JPH0338153B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mesh adjustment device for a steering gear of a vehicle, which comprises a rack shaft and a plurality of pinions meshing with the rack shaft at different angles.

A driven pinion is engaged with the rack shaft of a rack-pinion type steering gear that constitutes the main part of the front wheel steering system, and the rotation required for rear wheel steering is extracted from the input shaft connected to the driven pinion via a linkage shaft, and the input shaft is connected to the input shaft. The joint member is loosely fitted to the provided eccentric pin and connects and supports the left and right rear wheel steering tie rods.The horizontal and vertical rocking caused by the crank rotation of the eccentric pin causes the front and rear wheels to move in proportion to the steering angle. A vehicle steering system that simultaneously steers the front wheels and rear wheels by changing the steering ratio of the vehicle (patent application)
No. 57-93394, etc.) was previously provided by the present applicant.

According to such a steering device, it is possible to steer the rear wheels in the same direction as the front wheels by operating a small steering angle of the steered wheels, and it is also possible to steer the rear wheels in the opposite direction by operating a large steering angle, thus making it possible to drive at high speed. In addition to improving the steering performance inside the U
When making a turn or entering or exiting a parking lot, the steering angle is increased to obtain a small turning radius, which improves maneuverability of the vehicle.

By the way, the steering gear forms a drive pinion that rotates in conjunction with the steering wheel, and a rack that meshes with the drive pinion,
It consists of a rack shaft that forms another rack and a driven pinion that meshes with the other rack of the rack shaft, and both pinions have different angles when viewed from the side from the axial end surface of the rack shaft due to the structure of the vehicle. They are assembled so as to mesh with the respective easy shafts.

Therefore, in the past, in order to restrict the deflection of the rack shaft and ensure meshing with each pinion, a compression means was attached between the rack shaft and the gearbox on the back of one of the racks with which the drive pinion meshed, and the drive pinion Another clamping means is attached between the same rack shaft and the gearbox on the back side of the other rack that engages with the other rack, and by adjusting both clamping means by rotating them respectively, the rack shaft is engaged with the rack shaft at different angles. The engagement between the two pinions and each rack is maintained separately. This was already proposed by the present applicant in Japanese Patent Application No. 3727/1983.

However, as described above, it is difficult to maintain the engagement between both pinions and the rack shaft by adjusting the two pressing means respectively.

The present invention has been made in view of the above, and its purpose is to facilitate adjustment for maintaining engagement between at least one of both pinions and the rack shaft, and to require two pressing means. To provide a mesh adjustment device for a steering gear of a vehicle, which ensures mesh retention without any problems.

In order to achieve such an object, the present invention provides an eccentric ring between, for example, one end of the rack shaft and a gearbox, and the gearbox is provided with two adjuster screws for rotationally holding the eccentric ring. The gist of the invention is that an adjustment mechanism consisting of the following is attached, and the eccentricity of the eccentric ring is used to hold the rack shaft in a proper meshing position with one of the pinions.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described in detail below along with the configuration of a front and rear wheel steering system for a vehicle. FIG. 1 is a perspective view showing a schematic configuration of a front and rear wheel steering system, FIG. 2 is an exploded perspective view of the main parts of the rear wheel steering system, and FIG. 3 is a sectional view of the main parts in an assembled state.

A pinion shaft 21 is connected to the lower end of the handle shaft 2 of the steering wheel 1 through a universal joint 3, and the lower part of the pinion shaft 21 is connected to a gear box 2 of a rack-pinion type steering gear for steering the front wheels.
A drive pinion (not shown) meshes with a rack 24 formed in the right half of the rack shaft 23. This rack 24 is formed so as to face upward and forward.

A cylinder barrel 27 is installed horizontally in the gearbox 20, and the rack shaft 23, which is a piston rod that slides inside the cylinder barrel 27, and the cylinder barrel 27 constitute a power cylinder as is known in the art. A rack 25 is also formed in the left half on the left side of the power cylinder, and a driven pinion 28 is meshed with the rack 25. This rack 25 is formed so as to face upward.

By the way, the upper part of the shaft 21 of the drive pinion is tilted backward and slightly to the right, and the shaft 29 of the driven pinion 28 is arranged approximately horizontally in the front-rear direction, but the rear part is tilted slightly to the right, so these drive pinions and the driven The teeth of both the pinion and the racks that mesh with each other are helical teeth.

Tie rods 4, 4 are connected to both ends of a rack shaft 23 protruding from the left and right ends of the gearbox 20, respectively, and knuckle arms 5, 5 are connected to the outer ends of the tie rods 4, 4, and the front wheels 7, 7 are connected to the knuckle arms. Wheels 6, 6 protruding outward from 5, 5
is supported by

As is known, the front wheels are steered by the left and right movement of the rack shaft 23, and at this time the steering torque is reduced by the power cylinder.

On the other hand, the rear part of the shaft 29 of the driven pinion 28 protrudes rearward from the gearbox 20 and connects to the universal joint 3.
A long linkage shaft 32 is connected approximately linearly through a universal joint 3 at the rear end of the linkage shaft 32.
An input shaft 34 is connected via 3.

The input shaft 34 is arranged in alignment with the left-right center line of the vehicle, and is attached to a holder 37, a plurality of ring rubbers 38 (in the figure, five wheels) attached to the outer periphery of the holder 37, and further attached to the outer periphery of the ring rubber 38 to the floor panel of the vehicle body. It is a rotating member supported by a fixed holder outer 39, and an eccentric flange 35 is provided at the rear end of this input shaft 34.
is formed.

An eccentric pin 36 is formed on the rear surface of the eccentric flange 35 and projects further rearward, and a joint member 41 is loosely fitted and supported at the center of the eccentric pin 36 .

The joint member 41 is formed to be short in the vertical direction and long in the horizontal direction.
The inner ends of left and right tie rods 8, 8 are connected and supported via ball joints 9, 9 at the left and right ends of the front surface 42 of the main body 1, respectively, and near the center of the rear surface 43, the tip of an arm member 44 is connected to two left and right ends. They are connected by bolt connections 45, 45. The base of this arm member 44 extends to the right in a substantially horizontal manner, and the arm member 44 is swingably supported by a link 46 that is pivotally supported by a link bracket 47 hanging from the floor panel of the vehicle body. As a result, the joint member 41
is kept in a horizontal state and its swinging is restricted.

Further, knuckle arms 11, 11 are connected to the outer ends of the left and right tie rods 8, 8, which are connected and supported by the joint member 41.
The rear wheel 1 is mounted on the axle 12, 12 which protrudes outward from the wheel 1.
3,13 are supported.

In the figure, 14 is a damper unit for the front wheel, 15 is the same radius slot, and 16 is the same lower arm.
Further, 17 is a damper unit for the rear wheel, 18 is the same radius slot, and 19 is the same lower arm.

When the steering wheel 1 is operated, the driven pinion 28 meshes with the rack 25 on the left half of the steering gear due to the left-right movement of the rack shaft 23 of the steering gear.
The rotation necessary for steering the rear wheels is output, and the rotation is inputted to the input shaft 34 of the rear wheel steering system via the linkage shaft 32, so that the input shaft 34 rotates to either the left or right.

As the input shaft 34 rotates, the eccentric pin 36 integrally provided at the rear end performs crank rotation, and is moved in a direction perpendicular to the input shaft 34 (vertically upward in the embodiment).
The joint member 41, tie rod 8,
8. Rear wheel 13 via nutkl arms 11, 11,
13 is steered.

That is, at a small steering angle of 1/2 rotation from the initial neutral position of the eccentric pin 36, the rear wheel 13 is in the same phase as the front wheel 7,
At a large steering angle exceeding 1/2 rotation, the steering will be in the opposite phase.

In the present invention, the steering gear of the front and rear wheel steering device described above is provided with a mesh adjustment device which will be described in detail below. This will be explained based on FIGS. 4 to 8. Figure 4 is a partially cutaway bottom view of the steering gearbox, Figure 5 is a longitudinal cross-sectional side view of the driven pinion and rack, Figure 6 is an end view of the gearbox seen from the left side of the rack shaft, and Figure 7 is the main body. FIG. 8 is a vertical sectional side view of the mesh adjustment device according to the invention, and is an exploded perspective view of the gearbox portion.

Rack shaft 23 inserted horizontally into the cylinder barrel 27 installed horizontally in the steering gear box 20
A piston 23a is fixedly installed on the outer periphery _{of the piston 23a, and left and right oil chambers S 1 and S 2 are} formed in the cylinder barrel 27 by the piston 23a. Power assist is provided in a known manner by selectively supplying pressurized oil through the motor.

First, the right rack 2 where the drive pinion engages.
A pusher (not shown) is in contact with the periphery of the rack shaft 23 on the rear side of the rack 4, and the pusher elastically urges the rack shaft 23 toward the drive pinion by the elastic force of a spring (also not shown). The spring is an adjustment bolt 5 screwed into the rear part of the gearbox 20.
The elastic force is adjusted by adjusting the forward and backward movements of 1, and the meshing retention adjustment between the drive pinion and the rack 24 is performed by the elastic means consisting of a presser, a spring, and an adjuster bolt 51 similar to the known ones. Ru.

On the other hand, a stopper screw 52 is connected to the rack shaft 23 by about 0.5 mm at the bottom of the gearbox 20 on the back side of the left rack 25 where the driven pinion 28 meshes.
The stop pass screw 52 is screwed into the screw 52 with a gap C between the screws 53 and 53,
Initialize. A ring groove 52a is formed on the outer periphery of this stop screw 52.
2a contains an O-ring 54 and a cap ring 55.
is fitted, thereby creating a seal.

A mechanical seal 56 and a needle thrust bearing 57 are interposed between the upper outer circumference of the driven pinion shaft 29 and the gear box 20, and a ball bearing 58 is interposed between the lower outer circumference and the gear box 20. A cap screw 61 is screwed into a hole 59a at the front of the gear box 20 formed coaxially with the pinion shaft 29, and the cap screw 61 is connected to the lock nut 6.
2, it is in contact with the ball bearing 58.
A ring groove 61a is formed on the outer periphery of the cap screw 61, and an O-ring 63 is fitted into the ring groove 61a.
A cap-shaped cover 64 is placed over the protrusion 59 surrounding the hole 59a, and an outer peripheral piece 64 of the cover 64 is attached.
A is attached to the narrow diameter portion 59b of the protrusion 59 with a hook.

An eccentric ring 70 is interposed between the inner periphery of the left end of the gearbox 20 and the outer periphery of the rack shaft 23. The eccentric ring 70 has an eccentric amount ε of about 1 mm between an outer circumference 71 that slides on the inner circumference of the gearbox 20 and an inner circumference 72 that slides on the outer circumference of the rack shaft 23.
It is constructed eccentrically with .

There are two recesses 7 on the outer periphery of the eccentric ring 70.
3, 73 are formed, and as shown in the figure, the recesses 73, 73 are formed so as to face in the same direction and are adjacent to each other.

Further, two holes 75, 75 are formed in the lower part of the left end portion of the gearbox 20, spaced apart from each other in the vertical direction, and adjusting screws 76, 76 are inserted into the respective holes 75, 75 from below. The tips of the adjusting screws 76, 76 face into the recesses 73, 73 formed on the outer periphery of the eccentric ring 70, respectively, and these adjuster screws 76, 76 are screwed into the recesses 73, 73 with lock nuts 77, 77, respectively. It is in contact with the bottom surface of 73.

The fitting position of the eccentric ring 70 into the gear box 20 is determined by making the inner circumference of the gear box 20 and the outer circumference of the eccentric ring 70 different in diameter in the length direction. Further, a retainer 78 is in contact with the outer end surface of the eccentric ring 70.
By fitting the snap spring 79 to the outer periphery of the gearbox 20 and the inner periphery of the gearbox 20,
0 is prevented from being removed.

By the way, in FIGS. 5 to 7, the right side of the drawing is the lower side of the gearbox 20, and the upper side of the drawing is also the rear side.

When adjusting the meshing between the driven pinion 28 and the rack 25 that meshes with it, one of the two adjuster screws 76, 76 is screwed forward and the other is moved backward, whereby the eccentric ring 70 gradually rotates inside the gear box 20, and the rack shaft 2 is supported on the inner circumference 72 of the eccentric ring 70.
3 gradually moves toward the driven pinion 28 according to the amount of eccentricity (0 to 1 mm) of the eccentric ring 70, and thus the driven pinion 2
When the left rack 25 is securely engaged with the lock 8, the adjustment screws 76, 76 stop moving forward and backward, and the lock nuts 77, 77 are tightened, respectively.

In this way, the driven pinion 28 and the rack 25 meshing therewith are maintained in mesh. In this case, the rack 25 with which the driven pinion 28 meshes
On the back side of the holder, the stopper screw 52 faces below the rack shaft 23 with an interval C of approximately 0.5 mm as described above, so that the rack shaft 23 is
The deflection of is regulated by a stop screw 52.

The engagement between the driven pinion 28 and the rack 25 is maintained by an eccentric ring 70 instead of the conventional elastic means, and the eccentric ring 70 carries a bearing near the left end of the rack shaft 23, which is to the left of the rack 25. Since the ring 70 ensures the above-mentioned meshing retention, the bearing adjustment can be performed at the same time, and therefore the meshing adjustment work becomes easy.

In addition, the drive pinion and the rack 2 that mesh with it.
4 may be maintained by an eccentric ring as described above instead of the elastic force means.

As is clear from the above description, according to the present invention, an eccentric ring is interposed between the rack shaft of the steering gear and the gearbox, and the gearbox is provided with an adjustment mechanism for rotationally adjusting and holding the eccentric ring. In order to maintain the meshing of at least one of the plurality of pinions meshing with the rack shaft at different angles when viewed from the axial end surface of the rack shaft in a side view of the steering gear of a vehicle, This adjustment can be made simultaneously with the adjustment of the rack shaft bearing, and moreover, the above can be easily done without requiring a plurality of pressure means.

[Brief explanation of drawings]

The drawings show a preferred embodiment of the present invention, and FIG. 1 is a perspective view showing a schematic configuration of a front and rear wheel steering device;
Fig. 2 is an exploded perspective view of the main parts of the rear wheel steering system, Fig. 3 is a vertical side view of the main parts in the assembled state, showing the joint member rotated 90 degrees, and Fig. 4 is the steering gear. A partially cut-away bottom view of the gear box showing the drive pinion shaft portion in a nearly horizontal rear rotational view; FIG. 5 is a sectional view taken along the line 5-5 in FIG. 4; FIG. 6 is a left side view of the gear box; 7 is a sectional view taken along the line 7--7 in FIG. 4, and FIG. 8 is an exploded perspective view of the gearbox section. In addition, 20 in the drawing is a steering gear box, 2
1 is the drive pinion shaft, 23 is the rack shaft, 2
4, 25 are easy, 28 is driven pinion, 7
0 is an eccentric ring, and 76 and 77 are adjustment mechanisms.

Claims (1)

[Claims] 1. A drive pinion that rotates in conjunction with the steering wheel, a rack shaft formed with a rack that meshes with the drive pinion, and a rack formed on the rack shaft that is different from the above and meshes with the drive pinion at a different angle. It consists of a driven pinion that
In a vehicle steering gear that inputs the rotation of the driven pinion to a rear wheel steering system,
An eccentric ring is interposed between the rack shaft and the gearbox, and an adjustment mechanism for rotationally holding the eccentric ring is provided, and by adjusting the rotation of the eccentric ring, the rack shaft is meshed and held with one of the pinions. A mesh adjustment device for a vehicle steering gear configured as follows.