JP2791259B2 - Hydraulic steering system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic steering system for a vehicle.

[0002]

2. Description of the Related Art A conventional steering device has an input shaft connected to a steered wheel, an output screw shaft interlocked with the input shaft, and a rack portion meshed with a screw portion of the output screw shaft. And a tie rod that is connected to the steering wheel to steer the steering wheel. When the steering wheel is displaced, the steering wheel is rotated to rotate the input shaft connected thereto, and the input shaft is rotated. An output screw shaft that rotates with the shaft is rotated, and a tie rod that is connected to a steering wheel and steers the steering wheel is moved through a rack that meshes with a screw portion of the output screw shaft. By the way, in such a steering device, there is a problem that the rotation ratio between the input shaft and the output screw shaft is 1: 1, a large steering force is required, and the steering force is not smooth.

In order to solve such a problem, power steering devices have been used.
Typical examples include those shown in FIGS. This is such that the input shaft 1 and the output screw shaft 2 are interlocked via a control valve 50, and the control valve 50 is connected to a spool 51 connected to the input shaft 1 and the output screw shaft 2. A spool 52 and a sleeve 52 connected to each other.
Are housed in the valve body 53. A torsion bar 55 is housed inside the output screw shaft 2 and the spool 51, and is connected to them. The sleeve 52 and the spool 51 communicate with the inside and outside of the sleeve 52 and the spool 51, respectively.
And 70 are provided. The valve body 53 is provided with an inlet port 54 and an outlet port 56, and these ports 54,
The pump 57 and the tank 58 are connected to 56, respectively, and the pump 57 and the tank 58 are also connected. The valve body 53 is also provided with a pair of control ports 60 and 61. On the other hand, a piston 62 is slidably fitted in the middle of the cylinder 13 of the tie rod 5 to form left and right working chambers 71 and 72 on both sides. An operation port 6 that communicates with control ports 60 and 61 through pipes 48 and 49 to target positions of the operation chambers 71 and 72 with a piston 62 interposed therebetween.
3 and 64 are provided. Oil seals 66 and 67 are provided outside the operation ports 63 and 64, and an oil seal 68 is also provided on the piston 62.

FIGS. 11 and 12 show a non-steering operation and the input shaft 1
Shows the operating state of the control valve 50 at the time of neutralization. In this case, the pressure oil sent from the pump 57 flows into the valve body 53 from the inlet port 54 and the sleeve 52
And the outlet port 56 through the communication passages 69 and 70 of the spool 51.
From the tank 58. At this time, the communication passages 73 and 74 of the sleeve 52 to the control ports 60 and 61 are in communication, but since the pressure is the same for both, no oil flows to the working chambers 71 and 72. FIGS. 13 and 14 show the operating state of the rotary valve 50 during the steering operation and the rotation of the input shaft 1. In this case, the rotation of the input shaft 1 is controlled by the output shaft 2 via the spool 51 and the torsion bar 55. The screw 3 rotates and the tie rod 5 moves through the rack 4 to displace the steered wheels. At that time, the reaction force of the steered wheels is transmitted to the torsion bar 55 via the rack portion 4 of the tie rod 5 and the output screw shaft 2 and is twisted, causing a displacement difference in the control valve 50, and the spool 51 is attached to the sleeve 52. On the other hand, relative displacement shown as A in FIG. The pressure oil sent from the pump 57 due to this relative displacement is
After flowing into the valve body 53 from the valve body 54, the working port passes through the communication passages 69 and 73 of the sleeve 52 and the control port 61.
Flows into the working chamber 71 and flows into the other working chamber.
It flows out of 72 and is discharged from the outlet port 56 to the tank 58 through the communication path 74 of the sleeve 52 and the communication path 70 of the spool 51 via the operation port 64 and the control port 60. When the rotation direction is opposite, the direction is different only, and the other is the same. The piston 62 is moved toward the other working chamber 72 or 71 by the flow of these oils, and the tie rod 5 is also moved, thereby displacing the steered wheels to perform desired steering.

[0005]

By the way, in such a hydraulic steering apparatus, when the rotary valve 50 is operated at the time of the steering operation and the rotation of the input shaft 1, the pressure oil flows from the inlet port 54 to the valve body 53. Into the control port 60 or through the communication passage 69, 73 or 74 of the sleeve 52.
Flow to the working port 63 or 64 via 61, one working chamber 71
Or 72, while flowing out of the other working chamber 72 or 71 and moving the tie rod 5 by moving the piston 62 to the other working chamber 72 or 71 side, provided in the working chambers 72 and 71. The outer surface of the tie rod 5 slides on the oil seals 66 and 67, and the oil seal 68 of the piston 62
Sliding on the inner peripheral surface of the wheel, and the friction generated at this time worsens the steering feeling, and if the sliding resistance is reduced to improve this, the oil pressure will be insufficient and oil leakage will occur. There is also a cylinder 13 in which the piston 62 is arranged, and the cylinder 13 and the control valve
There is also a problem that the piping is required to be provided with pipes 48 and 49 connecting the 50 and 50, which complicates the structure and increases the cost.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the conventional hydraulic steering apparatus, to provide a good steering feeling at the time of steering, to maintain sufficient hydraulic pressure, and to cause oil leakage. An object of the present invention is to provide an inexpensive hydraulic steering device having a simple structure and a simple structure.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides an input shaft 1 connected to a handle and an output screw shaft interlocked with the input shaft 1. 2 and a tie rod 5 having a rack portion 4 meshing with the screw portion 3 of the output screw shaft 2 and being connected to a steering wheel to steer the steering wheel. The torque generator 10 is connected to the output screw shaft 2 via a torque generator 10. The torque generator 10 is connected to the housing 6 having the inlet port 7 and the outlet port 8, the internal tooth member 21, and the internal tooth member 21. An amplifying section 19 having an external tooth member 22 that rotates and revolves, and a switching valve 9 that is operated by the input shaft 1 and controls the flow of fluid between each port and the amplifying section 19; Is operated by the power of the amplification unit 19 It is assumed that. According to a second aspect of the present invention, in the first aspect, the internal teeth member 21 is constituted by a ring member 24 and a roller 28 which is slidably fitted in a semicircular recess 25 provided in the ring member 24.

[0008]

In the present invention as described above, the invention according to claim 1 is characterized in that when the steering wheel is rotated by the operator during the rotation, the input shaft 1 coupled thereto is rotated, and the input shaft 1 of the torque generator 10 is turned on. The fluid flowing into the housing 6 has an amount proportional to the amount of rotation of the input shaft 1 and is switched to the switching valve 9.
And flows into the amplifying unit 19, flows into a pressure chamber formed by the internal tooth member 21 and the external tooth member 22 of the amplifier unit 19, and generates a large torque generated in the external tooth member 22 by the pressure oil on the second drive shaft 27. To the output screw shaft 2 through which the screw portion 3 is rotated, and the tie rod 5 is moved through the rack portion 4 meshing with the screw portion 3 to rotate the steered wheels. The invention according to claim 2 is an internal tooth member
When the external tooth member 22 rotates and revolves in the inside 21, the roller 28 constituting the internal tooth member 21 is contacted with the teeth of the external tooth member 22 to form a semicircular recess 25 provided in the ring member 24. , And comes into rolling contact with the teeth of the external tooth member 22, thereby reducing the frictional resistance and the force required to rotate the input shaft 1.

[0009]

1 to 6 show an input shaft 1 connected to a handle (not shown). The input shaft 1 is connected to an output screw shaft 2 via a torque generator 10. The screw portion 3 of the output screw shaft 2 is connected to a steering wheel (not shown) and meshes with a rack portion 4 provided on a tie rod 5 for steering the same. The tie rod 5 is attached to the vehicle body. It is stored in the cylinder 13. The torque generator 10 is similar to the hydraulic actuator described in Japanese Patent Application Laid-Open No. 4-25773 filed earlier by the present applicant, and has a housing 6.
Are provided with an inlet port 7 and an outlet port 8, and a switching valve 9 is rotatably disposed in the center hole.
Is a rotatable spool 11 and a sleeve 12 cooperating therewith
And the spool 11 is formed at the inner end of the input shaft 1. 14 is a centering spring with both ends fitted in through holes provided in the spool 11 and the sleeve 12, and 16 is a spool with both ends
After passing through the through hole of 11 in the circumferential direction movably, the sleeve 12
A stopper pin 17 supported by the through hole indicates a first drive shaft. A forked portion is provided at one end of the first drive shaft 17, through which a stopper pin 16 penetrates, and a splined head 18 is provided at the other end. Reference numeral 19 denotes an amplifying unit, and the amplifying unit 19 has an internal tooth member 21 and one tooth less than that which is eccentrically provided in the internal tooth member 21 and meshes with the teeth of the internal tooth member 21. It has an external tooth member 22 that performs rotation and revolution, and a spline 23 is provided in a center hole of the external tooth member 22,
The spline of the head 18 of the first drive shaft 17 is engaged with the spline 23. A spline 26 is provided inside the output screw shaft 2, and a second drive shaft 27 having a splined head engaging with both splines 23, 26 is provided at both ends.

At the time of the non-steering operation shown in FIGS. 2 to 4 and the input shaft 1 is in the neutral position, the pressure oil flowing into the inlet port 7 from a hydraulic source (not shown) enters the first annular groove 32 of the housing 6, Six first through holes 33 provided at equal intervals in the sleeve 12 flow into the second annular groove 34 of the spool 11, and then six axially extending at equal intervals from the second annular groove 34 Into the first communication groove 35, into the twelve second through holes 36 provided at equal intervals in the sleeve 12, and into the six second communication grooves 37 extending in the axial direction of the spool 11. Then, the second communication groove 37 flows into the third annular groove 38 of the spool 11 with which the second communication groove 37 communicates, and the sleeve 12 is provided with an evenly spaced 6
Each of the third through holes 39 enters the fourth annular groove 40 of the housing 6 and is discharged from the outlet port 8. At this time, the third communication hole 42 to the amplifying section 19 provided in the housing 6 communicates with one of the second through holes 36, and the second through hole 36 is connected to the first communication groove 35 and the second communication groove 37. , The pressure becomes the same at all, so that no pressure oil flows into the amplifying section 19.

At the time of right rotation of the input shaft 1 for right steering operation shown in FIGS. 5 and 6, when the operator turns the steering wheel to the right, the centering spring 14 of the torque generator 10 bends and the spool 11 and the sleeve 12 are rotated. And the pressure oil flowing into the inlet port 7 enters the first annular groove 32 of the housing 6, and from the six first through holes 33 of the sleeve 12, the first Flows into the annular groove 34,
Then, the first annular groove 34 enters the six first communication grooves 35, enters the six second through holes 36 of the second through holes 36 of the sleeve 12, and three of the second through holes 36. It flows into the third communication hole 42 communicating with 36, flows into the amplification section 19, flows into the pressure chamber formed by the internal tooth member 21 and the external tooth member 22 of the amplification section 19, and the pressure oil makes the external tooth member 22 The generated large torque is transmitted to the output screw shaft 2 via the second drive shaft 27, and the screw portion 3 thereof is rotated to move the tie rod 5 rightward via the rack portion 4 meshing with the screw portion. After completing the work, the pressure oil in the amplification section 19 enters the three third communication holes 42, enters the second communication grooves 37 of the spool 11 from the second through holes 36, and then communicates with the second communication grooves 37. Flows into the third annular groove 38 of the spool 11
The sleeve 12 enters the fourth annular groove 40 of the housing 6 through the six third through holes 39 and is discharged from the outlet port 8. At this time, the rotation of the external tooth member 22 is controlled by the first drive shaft 17 and the stopper pin.
The rotation of the sleeve 12 via 16 causes an action to cancel the angular displacement between the spool 11 and the sleeve 12, and a small torque enough to deflect the centering spring 14 by a series of these operations produces an output screw shaft. 2, the tie rod 5 can be moved to the right with a large force. At the time of the left rotation, only the direction is different, and the other is the same, so that the description is omitted. Since the necessary steering torque is given by the hydraulic pressure of the torque generator 10 in this manner, the driver only needs a small operation torque to displace the centering spring 14.

A second embodiment of the present invention shown in FIGS.
Most of the components are the same as those in the first embodiment. Therefore, the same components are denoted by the same reference numerals and the description thereof will be omitted, and different components will be mainly described. This embodiment is different from the first embodiment in that the internal teeth member 21 is constituted by a ring member 24 and a roller 28 which is slidably fitted into a semicircular recess 25 provided in the ring member 24. When the external tooth member 22 rotates and revolves within the member 21, the rollers 28 constituting the internal tooth member 21
However, due to the contact with the teeth of the external tooth member 22, it rotates in the semicircular concave portion 25 provided in the ring member 24, and comes into rolling contact with the teeth of the external tooth member 22, thereby reducing the frictional resistance and inputting. The point is that the force required to rotate the shaft 1 is reduced, and there is no difference in other points.

[0013]

The present invention is as described above. The input shaft 1 coupled to the handle, the output screw shaft 2 interlocked with the input shaft 1, and the screw portion 3 of the output screw shaft 2 mesh with each other. In a hydraulic steering system having a rack portion 4 and being connected to a steering wheel and having a tie rod 5 for steering the same, the input shaft 1 is connected to an output screw shaft 2 via a torque generator 10, The torque generator 10 includes a housing 6 having an inlet port 7 and an outlet port 8, an internal tooth member 21,
And an amplifying unit 19 having an external tooth member 22 which is in the internal tooth member 21 and meshes with the internal tooth member to rotate and revolve, and the input shaft 1
The output screw shaft 2 is operated by the power of the amplification unit 19, so that the steering feeling at the time of steering is good. In addition, there is an effect that the hydraulic pressure is sufficient, no oil leakage occurs, the structure is simple, and the structure can be provided at low cost. According to a second aspect of the present invention, in the first aspect, the internal teeth member 21 is constituted by a ring member 24 and a roller 28 which is slidably fitted in a semicircular concave portion 25 provided in the ring member 24. When the external tooth member 22 rotates and revolves in the tooth member 21, the roller 28 rotates in the concave portion 25 of the ring member 24 by contact with the teeth of the external tooth member 22,
Since it comes into rolling contact with the teeth of the external tooth member 22, in addition to having the same effect as the invention of claim 1, when the input shaft 1 is rotated without hydraulic pressure, or when the output screw shaft 2 When a reaction force is applied, the internal tooth member 21 and the external tooth member 22
When they perform a sliding motion, they can operate smoothly even if their machining accuracy is not good, and there is an effect that it is not necessary to rotate the input shaft 1 with a large force.

[Brief description of the drawings]

FIG. 1 is a partially longitudinal front view of a first embodiment of the present invention.

FIG. 2 is an enlarged vertical cross-sectional view when a portion surrounded by a line 2 in the above is neutral.

FIG. 3 is a side view of the amplifying unit as viewed along line 3-3 in FIG.

FIG. 4 is an enlarged partial longitudinal sectional view of a main part of the above.

FIG. 5 is an enlarged vertical cross-sectional view of a portion surrounded by line 2 in FIG. 1 when rotating clockwise.

FIG. 6 is an enlarged partial longitudinal sectional view of a main part of the above.

FIG. 7 is a partially longitudinal front view of a second embodiment of the present invention.

FIG. 8 is a side view of the amplifier section taken along line 8-8 in FIG.

FIG. 9 is a drawing similar to FIG. 1 of a conventional hydraulic steering device.

FIG. 10 is an enlarged vertical cross-sectional view when a portion surrounded by a line 7 in the above is neutral.

FIG. 11 is a partially cut-away slope drawing of the whole.

FIG. 12 is a cross-sectional plan view of a half part of the control valve according to the third embodiment.

FIG. 13 is a partially cut-away slope drawing of the whole during rotation of the same.

FIG. 14 is a cross-sectional plan view of a half of the control valve of the above.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Input shaft 2 Output screw shaft 3 Screw part 4 Rack part 6 Housing 7 Inlet port 8 Outlet port 9 Switching valve 10 Torque generator 11 Spool 12 Sleeve 13 Cylinder 14 Centering spring 16 Stopper pin 17 Second drive shaft 19 Amplifying part 21 Internal teeth Member 22 External tooth member 24 Ring member 25 Depression 26 Spline 27 Second drive shaft 28 Roller 32 First annular groove 33 First through hole 34 Second annular groove 35 First communication groove 36 Second through hole 37 Second communication groove 38 Third annular groove 39 Third through hole 40 Fourth annular groove 42 Third communication hole

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-25773 (JP, A) JP-A-56-47362 (JP, A) JP-A-2-164673 (JP, A) Jpn. 16974 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) B62D 5/00-5/32

Claims (2)

(57) [Claims] 1. An input shaft 1 coupled to a handle, an output screw shaft 2 interlocked with the input shaft 1, and an output screw shaft 2
And a tie rod 5 connected to a steering wheel and steering the steering wheel, the input shaft is a torque generator 10
The torque generator 10 is connected to the output screw shaft 2 through a housing 6 having an inlet port 7 and an outlet port 8, an internal tooth member 21, and an internal tooth member 21. Amplifying section 19 having an external tooth member 22 that revolves with each other, and each port operated by the input shaft 1 and the amplifying section 19
And a switching valve 9 for controlling the flow of fluid to the output screw shaft 2, wherein the output screw shaft 2 is operated by the power of the amplifier 19. 2. The hydraulic steering apparatus according to claim 1, wherein the internal gear member 21 includes a ring member 24 and a roller 28 which is slidably fitted in a semicircular recess 25 provided in the ring member 24.