JPS62220787A - Flow control valve - Google Patents

Abstract

PURPOSE:To enable the non-return drooping characteristics of a pump to be obtained while permitting the device to be simple in construction by providing a union with an orifice which causes a spool valve to open, and then placing on the union a sleeve, having a restricted passage on its outer surface, so that it may be free to slide. CONSTITUTION:When the speed of rotation of a pump is gradually increased, the discharge rate of flow increases, and a spool valve 3 begins to move to the left due to the differential pressure across a fixed orifice 4d and orifices 4g, 4h, and accordingly, the rate of flow supplied to power steering apparatuses P, S is kept almost constant. When the speed of rotation thereof is increased furthermore, then, the differential pressure across a restricted passage 15 increases, the force causes a sleeve 13 to move to the left by resisting the energizing force of a spring 14.

Description

Detailed Description of the Invention [Industry - Second Field of Application] The present invention relates to a flow rate control valve, and is particularly applicable to hydraulic equipment due to the drooping characteristic (drooping) of the flow M, that is, the increase in pump discharge flow rate. This invention relates to a flow control valve having a so-called non-return drooping characteristic, which has a characteristic that the flow rate supplied to the hydraulic equipment decreases, and which has a so-called non-return drooping characteristic, which prevents the supply flow rate from returning due to the influence of pressure fluctuations in hydraulic equipment.

[Conventional technology]

Flow control valves with the above characteristics are generally used in vehicle power steering systems to help stabilize the vehicle during high-speed running and reduce horsepower consumption. An orifice is provided in the supply passage that supplies the pressurized fluid to the hydraulic equipment, and the differential pressure before and after the orifice opens the spool valve to recirculate a portion of the pressure fluid. It is conventionally known that the orifice is reduced by a control spool that responds to the pressure difference before and after the restriction passage.
8 [Publication No. 1, Japanese Unexamined Patent Publication No. 57-44Ete, etc.).

However, all of the meteor control valves according to the configuration described in item 1-1 have a complicated structure and a large number of parts, requiring manufacturing precision, and it is also difficult to tune the characteristics.

Therefore, the inventors of Woodland placed a cylindrical union in the hole of the housing as a control valve in order to obtain the drooping characteristic with an extremely simple structure and have good assembly. In addition to forming an orifice for opening the spool valve, the sleeve is slidably fitted to the union to form a restriction passage between the outer peripheral surface of the sleeve and the inner surface of the housing hole, and is further provided at one end of the union. proposed a structure in which a spring is disposed between the retainer and the end face of the sleeve (Japanese Patent Application No. 60-0630
No. 01).

[Problems to be Solved by the Invention] However, although the flow control valve according to the configuration described in -1- was able to achieve the purpose of obtaining non-return drooping characteristics with a simple structure, A groove is formed in the union as one seat surface for the rotation, and the retainer ring is installed in this groove, so the
Some problems remained in terms of the number of parts, number of parts, etc.

The present invention has been developed in view of the above points, and has an extremely simple structure and non-return drooping. It is an object of the present invention to provide a flow control valve which can obtain good ν properties, reduce processing steps and the number of parts, and further improve assemblability.

[Means for solving problems]

The flow control valve according to the present invention has a cylindrical union disposed in the hole of the housing, and the spool valve is opened in the union.
At the same time, the sleeve is slidably fitted into the union to form a restriction passage on the outer surface of the sleeve, and a spring is disposed between the flange provided at one end of the union and the end surface of the sleeve. It was established.

[Effect]

The flow control valve according to the present invention does not require grooving of the union or retaining ring, and also improves assemblability and reliability.

〔Example〕

The present invention will be explained below based on illustrated embodiments.

FIG. 1 shows a flow control valve according to an embodiment of the present invention, in which a spool valve housing hole (2) with a large diameter on the opening side is formed in a pump housing (1). )
A spool valve (3) is housed in the small diameter part (2a) of the connector (10), and a cylindrical valve (3) is housed in the large diameter part (2b). Union (4)
is inserted, and this union (4) is connected to the connector (1
0) is fixed in the valve housing hole (2) by screwing it into the housing (1). Large diameter part of valve storage hole (2) (
2b) communicates with the pump (6) via the supply channel (5), and the small diameter section (2a) communicates with the tank (8) via the return channel (7). The spool valve (3) is urged toward the large diameter portion (2b) by the spring (9) and stops when it hits the tip of the union (4), thereby establishing communication between the supply path (5) and the return path (7). It's blocked.

The cylindrical union (4) is located near the spool valve (3), and its interior is divided into a chamber (4a) on the spool, +1/valve side and a chamber (4b) on the connector (10) side. Bulkhead (4c
) are provided, and these compartments (4a) and (4N are communicated by a fixed orifice (4d) formed in the partition wall (4c). Also, the partition 1D4c of the union (4))
The part closer to the spool valve (3) is the connector (lO
) has a larger diameter than the part closer to the valve housing hole (4), and this part has a communication hole (4) that communicates the inside of the valve storage hole (2) with the inside of the chamber (4a).
e), but also a pair of orifices (4g) at different axial positions near the partition wall (4c) of the small diameter portion (4f).
, (4h) is blurred.

Therefore, the supply passage (5) flows through the valve storage hole (2), through the communication hole (4e), the chamber (4a), the fixed orifice (4d), and through both orifices (4g) and (4h). It communicates with the chamber (4b) in the small diameter portion (4f) of the union (4), and further communicates with the passageway (1) in the shaft center of the connector (10).
0a) to the power steering device (P, S,). In addition, the connector passage (10a) is connected to the connector (10a).
The spring (9) is communicated with the chamber (11) containing the spring (9) through a radial passage (10b) formed in the housing (0) and a communication passage (not shown) formed in the housing. , When the flow rate of the pressure oil discharged from the pump (6) exceeds a certain value, the differential pressure before and after the fixed orifice (4d) and the orifice (4K), (4h) will cause the spool valve (3
) and when it overcomes the spring (9), moves the spool valve (3) to the left in the figure. Pump (6)
A part of the pressure oil supplied from the tank (8) can be returned to the tank (8).

A sleeve (+3) is slidably fitted around the outer periphery of the small diameter portion (4f) of the union (4). This sleeve (
13) has a large-diameter cylindrical portion (13a) formed at the end on the spool valve (3) side that extends toward the spool valve, and the sleeve (13) is attached to the bottom surface of this cylindrical portion (+3a). The connector (10) is biased toward the connector (10) by the spring (14) disposed between the flange (4 electric) formed at the end of the union (4) on the spool valve (3) side.
) and stops when it comes into contact with the bottom of the annular groove (10c) formed on the end surface! The outer peripheral surface of the large diameter cylindrical part (+3a) of the sleeve (13) is
The spool valve (3) has an outer diameter portion (+3b) of the passenger ship and a tapered portion (13c) whose outer diameter gradually decreases toward the connector (10). This large diameter cylinder Jkrffl
A gap (15) is formed between the outer circumferential surface of (13a) and the inner circumferential surface of the valve housing hole (2), and this gap (15) is defined by the flow rate of pressure oil supplied from the oil pump (8). It constitutes a restriction passage that restricts. Therefore, the oil pump (6)
When the amount of oil supplied from the
5) The sleeve (13) is moved toward the spool valve (3) (to the left in the figure) against the spring (14) due to the pressure difference between the front and rear sides.

The above pair of orifices (4g) and (4h) are the sleeve (+3) crab l connector (10) (7) CJJ
Sl+I'i (IOc) It is opened when it hits the bottom surface and stops, and is sequentially closed by this sleeve (13) when the sleeve (13) moves, and acts as a 1r transformation orifice. It looks like this.

Then, the small diameter part (2a) of the large diameter part (2b) of the valve storage hole (2)
), that is, the spool valve of the union (4) (
3) A pair of orifices (4g), (4h) from the side end
An enlarged diameter portion (2d) is formed around the portion that reaches ).

To explain the operation of the flow control valve configured as above, in the low speed rotation range (low flow range) of the pump (6) driven by the vehicle engine, the spool valve (3) is controlled by the force of the spring (9). The sleeve (13) is in contact with the union (4) and blocks the supply path (5) and the return path (7), and the sleeve (13) is also connected to the connector (10) by the spring (14).
) and comes to a stop when it hits the bottom of the annular groove (10c). Therefore, the entire amount of pressure oil discharged from the pump (6) is used by the power steering system! ! (P, S,).

Next, as the pump rotation speed gradually increases, the discharge flow rate increases and the fixed orifice (4d) and orifice (
4g), (4h) The spool valve (
3) begins to move to the left, and the surplus flow where the recirculation path (7) communicates with the supply path (5) side is recirculated, and the power steering device (P, S,)
The flow rate supplied to is kept approximately constant.

Furthermore, when the pump rotation speed increases by -1, the pressure difference across the restriction passage (15) increases, and this force overcomes the old force of the spring (14) to move the sleeve (13) to the left. As a result, the sleeve (13) first begins to throttle the first orifice (4g) and then gradually also the second orifice (4h), causing the power steering device (P, S,
While gradually decreasing the amount of oil supplied to the orifices, the pressure difference before and after the orifices (4g) and (4h) increases, causing the spool valve (3) to move further to the left and increasing the recirculation amount. By reducing the amount of oil supplied to the power steering device 51 (P, S,) in this way, the high-speed stability of the vehicle can be improved and the horsepower consumption during high-speed running can be reduced.

When the pump rotation speed further increases and the discharge flow rate from the pump (6) shows a further increase, the sleeve (13
) further goes to the left, and the enlarged diameter part (2d) of the valve storage hole (2)
When it reaches the inside, the restriction passage, that is, the gap (15) is rapidly expanded, and an increase in the pressure difference between the downstream side and the downstream side of the restriction passage (15) is suppressed. Therefore, the effect of reducing the horsepower consumption can be obtained without placing an unnecessary load on the pump (6).

When the discharge flow rate from the pump (6) continues to increase further, the sleeve (13) moves further to the left, and the sleeve (13)
The bottom surface of the large-diameter cylindrical part (+3a) of the union (4) comes into contact with the stepped part (4j) between the large-diameter part and the small-diameter part of the union (4), and the sleeve (13) stops moving more than necessary. Regulated.

Even if pressure fluctuation occurs in the hydraulic equipment (power steering device (P, S,)) when the sleeve (13) moves to the left, the restriction passage (
There is no change in the flow rate flowing through the restriction passage (15).
5) The pressure difference before and after does not change, so the sleeve (13)
The hydraulic equipment (power steering device ff (P, S,
)) does not change.

As described above, according to this embodiment, the sleeve (13) fitted around the outer periphery of the union (4) and the hole (2) of the housing (1) are combined.
), and the sleeve (13) is moved by the pressure difference before and after the restriction passage to gradually narrow the orifices (4g) and (4h). Furthermore, since the union (4), sleeve (13), and spring (14) are assembled as an integrated subassembly, it is possible to obtain highly reliable flow 111 control without any assembly errors. I can do it. In addition, since the spring (14) is installed at the tip of the union (4), the only amount of pressure oil that passes between the windings of the spring (14) is the adjusted flow rate sent to the power steering system Pi (P, S,). Therefore, especially when the sleeve (13) moves and bends the spring (14), the pressure loss is small and the effect on the characteristics is small, so the axial length of the spring (14) can be shortened and the entire spring (14) can be bent. It is also possible to make it more compact.

Also, unlike the conventional configuration, the flange (41) is integrally formed on the union (4) and serves as a fixed seating surface for the spring (14), reducing the number of parts to be machined and reducing costs. Moreover, it is possible to improve the assemblability and improve the reliability and strength.

Furthermore, in the conventional configuration, the number of parts is large, so the dimensions tend to vary, and the flow characteristics also vary widely.However, in this embodiment, the sleeve (13)
Both orifices (4g) are closed sequentially by the movement of
(4h) from the end of the flange (41) which is one spring seat.
), the respective distances (Lt') and (L2
) (see Figure 2) can be made smaller than in the conventional case where the retainer ring is fitted into the groove formed in the union. In contrast, in the case of this embodiment, the variation can be kept within the range of the solid line of the two trees, whereas the variation occurs within the range of the broken line.

Note that the shape of the sleeve (13) is not limited to that of the above embodiment, and may be any shape as long as a restriction passage is formed on the outer surface thereof.

〔Effect of the invention〕

As described above, according to the present invention, the flange is integrally formed on the union, and the sleeve is moved in one direction by the spring disposed between the sleeve fitted on the union and the second flange. Because it is biased, it is easier to assemble than conventional products, reduces processing steps and the number of parts, and reduces costs.It also improves reliability and strength, and also improves flow rate. Various effects such as being able to suppress variations in characteristics can be obtained.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional view showing a concentrated acid control valve according to an embodiment of the present invention, FIG. 2 is an enlarged sectional view of a union, and FIG. 3 is a variation in flow characteristics between the conventional configuration and the configuration of the present invention. FIG. (1)...housing, (3)...spool valve, (4)...union, r4i)...flange, (4g), (4h) orifice, (6)...
Pump, (13)... Sleeve, (14)...
... Spring, (15) ... Restriction passage, (p
,s,)...Hydraulic equipment.

Claims (1)

[Claims] In the flow control valve, an orifice is provided in the supply passage that supplies the pressure fluid discharged from the pump to the hydraulic equipment, and the spool valve is opened by the differential pressure across the orifice, and a part of the pressure fluid is recirculated. The formed cylindrical union is placed in the hole of the housing and fixed to the housing, and the sleeve is slidably fitted to the union, and the flange provided at one end of the union is connected to the end of the sleeve. A spring disposed between biases the sleeve in one direction to open the orifice when the sleeve is inactive, and the differential pressure between the upstream and downstream sides of the restriction passage formed on the outer surface of the sleeve is A flow control valve characterized in that the orifice is controlled to be reduced by sliding a sleeve.