TWI564485B - Control valve - Google Patents

Description

Control valve

The present invention relates to a control valve for use in a hydraulic circuit of an industrial vehicle or the like.

An example of the control valve that is widely used in an industrial vehicle represented by a stacker is as follows.

This control valve constitutes a hydraulic circuit that supplies an operating hydraulic pressure to the cylinder head 2a side of the hydraulic actuator 2, and the hydraulic actuator 2 drives the elevator L as a driving target. As shown in FIGS. 4 and 5 , the control valve includes a housing 1 , a spool valve body 3 that can move forward and backward inside the sleeve 1 e provided in the housing 1 , and a built-in housing 1 . Lift the lock poppet valve 4.

The casing 1 includes a high pressure passage 1a that communicates with a pump P as an actuating hydraulic pressure supply source, a low pressure passage 1b that communicates with a storage tank T for storing an operating fluid, and a cylinder head 2a that communicates with the hydraulic actuator 2. The cylinder passage 1c and a sleeve 1e that is connected to the high pressure passage 1a, the low pressure passage 1b, and the cylinder passage 1c and that is slidable inside the spool body 3 is provided. The working fluid discharge passage 1d is branched from the cylinder passage 1c, and when the spool body 3 is at a lowering position D to be described later, the operating fluid discharge passage 1d communicates with the low pressure passage 1b.

The spool body 3 constitutes a switching valve that selectively selects a neutral position C, a lowered position D as shown in FIG. 4, and a raised position U as shown in FIG. 5, the neutral position C making the high pressure The passage 1a and the low-pressure passage 1b are separated from the cylinder passage 1c, and the lowered position D communicates between the low-pressure passage 1b and the cylinder passage 1c, and the elevated position U causes the high-pressure passage 1a to The cylinder passages 1c communicate with each other.

The lift lock poppet valve 4 may select an open state in which the hydraulic actuator 2 communicates with the sleeve 1e, and a partition state in which the hydraulic actuator 2 and the sleeve 1e are spaced apart from each other. . Further, the lift lock poppet valve 4 uses a poppet valve body 4a having a back pressure chamber 4a1 therein and a direction in which the poppet valve body 4a is seated on the valve seat (the lift lock poppet valve 4 is closed) Force spring 4b. The opening and closing valve of the lift lock poppet valve 4 is performed by a differential pressure between the inside and the outside of the back pressure chamber 4a1.

Further, inside the casing 1, a back pressure passage 1g is provided which communicates the back pressure chamber 4a1 with the operating fluid discharge passage 1d and is provided with a solenoid valve 5 in the middle.

Further, the control valve further includes an emergency operation valve 6 that utilizes an emergency operation valve body 62 that is retractably provided to the use position R and the departure position of the push valve body 4a. The retracted position S of the poppet valve body 4a is described. The emergency operating valve 6 includes an emergency valve plug 61 attached to the housing 1 and a part of the emergency operating valve body 62 disposed in the emergency valve plug 61. More specifically, the emergency valve plug 61 is provided with a female screw portion 611, and the emergency operating valve body 62 is provided with an external thread 621 that can be screwed into the female screw portion 611. Further, the emergency operation valve body 62 is screwed forward and backward with respect to the emergency valve plug 61 and the housing 1 by manual operation.

If the operator moves the spool body 3 of the control valve to the lowered position D by lever operation or the like while sitting in the driver's seat, the solenoid valve 5 normally opens the valve to cause the actuating fluid to lift from the lifter The back pressure chamber 4a1 of the valve body 4a is discharged to the storage tank T through the cylinder passage 1c, the operating fluid discharge passage 1d, and the low pressure passage 1b, thereby causing a difference between the inner side and the outer side of the back pressure chamber 4a. Pressure. At this time, the lift lock poppet valve 4 is opened by the force derived from the differential pressure, and the actuating liquid introduced from the hydraulic actuator 2 to the cylinder passage 1c is directly introduced into the actuating liquid discharge passage. 1d, and discharged to the storage tank T through the low pressure passage 1b.

On the other hand, when the solenoid valve 5 is closed due to the malfunction of the solenoid valve 5, as shown in FIG. 4, the emergency operation valve body 6 is moved from the retracted position S to the use position R by the manual operation. The valve body 4a is opened to open the lift lock poppet valve 4 (for example, refer to Patent Document 1).

However, in the cylinder passage 1c, a portion near the emergency operation valve 6 is provided, and a high-pressure operating fluid from the pump P and a relatively low-pressure operating fluid returning from the hydraulic actuator 2 to the storage tank T are distributed. Acting fluid. Therefore, as shown in FIG. 5, when the spool body 3 reaches the raised position U, a part of the high-pressure operating fluid supplied from the pump P reaches the gap 6s between the emergency operating valve body 62 and the emergency valve plug 61.

In the conventional configuration, as shown in FIGS. 4 to 6, an O-ring 623 is provided between the emergency operation valve body 62 and the emergency valve plug 61 to prevent liquid leakage from the gap 6s. However, when the spool body 3 reaches the raised position U, the high-pressure operating fluid reaches the gap 6s, and the O-ring 623 is sometimes exposed from the gap and damaged. Further, if the O-ring 623 is damaged, there is a problem that liquid leakage is likely to occur.

In order to suppress the occurrence of the undesirable condition, it is considered to reduce the gap between the emergency operation valve body and the emergency valve plug, or to provide a separate support ring. However, when the former is employed, a gap is formed between the emergency operating valve body and the emergency valve plug to prevent the O-ring from being exposed and the emergency valve body can be slid, which causes other problems requiring high machining accuracy. Further, when the latter is employed, since not only the O-ring but also the support ring is provided, there arises a new problem such as an increase in the number of parts and an increase in manufacturing effort accompanying this.

The above problem is also caused by the configuration of the working fluid discharge passage that directly connects the back pressure chamber and the short tube. The reason is that when such a configuration is adopted, if the spool body is placed in the neutral position for a long time, the actuating hydraulic pressure of the portion of the actuator and the hydraulic pressure of the actuating liquid discharge passage can be long by the poppet valve body of the cylinder passage. The time remains equal, especially when the load on the elevator is large, the operating hydraulic pressure becomes relatively high.

PRIOR ART DOCUMENT Patent Literature Patent Document 1: Japanese Patent Laid-Open Publication No. 2013-57363

[Problems to be solved by the invention]

The intended purpose of the present invention is to suppress leakage without requiring high machining accuracy and without requiring special parts.

[Means for solving the problem]

In order to solve the above problems, the control valve of the present invention has the configuration described below. That is, the control valve of the present invention includes a casing including a high pressure passage communicating with the actuating hydraulic pressure supply source, a low pressure passage communicating with the storage tank for storing the actuating liquid, a cylinder passage communicating with the hydraulic actuator, and a connection to a sleeve of the high pressure passage, the low pressure passage and the cylinder passage; a lift lock poppet valve having a poppet valve body, wherein the poppet valve body is disposed in the cylinder passage, and the sleeve and the hydraulic pressure are selected An open position in which the actuator communicates and a partitioning position that separates the sleeve from the hydraulic actuator, and has a back pressure chamber therein; a back pressure passage that allows the back pressure chamber of the poppet valve body to The low-pressure passage is connected, and a solenoid valve is provided in the middle; and the emergency operation valve has an emergency operation valve body, and the emergency operation valve body is retractably provided at a position for pressing the poppet valve body and leaving the poppet valve Between the retracted positions of the body, and when the retracted position is selected, the seat is seated on the valve seat and a mechanical seal is performed.

According to this configuration, when the emergency operation valve body is disposed at the retracted position, the emergency operation valve body is seated on the valve seat and mechanically sealed, so that even when the high-pressure operating fluid is introduced into the emergency operation valve body In the vicinity, it is also possible to suppress the gap between the emergency operation valve body and the emergency valve plug for the emergency operation valve body to advance and retreat. Therefore, it is also possible to suppress the occurrence of a malfunction caused by the high-pressure operation liquid entering the gap between the emergency operation valve body and the emergency valve plug. In particular, if an O-ring is disposed in the gap, the O-ring can more effectively suppress introduction into the gap when the emergency operation valve body advances and retracts between the retracted position and the use position. The leakage of the working fluid.

[Effects of the Invention]

According to the present invention, it is possible to suppress leakage without requiring high machining accuracy and without using special parts.

Hereinafter, an embodiment of the present invention will be described with reference to Figs. 1 to 3 . In the following description, the same reference numerals and symbols are attached to the portions corresponding to the respective portions of the conventional control valve described with reference to FIGS. 4 to 6 .

As shown in FIG. 1 and FIG. 2, the control valve of the present embodiment is mounted on a stacker, and constitutes a hydraulic circuit that supplies hydraulic pressure to the hydraulic actuator 2, and the hydraulic actuator 2 drives the lift L as a drive target. . Specifically, the control valve includes a housing 1, a short tube valve body 3 slidable in a sleeve 1e provided in the housing 1, and a lift in a cylinder passage 1c provided inside the housing 1. Locking the poppet valve 4 and the emergency operating valve 6 including the emergency operating valve body 62, the emergency operating valve body 62 is retractably provided at a use position R of the poppet valve body 4a that presses the lift lock poppet valve 4 and It is separated from the retracted position S of the poppet valve body 4a of the lift lock poppet valve 4.

The housing 1 has the same construction as the known housing that can be used in such a control valve. More specifically, it includes a high pressure passage 1a that communicates with the pump P as the operating hydraulic pressure supply source, a low pressure passage 1b that communicates with the storage tank T for storing the operating fluid, and a hydraulic pressure that communicates with the elevator L that is the driving target. The cylinder passage 1c of the cylinder head 2a of the actuator 2 and the sleeve 1e connected to the high pressure passage 1a, the low pressure passage 1b, and the cylinder passage 1c. An operating fluid discharge passage 1d that communicates with the low pressure passage 1b when the spool body 3 is selected at a lowering position D to be described later is provided branched from the cylinder passage 1c.

The spool body 3 has the same configuration as the short tube body known in the control valve. That is, the spool body 3 constitutes a switching valve that selectively selects a neutral position C, a lowered position D as shown in FIG. 1, and a raised position U as shown in FIG. 2, the neutral position C The high pressure passage 1a and the low pressure passage 1b are separated from the cylinder passage 1c, and the lowering position D causes the low pressure passage 1b and the cylinder passage 1c to communicate with each other through the operating fluid discharge passage 1d. The raised position U communicates between the high pressure passage 1a and the cylinder passage 1c.

The lift lock poppet valve 4 also has the same construction as the lift lock poppet valve that is well known for use in such control valves. That is, the lift lock poppet valve 4 can be in an open state in which the sleeve 1e communicates with the cylinder head 2a and a partitioned state in which the sleeve 1e is spaced apart from the cylinder head 2a. Further, the lift lock poppet valve 4 is a spring 4b that biases the valve body 4a and biases the lift valve body 4a in a direction in which the lift lock poppet valve 4 is closed. Inside the poppet valve body 4a, there is a back pressure chamber 4a1. Inside the casing 1, a back pressure passage 1g is provided which communicates the back pressure chamber 4a1 with the cylinder passage 1b and is provided with a solenoid valve 5 in the middle. The back pressure chamber 4a1 communicates with the cylinder passage 1c via the back pressure passage 1g. Further, when the spool body 3 selects the lowering position D, the back pressure chamber 4a1 communicates with the tank T through the actuating liquid discharge passage 1d and the low pressure passage 1b.

The solenoid valve 5 also has the same configuration as the known solenoid valve that can be used for such a control valve. That is, when the spool body 3 is in the lowered position D and the solenoid valve opening condition of the operator is not taken off, the solenoid valve 5 is opened.

With regard to the emergency operation valve 6, when the solenoid valve 5 is not opened despite satisfying the solenoid valve opening condition, the lift lock poppet valve 4 is opened by manual operation. Specifically, as shown in FIGS. 1 to 3, the emergency valve plug 61 disposed at a position facing the cylinder passage 1c of the casing 1 and the emergency operation valve body 62 that can advance and retreat within the emergency valve plug 61 are included. .

As shown in FIG. 3, the emergency valve plug 61 has a female screw portion 611 inside and a valve body insertion hole 612 located at a portion closer to the lock lift valve 4 side than the female screw portion 611.

As shown in FIG. 3, the emergency operation valve body 62 includes an external thread portion 621 that can be screwed into the internal thread portion 611 of the emergency valve plug 61, and a main body 622 that is disposed above the external thread portion 621. Locking the position on the side of the poppet valve 4 and sliding in the valve body insertion hole 612; an O-ring 623 disposed between the main body 622 and the valve body insertion hole 612; and a pressing portion 624 from the main body 622 protrudes from the lift lock poppet valve 4, and presses the poppet valve body 4a when the use position R is selected; and the seal portion 625 is disposed between the press portion 624 and the main body 622, and when the retracted position S is selected The seat 613 of the emergency valve plug 61 is seated and mechanically sealed.

Here, when the operator moves the spool body 3 from the neutral position C to the lowered position D by lever operation or the like while sitting in the driver's seat, the solenoid valve 5 is normally opened to lift the valve body. The operating fluid in the back pressure chamber 4a1 of 4a is introduced into the storage tank T through the actuating liquid discharge passage 1d and the low pressure passage 1b, so that a differential pressure is generated between the inside of the back pressure chamber 4a1 and the outside thereof, and the differential pressure is utilized. The force causes the poppet valve body 4a to leave the valve seat, and the operating fluid from the hydraulic actuator 2 is introduced into the tank T.

On the other hand, when the spool body 3 is moved from the neutral position C to the lowered position D, in the case where the solenoid valve 5 is not opened due to a failure or the like, as shown in Fig. 1, the emergency operation valve body 62 is provided. The screw feed is manually operated to approach the poppet valve body 4a, and then moved to the use position R and the poppet valve body 4a is pressed, whereby the lift lock poppet valve 4 is opened. After the operation of lowering the elevator L is completed, when the spool body 3 is returned from the descending position D to the neutral position C, the emergency operating valve body 62 is manually operated and screwed to move to the retracted position S. The seal portion 625 is seated on the valve seat 613 while leaving the poppet valve body 4a. Here, when the emergency operation valve body 62 advances and retracts between the retracted position S and the use position R, the O-ring 623 can be suppressed from being introduced into the emergency operation valve body 62 and the emergency valve plug 61. The operating fluid between the gaps of 6s leaked out.

Further, when the operator moves the spool body 3 from the neutral position C to the raised position U by lever operation or the like while sitting in the driver's seat, as shown in FIG. 2, the operating fluid passes through the cylinder from the high pressure passage 1a. The passage 1c is introduced to the hydraulic actuator 2. At this time, the pressing portion 624 of the emergency operation valve body 62 receives the hydraulic pressure of the operating fluid from the high pressure passage 1a. However, since the seal portion 625 of the emergency operation valve body 62 is seated on the valve seat 613 and mechanically sealed, the operating fluid introduced into the gap 6s between the emergency operation valve body 62 and the emergency valve plug 61 is In a small amount, the hydraulic pressure is also smaller than the hydraulic pressure from the pump P.

That is, according to the present embodiment, when the emergency operation valve body 62 is at the retracted position S, the sealing portion 625 is seated on the valve seat 613 and mechanically sealed, whereby the following effects can be obtained. Specifically, since the hydraulic pressure of the operating fluid introduced into the gap 6s between the emergency operation valve body 62 and the emergency valve plug 61 is smaller than the hydraulic pressure from the pump P, it is possible to suppress the emergency liquid from entering the emergency due to the high pressure. The O-ring 623 is exposed between the valve body 62 and the casing 1 to be exposed from the gap, thereby causing a problem of liquid leakage. Further, since the hydraulic pressure of the operating fluid introduced into the gap 6s is small, the O-ring 623 can be more effectively suppressed from moving forward and backward between the retracted position S and the use position R by the O-ring 623. The leakage of the actuation liquid introduced into the gap 6s is isochronous.

In addition, this embodiment is not limited to the said embodiment.

For example, in the above-described embodiment, a configuration is adopted in which a back pressure passage is branched from the cylinder passage and a working fluid discharge passage is branched from the cylinder passage. However, the present invention is also applicable to a control valve having the following configuration. . That is, the present invention can also be applied to a control valve having an actuating liquid discharge passage directly connecting the back pressure chamber and the short pipe and having a solenoid valve and an emergency operating valve in the middle of the actuating liquid discharge passage. For the valve body of the emergency operation valve.

Further, in the above-described embodiment, the emergency valve plug is attached to the casing, and the emergency operation valve body can be advanced and retracted inside the emergency valve plug, but the present invention can also be applied to the casing directly. A control valve for the hole in which the valve body is inserted in an emergency operation.

Further, various modifications may be made without departing from the spirit and scope of the invention.

[Industrial availability]

According to the present invention, it is possible to provide a control valve which can be configured to suppress leakage without requiring high machining accuracy and without using special parts.

1‧‧‧shell
1a‧‧‧High-pressure access
1b‧‧‧Low-pressure path
1c‧‧‧Cylinder access
1d‧‧‧actuating fluid discharge path
1e‧‧‧ sleeve
1g‧‧‧back pressure path
2‧‧‧Hydraulic actuator
2a‧‧‧Cylinder head
3‧‧‧Short pipe body
4‧‧‧ Lifting lock poppet valve
4a‧‧‧Floating the valve body
4a1‧‧‧ Back pressure chamber
4b‧‧‧ Spring
5‧‧‧ solenoid valve
6‧‧‧Emergency operating valve
6s‧‧‧ gap
61‧‧‧ plug
62‧‧‧Emergency operation of the valve body
611‧‧‧Threaded Department
612‧‧‧ valve body insertion hole
613‧‧‧ valve seat
621‧‧‧External thread
622‧‧‧ Subject
623‧‧‧O-ring
624‧‧‧ Pressing Department
625‧‧‧ Sealing Department
D‧‧‧Down position
L‧‧‧ Lift
P‧‧‧Working hydraulic supply (pump)
R‧‧‧Location
S‧‧‧Retracted position
T‧‧‧ storage tank
U‧‧‧ rising position

Fig. 1 is a schematic view showing a control valve according to an embodiment of the present invention. Fig. 2 is an explanatory view of the operation of the control valve of the embodiment. Fig. 3 is a schematic view showing the emergency operation valve of the embodiment. 4 is a schematic view showing a conventional control valve. Fig. 5 is an explanatory view of the operation of the conventional control valve. Fig. 6 is a schematic view showing a conventional emergency operation valve.

1‧‧‧shell

1a‧‧‧High-pressure access

1b‧‧‧Low-pressure path

1c‧‧‧Cylinder access

1d‧‧‧actuating fluid discharge path

1e‧‧‧ sleeve

1g‧‧‧back pressure path

2‧‧‧Hydraulic actuator

2a‧‧‧Cylinder head

3‧‧‧Short pipe body

4‧‧‧ Lifting lock poppet valve

4a‧‧‧Floating the valve body

4a1‧‧‧ Back pressure chamber

4b‧‧‧ Spring

5‧‧‧ solenoid valve

6‧‧‧Emergency operating valve

61‧‧‧ plug

62‧‧‧Emergency operation of the valve body

621‧‧‧External thread

622‧‧‧ Subject

623‧‧‧O-ring

624‧‧‧ Pressing Department

625‧‧‧ Sealing Department

D‧‧‧Down position

L‧‧‧ Lift

P‧‧‧Working hydraulic supply (pump)

R‧‧‧Location

T‧‧‧ storage tank

Claims (1)

A control valve includes a housing including a high pressure passage connected to an actuating hydraulic supply source, a low pressure passage communicating with a storage tank for storing actuating liquid, a cylinder passage communicating with the hydraulic actuator, and a high pressure connection a passage, the low pressure passage and a sleeve of the cylinder passage; a lift lock poppet valve having a poppet valve body, wherein the poppet valve body is disposed in the cylinder passage, and the sleeve and the sleeve are selected An open position in which the hydraulic actuator communicates and a partition position that separates the sleeve from the hydraulic actuator, and has a back pressure chamber therein; a back pressure passage that causes back pressure of the poppet body The chamber is connected to the low-pressure passage, and is provided with a solenoid valve in the middle; and an emergency operation valve includes an emergency operation valve body, and the emergency operation valve body is retractably provided at a position where the push valve body is pressed and a position to leave the chamber The mechanical shaft seal is realized between the retracted positions of the poppet valve body and when the retracted position is selected, by sealing the sealing body of the emergency operating valve body to the valve seat.