JPH0641024Y2 - Pressure control valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a pressure control valve for supplying compressed air to a single acting cylinder of an air balancer.

[Conventional technology]

Conventionally, this type of pressure control valve has a load flow path communicating with a single acting cylinder side of an air balancer (not shown), as shown in FIG.
A spool valve body 34 is slidably fitted into a valve hole 33 that opens a supply flow path 31 to which compressed air is supplied and a discharge flow path 32 that is open to the atmosphere. 34 Compressed air whose set pressure can be adjusted by a pressure adjusting valve (not shown) is introduced into the first pressure chamber 35 defined at one end, and the second pressure chamber 36 defined at the other end of the spool valve element 34 of the valve hole 33. Load channel
It introduces compressed air from 30. The spool valve element 34 moves to the left and right so that the acting forces based on the pressures of the first pressure chamber 35 and the second pressure chamber 36 are balanced, and the land portion 34A causes the load passage 30 to the discharge passage 32 and the supply passage 31. When the two acting forces are balanced, the load passage 30 is closed by the land portion 34 to obtain the same pressure in the load passage 30 as in the first pressure chamber 35.

[Problems to be solved by the invention]

However, in such a configuration, when the land portion 34A communicates the load flow passage 30 and the discharge flow passage 32 or the load flow passage 30 and the supply flow passage 31 according to the movement of the spool valve body 34, the spool valve Since the end surface where the land portion 34A and the shaft portion 34B of the body 34 are connected to each other is formed at a substantially right angle, a fluid force that opposes the axial sliding is generated in the spool valve body 34, and the fluid force acts. Since the acting force for sliding the spool valve element 34 in the axial direction must be increased by the amount, the operability of the spool valve element 34 is poor and the air balancer cannot be operated lightly.

The present invention solves such a problem and provides a pressure control valve in which the fluid force acting on the spool valve element is reduced to improve the operability of the spool valve element.

[Means for solving problems]

Therefore, the present invention is a pressure control valve that supplies compressed air that resists a load to a single-acting cylinder of an air balancer, and has a valve hole in which a spool valve element is slidably inserted in a valve body. The valve hole has a load passage communicating with the single-acting cylinder side, a supply passage for supplying compressed air to one side of the load passage with an axial gap, and a shaft for the other end of the load passage. The discharge flow path that opens to the atmosphere with a gap in the direction is opened, and the spool valve element is slidably inserted into the valve hole so that the load flow path opening point of the valve hole changes to the supply flow path opening point. The first pressure chamber for introducing compressed air from the supply flow path side is defined by a pressure control valve that allows the set pressure to be freely adjusted at one end of the spool valve body on the side, and the discharge flow from the load flow path opening portion of the valve hole. A second pressure chamber communicating with the load flow passage is defined and formed at the other end of the spool valve element on the side of the passage opening, and the spool valve And the land portion for the valve hole and sliding,
A shaft portion having a diameter smaller than that of the land portion is provided continuously on both sides of the land portion, and the action force based on the pressures of the first pressure chamber and the second pressure chamber equilibrates to open the opening of the load passage to the valve hole. The first position where the flow path is closed by the portion to block between the flow paths, and the acting force based on the pressure in the second pressure chamber is larger than the acting force based on the pressure in the first pressure chamber, so that the land portion is the load flow of the valve hole. A second position that axially slides between the passage opening portion and the supply passage opening portion to communicate between the load passage and the discharge passage and block the supply passage;
Since the acting force based on the pressure of the second pressure chamber is smaller than the acting force based on the pressure of the first pressure chamber, the land portion axially slides between the load passage opening portion and the discharge passage opening portion of the valve hole. And a third flow path that connects the load flow path and the supply flow path and blocks the discharge flow path
The land portion of the spool valve element is provided with an indentation of the environment in which it is continuously recessed from both end portions in the land portion of the spool valve element and is gradually reduced in diameter from this end surface. An on-off valve is installed that opens the load flow path against the bias of the spring by applying a pilot pressure while guiding the pilot pressure to this on-off valve from the supply flow path side. Is configured.

[Action]

In the structure of the present invention, when the spool valve element axially slides from the first position to the second position and the third position, the spool valve element is directed toward the recessed side of the continuous end faces of both shaft parts of the land part. As a result, the fluid force that opposes the sliding movement is reduced by the annular recessed portion formed so as to have a gradually decreasing diameter. Therefore, the spool valve element can be slid in the axial direction with a smaller acting force than that of the conventional valve, and the operability of the spool valve element can be improved.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

1 to 3, 1 is a valve body, which is a lower end face.
In FIG. 1A of FIG. 1, a supply flow path 3 that opens to the right and communicates with the compressed air source 2 side, a discharge flow path 4 that opens to the left of the lower end face 1A and opens to the atmosphere, and an open end to the center of the upper end face 1B. A load passage 5 communicating with a single-acting cylinder side of an air balancer described later is provided. Reference numeral 7 denotes an annular sleeve provided in the valve body 1, and has a valve hole 6 in which a plurality of opening holes 7A communicating with the respective flow paths 3, 4, 5 are opened at intervals in the axial direction. 8 is a spool valve element slidably fitted into the valve hole 6,
A large-diameter central land portion 8A that opens and closes communication with the load flow path 5 at the neutral position, and a small-diameter shaft portion from both end faces of the central land portion 8A.
Large-diameter side land portions 8C and 8D connected to 8B and 8E are formed. Reference numeral 9 denotes a ring-shaped recess formed by recessing the end face of the shaft 8B, 8E and the central land 8A, and the outer peripheral face 9A has a diameter gradually reduced from the end face toward the recess. 10 and 11 are left and right side surfaces of the valve body 1 so as to close the lateral opening of the valve hole 6.
Side plates fixed to 1C and 1D. The spool valve element 8 is slidably fitted into the valve hole 6 so that one side land portion of the spool valve element 8 on the supply channel 3 opening side from the load channel 5 opening point of the valve hole 6 The first pressure chamber 12 defined by the 8C and the side plate 10 and the other side land portion 8D and the side plate 11 of the spool valve element 8 closer to the discharge passage 4 opening than the load passage 5 opening of the valve hole 6. A second pressure chamber 13 defined by and is provided. In the first pressure chamber 12, a control flow path in which compressed air penetrates the side plate 10 from a flow path that allows the supply flow path 3 to communicate with the compressed air source 2 through a pressure control valve 14 that makes it possible to adjust the set pressure.
The compressed air from the load channel 5 is guided to the second pressure chamber 13 via the branch channel 16 provided in the valve body 1 as well as being guided to the second pressure chamber 13. Reference numerals 17 and 18 denote springs that are housed in the pressure chambers 12 and 13 and urge the spool valve body 8 to the center position. Then, the spool valve body 8 closes the opening of the load passage 5 to the valve hole 6 by the central land portion 8A due to the acting force based on the pressures of the first pressure chamber 12 and the second pressure chamber 13 that balances out. By the load flow path 5 blocking the supply flow path 3 and the discharge flow path 4, and the acting force based on the pressure of the second pressure chamber 13 is larger than the acting force based on the pressure of the first pressure chamber 12. The central land portion 8A axially slides between the opening of the load passage 5 and the opening of the supply passage 3 of the valve hole 6 so that the load passage 5 and the discharge passage 4 communicate with each other to form the supply passage 3. The second position to shut off and the acting force based on the pressure of the second pressure chamber 13 is smaller than the acting force based on the pressure of the first pressure chamber 12, so that the central land portion 8A becomes the opening of the load passage 5 of the valve hole 6. The discharge flow path 4 slides in the axial direction between the opening and the load flow path 5
And a third position where the supply flow path 4 communicates with and the discharge flow path 4 is blocked. Reference numeral 19 denotes an opening / closing valve mounted on the upper end surface 1B of the valve body 1, and an inflow passage 20 communicating with the load passage 5 of the valve body 1 below, and an outlet passage 22 communicating with the cylinder side of the air balancer described below above. Are provided respectively. Reference numeral 23 denotes an opening / closing valve body slidably inserted in a sliding hole that connects the inflow passage 20 and the outflow passage 22 in the opening / closing valve 19, and the opening / closing valve body 23 slides by the spring force of one urging spring 23B. From the flow passage that connects the supply flow passage 3 to the compressed air source 2 by being seated on the valve seat 23A formed by the continuous stepped portion of different diameter of the hole and urged so as to block between the inflow and outflow passages 20 and 22. The pilot pressure to be introduced is introduced through the other opening / closing path 23C, so that the inflow path 20 and the outflow path 2 are resisted against the bias of the spring 23B.
It is designed to communicate between the two. 21 is a single-acting type cylinder in the air balancer, and the head side chamber 21 of the cylinder 21 is
A is open to the atmosphere, and the rod side chamber 21B communicates with the outlet 22 of the on-off valve 19 to move the rod 21C up and down so as to equilibrate with the balance weight 25 connected via the chain 24.

Next, the operation of this configuration will be described.

1 to 3 show that the compressed air is not supplied from the compressed air source 2 and the pilot pressure is not supplied to the opening / closing passage 23C, the opening / closing valve 19 is the opening / closing valve by the spring force of the biasing spring 23B. The body 23 is in contact with the valve seat 23A to block between the inflow passage 20 and the outflow passage 22, and the spool valve body 8 is held at the first position by the spring force of the springs 17 and 18, and the central land portion 8A Thus, the load flow path 5 is blocked and the pressure of the rod side chamber 21B of the cylinder 21 and the acting force of the balancing weight 25 are held at a balanced position.

Next, the pressure fluid from the pressure source 2 is supplied, the on-off valve 19 communicates between the inflow passage 20 and the outflow passage 22, and the spool valve body 8 is pressurized by the weight of the balancing weight 25 to the second pressure from the load flow passage 5. The working force based on the pressure of the compressed air introduced into the chamber 13 and the working force based on the pressure of the compressed air introduced into the first pressure chamber 12 which is adjusted by the pressure adjusting valve 14 and the springs 17 and 18 act in balance. It is in the first position shown in the figure, and the flow paths 3, 4 and 5 are cut off. When the operator lifts the balancing weight 25 from this state, the pressure in the load flow path 5 decreases and the acting force based on the pressure in the second pressure chamber 13 becomes smaller than the acting force based on the pressure in the first pressure chamber 12. , The spool valve body 8 is a spring
The compressed air is supplied from the supply passage 3 to the load passage 5 by axially sliding to the third position against the 18 force. When the operator lifts the balance weight 25 at the lifted position, the acting force based on the pressure introduced from the load passage 5 into the second pressure chamber 13 is substantially equal to the acting force based on the pressure in the first pressure chamber 12. The elastic spool valve body 8 returns to the first position shown in the figure by the force of the spring 18. Further, when the operator pushes down the balancing weight 25 from the state shown in the figure, the pressure in the load flow path 5 rises and the second
The acting force based on the pressure of the pressure chamber 13 becomes larger than the acting force based on the pressure of the first pressure chamber 12, so that the spool valve body 8 causes the spring 17 to move.
The compressed air in the load passage 5 is discharged to the discharge passage 4 by axially sliding to the second position against the force. When the operator releases the balance weight 25 at the depressed position, the acting force based on the pressure introduced from the load flow path 5 into the second pressure chamber 13 is substantially equal to the acting force based on the pressure in the first pressure chamber 12. The elastic spool valve body 8 slides back to the first position shown in the figure by the force of the spring 17. Further, when the weight of the balance weight 25 is changed, compressed air having a pressure corresponding to the weight is changed to the first pressure chamber 12
The set pressure of the pressure adjusting valve 14 is adjusted so as to be introduced into the.

In this operation, the spool valve body 8 connects the load flow passage 5 and the discharge flow passage 4 from the first position where the load flow passage 5 cuts off the supply flow passage 3 and the discharge flow passage 4, and cuts off the supply flow passage 3. When sliding axially to the second position and the third position that connects the load flow path 5 and the supply flow path 3 to each other and blocks the discharge flow path 4, the end surface of the central land 8A that is continuous with the shaft parts 8B and 8E. Since the outer peripheral surface 9A is formed in a shape in which the diameter is successively reduced from the end surface toward the recessed side, the annular recessed portion 9 can reduce the fluid force that opposes sliding, so The spool valve body 8 can be slid in the axial direction with a small acting force, the operability of the spool valve body 8 is improved, and the balance weight 25 can be pushed up and down easily.

Further, in order to reduce the fluid force acting on the spool valve body, the recessed portion 9 is formed on the end surface of the central land portion 8A of the spool valve body 8.
The conventional spool valve body can be used as it is by a simple processing operation only by providing the above, and the compatibility can be improved.

Now, the angle θ of the outer peripheral surface 9A of the recess 9 corresponds to that of a conventional valve.
When I experimented with three angles of 90 °, 135 °, and 150 °,
0.40 if the fluid force coefficient that causes the fluid force is 90 °,
It was 0.18 at 135 ° and 0.16 at 150 °, and it was confirmed that the fluid force decreased as the angle θ increased. However, in the case of 150 °, the outside of the recess 9 of the central land portion 8A became thin, and the strength was reduced. Therefore, the valve of one embodiment is set to θ = 135 °.

Then, if the pressure suddenly drops significantly due to disconnection of the pipe on the upstream side of the supply flow path 3, the pressure in the first pressure chamber 7 also drops, and when the on-off valve 19 is not present, the spool valve element 8 has the discharge side. However, in this embodiment, the on-off valve 19 causes the on-off valve body 23 to be seated by the urging force of the spring 23B because the pilot pressure also greatly decreases. In this case, the balance weight 25 can be prevented from accidentally falling and safety can be secured.

[Effect of device]

As described above, according to the present invention, since the fluid force on the spool valve element is reduced, the spool valve element can be slid in the axial direction with a smaller acting force than the conventional valve, and the operability of the spool valve element is reduced. Is improved, and the air balancer can be operated lightly.

In addition, this improvement in operability can be realized by a simple machining operation that simply provides a recess on the end face of the land portion of the spool valve body,
The compatibility with the conventional one can be improved.

Furthermore, even if the pressure drops suddenly upstream of the supply flow path due to pipe disconnection, etc., the single-acting cylinder of the air balancer can be prevented from dropping due to the load by closing the on-off valve, which improves safety. Can be secured.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a pressure control valve showing an embodiment of the present invention, FIG. 2 is an enlarged sectional view of a recess formed in a land portion of a spool valve body, and FIG. 3 is a pressure control of the present invention. FIG. 4 is a circuit diagram of a fluid actuator device using a valve, and FIG. 4 is a vertical sectional view of a conventional pressure control valve. DESCRIPTION OF SYMBOLS 1 ... Valve main body, 3 ... Supply flow path, 4 ... Exhaust flow path, 5 ... Load flow path, 6 ... Valve hole, 8 ... Spool valve body, 8A ... Land part, 8B,
8E ... Shaft part, 9 ... Recessed part, 9A ... Outer peripheral surface, 12 ... First pressure chamber,
13 ... Second pressure chamber, 14 ... Pressure adjusting valve, 19 ... Open / close valve, 21 ... Single acting cylinder.

Claims (1)

[Scope of utility model registration request] 1. A pressure control valve for supplying compressed air against a load to a single-acting cylinder of an air balancer, wherein a valve hole for slidably inserting a spool valve body is provided in a valve body, and the valve hole is provided. Includes a load flow path communicating with the single-acting cylinder side, a supply flow path to which compressed air is supplied to one side of the load flow path with an axial gap, and an axial direction to the other end of the load flow path. A discharge flow path that opens to the atmosphere with a gap is provided by opening, and a spool valve element is slidably fitted into the valve hole to allow the load flow path opening portion of the valve hole to be closer to the supply flow path opening portion. A first pressure chamber that introduces compressed air from the supply flow path side is defined by a pressure control valve that allows the set pressure to be adjusted at one end of the spool valve body, and a discharge flow path opening from the load flow path opening portion of the valve hole. A second pressure chamber communicating with the load flow path is defined at the other end of the spool valve body at the location side, and the spool valve body has a valve hole. A land portion that slides and a shaft portion that is continuously provided on both sides of the land portion and has a diameter smaller than that of the land portion are provided, and the action force based on the pressures of the first pressure chamber and the second pressure chamber equilibrate to each other so that the load passage The first position where the opening to the valve hole is blocked by the land portion to block the flow paths from each other and the acting force based on the pressure in the second pressure chamber is larger than the acting force based on the pressure in the first pressure chamber. A second position in which the portion axially slides between the load flow passage opening portion and the supply flow passage opening portion of the valve hole to connect the load flow passage and the discharge flow passage to cut off the supply flow passage; Since the acting force based on the pressure in the pressure chamber is smaller than the acting force based on the pressure in the first pressure chamber, the land portion slides in the axial direction between the load passage opening portion and the discharge passage opening portion of the valve hole. A third position for connecting the load flow path and the supply flow path and blocking the discharge flow path,
The land portion of the spool valve body is provided with a recessed part on the end face connected to both shaft parts of the environment that is gradually recessed in a reduced diameter from this end face, and the valve body is equipped with a spring to block the load flow path. A pressure control valve that is energized and installs an on-off valve that opens the load flow path against the bias of the spring by applying pilot pressure and guides pilot pressure to this on-off valve from the supply flow path side.