, and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is an enlarged view of a main part of a rack and pinion type steering device to which the present invention is applied.

FIG. 2 is a detailed view of a plunger in a rack and pinion type steering device to which the present invention is applied.

FIG. 3 is a diagram showing another embodiment of the plunger in the rack and pinion type steering apparatus to which the present invention is applied.

FIG. 4 is a diagram showing an automobile as a conventional rack-and-pinion type steering device.

FIG. 5 is a detailed view of a portion A in FIG. 4;

FIG. 6 is a sectional view taken along the line BB in FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plug 4 Piston 5 Plunger 10 Steering device 55 Pinion case 56 Pinion shaft 61 Rack shaft 63 Spring 71 Pinion 72 Rack

Claims (1)

[Claims] 1. A pinion case, a rotatably held pinion shaft having a pinion in the pinion case, a rack shaft having a rack that meshes with the pinion of the pinion shaft, and the rack in the pinion case. A rack and pinion type steering device comprising a plunger that slidably presses a shaft and a spring that presses the plunger toward the rack shaft, wherein the plunger is movable in a direction in which the spring expands and contracts. A rack and pinion type steering device, comprising: a plug having at least one movable plug and at least one piston movable in a direction substantially perpendicular to a moving direction of the plug.