JPH04317862A - Rack pinion type steering device - Google Patents

Abstract

PURPOSE:To prevent the moment by the force acting on a steering wheel from being transmitted to a rack by mounting a ball joint on one end of the rack, and mounting a connecting link with the steering wheel on the one end of the rack through the ball joint. CONSTITUTION:A pinion 3 and a rack 4 geared with the pinion 3 are provided. The pinion 3 is connected to an input shaft 10 through a torsion bar inserted through a rotary valve 30, and the rack 4 is supported in a housing 5 through a lateral pair of bushes 12, 13. Both ends 4a, 4b of the rack 4 are protruded from both ends of the housing 5, and a ball joint 6 is mounted on the right end part 4a. A connecting link to be connected to a tie rod for connecting right and left steering wheels to each other is mounted on the connecting screw 17 of the ball joint 6. Thus, the moment by the force acting on the steering wheels is prevented from being transmitted to the rack 4, and a smooth gearing between the pinion 3 and the rack 4 is ensured.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called single-end type rack and pinion steering device.

0002

[Prior Art] A rack-and-pinion steering wheel that includes a pinion that rotates in response to a steering input, a rack that meshes with the pinion, and a housing that covers the rack, and a link for connecting the steering wheel to the rack is attached. The device is widely used.

[0003] As such a rack and pinion type steering device, as disclosed in Japanese Utility Model Application Publication No. 60-73665, an opening is provided on the outer periphery of the housing, and a rack and a connecting link are connected through this opening. There is a so-called center take-off type.

Furthermore, as disclosed in Japanese Patent Application Laid-Open No. 116636/1983, there is a device in which a rack is protruded from both ends of the housing, and connecting links are attached to each end of the rack.

However, each of the rack and pinion type steering devices described above has a complicated structure and the axial dimension of the rack is long, so that they are not suitable for vehicles where the space for installing the steering device is limited.

[0006] Therefore, a single-end type rack and pinion type steering device 101 as shown in FIG. 8 is used. The steering device 101 includes a pinion 102 that rotates in response to a steering input, a rack 103 that meshes with the pinion 102, and a housing 104 that covers the rack 103. One end 103a of the rack 103 protrudes from one end of the housing 104, and links 105 and 106 for connection to steering wheels W are attached to the one end 103a of the rack 103 via brackets 107 and bolts 108. Also, rack 10
A piston 109 is attached to the piston 10.
A pair of oil chambers 110 and 111 partitioned by 9 are formed inside the housing 104. This oil chamber 110,
By supplying pressure oil to the rack 111, an auxiliary force for steering operation is applied to the rack 103.

[0007]

[Problems to be Solved by the Invention] The steering device 101 shown in FIG. 8 is of a type in which links for connecting steering wheels are attached to both ends of the rack, or a center take-off type steering device. The structure is simpler than that, and the axial length of the rack is shorter, which is advantageous in terms of space.

However, the steering device 10 shown in FIG.
1, one end 103a of the rack 103 and the link 1
05 are connected by bolts 108, the moment generated by the force acting on the steering wheel W from the road surface acts on the rack 103, causing a problem that the pinion 102 and the rack 103 do not mesh smoothly. .

Furthermore, a steering device 101 shown in FIG.
In this case, the piston 109 in one oil chamber 110
The pressure receiving area of the piston 10 in the other oil chamber 111 is
It is larger than the pressure receiving area of 9. This is because the rack 103 is located only in the other oil chamber 111, so the pressure receiving area of the piston 109 in one oil chamber 110 is
The piston 1 in the other oil chamber 111 has a cross-sectional area of 03.
This is because the pressure receiving area is larger than that of 09.

[0010] Then, if the oil pressure acting on the piston 109 in one oil chamber 110 is equal to the oil pressure acting on the piston 109 in the other oil chamber 111, the steering wheel operating force required for right steering and the steering force required for left steering are equal. A problem arises in that the steering force is different and the feeling of the operator's operation is different depending on the steering direction. Therefore, as a valve used to supply pressure oil to the oil chambers 110 and 111, it is necessary to use a special valve that makes the oil pressure acting on one oil chamber 110 larger than the oil pressure acting on the other oil chamber 111. there were. However, the use of such a special valve has been a factor in increasing costs.

SUMMARY OF THE INVENTION 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.

0012

[Means for Solving the Problems] The present invention is characterized by comprising a pinion that rotates in response to a steering operation input, a rack that meshes with this pinion, and a housing that covers this rack, and that protrudes from one end of the housing. In a rack and pinion type steering device in which a link for connecting to the steering wheel is attached to only one end of the rack, a ball joint is attached to one end of the rack, and the connecting link connects to one end of the rack via this ball joint. Located at the point where it is mounted. Further, when the present invention is applied to a hydraulic power steering device, a piston is provided in the rack, a pair of oil chambers partitioned by the piston are formed inside the housing, and pressure oil is supplied to the oil chambers. Preferably, both oil chambers are penetrated by the rack so that an assisting force for steering operation is applied to the rack, and the pressure receiving area of the piston in each oil chamber is equal.

[0013]

[Function] According to the structure of the present invention, a ball joint is attached to one end of the rack, and a link for connecting the steering wheel to the rack is attached to one end of the rack through this ball joint, so that the steering wheel is connected to the road surface. The ball joint prevents moments caused by forces acting from being transmitted from the link to the rack.

Further, when the present invention is applied to a hydraulic power steering device, by making the rack pass through an oil chamber partitioned by a piston, the pressure receiving area of the piston in each oil chamber can be equalized. Thereby, the steering operation feeling for the operator can be made the same regardless of the steering direction, without making the oil pressure in each oil chamber different.

[0015]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

A rack and pinion type hydraulic power steering device 1 shown in FIG. 5 is connected to a steering handle 2 and steering wheels W. This steering device 1
As shown in FIGS. 1 and 2, a pinion 3 connected to the handle 2, a rack 4 meshing with the pinion 3,
A housing 5 that covers the rack 4 is provided.

As shown in FIG. 2, the pinion 3 is connected to an input shaft 10 via a torsion bar 11, and the input shaft is connected to the handle 2. Thereby, rotation of the handle 2 is transmitted from the input shaft 10 to the pinion 3 via the torsion bar 11.

As shown in FIG. 1, the rack 4 that engages with the pinion 3 is supported on the inner peripheral surface of the housing 5 via a pair of left and right bushes 12 and 13. Each end 4a, 4b of the rack 4 protrudes from both ends of the housing 5, and a ball joint 6 is attached to one end 4a of the rack 4 protruding from the left end of the housing 5 in FIG.

The ball joint 6 includes a ball housing 15, a ball 16 held by the ball housing 15, and a connecting screw 1 integrated with the ball 16.
7. The axial direction of the connecting screw 17 is substantially perpendicular to the axis of the rack 4 when the vehicle moves straight. Also,
A male screw 15a is integrally provided on the ball housing 15, and this male screw 15a is screwed into one end 4a of the rack 4. Note that a lock nut 18 is screwed onto the male thread 15a.

As shown in FIG. 5, the link 7 for connecting to the steering wheel W is attached to the connecting screw 17 of the ball joint 6 via a mounting nut 19. That is, the connecting link 7 is fitted into the connecting screw 17 and is prevented from coming off by the nut 19 screwed onto the connecting screw 17. The connecting link 7 is connected to a tie rod 20 that connects the left and right steering wheels W.

[0021] As a result, when the handle 2 is rotated,
The rotation causes the pinion 3 to rotate, and the rotation of the pinion 3 causes the rack 4 to move in the vehicle width direction, and the movement of the rack 4 in the vehicle width direction causes the ball joint 6, link 7,
The signal is transmitted to the steering wheel W via the tie rod 20, and the vehicle is steered.

As shown in FIG. 1, a piston 8 is provided on the rack 4 between the pair of left and right bushes 12 and 13. Seal members 25, 26, 27, and 28 for sealing between the outer peripheral surface of the rack 4 and the inner peripheral surface of the housing 5 are attached to the bushes 12, 13 and the piston 8. As a result, between both bushes 12 and 13,
A pair of left and right oil chambers 9 and 10 partitioned by a piston 8
is formed.

As shown in FIG. 2, a rotary valve 30 is provided on the outer periphery of the input shaft 10 in order to supply pressurized oil to each of the oil chambers 9 and 10 in accordance with the steering direction. This rotary valve 30 is a known one, and includes a valve housing 31 integrated with a housing 5, and the input shaft 10.
and a valve member 32 located between the valve housing 31 and the valve housing 31. The valve member 32 is configured to rotate together with the pinion 3. The valve housing 31 also has an inlet port 33 that is connected to a pump for supplying pressure oil (not shown), an outlet port 34 that is connected to a tank (not shown), and an oil chamber 9 that is connected to one of the oil chambers 9. A connection port 35 is provided, and a connection port 36 is connected to the other oil chamber 10 via piping.

The rotation of the input shaft 10 due to the operation of the handle 2 is transmitted to the pinion 3 via the torsion bar 11.
The valve member 32 rotates together with the pinion 3. At this time, when the torsion bar 11 is twisted by the torque based on the reaction force from the road surface acting on the steering wheel W, the input shaft 10 and the valve member 32 rotate relative to each other. As a result, the oil passages communicating between the ports 33, 34, 35, and 36 formed between the input shaft 10 and the valve member 32 are opened and closed, and each oil chamber is opened or closed according to the steering direction and the steering reaction force. Pressure oil is supplied to 9 and 10. As a result, hydraulic pressure acts on the piston 8 to provide auxiliary force for steering operation.

At this time, the piston 8 in one oil chamber 9
Both oil chambers 9 and 10 are connected to the rack 4 so that the pressure receiving area of the piston 8 in the other oil chamber 10 is equal to the pressure receiving area of the piston 8 in the other oil chamber 10.
penetrated by. That is, the pressure-receiving area of the piston 8 in each oil chamber 9, 10 is the area obtained by subtracting the cross-sectional area of the cylindrical rack 4 from the cross-sectional area of the cylindrical oil chambers 9, 10.

[0026]Thereby, in order to equalize the operator's steering operation feeling depending on the steering direction, it is not necessary to vary the magnitude of the hydraulic pressure acting on the piston 8 depending on the steering direction. , there is no need to use a special rotary valve 30.

Note that the support yoke 37 is attached to the housing 2.
A compression spring 38 is inserted, and a plug 39 is screwed together. The support yoke 37 presses the rack 4 against the pinion 3 by the elastic force of the spring 38. and,
By adjusting the screwing amount of the plug 39, the elastic force of the spring 38 is adjusted, and the engagement between the rack 4 and the pinion 3 is adjusted.

Furthermore, in order to attach the housing 5 to the vehicle body, attachment arms 5b and 5c are integrally extended from the housing 5, as shown in FIG. Cylindrical anti-vibration rubbers 40 and 41 are inserted into the mounting arms 5b and 5c, bushes 42 and 43 are inserted into the anti-vibration rubbers 40 and 41, and bolts (
(not shown), the housing 5 is fixed to the vehicle body.

In addition, for mounting the housing 5, FIG.
As shown in FIG. 2, a vibration isolating rubber 45 is fitted into the housing 5, and a bracket 46 is provided to cover the vibration isolating rubber 45.
A bolt inserted into the through hole 46a of this bracket 46 (
(not shown), the housing 5 is fixed to the vehicle body.

Further, each end 4a, 4b of the rack 4 protruding from each end of the housing 5 is provided with a telescopic bellows cover 50,
51 to prevent dust from entering the inside of the steering device. A through hole 52 is provided along the axial direction of the rack 4 in order to communicate the internal spaces of the bellows covers 50 and 51.
is formed, and one end of this through hole 52 is connected to the through hole 5 along the radial direction.
3 communicates with the internal space of one bellows cover 50,
The other end of the through hole 52 communicates with the inner and outer peripheries of the rack 4 and the housing 8, which communicate with the internal space of the other bellows cover 51, through a through hole 54 extending in the radial direction.

6 and 7 show a rack and pinion type steering device 1' according to a second embodiment of the present invention. The same parts as in the first embodiment are indicated by the same reference numerals, and differences will be explained.

In the second embodiment, a ball joint 6' attached to one end 4a of the rack 4 includes a ball housing 15', a ball 16' held by the ball housing 15', and a ball joint 6' integrally attached to the ball 16'. 17'. The ball housing 15
The ball joint 6' is attached to the one end 4a of the rack 4 by caulking the connecting fitting 60 between the ball joint 6' and the one end 4a of the rack 4. Further, the connecting member 17' is arranged to extend approximately along the axial direction of the rack when the vehicle moves straight. One end of each of a pair of connecting links 7' is attached to this connecting member 17', and the other end of each connecting link 7' is connected to a knuckle arm of a steering wheel W. In order to connect the connecting member 17' and the connecting link 7', the connecting member 1
A pair of through holes 61 and 62 are formed in 7', and this through hole 61
, 62, the bracket 65 is attached to the connecting member 17', and the connecting link 7' is attached to the bracket 65 with the bolts and nuts 66.
, 67.

According to the steering device 1, 1' having the above structure, the moment due to the force acting on the steering wheels W from the road surface is transmitted from the links 7, 7' to the rack 4 through the ball joints 6, 6. ' is prevented. This allows the rack 4 and pinion 3 to mesh smoothly.

[0034] Also, the piston 8 in each oil chamber 9, 10
Since the pressure receiving areas of the oil chambers 9 and 10 are equal, there is no need to use a special valve 30 for sending pressure oil to the oil chambers 9 and 10, and costs can be reduced.

Furthermore, since the internal spaces of the bellows covers 50 and 51 covering both ends 4a and 4b of the rack 4 are communicated with each other,
There is no problem in changing the volume of the internal space of the bellows covers 50, 51 due to movement of the rack 4. That is, since the air in the interior space of one of the bellows covers 50, 51 can flow into the interior space of the other when the rack 4 is moved, there is no problem in the expansion and contraction of both the bellows covers 50, 51.

[0036]

According to the present invention, in the single-end type rack and pinion type steering device, the link for connecting the steering wheel is attached to one end of the rack via a ball joint, so that the steering wheel is not affected. This prevents the moment caused by the force from being transmitted to the rack, and allows smooth engagement between the pinion and the rack.

Furthermore, when the present invention is applied to a hydraulic power steering device, both oil chambers partitioned by a piston are penetrated by a rack, so that the pressure receiving area of the piston provided in the rack is equalized in each oil chamber. Therefore, there is no need to use a special valve to make the steering feel the same regardless of the steering direction, and costs can be reduced.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a rack and pinion steering device according to a first embodiment of the present invention.

[Figure 2] Cross-sectional view taken along the line II-II in Figure 1

[Figure 3] Cross section taken along line III-III in Figure 1

[Figure 4] Cross-sectional view taken along the line IV-IV in Figure 1

[Fig. 5] Configuration explanatory diagram of the steering device

FIG. 6 is a sectional view of a rack and pinion steering device according to a second embodiment of the present invention.

FIG. 7 is an explanatory diagram of the configuration of a steering device according to a second embodiment of the present invention.

[Fig. 8] Partially cutaway view of a conventional steering device

[Explanation of symbols]

1 Rack and pinion steering device 3 Pinion 4 Rack 5 Housing 6 Ball joint 7 Connecting link 8 Piston 9 Oil chamber 10 Oil chamber W Steering wheel

Claims (2)

[Claims] Claim 1: A pinion that rotates in response to a steering operation input, a rack that meshes with this pinion, and a housing that covers this rack, and only one end of the rack that protrudes from one end of the housing is provided with a steering wheel. A rack and pinion type steering device to which a connecting link is attached, characterized in that a ball joint is attached to one end of the rack, and the connecting link is attached to one end of the rack via the ball joint. . Claim 2: The rack is provided with a piston, a pair of oil chambers partitioned by the piston are formed inside the housing, and by supplying pressurized oil to the oil chambers, an auxiliary force for steering operation is applied to the rack. 2. The rack and pinion type steering device according to claim 1, wherein both oil chambers are penetrated by a rack so that the pressure receiving area of the piston in each oil chamber is equal.