JPH04138981A - Assembling method of rear wheel steering device for vehicle - Google Patents

Abstract

PURPOSE:To perform connection of two systems in a manner that the neutral position of a machine system coincides with that of a hydraulic system by assembling the support part on the car body side of a displacement transmitting means after the fulcrum on the rear wheel steering shaft side of the displacement transmitting means is set to a neutral position, and thereafter, assembling a hydraulic switch valve. CONSTITUTION:In assembly of a machine system to displace a rear wheel steering shaft 13 and a hydraulic system to assist displacement thereof, after the engaging end part D side of a cross lever 14a is inserted in a swing seal 56, an output rod member 16 and a yoke assembly 18 are assembled, and the angle positions of the yoke assembly 18 and an input shaft 26 are respectively regulated to a neutral position. The rear wheel steering shaft 13 engaged with an engaging end part B of the cross lever 14a is assembled to decide the neutral position of the rear wheel steering shaft 13. Thereafter, after a support 38 is engaged with an engaging end part C of the cross lever 14a, it is secured to a car body. After, as noted above, regulation of the neutral position of the machine system and a work to fix fulcrums A-C of the cross lever 14a are completed, a valve spool 42 of a hydraulic switching valve 15 is engaged with the engaging end part C of the valve spool 42.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for assembling a vehicle rear wheel steering system in which a rear wheel steering shaft for steering the rear wheels is controlled by two systems, a mechanical system and a hydraulic system. It is something.

[Prior Art] Conventionally, as a rear wheel steering device for a vehicle, for example,
As described in Publication No. 273772, a mechanical system that displaces a rear wheel steering shaft that steers the rear wheels includes an input shaft that inputs the amount of steering angle of the front wheels, and an input shaft that receives input from the input shaft and moves the rear wheel steering shaft in the axial direction. The output rod member is provided with a stroke output rod member, and a yoke assembly that is linked to and swingably supported by the output rod member, and that controls the stroke amount of the output rod member due to rotation of the input shaft depending on the swing angle of the yoke assembly. The stroke amount of the output rod member is transmitted to the rear wheel steering shaft by a displacement transmitting means linked to the rod member, the rear wheel steering shaft, and the vehicle body, and the displacement of the rear wheel steering shaft is assisted. The hydraulic system that
It is equipped with a power steering means for hydraulically assisting the displacement of the rear wheel steering shaft, and a hydraulic switching valve for controlling the power steering means, and the displacement transmitting means is inserted through a sealing member attached to a casing of the machine room. It is known that the hydraulic switching valve is linked to the hydraulic switching valve, and the mechanical system and the hydraulic system are connected via the displacement transmitting means.

In such a rear wheel steering device, in the mechanical system, the stroke amount of the output rod member and therefore the displacement amount of the rear wheel steering shaft is determined by the rotation angle of the input shaft and the swing angle of the yoke assembly, and in the hydraulic system, the power steering The means hydraulically assists the rear wheel steering shaft by an amount corresponding to the amount of displacement.

Therefore, in order to accurately control the rear wheel steering axis, that is, the rear wheel steering axis, it is necessary to use a neutral (neutral) It is necessary to connect both systems so that the neutral state (zero phase) of the hydraulic system that hydraulically assists the displacement of the rear wheel steering shaft coincides with the neutral state (zero phase).

[Problems to be Solved by the Invention] Incidentally, when the displacement transmission means connecting the mechanical system and the hydraulic system is linked to the hydraulic switching valve, the displacement transmitting means connects the casing of the machine room housing the mechanical system and the hydraulic switching valve. After being inserted through the valve housing of the valve, it is engaged with a fulcrum portion provided on a spool within the valve. and,
A sealing member is attached to the insertion portion of the casing of the machine room. That is, the displacement transmitting means member is inserted through the seal member, and one end thereof is engaged with the fulcrum portion on the valve spool side.

The fulcrum part on the valve spool side is set on the secondary side (back pressure side) of the valve's operating oil discharge system, and normally a pressure of about 3 to 4 kg/c acts on this back pressure side. Just do it. However, especially in cold regions, the viscosity of the oil increases at the initial stage of startup in winter, so the back pressure increases, and in extreme cases can exceed 20 kg/am''.

On the other hand, the machine room is filled with oil to lubricate the internal gears and sliding parts, so if there is no seal between the valve side and the machine room, high pressure on the valve side will be applied to the machine room. It is conceivable that this could have an adverse effect on the fastening and fixing parts of the machine room cover, which have a large pressure-receiving area.

In other words, the above-mentioned sealing member is provided with the main purpose of preventing an excessive increase in pressure in the machine room due to oil leakage from the hydraulic switching valve side, and normally the shaft member inserted therethrough does not oscillate to some extent. Even if it does, the sealing function can be guaranteed against leakage as long as it is within a certain swing range.
A so-called swinging seal is used, and the swinging range of the displacement transmitting means inserted through the seal is designed so as not to exceed the guaranteed range of the swinging seal.

However, if the displacement transmitting means is assembled with a large eccentricity from the beginning with respect to the seal member, the swing position of the displacement transmitting means may exceed the guaranteed range of the seal member during operation of the rear wheel steering system. As a result of the displacement transmitting means not being able to swing within its original range due to contact with the stopper portion of the sealing member specified, each member linked to the displacement transmitting means (
It is possible that an imbalance occurs in the left and right strokes of the output rod member, rear wheel steering shaft, valve spool, etc. Furthermore, if the eccentricity during assembly is extreme, a predetermined pressure may not be obtained on the primary side of the valve at the initial stage of startup.

Therefore, when assembling the above-mentioned rear wheel steering system, in order to avoid any discrepancy between control between the mechanical system and the hydraulic system, the mechanical system that displaces the rear wheel steering shaft should be set to neutral, and the rear wheel steering shaft should be set to the neutral position. It is necessary to connect both systems so that the neutral position of the hydraulic system that assists hydraulically coincides with the neutral position, and to assemble with the part of the displacement transmitting means inserted into the seal member set at the center position of the seal member. be.

The present invention provides the above vehicle rear wheel steering system in which there is no deviation in control of the rear wheel steering shaft between a mechanical system that displaces the rear wheel steering shaft and a hydraulic system that assists in displacement of the rear wheel steering shaft. An object of the present invention is to provide a method for assembling a vehicle rear wheel steering device that can be assembled so that the portion of the displacement transmitting means inserted into the seal member is always maintained within the guaranteed range of the seal member.

[Means for Solving the Problems] For this reason, the present invention provides a mechanical system that displaces a rear wheel steering shaft that steers the rear wheels, an input shaft that manually controls the amount of steering angle of the front wheels, and an input shaft that receives an input from the input shaft. an output rod member that strokes in the receiving shaft direction; a yoke assembly that is linked to the output rod member and is swingably supported, and that controls the stroke amount of the output rod member due to rotation of the input shaft according to the swing angle of the output rod member; The stroke amount of the output rod member is transmitted to the rear wheel steering shaft by a displacement transmitting means linked to the output rod member, the rear wheel steering shaft, and the vehicle body, and the rear wheel steering The hydraulic system for assisting the displacement of the shaft includes a power steering means for hydraulically assisting the displacement of the rear wheel steering shaft, and a hydraulic switching valve for controlling the power steering means,
A vehicle in which the displacement transmitting means passes through a seal member attached to a casing of a machine room and is linked to the hydraulic switching valve, and the mechanical system and the hydraulic system are connected via the displacement transmitting means. In the method for assembling a rear wheel steering device, a fulcrum on the output rod member side of the displacement transmitting means is adjusted to a neutral position with a portion of the displacement transmitting means inserted through the seal member set at a center position of the seal member. At the same time, after setting the fulcrum on the rear wheel steering shaft side of the displacement transmitting means to a neutral position, the vehicle body side support portion of the displacement transmitting means is set so that the centering state of the seal member and the displacement transmitting means is maintained. After that, the hydraulic switching valve is assembled.

[Effects of the Invention] According to the present invention, the fulcrum on the output rod member side of the displacement transmitting means is set at the neutral position while the portion of the displacement transmitting means that passes through the sealing member is set at the center position of the sealing member. At the same time, after setting the fulcrum on the rear wheel steering shaft side of the displacement transmitting means to a neutral position, the vehicle body side support portion of the displacement transmitting means is maintained in a centered state between the seal member and the displacement transmitting means. After that, assemble the above hydraulic switching valve.
Both systems can be connected so that the neutral of the mechanical system and the neutral of the hydraulic system match, and a portion of the displacement transmitting means inserted into the seal member is set at a center position of the sole member. Can be assembled in any condition.

As a result, the portion of the displacement transmitting means inserted into the sealing member is maintained within the guaranteed range against leakage of the sealing member even during the initial stage of assembly and during device operation. It is possible to reliably prevent the occurrence of problems such as a lack of pressure in the displacement transmitting means and an unbalance of left and right strokes of each member connected to the displacement transmitting means during the operation of the device.

[Example] Embodiments of the present invention will be described in detail below with reference to the drawings.

A vehicle rear wheel steering system 1, which is a premise of the present invention, as shown schematically in FIG. 4, and a hydraulic switching valve 1 as a hydraulic assist means.
5, the rear wheel steering device I steers the rear wheels (not shown) according to a predetermined steering ratio characteristic, that is, according to the front wheel steering angle, and changes the steering ratio according to the vehicle speed. It is configured to allow

The rear wheel steering shaft 13 extends in the vehicle width direction, and has both ends connected to the left and right sides via a pair of left and right tie rods and knuckle arms.
It is connected to a pair of rear wheels, and the rear wheels are steered by stroke displacement of the rear wheel steering shaft 13 in the vehicle width direction.

The stroke displacement of the rear wheel steering shaft 13 in the vehicle width direction is performed by the steering ratio variable means If and the power steering means I2.

The steering ratio variable means 11 changes the steering ratio when steering the rear wheels, and has an output rod member 16 whose stroke displacement in the vehicle width direction is determined according to the amount of steering angle of the front wheels.

As will be described later, the ratio of the displacement amount of the output rod member 16 to the steering angle amount of the front wheels (corresponding to the steering ratio) changes depending on the swing angle of the yoke assembly 18 that is swing-driven by the stepping motor 17. It is configured as follows. The amount of rotation of the stepping motor 17 is appropriately controlled based on a vehicle speed signal output from a vehicle speed sensor (not shown), and the actual amount of rotation of the stepping motor 17 is detected by a steering ratio sensor (not shown). and is feedback-controlled by the detection signal.

Power steering means that controls switching of the hydraulic switching valve 15 according to the stroke displacement amount of the output rod member 16 in the steering ratio variable means 11, and generates a steering force using hydraulic pressure by the hydraulic switching valve 15. 12, the displacement of the rear wheel steering axis I3, and therefore the steering of the rear wheels, is hydraulically assisted.

The steering ratio variable means 11 includes the output rod member 16,
Stepping motor 17 and yoke assembly 18 (
In addition to the swing shaft member 22, the pendulum arm 23, and the swing gear 31), it also includes a bevel gear 21 and a connecting rod 24, and these members 1617.18, 21.24
As shown in detail in FIGS. 7 to 7, it is housed in a casing 25.

The output rod member 16 of the steering ratio variable means 11 is supported by the casing 25 so as to be slidable in the axial direction, and by making a stroke displacement in the axial direction, the output rod member 16 transmits the displacement transmitting means 14 as described later. Through the rear wheel steering shaft 13
is displaced in its axial direction (vehicle width direction), thereby steering the rear wheels linked to both ends of the rear wheel steering mi3.

The bevel gear 21 is connected to the lever 2 of the output rod member 16.
8 is supported by the output rod member 16 via a cylindrical support member 52 so as to be rotatable about an axis coaxial with the output rod member 16 and with the output rod member ]6. Binion 27 at the rear end of input shaft 26 that meshes with bevel gear 21 and inputs the amount of steering angle of the front wheels.
is adapted to rotate around the axis as the handle is rotated.

The swing shaft member 22 has an axis that can be positioned coaxially with the output rod member I6, and is fixed to the swing gear 31. This swing gear 31 is connected to the stepping motor 17
A swing shaft 31 that is perpendicular to the plane of the paper and intersects with the axis g1 of the swing shaft member 22 meshes with the worm 32 that is rotated by the drive of the swing shaft member 22.
a (see FIG. 4), which causes the swing shaft member 22 to rotate at the same time.

Note that the N132a of the worm 32 is coupled to the motor shaft 17a of the stepping motor 17 via a coupling 54 (see FIG. 6).

The pendulum arm 23 is connected to the swing shaft member 22 so as to be able to swing around the axis Q1 of the swing wheel member 22, and the axis Q2 of the pendulum arm 23 coincides with the rotation axis of the swing shaft member 22. The connection position to the swing shaft member 22 is determined so as to pass through the intersection of the swing shaft member 22 with the axis Ql.

Like the rear wheel steering shaft 13, the connecting rod 24 has an axis parallel to the axis Q3 of the output rod member 16,
It is connected to the output rod member 16, the bevel gear 21, and the pendulum arm 23, and links the output rod member 16 and the yoke assembly 18. Connection to the output rod member 16 is achieved by splitting and coupling the intermediate portion of the connecting rod 24 to a lever 28 fixed to the end of the output rod member 16, and connection to the bevel gear 21 is achieved by connecting the connecting rod 24 to a lever 28 fixed to the end of the output rod member 16. The connecting rod 24 is connected to the pendulum arm 23 by inserting one end of the connecting rod 24 into an insertion hole formed in the extension 52a of the supporting member 52, and the connecting rod 24 is connected to the other end of the connecting rod 22 so as to be rotatable in all directions. This is done by inserting the pendulum arm 23 into the insertion hole of the ball joint member 33 that has been inserted.

Therefore, the connecting rod 24 is fixed to the output rod member 16, but is slidable relative to the bevel gear 21 in the direction of the axis e4, and is slidable relative to the pendulum arm 23 in the direction of the axis Q2. It is possible. Note that the axis 122 of the pendulum arm 23 is tilted with respect to the direction orthogonal to the axis e3 due to the rotation of the swing shaft member 22, and the pendulum arm 23 slides in this tilted direction. Since the included angle change between the axis C2 and the axis a4 is absorbed, the component of the force transmitted from the pendulum arm 23 to the connecting rod 24 in the direction orthogonal to the axis a3 of the output rod member 16 is absorbed at the connecting point, Relative movement in the orthogonal direction is possible.

In this way, the pendulum arm 2 in the steering ratio variable means 11
3 (yoke assembly 18) and the connecting rod 24 are connected so that they can move relative to each other in the direction orthogonal to the axis ρ3, so that when the pendulum arm 23 rotates, the The locus of the connecting rod 24 and the connecting point is a circular locus or an elliptical locus on the outer circumferential surface of a cylinder having a predetermined radius centered on the axis 123.

As described above, by connecting the pendulum arm 23 and the connecting rod 24 so that they can move relative to each other in the direction perpendicular to the axis 123 of the output rod member 16, the axis a4 of the connecting rod 24 and the output rod member The angle between the output rod member 16 and the axis a3 can be made constant, and thereby it is possible to prevent a left-right deviation from occurring in the displacement of the output rod member 16.

Further, in the output rod member I6, one end of the output rod 36 is connected to the connecting rod 24 via the lever 28, and the other end of the output rod 36 is fitted into the cylindrical rod guide 35 so as to be displaceable in the direction of the axis a3. The ends of the rod guide 35 and output rod 36 are supported by the casing 25.

The rod guide 35 includes a first cylindrical member 35b having an engaging portion 35a that engages with the engaging end A of the displacement transmitting means 14, and a second cylindrical member 35c screwed onto the first cylindrical member 35b. A spring 37 is interposed between the output rod 36 and the output rod 36.

Therefore, when a displacement in the direction of the axis g3 is transmitted to the output rod 36 by the connecting rod 24, it is normally transmitted from the output rod 36 to the rod guide 35 via the spring 37, and from this rod guide 35 to the engaging portion 35a. The displacement is transmitted to the engaged end A of the engaged displacement transmitting means 14. However, the movement of the engagement end A of the displacement transmission means 14 is restricted, thereby causing the spring 37 to move when the output rod 36 is displaced.
When a load greater than the spring force of is applied to the rod guide 35, the displacement of the output rod 36 is absorbed by the contraction of the spring 37 and is not transmitted to the rod guide 35.

Further, the hydraulic switching valve I5 is connected to the valve housing 4.
1 and the valve housing 4 in the valve housing 41.
1, and a valve spool 42 housed so as to be displaceable in an axis 125 direction parallel to the axis σ3 of the output rod member 16. The valve spool 42 is displaced by the output rod member 16 and the rear wheel steering shaft 13 via a displacement transmission means 14, which will be described in detail below. The supply of hydraulic pressure to the power steering means 12 is controlled by this displacement of the valve spool 42.

In addition, a centering spring 45 is provided on this rear wheel steering shaft 13, and if the hydraulic pressure in the hydraulic switching valve 15 or the power steering means 12 disappears, or if the mechanical system of this rear wheel steering device l is damaged or malfunctions. When the hydraulic system is drained and the hydraulic pressure in the cylinder of the power steering means 12 disappears, the centering spring 45 moves the rear wheel steering shaft 13 to the neutral position, that is, the rear wheels are not steered and are traveling straight. It is configured to be positioned in a certain position and to provide a so-called fail-safe.

The cylinder of the power steering means 12 displaces the rear wheel steering shaft 13 in the vehicle width direction by hydraulic pressure, and the piston 46 is directly fixed to the rear wheel steering shaft 13.
Left and right oil chambers 44 and 43 are formed on the left and right sides of this piston 46.

The displacement transmitting means I4 engages with the output rod member 16 (rod guide 35), the valve spool 42, the rear wheel steering shaft 13, and the vehicle body (support support 38), and is caused by the displacement of the output rod member 16. Above valve spool 4
2 in a predetermined direction, and is also actuated in a direction to displace the valve spool 42 in the opposite direction by the displacement of the rear wheel steering shaft I3 caused by the displacement of the valve spool 42. It is structured as follows.

Specifically, the displacement transmitting means 14 has a cross lever 14a consisting of a vertical lever and a horizontal lever, and the engagement end A, which is one end of the vertical lever, is connected to the rod guide 35 of the output rod member I6, and the other end is connected to the rod guide 35 of the output rod member I6. The engagement end B, which is the end, is connected to the rear wheel steering shaft 13,
Further, one end of the horizontal lever, which is an engagement end C, is engaged with a support support 38 fixed to the vehicle body, and the other end, which is an engagement end, is engaged with the valve spool 42, respectively.

When the engaging end portion is linked to the valve spool 42, the casing 25 of the machine room housing the mechanical system is connected to the engaging end portion.
After passing through the valve housing 41 of the hydraulic switching valve 15, the valve spool 42 is engaged with a fulcrum portion provided near the end on the back pressure side of the valve spool 42. And, in the insertion part of the cross lever 14a of the casing 25 of the machine room,
A sealing member 56 (see FIGS. 1 and 5), which will be described in detail later, is attached.

The engaging ends A, B, and D are each connected to the output rod member 16.
The rod guide 35, the rear wheel steering shaft 13, and the valve spool 42 are immovably engaged in the axial direction, but movable and rotatable in other directions, and the engaging end C is engaged with the ball joint. It is engaged for rotation and non-movement by an inlet (not shown).

Therefore, if the output rod member 16 is displaced to the right from a state where both the valve spool 42 and the rear wheel steering shaft 13 are in the neutral position, the engagement end A of the cross lever 14a
is displaced to the right together with the output rod member I6, and since tire reaction force and reaction force from the centering spring 45 are acting on the rear wheel steering shaft 13 when the engagement end A is displaced, this engagement end B is immovable in the axial direction, and the bracket engaging end C is also immovable because it is fixed to the support support 38 (vehicle body).
This cross lever 14a is inclined with respect to a straight line connecting the engaging ends B and C. In other words, the cross lever 14a is operated in a direction to displace the valve spool 42 in a predetermined direction, that is, rightward, and is engaged. The valve spool 42 is displaced to the right by the mating end.

When the valve spool 42 is displaced rightward from the neutral position in this way, the oil pressure in the right oil chamber 43 increases, and the left oil chamber 4
4 decreases, and a hydraulic pressure is generated in the power steering means 12 that pushes the rear wheel steering shaft 13 to the left. The hydraulic pressure that pushes the rear wheel steering shaft 13 leftward increases in accordance with the increase in the rightward displacement of the valve spool 42, resulting in a balance position.

When the valve spool 42 is displaced to the right by a predetermined amount from the neutral position to the balance position, the hydraulic pressure of the power steering means 12 generated thereby causes an external force (centering spring force or tire (reaction force, etc.).

When the valve spool 42 is further displaced to the right from this state, the hydraulic pressure generated in the power steering means 12 becomes larger than the external force acting on the rear wheel steering shaft 13, and the rear wheel steering shaft 13 is moved to the right. It is displaced to the left by hydraulic pressure.

Then, when the rear wheel steering shaft 13 is displaced to the left, the engagement end B of the cross lever 14a is connected to the rear wheel steering shaft 13.
At this time, the output rod member 16 is affected by the steering force of the steering wheel, the tire reaction force of the front wheels, etc., so the engaging end A remains stationary, and the engaging end C also remains unchanged. Since it is stationary, the cross lever 14a tilts about the straight line connecting the engagement end A and the engagement end C, and when it returns to the balance position, the displacement of the rear wheel steering shaft 13 stops.

From this state, when the output rod member 16 is further displaced to the right and the valve spool 42 is displaced to the right, the rear wheel steering shaft 13 is displaced to the left in the same manner as above, and the valve spool 42 is returned to the balance position. However, by stopping and repeating this operation, the rear wheel steering shaft 13 is displaced by an amount corresponding to the amount of displacement of the output rod member 16, and the rear wheels are steered according to the amount of displacement.

When the output rod member 16 is displaced to the left, the cross lever 14a, the valve spool 42 and the rear wheel steering shaft 1
3 is simply reversed from the above case, and the operating principle is the same, so the explanation will be omitted. The movement of this valve spool is described in the prior art (Japanese Patent Application Laid-Open No. 1-273
It is basically the same as that of Publication No. 772).

The steering ratio changing control by the steering ratio variable means 11 can be performed based on various factors, and various changing control patterns can be considered.

In this embodiment, based on the vehicle speed, the rear wheels are steered in the opposite phase to the steering wheel and front wheels in low speed ranges to improve turning performance, and in high speed ranges, they are steered in the same phase to improve driving stability. Controlled to improve performance. Note that in this case, the bundle steering and the front wheel steering are always in the same phase.

By the way, the cross lever 1 of the casing 25 in the machine room
4a is inserted, even if the lever 14a swings within a predetermined range, the machine room side and the hydraulic switching valve 1
5, the sealing function can be guaranteed against leakage even if the inserted shaft member undergoes some rocking movement within a certain range. , a so-called swinging seal 56 is provided.

As shown in detail in FIG. 7, the swinging seal 56 includes, for example, a rubber glue seal portion 57a and a guide seal portion 57.
b, and core members 58a and 58b made of, for example, pressed steel plates are disposed inside the lip seal portion 57a, and on the back side of the lip seal portion 57a, for example, a coil-shaped member is tied in an annular shape. A reinforcing ring member 59 is attached to the counterbore hole 25h provided in the casing 25.
On the other hand, the valve 15 is press-fitted from the valve 15 side.

When the crosshair 7<-14a is inserted into the swing seal 56, the lip seal portion 57a is inserted into the swing seal 56.
The outer periphery of 14a is pressed to seal.

At this time, the lip seal 57a and the ring member 59
Due to the elasticity of the cross lever 14a, the insertion portion of the cross lever 14a can be positioned at its center unless a strong external force is applied to the cross lever 14a.

That is, the swinging seal 56 has a self-centering function.

The inner circumferential portion of the core member 58a constitutes a stopper portion for the swinging movement of the shaft member (cross lever 14a) having an outer diameter d, and the swing seal 56 has an inner diameter D of the core member 58a.
With respect to the swinging movement of the cross lever 14a within the range of s,
It is designed to ensure the sealing function, and the swing range of the cross lever 14a is set to be sufficiently large within this guaranteed range. Therefore, by assembling so that the insertion portion of the cross lever 14a is set at the center position of the swing seal 56 in the initial state of assembly, the cross lever 14a
The swing range will not fall outside the above guaranteed range.

Hereinafter, an assembly method for assembling the rear wheel steering device l in such a manner that the neutral of the mechanical system and the neutral of the hydraulic system are aligned and the cross lever 14a is set at the center position of the swing seal 56. I will explain about it.

First, the swinging seal 56 is attached to the casing 25 in the machine room, and the engagement end side of the cross lever 14a is inserted into the swinging seal 56, and then internal parts such as the output rod member 16 and the yoke assembly 18 are inserted. Assemble. Then, the engagement end A of the cross lever 14a is connected to the output rod member 16.
While engaged with the rod guide 35, the angular position of the yoke assembly 18 (that is, the angular position of the swing gear 31) and the angular position of the input shaft 26 are adjusted to neutral positions using a predetermined adjustment method. At this time, each of the above neutral positions is adjusted while maintaining the insertion portion of the cross lever 14a at the center position of the swing seal 56. As a result, two of the four fulcrums A to A of the cross lever 14a
and D are determined.

Then, in this state, the neutral position of the rear wheel steering shaft 13 is determined by assembling the rear wheel steering shaft 13 that engages with the engagement end B of the cross lever 14a. In this case as well, the above assembly work is performed while maintaining the insertion portion of the cross lever 14a at the center position of the swing seal 56. At this point, the positions of the three fulcrums A, B, and D of the cross lever 14a are determined, and therefore the position of the last point C, the support support 38, is also determined.

Thereafter, the support support 38 is engaged with the engagement end C of the cross lever 14a and then fixed to the vehicle body. In this case as well, the above assembly work is performed while maintaining the insertion portion of the cross lever 14a at the center position of the swing seal 56.

At this time, there may be some twisting when the support support 38 is engaged with the engagement end C, but in this case, after engaging the support support 38, release the support support 38 and set it free. The self-centering function of the swing seal 56 returns the support support 38 to a position corresponding to the center position of the swing seal 56, and then the support support 38 is fixed to the vehicle body. The bolt insertion hole of the support support 38 is formed in the shape of an elongated hole (see Fig. 2), and the bolt can be fastened and fixed to the vehicle body while adjusting the slide within the range of the elongated hole 38h. ing.

After completing the neutral adjustment of the mechanical system and fixing the three fulcrums A, B, and C of the cross lever 14a as described above, the hydraulic switching valve 15 is assembled. In this case, the cross lever 14
Since three points A, B, and C among the four fulcrums of a are fixed, the position of the remaining point C is fixed, and therefore,
By engaging the valve spool 42 with this engagement end C, the hydraulic switching valve 15 is
can perform assembly work. The bolt insertion hole of the valve housing 41 of the hydraulic switching valve 15 is formed in an elongated shape or considerably larger than the bolt diameter, and the valve 15 can be assembled with the cross lever 14a fixed as described above. Even when attached, the assembly position can be adjusted without damaging the neutral state and while maintaining the centering state of the cross lever 14a with respect to the swing seal 56.

As described above, according to this embodiment, the insertion portion of the cross lever 14a into the swinging seal 56 is connected to the seal 56.
With the cross lever 14a set at the center position of
While adjusting the engagement end (fulcrum) A on the output rod member 16 side to the neutral position, the rear wheel steering shaft 1 of the lever 14a
After setting the fulcrum B on the 3rd side to the neutral position, turn the lever 1
The support support 38, which is the vehicle body side support part of 4a, is assembled so that the centering state of the swing seal 56 and the cross lever 14a is maintained, and then the hydraulic switching valve 15 is assembled. Therefore, both systems can be connected so that the neutral of the mechanical system and the neutral of the hydraulic system match, and the part of the cross lever 14a inserted into the swing seal 56 is at the center position of the seal 56. It can be assembled in the set state.

As a result, the insertion portion of the cross lever 14a into the swinging seal 56 can be
The swing seal 56 is maintained within a guaranteed range against leakage, and is protected against excessive pressure rise in the machine room, insufficient pressure on the valve 15 side at startup, and left and right strokes of each member linked to the cross lever 14a during device operation. This makes it possible to reliably prevent problems such as imbalance.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, in which FIG. 1 is a schematic configuration diagram of a rear wheel steering device of a vehicle, FIG. 2 is a sectional view of a steering ratio variable means,
Figure 3 is a sectional view taken along line ■-■ in Figure 2, Figure 4 is a sectional view taken along line IV-IV in Figure 2, Figure 5 is a sectional view taken along line V-V in Figure 2, and Figure 6 is a sectional view taken along line IV--IV in Figure 2. The figure shows Vl in Figure 2.
A cross-sectional view taken along the line -VI, and FIG. 7 is an explanatory longitudinal cross-sectional view of the swinging seal. 1... Rear wheel steering device 13... Rear wheel steering shaft 12... Power steering means 14...
...Lever assembly (displacement transmission means) 14a...
... Cross lever 15 ... Hydraulic switching valve 16 ... Output rod member 18 ... Yoke assembly 25 ... Casing 26 ... Input Shaft 56... Swinging seal Fig. 3

Claims (1)

[Claims] (1) A mechanical system that displaces a rear wheel steering shaft that steers the rear wheels includes an input shaft that inputs the amount of steering angle of the front wheels, an output rod member that receives input from the input shaft and strokes in the axial direction, and a yoke assembly that is linked to and swingably supported by the output rod member, and controls the stroke amount of the output rod member due to the rotation of the input shaft according to the swing angle of the yoke assembly; The stroke amount of the output rod member is transmitted to the rear wheel steering shaft by a displacement transmitting means connected to the vehicle body, while the hydraulic system that assists the displacement of the rear wheel steering shaft is configured to transmit the stroke amount of the output rod member to the rear wheel steering shaft. The displacement transmitting means includes a power steering means for hydraulically assisting the displacement of the shaft, and a hydraulic switching valve for controlling the power steering means, and the displacement transmitting means performs the hydraulic switching after passing through a seal member attached to a casing of the machine room. A method for assembling a vehicle rear wheel steering device that is linked to a valve and in which the mechanical system and the hydraulic system are connected via the displacement transmission means, the method comprising: a portion of the displacement transmission means inserted into the seal member; With the seal member set at the center position, the fulcrum on the output rod member side of the displacement transmitting means is adjusted to the neutral position, and the fulcrum on the rear wheel steering shaft side of the displacement transmitting means is set to the neutral position; The vehicle body side support part of the displacement transmission means,
A method for assembling a vehicle rear wheel steering device, comprising assembling the seal member and displacement transmitting means so that a centered state is maintained, and then assembling the hydraulic switching valve.