JP6715272B2 - Solenoid plunger position detector - Google Patents

Description

The present invention relates to a solenoid plunger position detection device.

The solenoid includes a coil, a plunger that moves by exciting the coil, a fixed iron core having an attraction surface that attracts the plunger, and a plunger spring that biases the plunger in a direction in which the plunger is separated from the attraction surface of the fixed iron core. have. Further, for example, in Patent Document 1, the inductance generated by exciting the coil is monitored, and the position of the plunger is detected based on the change in the inductance.

JP, 2008-304041, A

However, as in Patent Document 1, in order to detect the inductance of the coil in the state where the drive current is supplied to the coil, a complicated circuit configuration is required, which causes a problem in detection accuracy and cost. Further, in order to detect the position of the plunger while the supply of the drive current to the coil is stopped, it is necessary to supply the pulse current to the coil. As a result, the magnetomotive force of the coil becomes small, and the movement of the plunger due to the excitation of the coil may become unstable.

The present invention has been made to solve the above problems, and an object thereof is to make it possible to improve detection accuracy and to provide an inexpensive structure. Furthermore, the movement of the plunger is unstable. Another object of the present invention is to provide a solenoid plunger position detection device capable of detecting the position of the plunger while avoiding

A solenoid plunger position detection device for solving the above-mentioned problems includes a coil, a plunger that moves by excitation of the coil, a fixed iron core having a suction surface that attracts the plunger, and the plunger that is separated from the suction surface. A plunger spring for urging the plunger in a direction to move, and a solenoid plunger position detecting device electrically connected to the plunger via the plunger spring in a state of being insulated from the fixed iron core. The conductive detection frame, the detection terminal electrically connected to the fixed core in a state of being insulated from the detection frame, and the capacitance generated between the plunger and the suction surface are detected by the detection unit. And a position detector that detects the position of the plunger based on the change in the capacitance, which is measured between the frame and the detection terminal.

In the plunger position detecting device of the solenoid, the solenoid contacts the fixed iron core in a state of penetrating a magnet that holds the plunger in a state of being attracted to the attraction surface, and excites the coil to cause the magnet to move to the fixed iron core. It is preferable to have a magnetic circuit forming component that cooperates to form a magnetic circuit, and the detection terminal is electrically connected to the fixed iron core via the magnetic circuit forming component.

In the solenoid plunger position detection device, the detection frame may be molded with a resin material, and a sealing material may be provided between the detection frame and the resin material.

In the solenoid plunger position detection device, the position detection unit is a microcomputer mounted on a control board that controls energization to the coil, and the detection frame and the detection terminal are electrically connected to the control board. It is good to be connected.

According to the present invention, the detection accuracy can be made good, and the structure is inexpensive, and further, the position of the plunger can be detected while avoiding the unstable movement of the plunger. it can.

Sectional drawing of the self-holding type solenoid valve in embodiment. Sectional drawing which expanded a part of self-holding type solenoid valve. Sectional drawing which shows a magnetic circuit. Sectional drawing which shows a magnetic circuit. Sectional drawing of a self-holding type solenoid valve. Sectional drawing which expanded a part of self-holding type solenoid valve.

Hereinafter, an embodiment in which a solenoid plunger position detecting device is embodied will be described with reference to FIGS. The solenoid plunger position detection device of the present embodiment detects the position of the solenoid plunger used in the self-holding solenoid valve.

As shown in FIG. 1, the body 11 of the self-holding solenoid valve 10 includes a valve body 12 having a rectangular block shape, a connecting block 13 connected to one end side in the longitudinal direction of the valve body 12, and a connecting block 13. A magnetic cover 14 having a bottomed long rectangular tube shape and connected to the side opposite to the valve body 12 is provided. The valve body 12, the connection block 13, and the magnetic cover 14 are made of, for example, a synthetic resin material. Therefore, the valve body 12, the connection block 13, and the magnetic cover 14 are made of a non-magnetic material.

As shown in FIG. 2, the valve body 12 is formed with a circular hole-shaped valve hole 16 that accommodates the spool valve 15 so as to be capable of reciprocating. A supply port 17, an output port 18, and a discharge port 19 are formed in the valve body 12. The supply port 17, the output port 18, and the discharge port 19 are respectively formed in the valve body 12 so as to communicate with the valve hole 16 and to be arranged in this order in the axial direction of the spool valve 15. In the axial direction of the spool valve 15, the discharge port 19 is located closer to the connecting block 13 side than the output port 18, and the supply port 17 is located farther from the connecting port 13 than the output port 18. .. The self-holding solenoid valve 10 of this embodiment is a 3-port solenoid valve.

The valve hole 16 has a first hole 16a, a second hole 16b, a third hole 16c, and a fourth hole 16d having different hole diameters. The first hole 16a, the second hole 16b, the third hole 16c, and the fourth hole 16d are arranged in this order from the end surface of the valve body 12 on the side opposite to the connecting block 13 toward the connecting block 13 and the spool. Each extends in the axial direction of the valve 15. The second hole 16b has a smaller hole diameter than the first hole 16a. The diameter of the third hole 16c is smaller than that of the second hole 16b. The fourth hole 16d has a larger hole diameter than the second hole 16b and the third hole 16c and a smaller hole diameter than the first hole 16a.

The first hole 16a and the second hole 16b are connected by an annular first step surface 16e extending in a direction orthogonal to the axial direction of the spool valve 15. The second hole 16b and the third hole 16c are connected by an annular second step surface 16f extending in a direction orthogonal to the axial direction of the spool valve 15. The third hole 16c and the fourth hole 16d are connected by an annular third step surface 16g extending in a direction orthogonal to the axial direction of the spool valve 15. The first hole 16 a communicates with the supply port 17 and the output port 18. The second hole 16b communicates with the discharge port 19. The end of the first hole 16a on the opposite side of the second hole 16b is a female screw hole 16h.

The valve body 12 is provided with a bottomed cylindrical plug 20 that closes the end of the valve hole 16 on the opposite side of the connection block 13. The plug 20 has a disc-shaped bottom portion 20a and a cylindrical extension portion 20b extending from the peripheral edge portion of the bottom portion 20a along the inner peripheral surface of the valve hole 16. A male screw 20c screwed into the female screw hole 16h is formed on the outer peripheral surface of the bottom portion 20a. The plug 20 is attached to the valve hole 16 of the valve body 12 by screwing the male screw 20c of the bottom portion 20a into the female screw hole 16h, and the bottom portion 20a is an end portion of the valve hole 16 opposite to the connecting block 13. Is blocked.

A mounting hole 20d is formed in the bottom portion 20a. The mounting hole 20d penetrates the bottom portion 20a in the axial direction of the spool valve 15. The suction manual shaft 21 is attached to the mounting hole 20d. The suction manual shaft 21 is mounted in the mounting hole 20d by being inserted into the mounting hole 20d from the inside of the extending portion 20b. The suction manual shaft 21 has an annular flange portion 21a that abuts around the mounting hole 20d on the inner surface of the bottom portion 20a. The flange portion 21a is prevented from coming off the valve body 12 from the mounting hole 20d by contacting the inner surface of the bottom portion 20a.

The extending portion 20b passes through the periphery of the opening of the supply port 17 to the first hole 16a and extends to the periphery of the opening of the output port 18 to the first hole 16a. The inside of the extending portion 20b communicates with the first hole 16a. A communication hole 20e is formed in a portion of the extending portion 20b facing the supply port 17.

On the outer peripheral surface of the extending portion 20b, a first annular shape that seals between a portion of the inner peripheral surface of the first hole 16a between the supply port 17 and the output port 18 and the outer peripheral surface of the extending portion 20b. The seal member 22a is attached. The first sealing member 22a allows the supply port 17 and the output port to be interposed between the portion of the inner peripheral surface of the first hole 16a between the supply port 17 and the output port 18 and the outer peripheral surface of the extending portion 20b. Leakage of fluid between 18 is regulated.

Further, on the outer peripheral surface of the extending portion 20b, a circle that seals between the outer peripheral surface of the extending portion 20b and a portion of the inner peripheral surface of the first hole 16a opposite to the output port 18 with respect to the supply port 17. An annular second seal member 22b is attached. Then, by the second seal member 22b, from the supply port 17 through the portion of the inner peripheral surface of the first hole 16a opposite to the output port 18 from the supply port 17 and the outer peripheral surface of the extending portion 20b. The leakage of fluid is regulated.

The tip end surface of the extending portion 20b faces the first step surface 16e in the axial direction of the spool valve 15. An annular first valve seat 23 is projectingly provided on the tip surface of the extending portion 20b. An annular second valve seat 24 is projectingly provided on the first step surface 16e. The second valve seat 24 extends toward the first valve seat 23, and the first valve seat 23 and the second valve seat 24 face each other in the axial direction of the spool valve 15. Between the first valve seat 23 and the second valve seat 24 in the first hole 16a is a valve chamber 25 that accommodates the valve element 15v mounted on the outer peripheral surface of the spool valve 15.

The spool valve 15 has a cylindrical shaft portion 15a and an annular large diameter portion 15b protruding from the outer peripheral surface of the shaft portion 15a. The shaft portion 15a passes through the third hole 16c and the second hole 16b from the fourth hole 16d, projects into the first hole 16a, and enters the extending portion 20b of the plug 20. The outer diameter of the shaft portion 15a is the same as the hole diameter of the third hole 16c. The inner peripheral surface of the third hole 16c is in sliding contact with the outer peripheral surface of the shaft portion 15a when the spool valve 15 moves in the axial direction, and functions as a guide surface that guides the axial movement of the spool valve 15.

The valve body 15v is made of rubber and has an annular shape, and is attached to the large diameter portion 15b so as to cover the outer peripheral surface of the large diameter portion 15b. The valve body 15v is arranged between the first valve seat 23 and the second valve seat 24 in the axial direction of the spool valve 15. The valve body 15v can be brought into and out of contact with the first valve seat 23 and the second valve seat 24.

A shaft member 26 is attached to the end surface of the shaft portion 15a on the plug 20 side. The shaft member 26 is arranged in the extending portion 20b of the plug 20. The shaft member 26 has a press-fitting portion 26a, a large-diameter portion 26b having a diameter larger than the outer diameter of the press-fitting portion 26a, and a shaft portion 26c continuous to the large-diameter portion 26b on the opposite side to the press-fitting portion 26a. doing. The shaft member 26 is attached to the shaft portion 15a by the press-fitting portion 26a being press-fitted into the press-fitting hole 15c formed in the end surface of the shaft portion 15a on the plug 20 side, and moves integrally with the spool valve 15. It is possible. The outer diameter of the large diameter portion 26b is substantially the same as the inner diameter of the extending portion 20b. An end surface of the shaft portion 26c on the side opposite to the large diameter portion 26b faces the suction manual shaft 21.

In the extending portion 20b, a spring accommodating chamber 27 is formed between the large diameter portion 26b and the bottom portion 20a of the plug 20. A valve body spring 28 is housed in the spring housing chamber 27. The valve body spring 28 is interposed between the large diameter portion 26b and the suction manual shaft 21. The valve body spring 28 biases the shaft member 26 and the spool valve 15 in a direction in which the valve body 15v separates from the first valve seat 23.

A packing 29 is attached to the outer peripheral surface of the large diameter portion 26b. The packing 29 is located closer to the bottom portion 20a of the plug 20 than the communication hole 20e of the plug 20 is. The packing 29 regulates the leakage of fluid from the supply port 17 to the spring accommodating chamber 27 via the outer peripheral surface of the large diameter portion 26b and the inner peripheral surface of the extending portion 20b.

As shown in FIG. 1, the connection block 13 is formed with a through hole 13 a communicating with the valve hole 16. The axis of the through hole 13a coincides with the axis of the valve hole 16. The magnetic cover 14 also has a bottom wall 14a and a peripheral wall 14b extending from the peripheral edge of the bottom wall 14a. The axis of the peripheral wall 14b coincides with the axis of the through hole 13a and the axis of the valve hole 16. An insertion hole 14c is formed in the bottom wall 14a. The axis of the insertion hole 14c coincides with the axis of the peripheral wall 14b.

A magnetic frame 30 made of a magnetic material is embedded in the magnetic cover 14. The magnetic frame 30 includes a plate-shaped bottom portion 30a that extends along the inner surface of the bottom wall 14a of the magnetic cover 14, and a cylindrical extension portion 30b that extends from the peripheral portion of the bottom portion 30a along the peripheral wall 14b of the magnetic cover 14. have. The magnetic frame 30 is integrated with the magnetic cover 14 by embedding the extending portion 30b in the peripheral wall 14b of the magnetic cover 14. The tip side portion of the inner peripheral surface of the extending portion 30b is exposed from the inner peripheral surface of the peripheral wall 14b of the magnetic cover 14. A female screw hole 30c is formed in the bottom portion 30a. The female screw hole 30c is located inside the insertion hole 14c. The axial center of the female screw hole 30c coincides with the axial center of the insertion hole 14c.

The self-holding solenoid valve 10 includes a solenoid 31. The solenoid 31 has a coil 32, a fixed iron core 33, a plunger 34, and a plunger spring 35. The fixed iron core 33 and the plunger 34 are made of magnetic material. A cylindrical bobbin 36 around which the coil 32 is wound is housed in the magnetic cover 14. The axis of the bobbin 36 coincides with the axis of the peripheral wall 14b of the magnetic cover 14.

The fixed iron core 33 is housed in the magnetic cover 14. The fixed iron core 33 has a shaft portion 33a and an annular flange portion 33b protruding from the end of the shaft portion 33a in a direction orthogonal to the axial direction of the shaft portion 33a. The shaft portion 33 a is inserted into the bobbin 36 from the bottom wall 14 a side of the magnetic cover 14. The axial length of the shaft portion 33a is shorter than the axial length of the bobbin 36. An end surface 33e of the shaft portion 33a opposite to the flange portion 33b has a flat surface shape. The flange portion 33b is in contact with the surface of the bobbin 36 on the side of the bottom wall 14a of the magnetic cover 14.

The plunger 34 has a columnar shape that protrudes from the inside of the bobbin 36 into the valve hole 16 of the valve body 12 through the through hole 13 a of the connecting block 13. The plunger 34 is located closer to the valve body 12 than the fixed iron core 33. The axis of the plunger 34 coincides with the axis of the shaft portion 33a of the fixed iron core 33. The end surface 34a of the plunger 34 on the side of the fixed iron core 33 is flat. The area of the end surface 34a of the plunger 34 is the same as the area of the end surface 33e of the shaft portion 33a of the fixed iron core 33. The end surface 34a of the plunger 34 can come into surface contact with the end surface 33e of the shaft portion 33a of the fixed iron core 33. An end surface 34b of the plunger 34 opposite to the fixed iron core 33 can be brought into contact with or separated from the spool valve 15.

An annular collar portion 34c projects from the outer peripheral surface of the plunger 34. The collar portion 34 c is located inside the through hole 13 a of the connection block 13. Further, a manual shaft recess 34d is formed on the outer peripheral surface of the plunger 34. The manual shaft recess 34d is continuous with the flange 34c and is located closer to the end surface 34b of the plunger 34 than the flange 34c.

A housing member 37 having a bottomed tubular shape is housed in the magnetic cover 14. The housing member 37 is arranged between the bobbin 36 and the bottom portion 30 a of the magnetic frame 30 in the axial direction of the plunger 34. The accommodating member 37 has a plate-shaped bottom portion 37a and a cylindrical extension portion 37b extending from the peripheral edge portion of the bottom portion 37a along the inner peripheral surface of the peripheral wall 14b of the magnetic cover 14. An insertion hole 37c is formed in the bottom portion 37a. The axial center of the insertion hole 37c coincides with the axial center of the female screw hole 30c of the magnetic frame 30.

The flange portion 33 b of the fixed iron core 33 is located inside the housing member 37. The outer peripheral surface of the flange portion 33b is in contact with the inner peripheral surface of the extending portion 37b of the housing member 37. A cylindrical magnet 38 is housed inside the housing member 37. The magnet 38 is arranged between the fixed iron core 33 and the bottom portion 37 a of the housing member 37 in the axial direction of the plunger 34. The outer peripheral surface of the magnet 38 is in contact with the inner peripheral surface of the extending portion 37b of the housing member 37.

The first magnetic core 39 is screwed into the female screw hole 30c of the magnetic frame 30. The first magnetic core 39 has a screw portion 39b having an external thread 39a formed on the outer peripheral surface thereof, and a columnar insertion portion 39c protruding from the screw portion 39b and inserted into the insertion hole 37c of the housing member 37 and the inside of the magnet 38. And have. An end surface of the insertion portion 39c on the side opposite to the screw portion 39b is in contact with the fixed iron core 33. Therefore, the insertion portion 39c of the first magnetic core 39 is in contact with the fixed iron core 33 while penetrating the magnet 38. The outer peripheral surface of the insertion portion 39c is in contact with the inner peripheral surface of the insertion hole 37c and the inner peripheral surface of the magnet 38.

As shown in FIGS. 3 and 4, in the self-holding solenoid valve 10, the magnetic flux of the magnet 38 is generated as indicated by the solid arrow. The magnetic flux of the magnet 38 passes through the magnet 38, the collar portion 34c of the fixed iron core 33, the extending portion 37b of the housing member 37, the bottom portion 37a of the housing member 37, and the magnet 38 in this order.

As shown in FIG. 1, a cylindrical second magnetic core 40 is arranged inside the tip end side of the magnetic frame 30. The second magnetic core 40 is located closer to the coupling block 13 than the bobbin 36 in the axial direction of the plunger 34. The outer peripheral surface of the second magnetic core 40 is in contact with the tip side portion of the inner peripheral surface of the extending portion 30b of the magnetic frame 30. The plunger 34 passes inside the second magnetic core 40.

As shown in FIG. 2, a manual shaft accommodating hole 42 is formed in the connecting block 13. The manual shaft accommodating hole 42 extends in a direction orthogonal to the axial direction of the plunger 34 and communicates with the through hole 13a. A columnar manual shaft 43 for separation is housed in the manual shaft housing hole 42. The detaching manual shaft 43 can reciprocate in the manual shaft accommodating hole 42. Further, the tip end portion of the detaching manual shaft 43 is capable of projecting and retracting with respect to the manual shaft housing hole 42. An inclined surface 43a is formed at the tip of the detaching manual shaft 43. The inclined surface 43a is formed on the valve body 12 side at the distal end portion of the disengagement manual shaft 43. The inclined surface 43a can be slidably contacted with the corner portion 34e of the manual shaft recess 34d on the valve body 12 side when the tip of the manual shaft 43 for detachment projects from the manual shaft accommodation hole 42. The corner portion 34e has a tapered shape.

A return spring 44 is housed in the manual shaft housing hole 42. The return spring 44 urges the detaching manual shaft 43 in a direction in which the tip of the detaching manual shaft 43 is retracted into the manual shaft accommodating hole 42. Further, the disengagement manual shaft 43 is formed with an insertion hole 43h penetrating in a direction orthogonal to the moving direction of the disengagement manual shaft 43. A columnar insertion member 45 supported by the connection block 13 is inserted into the insertion hole 43h. In the moving direction of the detaching manual shaft 43, there is a relatively large gap between the insertion member 45 and the inner peripheral surface of the insertion hole 43h. The detaching manual shaft 43 is movable in the manual shaft accommodating hole 42 by the amount of the gap between the insertion member 45 and the inner peripheral surface of the insertion hole 43h. The movement of the separation manual shaft 43 due to the urging force of the return spring 44 is restricted by the inner peripheral surface of the insertion hole 43h contacting the insertion member 45, and the separation manual shaft 43 pops out from the manual shaft accommodation hole 42. It is supposed to not.

As shown in FIGS. 3 and 4, an annular flange portion 13f projects from the end portion of the inner peripheral surface of the through hole 13a of the coupling block 13 on the second magnetic core 40 side. Further, a conductive detection frame 46 is embedded in the connection block 13. The detection frame 46 is molded by the connection block 13 which is a resin material. The detection frame 46 includes a plate-shaped main body portion 46a having an insertion hole 46h into which the plunger 34 is inserted, and a columnar terminal portion 46b extending from the main body portion 46a in a direction orthogonal to the axial direction of the plunger 34. ,have. The periphery of the insertion hole 46h on the end surface of the main body portion 46a on the second magnetic core 40 side extends along the flange portion 13f. The periphery of the insertion hole 46h on the end surface of the main body portion 46a on the side opposite to the second magnetic core 40 side projects from the inner peripheral surface of the through hole 13a of the coupling block 13 and is exposed from the coupling block 13.

As shown in FIG. 1, the plunger spring 35 is interposed between an end surface of the main body portion 46a on the side opposite to the second magnetic core 40 side and the flange portion 34c of the plunger 34. One end of the plunger spring 35 is supported by the end surface of the main body portion 46a opposite to the second magnetic core 40 side, and the other end of the plunger spring 35 is supported by the flange portion 34c of the plunger 34. The plunger spring 35 urges the plunger 34 in a direction in which the end surface 34 a of the plunger 34 is separated from the end surface 33 e of the shaft portion 33 a of the fixed iron core 33. The urging force of the plunger spring 35 is larger than the urging force of the valve body spring 28.

The self-holding solenoid valve 10 includes a control board 50 that controls energization of the coil 32. A microcomputer 51 is mounted on the control board 50. The coil 32 is electrically connected to the control board 50 via the coil terminal 32a. Further, the self-holding solenoid valve 10 includes a power feeding section 52. A power supply (not shown) is connected to the power supply unit 52.

Then, when an input voltage is applied to the control board 50 from the power supply via the power supply section 52, the energization of the control board 50 to the coil 32 is started. The microcomputer 51 controls the drive of the control board 50 so that the direction of the current supplied to the coil 32 is the forward direction or the reverse direction.

As shown in FIG. 3, for example, when the direction of the current supplied to the coil 32 is the forward direction, the fixed iron core 33→the plunger 34→the second magnetic core 40→the magnetic frame, as indicated by the two-dot chain line arrow. A magnetic circuit through which magnetic flux passes is formed in the order of 30→first magnetic core 39→fixed iron core 33. The magnetic flux of the magnetic circuit passes through in the same direction as the magnetic flux of the magnet 38 passes through. The magnetic circuit is formed by exciting the coil 32. Therefore, the solenoid 31 has a magnetic frame 30, a first magnetic core 39, and a second magnetic core 40, which are magnetic circuit forming components that cooperate with the fixed iron core 33 to form a magnetic circuit by excitation of the coil 32. There is.

Then, the magnetomotive force of the coil 32 works in a direction in which the plunger 34 is attracted toward the fixed iron core 33, and the magnetomotive force of the coil 32 and the attraction force of the magnet 38 resist the biasing force of the plunger spring 35 and the plunger 34. The plunger 34 moves in a direction in which the end surface 34a of the shaft approaches the end surface 33e of the shaft portion 33a of the fixed iron core 33. Therefore, the plunger 34 moves by exciting the coil 32.

Further, the plunger 34 moves in a direction in which the end surface 34a of the plunger 34 approaches the end surface 33e of the shaft portion 33a of the fixed iron core 33, and the end surface 34a of the plunger 34 is attracted to the end surface 33e of the shaft portion 33a of the fixed iron core 33. It Therefore, the end surface 33e of the shaft portion 33a of the fixed iron core 33 is a suction surface that sucks the plunger 34.

With the movement of the plunger 34, the shaft member 26 and the spool valve 15 are moved in the direction in which the valve body 15v is separated from the first valve seat 23 by the urging force of the valve body spring 28, and the valve body 15v is moved to the second valve. Sit on the seat 24. As a result, as shown in FIGS. 1 and 2, the supply port 17 and the output port 18 communicate with each other through the communication hole 20e, the inside of the extending portion 20b, and the valve chamber 25, and are supplied from the supply port 17. The fluid is supplied to the fluid pressure device via the communication hole 20e, the inside of the extending portion 20b, and the valve chamber 25.

Further, when the energization of the coil 32 is stopped, the magnetomotive force of the coil 32 is not generated, but the attraction force of the magnet 38 overcomes the biasing force of the plunger spring 35, and the end surface 34a of the plunger 34 is fixed to the shaft portion 33a of the fixed iron core 33. It is self-held while being adsorbed on the end face 33e of Therefore, when the coil 32 is de-energized while the end surface 34a of the plunger 34 is attracted to the end surface 33e of the shaft portion 33a of the fixed iron core 33, the attraction force of the magnet 38 causes the attraction force of the magnet 38 to urge the plunger spring 35. The urging force of the plunger spring 35 is set so as to overcome. Therefore, the magnet 38 holds the plunger 34 in a state of being attracted to the end surface 33e of the shaft portion 33a of the fixed iron core 33.

As shown in FIG. 4, for example, when the current supplied to the coil 32 is in the reverse direction, the fixed iron core 33→the first magnetic core 39→the magnetic frame 30→the A magnetic circuit through which magnetic flux passes is formed in the order of 2 magnetic core 40→plunger 34→fixed iron core 33. The direction in which the magnetic flux of the magnetic circuit passes is opposite to the direction in which the magnetic flux of the magnet 38 passes. Then, the magnetomotive force of the coil 32 reduces the attractive force of the magnet 38.

As shown in FIGS. 5 and 6, when the attractive force of the magnet 38 is reduced by the magnetomotive force of the coil 32, the end surface 34 a of the plunger 34 is moved to the end surface of the shaft portion 33 a of the fixed iron core 33 by the urging force of the plunger spring 35. The plunger 34 moves in the direction away from 33e. The urging force of the plunger spring 35 overcomes the urging force of the valve body spring 28, so that the end surface 34b of the plunger 34 presses the spool valve 15 and the shaft member 26 while contacting the shaft portion 15a of the spool valve 15, The valve body 15v moves in a direction away from the second valve seat 24, and the valve body 15v seats on the first valve seat 23. As a result, the output port 18 and the discharge port 19 communicate with each other via the valve chamber 25 and the second hole 16b, and the fluid flows from the output port 18 to the outside via the valve chamber 25, the second hole 16b, and the discharge port 19. Is discharged.

Further, when the power supply to the coil 32 is stopped, the magnetomotive force of the coil 32 is not generated. At this time, since the end surface 34a of the plunger 34 is separated from the end surface 33e of the shaft portion 33a of the fixed iron core 33, the urging force of the plunger spring 35 overcomes the attraction force of the magnet 38 and the end surface 34a of the plunger 34 is fixed. The iron core 33 is held by itself while being separated from the end surface 33e of the shaft portion 33a of the iron core 33. Therefore, when the coil 32 is de-energized with the end surface 34a of the plunger 34 separated from the end surface 33e of the shaft portion 33a of the fixed iron core 33, the urging force of the plunger spring 35 becomes the attraction force of the magnet 38. The biasing force of the plunger spring 35 is set so as to overcome.

As described above, in the self-holding solenoid valve 10, when switching between the state in which the supply port 17 and the output port 18 communicate with each other and the state in which the output port 18 and the discharge port 19 communicate with each other, the coil 32 is switched to the energized state. To do. Then, in the self-holding solenoid valve 10, when the supply port 17 and the output port 18 are maintained in communication with each other or the output port 18 and the discharge port 19 are maintained in communication with each other, the coil 32 is connected to the coil 32. There is no need to energize.

Also, when the coil 32 is de-energized when the end surface 34a of the plunger 34 is adsorbed to the end surface 33e of the shaft portion 33a of the fixed iron core 33, if the separation manual shaft 43 is pressed, The tip end of the shaft 43 projects from the manual shaft accommodating hole 42, and the inclined surface 43a of the tip end of the detaching manual shaft 43 comes into sliding contact with the corner 34e of the manual shaft recess 34d. Due to the slidable contact between the inclined surface 43a of the distal end portion of the detaching manual shaft 43 and the corner portion 34e of the manual shaft recess 34d, the end surface 34a of the plunger 34 is separated from the end surface 33e of the shaft portion 33a of the fixed iron core 33. The plunger 34 moves. Then, the plunger 34 presses the spool valve 15 and the shaft member 26, the valve body 15v moves in a direction away from the second valve seat 24, and the valve body 15v is seated on the first valve seat 23. As a result, the output port 18 and the discharge port 19 communicate with each other via the valve chamber 25 and the second hole 16b. As described above, in the self-holding solenoid valve 10 of the present embodiment, by pressing the detaching manual shaft 43, the supply port 17 and the output port 18 communicate with each other without energizing the coil 32. Can be switched to a state in which the output port 18 and the discharge port 19 communicate with each other, and the operation of the self-holding solenoid valve 10 can be confirmed.

Then, by releasing the pressing of the separation manual shaft 43, the separation manual shaft 43 is returned to the original position before the separation manual shaft 43 was pressed by the biasing force of the return spring 44. At this time, since the end surface 34a of the plunger 34 is separated from the end surface 33e of the shaft portion 33a of the fixed iron core 33, the urging force of the plunger spring 35 overcomes the attraction force of the magnet 38 and the end surface 34a of the plunger 34 is fixed. The iron core 33 is held by itself while being separated from the end surface 33e of the shaft portion 33a of the iron core 33.

When the coil 32 is de-energized with the end surface 34a of the plunger 34 separated from the end surface 33e of the shaft portion 33a of the fixed iron core 33, the suction manual shaft 21 is directed toward the shaft portion 26c. When pushed, the suction manual shaft 21 comes into contact with the shaft portion 26c, and the shaft portion 26c and the spool valve 15 are pushed by the suction manual shaft 21. The shaft portion 26c and the spool valve 15 move in a direction in which the valve body 15v moves away from the first valve seat 23, and the end surface 34a of the plunger 34 approaches the end surface 33e of the shaft portion 33a of the fixed iron core 33. The plunger 34 moves, and the valve element 15v is seated on the second valve seat 24. As a result, the supply port 17 and the output port 18 communicate with each other through the communication hole 20e, the inside of the extending portion 20b, and the valve chamber 25. As described above, in the self-holding solenoid valve 10 of the present embodiment, by pressing the suction manual shaft 21, the output port 18 and the discharge port 19 communicate with each other without energizing the coil 32. Can be switched to a state in which the supply port 17 and the output port 18 communicate with each other, and the operation of the self-holding solenoid valve 10 can be confirmed.

Then, by releasing the pressing force of the suction manual shaft 21, the suction manual shaft 21 is returned to the original position before the suction manual shaft 21 was pressed by the urging force of the valve body spring 28. At this time, the attraction force of the magnet 38 overcomes the urging force of the plunger spring 35, so that the end surface 34a of the plunger 34 is self-held while being attracted to the end surface 33e of the shaft portion 33a of the fixed iron core 33.

As shown in FIGS. 3 and 4, a detection terminal 47 is provided in a protruding manner at the tip of the outer peripheral surface of the extending portion 30b of the magnetic frame 30. The protruding end of the detection terminal 47 is electrically connected to the control board 50. A part of the connection block 13 is interposed between the detection terminal 47 and the detection frame 46. Therefore, the detection terminal 47 is electrically connected to the fixed iron core 33 through the magnetic frame 30 and the first magnetic core 39, which are magnetic circuit forming components, while being insulated from the detection frame 46.

The detection frame 46 is electrically connected to the plunger 34 via the plunger spring 35 while being insulated from the fixed iron core 33. An end portion of the terminal portion 46b of the detection frame 46 on the opposite side of the main body portion 46a projects from the connection block 13 and is electrically connected to the control board 50. An annular seal member 48 is provided between the terminal portion 46 b of the detection frame 46 and the connection block 13. The sealing material 48 suppresses the leakage of fluid from the inside of the connecting block 13 via the terminal portion 46 b of the detection frame 46 and the connecting block 13. Further, the detection frame 46 is configured to be electrically connected to the detection terminal 47 when the plunger 34 is attracted to the fixed iron core 33.

The microcomputer 51 measures the capacitance (electrostatic capacitance) generated between the end surface 34a of the plunger 34 and the end surface 33e of the shaft portion 33a of the fixed iron core 33 between the detection frame 46 and the detection terminal 47, The position of the plunger 34 is detected based on the change in capacitance. Therefore, the microcomputer 51 measures the capacitance generated between the plunger 34 and the end surface 33e of the fixed iron core 33 between the detection frame 46 and the detection terminal 47, and based on the capacitance change, It functions as a position detector that detects the position. Therefore, in the present embodiment, the position detection device 60 for detecting the position of the plunger 34 includes the detection frame 46, the detection terminal 47, and the microcomputer 51 that is the position detection unit.

Here, the capacitance is “C”, the dielectric constant is “ε”, the area of the end surface 34a of the plunger 34 and the end surface 33e of the fixed iron core 33 is “S”, and the area between the end surface 34a of the plunger 34 and the end surface 33e of the fixed iron core 33 is When the distance is “L”, the following equation (1) is established.

Therefore, the capacitance value increases as the distance between the end surface 34a of the plunger 34 and the end surface 33e of the fixed iron core 33 decreases, and the distance between the end surface 34a of the plunger 34 and the end surface 33e of the fixed iron core 33 increases. Get smaller.

Next, the operation of this embodiment will be described.
For example, when the end surface 34a of the plunger 34 is attracted to the end surface 33e of the fixed iron core 33 and the valve body 15v is seated on the second valve seat 24, and the energization of the coil 32 is stopped, the self-holding electromagnetic It is assumed that an external force such as vibration or impact is applied to the valve 10, and the plunger 34 moves in a direction in which the end surface 34a of the plunger 34 is separated from the end surface 33e of the fixed iron core 33. Then, the distance between the end surface 34a of the plunger 34 and the end surface 33e of the fixed iron core 33 increases, and the capacitance value measured by the microcomputer 51 decreases. The microcomputer 51 detects the position of the plunger 34 based on the change in the capacitance.

Further, for example, when the end surface 34a of the plunger 34 is separated from the end surface 33e of the shaft portion 33a of the fixed iron core 33, the valve body 15v is seated on the first valve seat 23, and the energization of the coil 32 is stopped. In the above, it is assumed that an external force such as vibration or impact is applied to the self-holding solenoid valve 10 and the end face 34a of the plunger 34 moves in a direction approaching the end face 33e of the fixed iron core 33. Then, the distance between the end surface 34a of the plunger 34 and the end surface 33e of the fixed iron core 33 decreases, and the capacitance value measured by the microcomputer 51 increases. The microcomputer 51 detects the position of the plunger 34 based on the change in the capacitance.

In the above embodiment, the following effects can be obtained.
(1) The microcomputer 51 measures the capacitance generated between the end surface 34a of the plunger 34 and the end surface 33e of the fixed iron core 33 between the detection frame 46 and the detection terminal 47, and based on the change in the capacitance. , The position of the plunger 34 is detected. Therefore, compared with the case where the position of the plunger 34 is detected by monitoring the change in the inductance of the coil 32 as in the prior art, for example, a complicated circuit configuration is not required and the detection accuracy is improved. And an inexpensive configuration can be achieved. Further, unlike the prior art, it is not necessary to supply the pulse current to the coil 32 in order to detect the position of the plunger 34 while the supply of the drive current to the coil 32 is stopped. Therefore, it is possible to detect the position of the plunger 34 while avoiding that the magnetomotive force of the coil 32 becomes small and the movement of the plunger 34 becomes unstable due to the excitation of the coil 32.

(2) The insertion portion 39c of the first magnetic core 39 is in contact with the fixed iron core 33 while penetrating the magnet 38. The detection terminal 47 is electrically connected to the fixed iron core 33 via the magnetic frame 30 and the first magnetic core 39. According to this, for example, compared to the case where the insertion portion 39c of the first magnetic core 39 does not penetrate the magnet 38 and the magnet 38 is interposed between the first magnetic core 39 and the fixed iron core 33. Electricity easily flows between the fixed iron core 33 and the detection terminal 47. Therefore, the capacitance between the detection frame 46 and the detection terminal 47 in the microcomputer 51 can be accurately measured, and the position of the plunger 34 can be accurately detected.

(3) The detection frame 46 is molded by the connection block 13, and the sealing material 48 is provided between the detection frame 46 and the connection block 13. According to this, it is possible to suppress the leakage of the fluid from the inside of the connection block 13 through the space between the terminal portion 46 b of the detection frame 46 and the connection block 13 by the sealing material 48.

(4) The position detection unit of the position detection device 60 is the microcomputer 51 mounted on the control board 50 that controls the energization of the coil 32. The detection frame 46 and the detection terminal 47 are electrically connected to the control board 50. According to this, it is not necessary to separately provide a position detection unit separately from the microcomputer 51, and the configuration of the self-holding solenoid valve 10 can be simplified.

(5) For example, even if the plunger 34 tilts while the plunger 34 is moving and the plunger 34 stops at an abnormal position, the position of the plunger 34 is determined by the value of the capacitance measured by the microcomputer 51. Can be accurately detected. Therefore, the malfunction of the plunger 34 can be accurately detected.

(6) Since the microcomputer 51 detects the position of the plunger 34 based on the change in capacitance, it must detect the position of the plunger 34 without being affected by the magnetic flux of the magnetic circuit formed by the excitation of the coil 32. You can Therefore, for example, even when the power supply is an AC power supply and the magnetic flux of the magnetic circuit formed by the excitation of the coil 32 is constantly changing, the position of the plunger 34 can be accurately detected.

(7) A detection frame 46 electrically insulated from the fixed iron core 33 and electrically connected to the plunger 34, and a detection terminal 47 electrically connected to the fixed iron core 33 are provided. Therefore, the capacitance between the fixed iron core 33 and the plunger 34 can be measured, and the position of the plunger 34 can be detected without supplying a current to the coil 32.

The above embodiment may be modified as follows.
In the embodiment, the insertion portion 39c of the first magnetic core 39 may not penetrate the magnet 38, and the magnet 38 may be interposed between the first magnetic core 39 and the fixed iron core 33.

In the embodiment, the detection frame 46 may not be molded by the connecting block 13 and the entire detection frame 46 may be exposed. The point is that the detection frame 46 should be in a state of being insulated from the fixed iron core 33 and the detection terminal 47.

In the embodiment, the sealing material 48 may not be provided between the detection frame 46 and the connection block 13.
In the embodiment, a position detecting unit may be separately provided in addition to the microcomputer 51.

-In embodiment, the self-holding solenoid valve 10 may be a 5-port solenoid valve.
In the embodiment, the position detection device 60 does not have to detect the position of the plunger 34 of the solenoid 31 used in the self-holding solenoid valve 10. For example, in the solenoid plunger used in the pilot solenoid valve, The position may be detected.

13... Connection block made of a resin material, 30... Magnetic frame which is a magnetic circuit forming component, 31... Solenoid, 32... Coil, 33... Fixed iron core, 33e... End surface which is a suction surface, 34... Plunger, 35... Plunger spring, 38... Magnet, 39... 1st magnetic core which is a magnetic circuit formation component, 40... 2nd magnetic core which is a magnetic circuit formation component, 46... Detection frame, 47... Detection terminal, 48... Seal material, 50... Control Substrate, 51... Microcomputer functioning as position detecting unit, 60... Position detecting device.

Claims (4)

A coil,
A plunger that moves by exciting the coil,
A fixed iron core having an attraction surface for attracting the plunger;
A plunger position detecting device for a solenoid, comprising: a plunger spring that biases the plunger in a direction in which the plunger is separated from the attraction surface,
A conductive detection frame electrically connected to the plunger via the plunger spring in a state of being insulated from the fixed iron core,
A detection terminal electrically connected to the fixed core in a state of being insulated from the detection frame,
A capacitance generated between the plunger and the suction surface is measured between the detection frame and the detection terminal, and a position detection unit that detects the position of the plunger based on the change in the capacitance. And a solenoid plunger position detecting device. The solenoid contacts the fixed iron core while penetrating a magnet that holds the plunger in a state of being attracted to the attracting surface, and magnetizes the coil by exciting the coil to form a magnetic circuit in cooperation with the fixed iron core. Has circuit forming parts,
The position detecting device for a solenoid plunger according to claim 1, wherein the detecting terminal is electrically connected to the fixed iron core through the magnetic circuit forming component. The detection frame is molded with a resin material,
3. The solenoid plunger position detecting device according to claim 1, wherein a sealing material is provided between the detection frame and the resin material. The position detection unit is a microcomputer mounted on a control board that controls energization of the coil,
The position detecting device for a solenoid plunger according to any one of claims 1 to 3, wherein the detection frame and the detection terminal are electrically connected to the control board.