JPH04118371A - Rack-and-pinion type steering gear - Google Patents

Abstract

PURPOSE:To realize the miniaturization of a steering gear by forming a steering rod into tubularity, inserting a rack bar into this steering rod, and connecting this rack bar to the steering rod so as to travel together with a rack in the axial direction. CONSTITUTION:Each tubular cylinder tube 9 is connected to each flange installed at both sides in the width direction of a vehicle of a rack housing 6 where an input shaft 1 and a pinion 2 is supported free of rotation, while a cylindrical steering rod 11 is inserted into those of rack housing 6 and cylinder tube 9, and a rack bar 4 is inserted into the steering rod 11 as well. Then, a notch 5 is installed almost in the center in the vehicle width direction of the steering rod 11 so as to have a rack 3 exposed to the outside of the steering rod 11, and the pinion 2 is engaged with the rack 3 exposed by this notch. In addition, on an outer circumference of the steering rod 11, there are provided pistons 16 at both sides of the rack housing 6, and these pistons 16 is installed in the cylinder tube 9 free of slide motion, constituting a power cylinder in this way.

Description

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

(Prior Art) FIGS. 6 and 7 show a conventional rack and pinion type hydraulic power steering device, in which a helical pinion 101 is interlocked with a steering handle and meshes with this pinion 101. A rack bar 103 on which a helical rack 102 is formed, a rack housing 104 that covers the pinion 101 and the rack 102, and a rack housing 104 that is integrated with the rack housing 104 and that includes the rack bar 1.
03 and a cylinder tube 105 that is fitted onto the outside of the cylinder tube 105.

A steering wheel (not shown) is connected to both ends of the rack bar 103 via a ball joint 106, a tie rod 107, a knuckle arm, etc., and the rack bar 103 is rotated by a pinion 1o1.
03 in the rack axis direction, the steering wheels are steered.

Further, between the inner and outer peripheries of the rack bar 103 and the cylinder tube 105, an oil chamber 110 is formed which is made oil-tight by a pair of seal members 108 and 109.

A piston 111 is provided on the outer periphery of the rack bar 103, and piping 111 is provided on one side and the other side in the longitudinal direction of the oil chamber 110 partitioned by the piston 111.
12 and 112, pressure oil is supplied according to the steering direction, so that an assisting force for steering operation is applied to the rack bar 103.

The rack bar 103 is supported by the inner peripheral surface of the cylinder tube 105 via the bushing 113 on one side in the axial direction, and is supported by the rack housing 104 via a support yoke 114 built in the rack housing 104.
is supported by That is, the rack bar 103 is supported at two points via the bushing 113 and the support yoke 114 (the rack bar 103 is supported at two points via the bushing 113 and the support yoke 114).
8.109 and the inner peripheral surface of the cylinder tube 105 via the seal member 116 on the outer periphery of the piston 111, but the seal member is easily deformed and therefore does not serve as a support point).

The support yoke 114 is connected to the rack housing 104.
The position of the rack 102 and the pinion 101 can be changed in the direction of adjusting the engagement between the rack 102 and the pinion 101 (in the left-right direction in FIG. 6) by moving the plug 115 screwed into the rack 102 and the pinion 101 back and forth in the screwing direction. As a result, the rack bar 1
By changing the position of 03 in the direction of adjusting the meshing between the rack 102 and the pinion 101, a smooth meshing state can be obtained.

Further, the support yoke 114 is biased by the compression spring 117 and comes into contact with the rack bar 103, thereby allowing the rack bar 103 to move in the meshing adjustment direction due to manufacturing errors in gear cutting, etc., thereby achieving a smooth meshing state. It is considered a thing.

(Problems to be Solved by the Invention) When the steering device with the above configuration is used in a large vehicle, or when the slope of either the rack bar 103 or the tie rod 107 becomes large due to the vehicle layout, it is necessary to Since the steering reaction force acting on the rack bar 103 increases, countermeasures are required to reduce deformation and improve the strength of the rack bar 103.

To deal with this, the diameter of the rack bar 103 may be increased, or the rack bar 103 may be
It is conceivable to increase the number of support points by supporting the inner circumferential surface of the cylinder tube 105 via a plurality of bushes.

However, when the diameter of the rack bar 103 is increased, the distance between the shafts of the rack 102 and the pinion 101 increases, the effective length of the teeth of the pinion 101 increases, and the entire device becomes unnecessarily large. be.

Furthermore, if the rack bar 103 is supported at multiple positions on the inner circumferential surface of the cylinder tube 105, the rack bar 103 becomes immovable in the meshing adjustment direction, making it impossible to adjust the meshing between the rack 102 and the pinion 101 via the support yoke 114. 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 that can solve the problems of the prior art described above, and is characterized by: a rack bar formed with a rack that meshes with the pinion, and a steering rod that is interlocked and connected to a steering wheel, the steering rod having a cylindrical shape, and the rack bar being attached to the steering rod. The rack bar is inserted and has a cutout for exposing the rack, and the rack bar is connected to the steering rod so as to move along with the rack in the axial direction of the rack.

Furthermore, it is preferable that the rack bar is connected to the steering rod so that its position can be changed in the direction of adjusting the engagement of the rack with the pinion.

According to the configuration of the present invention, by transmitting the steering input from the pinion, the rack bar and the steering rod move together so as to steer the steering wheels.

In addition, reducing the deformation of the steering rod and rack bar due to steering reaction force and improving their strength can be achieved by increasing the diameter of the steering rod or increasing the number of support points for the steering rod. There is no need to increase it.

In addition, even if the position of the rack cannot be changed in the direction of adjusting the meshing of the rack with the pinion due to an increase in the number of support points for the steering rod, the rack bar or the steering rod should be connected to the rack bar or the steering rod so that the position can be changed in the direction of adjusting the meshing of the rack with the pinion. This makes it possible to adjust the engagement between the rack and pinion.

(Example) Hereinafter, the present invention will be described in detail with reference to the drawings.

Figures 1 to 4 show a rack and pinion hydraulic power steering system for an automobile, with an input shaft attached to a handle (not shown).
The rack bar 4 includes a helical pinion 2 connected via a helical pinion 2, and a rack bar 4 formed with a helical rack 3 that meshes with the pinion 2.

The input shaft 1 and pinion 2 are rotatably supported within a rack housing 6 and are connected via a torsion bar 7 (in FIG. 1, the left and right sides of the rack housing 6 refer to left and right sides. (Due to the symmetrical structure, the part on the right side is omitted from the illustration.)

Flanges 8 are formed on both sides of the rack housing 6 in the vehicle width direction, and a cylindrical cylinder tube 9 is connected via the flanges 8 with bolts IO to be integrated. The cylinder tube 9 is fixed to a 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.

On the outer end side of the steering rod 11 in the vehicle width direction,
A notch 5 is provided so that the rack 3 is exposed to the outside of the steering rod 11, so that the exposed rack 3 meshes with the pinion 2.

The rack bar 4 and the steering rod 11 are coupled so as to move together in the rack axis direction, and
A steering wheel (not shown) is operatively connected to each end of the steering rod 11 via a ball joint 12. As a result, pinion 2
The rotation of the rack bar 4 and steering rod 11
and move together in the direction of the rack axis, and the steering wheels are steered.

Further, bushings 13 are attached to the outer ends of the cylinder tubes 9 in the vehicle width direction, and the steering rod 11 or the seal member 14 is attached to the bushings 13.
15, and is slidably inserted in the rack axis direction.

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

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

By supplying pressure oil to one of the pair of oil chambers 18 according to the steering direction, an assist force for steering operation is applied to the steering rod 11 via the piston 16.

Further, in order to adjust the engagement between the pinion 2 and the rack 3, the rack bar 4 can be adjusted in position with respect to the pinion 2 in the left-right direction in FIG.

That is, circumferential grooves 19 are formed on the outer periphery of both ends of the rack bar 4 in the axial direction.
A ring 20 is fitted, and a ring body 21 is fitted onto the outside via this O-ring 20. In addition, the ring body 21
An O-ring 2, which is an elastic body, is placed in a circumferential groove 22 formed on the outer periphery of the
3 is fitted, and the ring body 2 is inserted through this O ring 23.
1 is inserted into the steering rod 11.

As a result, the rack bar 4 is supported by the steering rod 11 via the O-rings 20.23, and the O-rings 20 and 23 are supported by the steering rod 11.
Due to the elastic deformation of 0.23, the position of the pinion 2 and the rack 3 can be changed in the mesh adjustment direction.

Furthermore, the rack bar 4 and the steering rod 11 are capable of relative rotation around the rack axis.

That is, the rack bar 4 is slidable relative to the steering rod 11 around the rack axis via the O-rings 20.23 and the ring body 21.

As a result, based on the steering reaction force, the steering lorado 11
The force that would try to rotate the rack par 4 around the rack axis is prevented from being transmitted to the rack par 4.

Therefore, pinion 2 and rack 3 are helical,
If the meshing portion generates a force that attempts to rotate the rack par 4 around the rack axis, the pinion 2 and the rack 3 can be smoothly anastomosed even if a large steering reaction force is applied. can be maintained.

A support yoke 24 is attached to the rack housing 6 as a support member for the rack par 4.

This support yoke 24 has an outer circumference or a cylindrical surface, one end side is in contact with the outer circumferential surface of the rack par 4, and the other end side is the plug 25.
is inserted into. The plug 25 is screwed into the rack housing 6 via a male thread on the outer periphery and is fixed with a lock nut 26. Further, a compression spring 27 that engages with the support yoke 24 and the plug 25 is built into the support yoke 24 and urges the support yoke 24 in the direction of contact with the rack par 4.

Then, as the plug 25 moves forward and backward in the screwing direction into the rack housing 6, the support yoke 24 is moved toward the pinion 2.
The position can be changed and adjusted in the direction of adjusting the engagement between the rack 3 and the rack 3.

By adjusting the position of the support yoke 24, the position of the rack par 4 is changed in the meshing adjustment direction, and the meshing between the pinion 2 and the rack 3 is adjusted to obtain a smooth meshing state.

In addition, since the support yoke 24 is biased in the direction of contact with the rack par 4 via the compression spring 27, movement of the rack par 4 in the meshing adjustment direction due to manufacturing errors in gear cutting is allowed, and smooth anastomosis is achieved. It is said to obtain the state.

Since the support yoke 24 passes through the steering rod 11, a through hole 28 for this purpose is formed in the steering rod 11. This through hole 28
is an elongated hole extending 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 axis of the through hole 28 is made approximately equal to the outer peripheral diameter of the support yoke 24. As a result, rotation of the steering rod 11 relative to the pinion 2 about the rack axis is restricted by the engagement of the outer periphery of the support yoke 24 with the inner periphery of the through hole 28 .

In this way, the steering rod 11 is prevented from rotating about the rack axis relative to the pinion 2, thereby preventing the steering rod 11 from interfering with the pinion 2.

Note that the steering rod 11 has a 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.
It is also possible to restrict rotation of the pinion 2 about the rack axis.

As described above, the rack par 4 and the steering rod 11 are connected so that they move together in the rack axis direction. Therefore, a stopper is provided to restrict relative movement of the rack par 4 in the rack axis direction with respect to the steering rod 11.

In this embodiment, the ball joints 12 at both ends of the steering rod 11 also serve as stoppers.

That is, the ball joint 12 includes a ball holding cylinder 29, a ball 30 rotatably held within the hole holding cylinder 29, a block 3I that supports this ball 30 via a seat 33, and a ball 30 and a block 31. A cap 32 is screwed onto the ball holding tube 29 to prevent it from coming off from the hole holding tube 29, and a compression spring 34 built into the cap 32 presses and biases the block 31 against the ball 30.
It is equipped with Further, a connecting shaft 35 is connected and fixed to the ball 30.

Each ball joint 12 is screwed into a female thread 37 formed on the inner periphery of both ends of the steering rod 1 via a male thread 36 formed on the outer periphery of the ball holding cylinder 29. This ball joint 12 comes into contact with each end face of the rack par 4, respectively.

As a result, relative movement of the rack par 4 with respect to the steering rod 11 in the rack axis direction is regulated by the ball joint 12 which also serves as a stopper, and the rack par 4 and the steering rod II are moved in the rack axis direction, that is, the direction in which the steering wheels are steered. It is assumed that they will travel together.

Also, by restricting the relative movement of the rack par 4 with respect to the steering rod 11 in the rack axis direction,
This prevents the steering wheel from becoming stiff when operating the steering wheel.

In this way, this can be done by attaching the ball joint 12 which also serves as a stopper, or by screwing into the female threaded portions 37 formed on the inner periphery of both ends of the steering rod 11, taking advantage of the fact that the steering rod ll is cylindrical. By doing so, the structure is simplified.

The ring body 21 is sandwiched between the ball joint 12 and the inner circumferential stepped portion 39 of the steering rod 11, so that relative movement in the rack axis direction with respect to the rack par 4 is restricted.

Further, the male threaded portion 36 of each ball holding cylinder 29 is provided with a lock nut 38 that contacts the end surface of the steering rod 11.
are screwed together to prevent the ball holding cylinder 29 from loosening. The lock nut 38 is integrally formed with a regulating portion 40 for preventing overstroke that projects radially outward. The restriction portion 40 comes into contact with the bush 13, thereby restricting movement of the steering rod 11 in the rack axis direction more than necessary.

Further, a connecting block 42 is screwed onto the connecting shaft 35 via a lock nut 41, and a steering wheel is connected to this connecting block 42 via a knuckle arm or the like. Thereby, by adjusting the amount by which the connecting block 42 is screwed into the connecting shaft 35, it is possible to adjust the toe-in of the vehicle.

Pressure oil is supplied to the oil chamber 18 through a rotary valve 4 fitted externally on the input shaft l and connected to the pinion 2.
3.

That is, pressure oil supplied from a tank (not shown) via a pump reaches an oil path between the inner and outer peripheries of the rotary valve 43 and the input shaft l from the supply hole 44 formed in the rack housing 6. A connection hole 4 that communicates from this oil passage to the right steering oil chamber 18
5 and a connection hole 46 connected to the left steering oil chamber 18 are formed in the rack housing 6. The rotary valve 43 is supposed to rotate together with the pinion 2,
According to 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 4
The oil passage between the inner and outer circumferences of the input shaft 1 and the input shaft 1 is connected to the connection hole 45 or the connection hole 46, and one oil chamber 1 is connected to the other oil chamber 1 according to the steering direction.
8 is supplied with pressure oil, and oil is returned from the other oil chamber 18 to the tank through a discharge hole 47 formed in the rack housing 6.

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

A bellows cover 50 made of an elastic material is provided to cover the steering rod 11 and ball joint 12 that protrude from both ends of the cylinder tube 9, and is fixed to the connecting shaft 35, the ball holding cylinder 29, and the outer periphery of the cylinder tube 9. It is fixed with a ring etc.

According to the above steering device, the steering rod 1
1 is supported at three places via the support yoke 24 and two bushings 13, compared to the conventional case where it was supported at two places via the support yoke and one bushing. The deflection of the steering rod 11 and the rack par 4 due to the steering reaction force is reduced, making it suitable for use in large vehicles with large steering reaction forces.

In addition, in order to improve the strength and reduce deformation against steering reaction forces, it is sufficient to increase the diameter of the steering rod 11, and there is no need to increase the rack par 4. The effective length of can be kept unchanged,
The entire device does not become unnecessarily large.

In addition, even if the steering rod 11 cannot be repositioned in the direction of meshing adjustment between the pinion 2 and rack 3 due to the increase in the number of support points for the steering rod 11, the rack par 4 can be repositioned in the direction of meshing adjustment, thereby ensuring smooth operation. A state of engagement can be obtained.

Note that the present invention is not limited to the above embodiments.

For example, in the above embodiment, the ball joint 12 also serves as a stopper for regulating the relative movement of the rack bar 4 and the steering rod 11 in the rack axis direction, but as shown in FIG. Alternatively, a stopper 60 may be provided separately.

That is, each stopper 60 has a male threaded part 61 formed on its outer periphery, is screwed into a female threaded part 37 formed on the inner periphery of both ends of the steering rod 11, and comes in contact with both ends of the rack bar 4, thereby connecting the rack bar 4 and the steering rod. 11 in the rack axis direction. Note that a tool retaining hole 62 is formed in the stopper 60.

Further, in the embodiment shown in FIG. 5, a ring portion 63 is integrally formed on the stopper 60 instead of the ring body 21 in the above embodiment, and a circumferential groove 22 is formed in this ring portion 63.
When the ring 23 is fitted, it performs the same function as the ring body 21.

Furthermore, in the embodiment described above, it was possible to adjust the toe-in of the vehicle by adjusting the screwing amount of the connection block 42 with respect to the connection shaft 35, but in this embodiment, the ball joint 1
Since it is not necessary to perform a stopper function, toe-in adjustment is performed by adjusting the screwing amount of the ball joint 12 into the steering rod 11. Therefore, since the connecting shaft 35 and the connecting block 42 do not need to be separate bodies, they are integrally molded and are miniaturized, making them suitable for cases where space is limited.

The other configurations are similar to those of the above embodiment, and the same parts are designated by the same reference numerals.

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

Further, the number of support points for the steering rod 11 may be increased or decreased compared to the above embodiment.

The present invention can also be applied to hydraulic power steering devices, manual steering devices, and electric power steering devices.

(Effects of the Invention) According to the present invention, since the steering rod is cylindrical and the rack bar is inserted into the steering rod, deformation due to steering reaction force can be reduced and strength can be improved due to the diameter of the steering rod. This can be done by increasing the diameter of the rack bar and increasing the number of support points, etc., and there is no need to increase the diameter of the rack bar.
This can prevent the entire device from becoming unnecessarily large.

In addition, since the rack bar is connected to the steering rod so that its position can be changed in the direction of adjusting the meshing of the rack with respect to the pinion, even if the steering rod cannot be changed in its position in the direction of adjusting the meshing of the rack and the pinion, it is possible to adjust the meshing of the rack and pinion. 1 to 5 relate to embodiments of the present invention, FIG. 1 is a front sectional view of the steering device, FIG. 2 is a side sectional view of the steering device, and FIG. 3 is a side sectional view of the steering device. Fig. 4 is a rear view of the main parts of the steering device, Fig. 5 is a front sectional view of the main parts of the steering device according to a different embodiment, and Fig. 6 is a 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.

Patent applicant: Koyo Seiko Co., Ltd. Agent: Susumu Udomoto, and 1 other person

Claims (2)

[Claims] (1) A pinion for transmitting a steering operation input, a rack bar formed with a rack that meshes with the pinion, and a steering rod interlocked with a steering wheel, the steering rod having a cylindrical shape, The steering rod is characterized in that the rack bar is inserted therein and a notch is formed to expose the rack, and the rack bar is connected to the steering rod so as to move along with the rack in the axial direction of the rack. Rack and pinion steering device. (2) The rack and pinion type steering device according to claim (1), wherein the rack bar is connected to the steering rod so that its position can be changed in the direction of adjusting the engagement of the rack with the pinion.