JPH03182876A - Power steering device - Google Patents

Abstract

PURPOSE:To easily secure a space for a hydraulic pump by integrally providing a pump housing containing the hydraulic pump for a housing containing a hydraulic control valve and the like in parallel, and thereby communicating both of the housings with each other through an oil port. CONSTITUTION:A rack shaft 1 is pivotally supported in a cylindrical housing in such a way as to be freely slidable, and a pinion 30 on a pinion shaft 3 is meshed with the rack shaft 1. The pinion shaft 3 is so connected to an input shaft 2 via a torsion bar 4 as to be formed into a connecting section between both of the shafts 2 and 3 so that feed oil pressure to a power cylinder S is thereby controlled. A hydraulic control valve 5 is provided, which loosely engages a spool 51 within a valve body 50. In this case, a hydraulic pump 6 is housed in a pump housing 7 which is integrally provided for the outside of a housing 13 in parallel. A discharge chamber 64 which is communicated with a pump chamber through a discharge hole 66, is then communicated with a specified position on the outer circumference of the valve body 50 through an oil port 70 which penetrates through a boundary wall between both of the housings 7 and 13.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an extraction type power steering device that provides steering assistance using the force generated by a hydraulic actuator disposed in a steering mechanism.

[Prior art]

Hydraulic power steering devices, which use hydraulic pressure to supplement the force required to operate the steering wheel, have been popularized in recent years as a means of achieving a comfortable steering sensation.

They are now widely used not only in large vehicles such as buses, but also in regular passenger cars. This power steering device has a hydraulic actuator such as a power cylinder that generates steering assist force arranged in the steering mechanism, and a hydraulic pump that is a hydraulic pressure generation source that supplies hydraulic pressure to the hydraulic actuator. The structure is equipped with a hydraulic control valve that is controlled according to steering wheel operation. This hydraulic control valve is configured integrally with the shaft body inside the housing of the shaft body connected to the steering wheel, and is configured to perform a hydraulic control operation in response to rotation of the shaft body associated with steering wheel operation. .

[Problem to be solved by the invention]

Now, the hydraulic pump is driven by an engine when fishing on a boat, but in this case, the installation position of the hydraulic pump is limited to the vicinity of the engine, so the hydraulic pressure is required to guide the generated hydraulic pressure to the hydraulic control valve. When driving on a mountain road, etc., where the piping is forced to be long and the temperature of the hydraulic oil increases due to the resistance when flowing through the piping, and the steering wheel is continuously operated, it is necessary to provide a designated steering assistance. The problem was that it was difficult to obtain power and the steering sensation deteriorated. In addition, in small special vehicles, it is extremely difficult to route the hydraulic piping in the narrow engine room, and it is also difficult to secure a space for installing the hydraulic pump near the engine.

For example, as disclosed in Japanese Unexamined Patent Publication No. 56-99859, when an electric type is used as the hydraulic pump, the mounting position thereof is not limited to the vicinity of the engine, but even in this case, the hydraulic pump and Installation space for this drive motor must be secured in the engine room, and if this installation cannot be done near the hydraulic pressure control valve, the difficulty in routing the hydraulic piping to the extraction pressure control valve remains unresolved.

The present invention was made in view of the above circumstances, and eliminates the need for hydraulic piping between the hydraulic pump and the hydraulic control valve, eliminating the difficulty in routing the piping, and significantly reducing the temperature rise of the hydraulic fluid. The purpose of the present invention is to provide a power steering device that can suppress the

[Means to solve the problem]

The power steering device according to the present invention includes a shaft body connected to a steering wheel, and a shaft body connected to a steering wheel, and a shaft body between a hydraulic actuator that generates a steering assist force and an electric hydraulic pump that generates operating hydraulic pressure for the hydraulic actuator. A power steering system that includes an integrally configured hydraulic control valve, and controls the hydraulic pressure supplied to the hydraulic actuator according to the rotation of the shaft body associated with steering wheel operation through the operation of the hydraulic control valve. In the apparatus, a pump housing is integrally arranged in parallel on the outside of the housing and has the hydraulic pump configured therein, and the pump housing and the housing are connected to each other at a predetermined position. It is characterized by having an oil guide hole communicating therewith.

[Effect]

In the present invention, an electric hydraulic pump that generates operating hydraulic pressure is configured in a pump housing that is integrally arranged in parallel with the outside of a housing that includes a hydraulic control valve therein. The hydraulic pressure generated by the pump is guided to a hydraulic control valve through an oil guide hole that communicates between the insides of both housings, and is supplied to a hydraulic actuator in accordance with the operation of the hydraulic control valve.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on drawings showing embodiments thereof. FIG. 1 is a partially broken pressure surface view showing the main parts of the power steering device according to the present invention, and FIG. 2 is a longitudinal cross-sectional view taken along the line ■-■ in FIG. 1.

These figures show examples of a rack-binion type steering mechanism. In the figure, l denotes a rack shaft, which is supported slidably in the axial direction inside a cylindrical rank housing IO fixed to the front of the vehicle body. The protruding ends of the rack shaft l from the openings at both ends of the rank housing 10 are connected to tie rods 12 connected to left and right front wheels (not shown), respectively.
．． 12 via respective separate ball joints 11.11. A cylindrical housing 3 is provided in the vicinity of one end of the rank housing IO in a diagonal manner, and as shown in FIG. An input shaft 2 is supported on the lower side, and a pinion shaft 3 having a pinion 30 in the middle thereof is supported rotatably on the same axis -h. Input shaft 2 and pinion shaft 3
are connected to each other via a 1-version bar 4 inserted into the hollow part of the input shaft 2, and the pinion 30 in the middle of the pinion shaft 3 is connected to the housing 13 and the rank housing 10.
It meshes with the rank shaft 5 at the intersection. The upper end of the input shaft 2 protruding outside the housing 13 is connected to the first
As shown by the two-dot chain line in the figure, it is connected to a steering wheel (steering wheel) 20, and when the steering wheel 20 is rotated, this rotation is applied to the pinion shaft 3 via the input shaft 2 and torsion bar 4. After being transmitted and converted into sliding motion in the axial direction of the rack shaft 5 meshing with the pinion 30, the ball joint 11.
The power is transmitted to the left and right front wheels through the steering wheels 11 and 12 and 12, respectively, and these wheels change direction to perform steering.

The power cylinder S for assisting with this steering includes a disk-shaped piston plate 15 fixed to the middle of the rack shaft 1 in a cylinder chamber 14 formed over a predetermined length inside the rank housing 10. A pair of oil chambers are slidably fitted inside the piston plate 15 and sealed in a liquid-tight manner on both sides of the piston plate 15. It is configured to press the rack shaft 1 and assist the sliding movement of the rack shaft 1, that is, the steering operation.

A hydraulic control valve 5 that controls the hydraulic pressure supplied to the power cylinder S according to the steering operation is configured at a connecting portion between the human power shaft 2 and the piston shaft 3 inside the housing 13,
A cylindrical valve body 50 rotatably fitted into the housing 13 is connected to the upper end of the pinion shaft 3 while restricting its rotation. A spool 51 integrally formed with the half part is loosely fitted coaxially rotatably. As mentioned above, the human power shaft 2 and the pinion shaft 3 are connected via the 1-version bar 4, and when the steering wheel 20 is rotated, the torsion bar 4 is twisted due to this, and the human power shaft 2 and Spool 5 between pinion 3 and integrated with these
1 and the valve body 50, a relative angular displacement occurs between the steering wheel 20 and the valve body 50, which corresponds to the direction and magnitude of the steering torque applied to the human power shaft 2 as the steering wheel 20 is operated.

The hydraulic control valve 5 controls the hydraulic pressure supplied to the power cylinder S using this relative angular displacement, and is used to control the hydraulic pressure supplied to the power cylinder S, the hydraulic pump 6 that generates the operating hydraulic pressure for the power cylinder S, and the hydraulic pump 6 for discharging oil. It is interposed between the oil tank T and the oil tank T.

Now, in the power steering device according to the present invention, the hydraulic pump 6 is an electric type, and is mounted on the outside of the housing 13 surrounding the hydraulic control valve 5 configured at the connecting portion between the human power shaft 2 and the pinion shaft 3. It is characterized in that it is configured inside a pump housing 7 that is arranged in parallel with the pump housing 7.

FIG. 3 is a sectional view taken along the line n+-m in FIG. 2. As shown in this figure and FIG. The hydraulic pump 6 is provided in a large diameter portion in the lower half of this cavity. Further, a motor 8 for driving the hydraulic pump 6 is fixed to the upper end of the pump housing 7, and an output shaft 80 of the motor 8 projects above the axis of the large diameter portion.

The illustrated hydraulic pump 6 has a plurality of rectangular flat vanes,
The short cylindrical rotor 60 is equally spaced in the circumferential direction,
This is a known vane pump in which an annular shape with uneven thickness is housed coaxially in a cam ring 61, and a pump chamber is formed between a plurality of recesses equally distributed on the inner periphery of the cam ring 61 and the outer periphery of a rotary wheel 0. be. The cavity of the pump housing 7 includes:
A cam ring 61, in which the rotor 60 is coaxially housed, and a thick disk-shaped pressure plate 62 are fitted in this order from the lower opening, and the rotor 60 protrudes into the cavity. The output shaft 80 of the motor 8 is spline-coupled. Further, a lid plate 63 that closes the lower opening of the cavity is fitted with a stopper to prevent it from being pulled out from the opening, and there is a gap between the lid plate 63 and the pressure plate 62. A coil spring 69 is interposed therebetween to bias the two in a direction away from each other. With the above configuration, the cam ring 61 is clamped and fixed between the end face of the large diameter part of the cavity and the pressure plate 1 62 by the biasing force of the coil spring 69, and responds to the rotation of the motor 8. The rotation of the rotor 60 generated inside the cam ring 61 as a lever causes a pumping action to occur in a plurality of pump chambers formed between the rotary wheel 0 and the cam ring 61. The hydraulic pump 6 has a discharge chamber 6 between a pressure plate 62 and a cover plate 63.
4 and a suction chamber 65 between the inner periphery of the cavity of the pump housing 7 and the outer periphery of the cam ring 61, and the discharge chamber 64 has a discharge hole 66 (see FIG. ), the suction chamber 65 has a suction hole 67 (
(see FIG. 3) to communicate with the pump chambers. The suction chamber 65 also includes a suction oil passage 71 formed in the pump housing 7 . It is connected to the oil tank T via a suction pipe 72 fixed to the open end of the suction oil passage 71, and a discharge chamber 64 is formed by penetrating the boundary wall between the pump housing 7 and the housing 13. The oil guide hole 70 communicates with a predetermined position on the outer periphery of the valve body 50 of the hydraulic control valve 5 configured within the housing 13.

With the above configuration, by energizing the motor 8, the hydraulic pump 6
is driven, the hydraulic oil in the oil tank T flows through the suction pipe 72.
The oil is introduced into the suction chamber 65 through the suction oil 1iB71, is sucked into each pump chamber through the suction hole 67, is pressurized by the rotation of the rotor 60, and then flows through the discharge hole 66 into the discharge chamber 64.
The oil is discharged into the housing 13 through the oil guide hole 70, and the hydraulic control valve 5 configured in the housing 13
will be sent to In this way, in the power steering system according to the present invention, the hydraulic pump 6 is configured in the pump housing 7 that is arranged in parallel on the outside of the housing 13 that houses the hydraulic control valve 5. Since the driving motor 8 is located along the housing 13 as shown in the figure, the housing 1
It is only necessary to secure a small space around 3, and there is no difficulty in securing the installation position of the hydraulic pump as in the conventional case. Furthermore, by forming the oil guide hole 70 that communicates the pump housing 7 and the housing 13, the oil discharged from the hydraulic pump 6 can be fed to the hydraulic control valve 5, which eliminates the conventionally required length for this feeding. This eliminates the need for long hydraulic piping, eliminates difficulties in routing the piping, and suppresses temperature rises in the hydraulic oil caused by piping resistance.

The oil discharged from the hydraulic pump 6 that is supplied to the hydraulic control valve 5 is transferred to a pair of cylinder boats 16 that open to the outside of the housing 13 by the operation of the hydraulic control valve 5 that occurs as described above in response to the operation of the steering wheel 20. .17, for example, cylinder boat 1
6 to one oil chamber of the power cylinder S, and generates a steering assist force in a direction corresponding to the operating direction of the steering wheel 20. At this time, the hydraulic oil in the other oil chamber of the power cylinder S is pushed out as the piston plate 15 slides, and is returned to the hydraulic control valve 5 via the other cylinder boat 17.
Furthermore, the hydraulic pump 6 is guided through the hollow part of the input shaft 2 to a reflux chamber 18 formed above the hydraulic control valve 5, and is refluxed to the oil tank T via a tank boat 19 that opens into the reflux chamber 18. Since it is electric, as shown in Figure 1,
A DC motor is used as the drive motor 8 of the hydraulic pump 6, and an energization control unit 21 that controls the current flowing through the motor 8.
The rotational speed of the hydraulic pump 6 can be changed by the operation of the energization control section 2, and the hydraulic pressure generated by the hydraulic pump 6 can be freely set. For example, if the value of the vehicle speed detected by the vehicle speed sensor 22 is given to the energization control unit 21 and the current applied to the motor 8 is changed from large to small according to the slowing of the vehicle speed, the hydraulic pressure generated by the hydraulic pump 6 is changed depending on the slowing of the vehicle speed. The steering assist force generated by the power cylinder S by supplying this hydraulic pressure can be increased when traveling at low speeds and decreased when traveling at high speeds. As a result, when driving at low speeds, when operating the steering wheel 20 for steering requires a large amount of force, the power cylinder S generates a large steering assist force that provides a light steering feeling, while when driving at high speeds, The steering assist force generated by the power cylinder S is small, and appropriate rigidity is imparted to the steering wheel 20. As a result, steering is not performed due to a slight force applied to the steering wheel 20, and a decrease in driving stability is eliminated. Ru. Furthermore, in addition to the detection results of the vehicle speed sensor 22, the detection results of various sensors for detecting the running state, such as a steering angle sensor and an acceleration sensor, are provided to the energization control unit 21, and based on these, the detection results are sent to the motor 8. If the configuration is such that the energizing current is controlled, an appropriate steering assist force can be obtained depending on the driving condition, and a comfortable steering feeling can be realized.

FIG. 4 is a longitudinal sectional view showing another embodiment of the power steering device according to the present invention. In this figure, the recirculation chamber 18 above the hydraulic control valve 5 is communicated with the suction chamber 65 of the hydraulic pump 6 through an oil guide hole 73 penetrating the partition between the housing 13 and the pump housing 7.

That is, with this configuration, the recirculation oil from the power cylinder S is guided into the recirculation chamber 1B as described above, and then passes through the oil guide hole 7.
3 and is directly introduced into the suction chamber 65,
As the oil tank T shown in FIG. 2 is not required, the piping from the hydraulic control valve 5 to the oil tank T and the piping from the oil tank T to the hydraulic pump 6 can also be omitted. However, in this case, in order to suppress the rise in temperature of the hydraulic oil, a yuzu reservoir 9 communicating with the suction chamber 65 is provided at the fixed position of the suction pipe 72 in FIGS. 2 and 3. This oil reservoir 9 functions as an oil tank by loading yuzu from a cap 91 equipped with a level gauge.

In this embodiment, the pump housing 7 that constitutes the hydraulic pump 6 therein is arranged substantially parallel to the housing 13 of the hydraulic control valve 5, but both housings 1
The juxtaposition mode of Nos. 3 and 7 is not limited to this.

Further, the hydraulic pump 6 is not limited to the Hoehn pump in this embodiment, but may be other types of hydraulic pumps such as a trochoid pump or a gear pump.

〔effect〕

As described in detail above, in the power steering system according to the present invention, an electric hydraulic pump that generates operating hydraulic pressure for the power cylinder is arranged integrally on the outside of the housing, which includes a hydraulic control valve therein. The hydraulic pump is configured in a pump housing, which makes it easy to secure a space for installing the hydraulic pump, and also connects the hydraulic pressure generated by the hydraulic pump to the hydraulic control valve via an oil guide hole that communicates the inside of both housings. This eliminates the need for the long hydraulic piping that was previously required, eliminating the difficulty of routing the piping, and suppressing the rise in temperature of the hydraulic fluid caused by piping resistance, making it easier to operate the steering wheel. The present invention has excellent effects, such as suppressing deterioration of steering feeling during continuous mountain road driving.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway front view showing the main parts of the power steering device according to the present invention, FIG. 2 is a longitudinal sectional view taken along line m-n in FIG. 1,
FIG. 3 is a longitudinal sectional view taken along the line ■--■ in FIG. 2, and FIG. 4 is a longitudinal sectional view of a main part showing another embodiment of the power steering device according to the present invention. 2... Input shaft 3... Pinion shaft 5... Hydraulic control valve 6... Hydraulic pump 7... Pump housing 8... Motor 13... Housing 50... Pulp body 51...・Spool 60...Rocro 1...Cam ring 64・
...Discharge chamber 65...Suction chamber 5 071 ...Oil guide hole S...Power cylinder patent Applicant Koyo Seiko Co., Ltd.

Claims (1)

[Scope of Claims] 1. Between the hydraulic actuator that generates steering assist force and the electric hydraulic pump that generates the operating hydraulic pressure, there is a housing that is integral with the shaft that is connected to the steering wheel. In the power steering device, a hydraulic control valve configured as shown in FIG. , a pump housing that is integrally arranged in parallel on the outside of the housing and has the hydraulic pump configured therein; and a conductor that communicates the insides of both at a predetermined position between the pump housing and the housing. A power steering device characterized by comprising an oil hole.