JPS582101B2 - Power steering device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power steering device, in which a control valve mechanism for controlling the supply and discharge of pressure oil from an oil pump to and from a power cylinder by switching a hydraulic circuit is installed at a position off the axis of a steering wheel shaft. By doing so, the axial length can be shortened.

In conventional power steering devices, the control valve mechanism usually needs to be placed on the same axis as the steering wheel shaft.
The overall length was longer than that of the manual steering gear.

Therefore, as power steering devices have been adopted in small vehicles in recent years, it has become difficult to install conventional power steering devices, which have a long overall length, on small vehicles because of the installation space, especially the installation space in the axial direction. The disadvantage was that it was difficult.

In view of these points, the present invention makes it possible to install the control valve mechanism at a position off the steering wheel axis, thereby reducing the overall length to approximately the entire length of a manual steering gear. To provide a power steering device that can be easily installed.

The present invention will be described in detail below with reference to the illustrated embodiment. In FIG. 1, 1 is a power steering device, 2 is a steering handle connected to the input shaft of this power steering device,
When the rotation is operated, the rotation is transmitted through the input shaft, the output shaft linked to this, and the pinion formed on this output shaft.
Furthermore, this linear motion is transmitted to the steering wheels 4, through links connected to both ends of the rack 3, etc.
4' as a rocking motion, and its steering wheels 4, 4'
to deflect.

At the same time, the control valve mechanism 5 converts the relative rotational displacement due to torsion between the input shaft and the output shaft into a linear displacement and transmits it to the spool valve, and the displacement of the spool valve causes the fluid pressure supplied from the oil pump 6 to be steering wheel 2
The power cylinder 7 is supplied and discharged according to the operating direction of the rack 3, and pressure oil is applied to the piston 8 fixed to the rack 3 in the power cylinder 7 to assist the rack 3 in deflecting the steered wheels 4, 4'. do.

However, in FIG. 2, the power steering device 1 includes the input shaft 9, the output shaft 10, the pinion 11 formed on the output shaft, and the rack 3 meshed with the pinion, as described above, and the input shaft 9 and the output shaft are connected to each other. The rack 3 is disposed on the same axis as the shaft 10 and rotatably supported within the housing 12, and the rack 3 is slidably disposed in a direction perpendicular to these axes.

The input shaft 9 and the output shaft 10 are connected to each other via a torsion bar 13, and the torsion of the torsion bar 13 allows the shafts 9 and 10 to rotate relative to each other.

Identical external gears 14 and 15 are integrally formed near the connection between the input shaft 9 and the output shaft 10, and each external gear 14
．． 15 are meshed with identical internal gears 16 and 17, respectively.

These internally toothed shafts 16 and 17 each have an annular bearing member 18
．． One bearing member 19 is fixed within the housing 12, while the other bearing member 18 has a pin 20 protruding from its end face attached to the housing 1.
By engaging in a hole 21 formed in 2, it is possible to swing around the pin 20.

As clearly shown in FIG. 4, a pair of protrusions 22, 23 are formed on the mutually opposing end surfaces of each internal gear 16, 17 to protrude on a straight line passing through the center of each internal gear 16, 17. At the same time, grooves 25 and 26 that engage with the pair of protrusions 22 and 23 are carved at mutually orthogonal positions on both end surfaces of the ring 24 interposed between the two internal gears 16 and 17, and The internal gears 16, 17 and the ring 24 are
As shown in the figure, the projections 22, 23 and the grooves 25.
26.

That is, the internal gears 16 and 17 are interconnected via the Oldham joint, and as will be explained in detail later, when relative rotation occurs between the input shaft 9 and the output shaft 10, The bearing member 18 is swung about the pin 20 in accordance with the amount of relative rotational displacement.

Next, in FIG. 3, the control valve mechanism 5 is shown in the housing 1.
A Subur valve 27 is slidably inserted into the inside of the valve 2,
This spool valve 27 is similar to the conventionally known one,
The pressure oil being circulated from the oil pump 6 through the ports 28 and 29 is transferred to the port 30 and the pipe line 31 or to the port 3 depending on the left and right displacement of the spool valve 27.
2 and a conduit 33 to supply the power cylinder 7 to the power cylinder 7.

In this embodiment, the Subur valve 27 is disposed off the axes of the input and output shafts 9 and 10 so as to be slidable in a direction perpendicular thereto, and the bearing member 18
In order to transmit the rocking motion of the spool valve 27 to the spool valve 27 as a linear motion, a groove 35 is formed in the center of the spool valve 27 with a projection 34 projecting from the outer periphery of the bearing member 18 on the side opposite to the pin 20. It is engaged inside.

Further, the axial length of the spool valve 27 is made to match the width of the housing 12, and disc springs 37. 37' is stored.

Both disk springs 37, 37' have a disc 38 that abuts against the end face of the spool valve 27 and at the same time abuts against the end face of the housing 12 when the spool valve 27 is in the neutral position.
．． 38', the meshing portion between the external gear 14.15 and the internal gear 16.17 and the internal gear 16
．． Even if there is backlash at the engagement portion between the protrusion 22, 23 of the ring 24 and the groove 25, 26 of the ring 24, the spool valve 27 is reliably maintained at the neutral position.

With the above configuration, when the vehicle is traveling straight,
That is, when the input shaft 9 and the output shaft 10 are stationary and the relative rotational displacement between them is zero, the internal gears 16 and 17 that mesh with the external gears 14 and 15 formed on each shaft 9 and 10 also rotate. At rest, in this state, the internal gear 16.17 and the bearing member 18.19 supporting them are located on the same axis, and the protrusion 34 of the bearing member 18 and the groove 3 therein are located on the same axis.
The spool valve 27, which is interlocked via 5, is held in a neutral position.

Therefore, the pressure oil from the oil pump 6 is not introduced into one chamber of the power cylinder 7 but is circulated through the ports 28 and 29, allowing both vehicles to travel straight.

When the input shaft 9 is rotated by rotating the steering wheel 2 from this state, the output shaft 10 is linked to the steering wheels 4, 4' via the rack 3 and receives road resistance from the steering wheels. Therefore, the input shaft 9 is rotated relative to the output shaft 10 against the torsion bar 13.

Then, the internal gear 16 that meshes with the external gear 15 formed on the input shaft 9 tries to rotate with the rotation of the input shaft 9, but the other internal gear 16 that rotates integrally with this internal gear 16 via the Oldham joint Since the internal gear 17 is still meshing with the external gear 15 of the output shaft 10 which is in a stationary state, the internal gear 16 cannot rotate with the rotation of the input shaft 9, and as a result, the Oldham coupling Functionally, the internal gears 16, 17 move from a state where their respective axes were located on the same axis to parallel axes that are different from each other.

At this time, since the bearing member 19 that supports one internal gear 17 is fixed to the housing 12, the bearing member 18 that supports the other internal gear 16 swings in one direction about the pin 20. Accordingly, the spool valve 27, which is interlocked with the protrusion 34 of the bearing member 18 via the groove 35, is also displaced in one direction from its neutral position.

When the spool valve 27 is displaced from the neutral position, as is well known in the art, the hydraulic circuit is switched to supply pressure oil to one chamber of the power cylinder 7, and this pressure oil is applied to the piston 8 to steer the wheels by the rack 3. 4, 4' assists in deflection.

The output shaft 10 starts to rotate in the rotational direction of the input shaft 9 due to the force of the pressure oil acting on the rack 3 and the steering force transmitted from the input shaft 9 via the torsion bar 13. When the output shaft 10 starts to rotate at the same speed, the internal gears 16 and 17 forming the Oldham joint also start to rotate in the same direction and at the same speed within the respective bearing members 18 and 19.

However, during this time, the output shaft 10 is constantly receiving steering resistance from the road surface while the vehicle is turning, so it rotates at the same speed as the input shaft 9 while being rotationally displaced relative to the input shaft 9. The internal gear 16, bearing member 18, and spool valve 27 also maintain their displaced states and continue to supply pressure oil to the power cylinder 7.

During this time, the driver senses the torsional force of the torsion bar 13, which attempts to return the relative rotational displacement of the input and output shafts 9 and 10 to zero, as an operation reaction force.

In the above embodiment, the displacement of the internal gear 1.6 is extracted as the swinging of the bearing member 18 that supports it. If provided freely, the displacement of the internal gear 16 can be extracted as the forward and backward movement of the bearing member 18.

As described above, in the present invention, an external gear is integrally provided on each of the input shaft and the output shaft, an internal gear is meshed with each of these external gears, and the input and output shafts are surrounded between the two internal gears. The two internal gears are mutually interlocked via an Oldham coupling with a ring as a component, and one internal gear is mounted on a housing, and the other internal gear is mounted on a bearing member that can be slid or oscillated in the housing. Since it is supported by a shaft, and this bearing member is linked with the spool valve of the control valve mechanism, the control valve mechanism is installed at a position off the axis of the handle, and its overall length is reduced compared to conventional ones. In addition, the Oldham joints for operating the control valve mechanism are configured to surround the input and output shafts, so those Oldham joints and controls in the diametrical direction of the input and output shafts can be shortened. The amount of protrusion of the valve mechanism can be suppressed to a minimum, and the overall length and width of the power steering device can therefore be reduced to facilitate installation in a small vehicle.

[Brief explanation of the drawing]

The figures all show embodiments of the present invention, and Fig. 1 is a schematic plan view showing a state in which the power rudder slope device according to the present invention is mounted on a vehicle, and Fig. 2 is taken along the line ■-■ in Fig. 1. FIG. 3 is an enlarged longitudinal sectional view taken along the line ■--■ in FIG. 2, and FIG. 4 is an exploded perspective view showing the main parts. 1... Power steering device, 2... Steering handle, 4, 4'...
...Steering wheel, 5...Control valve mechanism, 6...Oil pump,
7...Power cylinder, 9...Input shaft, 10...Output shaft, 12...Housing, 14.15...External gear, 16.
17... Internal gear, 18... Bearing member, 24... Ring,
27...Spool valve.

Claims (1)

[Claims] 1. An input shaft linked to the steering wheel, an output shaft arranged on the same axis as the input shaft and linked to the steering wheels, and a hydraulic circuit that controls the supply and discharge of pressure oil from the oil pump to the power cylinder. In a power steering device equipped with a control valve mechanism, an external gear is integrally provided on each of the input shaft and the output shaft, and an internal gear is meshed with each of these external gears,
Both internal gears are interlocked via an Oldham coupling whose constituent members are rings surrounding the input and output shafts, and one internal gear is connected to the housing, and the other internal gear is connected to the housing by sliding displacement or oscillation. A power steering device characterized in that the power steering device is rotatably supported by bearing members provided to be dynamically displaceable, and the bearing members are interlocked with a spool valve of the control valve mechanism.