JPH0218264B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power cylinder device mounted on a vehicle to reduce the steering torque applied to a steered wheel to steer the wheels, and more specifically, to a power cylinder device formed on a piston rod of a power cylinder. The present invention relates to a power cylinder device in which the elastic force of an elastic pressure means for reliably meshing a rack portion with a pinion portion of a pinion shaft is prevented from being influenced by the hydraulic pressure of hydraulic oil supplied inside the power cylinder.

Many vehicles have a power system that reduces the steering torque that the driver needs to apply to the steered wheels when steering the front wheels, and allows the front wheels to be steered using hydraulic auxiliary power. A cylinder is installed. The piston rod of the power cylinder slides linearly by the hydraulic pressure of hydraulic oil supplied inside the power cylinder to assist in steering the front wheels.

By the way, a rack part is formed on the piston rod of the power cylinder to move the hydraulic oil supply chamber inside the power cylinder by sliding of the piston rod, and the pinion part of the pinion shaft is engaged with the rack part.
There are cases where the rotation of the pinion shaft caused by the linear sliding of the piston rod is used to perform operations on the vehicle other than front wheel steering. An example of such an operation on a vehicle is a rear wheel steering operation by a steering device previously provided by the present applicant, which is capable of steering both front wheels and rear wheels by steering operation of a steering wheel. In the steering device, the pinion shaft constitutes a part of the path for transmitting the rear wheel steering force from the steered wheels to the rear wheel steering mechanism, and the rear wheels are steered by rotating the pinion shaft. Ru.

In the above, in order to ensure that the rack part formed on the piston rod of the power cylinder and the pinion part formed on the pinion shaft are meshed with each other, and to ensure that the sliding force of the piston rod is transmitted to the pinion shaft with a predetermined meshing force. The power cylinder is provided with a pressure means. The pressing means includes at least a receiving member for receiving the piston rod surface opposite to the surface on which the rack portion is formed, and an elastic member such as a spring disposed in a space on the back side of the receiving member. , the elastic force of the elastic member acts as an elastic force on the piston rod via the receiving member,
The rack part is meshed with the pinion part with a predetermined meshing force.

By the way, as mentioned above, since the rack portion is formed on the piston rod so as to move in the hydraulic oil supply chamber, the receiving member faces the hydraulic oil supply chamber. The hydraulic pressure of the hydraulic oil supplied to the hydraulic oil supply chamber acts on the outer periphery of the piston rod, but since the receiving member is in contact with a part of the piston rod, the surface of the piston rod that is not in contact with the receiving member, i.e. The total hydraulic pressure acting on the surface of the piston rod on which the rack is formed is greater than the total hydraulic pressure acting on the surface of the piston rod in contact with the receiving member. Therefore, the total hydraulic pressure difference reduces the elastic force of the elastic pressure means, and as a result, it affects the meshing state between the rack part and the pinion part. There may be cases where the adjustment force cannot be obtained as expected.

The present invention includes a power cylinder used in a steering device that steers both the front wheels and the rear wheels by the steering operation of the steering wheel, and includes an elastic pressure means for obtaining an engaging force between the rack part of the piston rod and the pinion part of the pinion shaft. This was done in order to solve the above-mentioned problems regarding the elastic force in a power cylinder provided with a power cylinder.

An object of the present invention is to form a rack part in a power cylinder, engage a pinion part of a pinion shaft with the rack part, and apply a resilient force to the surface of the piston rod opposite to the rack part. a receiving member that faces the hydraulic oil supply chamber formed inside the power cylinder and receives the surface of the piston rod, and an elastic member such as a spring disposed in a space on the back side of the receiving member. In addition, the receiving member is formed with a communication part such as a groove or a hole that communicates the hydraulic oil supply chamber with the space, and the communication part allows the hydraulic oil in the hydraulic oil supply chamber to be communicated with the space. The hydraulic pressure of the hydraulic oil is caused to flow into the space and act on the receiving member from the space side, thereby making it possible to eliminate the total difference in hydraulic pressure acting on the piston rod, and by applying a predetermined elastic force of the elastic force to the rack part. An object of the present invention is to provide a power cylinder device for a vehicle in which a pinion portion and a pinion portion can be engaged with each other.

A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

Figure 1 is a plan view of a four-wheeled vehicle, with left and right front wheels 1,
1 is supported by knuckle arms 2, 2 which are rotatable left and right about shafts 2a, 2a, and has left and right front wheel steering tie rods 3, 3 whose outer ends are connected to the front wheel knuckle arms 2, 2. By moving in the left-right direction, that is, in the vehicle width direction, the front wheels 1, 1 are steered by rotation of the knuckle arms 2, 2. The left and right rear wheels 4, 4 are also supported by knuckle arms 5, 5 which are rotatable left and right about shafts 5a, 5a, like the front wheels, and their outer ends are connected to the rear wheel knuckle arms 5, 5. When the left and right rear wheel steering tie rods 6, 6 move in the left-right direction, the rear wheels 4, 4 are steered by the rotation of the knuckle arms 5, 5.
The front wheel knuckle arm 2 is suspended on the vehicle body by a front wheel suspension mechanism consisting of a lower arm 7, a shock absorber, etc., and the rear wheel knuckle arm 5 is also suspended on the vehicle body by a rear wheel suspension mechanism consisting of a lower arm 8, a shock absorber, etc. .

A steering shaft 1 is attached to a steering wheel 9 on which a driver performs a steering operation.
The steering shaft 10 includes a main shaft 11, an intermediate shaft 12, and an output shaft 13 connected in series. Second
As shown in the figure, the output shaft 13 is rotatably supported inside the gear box 14 by bearings 15 and 16, and the output shaft 13 is integrally formed with a pinion portion 13a. As shown in FIGS. 1 and 3, the gearbox 14 has a long cylindrical shape extending in the left-right direction, and a shaft 17 is slidably inserted therein, with each end of the shaft 17 protruding from both ends of the gearbox 14. The inner ends of the front wheel steering tie rods 3, 3 are connected to. A rack portion 17a is formed on the shaft 17 as shown in FIG. 2, and the pinion portion 13a meshes with the rack portion 17a formed in the longitudinal direction of the shaft 17. Therefore, when the steering wheel 9 is rotated, the steering shaft 1
The shaft 17 to which the steering torque is transmitted through the shaft 17 performs a left-right linear movement, and the front wheels 1, 1 are steered by the left-right movement of the tie rods 3, 3. Axis 1 above
7. The tie rods 3 constitute a front wheel steering mechanism 18 provided at the front of the vehicle.

As shown in FIG. 3, a rack portion 17b separate from the rack portion 17a is formed on the shaft 17.
The pinion portion 19a meshes with the pinion portion 7b. The pinion portion 19a is formed integrally with the front end of the connecting shaft 19 shown in FIG.
A connecting shaft 19 rotatably supported by the shaft 17 extends diagonally rearward and downward from the shaft 17. Connecting shaft 19 as shown in Figure 1
The front end of hydraulic oil 22 whose length direction is the longitudinal direction of the vehicle is connected to the rear end via a universal joint 23, and the front end of a rotating shaft 24 is connected to the rear end of the operating shaft 22 via a universal joint 25. Concatenated. As shown in FIG. 6, the rotation shaft 24, which extends diagonally upward and rearward from the hydraulic oil 22, is connected to a bearing 2 inside a gearbox 26.
It is rotatably supported at 7 and 28. The operating shaft 22 is installed on the lower surface of the floor component of the vehicle so as to be exposed outside the vehicle interior, and a cylindrical cover member 29 is fitted over substantially the entire length of the outer circumference of the operating shaft 22 to protect the operating shaft 22. will be combined.

The connecting shaft 19 is rotated by the horizontal linear movement of the shaft 17 caused by the steering operation of the steering wheel 9, and the rotation of the connecting shaft 19 is caused by an operating shaft rotatably supported by a bearing 30 inside the cover member 29. 22 to the rotation shaft 24, the rotation shaft 24 rotates in conjunction with the steering wheel 9. When the rotation shaft 24 rotates, the rear wheel steering mechanism 31 operates and the rear wheels 4 are steered.
1 serves as an input shaft for inputting the rear wheel steering force.

Next, the structure of the rear wheel steering mechanism 31 will be explained.

As shown in FIG. 6, a pin 32 is connected to the rear end of the input shaft 24 protruding from the gear box 26 with an eccentricity ε shifted in the radial direction of the input shaft 24. The connection is performed by connecting the block 33 fixed to the input shaft 24 and the block 34 fixedly holding the pin 32 with a bolt 36 with a spacer 35 interposed. 8th
The figure shows a plan sectional view showing the structure behind the input shaft 24, one end of a connecting rod 37 is connected to the pin 32, and a tie rod connecting member 39 is connected to the other end of the connecting rod 37 via a pin 38. . The tie rod connecting member 39 is a member that connects the left and right rear wheel steering tie rods 6, 6. The inner ends of the tie rods 6, 6 are connected to both ends of the connecting member 39, and a holding frame attached to the vehicle body is connected to the tie rod connecting member 39. 40,
The tie rod connecting member 39 is supported by bearings 42 and 43 of 41 and is movable left and right. The connection between the eccentric pin 32 and connecting rod 37, the connection between the pin 38 and the tie rod connection member 39, and the connection between the tie rod connection member 39 and the tie rods 6, 6 are performed using ball joints 44, 45, 46, 46.
This is done by Since the pin 32 is eccentric from the input shaft 24, the structure around the input shaft 24 and the pin 32 is a crank mechanism, and when the input shaft 24 rotates in conjunction with the steering wheel 9, it rotates around the input shaft 24. The connecting rod 37 is caused to move horizontally by the eccentric pin 32, and the tie rod connecting member 39 moves horizontally by the amount of the horizontal movement component of the pin 32, thereby steering the rear wheels 4, 4. This is accomplished together with front wheel steering by the front wheel steering mechanism 18. The above eccentric pin 32, connecting rod 37, tie rod connecting member 39, rear wheel steering tie rod 6,
Rear wheel steering mechanism 3 provided at the rear of the vehicle by 6
1 is configured.

When the steering wheel 9 is in the neutral rotation position, in other words, when the vehicle is traveling straight, the eccentric pin 32 is set to be located directly below the input shaft 24, as shown in FIG. When the rotation angle of the input shaft 24 is a small angle between 0° and 180°, and when the rotation angle is a large angle between 180° and 360°, the tie rod connecting member 39 is connected to the input shaft 2.
4 is moving in the left and right directions opposite to the original position when the rotation angle of wheel 4 is 0°. Therefore, in a small steering angle operation of steering wheel 9 that rotates input shaft 24 by a small angle, rear wheel 4 is moved by front wheel 1. In a large steering angle operation of the steered wheels 9 that turns the input shaft 24 by a large angle in the same direction as the front wheels 1, the rear wheels 4 can be turned in the opposite direction to the front wheels 1. Further, the rotation angle ratio of the steering wheel 9 and the input shaft 24 is set such that the rotation angle of the input shaft 24 is changed when the steering wheel 9 is operated by a large steering angle.
If you set it to 180° or around 180°,
By operating the steering wheel 9 to a large steering angle, the turning angle of the rear wheels 4 can be returned to 0° or around 0°.

As described above, the steering torque applied to the steered wheels 9 is transmitted to the front wheel steering mechanism 18 via the steering shaft 10 shown in FIG. 1 and the shaft 17 inserted through the gearbox 14. The wheels 9 and the front wheel steering mechanism 18 are connected via a steering torque transmission path 47 made up of a steering shaft 10 and a shaft 17. Here, the shaft 17 is also a component of the front wheel steering mechanism 18,
It is also a component of the steering torque transmission path 47. The front wheel steering mechanism 18 and the rear wheel steering mechanism 31 are connected by the connecting shaft 19, the operating shaft 22, and the input shaft 24, and these connecting shafts, the operating shaft 22, and the input shaft 24
The front/rear wheel steering mechanism 1 is connected by a connecting path 48 consisting of
8,31 connections are made. The steering torque transmission path 47 serves as a front wheel steering force transmission path from the steering wheel 9 to the front wheel steering mechanism 18, and the rear wheel steering force transmission path from the steering wheel 9 to the rear wheel steering mechanism 31 serves as a steering torque transmission path. Since it is constituted by the transmission path 47 and the connection path 48, the front wheel steering force transmission path and the rear wheel steering force transmission path overlap in the steering torque transmission path 47 and are shared. Therefore, it is possible to configure the front wheel steering force transmission path and the rear wheel steering force transmission path by using a path configuring member that serves both, thereby simplifying the path configuration.

As shown in FIG. 3, the shaft 17 inserted into the gearbox 14 is provided with a piston portion 17c, so that the piston portion 17c defines left and right hydraulic oil supply chambers S ₁ and S ₂ inside the gearbox 14. . In this way, the gearbox 14 is connected to the power cylinder 49.
The shaft 17 is the piston rod of the power cylinder 49, and the power cylinder 49 is a power cylinder for the front wheels.
Since the piston rod 17 is formed with the rack portion 17b as shown in FIGS. 3 and 4, with which the pinion portion 19a of the connecting shaft 19, which is the tip shaft of the connecting path 48, engages, the front wheel steering mechanism A front wheel power cylinder 49 disposed at the front of the vehicle like 18 is connected to the front of the connecting passage 48 . On the other hand, a rear wheel power cylinder 50 is connected to the rear part of the connection path 48 as shown in FIG. 1, and the specific structure of the rear wheel power cylinder 50 is shown in FIGS. 6 and 8. A pinion portion 24a is integrally formed on the input shaft 24 inserted through the gear box 26, and the pinion portion 24a meshes with a rack portion 51a of a piston rod 51 whose axial direction is the left-right direction of the power cylinder 50 for rear wheels. . As a result, the rear wheel power cylinder 50, which is disposed at the rear of the vehicle like the rear wheel steering mechanism 31, is connected to the input shaft 24, which is the terminal shaft of the connecting path 48, in the connecting path 48.
Connected to the rear of 8. As shown in FIG. 8, inside the cylinder barrel 52 into which the piston rod 51 is slidably inserted, left and right hydraulic oil supply chambers S ₃ and S ₄ are defined by the piston portion 51b of the piston rod 51, and the cylinder barrel 52 is integrally connected to the gear box 26 with a bolt 53.

Power cylinders 49, 50 for front wheels and rear wheels
The steering wheels 9 are installed in the left and right hydraulic oil supply chambers S ₁ , S ₂ , S ₃ , and S _{4 .}
A switching valve 54 that selectively supplies hydraulic oil depending on the steering direction of the vehicle is shown in FIG. The switching valve 54 is an open center type four-way switching valve, and is formed integrally with the lower part of the output shaft 13 of the steering shaft 10. Valve housing 5 housing switching valve 54
5 is integrally connected to the gearbox 14.
As shown in FIG. 1, the internal chamber of the valve housing 55 is connected to an oil tank 59 through an outward hydraulic pressure line 57 and a return hydraulic line 58 in which an oil pump 56 is interposed. Furthermore, the inner chamber of the valve housing 55 is connected to the gearbox 1.
4, that is, the front wheel power cylinder 49 is connected to the left and right hydraulic oil supply chambers S _{1 and S 2 by an oil passage formed in the wall of the cylinder barrel, and is also connected to the left and right hydraulic oil supply chambers S 1} and S ₂ from the front of the vehicle to the rear of the vehicle. It is also connected to the hydraulic oil supply chambers S ₃ and S ₄ of the power cylinder 50 for the rear wheels through extended hydraulic pipes 60 and 61 . Hydraulic oil from the oil tank 59 is supplied to the power cylinder 50 for the rear wheels.
These hydraulic conduits 60 and 61 are routed into the vehicle interior through the underside of the seat 62, and are therefore protected from harmful effects outside the vehicle interior, such as mud.

As shown in FIG. 2, the teeth of the pinion portion 13a of the output shaft 13 equipped with the switching valve 54 are helical teeth, and the teeth of the pinion portion 13a of the output shaft 13 equipped with the switching valve 54 are helical teeth, and the teeth of the piston rod 17 of the front wheel power cylinder 50 are engaged with the pinion portion 13a.
The teeth a are also corresponding helical teeth. Therefore, when the steering torque due to the turning operation of the steering wheel 9 is transmitted to the output shaft 13, a thrust force in the axial direction is generated on the output shaft 13, which causes the switching valve 54 to rotate, although slightly. The switching valve 54 moves forward or backward depending on the direction in which the steering wheel 9 is steered, and the operating oil is switched by the switching valve 54. Hydraulic oil is selectively supplied to the hydraulic oil supply chamber via the hydraulic passage and the hydraulic pipe line.
The switching operation principle of such a switching valve using helical teeth is the same as a known one.

Front wheel power cylinder 49 supplied with hydraulic oil
The piston rod 17 slides in the left and right direction by the hydraulic pressure acting on the piston portion 17c shown in FIG. The piston rod 51 of the rear wheel power cylinder 50 to which oil is supplied is connected to the piston portion 5 shown in FIG.
The input shaft 24 is slid in the left-right direction by the hydraulic pressure acting on the piston rod 1b, and the rotation of the input shaft 24 is achieved by adding the sliding force of the piston rod 51. Therefore, the rear wheel steering operation is performed using the auxiliary power of the rear wheel power cylinder 50. Therefore, the steering torque that the driver must apply to the steered wheels 9 to steer the front and rear wheels 1 and 4 is reduced.

Here, the steering torque can be reduced even if only one of the front wheel power cylinder 49 and the rear wheel power cylinder 50 is mounted on the vehicle, and one power cylinder is used for both the front and rear wheels. In this case, in order to transmit the auxiliary power of the power cylinder to both the front wheel steering mechanism 18 and the rear wheel steering mechanism 31, a path constituting member of the connection path 48 connecting these mechanisms 18 and 31 is required. It is necessary to increase the mechanical strength and rigidity by increasing the diameters of the connecting shaft 19, the operating shaft 22, and the input shaft 24. On the other hand, in this device, as mentioned above, the two power cylinders 49 and 50 for the front wheels and the rear wheels are connected to the front and rear of the connection path 48.
The auxiliary power of the front wheel power cylinder 49 can be directly transmitted to the front wheel steering mechanism 18, and the auxiliary power of the rear wheel power cylinder 50 can be directly transmitted to the rear wheel steering mechanism 31, respectively.
This has the advantage that the connecting shaft 19, the operating shaft 22, and the input shaft 24 can be made smaller in diameter.

As is clear from the above description, the present invention employs a rack-and-pinion mechanism for converting rotational motion into linear motion, or converting linear motion into rotational motion. In order to reliably change the direction of motion and reliably transmit the wheel steering force, it is necessary to set the meshing depth between the rack and pinion parts to a predetermined depth and to maintain an appropriate meshing force at all times. It is. For this reason, Figures 2, 3, 4, and 6
As shown in the figure, pinion parts 13a, 19
Rack portions 17a, 17b, which mesh with a, 24a,
The spring force of springs 63, 64, 65, which are elastic members, is applied to the surface of the piston rods 17, 51 opposite to the surface on which the piston rods 51a are formed.

The spring 63 shown in FIG.
6. The retracting member 67 constitutes a pressing means 68. The receiving member 66 is slidably inserted into the cylindrical guide portion 14b of the gearbox 14, and the rack portion 17 is inserted into the recess 66a formed on the front surface.
Receive the surface of the piston rod 17 opposite to a. The reciprocating member 67 has a short shaft bolt shape with a hexagonal head 67a at the outer end and a male threaded portion 67b formed on the outer circumferential surface, and is screwed into the male threaded portion 14c formed on the inner circumferential surface of the guide portion 14b. Matched. When the advancing/retracting member 67 is screwed in the hexagonal head 67a, the spring force of the spring 63 interposed between the advancing/retracting member 67 and the receiving member 66 is increased or decreased by the forward or backward movement of the advancing/retracting member 67. The rack portion 17a of the piston rod 17 meshes with the pinion portion 13a of the output shaft 13 by the elastic force of the elastic pressure means 68 due to the spring force.

The pressure means 69 shown in FIGS. 3 and 4 has the same structure as the pressure means 68 described above, and is slidably inserted into the cylindrical guide portion 14d of the gearbox 14, and is located on the opposite side of the rack portion 17b. A receiving member 70 having a concave portion 70a formed on the upper surface for receiving the surface of the piston rod 17, a short-shaft bolt-shaped reciprocating member 71 having a hexagonal head 71a and screwed onto the guide portion 14d, and a reciprocating member 71 that moves forward and backward with the receiving member 70. A spring 64 interposed between the member 71 and the spring 64 constitutes a resilient means 69 for resiliently engaging the rack portion 17b of the piston rod 17 with the pinion portion 19a of the connecting shaft 19.

The pressing means 72 shown in FIG. 6 also includes a receiving member 73, a reciprocating member 74, and a spring 65.

As is clear from the above, power cylinder 4 for front wheels
The piston rod 17 of 9 has a different rack part 17.
a, 17b are formed, and the output shaft 13, which is a separate pinion shaft, and the pinion parts 13a, 19a of the connecting shaft 19 mesh with these rack parts 17a, 17b, and the respective meshes are caused by elastic pressure. This is done by applying the elastic force of the means 68, 69. In this way, when there are two meshing parts between the rack and pinion parts on the same shaft, adjusting the elastic force of one of the elastic means will cause the piston rod 17 to move slightly due to flexural deformation in the elastic direction. ,
There is a possibility that the meshing state between the specific rack part and the pinion part by the other pressing means will be affected.

FIG. 5 shows the rack part 17 of the piston rod 17.
FIG. 3 is a cross-sectional view of the piston rod 17 showing the meshing positional relationship between the pinion portions 13a and 19a of the output shaft 13 and the connecting shaft 19; Pinion part 13
Since the angles a and 19a form an angle θ, the rack portions 17a and 17b are formed on the outer peripheral surface of the piston rod 17 at an angle θ. When the angle θ is 0° or 180°, that is, the pinion parts 13a and 19
If there is no angle between the rack portions 17a and 17b, the elastic force of one of the two pressure means 68, 69, for example, the pressure means 68, may be adjusted to separate the rack portion 17a and the pinion portion 13a. By adjusting the meshing state of
9a, the meshing state between the rack portion 17b and the pinion portion 19a changes. In order to solve this problem, the rack portions 17a and 17b and the pinion portions 13a and 19a form an angle, and the direction of movement of the piston rod 17 by adjusting the elastic force of the elastic pressure means 68 is adjusted to the depth of engagement between the rack portion 17b and the pinion portion 19a. What is necessary is to configure it so that it is deviated from the horizontal direction. Rack part 17
This problem is most effectively solved when the angle θ formed between a and pinion parts 13a and 17b and between pinion parts 13a and 19a is 90°, and ideally it is preferable that the angle θ is 90°. , it becomes practical even if the angle θ is set to an angle other than 0° and 180° due to restrictions imposed on design such as component arrangement.

As is clear from FIG. 3, the pinion portion 19a of the connecting shaft 19 and the rack portion 17b of the piston rod 17
A pressure means 69 for engaging the front wheel power cylinder 49 is provided in the left hydraulic oil supply chamber _S1 of the front wheel power cylinder 49,
The receiving member 70 constituting the pressure means 69 faces the hydraulic oil supply chamber _S1 . Also, the rack part 17
b is formed on the piston rod 17 so as to move in the hydraulic oil supply chamber _S1 , and the pressure means 69 faces the pinion portion 19a with the piston rod 17 in between. The hydraulic pressure of the hydraulic oil supplied to the chamber _S1 acts on the outer periphery of the piston rod 17, but since the receiving member 70 is in contact with a part of the lower surface of the piston rod 17, the hydraulic pressure acting on the upper surface of the piston rod 17 is reduced. The total is the piston rod 17 and the receiving member 70.
The area of contact with the piston rod 17 is larger than the total hydraulic pressure acting on the lower surface of the piston rod 17. Since the receiving member 70 is in close slidable contact with the inner circumferential surface of the cylindrical guide portion 14d, the space on the back side of the receiving member 70 in which the spring 64 is housed, that is, the space between the receiving member 70 and the reciprocating member 71 is closed. the space between
_S5 is isolated from the hydraulic oil supply chamber _S1 . For this reason, even if the spring force of the spring 64 is increased or decreased by screwing the advance/retreat member 71 and the elastic force of the elastic force of the elastic pressure means 69 is adjusted, the difference in the total hydraulic pressure between the upper and lower surfaces of the piston rod 17 prevents the piston rod 17 from reaching a predetermined level. Sometimes it is not possible to obtain the force of compression.

Therefore, a communication groove part 73 is formed in the recessed part 70a of the receiving member 70 that contacts the piston rod 17, and the end thereof opens and faces the hydraulic oil supply chamber _S1 , and the communication groove part 73 and the space _S5 are connected by a communication hole. The connection is made through the section 74. As a result, the hydraulic oil supply chamber S ₁ and the space S ₅ communicate with each other through a communication section 75 formed in the receiving member 70, which is composed of a communication groove section 73 and a communication hole section 74, and the hydraulic oil in the hydraulic oil supply chamber S ₁ is communicated with the space S 5 . Flows into _S5 . As a result, the difference in the total hydraulic pressure on the upper and lower surfaces of the piston rod 17 is eliminated by the total hydraulic pressure acting on the receiving member 70 from the space _S5 side, and the spring force of the spring 64 is applied to engage the pinion portion 19a and the rack portion 17b. It can be used as is as the elastic force of the elastic pressure means 69 to cause the force to move.

As is clear from the above description, according to the present invention,
The power cylinder is provided with a resilient means for meshing a rack portion formed on a piston rod of the power cylinder with a pinion portion formed on a pinion shaft, and a receiving member constituting the resilient means is arranged to face a hydraulic oil supply chamber of the power cylinder. However, since communication parts such as grooves and holes are formed in the receiving member to communicate the hydraulic oil supply chamber and the space on the back side of the receiving member, the hydraulic oil in the hydraulic oil supply chamber can flow into the space and from the space side. It is now possible to apply hydraulic pressure to the receiving member, which eliminates the difference in the total working hydraulic pressure of the piston rod that occurs when the receiving member contacts a part of the piston rod. It becomes possible to mesh the part and the pinion part.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, in which Fig. 1 is an overall plan view of the vehicle, Fig. 2 is a side cross-sectional view of the vicinity of the steering shaft and the power cylinder for the front wheels, and Fig. 3 is a partial cross-section of the power cylinder for the front wheels. Rear view, Figure 4 is 4- in Figure 3.
Fig. 5 is a side sectional view of the piston rod showing the positional relationship between the rack part of the piston rod of the front wheel power cylinder and the pinion part that meshes with the rack part, and Fig. 6 is a side sectional view of the piston rod connected to the rear wheel steering mechanism. A side sectional view around the input shaft, Figure 7 is 7A-7A in Figure 6,
FIG. 8, which is a composite half-cut view taken along the line 7B-7B, is a plan sectional view of the vicinity of the rear wheel steering mechanism. In the drawing, 1 is the front wheel, 4 is the rear wheel, 9 is the steering wheel,
17 is the piston rod, 17b is the rack part, 18
1 is a front wheel steering mechanism, 19 is a connecting shaft which is a pinion shaft, 19a is a pinion part, 31 is a rear wheel steering mechanism,
47 is a steering torque transmission path, 48 is a connection path, 4
9 is a power cylinder for the front wheels, 50 is a power cylinder for the rear wheels, 60 and 61 are hydraulic pipes, 64 is a spring which is an elastic member, 69 is an elastic member, 70 is a receiving member, 75 is a communication portion, and S ₅ is a space It is.

Claims (1)

[Claims] 1. A rack part is formed on the piston rod of the power cylinder, and the pinion part of the pinion shaft is engaged with the rack part, and an elastic force is applied to the surface of the piston rod on the opposite side from the rack part. The pressure means includes at least a receiving member facing a hydraulic oil supply chamber formed inside the power cylinder and receiving the surface of the piston rod, and an elastic member disposed in a space on the back side of the receiving member. A power source for a vehicle, characterized in that the receiving member is formed with a communication portion such as a groove or a hole for communicating the hydraulic oil supply chamber with the space and allowing oil in the hydraulic oil supply chamber to flow into the space. cylinder device.