JPS6354590B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power steering device for an automobile or the like.

Fig. 1 shows a schematic representation of a semi-integral type power steering device that is commonly used.

A gear box 3 containing a switching valve, a power cylinder, and a steering gear is connected to the input shaft 2 of the handle 1.

On the other hand, an oil pump 6 which is connected to the crankshaft 5 of the engine body 4 via a belt 9 and a pulley 10 is attached to the outer wall (cylinder block) of the engine body 4 via a pump bracket 7 together with a reservoir 8.

In order to supply high pressure from the oil pump 6 to the power cylinder inside the gearbox 3, these are connected by a high pressure hose 8A and a low pressure hose 8B.

That is, the high oil pressure generated by the oil pump 6 is sent to the power cylinder inside the gearbox 3 via the high pressure hose 8A, and the return oil is returned to the suction side of the oil pump 6 from the low pressure hose 8B.

A normal power steering device is constructed in this way, but in reality, the engine body 4 and the steering wheel input shaft 2 are quite far apart, so the piping such as the high and low pressure hoses 8A and 8B is narrow. The oil pump 6 is arranged in a complicated manner in the engine room, and the installation of the oil pump 6 is also subject to space constraints.
Another problem was that a large number of accessory parts such as the bracket 7 and tightening bolts were required for this installation.

The present invention has been devised to solve these problems.The oil pump, which is driven by an electric motor only when the handle is operated, is directly attached to the gearbox, reducing the number of piping and fittings, and reducing the power source. The purpose of the present invention is to provide a power steering device that saves energy.

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

As shown in FIG. 2, the input shaft 2 of the handle 21
A gear box 24, which includes a control valve 23, a power cylinder (not shown), and a steering gear, is connected to the tip of the gear box 2. Of course,
The input shaft 22 is screwed to the piston of the power cylinder via a torsion bar and a hole screw.
At the same time, it is connected to the input member of the control valve 23, and the control valve 23 is switched and operated according to the direction of rotation of the handle.

An oil pump 25 is integrally attached to a part of the gear box 24 in proximity to the control valve 23.

The oil pump 25 is a vane pump, and an electric motor 27 is coaxially connected to the pump shaft 26, and the rotation of the electric motor 27 drives the oil pump 25.

In this case, the housing 25 of the oil pump 25
It is preferable to directly fasten A and the housing 27A of the electric motor 27 so that no supporting load is applied to the pump shaft 26 or the like.

An oil reservoir (tank) 28 is also integrally bolted to the side of the oil pump 25 and is connected in communication to the pump suction port.

In other words, in this way, the oil pump 25 and the electric motor 27 are directly connected to the gearbox 24.
and an oil reservoir 28 are attached.

Note that 29A is a discharge port that connects the control valve 23 and the oil pump 25, and 29B is a return port.

On the other hand, there is an input shaft 22 in the middle of the input shaft 22.
As a means for detecting the rotation of the input shaft 22, a limit switch 30 is provided on the vehicle body as a means for detecting the rotation of the input shaft 22, as shown in FIG.
protruding from the outer periphery of the

Only when these limit switches 30 are activated (on), the electric motor 27 and the battery 33 are energized to drive the oil pump 25.

Next, the effect will be explained.

When the handle 21 is in the neutral position, that is, when the vehicle is traveling straight, the limit switch 30, which serves as a rotation detection means for the input shaft 22, fits into the groove 31A of the cam 31 and does not operate, so the electric motor 27 is not activated. Therefore, the oil pump 25
does not rotate and no pressure oil is sent to the control valve 23.

In conventional power steering devices, the oil pump is constantly rotating, but when the steering wheel is in the neutral position, pressure oil is returned via the control valve, meaning that there is no supply of pressure oil to the power cylinder. Therefore, even if the oil pump 25 stops operating as in the present invention, there is no functional problem.

When the handle 21 is rotated in either direction, the limit switch 30 immediately detects the rotation, energizes the electric motor 27, and drives the oil pump 25 to rotate. As a result, the control valve 23 is switched in accordance with the direction of rotation of the steering wheel, and pressure oil from the oil pump 25 is sent to a power cylinder (not shown), and the wheels are turned via the steering gear while being assisted by the pressure oil. It will be done.

By the way, the supply pressure oil is proportional to the rotation speed of the oil pump 25, but unlike the conventional vehicle engine which directly drives it, it is driven by an electric motor 27 that rotates at a constant speed, so the oil pump 25 is The discharge amount can be accurately controlled without providing a flow control valve.

Furthermore, if a potentiometer that produces an output proportional to the rotation angle is installed as a rotation detection means for the input shaft 22, and the electric motor 27 is variably rotated according to the control current value, the handle rotation The larger the angle, the oil pump 25
can increase the generated oil pressure or oil amount,
It transmits power assist according to the so-called steering load.

As explained above, according to the present invention, since the oil pump and electric motor are integrally attached to the gearbox, parts such as hydraulic piping and mounting brackets can be reduced, and an overall compact and low-cost system can be provided.

In addition, since the oil pump is driven only when the handle is operated via the electric motor, the energy of the power source is saved, and power loss in the high rotation range is significantly reduced compared to engine-driven systems. do.

Additionally, since the oil pump does not require a flow control valve, the structure can be simplified and costs can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional device. FIG. 2 is a sectional view of the present invention, and FIG. 3 is a sectional view taken along the line -- in FIG. 21...Handle, 22...Input shaft, 23...
Control valve, 24...Gearbox, 2
5... Oil pump, 27... Electric motor, 30
...Limit switch.

Claims (1)

[Claims] 1 A gearbox housing a power cylinder and a control valve inside is connected to the tip of the handle input shaft, and an oil pump directly connected to the electric motor is attached to this gearbox, while a means for detecting the rotation of the input shaft is provided. A power steering device characterized in that, depending on the value, power assist is provided by driving an oil pump via an electric motor only when a steering wheel is operated.