JPS6132847Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a control device for a power steering device, and in particular to a device for controlling an on-off valve that connects and shuts off communication between both chambers of a power cylinder of a power steering device in accordance with vehicle speed. The purpose of this is to make it possible to generate pressure according to vehicle speed with an extremely simple configuration by incorporating a pump into a speed detection section provided in the transmission.

In general, in automobiles equipped with a power steering device, in order to compensate for the problem that the steering wheel operation becomes too light when driving at high speed, for example, both chambers of the power cylinder of the power steering device are communicated with each other when driving at high speed. Measures have been taken to bypass the fluid to the low pressure side, thereby reducing the steering gain. Accordingly, this type of power steering device is equipped with an on-off valve that connects and shuts off communication between both chambers of the power cylinder depending on the vehicle speed.

In the present invention, the opening and closing of such an on-off valve is controlled by pressure generated by a pump incorporated in a speed detection section.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
Reference numeral 10 denotes a transmission case of an automobile equipped with a power steering device 40. An engine output shaft 11 connected to a propeller shaft is rotatably supported in this transmission case 10.
A helical drive gear 12 is engaged on the transmission case 10. A detection unit main body 13 is fitted into the transmission case 10, and one end of the main body 13 faces the inside of the transmission case 10, and a sleeve 14 is fitted into the opening of the main body 13.
A drive shaft 15 is rotatably supported on the drive gear 12, and a driven gear 16 meshing with the drive gear 12 is fixed to one end of the drive shaft 15. The other end of the drive shaft 15 is connected to a speedometer via a cable (not shown), thereby forming a known speed detection section 17.

A trochoid pump 18 for generating pressure according to the vehicle speed is integrally built into the speed detecting section 17. That is, a casing 20 that is eccentric by a predetermined amount with respect to the axis of the drive shaft 15 is formed in an opening at one end of the main body 13 . An outer rotor 21 having n internal teeth is rotatably fitted into the casing 20 between the side walls of the main body 13 and the sleeve 14 as shown in FIG.
- said drive shaft 15 comprising one external tooth;
An inner rotor 22, which is locked to the inner rotor 22, is housed therein. As shown in FIG. 3, a suction port 23 and a discharge port 24 are formed in the side wall of the sleeve 14, and the suction port 23 is connected to the sleeve 1 through a through hole 25.
The discharge port 24 is connected to a suction port 26 recessed in the lower outer circumference of the sleeve 14, and the discharge port 24 is communicated via a throttle hole 27 to a discharge port 28 recessed in the upper outer circumference of the sleeve 14. The suction port 26 is immersed in mission oil 29 housed in the mission case 10, and the mission oil 29 is used as hydraulic oil for the trochoid pump 18. When the drive shaft 15 is thereby driven to rotate, the transmission oil 29 is sucked in through the suction port 26 and discharged from the discharge port 24, but due to the throttling action of the throttle hole 27, the trochoid pump 18 is injected into the discharge port 24. Back pressure will be generated depending on the rotation speed. Note that 30 is a filter that covers the suction port 26 and the discharge port 28.

Meanwhile, a pressure port 31 is formed in the side wall of the main body 13 opposite to the discharge port 24, and this pressure port 31 is connected to a conduit 32 fixed to the main body 13.
is communicated with. The conduit 32 is the power steering device 40
The control port 35 of the on-off valve 34 which communicates and shuts off both chambers of the power cylinder 33 is communicated via an introduction path 36. Valve housing 3 of such on-off valve 34
A spool valve 38 is slidably fitted in 7, and this spool valve 38 is normally held at the sliding end by the force of a spring 39. Valve housing 37
are formed with communication ports 41 and 42 that connect to both chambers of the power cylinder 33, and these communication ports 41,
42 are closed at the sliding end of the spool valve 38, but are brought into communication with each other by sliding the spool valve 38 against the spring 39 by the pressure introduced from the control port 35. ing.

Since the device of the present invention is configured as described above, when the inner rotor 22 of the trochoid pump 18 is rotationally driven by the rotation of the engine output shaft 11 via the drive gear 12, the driven gear 16, and the drive shaft 15, the suction port Mission oil 29 is sucked into the suction port 23 from 26 through the filter 30, and pressure oil is discharged from the discharge port 24 into the mission case 10 through the throttle hole 27 and the discharge port 28. At this time, back pressure is generated in the discharge port 24 due to the throttling effect of the throttle hole 27, and this back pressure is guided from the pressure port 31 to the control port 35 of the on-off valve 34. Since this back pressure is proportional to the rotational speed of the trochoid pump 18, that is, the rotational speed of the engine output shaft 11, and the vehicle speed, the control port 3 is
The pressure introduced into the power cylinder 33 does not rise until it overcomes the spring 39, and both chambers of the power cylinder 33 are cut off. Therefore, normal power steering action can be performed.

However, when the vehicle speed reaches a predetermined speed or higher, the pressure introduced into the control port 35 increases, and this pressure causes the spool valve 38 to slide against the spring 39, thereby gradually opening the communication ports 41 and 42. Since both chambers of the power cylinder 33 are opened, both chambers of the power cylinder 33 are communicated with each other.

Therefore, when the vehicle is traveling at high speed, the steering gain is reduced, and the anxiety that the steering wheel operation becomes too light can be alleviated.

In particular, according to the present invention, a pump such as a trochoid pump is integrated into the speed detection section provided in the transmission, and a pressure corresponding to the vehicle speed is generated by the action of a restriction provided in the discharge system of this pump. As a result, the configuration is extremely simple, and by using transmission oil as the hydraulic fluid for the pump, a practically beneficial effect can be achieved in that piping and the like can be simplified or eliminated.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, and FIGS. 2 and 3 are sectional views taken along the - line and - line in FIG. 1. 10... Transmission case, 11...
Engine output shaft, 12... Drive gear, 13...
...Detection unit main body, 15...Drive shaft, 17
...Speed detection unit, 18...Pump, 23...Suction port, 24...Discharge port, 26...Suction port,
27... Throttle hole, 28... Discharge port, 29... Mission oil, 33... Power cylinder, 34...
...Opening/closing valve, 35...Control port, 38...Spool valve, 39...Spring, 40...Power steering device.

Claims (1)

[Scope of utility model registration request] It is equipped with an on-off valve that connects and shuts off both chambers of the power cylinder of the power steering device based on hydraulic pressure depending on the vehicle speed, and also has a speed detecting section provided in the transmission connected to the engine output shaft. A pump driven by the drive shaft of the detection part is incorporated, and the suction port of this pump is immersed in the transmission oil housed in the case of the transmission, so that the transmission oil is sucked by the rotation of the pump, A control device for a power steering system, comprising: a discharge port of the pump communicating with the inside of the transmission case via a throttle; and an introduction passage for guiding back pressure proportional to the vehicle speed generated at the discharge port to the on-off valve. .