JPH02249768A - Connecting structure of parallel shafts - Google Patents

Abstract

PURPOSE:To prevent excessive stress from being applied, even when both shafts are placed in rough parallelism, by connecting a main drive shaft movable in an axial direction to a driven shaft parallelly arranged to the main this drive shaft through a connecting structure consisting of a turnable connecting unit and an elastic unit in a state to be connected in series to this connecting unit. CONSTITUTION:A front wheel steering power cylinder 14 of a four-wheel steering vehicle steers a front wheel through a tie rod 15 or the like swivelably connected to both ends of a piston rod 14b of the power cylinder 14, and interlocking to action of this power cylinder 14, a meter cylinder 19, parallelly arranged with the power cylinder 14, is operated. Right and left pressure chambers of the meter cylinder 19 are connected communicating with right and left pressure chambers of a rear wheel steering power cylinder. In this case, a bracket 36 is fixed to an end part of the piston rod 14b, while one end of an arm 37 is turnably connected to the point end of a piston rod 19b of the meter cylinder 19 through a bearing 38a. The other end of the arm 37 is connected to the bracket 36 through a shaft 40 and an elastic unit 41.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a connection structure for interlocking two shafts disposed in parallel, and particularly to a connection structure for interlocking two shafts arranged in parallel. This is to prevent excessive stress from being applied to these shafts and their related members even if they are not in use.

[Conventional technology]

As a conventional technique related to the present invention, for example, Japanese Patent Application Laid-Open No. 1983-1999. There is a rear wheel steering device for a vehicle disclosed in Japanese Patent No. 45266, which is a device that steers the rear wheels in conjunction with front wheel steering.

This conventional device has a structure in which the rack shaft of the front wheel steering system and the piston rod of the hydraulic cylinder are arranged parallel to each other and are connected by a connecting member, so that the front wheel steering system When the shaft moves in the axial direction, the piston rod of the hydraulic cylinder also moves in the same direction, causing pressure fluctuations in the hydraulic chamber of the hydraulic cylinder. A hydraulic cylinder was activated to steer the rear wheels.

[Problem to be solved by the invention]

However, in the conventional device described above, the rack axis of the front wheel steering system and the piston rod of the hydraulic cylinder are rigidly connected, so if the rack axis and the piston rod are not completely parallel, the rack axis Due to the movement of the rack shaft and piston rod, the relative position of the rack shaft and piston rod changes, which causes excessive stress to be applied to the members related to them, which impairs the durability of the seal members of the hydraulic cylinder, etc. The reliability of the entire device will be significantly reduced.

Such problems can be solved by arranging the rack shaft and the piston rod in a completely parallel state, but
Technically advanced (difficult) to improve parallelism
Since the manufacturing process is required, the manufacturing cost increases and the device becomes expensive, and it is impossible to completely eliminate manufacturing errors and assembly errors of each member.

This invention was made by paying attention to the unresolved problem of the conventional technology, and even if the two shafts are not completely parallel, it is possible to avoid excessive stress on these shafts and their related members. The purpose of the present invention is to provide a parallel shaft connection structure that does not apply excessive stress.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a connection structure of a main driving shaft movable in the axial direction and a driven shaft disposed parallel to the main driving shaft, the main driving shaft and the driven shaft A connecting body rotatable about a rotation axis that coincides with or parallel to these axes and an elastic body that is in series with the connecting body are used to connect the connecting bodies.

[Effect]

When the driving shaft moves in the axial direction, the driven shaft connected to the driving shaft via the connecting body and the elastic body also moves in the axial direction.

The connecting body can rotate about a rotation axis that is coincident with or parallel to the driving shaft and the driven shaft, and the elastic body that is in series with this connecting body can be deformed. Even if the parallelism is low and the relative position of both axes changes due to movement in the axial direction, the change is absorbed by the rotation of the connecting body and the deformation of the elastic body. Excessive stress will not be applied to supporting members, etc.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

1 to 3 show a first embodiment of the present invention,
In this embodiment, the present invention is applied to a four-wheel steering vehicle in which both the front wheels and the rear wheels are steered.

First, the overall configuration will be explained with reference to FIG. 3. 10a is a hydraulic pump driven by an engine (not shown);
0b is a reservoir tank, and these hydraulic pumps 10a
And between the reservoir tank 10b, one opposing connection point of a hydraulic bridge circuit 11 configured by connecting four flow paths in a bridge shape is connected.

Each of the four flow paths of the hydraulic bridge circuit 11 is provided with variable throttles IRlIL, 2R, and 2L whose throttle areas continuously change according to the steering torque generated when the operator operates the steering wheel 13. This hydraulic bridge circuit 11 and variable throttle IR, I
A control valve 1 that controls oil pressure supplied to a power cylinder for front wheel steering, which will be described later, by L, 2R, and 2L.
2 is configured.

That is, the variable apertures IR, IL, 2R, and 2L are changed by turning the steering wheel 13 to the left, for example, to change the variable apertures LL and 2L, and by steering the steering wheel 13 to the right, to the variable apertures I.
The two, R and 2R, are configured so that they are interlocked with each other, and the aperture area thereof changes in the direction of decreasing in accordance with the magnitude of the steering torque generated in the front wheel steering system.

The other opposing connection point of the hydraulic bridge circuit 11 is connected to the left and right pressure chambers 14L of the front wheel steering power cylinder 14.
, 14R, and this power cylinder 14 has a pressure chamber 14L.

A piston 14a that slides in accordance with the differential pressure between 14R and 14R is included. Further, a piston rod 14b having tie rods 15 swingably connected to both ends thereof is fixed to the piston 14a, and a knuckle arm 16 that rotatably supports the front wheel 17 is attached to the outer end of the tie rod 15. are connected via a ball joint.

On the other hand, a binion shaft (not shown) is integrally formed at the lower end of the steering shaft 13a that rotates together with the steering wheel 13, and a rack shaft (not shown) is formed integrally with the piston rod 14b in the steering gear box 18. are in mesh with each other, and these constitute a known rack and pinion steering gear.

Further, the steering gear box 18 includes a metering cylinder 1 parallel to the front wheel steering power cylinder 14.
9 is fixed, and a piston rod 19b fixed to a piston 19a that slides within this metering cylinder 19 is connected to the power cylinder 14 by a configuration described later.
The piston rod 14b is connected to the piston rod 14b, and is integrated in the forward and backward directions.

On the other hand, similarly to the front wheel steering system, the rear wheels 20 also have tie rods 2
The inner end of the tie rod 21 is rotatably supported by a knuckle arm 22 connected to the rear wheel steering power cylinder 23. movably connected.

In addition, the left and right pressure chambers 2 of the power cylinder 23 for rear wheel steering are
Each of 3L and 23R includes a center spring 23c that biases the piston 23a toward the neutral position, and if no differential pressure is generated between the left and right pressure chambers 23L and 23R, these Center spring 23c
The rear wheels 20 maintain a straight traveling state due to the urging force.

The left pressure chamber 19L of the metering cylinder 19 and the left pressure chamber 23L of the rear wheel steering power cylinder 23 communicate with each other via the oil passage 25a, and the right pressure chamber 19R of the metering cylinder 19 and the rear wheel steering power cylinder 23 communicate with each other via the oil passage 25a. power cylinder 23
The left pressure chamber 23R is in communication with the left pressure chamber 23R via an oil passage 25b.

Further, in the oil passages 25a and 25b, an electromagnetic type is provided, in which a spool is moved by a control signal supplied from the control device 30, and the metering cylinder 19 and the rear wheel steering power cylinder 23 are brought into communication or non-communication. A switching valve 26 is interposed therein, and the control device 30 detects the vehicle speed when traveling at low speed (for example, less than 10!If/h) in response to a vehicle speed detection signal supplied from a vehicle speed sensor 31 that detects the vehicle speed. When in communication state (spool position same as in Figure 3), when running at high speed (for example,
10 kit/h or more), a control signal is supplied to the switching valve 26 to bring it into a non-communicating state (the spool position is different from that shown in FIG. 3).

FIG. 1 is an enlarged sectional view of the connecting portion between the piston rod 14b of the front wheel steering power cylinder 14 and the piston rod 19b of the metering cylinder 19. In this embodiment, one piston rod 14b is connected to the main drive shaft. , the other piston rod 19b corresponds to the driven shaft, respectively. Further, FIG. 2 is a left side view of FIG. 1.

That is, the inner end of the tie rod 15 is swingably connected to the end of the piston rod 14b of the power cylinder 14 via the tie rod inner socket 35, and the inner end of the tie rod 15 is swingably connected to the end of the piston rod 14b of the power cylinder 14. One end of a bracket 36 is fixed to the housing, and the outer end of the bracket 36 is located outside the dust boot 14C for the power cylinder 14.

On the other hand, the piston rod 19 of the metering cylinder 19
One end of an arm 37 is rotatably coupled to the tip of b via a bearing 38a. Note that one end of the arm 37 is fitted with a nut 39 that is screwed onto the tip of the piston rod 19b.
a and dust boot 19 for metering cylinder 19
Since the arm 37 is held between the fixing member 39b to which the end of the arm 37 is fixed, the arm 37 is integrated with the piston rod 19b in the axial direction.

Further, one end of a shaft 40 is rotatably attached to the other end of the arm 37 via a bearing 38b, and further, the other end of the bracket 36 is attached to the other end of the shaft 40.
It is fitted onto the outside with a rubber bushing 41 as an elastic body interposed therebetween.

The other end of the arm 37, the shaft 40, and the bracket 36
This means that the shaft 40 is formed by a ring member 42 that is externally fitted onto one end of the shaft 40, a nut 43a and a washer 43b that are screwed onto the other end of the shaft 40, and a cylindrical body 44 that is externally fitted onto the center of the shaft 40. They are integrated in the axial direction.

Note that the diameter of the washer 43a and the rubber bushing 41 of the cylindrical body 44 are
The side diameter is equal to or slightly smaller than the diameter of the rubber bushing 41. Rubber bushing 41 thus has a serial relationship to bracket 36 and shaft 40.

Here, bracket 36. Arm 37. Bearing 38a, 3
8b and the shaft 40 constitute a connecting body of the present invention.

Next, the operation of the above embodiment will be explained.

When the steering wheel 13 is steered, for example, in the clockwise direction, the piston rod 14b with which the steering shaft 13 engages moves to the left in FIG. The aperture area changes in the direction of reduction.

Then, the hydraulic pressure supplied from the hydraulic pump 10a is supplied to the right pressure chamber 14R of the front wheel steering power steering 14, and a pressure difference is generated between the left and right pressure chambers 14L and 14a, causing the piston 14a and the piston rod 14b to move to the right pressure chamber 14R. Since the steering wheel is biased to the left in FIG. 3, a steering assist torque is generated in the front wheel steering system in the steering direction of the steering wheel 13, making it possible to perform a light steering operation.

Furthermore, when the piston rod 14b of the power cylinder 14 moves to the left in FIG. 3, the forward and backward force is also transmitted to the piston rod 19b of the metering cylinder 19 via the above-mentioned coupling body, so that the piston 19a also moves to the left in FIG. Move to.

At this time, if the vehicle is running at a low speed, the control device 30 puts the switching valve 26 into communication, so that the metering cylinder 19 and the rear wheel steering power cylinder 23 are connected to the oil passage 25.
a and 25b.

Therefore, the piston 19a of the metering cylinder 19 moves to the left in FIG.
The internal pressure of the pressure chamber 23L rises, and the piston 23a is urged rightward in FIG. Note that the hydraulic oil in the right pressure chamber 23R of the power cylinder 23 flows through the oil passage 25.
Right pressure chamber 19R of metering cylinder 19 via b
supplied to

When the piston 23a of the power cylinder 23 is biased to the right in FIG. 3, the piston rod 23b also moves in the same direction, so the rear wheel 20.20 is , front wheel 17.17
The vehicle is steered to the left, which is in the opposite phase, improving the vehicle's turning performance.

On the other hand, if the vehicle is running at high speed, the control device 30
The switching valve 26 is placed in a non-communicating state to disconnect the metering cylinder 19 and the rear wheel steering power cylinder 23, and the left and right pressure chambers 19L and 19a of the metering cylinder 19 are communicated via the spool of the switching valve 26. However, the left and right pressure chambers 23L and 23a of the power cylinder 23 communicate with each other.

Therefore, since no pressure difference is generated between the left and right pressure chambers 23L and 23a of the power cylinder 23, the piston 23a is held in the neutral position by the biasing force of the center springs 23c and 23c, and the rear wheels 20° 20 are not driven straight. maintain.

Furthermore, in the above embodiment, since the piston rod 14b of the power cylinder 14 and the piston rod 19b of the metering cylinder 19 are connected in the above-described configuration, the following effects can be obtained. .

That is, if the parallelism of both piston rods 14b and 19b deviates even slightly, these rods 14b and 19b
(Normally, the moving distance of the rack shaft in a front wheel steering system is 1 between the left and right maximum steering angles.)
It is about 50mm. ) will change.

However, the change in the relative position between the rods 14b and 19b is caused by the elastic deformation of the rubber bush 41 and the piston rod 1.
9b and the rotation of the arm 37 about the shaft 40, no unnecessary stress is applied to other members.

That is, both piston rods 14b and 19b (i.e.
power cylinder 14 and metering cylinder 19)
Even if they cannot be arranged in a completely parallel state, excessive stress can be applied to each member of the power cylinder cylinder 4 and metering cylinder 19 (for example, the seal members of the pistons 14a and 19a, etc.) as the piston rod 14b moves back and forth. Since there are no additional steps, the power cylinder 14 and metering cylinder 19 can be easily installed without using high-precision (expensive) parts.
This prevents leakage and improves the durability and reliability of the entire device.

FIG. 4 shows a second embodiment of the present invention, and shows the first embodiment described above.
FIG. 2 is a sectional view of the same portion as FIG. 1 of the embodiment. In addition, the first
The same members and parts as in the embodiment are given the same reference numerals, and overlapping explanations will be omitted.

That is, in this second embodiment, the piston rods 14b and 19b are connected by - arms 50,
One end of the arm 50 is rotatably coupled to the piston rod 19b by a bearing 38a.

The other end of the arm 50 is rotatably coupled to the piston rod 14b by a bearing 38c, and the other end of the arm 50 is rotatably coupled to the piston rod 14b by a bearing 38c.
A cylinder 51 and a rubber bush 52 are inserted between the piston rod 13c and the piston rod 14b.

The other end of the arm 50 is held between nuts 53a and 53b that are screwed onto the piston rod 14b, so that the arm 50 and the piston rod 14b are integrated in the axial direction.

Therefore, the arm 50 and the rubber bush 52 are in a series relationship with respect to the component in the direction that intersects the piston rod 14b.

Here, the bearings 38a, 38c, the arm 50 and the cylindrical body 51
The connector of the present invention is constructed by:

Even with such a configuration, changes in the relative position between the piston rods 14b and 19b are absorbed by the elastic deformation of the rubber bush 52 and the rotation of the arm 50.
It is possible to obtain the same effects as in the first embodiment.

In each of the embodiments described above, the present invention is applied to a steering system of a vehicle, but the present invention is not limited to this, and can of course be applied to other fields.

Furthermore, the connecting body of the present invention is not limited to the configurations of the first and second embodiments described above. For example, another bracket may be fixed to the piston rod 19b side, and the first The lower end of the drawing may be connected to be rotatable about a rotation axis parallel to the piston rod 19b. In short, it is sufficient that the connecting body is rotatable with a rotation axis that is coincident with or parallel to the driving and driven axes. However, although three or more rotation axes may be provided, two is optimal in terms of cost and durability.

〔Effect of the invention〕

As explained above, according to the present invention, the driving shaft movable in the axial direction and the driven shaft disposed parallel to the driving shaft can be moved between the driving shaft, which is movable in the axial direction, and the driven shaft which is arranged parallel to the driving shaft. Since the connection is made by a connecting body that can rotate around the shaft and an elastic body that is in series with this connecting body, the main drive shaft can move forward and backward even if the two wheels cannot be arranged in a completely parallel state. Since excessive stress is not applied to these shafts and related components, it is possible to improve the durability, durability, and reliability of the entire device without using high-precision (expensive) components. There is an effect that it can be done.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the main parts of the first embodiment of the present invention, FIG. 2 is a left side view of FIG. 1, FIG. 3 is an overall configuration diagram of this embodiment, and FIG. FIG. 7 is a sectional view showing the main parts of a second embodiment of the invention. 13... Steering wheel, 14... Power cylinder for front wheel steering, 14b... Piston rod (main driving shaft), 15.21... Tie rod, 16.22...
Knuckle arm, 17...front wheel, 20...rear wheel, 1
9... Metering cylinder, 19b... Piston rod (driven shaft), 23... Power cylinder for rear wheel steering, 35... Tie rod inner socket, 36...
Bracket, 37...Arm, 38a, 38b, 3
8cm... Bearing, 39a, 43a... Nut, 40.
...Shaft, 41...Rubber bushing (elastic body), 4
4... Cylindrical body, 50... Arm, 52... Rubber bush (elastic body).

Claims (1)

[Claims] (1) A connection structure of a driving shaft movable in the axial direction and a driven shaft arranged parallel to the driving shaft, the driving shaft and the driven shaft being aligned or parallel to these axes. 1. A connecting structure for parallel shafts, characterized in that the connecting body is rotatable about a rotational axis, and the connecting body is connected to an elastic body that is in series with the connecting body.