JPH0650283Y2 - Power steering mechanism for vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a power steering mechanism for a vehicle.

[Prior art and its problems]

The vehicle power steering mechanism includes a power cylinder that uses a part of a relay rod of a steering link mechanism that connects the left and right wheels to be steerable as a piston rod, and a control valve that controls the supply and discharge of pressure oil to and from the power cylinder. There is a mechanism that becomes.

Then, in this kind of power steering mechanism,
Conventionally, the control valve is arranged in a cross shape with respect to the power cylinder, and the control valve and the power cylinder are connected using a connecting pipe. For this reason, not only the piping work is required for assembling the mechanism, but the cost is increased, but also it is necessary to secure a considerably large space required for the piping, and it may not be possible to reduce the size of the mechanism. .

[Means for solving problems]

The present invention has been made to solve the above problems, and the power steering mechanism for a vehicle includes a power cylinder having a piston rod as a part of a relay rod of a steering link mechanism that connects the left and right wheels to each other, and the relay. Pressure oil to the power cylinder by a valve spool formed coaxially and integrally with the other part of the rod, and coaxially and axially slidably mounted on the outer periphery of the valve spool. A valve sleeve that forms a control valve for controlling the supply and discharge of the control valve is integrally provided with an operating rod that moves in the axial direction according to the operation of the steering wheel, and the control valve and the power cylinder are connected to the relay rod. An oil passage is provided.

[Function and effect of device]

In the present invention, a control valve for controlling the supply and discharge of pressure oil to and from the power cylinder is formed coaxially and integrally with a part of the relay rod that also serves as the piston rod of the power cylinder, and on the outer periphery of the valve spool. The control valve is coaxial with the power cylinder because it is constructed coaxially and slidably in the axial direction and is integrally formed with the operating rod that moves in the axial direction according to the operation of the steering wheel. In addition, it can be configured compactly, whereby the mechanism can be downsized. Further, since the power cylinder and the control valve are connected through the oil passage provided on the relay rod, piping is not required, and cost reduction and downsizing of the mechanism can be achieved.

Further, according to the present invention, the operating rod, which is integrally provided with the valve sleeve and is coaxially and slidably mounted on the outer periphery of the valve spool, is moved in the axial direction according to the operation of the steering wheel. Since the configuration is such that the outer member is moved, the valve spool coaxially assembled in the valve sleeve is moved in the axial direction according to the operation of the steering wheel (the inner member is moved). The configuration can be simpler and more compact than the configuration).

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

FIG. 4 schematically shows a front and rear wheel steering vehicle. In the vehicle, a rack bar 11 constituting a front wheel side steering link mechanism 10 is displaced in the left and right direction by operating a steering wheel WS. It is connected via a tie rod 13 to a knuckle arm 12 that gives a steering angle to. A ball joint is provided at each connecting end of the rack bar 11, the knuckle arm 12, and the tie rod 13. Further, the rear wheel steering system is connected to the rack bar 11 via a rotary shaft 20.

The rotary shaft 20 is divided into four shafts, a main shaft 21, a pair of front and rear intermediate shafts 22 and 23, and a pinion shaft 24. The main shaft 21 is an intermediate shaft 22.
And the rack bar 11 via the pinion shaft 24. The main shaft 21 is rotatably supported by the vehicle body and extends from the front portion of the vehicle body to the rear for a predetermined length.

As shown in FIGS. 1 to 4, the rear wheel steering system includes a connecting mechanism A that connects the rotating shaft 20 and the operating rod 30,
A link mechanism B that connects both rear wheels WR and a power steering mechanism C that connects the connection mechanism A and the link mechanism B and assists the force transmitted from the connection mechanism A to the link mechanism B are provided.

The coupling mechanism A includes an input shaft 41, a first coupling body 42, a second coupling body 43, a bush 44, a protrusion 45, a spring 48, and a driving means 50, which are assembled in a housing H assembled in the vehicle body. The input shaft 41 is rotatably assembled to the housing H by a pair of bearings (not shown), and is connected at its tip end to the intermediate shaft 23 of the rotary shaft 20, on which the input shaft 41 is mounted. A ball nut 46 that constitutes a ball screw is assembled with 41. Ball nut 46 is the input shaft
It is designed to move in the axial direction by the rotation of 41,
On one side thereof, rack teeth 46a inclined by an angle θ are integrally formed.

The first connecting body 42 is composed of a first member 42A and a second member 42B that can be divided into two, and a bolt 42C and a lock nut 42D for adjusting the coupling relationship between these two members 42A, 42B. Actuating rod 3 to housing H through bearings 61 and 62 of
It is rotatably assembled around an axis L2 orthogonal to the axis L1 of 0. The first member 42A integrally has a sector wheel 42a1 (inclined by an angle θ with respect to the axis L2) arranged in an arc shape centered on the axis L2 on the outer periphery of the lower portion thereof, 42a1 meshes with the rack teeth 46a of the ball nut 46. The play in the meshing portions of the teeth 42a1 and 46a and the play in the bearing 61 are eliminated by allowing the first member 42A to move downward in the direction of the axis L2 and screwing the holder Ha screwed into the housing H. be able to. The holder Ha is fixed by a lock nut Hb.

The second member 42B includes an annular portion 42b1 that partially surrounds the outer periphery of the operating rod 30 and a pair of shaft portions that extend outward from the annular portion 42b1.
It has 42b2 and 42b3 and is fitted to the inner spline 42a2 provided on the first member 42A by an outer spline 42b4 provided on the shaft portion 42b2 so as to be axially slidable and integrally rotatable. The coaxiality of the members 42A and 42B and the play in the bearing 62 are caused by the bolt 42C screwed to the first member 42A assembled without play, and the head tapered surface 42c1 of the bolt is axially moved. The second member 42 is engaged with the inner hole conical surface 42b5 provided in 42b2.
It can be adjusted by pushing B downward in the direction of the axis L2.

The second connecting body 43 is formed in a ring shape, and the first connecting body 42 is formed.
Is rotatably assembled through a large number of balls 47 in the annular portion 42b1 of the operating rod 30 at the neutral position in the drawing.
It can be rotated around L1. Each ball 47 has an inner peripheral side angled annular surface 42b6, 4 of the annular portion 42b1 of the first connecting body 42.
2b7 and a pair of annular surfaces 43a, 43b (second connecting body) facing each other.
(Formed on the outer peripheral portion of 43) with a retainer (not shown) between the second member 42B of the first connecting body 42
The second connecting body 43 and the second connecting body 43 form a rolling bearing.
A bush 44 is attached to the second connecting body 43.

The bush 44 has a spherical outer peripheral surface that is tiltably assembled to the second connecting body 43, and is urged outward by a spring 48 interposed between the operating rods 30. Spring 48
Has a function of eliminating backlash between the bush 44 and the second connecting body 43, and a function of a return spring for helping the operation rod 30 to return to the illustrated neutral position. The protrusion 45 is provided integrally with the operating rod 30, extends in a direction orthogonal to the axis L1 of the operating rod 30, and
It is slidably fitted in the inner hole 44a provided in the.

The drive means 50 is composed of a drive gear 51, a pinion shaft 52, and an electric motor 53, and has a function of allowing the operation rod 30 to move in the direction of the axis L1 and rotating it about the axis L1. The drive gear 51 has an inner spline 51a and is rotatably assembled to the housing H via bearings 63 and 64 about the axis L1 of the working rod 30. The drive gear 51 is provided on the working rod 30 by the inner spline 51a. The outer spline 30a is fitted so as to be relatively movable in the axial direction. The pinion shaft 52 has a pinion that meshes with the drive gear 51 and is rotatably assembled to the housing H via a bearing (not shown).
It is connected to a rotating shaft (not shown) of the electric motor 53 so that power can be transmitted. The electric motor 53 is attached to the housing H, and is configured so that its forward rotation, stop, and reverse rotation are controlled according to the vehicle speed.

The link mechanism B is formed by connecting a hollow actuating rod 30, a relay rod 71 penetrating through the actuating rod 30, coaxially and slidably, and both left and right ends of the relay rod 71 via ball joints. It is composed of tie rods 72, 73 and knuckle arms 74, 75 connected to the tie rods 72, 73 via ball joints.
Both rear wheels WR are steered by the displacement of 4,75 in the left-right direction. The relay rod 71 includes a first rod 71A that penetrates the actuating rod 30 and has both ends projecting from the actuating rod 30, and a second rod 71B and a third rod 71C that are screwed and connected to the left and right ends of the first rod 71A. , Each rod 71B, 71C
The lock nuts 71D and 71E for fixing the screwing amount of the tie rod 73 allow the length to be adjusted, and the second rod 71B forms a ball joint with the spherical end 73a of the tie rod 73. The socket 71b9 is integrally formed, and a two-sided width portion 71b8 which is fitted to the bearing bush 69 assembled to the housing H to prevent the relay rod 71 from rotating is formed. Further, a spring 31 and a pair of left and right thrust bearings 32, 33 are interposed between the relay rod 71 and the operating rod 30, and the relative axial movement of both rods 30, 71 is elastically transmitted. It is like this.

The power steering mechanism C assists the force transmitted from the operating rod 30 to the relay rod 71, and is composed of a control valve C1, a power cylinder C2, and the like. The control valve C1 is
A spool type control valve, which is a valve sleeve 30b formed on a part of the operating rod 30 and a valve spool 7 formed coaxially on a part of the first rod 71A of the relay rod 71.
The supply port 71a2 formed in the valve spool 71a1 has a through hole 71a3 formed in the first rod 71A and a second port 71a3
It communicates with the inflow port 71b2 provided in the 2nd rod 71B through the through-hole 71b1 provided in the rod 71B, and valve spool 71a1.
Both discharge ports 71a4 formed in the through hole 7 are formed in the first rod 71A.
A through hole 71a5 provided separately from 1a3, a through hole 71a6 extending radially outward from the end of the through hole 71a5 and a through hole 71b3 provided in the second rod 71B, and an outflow provided in the second rod 71B. It communicates with port 71b4. The inflow port 71b2 is connected to the hydraulic pump P, and the outflow port 71b4 is connected to the reservoir T.

On the other hand, the power cylinder C2 forms a left and right pair of oil chambers R1 and R2 by being slidably fitted in the cylinder body Hc formed by utilizing a part of the housing H in the cylinder body Hc. The piston 71c1 is provided, and the piston 71c1 is integrally formed with the third rod 71C of the relay rod 71. The oil chamber R1 on the left side of FIG. 1 has a through hole 71c2 and an inner hole 71c3 provided in the third rod 71C and a through hole 71a7 provided in the first rod 71A.
Through to the left port 71a8 in FIG. 1 formed on the valve spool 71a1, and the oil chamber R2 on the right side in FIG. 1 has a through hole 71c4 provided in the third rod 71C and a through hole 71a6 in the first rod 71A.
Through a through hole 71a9 which is provided separately and in parallel with the right port 71a10 in FIG. 1 formed in the valve spool 71a1.

In this embodiment having such a configuration, when the steering wheel WS is operated, the rack bar 11 is displaced in the left-right direction and the front wheels WF are steered. During this steering, the rotary shaft 20 is rotated by the rack bar 11, the input shaft 41 of the coupling mechanism A is rotated, the ball nut 46 is moved, and the first coupling body 42 rotates about its axis L2.

Then, when the first connecting body 42 is rotated, if the extending direction of the protrusion 45 is not inclined with respect to the rotation axis L2 of the first connecting body 42 as shown in the drawing (if they match each other), the front wheel Even if WF is steered in either the right or left direction and the first connecting body 42 is rotated in either direction, the first connecting body 42 and the second connecting body 4
The protrusion 45 is not pushed and the operating rod 30 does not move in any direction only by rotating the three and the bush 44 integrally around the axis L2. Therefore, at this time, the front wheel WF
The rear wheel WR is not steered even if is steered.

Further, the actuating rod 30 is rotated by 90 degrees from the illustrated position to the one side by the driving means 50, and when the first connecting body 42 is rotated, the extending direction of the projection 45 is the rotation axis L2 of the first connecting body 42. On the other hand, if it is inclined 90 degrees toward the front of the vehicle,
As the front wheel WF is steered to the right (or left), the projection 45 is formed in the second connecting body along with the rotation in the counterclockwise direction (or the clockwise direction) when viewed from above the first connecting body 42. It is pushed leftward (or rightward) via 43 and the bush 44, and the actuating rod 30 is moved leftward (or rightward) in the direction of its axis L1. This movement of the operating rod 30 is transmitted to the relay rod 71 via the spring 31 and the like, and also causes the operation of the power cylinder mechanism C, so that the rear wheel WR is assisted by the power cylinder mechanism C and steered to the right (or left). It That is, the steering directions of the rear wheels WR and the front wheels WF are in phase. In the above operation, when the protrusion 45 is pushed through the bush 44, the bush 44 slides on the protrusion 45 in the extending direction while tilting with respect to the second connecting body 43. The above operation is performed when the first connecting body 42 rotates.
If the extending direction of 45 is inclined forward of the vehicle with respect to the rotation axis L2 of the first coupling body 42, the steering angle ratio of the rear wheel WR to the front wheel WF may be different, but the same can be obtained (rear). Wheel WR front wheel WF
The steering angle ratio with respect to is maximum when the extending direction of the projection 45 is inclined 90 degrees toward the front of the vehicle with respect to the rotation axis L2 of the first coupling body 42).

Further, the operating rod 30 is rotated 90 degrees from the illustrated position to the other side by the driving means 50, and when the first connecting body 42 is rotated, the extending direction of the projection 45 is the rotation axis L2 of the first connecting body 42. On the other hand, if it is tilted 90 degrees toward the rear of the vehicle,
With the rotation of the first connecting body 42 brought about by steering the front wheel WF to the right (or left), the protrusion 45 passes through the second connecting body 43 and the bush 44 to the right (or left). ), The operating rod 31 is moved to the right (or left) in the direction of the axis L1. This movement of the operating rod 30 is also transmitted to the relay rod 71 via the spring 31 and the like in the same manner as described above, and also causes the operation of the power cylinder mechanism C, so that the rear wheel WR is assisted by the power cylinder mechanism C and leftward (or Steer to the right). That is, the steering direction of the rear wheels WR with respect to the front wheels WF is in the opposite phase. In the above operation, when the protrusion 45 is pushed through the bush 44, the bush 44 slides on the protrusion 45 in the extending direction while tilting with respect to the second connecting body 43. If the extending direction of the protrusion 45 is inclined rearward of the vehicle with respect to the rotation axis L2 of the first connecting body 42 during the rotation of the first connecting body 42, the above operation is performed if the front wheel WF of the rear wheel WR. However, the steering angle ratio of the rear wheel WR to the front wheel WF is the same as the steering angle ratio of the rear wheel WR to the front wheel WF. Maximum when tilted toward 90 degrees).

By the way, in the present embodiment, the actuating rod 30 is rotated around its axis L1 by the drive means 50 controlled according to the vehicle speed, and the projection 45, the bush 44 and the second connecting body 43 are moved relative to the first connecting body 42. By the rotation of the first connecting body 42, the extending direction of the protrusion 45 with respect to the rotation axis L2 of the first connecting body 42 changes, so that the steering angle ratio and the steering direction of the rear wheel WR with respect to the front wheel WF depend on the vehicle speed. Change appropriately. Further, in the present embodiment, the actuating rod 30 is rotated about its axis L1 by the drive means 50 to change the steering angle ratio and the steering direction of the rear wheel WR with respect to the front wheel WF. When 42 is in the neutral state (straightening state) as shown in FIG. 1, the operating rod 30 does not move in the direction of the axis L1 thereof, so that the alignment of the rear wheels WR does not change at all and the steering stability is not impaired at all.

Further, in the present embodiment, the control valve C1 for controlling the supply / discharge of the pressure oil to / from the power cylinder C2 is provided coaxially and integrally with a part of the relay rod 71 which also serves as the piston rod of the power cylinder C2, that is, the first rod 71A. Valve spool formed on 7
1a1 and a valve sleeve 30b integrally formed on the outer periphery of the valve spool 71a1 coaxially and slidably in the axial direction and integrally formed with an operating rod 30 that moves in the axial direction according to the operation of the steering wheel WS. Since it is configured, the control valve C1 can be configured coaxially and compactly with respect to the power cylinder C2, and thus the power steering mechanism C can be downsized. Further, since the power cylinder C2 and the control valve C1 are connected through the oil passages (each through hole 71a7, 71a9, 71c2, 71c3, 71c4) provided in the relay rod 71, no piping is required, resulting in cost reduction and compact size of the power steering mechanism C. Can be realized.

Further, in the present embodiment, the operating rod 30 which integrally has the valve sleeve 30b and is coaxially and slidably mounted in the axial direction on the outer periphery of the valve spool 71a1 operates in accordance with the operation of the steering wheel. Since the valve spool is configured to be moved in the direction, the valve spool coaxially assembled in the valve sleeve can be configured to be simpler and more compact than the configuration in which the valve spool is axially moved according to the operation of the steering wheel. .

Further, in this embodiment, since the power steering mechanism C is arranged on the rear wheel WR side of the coupling mechanism A, when the relay rod 71 is pushed in the axial direction by the external force from the rear wheel WR, the control valve C1 is operated. The power cylinder C2 is operated so as to generate a force that opposes the external force. Therefore, the external force is canceled and the rear wheel steering device is not operated by the external force.

FIG. 5 shows another embodiment of the present invention. In the embodiment, the relay rod 171 is a first rod 171A (the first rod 71A and the third rod 71C of the above embodiment are integrated. And is prevented from rotating by the width across flats provided at the left end of the drawing), the second rod 171B and the lock nut 171C. In addition, the control valve C1 is
The first spool 171a1 is integrally formed with the first rod 171A of the first rod 171A, and the valve sleeve 130A is fitted to the inner hole end of the operating rod 130 and is connected to the operating rod 130 by the pin 130B. Then, the control valve
The supply port 171a2 of C1 is a through hole 171 provided in the first rod 171A.
a3 and a through hole 171b1 provided in the second rod 171B communicate with the inflow port Hp provided in the housing H, and both discharge ports 13
0a1 and 130a2 are the outer circumference of the valve sleeve 130A and the operating rod 130
An annular passage formed between them and a communication groove 130a3 formed at the outer periphery of the end of the valve sleeve 130A communicate with the outflow port Hr formed in the housing H, and the port 171a4 on the left side in the drawing is a through hole provided in the first rod 171A. 171a5, 171a6 communicates with the oil chamber R1 on the left side of the power cylinder C2, and the port 171a7 on the right side of the diagram communicates with the oil chamber R2 on the right side of the power cylinder C2 through holes 171a8, 171a9 provided in the first rod 171A. is doing. Both through-holes 171a5 and 171a8 are provided by drilling from the end of the first rod 171A and then closing the end opening with a ball or the like.

Since other configurations are substantially the same as those of the above-described embodiment,
The description is omitted. Further, the operation of this embodiment is substantially the same as the operation of the above-mentioned embodiment, and therefore the description thereof will be omitted.

[Modification]

In each of the above-described embodiments, the present invention is applied to the power steering mechanism of the rear wheel steering device, but the present invention can be applied to the power steering mechanism of the front wheel steering device as well. Not limited.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view of a rear wheel steering system equipped with a power steering mechanism according to the present invention, FIG. 2 is a plan view of the same, and FIG. 3 is a partially cutaway side view taken along line III-III of FIG. FIG. 4 is a plan view schematically showing an example of a vehicle equipped with the rear wheel steering system shown in FIGS. 1 to 3, and FIG. 5 is a vertical sectional front view showing another embodiment of the present invention. is there. Explanation of code WR …… Rear wheel (wheel), WS …… Steering wheel, B
…… Steering link mechanism, C …… Power steering mechanism, C1 …… Control valve, C2 …… Power cylinder, 30,130 ……
Actuating rod, 30b, 130A …… Valve sleeve, 71,171 ……
Relay rod, 71a1,171a1 …… Valve spool, 71a7,7
1a9,71c2,71c3,71c4 ... through hole (oil passage), 171a5,171a6,17
1a8, 171a9 ... through holes (oil passages).

Continuation of the front page (56) Reference JP 54-15233 (JP, A) JP 60-199771 (JP, A) JP 60-61371 (JP, A) JP 60-193870 (JP , A) JP 62-37280 (JP, A) JP 53-69334 (JP, A) Actual opening 55-104577 (JP, U) Actual opening 54-115489 (JP, U) Actual opening 59-70875 (JP, U) Actual opening 55-119259 (JP, U) Actual opening 60-193870 (JP, U) Actual opening Sho 55-1009071 (JP, U) Actual public 54-9701 (JP, Y2)

Claims (1)

[Scope of utility model registration request] 1. A power cylinder using a part of a relay rod of a steering link mechanism as a piston rod for connecting left and right wheels steerably, and a valve spool coaxially and integrally formed with another part of the relay rod. And a valve sleeve which is coaxially and slidably mounted on the outer circumference of the valve spool and constitutes a control valve for controlling the supply and discharge of pressure oil to and from the power cylinder by the valve spool. A power steering device for a vehicle, comprising an actuating rod that moves in the axial direction according to an operation of a steering wheel, and an oil passage connecting the control valve and the power cylinder to the relay rod.