JP3227582B2 - Cartridge type throttle valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cartridge type throttle valve.

[0002]

2. Description of the Related Art FIG.
The one shown at 0 is used. In the figure, a main throttle valve is constituted by a sleeve 1, a spool 2 and a cover 3, and a proportional electromagnetic throttle valve 4 is used as a pilot valve. The spool 2 is provided with a slit 5 as shown in FIG.
As shown in FIG. 1, a variable throttle section 6 is formed between the slit 5 and the upper edge of the sleeve 1. In the main throttle valve of the meter-out circuit, the main circuits A, B
Part of the fluid flows into the drain line 7 from the upper part of the spool 2 through the proportional electromagnetic type throttle valve 4 through the slit 5 and the variable throttle unit 6, and the rest flows through the main circuits A and B. It flows to the tank line 8. 7a is a drain tank, and 8a is an oil tank. The area of the ring-shaped surface 2a at the lower part of the spool 2 and the area of the surface 2b of the spool 2 which is in contact with the tank line 8 are both S, the upper surface 2c of the spool 2.
Is designed to be 2 × S. For this reason, the spool 2 is positioned at a position where the area of the variable throttle unit 6 formed by the slit 5 and the sleeve 1 matches the opening of the proportional electromagnetic throttle valve 4. Since the proportional electromagnetic throttle valve 4 is a valve that controls the opening in proportion to the input current, the main throttle valve can also control the throttle opening in proportion to the input current. In this example, the proportional electromagnetic throttle valve 4 is used as a pilot valve, but a throttle valve that is manually operated is also often used in general.

[0003]

However, the above-mentioned conventional cartridge type throttle valve has the following problems, and a countermeasure has been demanded in advance. (1) Since the surface 2b of the spool 2 which is in contact with the tank line 8 is affected by the pressure of the tank line 8, it is necessary to return the fluid L to the tank line 8 through a large flow path. Further, the movement of the spool 2 tends to be unstable, and vibration occurs when a large flow rate transiently flows through the tank line 8. (2) In FIG. 10, the fluid L flows from the left side of the spool 2 to the lower part of the spool 2, and the lower part of the spool 2 must be connected to the tank line 8. That is, the flow rate can be controlled only in one direction, and it must be connected to the tank line 8, so that it cannot be used for the meter-in circuit. (3) Since the area of the pressure receiving surface 2c of the spool 2 is large, it is necessary to increase the width of the slit 3 in order to use the drive with high response, and the pilot flow rate becomes large. (4) Since the main circuit is directly connected to the slit 2 of the spool 2, when the fluid of the main circuit is contaminated, the thin slit 5 is liable to be clogged by foreign matter in the fluid.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the conventional cartridge type throttle valve, and provides a cartridge type throttle valve having stable operation and high responsiveness and capable of bidirectional flow control. It is assumed that.

[0005]

In order to achieve the above object, in a cartridge type throttle valve according to the present invention, a pilot line separate from a main circuit is provided to provide an external pilot system, and a pilot line is provided through a central portion of a spool. Holes were drilled. A plurality of small holes were formed in parallel in the fluid passage to the slit.

[0006]

[Function] Since the external pilot system is used, it can be used for a meter-in circuit, and the main throttle valve can perform bidirectional flow control. Further, the area of the pressure receiving portion of the spool of the main throttle valve can be reduced, the pilot flow rate can be reduced, and the responsiveness can be improved. In addition, since a through hole is formed in the spool or a land is provided at the lower part of the spool, the force of the main circuit pressure applied to the spool is balanced, the fluid force is reduced, and the large flow rate control is stabilized. It can be performed, and the weight can be reduced.
Furthermore, the plurality of small holes formed in the flow path to the slit greatly reduces the adverse effect of the foreign matter in the fluid.

[0007]

【Example】

Embodiment 1 FIG. 1 is a sectional view of a cartridge type throttle valve showing an embodiment of the present invention, and FIG. 2 is a sectional view showing a slit. In the figure, the main throttle valve includes a sleeve 11, a spool 12, and a cover 13, and a proportional electromagnetic throttle valve 4 is used as a pilot valve. A slit 14 is formed in the spool 12 of the throttle valve to form a variable throttle portion 15 with the upper edge of the sleeve 11. A through hole 16 is formed in the center of the spool 12, and a pilot line C for guiding pressure from outside is formed separately from the main circuits A and B.
The lower surface 12a and the upper surface 12b of the spool 12 are ring-shaped and have the same area, but can be arbitrarily determined from the thickness of the spool 12 determined by the withstand pressure calculation from the working pressure.
Usually the minimum value. If this value is very small, the fluid force on the spool 12 will be very small. The area of the pressure receiving surface 12C of the spool 12 in the pilot line C is S, and the area of the ring-shaped pressure receiving surface 12d of the sleeve 12 after passing through the variable throttle unit 15 is 2 × S. Reference numeral 17 denotes a passage for the fluid to pass to the pilot line 7 after passing through the variable throttle unit 15, and reference numeral 18 denotes a drain line connected to the drain tank 4a. The pilot type throttle valve according to the present invention is configured as described above.

The pressure of the fluid L in the main circuit B is
The lower surface 12a of the spool 12 and the upper surface 12b of the spool 12 through the through hole 16 of the spool 12.
Since the area of the upper surface 2a is the same as that of the upper surface 12b, the balance of the force is achieved and the positioning of the spool 12 is not affected. Therefore, there is no problem in use in the meter-in circuit. Further, since the pilot line C is provided separately, the fluid L
Can accurately control the flow from A to B or from B to A. Further, since a pressure different from that of the main circuit is introduced into the pilot line C, even if there is a pressure fluctuation in the main circuits A and B, no vibration or the like occurs. At the same time, the pressure receiving surface 12c of the spool 12 for driving the spool 12 of the main throttle valve
And the area S and 2 × S of the pressure receiving surface 12d are the main circuits A and B
Can be arbitrarily determined irrespective of the portion in contact with the pilot line C. Therefore, it is possible to reduce the flow rate of the pilot line C and increase the responsiveness. Further, since the large through-hole 16 is formed in the center of the spool 12, the fluid force is extremely small, and it is possible to stably perform the large flow rate control, which is effective for weight reduction.

Embodiment 2 FIG. 3 is a sectional view of a cartridge type throttle valve showing another embodiment. In the throttle valve of Embodiment 1, pressure receiving surfaces 12c and 12d are shown.
Are arranged upside down. Although there is no difference in function from the first embodiment, the first and second embodiments are selectively used depending on whether the cartridge type throttle valve is always closed or opened.

Embodiment 3 In the throttle valve shown in FIG. 4, a bush 19 having a number of small holes formed in parallel is arranged at a position before the slit 14 of the pilot line C of the throttle valve shown in the first embodiment. It was done. Foreign matter in the pilot line fluid
It is a kind of filter to prevent the adverse effect on the filter. Instead of using the bush 19 having the small holes, a plurality of small holes 20 may be directly formed in the sleeve 11 in parallel as shown in FIG.

Embodiment 4 FIG. 6 shows a pilot line C of a throttle valve according to Embodiment 2 of the present invention.
This shows an example in which the bush 19 having a small hole is arranged. As shown in FIG. 7, a plurality of small holes 20 may be directly formed in the sleeve 11 instead of the bush 19 having the small holes 19a.

Embodiment 5 FIG. 8 shows a land 2 for pressure balance at the lower portion of the spool 12.
2 shows an embodiment in which the number 2 is provided. In this method, it is necessary to make the diameter of the main circuit flow control part slightly larger than the diameter of the sliding part (land diameter) below the spool 12. As a result, the pressure is affected by the main circuit pressure. In the embodiment shown in FIG. 9, the area of the drive section of the spool 12 is smaller than that shown in FIG. As compared with the example shown in FIG. 8, it is possible to increase the response and reduce the pilot flow rate.

[0013]

According to the present invention, in a cartridge type throttle valve, an external pilot system capable of introducing pressure from a line other than the main circuit line is provided, and a through hole is formed in a center portion of the spool to form a main circuit. The part that controls the flow rate is configured to balance the force, and the small holes are arranged in the pilot line, so that the following excellent effects can be obtained. (1) Even when used in a meter-out circuit, there is no need to make the tank line a large passage, and no vibration is generated even if a large flow rate flows transiently. (2) Can be used for meter-in circuits. (3) Bidirectional flow control is possible as a throttle valve. (4) Pilot flow rate can be reduced and high response can be achieved. (5) The fluid force can be reduced, and a large flow rate can be stably performed. (6) The adverse effects of foreign substances in the fluid can be avoided.

[Brief description of the drawings]

FIG. 1 is a sectional view of a cartridge type throttle valve showing one embodiment of the present invention.

FIG. 2 is a sectional view of another embodiment of the present invention.

FIG. 3 is a sectional view of another embodiment of the present invention.

FIG. 4 is a sectional view of another embodiment of the present invention.

FIG. 5 is a sectional view of another embodiment of the present invention.

FIG. 6 is a cross-sectional view of another embodiment of the present invention.

FIG. 7 is a cross-sectional view of another embodiment of the present invention.

FIG. 8 is a sectional view of another embodiment of the present invention.

FIG. 9 is a sectional view of another embodiment of the present invention.

FIG. 10 is a sectional view of a conventional cartridge type throttle valve.

FIG. 11 is a detailed view of a slit of the cartridge type throttle valve.

[Explanation of symbols]

11 ... Sleeve 12 ... Spool 12a ... Spool lower surface 12b ... Spool upper surface 12c ... Spool pressure receiving surface 12d ... Spool pressure receiving surface 13 ... Cover 14 ... Slit 15... Variable throttling part 16... Through-hole 17... Passage toward the pilot line 7 after the fluid passes through the variable throttling part 15 (passage toward the pilot valve 4) 18. ... Drain tank line connected to the drain tank 19... Bush with small holes 19a... Small holes 20... Small holes drilled in sleeve 21. Small hole 22 Land A, B Main circuit C Pilot line

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-292984 (JP, A) JP-A-63-259282 (JP, A) JP-A-63-235706 (JP, A) JP-A 64-64 6587 (JP, A) JP-A-1-238785 (JP, A) JP-A-3-209082 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F16K 31/12-31 / 42 F16K 3/24-3/26

Claims (5)

(57) [Claims] A slidable spool is provided in a sleeve in response to a pressure applied to a pressure receiving surface, and a variable throttle portion is formed between a slit formed in the spool and the sleeve so as to respond to driving of a pilot valve. Cartridge type throttle valve, comprising a pilot line through which pressure can be introduced from a line other than the main circuit line, and a through hole formed in the center of the spool. valve. 2. A slidable spool in a sleeve according to a pressure applied to a pressure-receiving surface, wherein a variable throttle portion is formed between a slit formed in the spool and the sleeve, and a variable throttle is formed in response to driving of a pilot valve. A throttle valve which operates by means of a pilot line, wherein a pilot line capable of introducing pressure from a line other than the main circuit line is provided, and a land is formed below the spool. 3. The cartridge type throttle valve according to claim 1, wherein an area of a pressure receiving surface for driving a spool of the cartridge type throttle valve can be selected to an arbitrary size. Cartridge type throttle valve. 4. The cartridge type throttle valve according to claim 1, wherein the opening degree of the main throttle valve changes in accordance with the degree of opening of the pilot valve. 5. The cartridge type throttle valve according to claim 1, wherein a plurality of small holes are formed in the fluid passage of the pilot line in parallel in the cartridge type throttle valve.