JPH0669063U - Flow control valve device - Google Patents

Abstract

(57) [Summary] [Purpose] A flow control valve device having flow control characteristics including non-return drooping characteristics is simply configured with a small number of parts and the axial length is shortened. A connector 5 having a pressure fluid supply passage hole 5a is provided at the opening end of the valve housing hole 2 of the flow control spool valve 3. The restriction spool 6 slidably disposed in the large diameter hole 5b formed on the inner end side of the connector is provided with the small diameter cylindrical portion 6a facing the valve accommodation hole. A restriction passage 10 is formed between the small-diameter cylindrical portion and the large-diameter hole to restrictively connect the pressure fluid supply passage that opens from the connector outer peripheral portion into the large-diameter hole. An orifice 20 for actuating the flow control spool valve is provided in the middle of the pressure fluid supply passage hole in the restriction spool.
The fixed orifice portion 21 constituting the above is provided. Further, a variable orifice portion 22 constituting an orifice is provided on the outer end side of the large diameter hole of the connector so that opening / closing can be controlled by the movement of the limiting spool.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention is configured so that pressure oil from a rotation speed sensitive hydraulic pump driven by an engine can be controlled with a required flow rate characteristic in a hydraulic power steering device as a fluid device. The flow control valve device has a drooping characteristic (flow rate drooping) that decreases the supply flow rate to the fluid equipment in response to an increase in the pump discharge flow rate with an increase in the pump rotation speed. The present invention relates to a flow control valve device having a so-called non-returning drooping characteristic, in which there is no possibility that the fluid will return due to the influence of a pressure increase on the fluid equipment side.

[0002]

[Prior art]

 For example, in a power steering apparatus mounted on an automobile to reduce the steering operation force of a driver, a pump which is a hydraulic pressure generation source thereof is usually rotationally driven by an engine of the automobile. The amount of hydraulic oil discharged from this pump increases or decreases in proportion to the change in the engine speed.

Therefore, such a rotation speed-sensitive pump can supply a sufficient amount of fluid to a fluid device such as the power steering device even in the low engine speed region, that is, when the pump discharge amount is small. It is required to have a capacity. However, simply setting the pump capacity in this way would cause an unnecessarily large flow rate to be supplied to the power steering device in the high engine speed range, so that the excess flow rate could be returned to the tank side. It will be necessary.

Therefore, conventionally, an orifice is provided in the middle of the hydraulic pressure supply passage from the pump to the power steering device, and the spool valve serving as the flow control valve is opened by the differential pressure across the orifice to open the power steering device. A part of the pressure oil (excess flow rate) not required for operation in the engine can be smoothly returned to the tank side without generating flow path resistance, so that the flow rate supplied to the power steering device can be maintained below a certain amount. The configuration is generally performed.

By the way, in the pressure oil supply system for the power steering apparatus described above, the pressure oil supply amount in a high rotation range of the engine of the vehicle becomes a problem in terms of running stability of the vehicle. In other words, when the car is running at high speed, if the steering wheel is too light, it is easy for the driver to feel uneasy, and in order to eliminate this, the pressure oil supply is increased to increase the rotation speed. Along with this, providing a so-called drooping characteristic that reduces the value to some extent helps to stabilize the vehicle at high speeds, give a proper steering feel, and save energy.

Therefore, the above-mentioned orifice for flow rate control is constructed as a variable throttle structure so as to function as a constant throttle when the vehicle is stopped, running at low or medium speeds, and is narrowed down at high speeds. It is known that the resulting pressure difference increases the return flow rate to the tank and reduces the amount of pressure oil supplied to the power steering device side.

However, if flow control including such drooping characteristics is attempted by simple variable control of the orifice, drooping will be performed when the power steering system is not operating (no load). Even if the prescribed flow rate control can be performed initially, when the power steering device is operated for steering, a pressure rise occurs in the pressure oil supply system, which changes the differential pressure across the orifice in the supply passage. Depending on the pressure difference, the spool valve acts to limit the recirculation of the excess flow rate, which increases the supply flow rate, which has been decreased according to the degree of pressure increase, and returns to the original state. An unfavorable phenomenon is occurring.

Therefore, in the above-mentioned flow control valve device, a restriction passage is provided in a part of the supply passage, and a control spool or a control sleeve for restricting the flow that responds to the pressure difference before and after the restriction passage is provided. There have been various proposals for reducing the amount of restriction of the orifice, including, for example, JP-A-57-4469 and JP-A-61-77567. That is, the orifice can be variably controlled based on the increase in the pump discharge amount due to the increase in the pump rotation speed, regardless of the displacement of the spool valve. It is designed to prevent the flow rate from returning to the original flow rate.

With this configuration, the problem that occurs in the above-described flow rate control by the simple variable control of the orifice is caused by the control spool that variably controls the orifice according to the pressure difference between the restriction passage and the pressure before and after the restriction passage. It can be solved with, and its usefulness is great.

[0010]

[Problems to be solved by the device]

 However, in the flow control valve device for obtaining the non-reset type drooping characteristics by the above-mentioned conventional structure, the former one has a large number of constituent parts, and the structure is complicated, and each part is required to have a machining accuracy. However, there was a problem that the flow control characteristics could not be controlled.

On the other hand, according to the latter conventional device, an orifice is formed in the outer peripheral portion of the union having the pressure fluid supply passage, and a control sleeve having a flange is slidably provided in the outer peripheral portion of the union. Normally, the orifice is urged in the opening direction, and as the flow rate increases, it is operated by the fluid pressure difference before and after the restriction passage between the outer peripheral portion of the flange and the valve hole, and the orifice is reduced to supply. Since the flow rate is reduced, it has advantages such as a simpler structure than the former conventional example.

However, even in the latter conventional device as described above, the number of constituent parts is large, the processing of each part is complicated, the cost is apt to increase, and the assemblability is also a problem. The overall length of the device itself became particularly long in the axial direction, and it was unavoidable to make it larger. Since such a flow rate control valve device requires a space to be incorporated, there is a problem that the entire pump to which this type of flow rate control valve is attached becomes large.

The present invention has been made in view of the above circumstances, and has an extremely simple structure with a minimum necessary number of constituent components and a flow control characteristic including non-return drooping characteristics. The objective is to obtain a flow control valve device that is smaller in size, especially in the axial direction, and that is easy to assemble and cost.

[0014]

[Means for Solving the Problems]

 In order to meet such a demand, the flow control valve device according to the present invention is provided at the opening end of the valve accommodating hole of the spool valve for flow control for recirculating a part of the pressure fluid from the pump, and the fluid control valve device at the outer end side. A connector having a pressure fluid supply passage hole for equipment and a small-diameter cylindrical portion on the inner end side of which is slidably arranged in a large-diameter hole formed on the inner end side of the connector is the valve. A restriction spool that faces the inside of the accommodation hole to form a restriction passage between the small-diameter cylindrical portion and the large-diameter hole for restrictively communicating the pressure fluid supply passage that opens from the outer peripheral portion of the connector into the large-diameter hole. And a fixed orifice portion that constitutes an orifice for operating the flow control spool valve is provided in the middle of the pressure fluid supply passage hole formed from the inner end to the outer end of the restriction spool. Fixed Orifice A variable orifice portion constituting the orifice with parts, the large-diameter hole outer end side of the connector, even for a is provided so as to be opened and closed controlled by the movement restriction spool.

[0015]

[Action]

 According to the present invention, the flow control spool valve is operated in a required state by the differential pressure across the orifice that occurs in accordance with the increase in pump discharge flow rate as the pump speed increases, and the excess flow rate is transferred to the tank side. Recirculate and control the supply flow rate to the fluid equipment properly. In addition, the rotational speed of the pump is increased by operating the limiting spool with the differential pressure before and after the limiting passage formed by the small-diameter tubular portion of the limiting spool that is slidable in the large-diameter hole at the inner end of the connector. When the pressure rises and the flow rate from the supply side passage increases, the differential pressure before and after the restriction passage is suppressed from rising more than necessary, and the variable orifice portion that constitutes the orifice is closed. It is possible to obtain the desired drooping characteristics, and as a result, it is possible to perform flow control with a non-returning drooping characteristic in the required state.

[0016]

【Example】

 FIG. 1 shows an embodiment of a flow control valve device according to the present invention. In this figure, in the present embodiment, the device of the present invention is used in a pressure oil supply system for a hydraulic power steering device. Explain the situation.

First, the overall schematic configuration will be briefly described. Reference numeral 1 is a housing for a hydraulic pump or the like, and 2 is a valve accommodating hole formed in the housing 1 with a large diameter on the opening side. A spool valve 3 with a relief valve is slidably housed and held in a small diameter portion 2a of the second portion 2, and the large diameter portion 2b is connected to a power steering device (the flow path switching valve side) PS (not shown). A connector 5 having a pressure oil outlet 4 and a pressure oil passage hole 5a continuous with the pressure oil outlet 4 is closed by being screwed and fixed to the housing 1, and the inner end 5c of the connector 5 has a large diameter. It faces the inside of the portion 2b in a press-fitted state.

Reference numeral 6 is slidable in a large-diameter hole 5 b formed on the inner end side of the connector 5, and a small-diameter cylindrical portion 6 a on the inner end side thereof is exposed in the valve housing hole 2. A restriction spool for controlling the flow rate, which is arranged in a closed state, has a pressure fluid supply passage that opens from the outer peripheral portion of the connector 5 into the large diameter hole 5b between the small diameter cylindrical portion 6a and the large diameter hole 5b. A limiting passage 10 that limits the flow rate of the pressure oil supplied from the pump P by forming a limited communication is formed.

Reference numeral 7 in the drawing denotes a ring-shaped member that is locked to the open end portion of the large-diameter hole 5b of the connector 5 by a set ring 7a. The inner diameter portion 7b of the ring-shaped member 7 and the limiting spool 6 are The restriction passage 10 is formed between the small diameter tubular portion 6a and the outer peripheral portion. The ring-shaped member 7 regulates the range of movement of the limiting spool 6 to the inner end side, which is biased by the spring 8 arranged on the outer end side in the large diameter hole 5b. Doubles as

Further, in the valve housing hole 2, a supply side passage 11 is opened in the large diameter portion 2b, an oil pump P is connected, and a return side passage 12 is opened in the small diameter portion 2a, and the tank T is connected to the tank T. It is connected. The spool valve 3 in the small-diameter portion 2a is biased toward the large-diameter portion 2b by the spring 9. When the valve is not operated, the tip land portion 3a extends from the inner end of the connector 5 or the like. The landing portion 3a of the spool valve 3 blocks the supply-side passage 11 and the return-side passage 12 in this state.

Reference numeral 3b in the drawing denotes the tip of the spool valve 3 with which the small-diameter cylindrical portion 6a of the limiting spool 6 is in contact when not in operation. The tip 3b has an opening in the small-diameter cylindrical portion 6a. A slit 3c is formed so as not to close the pressure oil supply passage hole 6b in the spool 6. It goes without saying that a passage hole or a slit may be formed in the radial direction at the tip end side of the small-diameter cylindrical portion 6a instead of the slit 3c.

The pressure oil flowing from the pump P into the large-diameter portion 2b via the supply-side passage 11 flows from the annular space in the annular groove 14 formed in the outer peripheral portion of the connector 5 to the connector. A plurality of holes 15 formed in the radial direction so as to open in the large diameter hole 5b, an annular groove 16 in the outer peripheral portion of the restriction spool 6, and an inner end side flange 6c of the restriction spool 6 are formed. The space between the spool valve 3 and the pressure oil supply passage 6b in the limiting spool 6 and the outer end side space of the large diameter hole 5b of the connector 5 from the space between the spool valve 3 and the space. The oil is delivered from the pressure oil outlet 4 through the pressure oil passage hole 5a to the power steering device PS side as a fluid device.

Reference numeral 20 is an orifice for operating the flow rate control spool valve 3, and this orifice 20 is provided in the middle of a pressure oil supply passage hole 6 b formed from the inner end to the outer end of the restriction spool 6. And a variable orifice portion 22 which is provided on the outer end side of the connector large diameter hole 5b and whose opening and closing can be controlled by the movement of the limiting spool 6.

Here, in the present embodiment, the variable orifice portion 22 described above is provided with a hole portion 22a which is formed by opening the variable orifice portion 22 at the annular groove 14 portion of the connector 5 toward the outer end side of the large diameter hole 5b. Shows a case where it is constituted by the land portion 22b on the outer end side of the limiting spool 6 that moves so as to open and close. In particular, the variable orifice portion 22 is provided when the limiting spool 6 moves when the pressure oil from the pump P becomes a predetermined amount or more and the accompanying pressure difference across the limiting passage 10 becomes a predetermined amount or more. It is designed to be closed.

According to such a flow rate control valve device, the pressure oil flowing from the pump P into the large diameter portion 2b through the supply passage 11 enters the pressure oil supply chamber by the annular groove 14, As described above, the fluid pressure is applied to the tip portion 3b of the spool valve 3 through the restriction passage 10 in the small-diameter tubular portion 6a of the restriction spool 6, and the pressure oil is fed from the pump P. When it is held, it passes through the passage hole 6b in the restriction spool 6 through a gap passage such as the slit 3c at the valve spool tip portion 3b which is slightly leftward in the figure against the biasing force due to the fluid pressure, It is supplied to the PS side from the large diameter hole 5b of the connector 5, the pressure oil passage hole 5a, and the outlet 4.

Further, the flow from the above-mentioned pump P through the supply-side passage 11 to the return-side passage 12 in the small diameter portion 2a and the passage hole 6b in the limiting spool 6 as the pressure oil supply passage will be described. . That is, as described above, the pressure oil that reaches the front end side chamber 30 of the spool valve 3 from the pump P through the restriction passage 10 always causes the fluid pressure thereof to act on the spool valve front end portion 3b, and at the same time, the spool valve front end portion 3b. 3b is in contact with the small-diameter cylindrical portion 6a of the limiting spool 6 and flows into the pressure oil supply passage hole 6b from the opening, and the large-diameter hole 5b is passed through the fixed orifice portion 21. Is led to the outer side chamber. At this time, the outer end side chamber is also guided from the annular groove 14 portion of the connector 5 through a hole portion 22a forming a variable orifice portion 22.

In this state, when the flow rate that flows through each of the above-described paths increases, the spool valve 3 moves to the position shown in FIG. 2 due to the pressure difference before and after the orifice 20 between the fixed orifice portion 21 and the variable orifice portion 22. As shown in the drawing, the land portion 3a moves to the left in the drawing, and the land side passage 12 gradually opens. Due to the movement of the spool valve 3, a part of the pressure oil from the pump P flows to the PS side through the pressure oil supply passage hole 6b and the hole 22a of the variable orifice portion 22, and the rest flows to the return side. It will flow to passage 12.

Further, the limiting spool 6 is normally urged by the spring 8 toward the spool valve 3 side, but the flow rate flowing through the limiting passage 10 portion increases, and the pressure difference before and after that is greater than or equal to a predetermined value. Then, as shown in FIG. 3, it moves to the right side in the large-diameter hole 5b of the connector 5, and when the amount of movement exceeds a predetermined value, the hole 22a is moved to the land portion of the restriction spool 6. It is closed by 22b, and the variable orifice portion 22 is closed. Then, in this state, the throttle amount at the orifice 20 (21, 22) that is operated according to the pressure difference before and after the restriction passage 10 and operates the spool valve 3 for flow control is variably controlled to a required state. However, it is possible to obtain drooping characteristics as the supply flow rate.

Further, when the pressure difference before and after the restricting passage 10 becomes further larger and the restricting spool 6 becomes in the state shown in FIG. 4, from the inner diameter portion of the ring-shaped member 7 forming the restricting passage 10. Although the small-diameter cylindrical portion 6a of the restriction spool 6 comes out, the pressure difference before and after the restriction passage 10 becomes small. At this time, the restriction spool 6 is caused by the pressure difference before and after the fixed orifice portion 21 in the passage hole 6b. It is possible to obtain a flow rate control valve device that is maintained in the state shown in (1) and operates a stable flow rate limiting function, which has a non-returning drooping characteristic as a pressure oil supply characteristic.

In the flow rate control valve device having the above-described configuration, the pressure oil in the pressure oil supply side passage upstream of the fixed orifice portion 21 from the limit spool 6 portion through the limit passage 10 becomes the spool valve 3 The pressure is exerted on the tip portion 3b of the nozzle, and the pressure oil on the downstream side of the orifice 20 by the fixed orifice portion 21 and the variable orifice portion 22 passes through the damper orifice 31a and the passage hole 31b in the housing 1 and is discharged from the spool. It is connected to a spring chamber 9a which is the other chamber of the valve 3 so that the spool valve 3 is operated.

According to the flow rate control valve device configured as described above, in the low speed rotation range (low flow rate range) of the pump P driven by the engine of the automobile, as shown in FIG. Is held at a predetermined position by approaching the limiting spool 6 side by the urging force of the spring 9, and disconnects the pressure oil supply side passage 11 and the return side passage 12 from each other. It is urged by the urging force and maintained in the initial position. Then, in this state, the entire amount of the pressure oil discharged from the pump P is supplied to the power steering apparatus PS side. (This corresponds to the portion indicated by A in FIG. 5.)

Next, as the pump speed gradually increases, the discharge flow rate increases, and the differential pressure before and after the orifice 20 due to the fixed orifice portion 21 and the variable orifice portion 22 acts on the spool valve 3 for flow rate control. When the spool valve 3 starts to move to the left side in the figure and the tip side chamber 30 on the supply side and the pressure oil supply side passages 11 and 6b are communicated with the reflux side passage 12, as shown in FIG. The flow rate that is recirculated and supplied to the power steering apparatus PS is gradually reduced and supplied from the maximum supply flow rate indicated by Q1 in FIG. (This corresponds to the portion indicated by B in FIG. 5.)

Further, when the pump speed increases and the pump discharge flow rate further increases, the pressure difference before and after the restriction passage 10 increases, and as shown in FIG. Defeat the biasing force of 8 and move it to the right side in the figure. As a result, the restricted spool 6 gradually starts to squeeze the variable orifice portion 22 and finally closes the variable orifice portion 22 so that only the fixed orifice portion 21 functions as the orifice 20. At this time, the differential pressure before and after the fixed orifice portion 21 becomes maximum, the spool valve 3 is moved to the right, and the recirculation amount increases. (See Figure 3).

Therefore, due to the movement of the spool valve 3 as described above, the supply flow rate to the power steering apparatus PS is reduced as indicated by C in FIG. 5, and further, as shown in FIG. Is closed and the passage area in the restricted passage 10 is increased, it is maintained at a constant amount (Q2) as indicated by D in FIG.

As a result, the flow rate supplied to the power steering apparatus PS is reduced, so-called drooping characteristics are obtained, the steering feeling is optimized, and the stability when the vehicle is traveling at high speed is enhanced. It is possible to reduce the horsepower consumption during high-speed traveling.

Further, in the above-described configuration, when the flow rate exceeds a certain level, the restriction passage 10 is opened, and the restriction spool 6 is maintained at a predetermined position, so that the pressure difference before and after the restriction passage 10 is changed. The flow control function having a non-returning drooping characteristic can be exhibited by obtaining an appropriate movement of the limiting spool 6.

It is needless to say that the present invention is not limited to the structure of the embodiment described above, and the shape, structure, etc. of each part of the flow control valve device can be appropriately modified or changed. For example, the variable orifice portion 22 whose opening / closing is controlled according to the movement of the limiting spool 6 is not limited to the structure of the above-described embodiment, and as shown in FIG. An annular groove 40 is formed in the annular groove 40, and the upstream side of the fixed orifice portion 21 is connected to the annular groove 40 by a passage hole 41, whereby the variable orifice portion 22 can be closed by a land portion 22b at the tip of the spool 6. You may comprise.

Further, as shown in FIG. 7, a small diameter portion 42 is provided on the outer end side of the limiting spool 6, and the variable orifice portion 22 is formed by gradually inserting the small diameter portion 42 into the passage hole 5a. The variable orifice portion 22 may be configured to be able to be closed by the step portion 43 on the base end side of the small diameter portion 42.

[0039]

As described above, according to the flow control valve device of the present invention, the flow control spool valve for recirculating a part of the pressure fluid is provided at the opening end of the valve storage hole and is provided at the outer end side. The connector having a pressure fluid supply passage hole to the fluid equipment and the small-diameter cylindrical portion slidably arranged in the large-diameter hole formed on the inner end side of the connector and on the inner end side are described above. A restriction spool that faces the valve housing hole to form a restriction passage between the small-diameter cylindrical portion and the large-diameter hole for restrictively communicating the pressure fluid supply passage that opens from the outer peripheral portion of the connector into the large-diameter hole. And a fixed orifice portion that constitutes an orifice for operating the flow control spool valve is provided in the middle of the pressure fluid supply passage hole formed from the inner end to the outer end of the restriction spool. Fixed orifice The variable orifice part that constitutes the above-mentioned orifice together with the control part is provided on the outer end side of the large-diameter hole of the connector so that opening and closing can be controlled by the movement of the limiting spool. Flow control characteristics including looping characteristics can be achieved with a very simple structure with the minimum required number of components, and the overall size can be reduced, especially the axial length can be shortened. It has various excellent effects such as being excellent.

In particular, according to the present invention, the restriction passage for obtaining the non-return drooping characteristic and the restriction spool operated by the pressure difference before and after the restriction passage are incorporated in the large diameter hole in the connector, Compared with the conventional device, the axial length can be greatly shortened, the structure can be simplified, and the assembling property can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part showing an embodiment of a flow control valve device according to the present invention.

FIG. 2 is a cross-sectional view of essential parts for explaining an operating state of the flow control valve device shown in FIG.

FIG. 3 is a cross-sectional view of an essential part for explaining an operating state of the flow control valve device shown in FIG.

FIG. 4 is a cross-sectional view of an essential part for explaining an operating state of the flow control valve device shown in FIG.

FIG. 5 is a characteristic diagram for explaining a flow rate control characteristic of the device of the present invention.

FIG. 6 is a schematic sectional view showing another embodiment of the flow control valve device according to the present invention.

FIG. 7 is a schematic sectional view showing another embodiment of the flow control valve device according to the present invention.

[Explanation of symbols]

 1 Pump Housing 2 Valve Storage Hole 2a Small Diameter Section 2b Large Diameter Section 3 Flow Control Spool Valve 4 Pressure Oil Outlet (Pressure Fluid Outlet) 5 Connector 5a Pressure Oil Supply Side Passage Hole 5b Large Diameter Hole 6 Restriction Spool 6a Small Diameter Tube Shaped portion 6b Supply passage hole 7 Ring-shaped member 7b Inner diameter portion 8 Spring 9 Spring 10 Restricted passage 11 Supply side passage 12 Reflux side passage 13 Locking pin 14 Annular groove 15 Opening 16 Annular groove 17 Passage hole 20 Orifice 21 Fixed orifice portion 22 Variable orifice part 22a Hole part 22b Land part 30 Tip side chamber P pump T tank PS Power steering device (fluid device)

Claims (1)

[Scope of utility model registration request] 1. A part of the pressure fluid is provided by providing an orifice in the supply passage for feeding the pressure fluid discharged from a pump to a fluid device, and opening a spool valve for controlling the flow rate by the differential pressure across the orifice. In a flow control valve device for recirculating fluid, a connector is provided at an opening end of a valve accommodating hole of the spool valve and has a pressure fluid supply passage hole at an outer end side to a fluid device, and a connector formed at an inner end side of the connector. Is slidably disposed in the large-diameter hole and the small-diameter cylindrical portion on the inner end side thereof is exposed in the valve accommodating hole, so that the connector outer circumference is provided between the small-diameter cylindrical portion and the large-diameter hole. And a restriction spool forming a restriction passage that restrictively communicates the pressure fluid supply passage that opens into the large-diameter hole from the portion, and the pressure fluid supply passage hole is formed from the inner end to the outer end of the restriction spool. In the middle of In addition to providing a fixed orifice part that constitutes a refining part, a variable orifice part that constitutes the orifice together with this fixed orifice part is provided on the outer end side of the large diameter hole of the connector so that opening and closing can be controlled by the movement of the limiting spool. A flow control valve device characterized by the above.