JPH10331998A - Flow control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flow control device that can attain sufficient energy saving when an actuator is in a nonoperating state and required operating oil pressure is low. SOLUTION: A spool valve 50 controlling to open/close a drain passage 19 so as to control the flow rate of operating oil led to a discharge passage 8 is composed of an inner spool 51 and an outer spool 52. The end part of a large diameter part 51a of the inner spool 51 is provided with a flange 57 with which the end part of a cylindrical part 52a of the outer spool 52 comes in contact. An opening 58 communicated with a first pressure chamber 15 is formed between the flange 57 and the end part of the cylindrical part 52 a of the outer spool 52. A low pressure chamber 56 is formed on the inner peripheral side of the outer spool 52, while a control spring 17 is made to act upon the inner spool 51. A spring member 66 for energizing the inner spool 51 to the first pressure chamber 15 side and energizing the outer spool 52 to the second pressure chamber 16 side is attached between the inner spool 51 and the outer spool 52.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow control device for use in a power steering device of an automobile, for controlling a flow rate of a pressure working fluid supplied from a power source to an actuator of the power steering device to a predetermined flow rate. .

[0002]

2. Description of the Related Art In a power steering apparatus which assists manual steering torque using a fluid as a working medium, a pump driven by an internal combustion engine mounted on a vehicle is used as a power source for supplying a working fluid to the power steering apparatus. Is often applied. However, in general, it is desired that the power steering device be able to acquire sufficient steering assisting force when the vehicle is running at a low speed or at a stop, in other words, when the internal combustion engine is driven at a low speed. At the time of rotation drive, from the viewpoint of steering stability,
Does not require much steering assistance. Therefore, a power source whose pump output increases in proportion to the rotation speed of the internal combustion engine cannot be applied as it is.

[0003] Therefore, usually, the power steering apparatus uses a flow rate of a working fluid (hydraulic oil) supplied to the power steering apparatus so that a sufficient power steering operation can be performed in an idling or low rotation range of the internal combustion engine. When the rotational speed of the internal combustion engine is increased to some extent, a flow rate control device that controls the flow rate limited by the orifice and returns the surplus oil to the oil storage tank is applied.

In recent years, the surplus oil flow rate has been increased at a neutral position of steering operation that does not require steering assisting force,
There has been proposed a flow control device that reduces the amount of oil supplied to a power steering device, thereby reducing the amount of work performed by a pump and achieving energy saving.

As a flow control device of this type, for example, Japanese Patent Application Laid-Open No. 6-8840 discloses a spool valve slidably housed in a spool valve housing hole, and a first pressure chamber and a second pressure chamber are formed in the spool valve housing hole. Two pressure chambers are defined, and in the first pressure chamber,
An introduction passage communicating with the discharge passage through the control orifice and a drain passage communicating with the low pressure side are opened, and the pressure of the discharge passage is introduced into the second pressure chamber and the spool valve is biased toward the first pressure chamber. A control spring is accommodated to guide the required flow rate of hydraulic oil from the introduction path to the discharge path via the control orifice, and excess oil corresponding to the required flow rate is returned to the drain path controlled to be opened and closed by the movement of the spool valve. A bypass valve responsive to the pressure of the discharge passage, wherein when the pressure on the discharge passage side drops at a neutral position of the steering operation (the power steering device is not operated) by the bypass valve, The second pressure chamber communicates with the low pressure side to increase the opening area of the drain passage by the spool valve and supply the power to the power steering device. Flow control apparatus that reduce the amount are disclosed.

[0006]

In such a conventional example, the second pressure chamber communicates with the low pressure side by the bypass valve, thereby moving the spool valve which controls the flow rate, and thereby the oil amount in the discharge passage. Is to be reduced.

The pressure in the discharge passage is guided into the second pressure chamber as described above. That is, since the pressure after passing through the control orifice is guided, when the second pressure chamber communicates with the low pressure side, the hydraulic oil after passing through the control orifice drains to the low pressure side. Therefore, even when the power steering device (actuator) is in a non-operating state, a part of the hydraulic oil passes through the control orifice having the flow resistance. For this reason, the pump needs to maintain a predetermined discharge pressure in order for the hydraulic oil to pass through the control orifice, so that the pump performs wasteful work and energy saving cannot be sufficiently achieved. There is a fear.

The present invention has been devised in view of such a conventional situation, and suppresses wasteful energy consumption of a pump when an actuator is in a non-operating state and a required operating oil pressure is low. It is an object of the present invention to obtain a flow control device capable of sufficiently achieving energy saving.

[0009]

Therefore, according to the present invention, a spool valve is slidably housed in a spool valve housing hole, and a first pressure chamber and a second pressure chamber are formed in the spool valve housing hole.
An inlet passage and a drain passage communicating with the discharge passage through a control orifice are opened in the first pressure chamber, and the pressure in the discharge passage is guided into the second pressure chamber and the spool valve is formed in the second pressure chamber. And a control spring biasing the first pressure chamber toward the first pressure chamber to guide the required flow rate of hydraulic oil from the introduction path to the discharge path via the control orifice, and to transfer the excess oil to the required flow rate by moving the spool valve. In the flow rate control device for returning to the drain passage controlled to be opened and closed by the drain valve, the spool valve has a bottomed cylindrical outer spool having a through hole at the bottom, and a large-diameter portion inserted into the inner periphery of the cylindrical portion of the outer spool. An inner spool having a small-diameter portion inserted into the through-hole, and a flange in which the end of the cylindrical portion of the outer spool is in contact with the end of the large-diameter portion of the inner spool. An opening communicating with the first pressure chamber is formed between the flange and the end of the cylindrical portion of the outer spool, and a low-pressure chamber is formed between the inner periphery of the outer spool cylindrical portion and the outer periphery of the small-diameter portion of the inner spool. On the other hand, the bottom portion of the outer spool is arranged to face the second pressure chamber, the control spring acts on the inner spool, and the inner spool is moved between the inner spool and the outer spool by the first spool.
A spring member for urging the outer spool toward the second pressure chamber and urging the outer spool toward the second pressure chamber is attached.

[0010] The invention according to claim 2 is the configuration according to claim 1 in which the spring member is housed in the low-pressure chamber.

According to a third aspect of the present invention, in the configuration of the first aspect, an opening communicating with the first pressure chamber formed between the flange and the end of the cylindrical portion of the outer spool is provided. And a notch formed at the end of the cylindrical portion of the outer spool.

According to a fourth aspect of the present invention, in the configuration of the first aspect of the present invention, the opening communicating with the first pressure chamber formed between the flange and the end of the cylindrical portion of the outer spool is provided. , A through hole formed in the flange.

According to a fifth aspect of the present invention, in the configuration of the first aspect, the opening communicating with the first pressure chamber formed between the flange and the end of the cylindrical portion of the outer spool is provided. , A notch formed in the flange.

According to a sixth aspect of the present invention, in the configuration of the first aspect of the present invention, an inner peripheral side of a portion where the end of the cylindrical portion of the outer spool is in contact with the flange communicates with the opening. It has a configuration in which an annular groove is formed.

According to a seventh aspect of the present invention, in the configuration of the sixth aspect, the annular groove is a peripheral groove formed on an outer periphery of a large diameter portion of the inner spool and / or a cylinder of the outer spool. It is configured to be formed by chamfering formed on the inner peripheral side of the end of the portion.

In such a configuration, the hydraulic oil discharged from the pump is guided into the first pressure chamber through the introduction passage. The hydraulic oil introduced into the first pressure chamber is generated only when the restricted flow through the control orifice and when the drain passage is released by the movement of the spool valve based on the differential pressure across the control orifice. The excess oil flows from the first pressure chamber to the pump suction chamber and the oil storage tank through the drain passage to the oil storage tank. As a result, the required amount of hydraulic oil is guided to the actuator from the discharge passage under the restriction of the control orifice. For example, in a power steering device, a necessary steering assist force is obtained.

Here, in the present invention, the spool valve includes an inner spool and an outer spool, and between the inner spool and the outer spool, the inner spool is biased to the first pressure chamber. A spring member for urging the outer spool toward the second pressure chamber is attached, and the control spring acts on the inner spool. Thus, when the pressure in the first pressure chamber and the pressure in the second pressure chamber are low, the outer spool is in a position urged toward the second pressure chamber by a spring member attached thereto, and the spool valve is connected to the control orifice. The flow rate is controlled by the pressure difference between the front and rear and the spring force of the control spring. When the pressure in the first pressure chamber and the pressure in the second pressure chamber are high, the outer spool moves toward the second pressure chamber against the spring force of the spring member due to the pressure in the second pressure chamber and moves to a predetermined position. At that position, the spool valve controls the flow rate at that position.

That is, when the pressure in the first pressure chamber is low, that is, when the internal pressure of the pump is low, the outer spool is at a position urged by the spring member toward the second pressure chamber. The spool valve is formed integrally with the spool. Therefore, the spool valve moves based on the spring force of the control spring and the differential pressure across the control orifice, and the flow rate passing through the control orifice is A in FIG.
The flow rate is controlled to be indicated by -B.

Next, when the pressure in the first pressure chamber increases, the flow rate passing through the control orifice also increases, and the pressure in the discharge passage also increases. Therefore, the pressure in the second pressure chamber into which the pressure in the discharge passage is led increases. When the pressure in the second pressure chamber increases and exceeds the spring force of the spring member, the outer spool moves toward the first pressure chamber to a position where the spring force of the spring member balances the pressure in the second pressure chamber,
Reduce the opening area of the drain passage. As the opening area of the drain passage becomes smaller, the differential pressure across the control orifice increases accordingly, so that the spool valve opposes the second pressure chamber against the spring force of the control spring to keep this differential pressure constant. To control the flow rate at a position where the differential pressure across the control orifice and the spring force of the spring member and the control spring are balanced. Thereby, the flow rate passing through the control orifice is controlled to the flow rate indicated by B-C in FIG.

When the pressure in the first pressure chamber and the pressure in the second pressure chamber reach a predetermined pressure, the outer spool presses and compresses the spring member most and comes closest to the first pressure chamber side. It will come into contact with the flange of the inner spool. In this state, the spool valve controls the flow rate in response to the pressure difference between the control spring and the control orifice, and the flow rate passing through the control orifice is C- in FIG.
The flow rate is controlled at D. This flow rate is the maximum flow rate supplied to the actuator, and is usually controlled to this flow rate.

On the other hand, when the actuator is not operated (for example, in a neutral position of the power steering device),
Since the operating pressure of the discharge passage decreases, the pressure of the second pressure chamber also decreases. For this reason, the spool valve moves toward the second pressure chamber against the spring force of the control spring in the second pressure chamber in order to keep the differential pressure across the control orifice constant, increasing the opening area of the drain passage. . Thereby, most of the hydraulic oil introduced into the first pressure chamber from the introduction passage flows into the drain passage, and the pump internal pressure (discharge pressure)
And the workload of the pump is reduced.

At the same time, when the pressure in the discharge passage decreases when the actuator is not operated and the pressure in the second pressure chamber decreases, the outer spool receiving the pressure in the second pressure chamber is connected to the outer spool. It moves to the second pressure chamber side by the spring force of the attached spring member.

Therefore, the above-mentioned spool valve, which is composed of a double spool inside and outside, is provided with a differential pressure across the control orifice, ie, the pressure in the first pressure chamber and the pressure in the second pressure chamber plus the force obtained by adding the spring force of the control spring. When the outer spool is in the position to balance, the opening area of the drain passage opened by the spool valve is further increased by the movement of the outer spool toward the second pressure chamber.

Accordingly, the hydraulic oil supplied to the first pressure chamber is supplied to the pump suction side and the oil storage tank via the drain passage having an increased opening area when the actuator does not require the hydraulic oil. It is refluxed. For this reason, the pump that discharges the hydraulic oil to the first pressure chamber through the introduction passage has a reduced discharge pressure, thereby reducing the amount of work, and advantageously achieving energy saving.

In this case, the outer spool moves by the balance between the spring member attached to the outer spool and the pressure in the second pressure chamber, and changes the opening area of the drain passage. Therefore, since part of the pump discharge oil does not pass through the control orifice to move the outer spool, it is not necessary to maintain the pump discharge pressure at a predetermined pressure, and wasteful energy consumption of the pump is prevented. And energy saving can be achieved.

The outer spool moves from the state where the end of the cylindrical portion of the outer spool is in contact with the flange of the inner spool to the second pressure chamber side by the spring force of a spring member attached to the outer spool. When trying to do so, there is a possibility that both will adhere unintendedly on the contact surface and cause a so-called blocking phenomenon, causing a delay in operation. In the present invention, the flange and the end of the cylindrical portion of the outer spool are provided. This is advantageously solved by the pressure of the first pressure chamber being led to the opening formed between the first pressure chamber and the first pressure chamber.

That is, the pressure in the first pressure chamber, which is the same as the pressure acting on the end face of the inner spool on the first pressure chamber side, is guided to the portion where the opening is formed. The substantial contact area with the end is reduced, the adhesion at the contact surfaces of the two is prevented, and the operation delay due to the adhesion is prevented.

In particular, according to the invention as set forth in claims 6 and 7, since the pressure in the first pressure chamber is guided to the annular groove, the adhesion is further prevented.

[0029]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described.
An embodiment applied to a flow control device of a power steering device will be described in detail with reference to the drawings.

FIG. 1 is a sectional view of a flow control device showing an embodiment of the present invention. In the figure, 1 is a pump body 2
The housing 1 is provided with a spool valve housing hole 5 having one end sealed, and a pump cover 6 is provided on the open end side of the spool valve housing hole 5.

The pump cover 6 is provided with a discharge passage 8 communicating with a power steering device, that is, an actuator 7, and a control orifice 9 is formed in the discharge passage 8. In addition, an introduction passage 20 for guiding oil discharged from the pump 10 is formed in the pump cover 6.

A spool valve 50 comprising an inner spool 51 and an outer spool 52 is provided in the spool valve receiving hole 5.
Is slidably fitted, and the spool valve 50 is
The inside of the spool valve housing hole 5 is defined as a first pressure chamber 15 and a second pressure chamber 16, and the first pressure chamber 1 is constantly controlled by the spring force of a control spring 17 housed in the second pressure chamber 16.
The drain passage 19 that is biased to the side 5 and is in a normal state and closes the drain passage 19 communicating with the oil storage tank 11 at the land portion 18 (specifically, the land portion of the outer spool 52). The first pressure chamber 15 defined by the spool valve 50 includes:
An introduction passage 20 for guiding oil discharged from the pump 10 is open.

Reference numeral 21 denotes a passage for guiding the load pressure of the actuator 7, and this passage 21 communicates with the second pressure chamber 16 via a pressure-sensitive orifice 23.

Reference numeral 34 denotes a relief valve provided in the passage 21, which detects an excess pressure in the discharge passage 8 which is guided into the second pressure chamber 16 through the passage 21 and the pressure-sensitive orifice 23.
This is avoided by the relief operation of the relief valve 34.

As described above, the spool valve 50 includes an inner spool 51 and an outer spool 52. The outer spool 52 has a bottomed cylindrical shape as a whole and has a through hole 53 in a bottom portion 52b. A large-diameter portion 51a inserted into the inner periphery of the cylindrical portion 52a of the outer spool 52,
Similarly, the outer spool 52 has a small diameter portion 51b to be inserted into the through hole 53. The cylindrical portion 52a of the outer spool 52 faces the first pressure chamber 15, and the bottom portion 52b faces the second pressure chamber 16. is there.

The outer spool 52 is formed with a circumferential groove 54 communicating with the drain passage 19 and a diametrical through-hole 55 opening at the bottom of the circumferential groove 54. Inner circumference and the inner spool 5
A low-pressure chamber 56 communicating with the drain passage 19 through the through hole 55 is formed between the small-diameter portion 51b and the outer periphery of the small-diameter portion 51b.

At the end of the large diameter portion 51a of the inner spool 51, there is formed a flange 57 with which the end of the cylindrical portion 52a of the outer spool 52 contacts.
An opening 58 communicating with the first pressure chamber 15 is formed between the outer spool 52 and the end of the cylindrical portion 52 a of the outer spool 52. In this embodiment, the opening 58 is formed with a notch 59 formed at the end of the cylindrical portion 52a of the outer spool 52, as best shown in FIG.

The outer spool 5 is attached to the flange 57.
A circumferential groove 6 formed on the outer periphery of the large diameter portion 51a of the inner spool 51 is provided on the inner peripheral side of the portion where the end of the second cylindrical portion 52a contacts.
An annular groove 62 communicating with the opening 58 is formed by a chamfer 61 formed on the inner peripheral side of the end of the cylindrical portion 52 a of the outer spool 52. In this embodiment, the circumferential groove 60 also functions as a clearance groove for processing the large diameter portion 51a of the inner spool 51 with high precision.
Also functions as a guide when the inner spool 51 is inserted into the outer spool 52.

The annular groove 62 is provided on the inner spool 5.
One of the peripheral groove 60 formed on the outer periphery of the large diameter portion 51a and the chamfer 61 formed on the inner peripheral side of the end of the cylindrical portion 52a of the outer spool 52 may be formed. The groove 62 itself can be eliminated.

Reference numeral 63 denotes a small diameter portion 51 of the inner spool 51.
b is a spring receiving member for supporting the control spring 17. The spring receiving member 63 also serves as a stop member that regulates the maximum movement position of the outer spool 52 toward the second pressure chamber 16.
A through hole 64 is formed at a position where b contacts.

Reference numeral 65 denotes an attachment bolt for attaching the spring receiving member 63 to the end of the small diameter portion 51b of the inner spool 51.

Reference numeral 66 denotes a spring member disposed between the inner spool 51 and the outer spool 52. The spring member 66 is housed in the low-pressure chamber 56,
1 to the first pressure chamber 15 side, and the outer spool 52
To the second pressure chamber 16 side.

According to such a configuration, the discharge oil of the pump 10 guided from the introduction passage 20 into the first pressure chamber 15 is:
It is guided from the discharge passage 8 to the actuator 7 through the control orifice 9, and the actuator 7 performs a predetermined operation.

At this time, in a normal state, the spool valve 50 constituted by the inner and outer double spools has its bottom 5
2b abuts on a spring receiving member 63 also serving as a stop member, the control spring 17 controls the first pressure chamber 15
Side, and the drain passage 19 is closed by a body portion (land portion) 18, and the entire amount of the pump discharge oil introduced into the first pressure chamber 15 is supplied to the actuator 7 through the control orifice 9. Be guided.

On the other hand, when the rotation speed of the pump 10 increases and the discharge oil amount of the pump 10 increases, and the discharge oil amount of the pump 10 introduced into the first pressure chamber 15 increases, the control orifice 9 The hydraulic oil in the first pressure chamber 15 is guided to the discharge passage 8 under the flow, and the spool valve 50 moves rightward as shown in the drawing based on the pressure difference between the control orifice 9 and the control spring 17. Is compressed to a predetermined length to open the drain passage 19, and excess oil is returned to the oil storage tank 11 from the drain passage 19.

Here, in the present invention, the spool valve 50 is composed of an inner spool 51 and an outer spool 52, and the inner spool 51 is connected between the inner spool 51 and the outer spool 52 by the first pressure. A spring member 66 that urges the chamber 15 side and urges the outer spool 52 toward the second pressure chamber 16 is attached, and the control spring 17 acts on the inner spool 51. Thereby, the first
When the pressure in the pressure chamber 15 and the pressure in the second pressure chamber 16 are low, the outer spool 52 is urged toward the second pressure chamber 16 by the spring member 66, and the bottom portion 52 b contacts the stop member 63 and stops. The spool valve 50 compresses the control spring 17 to a predetermined length (L1), moves based on the spring force of the control spring 17 and the differential pressure across the control orifice 9, and controls the flow rate (FIG. 1).

When the pressures in the first pressure chamber 15 and the second pressure chamber 16 are high, the outer spool 52
The pressure in the pressure chamber 16 causes the spring member 66 to move toward the first pressure chamber 15 against the spring force of the spring member 66 (see FIG. 2). (See FIG. 3). Therefore,
Since the relative position between the spool valve 50 and the drain passage 19 changes due to the movement of the outer spool 52, the spool valve 50 further compresses the control spring 17 (dimension L2). Second to force
It moves by the balance between the force obtained by adding the force due to the pressure in the pressure chamber 16 and the force obtained by adding the spring force of the spring member 66 to the force generated by the pressure in the first pressure chamber 15, and controls the flow rate.

That is, when the pressure in the first pressure chamber 15 is low, that is, when the internal pressure of the pump 10 is low, the outer spool 52 is in a position urged by the spring member 66 toward the second pressure chamber 16. In this state, the spool valve 50 is formed integrally with the inner spool 51. Therefore, the spool valve 50 moves based on the spring force of the control spring 17 and the differential pressure across the control orifice 9, and the flow rate passing through the control orifice 9 is controlled to the flow rate indicated by AB in FIG.

Next, when the pressure in the first pressure chamber 15 increases, the flow rate passing through the control orifice 9 also increases, and the pressure in the discharge passage 8 also increases. Therefore, the discharge passage 8
The pressure in the second pressure chamber 16 to which the internal pressure is guided increases. When the pressure in the second pressure chamber 16 increases and exceeds the spring force of the spring member 66, the outer spool 52 applies the first pressure until the spring force of the spring member 66 balances the pressure in the second pressure chamber 16. Moves to the chamber 15 side, and the drain passage 1
9 has a smaller opening area. As the opening area of the drain passage 19 decreases, the differential pressure across the control orifice 9 increases accordingly, so that the spool valve 50 is pressed against the spring force of the control spring 17 to maintain this differential pressure constant. (2) Moves to the pressure chamber 16 side, and controls the flow rate at a position where the differential pressure across the control orifice 9 and the spring force of the spring member 66 and the control spring 17 are balanced. Thus, the flow rate passing through the control orifice 9 is controlled to the flow rate indicated by B-C in FIG.

The inside of the first pressure chamber 15 and the second pressure chamber 16
When the internal pressure reaches a predetermined pressure, the outer spool 52 presses and compresses the spring member 66 most and approaches the first pressure chamber 15 side, and the end of the cylindrical portion 52 a of the outer spool 52 is brought into contact with the flange 57 of the inner spool 51. Will be in contact. In this state, the spool valve 50 controls the flow rate in response to the differential pressure between the control spring 17 and the control orifice 9, and the flow rate passing through the control orifice 9 is C in FIG.
The flow rate is controlled to be indicated by -D. This flow rate is the maximum flow rate supplied to the actuator, and is usually controlled to this flow rate.

On the other hand, when the actuator 7 is not operated, that is, when the power steering device is in the neutral position, the operating pressure of the discharge passage 8 is reduced, so that the pressure in the second pressure chamber 16 is also reduced. For this reason, the spool valve 50 is pressed against the spring force of the control spring 17 in the second pressure chamber 16 to maintain the differential pressure across the control orifice 9 constant.
It moves to the pressure chamber 16 side to increase the opening area of the drain passage 19. As a result, much of the hydraulic oil introduced into the first pressure chamber 15 from the introduction passage 20 flows into the drain passage 19, and the internal pressure of the pump 10 is reduced, and the work of the pump 10 is reduced. Will be.

At the same time, when the pressure in the discharge passage 8 decreases when the actuator 7 is not operated, the pressure in the second pressure chamber 16 also decreases. Thus, the outer spool 52 receiving the pressure in the second pressure chamber 16
Is moved toward the second pressure chamber 16 by the spring force of a spring member 66 attached to the outer spool 52, and the bottom portion 52a of the outer spool 52 is a spring receiving member 63 serving also as a stop member.
It will stop at the position where it abuts.

Therefore, the position where the spool valve 50 balances the pressure difference between the control orifice 9 and the pressure in the first pressure chamber 15 and the pressure in the second pressure chamber 16 plus the spring force of the control spring 17. The outer spool 5
The opening area of the drain passage 19 opened by the spool valve 50 further increases due to the movement of 2 toward the second pressure chamber 16 side.

Thus, the hydraulic oil supplied into the first pressure chamber 15 flows through the drain passage 19 whose opening area is increased by the movement of the outer spool 52 when the actuator 7 does not require the hydraulic oil. The oil is returned to the suction side of the pump 10 and the oil storage tank 11. For this reason, the pump 10 that discharges the hydraulic oil to the first pressure chamber 15 through the introduction passage 20 has a reduced discharge pressure, reduces the amount of work, and advantageously achieves energy saving.

In this case, the outer spool 52 moves by the balance between the spring member 66 attached to the outer spool 52 and the pressure in the second pressure chamber 16, and changes the opening area of the drain passage 19. Therefore, since a part of the discharge oil of the pump 10 does not pass through the control orifice 9 in order to move the outer spool 52,
It is not necessary to maintain the discharge pressure of the pump 10 at a predetermined pressure, and it is possible to suppress wasteful energy consumption of the pump 10 and achieve energy saving.

Further, the outer spool 52 is formed such that an end of the cylindrical portion 52a of the outer spool 52 is
When it is attempted to move toward the second pressure chamber 16 by the spring force of the spring member 66 attached to the outer spool 52 from the state in which the outer spool 52 is in contact with the flange 57, the two adhere to each other against the contact surface. In the present invention, where a so-called blocking phenomenon may occur and an operation delay may occur, in the present invention, the opening 58 formed between the flange 57 and the end of the cylindrical portion 52a of the outer spool 52 is provided. In this case, the pressure in the first pressure chamber 15 is guided to the annular groove 62 communicating with the opening 58, so that this is advantageously solved.

That is, the inner spool 51 is provided in the portion where the opening 58 is formed and the annular groove 62 communicating with the opening 58.
The same as the pressure acting on the end face of the first pressure chamber 15 side.
Since the pressure in the pressure chamber 15 is guided, the substantial contact area between the flange 57 and the end of the cylindrical portion 52a of the outer spool 52 is reduced, and the adhesion at the contact surfaces of both is prevented,
The operation delay caused by the adhesion is prevented. As a result, the control flow rate is not disturbed due to the operation delay of the spool valve 50, and smooth flow control is achieved.

The outer spool 52 is connected to the inner spool 5.
By configuring the spool valve 50 with the dual structure of the inside and the outside, the flow control valve does not become particularly long.

FIGS. 6 to 9 show another embodiment of the present invention. This embodiment is different from the above embodiment in that the flange 57 of the inner spool 51 and the cylindrical portion of the outer spool 52 are different from each other. 52a and between the end of the
An opening 58 communicating with the first pressure chamber 15 is formed by a through hole 67 formed in the flange 58. Although one through-hole 67 is provided in this embodiment, a plurality of through-holes may be provided. Since other configurations are the same as those of the above-described embodiment, the same components are denoted by the same reference numerals, and the duplicate description will be omitted.

With such a configuration, the same operation and effect as described in the above embodiment can be obtained.

FIGS. 10 to 13 show still another embodiment of the present invention. This embodiment is different from the above embodiment in that the flange 5 of the inner spool 51 is provided.
An opening 58 communicating between the first pressure chamber 15 and the opening 58 formed between the outer peripheral spool 52 and the end of the cylindrical portion 52 a of the outer spool 52 is formed by a notch 68 formed in the flange 58. Although one notch 68 is provided in this embodiment, a plurality of notches may be provided. Since other configurations are the same as those of the above-described embodiment, the same components are denoted by the same reference numerals, and the duplicate description will be omitted.

With such a configuration, the same operation and effect as described in the above embodiment can be obtained.

Although the embodiment has been described with reference to the drawings, the specific configuration is not limited to this embodiment, and can be changed without departing from the spirit of the invention.
For example, regarding the structure in which the spring member 66 is disposed in the low-pressure chamber 56, the spring member is disposed between the inner spool 51 and the outer spool 52, and the inner and outer spools 51 and 52 are attached to each other in opposite directions. Because it is a force
It is also possible to arrange between the end of the cylindrical portion 52 a of the outer spool 52 and the flange 57.

[0064]

As described above in detail, according to the present invention, when the actuator is in the non-operating state and the required hydraulic oil pressure is low, it is possible to suppress unnecessary energy consumption of the pump. it can. Therefore, a flow control device capable of sufficiently achieving energy saving can be obtained.

Further, adhesion between the flange of the inner spool and the end of the cylindrical portion of the outer spool is prevented, and smooth flow control is achieved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a flow control device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a process in which the pressures in a first pressure chamber and a second pressure chamber gradually increase from the state shown in FIG. 1 and the spool valve moves toward the second pressure chamber.

FIG. 3 is a cross-sectional view showing a state where the pressures in the first pressure chamber and the second pressure chamber are higher than the state shown in FIG. 1 and the spool valve has moved to the second pressure chamber side.

FIG. 4 is a plan view of the spool valve shown in FIG. 1;

FIG. 5 is a diagram showing flow control characteristics.

FIG. 6 is a view similar to FIG. 1, illustrating a flow control valve according to another embodiment of the present invention.

FIG. 7 is a side view of the spool valve shown in FIG. 6;

FIG. 8 is a view similar to FIG. 2, showing an operation state of the flow control valve shown in FIG. 6;

FIG. 9 is a view similar to FIG. 3, showing an operation state of the flow control valve shown in FIG. 6;

FIG. 10 is a drawing similar to FIG. 1 of a flow control valve showing another embodiment of the present invention.

FIG. 11 is a side view of the spool valve shown in FIG. 10;

FIG. 12 is a view similar to FIG. 2, showing an operation state of the flow control valve shown in FIG. 10;

FIG. 13 is a view similar to FIG. 3, showing an operation state of the flow control valve shown in FIG. 10;

[Explanation of symbols]

 Reference Signs List 5 spool valve receiving hole 8 discharge passage 9 control orifice 15 first pressure chamber 16 second pressure chamber 17 control spring 19 drain passage 20 introduction passage 50 spool valve 51 inner spool 51a large diameter portion 51b small diameter portion 52 outer spool 52a cylindrical portion 52b Bottom 53 Through-hole 56 Low-pressure chamber 57 Flange 58 Opening 66 Spring member

Claims (7)

[Claims] A spool valve is slidably housed in a spool valve housing hole, and a first pressure chamber and a second pressure chamber are defined in the spool valve housing hole, and a control orifice is provided in the first pressure chamber. And a control spring for guiding the pressure of the discharge passage and biasing the spool valve toward the first pressure chamber in the second pressure chamber. A flow control device that guides a required flow rate of hydraulic oil from the introduction path to a discharge path through a control orifice, and returns excess oil to the required flow rate to a drain path that is opened and closed by movement of the spool valve. A spool valve, a bottomed cylindrical outer spool having a through hole at the bottom, an inner spool having a large diameter portion inserted into the inner periphery of the cylindrical portion of the outer spool, and a small diameter portion inserted into the through hole A flange, at the end of the large-diameter portion of the inner spool, which is in contact with the end of the cylindrical portion of the outer spool, and a first pressure between the flange and the end of the cylindrical portion of the outer spool. An opening communicating with the chamber is formed, and a low-pressure chamber is formed between the inner periphery of the cylindrical portion of the outer spool and the outer periphery of the small-diameter portion of the inner spool, while the bottom of the outer spool faces the second pressure chamber. The control spring acts on the inner spool, and further, between the inner spool and the outer spool, the inner spool is urged toward the first pressure chamber, and the outer spool is urged toward the second pressure chamber. A flow control device, comprising a spring member to be attached. 2. The flow control device according to claim 1, wherein the spring member is housed in the low-pressure chamber. 3. An opening communicating with the first pressure chamber formed between the flange and the end of the cylindrical portion of the outer spool is a notch formed in the end of the cylindrical portion of the outer spool. The flow control device according to claim 1, wherein 4. An opening formed in the flange and an end of the cylindrical portion of the outer spool and communicating with the first pressure chamber is a through hole formed in the flange. Flow control device. 5. An opening, which is formed between the flange and the end of the cylindrical portion of the outer spool and communicates with the first pressure chamber, is a notch formed in the flange. Flow control device. 6. The flow rate according to claim 1, wherein an annular groove communicating with the opening is formed on an inner peripheral side of a portion where the end of the cylindrical portion of the outer spool contacts the flange. Control device. 7. The annular groove is formed by a circumferential groove formed on the outer periphery of the large diameter portion of the inner spool and / or a chamfer formed on an inner circumferential side of an end of the cylindrical portion of the outer spool. The flow control device according to claim 6, wherein