JPH0147345B2 - - 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, making the steering operation difficult. It was difficult to perform a satisfactory steering operation on a slope with many curves that required maneuvering.

The purpose of this invention is to make the steering operation light during normal driving, and to make the steering operation easier when driving at high speed.
Slightly increase the weight of the steering to stabilize the steering, and when driving downhill while using the engine brake, or when driving uphill using a low gear with the engine running. To provide a flow rate regulating valve used in power steering, which reduces the weight of the steering wheel, improves the operability of the steering wheel, and enables safe driving.

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 the oil pump, and the inlet port connected to the bypass port. control the communication between the valve chamber formed in the valve casing, the restriction formed between the outlet port and the valve chamber, and the inlet port and the bypass port so as to an oil return control reciprocatingly slidably disposed in the valve chamber so as to form a back pressure chamber on the opposite side of the upstream side of the restriction and toward the outside of the valve chamber; A spool, a pilot communication passage formed in the valve casing that connects the downstream side of the throttle to the back pressure chamber, and a pilot communication passage formed in the valve casing that connects the upstream side of the throttle to the pilot communication passage. built into the casing,
and a short circuit valve that connects the upstream side of the throttle to the back pressure chamber via the pilot communication passage when the oil pressure on the upstream side of the throttle exceeds a predetermined pressure. be.

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 schematically 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 with an outlet port 13 connected to the valve (not shown) side and a bypass port 14 connected to the suction side of the oil pump.
between a casing 11, a valve chamber 15 formed in the valve casing 11 so as to communicate the inlet port 12 with the bypass port 14, and the outlet port 13 and the valve chamber 15; An orifice 16 as a restriction formed in the valve chamber 15 is arranged to be reciprocally slidable in the valve chamber 15 so as to control communication between the inlet side port 12 and the bypass port 14. A back pressure chamber 26 is formed on the opposite side of the valve chamber 15 toward the outside of the valve chamber 15, and the orifice 1
an oil return control spool 17 with a throttle rod 24 that changes the opening area of the valve casing 1;
The pilot communication passage 27 formed in 1 and the upstream side of the orifice 16 are connected to the pilot communication passage 27 formed in
7 is built into the valve casing 11, and when the oil pressure upstream of the orifice 16 exceeds a predetermined pressure, the oil is connected to the upstream side of the orifice 16 via the pilot communication passage 27. and a short circuit valve 31 communicating with the back pressure chamber 26.

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 which is connected to the reaction control valve side of the power steering device and extends continuously from the inlet port 12 in the lateral direction, and is connected to the suction side of the oil pump. , and a bypass port 14 that extends upward in a substantially vertical direction alongside 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).

Moreover, in the valve casing 11,
Its outlet port 13 and its valve chamber 1
5, an orifice 16 is formed therebetween.

Furthermore, a pilot communication passage 27 is formed in the valve casing 11, which communicates the downstream side of the orifice 16 near the outlet port 13 with the outer portion of the valve chamber 15.

Valve casing 11 so configured
The valve chamber 15 is configured to control communication between the inlet port 12 and the bypass port 14 and to regulate the amount of oil supplied from the inlet port 12 to the outlet port 13. , an oil return control spool 17 that changes the opening area of the orifice 16 is arranged so as to be able to slide back and forth.

That is, the oil return control spool 17 is formed into a substantially cylindrical shape with a relief valve chamber 19 inside, and has a rear end,
and its relief valve on the upper periphery.
A spool body 1 in which a pressure oil inlet 20 and a pressure oil outlet 21 are respectively formed and communicated with a chamber 19.
8, and a throttle which is attached to the tip of the spool body 18 and is passed through the orifice 16 to change the opening area of the orifice 16.
A rod 24 and a ball in its relief valve chamber 19 that opens and closes its pressure oil inlet 20.
It consists of a poppet 22 and a return spring 23 disposed within the relief valve chamber 19 to urge 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 26 is formed in a portion closer to the outside of 5.

Of course, the back pressure chamber 26 is connected to the outlet port 13 on the downstream side of the orifice 16 via the pilot communication passage 27 mentioned above.

Further, a return spring 25 is arranged in the back pressure chamber 26 to press the oil return control spool 17 inward.

Therefore, the oil return control spool 17 is normally pressed inward by the return spring 25, and communication between the inlet port 12 and the bypass port 14 is cut off. Of course, in such a state, the tip of the throttle rod 24 in the oil return control spool 17 is located away from the orifice 16 and closer to the outlet side port 13, so the opening area of the orifice 16 has been made to the max.

Furthermore, within the valve casing 11, on the upstream side of the orifice 16, and
Near the inside position of the valve chamber 15, when the pressure of the oil upstream of the orifice 16, that is, the pressure of the oil supplied from the oil pump, exceeds a predetermined pressure, the orifice 16 A short circuit valve 31 is provided that communicates the upstream side and the downstream side via the pilot communication passage 27.

That is, in the valve casing 11, a short circuit valve chamber 28 is formed at a position closer to the inside of the valve chamber 15, and extends downward and is perpendicular to the pilot communication passage 27. A short circuit valve 31 is disposed within the valve chamber 28 for reciprocating movement.

The short circuit valve 31 includes a cylindrical valve body 32, a ring groove 33 formed around the upper side surface of the valve body 32, and a ring groove 33 and an upper end of the valve body 32. and within the short circuit valve chamber 28,
It is comprised of a return spring 35 for pushing the valve body 32 upward.

Accordingly, the valve body 32 is reciprocally slidably disposed within the short circuit valve chamber 28 and further
The return spring 35 is arranged below the short circuit valve chamber 28, and in this state a plug 36 is fitted below the short circuit valve chamber 28.

Of course, the valve body 32 is normally
Since it is pushed upward by the return spring 35, the valve body 32
Although the communication between the ring groove 33 and the pilot communication passage 27 is cut off, in such a state, in order to connect the pilot communication passages 27 on both sides around the shot circuit valve 31, The short circuit valve
At approximately the center of the inner circumference of the chamber 28, there is a ring groove 2 that connects the pilot communication passages 27 on both sides.
9 is formed.

In other words, even when the valve body 32 is pushed upward by the return spring 35, the above-mentioned orifice 16
The outlet port 13 on the downstream side of the oil return control spool 17 and the back pressure chamber 26 on the rear end side of the oil return control spool 17 are
7 and a ring groove 29.

Of course, the short circuit valve 31
When the pressure of oil supplied from the oil pump to the inlet port 12 exceeds a predetermined pressure, the ring groove 33 and its pilot are pushed downward against the return spring 35. The communication passage 27, in other words, the upstream side and the downstream side of the orifice 16 are configured to communicate with each other, and the above-mentioned predetermined pressure is determined by the spring constant of the return spring 35. Ru.

Therefore, the spring constant of the return spring 35 is determined depending on the engine speed, such as when the vehicle is traveling downhill while using engine braking or when the vehicle is traveling uphill using a low gear with the engine running. When the pressure of the oil supplied from the oil pump to the inlet port 12 is extremely high, the short circuit valve 31 is forced downward and the orifice 1
The spring constant is set to a predetermined value so that the upstream side and the downstream side of the spring 6 can be communicated with each other.

Of course, in the case of normal high-speed driving, a high gear is used, so the engine speed in that case is lower than the engine speed in the above case.
Therefore, the short circuit valve 31
is maintained in an upwardly pushed state by its return spring 35.

Next, the operation of the flow rate regulating valve 10 used in the power steering according to the present invention will be explained.

First, when the internal combustion engine is operated and the oil pump is driven, oil corresponding to the rotation of the oil pump is sent to the inlet port 12, but if the engine is being operated at low speed, the oil pump is sent to the inlet port 12. 12
The oil return control spool 17 is located on the orifice 16 side (left side in the figure) because the amount of oil sent to the orifice 16 is relatively small and the pressure drop at the orifice 16 is small. 12 and the bypass port 14, the oil passes through the orifice 16 and exits from the outlet port 13.
Sent to the reaction control valve side of the power steering device.

Therefore, the oil supplied from the oil pump is not returned to the suction side of the oil pump via the bypass port 14.
The signal is sent to the reaction control valve side, and the steering wheel is placed in a state where it can be rotated with a predetermined operating force, that is, a light operating force.

In addition, during high-speed operation, the amount of oil sent to the inlet port is large, and the pressure drop at the orifice 16 is large, so the oil return control spool 17 is pushed outward against the return spring 25 (Fig. right side), and its inlet side port 12 and bypass port 1
4 is connected, and some of the oil is
The oil return control spool 17 is returned to the suction side of the pump and
As the oil return control spool 17 slides further to the right, the orifice 16 is throttled by the throttle rod 24, which further increases the pressure drop. This increases the amount of oil returned to the suction side of the oil pump, and reduces the amount of oil sent from the outlet port 13 to the reaction control valve side of the power steering device.

Therefore, a state in which the steering wheel can be rotated with a larger operating force than the above-mentioned predetermined operating force,
The so-called steering is heavy and placed in a stable state.

Furthermore, when driving downhill while using the engine and brake, or when driving uphill using a low gear while the engine is running, the engine speed is high as in the case of high-speed operation, so the exit side The amount of oil sent from port 13 to the reaction control valve side of the power steering device decreases, but when turning the wheel significantly in a curve, the oil pressure increases, so the above-mentioned short circuit valve 31 is pushed downward against the return spring 35, and the ring groove 33 of the valve body 32 and the ring groove 29 of the short circuit valve chamber 28 are aligned, and the upstream and downstream sides of the orifice 16 are aligned. , are connected via the pilot communication path 27.

Therefore, the pressure difference between the upstream side and the downstream side of the orifice 16 decreases, so the oil return control valve returns to the left side and bypasses the bypass port 1.
4 is closed, the amount of oil sent to the reaction control valve side of the power steering device increases, so even if the oil pump is rotating at high speed as described above,
The flow of oil sent to the reaction control valve side is large, and the steering is placed in a state where it can be rotated with a light operating force.

According to the above invention, the pilot communication passage communicates the downstream side of the throttle with the back pressure chamber to connect the valve.
A short circuit valve is formed in the casing and is incorporated within the valve casing at a point where the short circuit valve communicates the upstream side of the restriction with the pilot communication passage, and the short circuit valve is incorporated within the valve casing at a point where the short circuit valve communicates the upstream side of the restriction with the pilot communication passage. When the pressure of
When driving at high speeds, the steering operation becomes important, and the steering operation is stable, and it is necessary to use the engine brake when going downhill with a curve, or in a low gear while using the engine when going uphill with a curve. When driving using a steering wheel, the steering operation becomes lighter, improving maneuverability and enabling safe driving.

[Brief explanation of drawings]

The figure is a schematic diagram showing a specific example of a flow rate regulating valve used in power steering according to the present invention. 10...Flow control valve used for power steering, 11...Valve casing, 12...
...Inlet side port, 13...Outlet side port, 14...
...Bypass port, 15... Valve chamber, 16... Orifice, 17... Oil return control spool, 24... Throttle rod, 27... Pilot communication passage, 31
...Short circuit valve.

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 to communicate the inlet port with the bypass port; a valve chamber formed in the valve casing with the outlet port communicating with the bypass port; a constriction formed between the valve chamber and the upstream opposite side of the constriction; an oil return control spool forming a back pressure chamber on the outside of the valve chamber; and a pilot formed in the valve casing with the downstream side of the restriction communicating with the back pressure chamber. It is built into the valve casing at the point where the communication passage and the upstream side of the throttle communicate with the pilot communication passage, and when the oil pressure on the upstream side of the throttle exceeds a predetermined pressure, the pilot communication passage is connected. A flow control valve used in power steering including a short circuit valve communicating the upstream side of the restriction to the back pressure chamber via a passage.