JPH0748439Y2 - Rack and pinion type steering device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a rack and pinion type steering device, and is particularly suitable as a steering device for a vehicle having a large steering reaction force.

(Prior Art) FIG. 6 and FIG. 7 show a rack and pinion type hydraulic power steering device showing a conventional example, in which a helical pinion 101 interlockingly connected to a steering handle is engaged with the pinion 101. A rack bar 103 having a helical rack 102 formed therein, a rack housing 104 covering the pinion 101 and the rack 102, and a cylinder tube 105 integrated with the rack housing 104 and fitted on the rack bar 103. ing.

A ball joint 106 and a tie rod 10 are provided at both ends of the rack bar 103.
7. Steering wheels (not shown) are interlockingly connected via a knuckle arm or the like, and the steering wheel is steered by movement of the rack bar 103 in the rack axis direction due to rotation of the pinion 101.

An oil chamber 110 is formed between the inner and outer circumferences of the rack bar 103 and the cylinder tube 105 in an oil-tight manner by a pair of seal members 108 and 109.

A piston 111 is provided on the outer periphery of the rack bar 103, and pressure oil is supplied to the one and the other longitudinal sides of the oil chamber 110 partitioned by the piston 111 via pipes 112 and 112 in accordance with the steering direction. When the rack bar 103 is supplied as an auxiliary force for steering operation.

And, the rack bar 103 is the bush 1 on the one side in the axial direction.
It is supported by the inner peripheral surface of the cylinder tube 105 via 13 and is also supported by the rack housing 104 via a support yoke 114 built in the rack housing 104. That is, the rack bar 103 is supported at two points via the bush 113 and the support yoke 114 (note that the rack bar 103 has the inner peripheral surface of the cylinder tube 105 via the seal members 108 and 109 and the seal member 116 on the outer circumference of the piston 111). , But the sealing member is not a supporting point because it is easily deformed).

The position of the support yoke 114 is freely changeable in the meshing adjustment direction of the rack 102 and the pinion 101 (left-right direction in FIG. 6) by advancing and retracting the plug 115 screwed into the rack housing 104 in the screwing direction. ing. As a result, a smooth meshing state can be obtained by changing the position of the rack bar 103 in the meshing adjustment direction of the rack 102 and the pinion 101 via the support yoke 114.

Further, the support yoke 114 is biased by the compression spring 117 and contacts the rack bar 103, thereby allowing the rack bar 103 to move in the meshing adjustment direction due to a manufacturing error in gear cutting or the like, thereby obtaining a smooth meshing state. It is supposed to be.

(Problems to be Solved by the Invention) When the steering device having the above-described configuration is used in a large vehicle, or when the rack bar 103 and the tie rod 107 have a large inclination due to the vehicle layout, the steering wheels are steered. Therefore, since the steering reaction force acting on the rack bar 103 becomes large, it is necessary to take measures to reduce the deformation of the rack bar 103 and improve its strength.

To deal with this, the diameter of the rack bar 103 is increased, or the rack bar 103 is supported not only on the bush 113 but also on the inner peripheral surface of the cylinder tube 105 via a plurality of bushes to increase the number of supporting points. It is possible to make it happen.

However, if the diameter of the rack bar 103 is increased, the rack 102
There is a problem that the entire apparatus unnecessarily increases in size due to an increase in the axial distance between the pinion 101 and the pinion 101 and an increase in the effective length of the tooth portion of the pinion 101.

Further, if the rack bar 103 is supported on the inner peripheral surface of the cylinder tube 105 at a plurality of positions, the rack bar 103 becomes immovable in the mesh adjustment direction, and the mesh adjustment between the rack 102 and the pinion 101 via the support yoke 114 becomes impossible. There is a problem.

(Means for Solving the Problems) An object of the present invention is to provide a rack and pinion type steering device which can solve the problems of the above-mentioned conventional techniques and can be simplified in structure.

A feature of the present invention is that the steering rod includes a pinion for transmitting a steering operation input, a rack bar formed with a rack that meshes with the pinion, and a steering rod interlockingly connected to a steering wheel. Is made cylindrical,
In this steering rod, the rack bar is inserted and a notch exposing the rack is formed,
The stoppers that restrict the relative movement of the rack bar in the axial direction of the rack with respect to the steering rod are screwed into the female threads formed on the inner circumferences of both ends of the steering rod.

Furthermore, it is preferable that a joint for connecting the steering wheel to the steering rod is screwed to the female screw portion formed on the inner circumference of both ends of the steering rod.

(Operation) According to the configuration of the present invention, the deformation and strength of the steering rod and the rack bar due to the steering reaction force can be reduced by increasing the diameter of the steering rod or the number of supporting points of the steering rod. Therefore, there is no need to increase the diameter of the rack bar.

Even if the steering rod cannot change its position in the rack meshing adjustment direction with respect to the pinion due to an increase in the number of supporting points, etc., by changing the position of the rack bar in the meshing adjustment direction with respect to the steering rod, the rack and pinion The meshing adjustment is possible.

Then, a stopper for restricting relative movement of the rack bar in the rack axis direction with respect to the steering rod is screwed into the female screw portion formed on the inner circumference of both ends of the steering wheel, so that the steering operation input from the pinion is input. Due to the transmission, the rack bar and the steering rod move together to steer the steered wheels.

Since the stopper is screwed into the female screw portion on the inner circumference of both ends of the steering rod, the fact that the steering rod has a cylindrical shape for mounting the stopper can be utilized, and the stopper mounting structure can be simplified. It

Further, a joint for connecting the steering wheel to the steering rod is screwed into the female screw portions on the inner circumferences of both ends of the steering rod, so that the joint mounting structure is also simplified.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

1 to 4 show a rack and pinion type hydraulic power steering apparatus for an automobile, in which an input shaft 1 is attached to a steering wheel (not shown).
The helical pinion 2 is connected via the rack pin 4 and the rack bar 4 in which the helical rack 3 that meshes with the pinion 2 is formed.

The input shaft 1 and the pinion 2 are rotatably supported in a rack housing 6 and are connected to each other via a torsion bar 7 (the left side and the right side of the rack housing 6 are left and right in FIG. 1). Since it has a symmetrical structure, a part of the right side is not shown).

Flanges 8 are formed on both sides of the rack housing 6 in the vehicle width direction, and cylindrical cylinder tubes 9 are connected by bolts 10 via the flanges 8 to be integrated. The cylinder tube 9 is fixed to the vehicle body (not shown).

A cylindrical steering rod 11 is inserted into the rack housing 6 and each cylinder tube 9, and the rack bar 4 is inserted into the steering rod 11.

A notch 5 is provided substantially at the center of the steering rod 11 in the vehicle width direction so that the rack 3 is exposed to the outside of the steering rod 11, and the rack 3 exposed thereby meshes with the pinion 2. .

The rack bar 4 and the steering rod 11 are connected to each other so as to move together in the rack axis direction, and the steering wheels (not shown) are linked to each end of the steering rod 11 via ball joints 12. As a result, the rack bar 4 and the steering rod 11 move together in the rack axis direction by the rotation of the pinion 2, and the steering wheels are steered.

Bushings 13 are attached to the outer ends of the cylinder tubes 9 in the vehicle width direction, and a steering rod 11 is slidably inserted in the bushes 13 in the rack axial direction via seal members 14 and 15. .

Further, pistons 16 are provided on both sides of the rack housing 6 on the outer periphery of the steering rod 11, and each piston 16 is slidable in the rack axial direction with respect to the cylinder tube 9 via a seal member 17. .

As a result, a pair of oil chambers 18 closed by the bush 13 and the piston 16 are formed between the inner and outer circumferences of the steering rod 11 and the cylinder tube 9.

By supplying pressure oil to one of the pair of oil chambers 18 depending on the steering direction, the steering rod is passed through the piston 16.
A steering assist force is applied to 11.

Further, in order to adjust the meshing between the pinion 2 and the rack 3, the position of the rack bar 4 can be changed relative to the pinion 2 in the left-right direction in FIG.

That is, peripheral grooves 19 are formed on the outer circumferences of both ends of the rack bar 4 in the axial direction, and an O-ring 20 that is an elastic body is fitted into the peripheral grooves 19, and a ring body 21 is inserted through the O-rings 20.
Is fitted. Further, the O-ring 23, which is an elastic body, is fitted into the circumferential groove 22 formed on the outer circumference of the ring body 21,
The ring body 21 is inserted into the steering rod 11 via the O-ring 23.

As a result, the rack bar 4 moves to the steering rod 11
The O-rings 20 and 23 are supported via the rings 20 and 23, and the O-rings 20 and 23 are elastically deformable to change the position of the pinion 2 and the rack 3 in the meshing adjustment direction.

Further, the rack bar 4 and the steering rod 11 are rotatable relative to each other about the rack axis. That is, the rack bar 4 is slidable relative to the steering rod 11 through the O-rings 20 and 23 and the ring body 21 about the rack axis.

As a result, the force that attempts to rotate the steering rod 11 around the rack axis based on the steering reaction force is prevented from being transmitted to the rack bar 4. Therefore, when the pinion 2 and the rack 3 are helical and mesh with each other while generating a force to rotate the rack bar 4 about the rack axis in the meshing portion, a large steering reaction force acts. Even so, the smooth meshing state between the pinion 2 and the rack 3 can be maintained.

A support yoke 24 is attached to the rack housing 6 as a support member for the rack bar 4. The support yoke 24 has a columnar outer surface, one end of which is in contact with the outer peripheral surface of the rack bar 4 and the other end of which is inserted into the plug 25. The plug 25 is screwed into the rack housing 6 via a male screw on the outer circumference, and the lock nut 26
It is fixed by. Further, a compression spring 27 that engages with the support yoke 24 and the plug 25 is built in the support yoke 24, and biases the support yoke 24 in the contact direction with the rack bar 4.

By moving the plug 25 forward and backward in the direction of screwing it into the rack housing 6, the position of the support yoke 24 can be adjusted and changed in the direction in which the pinion 2 and the rack 3 are adjusted.

By adjusting the position of the support yoke 24, the rack bar 4 is changed in the meshing adjustment direction, and the pinion 2 and the rack 3 are moved.
The meshing adjustment is performed to obtain a smooth meshing state.

Further, since the support yoke 24 is urged in the contact direction with the rack bar 4 via the compression spring 27, the rack bar 4 is allowed to move in the meshing adjustment direction due to a manufacturing error of the gear cutting or the like, and the smoothness is ensured. It is supposed to obtain a good meshing state.

Since the support yoke 24 penetrates the steering rod 11, the steering rod 11 has a through hole 28 for that purpose. This through hole 28 is a long hole elongated in the rack axis direction so as not to interfere with the support yoke 24 when the steering rod 11 moves in the rack axis direction.

The short diameter of the through hole 28 is substantially equal to the outer diameter of the support yoke 24. As a result, the rotation of the steering rod 11 about the rack axis with respect to the pinion 2 is restricted by the outer periphery of the support yoke 24 engaging with the inner periphery of the through hole 28.

In this way, by restricting the rotation of the steering rod 11 with respect to the pinion 2 about the rack axis,
The steering rod 11 is prevented from interfering with the pinion 2.

It should be noted that the structure in which the outer periphery of the plug 25 is engaged with the inner periphery of the through hole 28 as a support member may restrict the rotation of the steering rod 11 with respect to the pinion 2 about the rack axis.

The rack bar 4 and the steering rod 11 are connected so as to move together in the rack axis direction as described above.
Therefore, a stopper for restricting the relative movement of the rack bar 4 in the rack axial direction with respect to the steering rod 11 is provided. In this embodiment, the steering rod
The ball joints 12 at both ends of 11 also serve as the stoppers.

That is, the ball joint 12 includes a ball holding cylinder 29, a ball 30 rotatably held in the ball holding cylinder 29, a block 31 that supports the ball 30 via a seat 33, and the balls 30 and the blocks 31. The cap 32 is screwed into the ball holding cylinder 29 to prevent it from coming off from the ball holding cylinder 29, and a compression spring 34 built in the cap 32 and biasing the block 31 against the ball 30. A connecting shaft 35 is connected and fixed to the ball 30.

The ball joints 12 are screwed into female screw portions 37 formed on the inner circumferences of both ends of the steering rod 11 via male screw portions 36 formed on the outer circumference of the ball holding cylinder 29. The ball joints 12 are in contact with the respective end surfaces of the rack bar 4.

As a result, the relative movement of the rack bar 4 in the rack axis direction with respect to the steering rod 11 is restricted by the ball joint 12 that also serves as a stopper, and the rack bar 4 and the steering rod 11 steer the steering wheel in the rack axis direction. It is supposed to move together in the direction of making it.

Further, by restricting the relative movement of the rack bar 4 with respect to the steering rod 11 in the rack axis direction, it is possible to prevent the handle from rattling during a steering operation.

As described above, the ball joint 12 that also serves as the stopper is attached by screwing into the female screw portions 37 formed on the inner circumferences of both ends of the steering rod 11 by utilizing the fact that the steering rod 11 is cylindrical. This simplifies the structure.

The ring body 21 is sandwiched between the ball joint 12 and the inner peripheral step portion 39 of the steering rod 11, so that the rack bar 4
Relative movement in the rack axis direction is restricted.

Further, a lock nut 38 in contact with the end surface of the steering rod 11 is screwed into the male screw portion 36 of each ball holding cylinder 29 to prevent the ball holding cylinder 29 from loosening. The lock nut 38 is integrally formed with a restricting portion 40 for preventing overstroke that projects radially outward. This regulatory department
The contact of 40 with the bush 13 restricts the steering rod 11 from moving more than necessary in the rack axis direction.

A connecting block 42 is screwed to the connecting shaft 35 via a lock nut 41, and a steering wheel is connected to the connecting block 42 via a knuckle arm or the like. Thus, the toe-in adjustment of the vehicle can be performed by adjusting the screwing amount of the connecting block 42 with respect to the connecting shaft 35.

The pressure oil is supplied to the oil chamber 18 via a rotary valve 43 that is fitted onto the input shaft 1 and is connected to the pinion 2.

That is, the pressure oil supplied from the non-illustrated tank via the pump reaches the oil passage between the inner and outer circumferences of the rotary valve 43 and the input shaft 1 through the supply hole 44 formed in the rack housing 6.
The rack housing 6 is formed with a connection hole 45 communicating from the oil passage to the right steering oil chamber 18 and a connection hole 46 connected to the left steering oil chamber 18. Then, the rotary valve 43 is supposed to rotate together with the pinion 2, and depending on the rotation angle difference between the input shaft 1 and the rotary valve 43 due to the torsion of the torsion bar 7, the rotary valve 43 and the input shaft 1 are provided between the inner and outer circumferences. The oil passage is communicated with the connection hole 45 or the connection hole 46,
Pressure oil is supplied to one of the oil chambers 18 according to the steering direction, and the oil is returned from the other oil chamber 18 to the tank through the discharge hole 47 formed in the rack housing 6.

In order to communicate the connection holes 45 and 46 with the oil chamber 18, pipes are not used in the above embodiment, and blocks 48 integrated with the cylinder tube 9 and the rack housing 6 are provided on both sides of the rack housing 6 in the vehicle width direction. An oil passage hole 49 that connects the connection holes 45 and 46 with the oil chamber 18 is formed in each block 48.

A bellows cover 50 made of an elastic material is provided so as to cover the steering rod 11 and the ball joint 12 protruding from both ends of the cylinder tube 9, and the bellows cover 50 made of an elastic material is attached to the outer periphery of the connecting shaft 35, the ball holding cylinder 29 and the cylinder tube 9. It is fixed by a wheel.

According to the above steering device, the steering rod 11
Will be supported at three places via the support yoke 24 and the two bushes 13. Compared to the conventional support at two places via the support yoke and one bush, the supporting place is And the bending deformation of the steering rod 11 and the rack bar 4 due to the steering reaction force is reduced,
It is suitable for use in large vehicles with large steering reaction force.

Further, in order to improve the strength against the steering reaction force and reduce the deformation, it is sufficient to increase the diameter of the steering rod 11, and it is not necessary to increase the rack bar 4, and the axial distance between the pinion 2 and the rack 3 and the pinion. The effective length of 2 can be invariable,
The entire device does not unnecessarily increase in size.

Further, even if the steering rod 11 cannot be repositioned in the meshing adjustment direction between the pinion 2 and the rack 3 due to the increase in the number of supporting portions of the steering rod 11, the rack bar 4 can be repositioned in the meshing adjustment direction so that the smooth movement can be achieved. It is possible to obtain a good mesh state.

The present invention is not limited to the above embodiment.

For example, in the above embodiment, the ball joint 12 also serves as a stopper that restricts the relative movement of the rack bar 4 and the steering rod 11 in the rack axial direction, but as shown in FIG. May be provided with a stopper 60 separately.

That is, each stopper 60 has a male screw portion 61 formed on the outer circumference thereof, is screwed into female screw portions 37 formed on the inner circumferences of both ends of the steering rod 11, and contacts both ends of the rack bar 4, whereby the rack bar 4 and the steering rod 4 are in contact with each other. Relative movement with respect to the rack axis direction with 11 is regulated. A tool engaging hole 62 is formed in the stopper 60.

Further, in the embodiment of FIG. 5, instead of the ring body 21 in the above embodiment, a ring portion 63 is integrally formed with the stopper 60, a circumferential groove 22 is formed in the ring portion 63, and an O ring 23 is fitted therein. As a result, the ring body 21 has the same function.

Further, in the above embodiment, the connection block for the connection shaft 35
The toe-in adjustment of the vehicle was possible by adjusting the screwing amount of 42, but in this embodiment, since the ball joint 12 does not need to have a stopper function, the ball joint 12 is screwed into the steering rod 11. It is said that toe-in adjustment is performed by adjusting the amount. Therefore, it is not necessary to separate the connecting shaft 35 and the connecting block 42 from each other. Therefore, the connecting shaft 35 and the connecting block 42 are suitable for the case where the connecting shaft 35 and the connecting block 42 are integrally molded to be downsized and there is no space.

The other structure is the same as that of the above-described embodiment, and the same portions are denoted by the same reference numerals.

Further, in the above embodiment, the joint 12 is a ball joint,
For example, a pin joint may be used.

Further, the number of supporting points of the steering rod 11 may be increased or decreased as compared with the above embodiment.

Further, the present invention can be applied to a manual steering device or an electric power steering device instead of the hydraulic power steering device.

(Effect of the Invention) According to the present invention, since the steering rod has a cylindrical shape and the rack bar is inserted in the steering rod, the deformation due to the steering reaction force and the improvement in strength can be achieved by reducing the diameter of the steering rod. Can be performed by increasing the number of racks and supporting points, and it is not necessary to increase the diameter of the rack bar.
It is possible to prevent the entire device from unnecessarily increasing in size.

The stopper that restricts the relative movement of the rack bar and the steering rod in the rack axis direction is screwed to the female screw portion on the inner circumference of both ends of the steering rod by utilizing the fact that the steering rod is cylindrical. Therefore, the structure is simplified.

Further, the structure can be simplified by screwing a joint for connecting the steering wheel to the steering rod to the female screw portion on the inner circumference of both ends of the steering rod.

[Brief description of drawings]

1 to 5 relate to an embodiment of the present invention. FIG. 1 is a front sectional view of a steering device, FIG. 2 is a side sectional view of the steering device, and FIG. 3 is a plane sectional view of a main part of the steering device. 4 and 5 are a rear view of the main part of the steering device, FIG. 5 is a front sectional view of the main part of the steering device according to a different embodiment, and FIG. 6 is a side sectional view of the conventional steering device.
FIG. 7 is a partially cutaway front view of a conventional steering device. 2 ... Pinion, 3 ... Rack, 4 ... Rack bar, 5 ... Notch, 11 ... Steering rod, 12 ... Ball joint, 37 ... Female screw part, 60 ... Stopper.

Claims (2)

[Scope of utility model registration request] 1. A pinion for transmitting a steering operation input, a rack bar in which a rack that meshes with the pinion is formed, and a steering rod that is interlockingly connected to a steering wheel, and the steering rod has a tubular shape. The rack bar is inserted into the steering rod, and a notch exposing the rack is formed in the steering rod, and the rack bar of the rack is attached to the female thread portion formed on the inner circumference of both ends of the steering rod. A rack and pinion type steering device characterized in that a stopper for restricting relative movement in the axial direction is screwed. 2. A joint for connecting a steering wheel to a steering rod is screwed to female screw portions formed on the inner circumferences of both ends of the steering rod.
The described rack and pinion type steering device.