JPS643707B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a flow rate regulating valve used in power steering of an automobile.

In general, this type of power steering often takes the form of a servo mechanism included in a manual steering mechanism, in which manual steering displacement is given to the servo mechanism as an input signal, and the output mechanism It is configured to be able to operate by following the displacement of.

Moreover, most of the power sources for the output mechanisms are hydraulic type, and therefore, an oil pump is usually used as the power source for the output mechanisms.

The above-mentioned flow rate regulating valve controls the flow rate of pressure oil supplied from such an oil pump, and the rotation speed of the oil pump caused by the flow rate of the supplied pressure oil changes to the rotation speed of the internal combustion engine. In idling conditions, the specified flow rate is ensured, and when the internal combustion engine is running at high speeds, unnecessary excess flow is returned to the suction side of the oil pump to reduce steering rotation. It is constructed so that the operating force required for the operation can be maintained constant.

Furthermore, in recent years, in order to stabilize the steering when an automobile is traveling at high speed, there has been a trend to use a flow rate regulating valve to slightly increase the weight of the steering.

However, the flow rate of pressure oil controlled by such a flow rate regulating valve is set to obtain a predetermined flow rate depending on the rotational speed of the internal combustion engine, so when a car goes downhill with the engine When driving in a low gear while using the brakes or driving uphill with the engine running, the internal combustion engine is rotating at high speed, so the steering operation becomes heavy, especially when the steering operation is light and fast. In the case of a required slope with many curves, there was a risk that the steering operation would be hindered.

An object of the present invention is to provide a flow rate regulating valve used in power steering that can adjust the weight of the steering wheel according to the driving conditions of the vehicle and the road surface on which the vehicle is traveling, thereby reducing driver fatigue caused by steering operations. It is in.

In view of the above problem, the flow regulating valve used in the power steering of the present invention has an inlet side port connected to the discharge side of the oil pump, and a power steering valve.
A valve casing with an outlet port connected to the reaction control valve side of the steering device and a bypass port connected to the suction side of its oil pump;・A valve chamber formed in the valve casing in communication with the port, and the valve chamber formed in the valve casing in communication with the port.
an oil return control spool that is reciprocally slidable in the chamber and adjusts communication between the inlet port and the bypass port; a metering orifice formed in the throat of the ventilate, and a metering orifice connecting the metering orifice to an oil passage at its outlet port downstream of the valve chamber;
It is placed at the connection point between the bypass, the oil passage of the outlet side port downstream of the valve chamber, and the metering bypass, and switches the oil passage upstream and the metering bypass to the downstream of the oil passage. A pilot communication passage that cooperates with the connected switching valve and its oil return control spool to supply the metering bypass side pressure oil to the back pressure chamber formed in the valve chamber, and its back. and a return spring disposed in the pressure chamber.

Hereinafter, preferred specific examples of the flow rate regulating valve used in power steering according to the present invention will be described with reference to the drawings.

The figure shows a specific example 10 of the flow regulating valve used in the power steering of the present invention.

The flow rate regulating valve 10 used for the power steering may be provided independently in the hydraulic piping downstream of the oil pump (not shown), or may be integrated into the oil pump. , an inlet port 12 connected to the discharge side of the oil pump, and a reaction control port 12 of the power steering system (not shown).
A valve casing 11 with an outlet port 13 connected to the valve (not shown) side and a bypass port 14 connected to the suction side of its oil pump; Side port 13 and bypass port 1
4 and a valve chamber 15 formed in its valve casing 11 and its valve chamber 15.
an oil return control spool 17 that is reciprocally slidably disposed in the chamber 15 and adjusts communication between the inlet port 12 and the bypass port 14; and the valve chamber 15.
A vent turret 26 formed in the oil passage of the inlet side port 12 which is upstream of the vent turret 2
A metering orifice 28 formed in the throat portion 27 of 6 and its valve chamber 1
a metering bypass 32 connecting the metering orifice 28 to the oil passage of the outlet port 13 downstream of the valve chamber 15; A switching valve 29 is disposed at the connection point with the ring bypass 32 and switches and connects the upstream of the oil passage and the metering bypass 32 to the downstream of the oil passage, and cooperates with the oil return control spool 17. Been,
It includes a pilot communication passage 33 that supplies the metering bypass 32 side pressure oil to a back pressure chamber 34 formed in the valve chamber 15, and a return spring 35 disposed in the back pressure chamber. Manufactured.

Of course, the flow regulating valve 10 used in the power steering according to the present invention shown in the figure
is integrated into the oil pump at a suitable location, for example in the lower part.

That is, the valve casing 11 corresponds to the lower part of the casing of the oil pump, and is connected to the discharge side of the oil pump and has an inlet port 12 extending upward in a substantially vertical direction. and an outlet port 13 connected to the reaction control valve side of the power steering device and extending continuously downward from the inlet port 12 thereof, and connected to the suction side of the oil pump, A bypass port 14 is provided which extends upward in a substantially vertical direction in parallel with the inlet port 12.

Of course, the outlet port 13 is connected to the reaction control valve side of the power steering device via a hydraulic pipe (not shown).

A valve chamber 15 is laterally formed in the valve casing 11 to communicate the inlet port 12 with the bypass port 14 .

Of course, the valve chamber 15 connects its inlet port 12 to its bypass port at one end.
A hole is formed laterally from one side of the valve casing 11 so as to communicate with the port 14, and the open end side is closed with a plug (not shown).

Further, a ventilate 26 is formed in the valve casing 11 at a position below the inlet port 12.

A metering orifice 28 is formed in the throat portion 27 of the ventilate 26 thus formed.

Further, the valve casing 11 is formed with a metering bypass 32 that connects the metering orifice 28 to the outlet port 13 described above.

Further, in the valve casing 11, a pilot communication passage 33 is formed in the metering bypass 32, which connects the part near the metering orifice 28 and the above-mentioned part near the outside of the valve chamber 15. has been done.

Valve casing 11 so configured
An oil return control spool 17 for controlling communication between the inlet port 12 and the bypass port 14 is reciprocatably disposed in the valve chamber 15 of the valve chamber 15 .

The oil return control spool 17 has a relief valve chamber 1 inside.
9, the rear end is formed into a substantially cylindrical shape, and
A pressure oil inlet 20 and a pressure oil outlet 2 communicating with the relief valve chamber 19 on the upper outer circumferential surface.
1 is formed respectively, and a stopper 2 is provided at the tip.
5 is integrally formed with the spool body 18; a ball poppet 22 for opening and closing the pressure oil inlet 20 within the relief valve chamber 19;
It comprises a valve seat 23 and a return spring 24 disposed within the relief valve chamber 19 so as to press the ball poppet 22 against the pressure oil inlet 20.

If the oil return control spool 17 so configured is placed in the valve chamber 15 of the valve casing 11, it will cooperate with the oil return control spool 17 to control the valve.・Chayamba 1
A back pressure chamber 34 is formed in the outer portion of 5.

Of course, the back pressure chamber 34 is connected to the metering bypass 3 via the pilot communication passage 33 mentioned above.
2 has been contacted.

Further, a return spring 35 is arranged in the back pressure chamber 34 to press the oil return control spool 17 inward.

Therefore, the oil return control spool 17 is normally pressed inward by the return spring 35, and the stopper 25 at the tip of the spool body 18 is connected to the inner end surface of the valve chamber 15. placed.

Of course, in such a state, the inlet port 12
Communication with bypass port 14 has been severed.

Furthermore, in the valve casing 11 described above, the oil passage of the outlet port 13 downstream of the valve chamber 15 and its metering.
A switching valve 29 is disposed at a connection point with the bypass 32, a so-called connecting portion, and switches and connects the upstream of the oil passage and the metering bypass 32 to the downstream of the oil passage. That is, the switching valve 29 connects the upstream side and the downstream side of the oil passage, and the metering bypass 3.
2 and the downstream side of the oil passage.

The switching valve 29 is rotatably disposed in the valve casing 11 at a connecting portion between the outlet port 13 and the metering bypass 32, and has a substantially T-shaped communication hole; That is, in the outlet port 13, there is a communication hole 30 for communicating the upstream side and the downstream side of the switching valve 29;
The metering bypass 32 is provided with a communication hole 31 for communicating the metering bypass 32 with the downstream side of the switching valve 29.

Of course, the switching valve 29 selects communication between the upstream side and the downstream side of the switching valve 29 and the communication between the metering bypass 32 and the downstream side of the switching valve 29 at the outlet port 13. The shape can be arbitrary as long as it can be carried out in a practical manner, and for example, a spool type can also be applied.

Therefore, the internal combustion engine is operated with the switching valve 29 in the state shown in the figure, that is, with the upstream side and the downstream side of the switching valve 29 communicating with each other at the outlet port 13. , when the oil pump is driven, pressure oil corresponding to the rotation of the oil pump flows into the inlet port 1.
2 and passes through the bench turret 26.

Of course, since one end of the metering bypass 32 is closed by the above-mentioned switching valve 29, the pressure oil sent in this way does not reach the metering orifice 28 in the throat portion 27 of the ventilee 26. Almost without entering, the oil passes near the stopper 25 of the oil return control spool 17, passes through the outlet port 13 and the switching valve 29, is sent to the reaction control valve side of the power steering device, and is sent to the predetermined position. The steering wheel is placed in a state where it can be rotated with an operating force of .

Also, when the pressure of the pressure oil sent in this way is high, that is, when the internal combustion engine is operated at high speed, the pressure causes the oil return
As the control spool 17 is slid outward against the return spring 35, the inlet port 12 and the bypass port 14 are communicated, and a portion of the pressure oil is returned to the suction side of the oil pump. , the flow rate of the pressure oil sent from the outlet port 13 to the reaction control valve side of the power steering device is reduced.

Therefore, a state in which the steering wheel can be rotated with a larger operating force than the above-mentioned predetermined operating force, ie, a state in which the steering wheel is heavy, occurs.

Further, when the above-mentioned switching valve 29 is rotated approximately 90 degrees to the right, the metering bypass 32
and the downstream side of the switching valve 29 at the outlet port 13, and the outlet port 13 is connected to the downstream side of the switching valve 29.
3, the upstream portion of the switching valve 29 is shut off.

When the internal combustion engine is operated at high speed under such conditions and pressure oil supplied from the oil pump is sent to the inlet side port 12, the flow velocity near the metering orifice 28 in the throat portion 27 of the ventilee 26 increases. Static pressure decreases and oil
A pressure difference is created between the pressure oil delivered to the distal end of the return control spool 17 and the pressure oil passed through its metering orifice 28 and into the metering bypass 32.

Therefore, a portion of the pressure oil sent into the metering bypass 32 with a reduced flow rate and reduced static pressure is transferred via the pilot communication passage 33 to the back pressure of the valve chamber 15. Since a large pressure difference occurs between the pressure oil sent into the chamber 34 at the tip side of the oil return control spool 17 and the pressure oil in the back pressure chamber 34, the oil return control spool 17 The control spool 17 is slid outward against the return spring 35, and the inlet port 12 and the bypass
Port 14 is in communication with the oil return control spool 17 so that the pressurized oil at the tip side of the oil return control spool 17 is returned to the suction side of the oil pump through the bypass port 14.

In addition, the pressure oil whose flow rate is reduced in the metering bypass 32 is
It is sent to the reaction control valve side of the power steering device via the switching valve 29.

In other words, its reaction control
The pressure oil sent to the valve side is the oil return
Bypassing the tip side of the control spool 17,
Since the flow rate is significantly reduced by the metering orifice 28, even greater operating force is required to rotate the steering wheel, making the so-called steering operation even heavier.

As described above, by rotating the switching valve 29, it is possible to change the weight of the steering, that is, the feeling of operation.

Of course, if you want to change the steering weight according to the driver's preference, you can do so by operating inside the cab.
The switching valve 29 is configured to be rotatable, and for example, a servo motor (not shown) for rotating the switching valve 29 is installed, and a switching valve (not shown) connected to the servo motor is installed in the cab. (not shown).

The switching valve 29 can also be configured to rotate in response to movement of a change lever (not shown) of a transmission (not shown).

That is, in such a case, when using a low-speed gear in the transmission, the switching valve 29 is connected to the upstream and downstream sides of the switching valve 29 at the outlet port 13, as shown in the figure. and when using a high-speed gear, the switching valve 29 is configured to communicate between the metering bypass 32 and the downstream side of the switching valve 29 at the outlet port 13, For example, if the transmission control device has a change lever,
A switch is attached that is energized when selected and shifted to use a high gear, and is connected to a servo motor that rotates the switching valve 29.

Of course, the changeover valve 29 is always in its position when the switch is deenergized, i.e. when the change lever is selected and shifted to a lower gear, or when it is in the neutral position. It is desirable to provide a return spring (not shown) for rotating the switching valve 29 so as to communicate the upstream side and the downstream side of the switching valve 29 at the outlet port 13.

With such a configuration, in the case of normal high-speed driving, the switching valve 29 is rotated to connect the metering bypass 32 and the downstream side of the switching valve 29 at the outlet side port 13, and the power steering device Since the flow rate of pressure oil sent to the reaction control valve side of the engine is drastically reduced, steering operations become heavier.

In addition, in the case of low-speed driving, the switching valve 29 is returned to the state shown in the figure, and the upstream and downstream sides of the switching valve 29 at the outlet port 13 are connected, and the reaction of the power steering device is controlled.・The flow rate of pressure oil sent to the control valve side is not drastically reduced, and steering operation becomes lighter as usual.

Therefore, when a car is traveling downhill while using the engine and brake, or when traveling uphill in a low gear while the engine is running, even if the internal combustion engine is rotating at high speed, the steering operation becomes lighter, especially when driving around curves. In the case of a slope with many slopes, the steering operation becomes easier.

According to this invention having the above structure, the weight of the steering wheel can be adjusted depending on the driving condition of the vehicle and the road surface on which the vehicle is traveling, and is used in power steering to reduce driver's fatigue due to steering operation. A flow rate regulating valve is obtained.

[Brief explanation of drawings]

The figure is a longitudinal sectional view showing a specific example of a flow rate regulating valve used in power steering according to the present invention. 10...Flow control valve used in power steering, 11...Valve casing, 12...
Inlet side port, 13... Outlet side port, 14...
Bypass port, 15...valve chamber,
17...Oil return control spool, 26...Ventilary, 27...Throat part, 28...Metering orifice, 29
...Switching valve, 32...Metering bypass, 33...Pilot communication passage, 34...Back pressure chamber, 35...Return spring.

Claims (1)

[Claims] 1. An inlet side port connected to the discharge side of the oil pump, an outlet side port connected to the reaction control valve side of the power steering device, and an outlet side port connected to the suction side of the oil pump. a valve chamber formed in the valve casing by connecting the inlet port to the outlet port and the bypass port; an oil return control spool operable to adjust communication between the inlet port and the bypass port; and a ventilate formed in the inlet port oil passage upstream of the valve chamber. , a metering orifice formed in the throat of the ventilate, a metering bypass connecting the metering orifice to the oil passage of the outlet port downstream of the valve chamber, and a le spool. , is placed at the connection point between the oil passage of the outlet side port downstream of the valve chamber and its metering bypass, and switches and connects the upstream of the oil passage and the metering bypass to the downstream of the oil passage. A switching valve, a pilot communication passage that cooperates with the oil return control spool and supplies the metering bypass side pressure oil to a back pressure chamber formed in the valve chamber, and the back pressure chamber. A flow regulating valve used in power steering, including a return spring located in the