JP2018017334A - Flow control valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spool type flow control valve capable of suppressing pressure of hydraulic oil from rising, even in a case where a flow rate of hydraulic oil is different between a supply side and return side.SOLUTION: A flow control valve 100 includes: a body 1 having a supply port P, a discharge port T and a port B and a port A configured to alternatively inflowing/outflowing hydraulic oil; and a spool 2. The spool 2 is configured to move in an X2 direction to form a first opening 41 communicating between the port B and the supply port P, and form a second opening 42 communicating between the port A and the discharge port T. The flow control valve 100 is configured such that an opening area A11 of the first opening 41 is made smaller than an opening area A12 of the second opening 42.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a flow rate control valve, and more particularly to a flow rate control valve that controls a flow rate by opening and closing a port by moving a spool in a body.

  Conventionally, a flow rate control valve that controls a flow rate by opening and closing a port by moving a spool in a body is known (see, for example, Patent Document 1).

  Patent Document 1 discloses a flow control valve including a body provided with a port through which hydraulic oil enters and exits, and a spool that moves within the body and opens and closes the port. The body is provided with a supply port through which hydraulic oil is supplied, a discharge port through which hydraulic oil is discharged, and a first port and a second port through which hydraulic oil flows in or out alternately. When the spool is moved to the first port side, the first port and the supply port communicate with each other, and the second port and the discharge port communicate with each other. When the spool is moved to the second port side, the second port and the supply port communicate with each other, and the first port and the discharge port communicate with each other. The flow control valve is used for controlling a hydraulic cylinder, for example.

JP 2010-127373 A

  Here, when a flow control valve is connected to a single rod cylinder, etc., the pressure receiving area (or volume change) differs between the rod-side oil chamber and the head-side oil chamber by the amount of the rod. The amount of return oil from the head side oil chamber is larger than the amount of hydraulic oil supplied to the side oil chamber.

  In that case, for example, when the first port and the second port are respectively connected to the rod-side oil chamber and the head-side oil chamber of the hydraulic cylinder, and the working oil is supplied from the supply port to the rod-side oil chamber via the first port, Since the amount of return oil returning from the head-side oil chamber to the discharge port via the second port is relatively large, there is a disadvantage in that the hydraulic pressure increases between the return-side second port and the discharge port. . Unnecessary increases in hydraulic pressure cause heat generation, noise, and energy loss, so it is desirable to suppress the increase in hydraulic oil pressure even when the hydraulic oil flow rate differs between the supply side and the return side. It is rare.

  The present invention has been made to solve the above-described problems, and the object of the present invention is to increase the pressure of the hydraulic oil even when the flow rate of the hydraulic oil is different between the supply side and the return side. It is an object of the present invention to provide a spool-type flow rate control valve capable of suppressing the above-described problem.

  In order to achieve the above object, a flow control valve according to the present invention includes a supply port to which hydraulic oil is supplied, a discharge port from which hydraulic oil is discharged, and a first that allows the hydraulic oil to flow in or out alternately. A body including a port and a second port, and a spool held in the body and moved by an operating force supplied from the outside, and the spool moves in the first direction to move the first port and the supply. A first opening for communicating the port is formed, and a second opening for communicating the second port and the discharge port is formed. The opening area of the first opening is smaller than the opening area of the second opening. It is configured as follows.

  In the flow rate control valve according to the present invention, as described above, by moving in the first direction, the first opening for communicating the first port and the supply port is formed, and the second port for communicating the second port and the discharge port. A spool for forming the opening is provided, and the flow control valve is configured so that the opening area of the first opening is smaller than the opening area of the second opening. As a result, the opening area of the first opening through which hydraulic oil flowing out from the supply port through the first port passes can be made relatively small, and the return oil that returns to the discharge port through the second port passes. The opening area of the second opening can be made relatively large. Therefore, if the oil chamber on the side where the pressure receiving area (or volume change amount) is small is connected to the first port and the oil chamber on the side where the pressure receiving area is large is connected to the second port, the flow rate of the hydraulic oil supplied Even if the flow rate of the return oil increases, the opening area of the second opening through which the return oil passes can be relatively increased, so that the flow rate of the hydraulic oil differs between the supply side and the return side. However, it can suppress that the pressure of hydraulic fluid rises.

  In the flow control valve according to the invention, preferably, the spool includes a flow rate adjusting unit that forms an opening with the body as the spool moves and changes an opening area according to the amount of movement of the spool. The adjustment unit includes a first flow rate adjustment unit that forms the first opening with an opening area smaller than the opening area of the second opening. If comprised in this way, the opening area of a 1st opening can be easily made into the opening area of a 2nd opening only by changing the shape of the 1st flow volume adjustment part of the spool for adjusting a flow volume according to a movement amount. On the other hand, it can be made relatively small.

  In the flow control valve according to the invention, preferably, the first port and the second port are connected to a first oil chamber and a second oil chamber, respectively, having different pressure receiving areas in the hydraulic cylinder, and the first oil chamber and the second oil chamber are respectively connected. Based on the pressure receiving area of each chamber, the opening areas of the first opening and the second opening are set. If comprised in this way, it will become possible to determine the difference of each opening area of a 1st opening and a 2nd opening according to the magnitude | size of the difference of the pressure receiving area of a 1st oil chamber and a 2nd oil chamber. . That is, since the flow rate on the return side (second opening side) relative to the flow rate on the supply side (first opening side) can be known, the opening areas of the first opening and the second opening are set so as to have an opening area corresponding to the flow rate difference. By doing, it can suppress more effectively that the pressure of hydraulic fluid rises.

  In the flow control valve according to the present invention, preferably, the spool moves in the second direction to form a third opening for communicating the second port and the supply port, and for communicating the first port and the discharge port. The opening area of the first opening per unit movement amount of the spool in the first direction is smaller than the opening area of the third opening per unit movement amount of the spool in the second direction. It is comprised so that it may become. If comprised in this way, the flow volume of the hydraulic fluid which flows out out of a supply port via a 2nd port can be enlarged compared with the case where it flows out of a supply port via a 1st port. Therefore, when connecting the oil chamber with the smaller pressure receiving area of the hydraulic cylinder to the first port and connecting the oil chamber with the larger pressure receiving area to the second port, the discharge flow rate of hydraulic oil to each oil chamber Since it can be made different according to the difference in pressure receiving area, the difference in rod moving speed at the same spool movement amount (same valve opening) is reduced during rod extension control and rod retract control. Can do.

  In this case, preferably, the spool includes a flow rate adjusting unit that forms an opening with the body in accordance with the movement of the spool and changes the opening area according to the amount of movement of the spool. A first flow rate adjustment unit that forms one opening, and a second flow rate adjustment unit that has a shape or dimension different from that of the first flow rate adjustment unit and forms a third opening. If comprised in this way, the opening area of a 1st opening will be easily made with respect to the opening area of a 3rd opening only by changing the shape or dimension of the 1st flow volume adjustment part and 2nd flow volume adjustment part of a spool. It can be made relatively small.

  In the configuration in which the first flow rate adjustment unit and the second flow rate adjustment unit are provided in the spool, preferably, the flow rate adjustment unit is a notch provided in the outer peripheral surface of the spool, and the first flow rate adjustment unit and the second flow rate adjustment unit. Is formed so that the planar shape or depth of the notches are different from each other. If comprised in this way, the structure which makes an opening area different can be easily implement | achieved by varying the planar shape or depth of a notch with a 1st flow volume adjustment part and a 2nd flow volume adjustment part.

  In the configuration in which the first flow rate adjustment unit and the second flow rate adjustment unit are provided in the spool, preferably, the flow rate adjustment unit is a tapered portion formed so as to reduce the outer diameter of the outer peripheral surface of the spool. The adjustment part and the second flow rate adjustment part are formed so that the inclination angles of the taper part are different from each other. If comprised in this way, the structure which varies an opening area can be implement | achieved easily by varying the inclination-angle of a taper part with a 1st flow volume adjustment part and a 2nd flow volume adjustment part.

  In a configuration in which the opening area of the first opening per unit movement amount is smaller than the opening area of the third opening per unit movement amount, the body is preferably arranged on the first direction side of the spool, and the first direction A first urging portion that is compressed as the spool moves to the second direction, and a second urging portion that is disposed on the second direction side of the spool and is compressed as the spool moves in the second direction. In addition, the spring constant of the first biasing part is smaller than the spring constant of the second biasing part. With this configuration, the spool can be easily moved in the first direction. Therefore, the flow rate is secured by increasing the opening degree of the first port (opening area of the first opening) by the amount corresponding to the small opening area of the first opening per unit movement amount when moving the spool in the first direction. Will be able to. As a result, the flow rate from the first port or the second port when the same operating force is supplied to the spool in the first direction and the second direction can be made closer, so the flow rate itself when each port is opened is When control is desired, the flow rate can be easily adjusted.

  In the configuration in which the opening area of the first opening per unit movement amount is smaller than the opening area of the third opening per unit movement amount, the controller preferably controls the operating force supplied to the spool in the second direction. The gradient of the supply operating force with respect to the flow rate command value in the first direction is larger than the gradient of the supply operating force with respect to the flow rate command value. If comprised in this way, when opening and closing a 1st port or a 2nd port by the same flow command value, it will become possible to enlarge the opening degree (opening area of a 1st opening) of a 1st port. As a result, the flow rate from the first port or the second port when opening and closing with the same flow rate command value can be made closer, so that it is easy to align the flow rate when it is desired to control the flow rate itself when each port is opened. be able to.

  According to the present invention, as described above, there is provided a spool-type flow rate control valve capable of suppressing an increase in the pressure of hydraulic oil even when the flow rate of hydraulic oil is different between the supply side and the return side. can do.

It is the figure which showed an example of the hydraulic circuit to which a flow control valve is applied. It is sectional drawing which showed the flow control valve by 1st Embodiment. It is the perspective view which showed the structural example of the spool. It is a figure for demonstrating the opening and opening area in a PB control state. It is a figure for demonstrating the opening and opening area in a PA control state. It is the figure which showed the state which the spool moved to the standby position. It is the figure which showed the state (PB control state) which the spool moved to the control area. It is the perspective view which showed the spool by a comparative example. It is the figure which showed the relationship between the moving amount | distance of the spool and opening area in a comparative example, and the relationship between discharge flow volume and pressure loss. It is the figure which showed the relationship between the moving amount | distance of the spool in 1st Embodiment, and opening area, and the relationship between discharge flow volume and pressure loss. It is the figure which showed the relationship between the movement amount of the spool and cylinder speed in a comparative example and 1st Embodiment. It is the perspective view which showed the 1st modification of the spool by 1st Embodiment. It is a figure for demonstrating the flow volume adjustment part of the spool by a 1st modification. It is the perspective view which showed the 2nd modification of the spool by 1st Embodiment. It is a figure for demonstrating the flow volume adjustment part of the spool by a 1st modification. It is sectional drawing which showed the flow control valve by 2nd Embodiment. It is the figure which showed the relationship between the flow instruction | command in 2nd Embodiment, the movement amount of a spool, and opening area. It is the figure which showed the relationship between the flow instruction | command in 3rd Embodiment, supply operating force, and opening area. It is sectional drawing which showed the modification of the flow control valve by 1st Embodiment. It is sectional drawing which showed the PB control state of the flow control valve of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[First Embodiment]
First, the flow control valve 100 according to the first embodiment will be described with reference to FIGS.

  The flow control valve 100 according to the first embodiment is a hydraulic valve that controls the supply of hydraulic oil to a hydraulic machine such as a hydraulic actuator. The flow control valve 100 of the first embodiment is configured as a proportional flow control valve of a spool type (slide spool type). The proportional flow rate control valve is a control valve configured so that the flow rate of the output hydraulic oil is proportional to the position (movement amount) of the spool.

(Whole structure of hydraulic circuit)
The flow control valve 100 according to the first embodiment is a lifting hydraulic cylinder (lift cylinder) or the like, and is preferably used for hydraulic fluid flow control for hydraulic machines having different pressure receiving areas in each oil chamber. In the following, an example will be described in which the flow control valve 100 is connected to a lifting hydraulic cylinder (lift cylinder) of a forklift and the flow control valve 100 is used for supply control of hydraulic oil for raising and lowering the cylinder.

  As shown in FIG. 1, the flow control valve 100 is connected to a hydraulic cylinder 101, a hydraulic pump 102, and an oil tank 103, respectively. Specifically, the flow control valve 100 includes four oil passages: port A, port B, supply port P, and discharge port T. Port A and port B are examples of “second port” and “first port” in the claims, respectively.

  The hydraulic cylinder 101 has a structure in which a piston 111 and a rod 112 connected to the piston 111 are slidably provided in a tube 113. The hydraulic cylinder 101 is, for example, a single rod cylinder, and the rod 112 protrudes from one end side of the tube 113 to the outside. The inside of the tube 113 is partitioned by a piston 111 into a first oil chamber 114 on the rod side and a second oil chamber 115 on the head side. The first oil chamber 114 has a pressure receiving area A1, and the second oil chamber 115 has a pressure receiving area A2. The pressure receiving area A1 of the first oil chamber 114 is smaller than the pressure receiving area A2 of the second oil chamber 115 by the area of the rod 112 occupying the oil chamber (A1 <A2).

  Port B and port A of the flow control valve 100 are connected to a first oil chamber 114 and a second oil chamber 115, which have different pressure receiving areas in the hydraulic cylinder 101, respectively. That is, port A is connected to the second oil chamber 115 via the check valve 104. Port B of the flow control valve 100 is connected to the first oil chamber 114. The check valve 104 allows the hydraulic oil to flow from the port A toward the second oil chamber 115 and prevents the hydraulic oil from flowing from the second oil chamber 115 toward the port A. The check valve 104 is a pilot check valve, and a pilot port is connected to a flow path between the first oil chamber 114 and the port B. When the hydraulic pressure between the first oil chamber 114 and port B (pilot port hydraulic pressure) exceeds a predetermined value, the check valve 104 allows the hydraulic oil to flow in the direction from the second oil chamber 115 toward the port A. To do.

  A supply port P of the flow control valve 100 is connected to the discharge side of the hydraulic pump 102. The hydraulic pump 102 is driven by a motor 121 and supplies hydraulic oil in the oil tank 103 on the suction side to the flow control valve 100 with a predetermined pressure. A discharge port T of the flow control valve 100 is connected to the oil tank 103.

  The flow rate control valve 100 performs flow path switching and flow rate control by the operating force supplied from the external operating force supply means 105. That is, the flow control valve 100 is connected to the neutral state in which both the port A and the port B are blocked with respect to the supply port P, and the PA that connects the supply port P and the port A and connects the port B and the discharge port T to each other. It functions as a direction switching valve capable of switching between the control state and the PB control state in which the supply port P and the port B are connected and the port A and the discharge port T are connected.

  In the neutral state, all of supply port P, port A, and port B are blocked by flow control valve 100. That is, the flow control valve 100 is configured to be fully closed in a neutral state. In the neutral state, since the hydraulic oil in the hydraulic cylinder 101 does not flow, the position of the rod 112 is maintained.

  In the PA control state, high-pressure hydraulic oil supplied from the hydraulic pump 102 passes through the supply port P and port A of the flow control valve 100 and flows into the second oil chamber 115 of the hydraulic cylinder 101 to push out the rod 112. . The hydraulic oil pushed out from the first oil chamber 114 passes through the port B and the discharge port T of the flow control valve 100 and is returned to the oil tank 103. The lifting hydraulic cylinder operates in the upward direction (vertically upward). In this case, the flow rate of the hydraulic oil (return oil) flowing out from the first oil chamber 114 is smaller than the flow rate of the hydraulic oil flowing into the second oil chamber 115. The difference in flow rate corresponds to the difference between the pressure receiving areas A1 and A2.

  In the PB control state, high-pressure hydraulic oil supplied from the hydraulic pump 102 passes through the supply port P and port B of the flow control valve 100 and flows into the first oil chamber 114 of the hydraulic cylinder 101 and pulls the rod 112. . The hydraulic oil pushed out from the second oil chamber 115 passes through the port A and the discharge port T of the flow control valve 100 and is returned to the oil tank 103. The lifting hydraulic cylinder operates in a descending direction (vertically downward). In this case, the flow rate of the hydraulic oil (return oil) flowing out from the second oil chamber 115 is larger than the flow rate of the hydraulic oil flowing into the first oil chamber 114. The difference in flow rate corresponds to the difference between the pressure receiving areas A1 and A2.

  In the PA control state and the PB control state, the flow rate control valve 100 controls the flow rate of the hydraulic oil from the port according to the position (movement amount) of the spool 2 (see FIG. 2) moved by the operating force. Is done. The position of the spool 2 corresponds to the magnitude of the operating force supplied from the operating force supply means 105. The operating force supply means 105 supplies an operating force to the flow control valve 100 in accordance with a control signal from the controller 106. The operating force supply means 105 is not particularly limited as long as it can apply an operating force to the spool. As the operating force supply means 105, for example, a method of supplying an operating force by an electromagnetic force such as a solenoid method, a method of supplying an operating force by a hydraulic pressure using a hydraulic pilot valve, or the like can be adopted. In the first embodiment, the hydraulic pressure of the hydraulic pump 102 is supplied to the pilot port 15 of the flow control valve 100 via the operating force supply means 105 including a hydraulic pilot valve, so that the operating force is supplied.

(Structure of flow control valve)
Next, a specific configuration example of the flow control valve 100 will be described with reference to FIGS.

  As shown in FIG. 2, the flow control valve 100 includes a body 1 provided with an oil passage through which hydraulic oil enters and exits, and a spool 2 that is held in the body 1 and moves by an operating force supplied from the outside. I have. The oil passage includes a supply port P to which hydraulic oil is supplied, a discharge port T from which hydraulic oil is discharged, and a port A and a port B that allow the hydraulic oil to flow in or out alternately. FIG. 2 shows a state in which the spool 2 is in the neutral position S0.

  The body 1 includes a spool chamber 11 in which the spool 2 is disposed, and a pair of pilot chambers 12 disposed on both sides of the spool chamber 11. The spool chamber 11 is a linear cylindrical internal space, and the spool 2 is slidably disposed along the axial direction (X direction). Each pilot chamber 12 is arranged on both sides of the spool chamber 11 in the axial direction of the spool 2.

  The supply port P, the discharge port T, the port A, and the port B pass through the body 1 from the outer periphery of the body 1 and communicate with the spool chamber 11. In the axial direction (X direction) of the spool 2, the supply port P is disposed in the center of the spool chamber 11, and the ports A and B are disposed on both sides of the supply port P, respectively. In the axial direction of the spool 2, the discharge port T is disposed outside the port A and the port B, respectively.

  Between the supply port P, the discharge port T, the port A, and the port B, a valve seat portion 13 formed of the inner peripheral surface of the spool chamber 11 (body 1) is provided. When the spool 2 is in a neutral position S0 (see FIG. 2) and a standby position S1 (see FIG. 6) to be described later, the valve seat portion 13 has an outer peripheral surface (sliding surface) 21 of the spool 2, a valve seat portion 13, Is configured to block the oil passage. That is, the valve seat portion 13 blocks the oil passages by facing the outer peripheral surface 21 of the spool 2 with a very small interval for the spool 2 to slide.

  The pilot chambers 12 on both sides in the axial direction are provided with pilot ports 15 for connection to the operating force supply means 105 (see FIG. 1). The pilot hydraulic pressure from the operating force supply means 105 is input to the pilot chamber 12 and acts as an operating force that moves the spool 2 in the spool chamber 11 in the axial direction (X direction).

(spool)
As shown in FIG. 3, the spool 2 is a roughly cylindrical shaft member. The spool 2 is provided with an outer peripheral surface 21 that is a sliding surface and a groove portion 22 for switching between the oil passages to a communication state. The groove portion 22 is formed at a predetermined depth over the entire circumference in the circumferential direction of the spool 2, and is disposed corresponding to the position of the supply port P and each discharge port T at the neutral position S0 (see FIG. 2). The groove 22 constitutes an oil passage that allows the port A or the port B to communicate with the supply port P or the discharge port T as the spool 2 moves. The two outer peripheral surfaces 21 between the groove portions 22 are formed so as to close the port A and the port B at the neutral position S0. The outer peripheral surfaces 21 at both ends of the spool 2 are provided so as to close the space between the pilot chamber 12 and the spool chamber 11.

  As shown in FIG. 4, the spool 2 moves in the first direction (X2 direction) to form a first opening 41 that allows the port B and the supply port P to communicate with each other, and also communicates the port A and the discharge port T. The second opening 42 to be formed is formed (PB control state). Further, as shown in FIG. 5, the spool 2 moves in the second direction (X1 direction) to form a third opening 43 that allows the port A and the supply port P to communicate with each other. The fourth opening 44 that is communicated is formed (set to the PA control state).

  The spool 2 includes a flow rate adjusting unit 23 (see FIG. 3) that forms an opening between the spool 2 and the body 1 as the spool 2 moves, and changes the opening area according to the amount of movement of the spool 2. The flow rate adjusting unit 23 has a function of making the flow rate of the hydraulic oil proportional to the amount of movement of the spool 2 by changing the opening area between the spool 2 and the body 1 as the spool 2 moves in the axial direction.

  As shown in FIG. 3, the flow rate adjusting portion 23 is provided at a boundary portion (step portion) between the three groove portions 22 and the two outer peripheral surfaces 21 therebetween. Further, a plurality of flow rate adjusting units 23 are provided at equal angular intervals in the circumferential direction of the spool 2. In the configuration example of FIG. 3, the flow rate adjusting unit 23 is a notch provided on the outer peripheral surface of the spool 2. Each flow rate adjusting portion 23 has a semicircular shape whose width (width in the circumferential direction) increases as it approaches the groove 22 side. The flow rate adjusting unit 23 forms a flow rate adjusting unit 23 a that forms the first opening 41, a flow rate adjusting unit 23 c that forms the third opening 43, a flow rate adjusting unit 23 b that forms the second opening 42, and a fourth opening 44. Including a flow rate adjusting unit 23d. The flow rate adjusting unit 23a and the flow rate adjusting unit 23c are examples of the “first flow rate adjusting unit” and the “second flow rate adjusting unit” in the claims, respectively.

  Here, as shown in FIG. 4, in the first embodiment, the opening area A <b> 11 of the first opening 41 is configured to be smaller than the opening area A <b> 12 of the second opening 42. That is, in the PB control state in which the port B and the supply port P are communicated, the opening area A11 of the first opening 41 between the port B and the supply port P is the opening of the second opening 42 between the port A and the discharge port T. It is smaller than area A12.

  The difference in opening area between the first opening 41 and the second opening 42 is realized by the difference in the shape of the flow rate adjusting unit 23. In the first embodiment, the flow rate adjusting unit 23 a is configured to form the first opening 41 with an opening area smaller than the opening area of the second opening 42. Specifically, the flow rate adjusting unit 23a and the flow rate adjusting unit 23b are formed so that the planar shapes of the notches are different from each other. The flow rate adjusting unit 23a is formed smaller than the flow rate adjusting unit 23b in a plan view (a state in which the notch is viewed from the front in the radial direction). The flow rate adjusting unit 23a has a circumferential width W1 smaller than a circumferential width W2 of the flow rate adjusting unit 23b. In other words, the area of the flow rate adjusting unit 23a in plan view is smaller than the area of the flow rate adjusting unit 23b.

  As shown in FIG. 4, when the flow rate adjusting unit 23a reaches the port B due to the movement of the spool 2 in the first direction (X2 direction), the first opening 41 is formed between the port B and the supply port P by the flow rate adjusting unit 23a. Is formed, and the second opening 42 is formed between the port A and the discharge port T (X2 side) by the flow rate adjusting unit 23b. The first opening 41 and the second opening 42 have different circumferential opening widths (W1, W2) due to the difference in width between the flow rate adjusting unit 23a and the flow rate adjusting unit 23b. As a result, the opening area A11 of the first opening 41 is smaller than the opening area A12 of the second opening 42. In FIG. 4, even if the spool 2 is further moved in the first direction (X2 direction) (even if the opening degree is changed), the magnitude relationship between the opening area A11 and the opening area A12 is maintained.

  In the first embodiment, the opening areas (A11, A12) of the first opening 41 and the second opening 42 are set based on the pressure receiving areas A1, A2 of the first oil chamber 114 and the second oil chamber 115, respectively. ing. For example, each opening area (A11, A12) has a ratio R1 (= A11 / A12) of the opening area A11 of the first opening 41 and the opening area A12 of the second opening 42 at an arbitrary opening degree. It is set to be approximately equal to the ratio R2 (= A1 / A2) of the pressure receiving area A1 of the chamber 114 and the pressure receiving area A2 of the second oil chamber 115.

  In the configuration example of FIG. 3, the flow rate adjusting unit 23c, the flow rate adjusting unit 23b, and the flow rate adjusting unit 23d other than the flow rate adjusting unit 23a have the same shape, and are all larger than the flow rate adjusting unit 23a. The length in the axial direction is the same in the flow rate adjusting unit 23a to the flow rate adjusting unit 23d. Thus, the flow rate adjusting unit 23a and the flow rate adjusting unit 23c have different shapes. The flow rate adjusting unit 23a and the flow rate adjusting unit 23c are formed so that the planar shapes of the notches are different from each other. The flow rate adjusting unit 23a is formed smaller than the flow rate adjusting unit 23c in plan view. The flow rate adjusting unit 23a has a circumferential width W1 smaller than the circumferential width W2 of the flow rate adjusting unit 23c.

  Therefore, in the first embodiment, the opening area of the first opening 41 per unit movement amount of the spool 2 in the first direction is the opening area of the third opening 43 per unit movement amount of the spool 2 in the second direction. It is comprised so that it may become smaller. As described above, the spool 2 of the first embodiment has an asymmetric shape in the axial direction (X direction).

  As shown in FIG. 5, when the flow rate adjusting unit 23c reaches the port A due to the movement of the spool 2 in the second direction (X1 direction), the third opening 43 is interposed between the port A and the supply port P by the flow rate adjusting unit 23c. And the fourth opening 44 is formed between the port B and the discharge port T by the flow rate adjusting unit 23d. The opening area A13 of the third opening 43 and the opening area A14 of the fourth opening 44 substantially coincide. In FIG. 5, even if the spool 2 is moved in the second direction (X1 direction) (the opening degree is changed), the opening area changes without changing the magnitude relationship between the opening area A13 and the opening area A14. .

  In the first embodiment, the respective opening areas (A11, A13) of the first opening 41 and the third opening 43 are set based on the pressure receiving areas A1, A2 of the first oil chamber 114 and the second oil chamber 115, respectively. ing. For example, each opening area (A11, A13) has a ratio R3 (= A11 / A13) between the opening area A11 of the first opening 41 and the opening area A13 of the third opening 43 at the same spool movement amount. It is set to be approximately equal to the ratio R2 (= A1 / A2) of the pressure receiving area A1 of the oil chamber 114 and the pressure receiving area A2 of the second oil chamber 115.

  Since the flow rate adjusting unit 23c, the flow rate adjusting unit 23b, and the flow rate adjusting unit 23d have the same shape, the rate of change of the opening area accompanying the movement of the spool 2 is the second opening 42, the third opening 43, and the fourth opening 44. equal. On the other hand, with respect to the first opening 41, the rate of change of the opening area accompanying the movement of the spool 2 is smaller than that of the other second opening 42 to the fourth opening 44. Thus, the rate of change of the opening area due to the movement of the spool 2 differs between the PB control state in which the port B and the supply port P are communicated and the PA control state in which the port A and the supply port P are in communication.

(Energizing Department)
Returning to FIG. 2, the body 1 is disposed on the first direction side (X2 direction side) of the spool 2, and is compressed with the movement of the spool 2 in the first direction, and the spool 2. And a second urging portion 30b which is arranged on the second direction side (X1 direction side) and is compressed as the spool 2 moves in the second direction. The body 1 holds the spool 2 in the neutral position S0 by the urging force of the first urging portion 30a and the second urging portion 30b. Thereby, the flow control valve 100 is maintained in the neutral state (fully closed state) when the operating force is not supplied. Further, the first urging portion 30a and the second urging portion 30b associate the operating force supplied from the operating force supply means 105 with the moving amount of the spool 2 by the urging force. When the input operating force exceeds a predetermined threshold, the spool 2 is formed between the ports by forming openings (the first opening 41 and the second opening 42 or the third opening 43 and the fourth opening 44) between the ports. Is reached in the control region S2 (see FIG. 7). In the control region S2, the hydraulic oil is increased by increasing the opening area of the opening (the first opening 41 and the second opening 42, or the third opening 43 and the fourth opening 44) as the moving amount of the spool 2 increases. Is proportional to the amount of movement of the spool 2.

  In addition to the state in which the spool 2 is held at the neutral position S0 and the state in which the control region S2 is moved, the flow rate control valve 100 is held at the standby position S1 between the neutral position S0 and the control region S2. A state is provided. By providing the standby position S1, it is possible to secure the distance of the seal portion between the valve seat portion 13 of the body 1 and the outer peripheral surface 21 of the spool 2 at the neutral position S0 (see FIG. 2). The leakage of hydraulic oil between the ports at S0 can be effectively reduced.

  Specifically, as shown in FIG. 2, each of the first urging portion 30a and the second urging portion 30b is compressed by the spool 2 between the neutral position S0 and the standby position S1. And a second spring 32 that is compressed by the spool 2 in the control region S2. Both the first spring 31 and the second spring 32 are compression coil springs. In the first embodiment, the spring constant of the first urging portion 30a and the spring constant of the second urging portion 30b are equal to each other. That is, the first spring 31 and the second spring 32 of the first biasing portion 30a and the first spring 31 and the second spring 32 of the second biasing portion 30b have the same spring constant. The spring constant of the second spring 32 is larger than the spring constant of the first spring 31.

  The body 1 further includes a first stopper 33 that restricts the movement of the spool 2 at the neutral position S0 and a second stopper 34 that restricts the movement of the spool 2 at the standby position S1. The first stopper 33 and the second stopper 34 are respectively disposed in the pair of pilot chambers 12. These springs and stoppers are arranged side by side in the order of the first stopper 33, the first spring 31, the second stopper 34, and the second spring 32 from the center side where the spool 2 is disposed to the outside. The first spring 31 is held in a state where one end side is in contact with the first stopper 33 and the other end side is in contact with the second stopper 34. The second spring 32 is held in a state where one end is in contact with the second stopper 34 and the other end is in contact with the inner surface of the body 1.

  The first stopper 33 is urged toward the spool 2 by the first spring 31 and is pressed against the first positioning portion 16 that is a part of the body 1. The first stopper 33 is disposed by the first positioning portion 16 at a position substantially equal to the axial end surface of the spool 2 at the neutral position S0. By disposing the first stoppers 33 on both sides of the spool 2 in the axial direction, the spool 2 is held at the neutral position S0. When an operating force larger than the first threshold value TH1 is applied to the spool 2, the first spring 31 is compressed together with the first stopper 33.

  The second stopper 34 is biased toward the spool 2 by the second spring 32 and is pressed against the second positioning portion 17 that is a part of the body 1. The second stopper 34 is disposed by the second positioning portion 17 so as to hold the spool 2 at the standby position S1. That is, when the spool 2 moves and compresses the first spring 31, the first stopper 33 and the second stopper 34 come into contact with each other to reach a standby position S1 (see FIG. 6) where the movement of the spool 2 is restricted. . When an operating force larger than the second threshold value TH2 is applied to the spool 2, the second spring 32 is compressed together with the second stopper 34. In order to move the spool 2 to the standby position S1, the increase in the biasing force (spring constant) by compressing the first spring 31 by the first threshold value TH1 and the movement distance between the neutral position S0 and the standby position S1. K1 × travel distance) and the total operating force is required. The second threshold value TH2 is set to a value larger than the first threshold value TH1 + the biasing force increase (spring constant K1 × movement distance).

  When the spool 2 moves and compresses the second spring 32, the spool 2 reaches the control region S2 (see FIG. 7). When the spool 2 reaches the control region S2 on the first direction (X2 direction) side as shown in FIG. 7, the first opening 41 and the second opening 42 are formed, and the PB control state shown in FIG. Similarly, when the spool 2 reaches the control region S2 on the second direction (X1 direction) side, the third opening 43 and the fourth opening 44 are formed, and the PA control state shown in FIG. 5 is established.

  Each of the first stopper 33 and the second stopper 34 is provided with a through hole 35 (see FIG. 2) for allowing hydraulic oil to pass therethrough. For this reason, when hydraulic fluid is supplied to the pilot chamber 12 in order to apply the operational force, the hydraulic fluid acts on the spool 2 through the through hole 35.

  With such a configuration, the spool 2 moves to the neutral position S0, the standby position S1, and the control area S2.

(Operation of flow control valve)
Next, the operation of the flow control valve 100 according to the first embodiment will be described using a comparative example shown in FIG.

<Comparative example>
The spool 80 of the comparative example shown in FIG. 8 has a left-right symmetrical shape in which all the flow rate adjusting portions 83 have the same shape and the same dimensions. That is, in the comparative example, when the opening areas of the first opening 41 to the fourth opening 44 formed by the respective flow rate adjusting units 83 are A21 to A24, the opening areas A21 to A24 are all equal. Is shown. In this case, as shown in FIG. 9, in the PB control state, the opening area A21 of the first opening 41 and the opening area A22 of the second opening 42 coincide. Similarly, the opening area A23 of the third opening 43 coincides with the opening area A24 of the fourth opening 44 in the PA control state. Further, the amount of change in the opening area per unit movement amount of the spool 2 is equal between the PA control and the PB control.

  When the flow control valve having the spool 80 according to the comparative example is connected to the hydraulic cylinder 101, in the PA control state, hydraulic oil is sent from the port A to the second oil chamber 115, and the first oil chamber is raised as the rod 112 rises. The hydraulic oil (return oil) flows into port B from 114. Since the pressure receiving area A1 of the first oil chamber 114 is smaller than the pressure receiving area A2 of the second oil chamber 115 by the amount of the rod 112, the flow rate of the hydraulic oil sent from the port A to the second oil chamber 115 is the first to the port B. It becomes larger than the flow rate of the return oil from one oil chamber 114. Since the opening degree of the flow rate control valve is adjusted according to the flow rate of the hydraulic fluid on the discharge side, when the opening degree of the third opening 43 (opening area A23) on the discharge side is adjusted according to the flow rate, the return side control valve The opening area A24 of the four openings 44 is in a relatively large state with respect to the flow rate of the return oil. As a result, in the PA control, on the fourth opening 44 side where the flow rate of the return oil is small, the hydraulic pressure does not increase and the pressure loss is kept low.

  On the other hand, in the PB control state, the flow rate of the hydraulic oil sent from the port B (first opening 41) to the first oil chamber 114 returns the hydraulic oil (return) from the second oil chamber 115 to the port A (second opening 42). Oil) flow rate. In the comparative example, when the opening degree of the first opening 41 (opening area A21) on the discharge side is adjusted according to the flow rate, the opening area A22 of the second opening 42 on the return side is relative to the flow rate of the return oil. It becomes a small state. As a result, on the second opening 42 side where the flow rate of the return oil is large, the hydraulic pressure increases and the pressure loss increases. Thus, in the comparative example, the pressure loss is larger in the PB control than in the PA control.

<Flow control valve of the first embodiment>
On the other hand, in the flow control valve 100 of the first embodiment, as shown in FIG. 10, in the PB control state, the opening degree of the first opening 41 according to the flow rate of the working oil sent to the first oil chamber 114. When the (spool movement amount) is adjusted, the opening area A12 of the second opening 42 becomes larger than the opening area A11 of the first opening 41 (A11 <A12, see FIG. 4). Therefore, even when the flow rate of the return oil from the second oil chamber 115 is larger than the flow rate of the hydraulic oil to the first oil chamber 114 due to the difference in pressure receiving area, a sufficient opening area is secured in the second opening 42. Is done.

  In FIG. 10, it is assumed that the ratio R2 (= A1 / A2) between the pressure receiving area A1 of the first oil chamber 114 and the pressure receiving area A2 of the second oil chamber 115 is 1/2. The flow rate returned from the second oil chamber 115 is double the discharge flow rate to the first oil chamber 114.

  Therefore, in the first embodiment, the ratio R1 (= A11 / A12) of the opening area A11 of the first opening 41 and the opening area A12 of the second opening 42 is set to 1/2. As a result, the opening area A12 with respect to the opening area A11 is also doubled, and even on the second opening 42 side where the flow rate of return oil is large, the hydraulic pressure does not increase and unnecessary pressure loss does not occur.

  Note that, in the PA control state, the flow rate of the return oil is relatively small, so the opening degree (spool movement amount) of the third opening 43 is adjusted according to the discharge flow rate of the hydraulic oil to the second oil chamber 115. Then, the opening area A14 of the fourth opening 44 is relatively large with respect to the flow rate of the return oil (see FIG. 5). As a result, as in the comparative example, on the fourth opening 44 side where the flow rate of the return oil is small, the hydraulic pressure does not increase and the pressure loss is kept low.

  Thus, in the first embodiment, the pressure loss does not increase even in the PB control.

  Next, referring to FIG. 11, the cylinder speed (moving speed of rod 112) in each of PA control (rod extension control) and PB control (rod pull-in control) will be compared.

  In the comparative example, since the spool 80 has a symmetrical shape, the opening area A21 of the first opening 41 in the PB control and the opening area A23 of the third opening 43 in the PA control are mutually equal when the movement amount of the spool 80 is the same. (Refer to FIG. 9), the discharge flow rate of the port B in the PB control and the discharge flow rate of the port A in the PA control coincide.

  In this case, on the hydraulic cylinder 101 side, the cylinder speed per unit flow rate is increased by the rod extension due to the difference (A1 <A2) between the pressure receiving area A1 of the first oil chamber 114 and the pressure receiving area A2 of the second oil chamber 115. It will be different depending on when the rod is retracted. That is, in the case of the comparative example, the cylinder speed on the PA control side and the cylinder speed on the PB control side at the same movement amount of the spool 80 do not match.

  Therefore, in the first embodiment, the ratio R3 (= A11 / A13) of the opening area A11 of the first opening 41 and the opening area A13 of the third opening 43 at the same spool movement amount is the pressure receiving area ratio R2 = Set to 1/2. As a result, when the amount of movement of the spool 2 is the same, the discharge flow rate at the port A in the PA control is twice the discharge flow rate at the port B in the PB control. Thereby, in the case of 1st Embodiment, the cylinder speed in the same movement amount of the spool 2 corresponds by the PA control side and the PB control side.

(Effect of 1st Embodiment)
In the first embodiment, the following effects can be obtained.

  In the first embodiment, as described above, by moving in the first direction (X2 direction), the first opening 41 for communicating the port B and the supply port P is formed, and the port A and the discharge port are communicated. The spool 2 that forms the second opening 42 is provided, and the flow control valve 100 is configured such that the opening area A11 of the first opening 41 is smaller than the opening area A12 of the second opening 42. Thereby, the opening area A11 of the first opening 41 through which the hydraulic oil flowing out from the supply port P through the port B passes can be relatively reduced, and the return oil returns to the discharge port T through the port A. The opening area A12 of the second opening 42 through which can pass can be made relatively large. Therefore, if the first oil chamber 114 having a smaller pressure receiving area (or volume change amount) is connected to the port B and the second oil chamber 115 having the larger pressure receiving area is connected to the port A, the supplied hydraulic oil is supplied. Even if the flow rate of the return oil is increased by the difference in the pressure-receiving area from the flow rate, the opening area A12 of the second opening 42 through which the return oil passes can be relatively increased. Even when the flow rate of the hydraulic oil is different on the return side, it is possible to suppress an increase in the pressure of the hydraulic oil.

  In the first embodiment, as described above, the spool 2 is provided with the flow rate adjusting unit 23a that forms the first opening 41 with the opening area A11 smaller than the opening area A12 of the second opening 42. Thereby, the opening area A11 of the first opening 41 can be easily changed to the opening area A12 of the second opening 42 by simply changing the shape of the flow rate adjusting portion 23a of the spool 2 for adjusting the flow rate according to the movement amount. On the other hand, it can be made relatively small.

  In the first embodiment, as described above, the opening areas A11 of the first opening 41 and the second opening 42 are based on the pressure receiving areas A1 and A2 of the first oil chamber 114 and the second oil chamber 115, respectively. , A12 is set. Accordingly, the difference between the opening areas A11 and A12 of the first opening 41 and the second opening 42 is determined according to the difference between the pressure receiving areas A1 and A2 between the first oil chamber 114 and the second oil chamber 115. It becomes possible to do. That is, since the flow rate on the return side (second opening 42 side) with respect to the flow rate on the supply side (first opening 41 side) is known based on the pressure receiving areas A1 and A2, the opening area corresponding to the flow rate difference is set to the first opening 41. And by setting to the 2nd opening 42, it can suppress more effectively that the pressure of hydraulic fluid rises.

  In the first embodiment, as described above, the opening area A11 of the first opening 41 per unit movement amount of the spool 2 in the first direction (X2 direction) is set to the spool in the second direction (X1 direction). It is configured to be smaller than the opening area A13 of the third opening 43 per unit movement amount of 2. As a result, the discharge flow rate of the hydraulic oil to each oil chamber (114, 115) can be varied according to the difference in pressure receiving area (A1, A2), so that the rod extension control (PA control) and the rod pull-in The difference in the moving speed of the rod 112 with the same spool movement amount can be reduced during control (PB control). In particular, as in the first embodiment, the ratio R3 (= A11 / A13) of the opening area A11 of the first opening 41 and the opening area A13 of the third opening 43 with the same spool movement amount is set to the first oil chamber. 114 is set to be substantially equal to the ratio R2 (= A1 / A2) between the pressure receiving area A1 of 114 and the pressure receiving area A2 of the second oil chamber 115, the PA control side and the PB control side The moving speed (see FIG. 11) of the rod 112 at the same moving amount can be matched.

  Further, in the first embodiment, as described above, the flow rate adjusting unit 23 a that forms the first opening 41 in the spool 2 and the flow rate that has a different shape from the flow rate adjusting unit 23 a and forms the third opening 43. An adjustment unit 23c is provided. Accordingly, the opening area A11 of the first opening 41 can be easily made relatively to the opening area A13 of the third opening 43 only by changing the shapes of the flow rate adjusting part 23a and the flow rate adjusting part 23c of the spool 2. Can be small.

  Further, in the first embodiment, as described above, the flow rate adjusting unit 23 is formed as a notch provided on the outer peripheral surface of the spool 2, and the flow rate adjusting unit 23a and the flow rate adjusting unit 23c have a planar shape of the notch. They are formed differently. Thereby, the structure which makes opening area A11, A13 different can be easily implement | achieved by making the planar shape of a notch differ in the flow volume adjustment part 23a and the flow volume adjustment part 23c.

(First modification of the first embodiment)
In the first embodiment, the flow rate adjusting unit 23a and the flow rate adjusting unit 23c of the spool 2 are formed so that the planar shapes of the notches are different from each other. However, the first modification shown in FIGS. In the example, the dimensions of the notch are different.

  Specifically, in the spool 202 of the first modification, the flow rate adjusting unit 223a and the flow rate adjusting unit 223c have different notch depths. The notch has the same shape as the keyway, and the bottom surface is flat (a plane perpendicular to the radial direction of the spool). The depth of the notch is the maximum depth of the spool 202 in the radial direction. As the depth of the cutout increases, the opening size between the body 1 and the spool 202 when the opening is formed by the flow rate adjusting unit 223 increases, and thus the opening area increases. The flow rate adjusting unit 223a and the flow rate adjusting unit 223c are examples of the “first flow rate adjusting unit” and the “second flow rate adjusting unit” in the claims, respectively.

  As shown in FIG. 13, the depth D1 of the flow rate adjusting unit 223a is smaller than the depth D2 of the flow rate adjusting unit 223c. As a result, the opening area A11 of the first opening 41 per unit movement amount of the spool 202 in the first direction (X2 direction) is the third opening per unit movement amount of the spool 2 in the second direction (X1 direction). 43 is configured to be smaller than the opening area A13. In the first modification, the flow rate adjusting unit 223b and the flow rate adjusting unit 223d also have a depth D2. Therefore, the opening area A11 of the first opening 41 is smaller than the opening area A12 of the second opening 42.

(Effect of the first modification)
In the first modification of the first embodiment, as described above, the flow rate adjusting unit 223a and the flow rate adjusting unit 223c are formed so that the notch dimensions (depth dimensions) are different from each other. Thus, the structure which makes opening area A11, A13 different can be easily implement | achieved by varying the depth dimension of a notch with the flow volume adjustment part 223a and the flow volume adjustment part 223c.

(Second modification of the first embodiment)
In the first embodiment and the first modified example, the example in which the flow rate adjusting unit 23 (223) of the spool 2 is configured by a notch is shown. However, in the second modified example shown in FIGS. Reference numeral 323 denotes a tapered portion.

  Specifically, in the spool 302 of the second modified example, each flow rate adjusting portion 323 is a tapered portion formed so as to reduce the outer diameter of the outer peripheral surface 21 of the spool 2. Here, the flow rate adjusting unit 323 is a linear taper with a constant inclination angle, and is formed over the entire circumference of the spool 302. As the inclination angle of the taper portion increases, the opening size between the body 1 and the spool 302 when the opening is formed by the flow rate adjusting portion 323 increases, and thus the opening area increases.

  As shown in FIG. 15, the flow rate adjusting unit 323a and the flow rate adjusting unit 323c are formed so that the inclination angles of the tapered portions are different from each other. That is, the inclination angle θ1 of the flow rate adjustment unit 323a is smaller than the inclination angle θ2 of the flow rate adjustment unit 323c. As a result, the opening area A11 of the first opening 41 per unit movement amount of the spool 302 in the first direction (X2 direction) is the third opening per unit movement amount of the spool 2 in the second direction (X1 direction). 43 is configured to be smaller than the opening area A13. In the second modification, the flow rate adjustment unit 323b and the flow rate adjustment unit 323d also have the inclination angle θ2. Therefore, the opening area A11 of the first opening 41 is smaller than the opening area A12 of the second opening 42. The flow rate adjustment unit 323a and the flow rate adjustment unit 323c are examples of the “first flow rate adjustment unit” and the “second flow rate adjustment unit” in the claims, respectively.

(Effect of the second modification)
In the second modification of the first embodiment, as described above, the flow rate adjustment portion 323 is a tapered portion formed so as to reduce the outer diameter of the outer peripheral surface 21 of the spool 2. And the flow volume adjustment part 323a and the flow volume adjustment part 323c are formed so that the inclination angle of a taper part may mutually differ. Thereby, the structure which makes the opening areas A11 and A13 different can be easily implement | achieved by varying the inclination-angle of a taper part with the flow volume adjustment part 323a and the flow volume adjustment part 323c.

[Second Embodiment]
Next, with reference to FIG. 16 and FIG. 17, the flow control valve 400 by 2nd Embodiment of this invention is demonstrated. In the second embodiment, unlike the first embodiment in which the first biasing portion 330a and the second biasing portion 330b have the same spring constant, the first biasing portion 330a and the second biasing portion. An example in which the spring constant is changed from 330b will be described. In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals and the description thereof is omitted.

  As shown in FIG. 16, in the flow control valve 400 of the second embodiment, the spring constant of the first biasing portion 330a that is compressed as the spool 2 moves in the first direction (X2 direction) is the second. This is smaller than the spring constant of the second urging portion 330b compressed as the spool 2 moves in the direction (X1 direction).

  Specifically, the spring constant K1 of the second spring 332a of the first biasing part 330a is different from the spring constant K2 of the second spring 332b of the second biasing part 330b. Since the spring constant of the second spring 332a (332b) is different, the movement amount of the spool 2 with respect to the operating force in the control region S2 is different between the first direction side (port B side) and the second direction side (port A side). Is different. Note that the spring constant of the first spring 31 is equal between the first biasing portion 330a and the second biasing portion 330b.

  The spring constant K1 of the second spring 332a of the first biasing portion 330a is smaller than the spring constant K2 of the second spring 332b of the second biasing portion 330b. As a result, in the second embodiment, when the port is opened with the same operating force, the movement amount of the spool 2 in the PB control state is larger than the movement amount of the spool 2 in the PA control state. As a result, the rate of change of the opening degree of the first opening 41 in the PB control state becomes larger than the rate of change of the opening degree of the third opening 43 in the PA control state.

  The spring constants of the first urging portion 330a and the second urging portion 330b are set based on the opening area A11 of the first opening 41 and the opening area A13 of the third opening 43. That is, in each of the PA control state and the PB control state, when the same flow rate command is input to the controller 106, the opening area A11 of the first opening 41 and the opening area A13 of the third opening 43 are substantially matched. In addition, spring constants K1 and K2 of the second springs 332a (332b) of the first biasing portion 330a and the second biasing portion 330b are set. Specifically, each of the second springs is substantially matched to a ratio R3 (= A11 / A13) of the opening area A11 of the first opening 41 and the opening area A13 of the third opening 43 at the same movement amount of the spool 2. Spring constants K1 and K2 of 332a (332b) are set.

  For example, as shown in FIG. 17, it is assumed that the ratio R3 (= A11 / A13) of the opening area A11 of the first opening 41 and the opening area A13 of the third opening 43 at the same movement amount is 1: 2. In this case, the spring constants K1 and K2 of the second springs 332a (332b) are set to have a 1: 2 relationship. In the PA control state and the PB control state, when the same flow command is input to the controller 106, the same operating force is supplied to the spool 2. When the spring constants K1 and K2 of the second springs 332a (332b) are in a 1: 2 relationship, the movement amount (opening) of the spool 2 in the second direction in the PA control state and the PB control state The ratio of the amount of movement (opening) of the spool 2 in the first direction is the reciprocal (2: 1) of R3. That is, the opening degree in the PB control state is twice that in the PA control state. As a result, in the PA control state and the PB control state, the opening area A11 of the first opening 41 and the opening area A13 of the third opening 43 for the same flow command (operating force) coincide.

  As described above, in the flow rate control valve 400 of the second embodiment, the discharge flow rate in the PA control state (the flow rate of hydraulic oil from the port A) and the PB control state in response to the same flow rate command (operating force). The discharge flow rate (the flow rate of hydraulic oil from the port B) is substantially the same. Other configurations of the second embodiment are the same as those of the first embodiment.

(Effect of 2nd Embodiment)
In the second embodiment, similarly to the first embodiment, the opening area A11 of the first opening 41 is made smaller than the opening area A12 of the second opening 42, so that the hydraulic oil is supplied on the supply side and the return side. Even when the flow rates are different, an increase in the pressure of the hydraulic oil can be suppressed.

  In the second embodiment, as described above, the spring constant (K1) of the first biasing portion 330a is made smaller than the spring constant (K2) of the second biasing portion 330b. Thereby, the spool 2 can be easily moved in the first direction (X2 direction). Therefore, since the opening area A11 of the first opening 41 per unit movement amount when the spool 2 is moved in the first direction (X2 direction) is small, the opening degree of the port B (opening area A11 of the first opening 41) is reduced. The flow rate can be ensured by increasing the flow rate. As a result, the discharge flow rate from the port B or the port A when the same operating force is supplied to the spool 2 in the first direction (X2 direction) and the second direction (X1 direction) can be made closer to each other. When it is desired to control the flow rate itself when the port is opened, the flow rates can be easily adjusted.

  The effect of the second embodiment is the same as that of the first embodiment.

[Third Embodiment]
Next, with reference to FIG. 1 and FIG. 18, the flow control valve 500 (refer FIG. 1) by 3rd Embodiment of this invention is demonstrated. In the third embodiment, unlike the second embodiment in which the first urging portion 330a and the second urging portion 330b have different spring constants, the operating force supplied to the flow control valve 500 is different. Thus, an example in which the discharge flow rates during PA control and PB control are aligned will be described. Note that in the third embodiment, the same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  In the flow control valve 500 (see FIG. 1) of the third embodiment, the same spring constant (first spring) is used in the first urging unit 30a and the second urging unit 30b as in the first embodiment. 31 and the spring constant of the second spring 32) are set. Therefore, the movement amount of the spool 2 with respect to the same operating force is equal in the PA control state (second direction, X1 direction) and the PB control state (first direction, X2 direction).

  As shown in FIG. 1, the flow control valve 500 of the third embodiment is configured such that the controller 506 controls the operating force supplied to the spool 2 and the gradient of the supplied operating force with respect to the flow rate command value in the second direction (X1 direction). The gradient Δf1 of the supply operating force with respect to the flow rate command value in the first direction (X2 direction) is larger than Δf2. That is, in the controller 506, the characteristics of the supply operating force with respect to the flow rate command value differ between PA control and PB control.

  Specifically, as shown in FIG. 18, the controller 506 makes the gradient of the supply operating force with respect to the flow rate command value larger in the first direction (Δf1) than in the second direction (Δf2). In other words, when the same flow rate command is input, the controller 506 makes the supply operation force during the PB control larger than the supply operation force during the PA control.

  When the same flow rate command value is input, the controller 506 determines the supply operating force in the first direction so that the opening area A11 of the first opening 41 substantially matches the opening area A13 of the third opening 43. The inclination Δf1 is set larger than the inclination Δf2 of the supply operating force in the second direction. The controller 506 determines that the ratio (= Δf2 / Δf1) between the supply operation force in the second direction and the supply operation force in the first direction when the same flow rate command value is input is the opening area of the first opening 41. It is configured to substantially coincide with a ratio R3 (= A11 / A13) between A11 and the opening area A13 of the third opening 43.

  In FIG. 18, it is assumed that the ratio R3 (= A11 / A13) of the opening area A11 of the first opening 41 and the opening area A13 of the third opening 43 at the same movement amount is 1: 2. In this case, when the same flow rate command is input to the controller 506 in the PA control state (inclination Δf2) and the PB control state (inclination Δf1), the supply operating force has a 1: 2 relationship, and the spool in the PA control state The ratio of the movement amount (opening) of 2 to the movement amount (opening) in the PB control state is R3. As a result, in the PA control state and the PB control state, the opening area A11 of the first opening 41 and the opening area A13 of the third opening 43 for the same flow command (operating force) coincide.

  As described above, in the flow control valve 500 of the third embodiment, the discharge flow rate in the PA control state (the flow rate of hydraulic oil from the port A) and the discharge flow rate in the PB control state (with respect to the same flow rate command) The flow rate of the hydraulic oil from the port B) is substantially matched.

  Other configurations of the third embodiment are the same as those of the first embodiment.

(Effect of the third embodiment)
In the third embodiment, similarly to the first embodiment, the opening area A11 of the first opening 41 is made smaller than the opening area A12 of the second opening 42, so that the hydraulic oil is supplied on the supply side and the return side. Even when the flow rates are different, an increase in the pressure of the hydraulic oil can be suppressed.

  Further, in the third embodiment, as described above, the controller 506 that controls the operating force supplied to the spool 2 causes the first operating force gradient Δf2 relative to the flow rate command value in the second direction (X1 direction). The flow rate control valve 500 is configured such that the gradient Δf1 of the supply operating force with respect to the flow rate command value in one direction (X2 direction) is increased. Thereby, when opening or closing the port B or the port A with the same flow command value, the opening degree of the port B (opening area A11 of the first opening 41) can be further increased. As a result, the flow rate from port B or port A when opening and closing with the same flow rate command value can be made close, so that it is easy to align the flow rate when it is desired to control the flow rate itself when each port is opened. it can.

  The effect of the third embodiment is the same as that of the first embodiment.

[Modification]
The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiment but by the scope of claims for patent, and further includes all modifications (modifications) within the meaning and scope equivalent to the scope of claims for patent.

  For example, in the first to third embodiments, the example in which the standby position S1 is provided between the neutral position S0 and the control region S2 in the operation range of the spool 2 has been described, but the present invention is not limited thereto. . In the present invention, unlike the flow control valve 600 according to the modification shown in FIGS. 19 and 20, the standby position S1 does not have to be provided between the neutral position S0 and the control region S2.

  In the flow control valve 600 shown in FIGS. 19 and 20, the standby position S1 is not provided between the neutral position S0 and the control region S2. As shown in FIG. 20, the flow control valve 600 is configured to immediately reach the control region S2 (port B side) and enter the PB control state when the spool 602 moves in the X2 direction from the neutral position S0. . Similarly, if the spool 602 moves in the X1 direction from the neutral position S0, it immediately reaches the control region S2 (port A side) and enters the PA control state.

  In the configuration in which the standby position S1 is not provided, it is only necessary to provide one spring 631 as shown in FIG. 19 without providing the first spring 31 and the second spring 32. That is, in the flow control valve 600, each of the first urging portion 630a and the second urging portion 630b includes one spring 631 and one stopper 632. A spring 631 biases the stopper 632 toward the positioning portion 611 of the body 1. The spool 602 is provided with a stepped portion 625, and the stepped portion 625 engages with the stopper 632 to move the stopper 632 when moving in the X direction by the operating force. The spool 602 moves to the control region S2 by moving the stopper 632 against the urging force of the spring 631.

  In the first embodiment and each modification, the example in which the four flow rate adjusting units 23 (223, 323) are provided in the spool 2 (202, 302) has been described, but the present invention is not limited to this. In the present invention, like the flow control valve 600 shown in FIG. 19, only two flow rate adjusting units 623 may be provided. In FIG. 19, a flow rate adjusting unit 623 a for forming the first opening 41 and a flow rate adjusting unit 623 c for forming the third opening 43 are provided, and correspond to the second opening 42 and the fourth opening 44. There is no flow rate adjustment unit to perform. The flow rate adjustment unit 623a and the flow rate adjustment unit 623c are examples of the “first flow rate adjustment unit” and the “second flow rate adjustment unit” in the claims, respectively.

  In this case, in the PB control state of FIG. 20, the supply port P and the port B communicate with each other through the first opening 41 formed by the flow rate adjusting unit 623 a, and the port A and the discharge port T are the outer peripheral surface of the spool 602. The second opening 642 is formed by a step (boundary portion) between the groove 21 and the groove 22. Also in this case, the flow control valve 600 is configured such that the second opening 642 is larger than the first opening 41. Although the description is omitted, the same applies to PA control.

  In the first embodiment and each modification, the example in which the four flow rate adjusting units 23 (223, 323) are provided in the spool 2 (202, 302) has been described, but the present invention is not limited to this. In the present invention, instead of providing the spool 2 with a flow rate adjusting portion, a flow rate adjusting portion may be provided on the inner surface (valve seat portion 13) of the body 1. For example, a notch similar to the flow rate adjusting portion 23 is formed in the opening portion of the port A (a boundary portion with the valve seat portion 13), and the opening is formed when the boundary of the groove portion 22 reaches the notch by the movement of the spool 2. The flow control valve may be configured as described.

  Moreover, in the said 1st Embodiment, although the flow volume adjustment part 23 showed the example made into the semicircle notch, this invention is not limited to this. As long as the amount of movement of the spool is proportional to the opening area of the opening formed by the flow rate adjusting unit, the notch shape (the shape of the flow rate adjusting unit) is arbitrary, and may be, for example, a triangular shape or a square shape. .

  Moreover, in the said 1st Embodiment (refer FIG. 3), the example which makes the plane shape of a notch mutually differ in the flow volume adjustment part 23a and the flow volume adjustment part 23c is shown, and the 1st modification (FIG. 12) shows an example in which the dimensions (depths) of the notches are made different from each other, and in the second modified example of the first embodiment (see FIG. 14), an example in which the inclination angles of the tapered portions are made different from each other is shown. . However, the present invention is not limited to this. In addition to these configuration examples, in the present invention, for example, the number of notches may be different between the flow rate adjusting unit 23a and the flow rate adjusting unit 23c. For example, two flow rate adjusters 23a are formed in the circumferential direction, and three or more flow rate adjusters 23c are formed in the circumferential direction. In this case, the opening area A13 of the third opening 43 formed by the flow rate adjusting unit 23c is larger than the opening area A11 of the first opening 41 formed by the flow rate adjusting unit 23a, as the number of notches formed increases. Can be increased.

  In the first to third embodiments, the opening area A11 of the first opening 41 per unit movement amount of the spool 2 in the first direction (PB control state) is the second direction (PA control state). Although an example in which the opening area A13 of the third opening 43 per unit movement amount of the spool 2 is smaller is shown, the present invention is not limited to this. In the present invention, the opening area A11 and the opening area A13 per unit movement amount may be equal. In this case, the flow rate adjusting unit 23a and the flow rate adjusting unit 23c may have the same shape and the same dimensions.

1 Body 2, 202, 302, 602 Spool 23, 223, 323, 623 Flow rate adjustment unit 23a, 223a, 323a, 623a Flow rate adjustment unit (first flow rate adjustment unit)
23c, 223c, 323c, 623c Flow rate adjustment unit (second flow rate adjustment unit)
30a, 330a, 630a 1st urging part 30b, 330b, 630b 2nd urging part 41 1st opening 42, 642 2nd opening 43 3rd opening 44 4th opening 100, 400, 500, 600 Flow control valve 106, 506 Controller A port (second port)
B port (1st port)
P supply port T discharge port

Claims (9)

A body including a supply port to which the hydraulic oil is supplied, a discharge port from which the hydraulic oil is discharged, and a first port and a second port that allow the hydraulic oil to flow in or out alternately.
A spool held in the body and moved by an operating force supplied from the outside,
The spool moves in the first direction to form a first opening for communicating the first port and the supply port, and a second opening for communicating the second port and the discharge port. Composed of
A flow rate control valve configured such that an opening area of the first opening is smaller than an opening area of the second opening. The spool includes a flow rate adjusting unit that forms an opening between the spool and the body as the spool moves, and changes an opening area according to the amount of movement of the spool.
2. The flow control valve according to claim 1, wherein the flow rate adjusting unit includes a first flow rate adjusting unit that forms the first opening with an opening area smaller than an opening area of the second opening. The first port and the second port are respectively connected to a first oil chamber and a second oil chamber having different pressure receiving areas in the hydraulic cylinder,
The flow rate control valve according to claim 1 or 2, wherein each opening area of the first opening and the second opening is set based on a pressure receiving area of each of the first oil chamber and the second oil chamber. . The spool moves in the second direction so as to form a third opening for communicating the second port and the supply port and a fourth opening for communicating the first port and the discharge port. Configured,
The opening area of the first opening per unit movement amount of the spool in the first direction is smaller than the opening area of the third opening per unit movement amount of the spool in the second direction. The flow control valve according to claim 1, which is configured. The spool includes a flow rate adjusting unit that forms an opening between the spool and the body as the spool moves, and changes an opening area according to the amount of movement of the spool.
The flow rate adjustment unit includes: a first flow rate adjustment unit that forms the first opening; and a second flow rate adjustment unit that has a shape or dimension different from that of the first flow rate adjustment unit and that forms the third opening. The flow control valve according to claim 4 comprising:   The flow rate adjusting part is a notch provided on the outer peripheral surface of the spool, and the first flow rate adjusting part and the second flow rate adjusting part are formed so that the planar shape or depth of the notch is different from each other. The flow control valve according to claim 5.   The flow rate adjusting portion is a tapered portion formed so as to reduce the outer diameter of the outer peripheral surface of the spool, and the first flow rate adjusting portion and the second flow rate adjusting portion have an inclination angle of the tapered portion with each other. The flow control valve according to claim 5, wherein the flow control valve is formed differently. The body is disposed on the first direction side of the spool, and is disposed on the second direction side of the spool, and a first urging portion that is compressed as the spool moves in the first direction. A second urging portion that is compressed as the spool moves in the second direction,
The flow control valve according to any one of claims 4 to 7, wherein a spring constant of the first urging portion is smaller than a spring constant of the second urging portion.   The controller that controls the operating force supplied to the spool causes the gradient of the supplied operating force with respect to the flow rate command value in the first direction to be larger than the gradient of the supplied operating force with respect to the flow rate command value in the second direction. The flow control valve according to any one of claims 4 to 7, which is configured as follows.

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