JP2019173875A - Solenoid proportional control valve - Google Patents

Abstract

An object of the present invention is to improve the accuracy of a secondary pressure (control pressure). An electromagnetic proportional control valve (100) includes a housing (1), a sleeve (3) housed in the housing (1), a spool (5) provided in the sleeve (3), and a thrust Fa due to a secondary pressure acting in an axial direction; A spring 7 that applies a thrust Fs to one end of the spool 5, a spring 4 that applies a biasing force Fk against the thrust Fs by the solenoid 7 to the other end of the spool 5, and an adjustment mechanism that adjusts the biasing force Fk of the spring 4 with respect to the spool 5. 9, the pressure (secondary pressure) of the secondary pressure port 12 is controlled by the balance of the thrust Fs, the urging force Fk, and the thrust Fa with respect to the spool 5, and the secondary pressure port 12 with respect to the primary pressure port 11 and the tank port 13. The adjusting mechanism 9 has a spring receiving portion 84 for holding the spring 4 between the other end of the spool 5 and the spring receiving portion 84. By changing the to adjust the biasing force of the spring 4. [Selection diagram] Fig. 1

Description

  The present invention relates to an electromagnetic proportional control valve.

  Patent Document 1 discloses an electromagnetic proportional control that controls a pressure output to a controlled device by driving a spool against a load (biasing force) generated by a spring by supplying a control current to an electromagnetic actuator. A valve is disclosed.

JP 2017-180641 A

  However, in the electromagnetic proportional control valve described in Patent Document 1, the initial load of the spring on the spool is affected by variations in spring set length in addition to variations in spring manufacture. Further, the spring load on the spool when the output pressure (secondary pressure) is held is affected by variations in the stroke amount of the spool in addition to the above variations. For this reason, in the electromagnetic proportional control valve described in Patent Document 1, it is necessary to increase the tolerance of the secondary pressure to be held, and there is a problem that it is not possible to cope with equipment that requires accuracy.

  The present invention has been made in view of the above-described problems, and an object thereof is to improve the accuracy of the secondary pressure (control pressure) held by the electromagnetic proportional control valve.

  A first invention is an electromagnetic proportional control valve, which is a sleeve accommodated in a housing hole of a housing, and a spool that is slidably provided in the sleeve and in which thrust by the pressure of the secondary pressure port acts in the axial direction And a solenoid that is provided on one end surface side of the housing and applies thrust to one end of the spool, and a biasing member that is provided on the other end surface side of the housing and applies biasing force against the thrust by the solenoid to the other end of the spool And an adjusting mechanism that is provided on the other end surface side of the housing and adjusts the urging force of the urging member against the spool, and the pressure of the secondary pressure port includes the thrust by the solenoid against the spool, the urging force by the urging member, and The regulator is controlled by adjusting the communication of the secondary pressure port to the primary pressure port and the tank port according to the balance of thrust by the pressure of the secondary pressure port. Has a support portion for holding the biasing member between the other end portion of the spool, by changing the position of the support unit, and adjusts the biasing force of the biasing member.

  In the first invention, the biasing force of the biasing member that biases the spool against the thrust of the solenoid can be adjusted.

  The second invention is characterized in that the primary pressure port and the tank port are provided on both ends of the spool in the housing, respectively, and the secondary pressure port is provided between the primary pressure port and the tank port.

  In the second invention, the housing is a direct proportional electromagnetic proportional control valve that increases the secondary pressure as the current supplied to the solenoid increases, and the secondary pressure decreases as the current supplied to the solenoid increases. Therefore, it is possible to cope with any of the inversely proportional electromagnetic proportional control valves, and the degree of freedom in designing the electromagnetic proportional control valve can be improved.

  According to the present invention, it is possible to improve the accuracy of the secondary pressure (control pressure) held by the electromagnetic proportional control valve.

FIG. 1 is a cross-sectional view of an electromagnetic proportional control valve. FIG. 2 is an enlarged cross-sectional view of the electromagnetic proportional control valve showing the spool, sleeve and housing of the first pressure reducing valve portion of the electromagnetic proportional control valve in an enlarged manner. FIG. 3 is a diagram illustrating the characteristics of the secondary pressure (control pressure) with respect to the control current of the inversely proportional second pressure reducing valve unit.

  With reference to FIGS. 1-3, the electromagnetic proportional control valve 100 which concerns on embodiment of this invention is demonstrated.

  The electromagnetic proportional control valve 100 controls the pressure output to the device to be controlled according to the control current supplied to the solenoid 7. The control pressure output from the electromagnetic proportional control valve 100 is supplied to the pressure chamber 112 of the device, and the operation of the device is controlled. Below, although the example which uses hydraulic oil as a working fluid is demonstrated, you may use other fluids, such as working water, as a working fluid.

  As shown in FIGS. 1 and 2, the electromagnetic proportional control valve 100 includes a primary pressure port 11 to which a primary pressure is supplied, a secondary pressure port 12 that outputs a secondary pressure as a control pressure to a control target, and a tank 113. A housing 1 having a tank port 13 to be connected, a sleeve 3 accommodated in the accommodation hole 2 of the housing 1, a spool 5 slidably provided in the sleeve 3, and one end face (lower end face in the figure) of the housing 1 A solenoid 7 that is provided on the 1a side and applies thrust Fs to one end portion (lower end portion in the figure) of the spool 5 and another end portion (upper end face in the figure) 1b side of the housing 1 And a spring 4 as a biasing member that applies a biasing force Fk against the thrust Fs by the solenoid 7 to the other end surface (upper end surface in the drawing) 1b side of the housing 1. Comprising an adjustment mechanism 9 including a bolt 8 as an adjustment member for adjusting the force Fk, the.

  The electromagnetic proportional control valve 100 according to the present embodiment is supplied to the solenoid 7 and the first pressure reducing valve portion 101 that constitutes a direct proportional control valve that increases the secondary pressure as the current supplied to the solenoid 7 increases. And a second pressure reducing valve portion 102 that constitutes an inverse proportional control valve that lowers the secondary pressure as the current increases. Each of the first pressure reducing valve portion 101 and the second pressure reducing valve portion 102 includes a sleeve 3, a spool 5, a solenoid 7, a spring 4, and an adjusting mechanism 9. The first pressure-reducing valve portion 101 and the second pressure-reducing valve portion 102 are partially different in shape of the sleeve 3, the spool 5, the bolt 8, and the like, but have the same configuration, and therefore have the same reference numerals. The configuration of each unit will be described.

  The solenoid 7 is attracted to a coil 71 that generates a magnetic force in accordance with a control current supplied from an external device, a fixed core 73 that is excited by the magnetic force of the coil 71, and a shaft that is attracted to the excited fixed core 73. A movable iron core (plunger) 72 that moves in the direction and a push rod 74 that is fixed to the movable iron core 72 and moves in the axial direction together with the movable iron core 72 are provided. In the case 76 of the solenoid 7, there is provided a stopper portion 75 with which one end of a push rod 74 penetrating the movable iron core 72 comes into contact.

  The primary pressure port 11 is supplied with a supply pressure from a hydraulic pump 111 as a fluid pressure supply source as a primary pressure. The secondary pressure port 12 outputs a secondary pressure as a control pressure to the pressure chamber 112 of the device to be controlled. The tank port 13 is connected to a tank 113 that stores hydraulic oil. The hydraulic oil stored in the tank 113 is sucked up by the hydraulic pump 111, supplied to the electromagnetic proportional control valve 100, and guided to the pressure chamber 112 of the device to be controlled through the electromagnetic proportional control valve 100.

  The primary pressure port 11 and the tank port 13 are provided on both ends of the spool 5 in the housing 1. In the present embodiment, the tank port 13 is provided on one end side (the lower end side in the drawing) of the spool 5, that is, the solenoid 7 side, and the primary pressure port 11 is the other end side (the upper end side in the drawing) of the spool 5, that is, the adjustment mechanism 9 side. Provided. The secondary pressure port 12 is provided between the primary pressure port 11 and the tank port 13.

  The sleeve 3 is a substantially cylindrical member, and includes a sliding hole 40 penetrating in the axial direction, and a first communication hole 31, a second communication hole 32, and a third communication hole 33 penetrating in the radial direction. The axial direction is the central axis direction of the sleeve 3 and the spool 5 that slides in the sleeve 3. The first communication hole 31 communicates the primary pressure port 11 and the inside of the sleeve 3, the second communication hole 32 communicates the secondary pressure port 12 and the inside of the sleeve 3, and the third communication hole 33 serves as the tank port 13 and the sleeve 3. 3 communicates with the inside.

  Each of the communication holes 31, 32, 33 extends from the other end side (the upper end side in the drawing) of the sleeve 3 to the one end side (the lower end side in the drawing), the first communication hole 31, the second communication hole 32, and the third communication hole 33. Are provided in this order. Each of the communication holes 31, 32, and 33 may be provided one by one, or a plurality may be provided along the circumferential direction as shown in the figure.

  The sliding hole 40 has a first sliding part 41, a second sliding part 42, a third sliding part 43, and a fourth sliding part 44. Each of the sliding portions 41, 42, 43, 44 has a circular opening whose cross section is centered on the central axis of the sleeve 3, and is provided corresponding to each of the land portions 51, 52, 53, 54 described later. . The sliding portions 41, 42, 43, 44 are respectively formed from the other end side (the upper end side in the drawing) of the sleeve 3 toward the one end side (the lower end side in the drawing), the first sliding portion 41, the second sliding portion 42, The third sliding portion 43 and the fourth sliding portion 44 are provided in this order. Each sliding part 41,42,43,44 is provided mutually spaced apart in the axial direction. Between each sliding part 41,42,43,44, it is set as the annular groove recessed in radial direction outward.

  The inner diameter of the first sliding portion 41 and the inner diameter of the second sliding portion 42 are the same, and the inner diameter of the third sliding portion 43 and the inner diameter of the fourth sliding portion 44 are the same. In the first pressure reducing valve portion 101, the inner diameter of the third sliding portion 43 is larger than the inner diameter of the second sliding portion 42. In the second pressure reducing valve portion 102, the inner diameter of the third sliding portion 43 is smaller than the inner diameter of the second sliding portion 42.

  A first communication hole 31 is provided in the annular groove between the first sliding portion 41 and the second sliding portion 42. A second communication hole 32 is provided in the annular groove between the second sliding portion 42 and the third sliding portion 43. A third communication hole 33 is provided in the annular groove between the third sliding portion 43 and the fourth sliding portion 44.

  The spool 5 is a shaft-like member whose one end (the lower end in the figure) is fixed to the push rod 74 of the solenoid 7. In the spool 5, the first land portion 51, the second land portion 52, the third land portion 53, and the fourth land portion 54 are directed from the other end side (the upper end side in the drawing) to the one end side (the lower end side in the drawing). Are provided in this order. Each land part 51, 52, 53, 54 protrudes radially outward. Each of the land portions 51, 52, 53, 54 has a circular cross section whose center is the central axis of the spool 5. The land portions 51, 52, 53, 54 are provided apart from each other in the axial direction. Between each land part 51,52,53,54, it is set as the annular groove dented to radial inside.

  The first land portion 51 slides along the first sliding portion 41 of the sleeve 3, and the second land portion 52 slides along the second sliding portion 42 of the sleeve 3. The third land portion 53 slides along the third sliding portion 43 of the sleeve 3, and the fourth land portion 54 slides along the fourth sliding portion 44 of the sleeve 3. The outer diameter of the first land portion 51 and the outer diameter of the second land portion 52 are the same, and the outer diameter of the third land portion 53 and the outer diameter of the fourth land portion 54 are the same. In the first pressure reducing valve portion 101, the outer diameter of the third land portion 53 is larger than the outer diameter of the second land portion 52. In the second pressure reducing valve portion 102, the outer diameter of the third land portion 53 is smaller than the outer diameter of the second land portion 52.

  The third land portion 53 of the first pressure reducing valve portion 101 constitutes a pressure receiving portion where the pressure (secondary pressure) of the secondary pressure port 12 acts in one axial direction (the direction of arrow A). One axial direction (the direction of arrow A) is a direction in which the spring 4 biases the spool 5 and is a direction against the thrust of the solenoid 7 (a direction from the other end surface 1b side of the housing 1 toward the one end surface 1a side). ). Similarly, the second land portion 52 of the second pressure reducing valve portion 102 constitutes a pressure receiving portion where the pressure (secondary pressure) of the secondary pressure port 12 acts in the other axial direction (direction of arrow B). The other axial direction (the direction of arrow B) is the direction of thrust of the solenoid 7 and the direction against the urging force of the spring 4 (the direction from the one end surface 1a side of the housing 1 toward the other end surface 1b side). .

  In the first pressure reducing valve portion 101, the pressure receiving area of the large-diameter third land portion 53 is larger than the pressure receiving area of the small-diameter second land portion 52. Therefore, the spool 5 of the first pressure reducing valve portion 101 has a thrust Fa due to the pressure (secondary pressure) of the secondary pressure port 12, that is, pressure received by the large-diameter third land portion 53 and the small-diameter second land portion 52. The area difference thrust Fa acts in one axial direction (the direction of arrow A). On the other hand, in the second pressure reducing valve portion 102, the pressure receiving area of the large-diameter second land portion 52 is larger than the pressure receiving area of the small-diameter third land portion 53. Therefore, the spool 5 of the second pressure reducing valve portion 102 has a thrust Fa due to the pressure (secondary pressure) of the secondary pressure port 12, that is, pressure received by the second land portion 52 having a large diameter and the third land portion 53 having a small diameter. The area difference thrust Fa acts in the other axial direction (the direction of arrow B).

  An opening of the fourth sliding portion 44 is provided on one end surface (the lower end surface in the drawing) of the sleeve 3. Between one end face (the lower end face in the figure) of the sleeve 3 and the fixed iron core 73 of the solenoid 7, a rod chamber 21 into which the push rod 74 enters and exits is defined. On the other end side (the upper end side in the figure) of the sleeve 3, a spring chamber 22 that houses the spring 4 is defined by the first land portion 51, the inner peripheral surface of the sliding hole 40, and the bolt 8 that constitutes the adjustment mechanism 9. Is done. The spring 4 is interposed between the bolt 8 and the first land portion 51 in a compressed state, and biases the spool 5 toward the solenoid 7 in one axial direction (direction of arrow A). For this reason, an elastic force corresponding to the elastic deformation amount (compression amount) of the spring 4 acts on the spool 5 in the axial direction as an urging force.

  A thrust Fs by the solenoid 7 acts on the spool 5 in the other axial direction (in the direction of arrow B), and a biasing force Fk by the spring 4 acts in one axial direction (in the direction of arrow A). Further, in the first pressure reducing valve portion 101, the thrust Fa due to the pressure (secondary pressure) of the secondary pressure port 12 acts on the spool 5 in one axial direction (direction of arrow A), and the second pressure reducing valve portion 102. Then, the thrust Fa due to the pressure (secondary pressure) of the secondary pressure port 12 acts on the spool 5 in the other axial direction (direction of arrow B).

  The first pressure reducing valve portion 101 and the second pressure reducing valve portion 102 are respectively connected to the primary pressure port 11 by the balance (balance) of the thrust Fs by the solenoid 7 with respect to the spool 5, the biasing force Fk by the spring 4 and the thrust Fa by the secondary pressure. By adjusting the communication of the secondary pressure port 12 to the tank port 13, the pressure of the secondary pressure port 12, that is, the secondary pressure (control pressure) output to the pressure chamber 112 is controlled.

  When no hydraulic oil is supplied to the electromagnetic proportional control valve 100 and no current flows through the solenoid 7, the spool 5 is placed in the initial position by the biasing force of the spring 4. The initial position of the spool 5 is a position where the push rod 74 is in contact with the stopper portion 75 in the case 76 of the solenoid 7. In the initial position, an initial load corresponding to the set length of the spring 4 acts on the spool 5.

  In the first pressure reducing valve portion 101, when the spool 5 is disposed at the initial position, the second land portion 52 is located in the second sliding portion 42, and the first communication hole 31 and the second communication hole 32 are in contact with each other. Block communication. At this time, in the first pressure reducing valve portion 101, the third land portion 53 is located outside the third sliding portion 43, and the second communication hole 32 and the third communication hole 33 communicate with each other. In the first pressure reducing valve portion 101, the second land portion 52 is located outside the second sliding portion 42 in a state where the spool 5 has moved upward in the figure by a predetermined amount from the initial position, and the first communication hole 31 and the second communication hole The hole 32 communicates. At this time, in the first pressure reducing valve portion 101, the third land portion 53 is located in the third sliding portion 43, and the communication between the second communication hole 32 and the third communication hole 33 is blocked.

  In the second pressure reducing valve portion 102, when the spool 5 is disposed at the initial position, the third land portion 53 is positioned in the third sliding portion 43, and the second communication hole 32 and the third communication hole 33 are connected to each other. Block communication. At this time, in the second pressure reducing valve portion 102, the second land portion 52 is located outside the second sliding portion 42, and the first communication hole 31 and the second communication hole 32 communicate with each other. In the second pressure reducing valve portion 102, the third land portion 53 is located outside the third sliding portion 43 in a state where the spool 5 has moved upward in the figure by a predetermined amount from the initial position, and the second communication hole 32 and the third communication hole are connected. The hole 33 communicates. At this time, in the second pressure reducing valve portion 102, the second land portion 52 is positioned in the second sliding portion 42 and blocks communication between the first communication hole 31 and the second communication hole 32.

  That is, the second land part 52 prohibits the flow of hydraulic oil from the primary pressure port 11 to the secondary pressure port 12 and the flow of hydraulic oil from the primary pressure port 11 to the secondary pressure port 12. Move between positions. The third land portion 53 has a position that allows the flow of hydraulic oil from the secondary pressure port 12 to the tank port 13, and a position that prohibits the flow of hydraulic oil from the secondary pressure port 12 to the tank port 13. Move between.

  The spool 5 is provided with a vertical hole 35 penetrating in the axial direction. The vertical hole 35 has one end side (lower end side in the figure) opened to the rod chamber 21 and the other end side (upper end side in the figure) opened to the spring chamber 22. Further, the vertical hole 35 is provided with a horizontal hole 36 penetrating in the radial direction. The horizontal hole 36 communicates the vertical hole 35 and the tank port 13 regardless of the amount of movement of the spool 5. For this reason, the spring chamber 22 and the rod chamber 21 are always in communication with the tank port 13.

  The operation of the first pressure reducing valve portion 101 of the electromagnetic proportional control valve 100 will be described.

  In a state where no current is supplied to the coil 71 of the solenoid 7, the spool 5 is urged in one axial direction (direction of arrow A) by the urging force of the spring 4, and is located at the initial position. In the initial position, the third land portion 53 is disposed between the third sliding portion 43 and the fourth sliding portion 44, and the second communication hole 32 and the third communication hole 33 communicate with each other. That is, the secondary pressure port 12 and the tank port 13 communicate with each other through the second communication hole 32 and the third communication hole 33. On the other hand, the second land portion 52 is disposed in the second sliding portion 42, and communication between the first communication hole 31 and the second communication hole 32 is blocked. That is, the communication between the primary pressure port 11 and the secondary pressure port 12 is blocked. Therefore, the pressure (secondary pressure) in the pressure chamber 112 connected to the secondary pressure port 12 is the tank pressure P0.

  When a control current is supplied to the coil 71 of the solenoid 7, the fixed iron core 73 is excited by the magnetic field generated around the coil 71, and the movable iron core 72 is drawn toward the fixed iron core 73 in the axial direction. The solenoid 7 gives a thrust Fs to the spool 5 via the push rod 74 by an electromagnetic force corresponding to the current value flowing through the coil 71. When the thrust Fs by the solenoid 7 with respect to the spool 5 exceeds the urging force Fk by the spring 4, the spool 5 moves in the other axial direction (direction of arrow B).

  Thereby, the second land portion 52 is disposed between the first sliding portion 41 and the second sliding portion 42, and the first communication hole 31 and the second communication hole 32 communicate with each other. That is, the primary pressure port 11 and the secondary pressure port 12 communicate with each other through the first communication hole 31 and the second communication hole 32. On the other hand, the third land portion 53 is disposed in the third sliding portion 43 and the communication between the second communication hole 32 and the third communication hole 33 is blocked. That is, the communication between the secondary pressure port 12 and the tank port 13 is blocked.

  Accordingly, the hydraulic oil supplied to the primary pressure port 11 is guided between the sleeve 3 and the spool 5 through the first communication hole 31, discharged from the secondary pressure port 12 through the second communication hole 32, and the pressure chamber 112. Led to. By supplying hydraulic oil to the pressure chamber 112, the pressure in the pressure chamber 112, that is, the secondary pressure rises.

  Due to the secondary pressure, the oil pressure corresponding to the difference in pressure receiving area between the third land portion 53 and the second land portion 52 acts on the spool 5 as a thrust Fa that presses the spool 5 in one axial direction (direction of arrow A). . While the sum of the thrust Fa due to the secondary pressure and the biasing force Fk due to the spring 4 is smaller than the thrust Fs due to the solenoid 7, the spool 5 moves in the other axial direction (the direction of arrow B). That is, the opening area between the primary pressure port 11 and the secondary pressure port 12 increases, and the secondary pressure increases.

  When the secondary pressure rises and the sum of the thrust Fa by the secondary pressure and the biasing force Fk by the spring 4 becomes larger than the thrust Fs by the solenoid 7, the spool 5 is pushed back in one axial direction (direction of arrow A). . As a result, the second land portion 52 returns into the second sliding portion 42, and the third land portion 53 returns between the third sliding portion 43 and the fourth sliding portion 44. Thereby, the communication between the primary pressure port 11 and the secondary pressure port 12 is cut off, and the secondary pressure port 12 and the tank port 13 are communicated again. Therefore, the hydraulic oil in the pressure chamber 112 is discharged to the tank 113 through the secondary pressure port 12 and the tank port 13, and the secondary pressure is reduced.

  The spool 5 repeats the operation of reciprocating in the sleeve 3 in the axial direction, and the flow of hydraulic oil into and out of the pressure chamber 112 is repeated. Therefore, the secondary pressure is controlled so that the thrust Fs by the solenoid 7 with respect to the spool 5 and the biasing force Fk by the spring 4 with respect to the spool 5 and the thrust Fa by the secondary pressure are balanced. That is, the amount of hydraulic oil leaked from the primary pressure port 11 to the secondary pressure port 12 and the amount of hydraulic oil leaked from the secondary pressure port 12 to the tank port 13 are balanced to maintain the secondary pressure.

  When the supply of the control current to the solenoid 7 is stopped, the solenoid 7 is demagnetized and the thrust Fs by the solenoid 7 is lost. For this reason, the spool 5 is moved in one axial direction (direction of arrow A) by the biasing force Fk of the spring 4 and the thrust Fa by the secondary pressure, and the initial position in a state where the push rod 74 is in contact with the stopper portion 75. Return to. At the initial position, the secondary pressure port 12 and the tank port 13 communicate with each other, so that the pressure (secondary pressure) in the pressure chamber 112 decreases to the tank pressure P0.

  The operation of the second pressure reducing valve portion 102 of the electromagnetic proportional control valve 100 will be described.

  In a state where no current is supplied to the coil 71 of the solenoid 7, the urging force Fk by the spring 4 acts on the spool 5 in one axial direction (the direction of the arrow A) and the thrust by the secondary pressure Fa acts toward the other side in the axial direction (the direction of arrow B). Therefore, the pressure (secondary pressure) in the pressure chamber 112 connected to the secondary pressure port 12 is the maximum pressure Pmax at which the thrust Fa due to the secondary pressure on the spool 5 and the biasing force Fk on the spool 5 are balanced.

  When a control current is supplied to the coil 71 of the solenoid 7, a thrust Fs generated by the solenoid 7 is generated. As a result, the sum of the thrust Fs by the solenoid 7 and the thrust Fa by the secondary pressure exceeds the biasing force Fk by the spring 4, and the spool 5 moves in the other axial direction (direction of arrow B).

  Accordingly, the third land portion 53 is disposed between the second sliding portion 42 and the third sliding portion 43, and the second communication hole 32 and the third communication hole 33 communicate with each other. That is, the secondary pressure port 12 and the tank port 13 communicate with each other through the second communication hole 32 and the third communication hole 33. On the other hand, the second land portion 52 is disposed in the second sliding portion 42 and the communication between the first communication hole 31 and the second communication hole 32 is blocked. That is, the communication between the primary pressure port 11 and the secondary pressure port 12 is blocked.

  Accordingly, the hydraulic oil from the pressure chamber 112 is guided between the sleeve 3 and the spool 5 through the second communication hole 32 and is discharged from the tank port 13 through the third communication hole 33. As the hydraulic oil in the pressure chamber 112 is discharged, the pressure in the pressure chamber 112, that is, the secondary pressure is reduced.

  While the sum of the thrust Fa by the secondary pressure and the thrust Fs by the solenoid 7 is larger than the urging force Fk by the spring 4, the spool 5 moves in the other axial direction (direction of arrow B). That is, the opening area between the secondary pressure port 12 and the tank port 13 increases, and the secondary pressure decreases.

  When the secondary pressure decreases and the sum of the thrust Fa due to the secondary pressure and the thrust Fs due to the solenoid becomes smaller than the biasing force Fk due to the spring 4, the spool 5 is pushed back in one axial direction (the direction of arrow A). Accordingly, the third land portion 53 is disposed in the third sliding portion 43, and the second land portion 52 is disposed between the second sliding portion 42 and the third sliding portion 43. Thereby, the communication between the secondary pressure port 12 and the tank port 13 is blocked, and the primary pressure port 11 and the secondary pressure port 12 are communicated. Therefore, the hydraulic oil guided from the hydraulic pump 111 through the primary pressure port 11 and the secondary pressure port 12 is supplied to the pressure chamber 112, and the secondary pressure rises.

  The spool 5 repeats the operation of reciprocating in the sleeve 3 in the axial direction, and the flow of hydraulic oil into and out of the pressure chamber 112 is repeated. For this reason, the secondary pressure is controlled so that the thrust Fs by the solenoid 7 against the spool 5 and the thrust Fa by the secondary pressure are balanced with the biasing force Fk by the spring 4 against the spool 5. That is, the amount of hydraulic oil leaked from the primary pressure port 11 to the secondary pressure port 12 and the amount of hydraulic oil leaked from the secondary pressure port 12 to the tank port 13 are balanced to maintain the secondary pressure.

  When the supply of the control current to the solenoid 7 is stopped, the solenoid 7 is demagnetized and the thrust Fs by the solenoid 7 is lost. For this reason, the secondary pressure is controlled so that the thrust Fa generated by the secondary pressure applied to the spool 5 and the biasing force Fk generated by the spring 4 applied to the spool 5 are balanced, and increases to the maximum pressure Pmax.

  As described above, in the first pressure reducing valve portion 101 and the second pressure reducing valve portion 102, the thrust Fs by the solenoid 7 is adjusted by the value of the control current supplied to the solenoid 7. That is, the secondary pressure (control pressure) output to the pressure chamber 112 is controlled by the value of the control current to the solenoid 7.

  Thus, the primary pressure port 11, the secondary pressure port 12, and the tank port 13 are provided along the axial direction in the accommodation holes 2 of the first pressure reducing valve portion 101 and the second pressure reducing valve portion 102, and the secondary pressure port A pressure port 12 is provided between the primary pressure port 11 and the tank port 13. Therefore, in either case of the directly proportional first pressure reducing valve portion 101 and the inversely proportional second pressure reducing valve portion 102, the primary pressure port 11 and the tank port according to the amount of movement of the spool 5 in the axial direction. Any one of the ports 13 can be communicated with the secondary pressure port 12, and the communication between the other port and the secondary pressure port 12 can be blocked. That is, each member (sleeve 3, spool 5, bolt 8, solenoid 7) constituting the first pressure reducing valve portion 101 and each member (sleeve 3) constituting the second pressure reducing valve portion 102 are accommodated in the housing hole 2 of the housing 1. Any of the spool 5, the bolt 8, and the solenoid 7) can be mounted.

  That is, the housing 1 according to this embodiment can be used as a housing of a direct proportional electromagnetic proportional control valve that increases the secondary pressure as the current supplied to the solenoid 7 increases, and is supplied to the solenoid 7. It can also be used as a housing for an inversely proportional electromagnetic proportional control valve that lowers the secondary pressure as the current increases. As described above, the housing 1 according to the present embodiment can cope with both a direct proportional electromagnetic proportional control valve and an inverse proportional electromagnetic proportional control valve. Can be improved. Each member (sleeve 3, spool 5, solenoid 7) to be incorporated into the accommodation hole 2 is a cartridge-type pressure reducing valve portion that can be assembled in advance, so that the accommodation hole 2 can be easily incorporated.

  The initial load of the spring 4 on the spool 5 is affected by variations in the set length of the spring 4 in addition to variations in manufacturing of the spring 4. Further, the pressure of the spring 4 applied to the spool 5 when the pressure output to the pressure chamber 112, that is, the secondary pressure corresponding to the control current is maintained, is influenced by the variation in the stroke amount of the spool 5 in addition to the above variation. receive.

  Therefore, in the present embodiment, an adjustment mechanism 9 that adjusts the urging force Fk of the spring 4 is provided on the other end surface (illustrated upper end surface) 1b side of the housing 1. As shown in FIG. 2, the adjustment mechanism 9 includes a bolt 8 as an adjustment member, a nut 90, a washer 95, and a spring receiving portion 84. The bolt 8 includes a first male screw portion 81 into which the female screw portion of the nut 90 is screwed, and a second male screw portion 82 that is provided on the inner periphery of the accommodation hole 2 and is screwed into the screw portion.

  On the other end surface 1 b of the housing 1, a step portion where the washer 95 is disposed is provided. The washer 95 is fixed to the housing 1 by being sandwiched between the step portion of the housing 1 and the nut 90. In a space defined by the washer 95, the receiving hole 2, and the bolt 8, a seal member 83 that seals between the bolt 8 and the receiving hole 2 is provided. That is, the bolt 8, the nut 90, the washer 95, and the seal member 83 function as a closing member that closes the opening of the accommodation hole 2.

  A spring receiving portion 84 as a support portion that holds the spring 4 between the other end portion (illustrated upper end portion) of the spool 5 is attached to one end portion (illustrated lower end portion) of the bolt 8. The spring receiving portion 84 includes a cylindrical tube portion 84a and an annular flange portion 84b extending radially outward from one end of the tube portion 84a. Since the amount of elastic deformation (the amount of compression from the natural length) of the spring 4 is determined according to the distance between the spring receiving portion 84 and the spool 5, the attachment of the spring 4 depends on the position of the spring receiving portion 84 in the axial direction. The force (spring load) changes. In the present embodiment, the bolt 8 is moved in the axial direction of the spool 5 to change the position of the spring receiving portion 84, thereby providing between the spring receiving portion 84 and the other end portion (the upper end portion in the drawing) of the spool 5. The biasing force Fk of the spring 4 to be adjusted is adjusted.

  The first male screw portion 81 is provided at the other end portion (the upper end portion in the drawing) of the bolt 8, and the second male screw portion 82 is provided between the first male screw portion 81 and the spring receiving portion 84. The other end portion (the upper end portion in the figure) of the bolt 8 is exposed from the housing hole 2 and can be operated from the outside of the housing 1. A hexagonal hole is provided on the other end surface (the upper end surface in the figure) of the bolt 8.

  In this embodiment, the amount of movement of the bolt 8 in the axial direction can be adjusted by inserting a tool such as a hexagonal bar wrench into the hexagon hole of the bolt 8 and rotating the bolt 8 with the nut 90 loosened. . For example, the bolt 8 can be moved in one axial direction (the direction of arrow A) by rotating the bolt 8 in one direction, and the bolt 8 can be moved in the other axial direction (the direction of arrow B) by rotating the bolt 8 in the other direction. ). Furthermore, the axial position of the bolt 8 can be fixed by rotating the nut 90 in one direction and tightening it on the washer 95 with a tool such as a spanner.

  A method for adjusting the biasing force Fk of the spring 4 will be described with reference to FIG.

  FIG. 3 is a diagram illustrating the characteristics of the secondary pressure (control pressure) with respect to the control current of the inverse proportional second pressure reducing valve unit 102, where the horizontal axis represents the control current supplied to the coil 71, and the vertical axis represents the secondary pressure. Pressure. In the figure, the target characteristic is indicated by a solid line, and the upper limit and the lower limit of the variation in secondary pressure with respect to the control current are indicated by a broken line. As described above, the upper limit and the lower limit are determined by manufacturing variations of the spring 4, variations in the set length of the spring 4, variations in the stroke amount of the spool 5, and variations in the attractive force characteristics of the solenoid 7.

  When the secondary pressure with respect to the control current is larger than the target characteristic, the urging force is adjusted in the direction to reduce the set load of the spring 4 by moving the bolt 8 in the other axial direction (the direction of arrow B). To do. On the other hand, when the secondary pressure with respect to the control current is small with respect to the target characteristic, the urging force is increased in the direction of increasing the set load of the spring 4 by moving the bolt 8 in one axial direction (direction of arrow A). Adjust.

  Thereby, the secondary pressure with respect to the control current can be brought close to a target characteristic. For example, when the target value of the secondary pressure when the control current is I1 is P1, and the entire measurement range is about several MPa, ± 5% F with respect to the target value (specification value) P1 . S. It becomes easy to fit within the range of (Full Scale). Therefore, according to the present embodiment, the accuracy of the secondary pressure held according to the control current can be improved.

  In particular, the spring 4 of the inverse proportional second pressure reducing valve portion 102 has a larger spring constant in terms of characteristics than the spring 4 of the first proportional pressure reducing valve portion 101. That is, the secondary pressure controlled by the inverse proportional type second pressure reducing valve unit 102 is affected by the variation of the biasing force Fk of the spring 4 as compared with the secondary pressure controlled by the directly proportional type first pressure reducing valve unit 101. growing. For this reason, the adjustment of the urging force Fk by the adjustment mechanism 9 greatly contributes particularly to the improvement of the accuracy of the secondary pressure by the inverse proportional second pressure reducing valve portion 102.

  When a spring for biasing the push rod 74 of the solenoid 7 and an adjusting mechanism for adjusting the biasing force of the spring are provided in place of the spring 4, the solenoid connector needs to be provided on the side of the case. In contrast, in the present embodiment, as shown in FIG. 1, the spring 4 and the adjusting mechanism 9 that adjusts the biasing force Fk of the spring 4 are provided on the other axial end side (upper end side in the drawing) of the spool 5. . Therefore, the connector 77 of the solenoid 7 can be provided at the end of the case 76 in the axial direction. In the present embodiment, the connector 77 of the solenoid 7 can be provided on either the side portion or the axial end portion of the case 76, and the degree of freedom of arrangement of the connector 77 is high.

  In the electromagnetic valve device described in Patent Document 1, a spring for urging the spool is provided in a spring accommodating hole provided in an end portion on the solenoid side of the sleeve. For this reason, in the electromagnetic valve device described in Patent Document 1, in order to reduce the variation in the control pressure with respect to the control current, for example, a spring for urging the push rod of the solenoid is newly added, and this new addition is added. An adjustment mechanism for adjusting the biasing force of the spring is provided. In this case, it is necessary to newly add a spring, the number of parts increases, and the manufacturing cost increases. On the other hand, in the present embodiment, the adjustment mechanism 9 can adjust the set length of the spring 4 that generates the biasing force Fk that resists the thrust Fs of the solenoid 7. There is no need to add a new one, and an increase in manufacturing cost due to the addition of the spring can be prevented.

  According to embodiment mentioned above, there exists the following effect.

  The pressure of the secondary pressure port 12 (secondary pressure) is determined by the balance of the thrust Fs by the solenoid 7 with respect to the spool 5, the biasing force Fk by the spring 4, and the thrust Fa by the pressure (secondary pressure) of the secondary pressure port 12. It is controlled by adjusting the communication of the secondary pressure port 12 to the pressure port 11 and the tank port 13. The adjusting mechanism 9 is provided on the surface (the other end surface 1 b) of the housing 1 opposite to the mounting surface of the solenoid 7. A spring receiving portion 84 that clamps the spring 4 with the spool 5 is attached to the tip of the bolt 8 constituting the adjusting mechanism 9, and the biasing force of the spring 4 is changed by changing the position of the spring receiving portion 84. Adjust Fk. The adjustment mechanism 9 can adjust the urging force Fk of the spring 4 that urges the spool 5 against the thrust Fs of the solenoid 7, and can perform adjustment including variations in the attraction force of the solenoid 7. The accuracy of the secondary pressure held by the control valve 100 can be improved.

  The housing 1 is a direct proportional electromagnetic proportional control valve that increases the secondary pressure as the current supplied to the solenoid 7 increases, and the inverse proportionality that decreases the secondary pressure as the current supplied to the solenoid 7 increases. Since any type of electromagnetic proportional control valve can be used, the degree of freedom in designing the electromagnetic proportional control valve 100 can be improved.

  As described above, in this embodiment, the cartridge type pressure reducing valve portion assembled to the housing 1 can be either a direct proportional type or an inverse proportional type, and by adjusting the biasing force Fk of the spring 4, In both cases, the characteristics can be set with high accuracy.

  The following modifications are also within the scope of the present invention, and it is possible to combine the structure shown in the modification and the structure described in the above embodiment, or to combine the structures described in the following different modifications. It is.

<Modification 1>
The adjustment mechanism 9 is not limited to the one described in the above embodiment, and various forms that can adjust the urging force Fk of the spring 4 by an external operation can be adopted. For example, in the above-described embodiment, the example in which the spring receiving portion 84 is attached to the tip end portion of the bolt 8 has been described. However, the spring 4 may be in direct contact with the tip end portion of the bolt 8, that is, the bolt 8 and the spring receiving portion. 84 may be integrally formed. In this case, the front end portion of the bolt 8 functions as a support portion that holds the spring 4 between the end portion of the spool 5.

<Modification 2>
In the above embodiment, the example in which the ports are provided in the order of the tank port 13, the secondary pressure port 12, and the primary pressure port 11 from the one end surface 1a side to the other end surface 1b side of the housing 1 has been described. Is not limited to this. For example, you may provide each port in order of the primary pressure port 11, the secondary pressure port 12, and the tank port 13 toward the other end surface 1b side from the one end surface 1a side of the housing 1. FIG.

<Modification 3>
In the above embodiment, the example in which the housing 1 is provided with the first proportional-type first pressure reducing valve portion 101 and the inversely proportional second pressure-reducing valve portion 102 one by one has been described, but the present invention is not limited to this. The housing 1 may be provided with two directly proportional first pressure reducing valve portions 101 or two inversely proportional second pressure reducing valve portions 102. In any case, the configuration of the housing 1 is the same as that in the above embodiment.

<Modification 4>
The number of pressure reducing valve portions 101 and 102 provided in the housing 1 may be one, or may be three or more.

<Modification 5>
The bolt 8 of the first pressure-reducing valve portion 101 is replaced with the bolt of the second pressure-reducing valve portion 102 by reducing the inner diameters of the cylindrical portion 84a and the flange portion 84b of the spring receiving portion 84 of the second pressure-reducing valve portion 102 shown in FIG. 8 can also be used.

  The configuration, operation, and effect of the embodiment of the present invention configured as described above will be described together.

  The electromagnetic proportional control valve 100 includes a housing 1 having a primary pressure port 11, a secondary pressure port 12, and a tank port 13, a sleeve 3 accommodated in the accommodation hole 2 of the housing 1, and a slidable arrangement within the sleeve 3. A spool 5 in which a thrust Fa due to the pressure of the secondary pressure port 12 acts in the axial direction, a solenoid 7 provided on one end face 1a side of the housing 1 and applying a thrust Fs to one end of the spool 5, and a housing 1 A spring 4 is provided on the other end surface 1b side, provided on the other end surface 1b side of the housing 1, and a spring 4 as an urging member for applying an urging force Fk against the thrust Fs by the solenoid 7 to the other end portion of the spool 5. And an adjustment mechanism 9 that adjusts the biasing force Fk of the spring 4 against the pressure of the secondary pressure port 12 is controlled by the thrust Fs of the solenoid 7 against the spool 5 and the spring 4. The adjustment mechanism 9 is controlled by adjusting the communication of the secondary pressure port 12 with respect to the primary pressure port 11 and the tank port 13 according to the balance of the thrust Fa due to the biasing force Fk and the pressure of the secondary pressure port 12. A spring receiving portion 84 is provided as a support portion for sandwiching the spring 4 with the other end portion, and the biasing force of the spring 4 is adjusted by changing the position of the spring receiving portion 84.

  In this configuration, the biasing force of the spring 4 that biases the spool 5 against the thrust of the solenoid 7 can be adjusted. As a result, the accuracy of the secondary pressure (control pressure) held by the electromagnetic proportional control valve 100 can be improved.

  In the electromagnetic proportional control valve 100, a primary pressure port 11 and a tank port 13 are provided on both ends of the spool 5 in the housing 1, and a secondary pressure port 12 is provided between the primary pressure port 11 and the tank port 13. It is provided.

  In this configuration, the housing 1 increases the secondary pressure as the current supplied to the solenoid 7 increases, and the secondary pressure increases as the current supplied to the solenoid 7 increases. Any of the inversely proportional electromagnetic proportional control valves to be reduced can be accommodated, and the degree of freedom in designing the electromagnetic proportional control valve 100 can be improved.

  As mentioned above, although embodiment of this invention was described, the said embodiment only showed a part of application example of this invention, and the meaning which limits the technical scope of this invention to the specific structure of the said embodiment. Absent.

  DESCRIPTION OF SYMBOLS 1 ... Housing, 1a ... One end surface, 1b ... Other end surface, 2 ... Accommodating hole, 3 ... Sleeve, 4 ... Spring (biasing member), 5 ... Spool, 7 ... Solenoid, 8 ... Bolt (adjusting member), 9 ... Adjustment mechanism, 11 ... Primary pressure port, 12 ... Secondary pressure port, 13 ... Tank port, 84 ... Spring receiving part (supporting part), 100 ... Proportional control valve, Fa ... Thrust by secondary pressure, Fk ... Biasing force, Fs ... Thrust by solenoid

Claims (2)

An electromagnetic proportional control valve,
A housing having a primary pressure port, a secondary pressure port and a tank port;
A sleeve received in the receiving hole of the housing;
A spool that is slidably provided in the sleeve and in which a thrust generated by the pressure of the secondary pressure port acts in an axial direction;
A solenoid that is provided on one end surface side of the housing and applies thrust to one end of the spool;
An urging member that is provided on the other end surface side of the housing and applies an urging force against the thrust by the solenoid to the other end of the spool;
An adjustment mechanism that is provided on the other end surface side of the housing and adjusts the urging force of the urging member with respect to the spool;
The pressure of the secondary pressure port is determined by the balance of the thrust by the solenoid, the biasing force by the biasing member, and the thrust by the pressure of the secondary pressure port with respect to the spool, and the secondary pressure with respect to the primary pressure port and the tank port. Controlled by adjusting the communication of the pressure port,
The adjustment mechanism has a support portion that holds the biasing member between the other end portion of the spool, and adjusts the biasing force of the biasing member by changing the position of the support portion. Proportional electromagnetic control valve. The electromagnetic proportional control valve according to claim 1,
The primary pressure port and the tank port are provided on both end sides of the spool in the housing,
The electromagnetic pressure control valve, wherein the secondary pressure port is provided between the primary pressure port and the tank port.

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