JP2010174965A - Solenoid valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve durability of a solenoid valve by maintaining sealing performance of a valve element for a long time. <P>SOLUTION: A valve seat 33 having a communicating hole 32 communicating a supply port 30 and an output port 34 is provided in a valve housing. A valve element 40 has a contacting surface 58 facing a seat surface of the valve seat 33; a spring force acting in a direction closing the communicating hole 32 is applied by a spring member 47 to the valve element 40; the communicating hole 32 is opened by the valve element 40 when a plunger 46 is driven by energizing a coil 43; a seal section sealing the communicating hole 32 by elastically deforming the valve element 40 when the valve element 40 closes the communicating hole 32 is provided in the valve seat 33; and a stopper face, regulating elastic deformation at this time, is provided in the valve seat. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electromagnetic valve that switches a flow path by driving a poppet type valve element with a solenoid.

  In a direct acting solenoid valve that opens and closes a flow path by directly driving a poppet type valve element by a movable iron core of a solenoid, that is, a plunger, the valve element is driven in a direction perpendicular to the valve seat surface. This type of solenoid valve includes a 2-port type and a 3-port type. As described in Patent Document 1, the 2-port type solenoid valve has a communication hole that communicates a primary supply port to which a fluid is supplied from the outside and a secondary output port that discharges the fluid to the outside. The valve body is pressed against the formed valve seat. As described in Patent Documents 2 and 3, the three-port type is a supply side in which a supply port and an output port are communicated with one of two valve seats provided to face each other through a valve body. The other valve seat is formed with a discharge side communication passage for communicating the output port and a discharge port for discharging the fluid returned from the outside to the output port. Under the state where the valve body is pressed against one valve seat and the communication hole for supply is closed, the valve body is separated from the other valve seat and the communication passage is opened.

  A solenoid valve using such a direct acting solenoid valve as a pilot valve is an indirect operation type. The indirectly operated solenoid valve has a main valve shaft provided with a piston and a pilot valve that switches between supplying and discharging fluid to the piston, and the main valve shaft is driven by fluid supplied to the piston via the pilot valve. The flow path is switched by a plurality of spool type valve bodies provided on the main valve shaft. Furthermore, as an indirect operation type solenoid valve, as described in Patent Document 4, there is a type in which a poppet type valve element is provided on a spindle driven by a movable iron core of a solenoid, that is, a main valve shaft.

Japanese Utility Model Publication No. 4-106576 JP 2003-278929 A JP 2003-278930 A Japanese Patent Laid-Open No. 9-203477

  Both direct acting solenoid valves and indirectly operated solenoid valves using this as a pilot valve have a poppet type valve body that is pressed against the valve seat by a solenoid plunger. The valve body is made of elastic material such as rubber. It is formed by the body. A spring force in a direction toward the valve seat is applied to the valve body by a spring member provided on the plunger, and the communication hole formed in the valve seat is closed when the valve body is pressed against the valve seat. Under the state where the valve body is pressed against the valve seat and the communication hole is closed, a spring force is applied to the elastic valve body, and fluid leakage from the primary side port to the secondary side port is sealed. .

  If the entire seat surface of the valve seat is a flat surface and the valve body is brought into surface contact with the entire seat surface, that is, the entire valve seat surface, the valve body can be secured to ensure a sealing property between the valve body and the valve seat surface. It is necessary to increase the applied spring force. In order to ensure the sealing performance, it is necessary to elastically deform the valve body by the spring force and keep the communication hole closed. However, when the spring force is increased, it is necessary to increase the power supplied to the solenoid in order to open the valve body against the spring force. In order to ensure the sealing performance by the valve body without excessively increasing the power supply, conventionally, the valve seat has an annular diameter smaller than the outer diameter of the valve body, or an annular bead portion that contacts the valve body has When the valve body is pressed against the valve seat, the annular portion bites into the valve body. When the valve seat is bitten into the valve body in this way, the valve body is elastically deformed, and the sealing performance can be improved.

  However, if the valve body is pressed against the annular portion of the valve seat, the electromagnetic valve is incorporated into the actual device and operated after the solenoid valve is manufactured, and when the device is in a resting state. Thus, when the solenoid valve is not operating, the valve body is pressed against the valve seat by the spring force, and the valve body gradually deforms, thereby causing a phenomenon that the valve body sinks into the valve seat. This sinking phenomenon is promoted when the solenoid valve is actually operated to repeatedly turn on and off, an impact force is applied to the valve body, and further the heat of the solenoid is applied. Thus, when the valve body sinks, the trace of the valve seat remains on the contact surface of the valve body, resulting in a distorted state, which becomes an annular recess. If a deep recess remains on the contact surface of the valve body, a seal failure will occur when the valve body comes into contact with the valve seat, and the solenoid valve cannot perform its intended performance. Must be replaced with a new one.

  When the valve body sinks into the valve seat, the stroke of the plunger becomes longer than that at the time of manufacturing the solenoid valve or the design value, so that the minimum operating voltage supplied to the solenoid for driving the valve body becomes higher than the design value. For example, in the case of a solenoid valve with a rating of 24V, even if the minimum operating voltage at the time of manufacture is 18V, when the valve body sinks, the minimum operating voltage increases to about 24V, and the operating characteristics of the solenoid valve Will change.

  An object of the present invention is to improve the durability of a solenoid valve so that the sealing performance of the valve body can be maintained over a long period of time.

  An object of the present invention is to prevent an increase in the minimum operating voltage of a solenoid valve by preventing deformation of the valve body and maintaining the stroke of a plunger that drives the valve body constant over a long period of time.

  The solenoid valve of the present invention is a solenoid valve having a plunger driven by energizing a coil and opening and closing a fluid flow path, and discharges fluid to a supply port to which fluid from a fluid pressure source is supplied and to the outside. A valve housing provided with an output port, a valve seat having a seat surface in which the supply port communicates with the output port and having a seat surface in which the communication hole opens, and an abutment facing the seat surface And a valve body made of an elastic member that moves in a direction to close the communication hole by a spring member, and moves in a direction to open the communication hole when the plunger is driven by energization of the coil. A sealing portion that seals the communication hole by elastically deforming the valve body when the valve body closes the communication hole is provided on the seat surface so as to surround the opening of the communication hole; But The stopper surface for regulating the amount of elastic deformation of the valve body by the sealing portion abuts to the abutment surface under the closed state Kirendoriana and forming on the sheet surface. The solenoid valve according to the present invention is characterized in that the seal portion is provided at a central portion of the seat surface.

  In the solenoid valve according to the present invention, a discharge port for discharging the fluid returned from the outside to the output port is provided in the valve housing, and a communication passage is formed so as to face the valve seat and communicate the discharge port with the output port. The opposed valve seat is provided in the valve housing so as to face the valve seat, and when the valve body closes the communication hole, the communication passage is opened, and when the valve body closes the communication passage, It is characterized by opening a communication hole. The solenoid valve of the present invention has a valve housing hole for reciprocatingly housing a main valve shaft provided with a piston at an end and a plurality of spool valve bodies in the axial direction. A fluid supply channel for supplying fluid, an output channel for discharging fluid to the fluid pressure device, and a discharge channel for discharging fluid returned from the fluid pressure device to the outside communicate with the valve housing hole, respectively. A main valve block formed by supplying the fluid from the fluid pressure source to the piston through the communication hole by energizing the coil, and communicating the supply flow path with the output flow path. The main valve shaft is switched and moved between a position and a position where the output flow path communicates with the discharge flow path.

  According to the present invention, under the state where the valve body is pressed against the valve seat by the spring force, the contact surface of the valve body contacts the stopper surface provided on the valve seat, and the valve by the seal portion of the valve seat Since the elastic deformation amount of the body is restricted, the valve body is prevented from sinking into the valve seat. This prevents residual strain from occurring in the valve body due to the spring force in the direction of closing the communication hole, or the occurrence of traces, and can maintain the sealing performance of the valve body over a long period of time. The durability of the solenoid valve is improved.

  Since the occurrence of subsidence of the valve body is prevented, the stroke of the plunger that drives the valve body does not increase even if the electromagnetic valve is used for a long period of time, and maintains a constant stroke. As a result, the minimum operating voltage supplied to the coil does not increase, and stable operating characteristics are maintained over a long period of time, thereby improving the durability of the solenoid valve.

  Since the valve body is pressed against the stopper surface of the valve seat to restrict the elastic deformation amount of the valve body by the seal portion, the seal portion can be made small. When the seal part is made smaller, the area of the seal part becomes smaller. Therefore, even if the spring force for pressing the valve element against the valve seat is reduced, the pressure per unit area of the seal part, that is, the surface pressure, can be sufficiently secured. Can do. Thereby, a sufficient sealing property can be ensured. In addition, since the spring force is small, the solenoid current for driving the plunger against the spring force can be reduced, and the current consumption of the solenoid can be reduced to realize low power consumption of the solenoid.

It is sectional drawing which shows the solenoid valve which is one embodiment of this invention. It is an expanded sectional view which shows a part of FIG. (A) is a perspective view which shows the valve body integrated in the valve holder, (B) is 3B-3B sectional view taken on the line in (A), (C) is 3C-3C sectional view taken on the line in (B) It is. It is an expanded sectional view showing a valve seat. It is sectional drawing which expands and shows the valve body in FIG. 1, (A) shows the state from which the solenoid was switched from ON to OFF, and the contact surface of the valve body contacted the seal surface, (B) is a seal | sticker. A state where the contact surface is pressed against the stopper surface after contacting the surface is shown. FIG. 6 is a cross-sectional view showing the same part of FIG. 5 in a solenoid valve as a comparative example, and (A) shows a state in which the solenoid is switched from ON to OFF and the contact surface of the valve body is in contact with the valve seat; (B) shows a state in which the valve body is sunk into the valve seat.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The electromagnetic valve 10 shown in FIG. 1 is an indirect operation type, and has a main valve block 11 having a substantially rectangular parallelepiped shape. The main valve block 11 is formed with a valve housing hole 12 penetrating the main valve block 11 in the longitudinal direction. A main valve shaft 13 is housed in the valve housing hole 12 so as to be reciprocally movable in the axial direction. A first pilot block 15 is fixed to one end of the main valve block 11 via a switching block 14, and second and third two pilot blocks 16 and 17 are fixed to the other end. A valve housing 18 is formed by the main valve block 11, the switching block 14, and the three pilot blocks 15 to 17, and a solenoid block 19 is attached to the valve housing 18.

  As shown in FIG. 1, the main valve block 11 is provided with a supply passage 21 and two output passages 22a and 22b located on both sides of the supply passage 21. Adjacent discharge passages 23 a and 23 b are formed in the main valve block 11, and each communicates with the valve accommodation hole 12. The electromagnetic valve 10 is a 5-port valve because a total of five supply flow paths 21, output flow paths 22a and 22b, and discharge flow paths 23a and 23b are provided as ports to the main valve block 11, respectively. Yes.

  The main valve shaft 13 is provided with a plurality of spool valve bodies 24, and when the main valve shaft 13 is moved to the first position on the right end side as shown in FIG. 22a becomes a communication state, and the output flow path 22b and the discharge flow path 23b become a communication state. In contrast, when the main valve shaft 13 moves to the second position on the left end side, the supply flow path 21 and the output flow path 22b are in communication with each other, and the output flow path 22a and the discharge flow path 23a are in communication with each other. become.

  The electromagnetic valve 10 shown in FIG. 1 is attached to a manifold block (not shown), and a plurality of electromagnetic valves are assembled and attached to the manifold block. However, the solenoid valve 10 having the structure shown in FIG. 1 can be used as a single unit. The manifold block is formed with a common supply channel that communicates with the supply channel 21 in the main valve block 11 of the plurality of solenoid valves 10 and is connected to a fluid pressure supply source. Compressed air is supplied from an air pressure source as an external fluid pressure supply source. The output flow paths 22a and 22b are connected to a fluid pressure device such as a pneumatic cylinder through an output flow path formed in the manifold block. Is opened, the hydraulic device can be directly connected to the main valve block 11. The manifold block is formed with a common discharge flow path communicating with the discharge flow paths 23a and 23b in the main valve block 11 of the plurality of solenoid valves 10, and the compressed air returned from the fluid pressure device is discharged to the discharge flow paths 23a and 23b. It will be discharged to the outside through 23b.

  For example, when one output flow path 22a is connected to the forward pressure chamber of a double-acting pneumatic cylinder and the other output flow path 22b is connected to the reverse pressure chamber, the supply flow path 21 through the output flow path 22a. Thus, the piston rod is moved forward by the compressed air supplied to the forward pressure chamber, and the compressed air in the backward pressure chamber is returned to the output flow path 22b and discharged from the discharge flow path 23b to the outside.

  A piston 25 is disposed at one end of the main valve shaft 13, and a piston 26 having a larger diameter than the piston 25 is disposed at the other end. The small diameter piston 25 is reciprocally accommodated in a pneumatic chamber 27 formed in the pilot block 15, and the large diameter piston 26 is reciprocally accommodated in a pneumatic chamber 28 formed in the pilot block 16. . When compressed air is supplied to the pneumatic chamber 27, a thrust is applied to the main valve shaft 13 in the direction of movement to the first position shown in FIG. 1, and when compressed air is supplied to the pneumatic chamber 28, the main valve shaft. A thrust is applied to 13 in the direction of moving to the second position.

  A supply port 30 communicating with the supply flow path 21 is formed in the pilot block 16. The supply port 30 communicates with the first and second two valve chambers 31 a and 31 b formed by abutting the two pilot blocks 16 and 17 through a communication hole 32. As shown in FIG. 2, each communication hole 32 is formed in a valve seat 33 provided in the pilot block 16 so as to protrude into the valve chambers 31 a and 31 b. The first valve chamber 31 a communicates with the large-diameter pneumatic chamber 28 via the output port 34 a formed in the pilot block 16, and the second valve chamber 31 b communicates with the communication flow formed in the main valve block 11. The small-diameter air pressure chamber 27 communicates with the passage 35 and the output port 34b. The pilot block 17 is formed with a discharge port 37 communicating with a discharge flow path 36 formed in the pilot block 16. The discharge port 37 communicates with each of the valve chambers 31a and 31b via a communication passage 38. Each communication passage 38 faces the valve seat 33 and protrudes into the valve chambers 31a and 31b and is provided in the pilot block 17. Formed on the opposite valve seat 39.

  Thus, the pilot blocks 16 and 17 constitute a valve housing 20 of an electromagnetic valve as a pilot valve. The valve housing 20 is compressed externally with a supply port 30 to which compressed air from a pneumatic pressure source is supplied. Output ports 34 a and 34 b for discharging air are provided, and a discharge port 37 for discharging the compressed air returned from the output ports 34 a and 34 b to the valve chambers 31 a and 31 b is provided.

  In each of the valve chambers 31 a and 31 b, a poppet type valve body 40 made of an elastic member such as rubber is disposed. The valve body 40 is attached to a valve holder 41. As shown in FIG. 1, first and second solenoids 42 a and 42 b are incorporated in the solenoid block 19 so as to correspond to the two valve bodies 40. Each solenoid 42a, 42b has a bobbin 44 around which a coil 43 is wound. A fixed iron core 45 is attached in the bobbin 44, and a movable iron core, that is, a plunger 46 is attached so as to reciprocate in the axial direction. As shown in FIG. 2, the end surface of the plunger 46 is in contact with the end surface of the valve holder 41, and a forward spring member 47 for applying a spring force in the direction toward the valve body 40, that is, in the forward direction, to the plunger 46. Are provided in the solenoids 42a and 42b.

  When the solenoid 43 is deenergized and the coil 43 is de-energized, the plunger 46 is moved forward by the spring force of the forward spring member 47 and the valve body 40 is separated from the counter valve seat 39 and pressed against the valve seat 33. Become. As a result, communication between the supply port 30 and the output port 34 is blocked, and the output port 34 and the discharge port 37 are in communication. Therefore, when both solenoids 42 a and 42 b are OFF, the respective pneumatic chambers 27 and 28 are in communication with the discharge port 37. On the other hand, when the coil is energized and the solenoid is ON, the plunger 46 moves backward against the spring force of the spring member 47 so that the valve element 40 is separated from the valve seat 33 and pressed against the counter valve seat 39. Become. As a result, the supply port 30 and the output port 34 are in communication with each other, and the communication between the output port 34 and the discharge port 37 is blocked. For example, when the coil 43 of the first solenoid 42a is energized, the supply flow path 21 of the main valve block 11 is in communication with the pneumatic chamber 27 via the valve chamber 31a, and the compressed air from the pneumatic source is supplied to the pneumatic chamber. 27, the main valve shaft 13 is in the first position as shown in FIG. On the other hand, when the coil 43 of the second solenoid 42b is energized, the supply flow path 21 is in communication with the pneumatic chamber 28 via the valve chamber 31b, and the compressed air supplied to the pneumatic chamber 28 is mainly used. The valve shaft 13 is driven to the left side in FIG. 1 to be in the second position.

  In FIG. 2, the first solenoid 42a is turned off and the plunger 46 is moved forward toward the valve body 40 by the spring force. The second solenoid 42b is turned on and the plunger 46 is spring-loaded. Shown in reverse movement against force.

  As shown in FIG. 2, a backward spring member 48 is incorporated in the valve chambers 31 a and 31 b in order to apply a spring force to the valve body 40 in a direction away from the valve seat 33. As a result, when the solenoids 42a and 42b are turned on, the valve element 40 is surely moved away from the valve seat 33 toward the counter valve seat 39. The spring force of the backward spring member 48 is set to a value smaller than the spring force of the forward spring member 47.

  As shown in FIG. 1, the main valve block 11 is provided with a bypass passage 51 communicating with the pneumatic chamber 27, and the switching block 14 is provided with a switching operation button 52. The switching operation button 52 is located at a position where the bypass flow path 51 and the pneumatic chamber 27 are communicated with each other to block communication between the communication flow path 35 and the pneumatic chamber 27, and as shown in FIG. The communication with the chamber 27 is interrupted, and the position where the communication channel 35 and the pneumatic chamber 27 communicate with each other can be switched manually.

  As shown in FIG. 1, in the indirectly operated solenoid valve having two solenoids 42a and 42b, when one of the two solenoids 42a and 42b is turned on, the main valve shaft 13 is in either the first or second position. When switched to one side and the solenoids 42a and 42b are turned OFF, the main valve shaft 13 holds the switched position. This type is a double solenoid type. When the solenoid valve 10 is used as this type, as shown in FIG. 1, the switching operation button 52 blocks communication between the bypass flow path 51 and the pneumatic chamber 27, and the communication flow path 35 and the pneumatic chamber 27 are disconnected. The communication state is set.

  On the other hand, when the switching operation button 52 is operated so that the bypass flow path 51 and the pneumatic chamber 27 communicate with each other and the communication between the communication flow path 35 and the pneumatic chamber 27 is blocked, the small-diameter pneumatic chamber 27 is set. In this state, compressed air is always supplied from the external air pressure source via the supply flow path 21. As a result, the main valve shaft 13 is switched only by the second solenoid 42b. That is, when the second solenoid 42b is turned on, the compressed air is supplied to both the pneumatic chambers 27 and 28, and the main valve shaft 13 is moved to the second position due to the area difference between the two pistons 25 and 26. It will be switched to. When the second solenoid 42b is turned OFF, the compressed air supplied to the large-diameter pneumatic chamber 28 is discharged, and the main valve shaft 13 is switched to the first position by the compressed air in the small-diameter pneumatic chamber 27. It will automatically return to that position. As described above, the type that does not include the first solenoid 42a, or the type that does not use the first solenoid 42a even though it includes the first solenoid 42a, performs the switching operation of the main valve stem 13 by only one solenoid 42b. The solenoid valve 10 is a single solenoid type.

  The third pilot block 17 is provided with a manual operation button 53 for operating the valve body 40 by moving the plunger 46 of the solenoid 42a backward by manual operation.

  As shown in FIG. 3, the valve holder 41 has a cylindrical portion 55 in which the valve body 40 is incorporated, and the valve body 40 is abutted against a small diameter portion 56 provided in the cylindrical portion 55, so that the valve body 40 is cylindrical portion 55. It is designed to be incorporated inside. The valve holder 41 has two leg portions 57 protruding from the cylindrical portion 55. The leg portions 57 pass through guide holes (not shown) formed in the pilot block 17, and the rear end surface 57 a is the tip of the plunger 46. It comes in contact with the surface. The front end side portion of the valve body 40 has a smaller diameter than the rear end side portion, and the end portion of the retreating spring member 48 is shown in FIG. 2 in the gap between the small diameter front end side portion and the cylindrical portion 55. Inserted into. The front end surface of the valve body 40 is a contact surface 58 that faces the valve seat 33, and the inner portion of the small-diameter portion 56 of the rear end surface is a contact surface 59 that faces the counter valve seat 39.

  As shown in FIG. 4, the valve seat 33 is formed with a communication hole 32 that allows the supply port 30 and the output port 34 to communicate with each other via a valve chamber 31 a, and the communication hole 32 is a seat surface of the valve seat 33. 61 is opened to the valve chamber 31a at the radial center. On the other hand, a communication passage 38 is formed in the counter valve seat 39 to allow the output port 34 and the discharge port 37 to communicate with each other via the valve chamber 31a. The communication passage 38 is formed in the radial direction of the seat surface 62 of the counter valve seat 39. Opened at the center. Both the first and second sheet surfaces 61 and 62 face each other. The valve seat 33 and the counter valve seat 39 provided so as to protrude into the other valve chamber 31b have the same structure. The valve body 40 mounted in each of the valve chambers 31a and 31b is mounted in the valve chambers 31a and 31b so that the contact surface 58 faces the seat surface 61. Thus, the valve seat 33 as the first valve seat on the supply port 30 side and the counter valve seat 39 as the second valve seat on the discharge port 37 side are opposed to each other via the valve body 40. The valve element 40 disposed between the seat surfaces 61 and 62 facing each other performs the flow path switching operation. Note that the valve body 40 is not shown in FIG.

  An annular seal portion 63 is provided at the center of the seat surface 61 of the valve seat 33 so as to surround the opening of the communication hole 32, and the tip of the seal portion 63 is flat or has a substantially arc shape in cross section. It becomes the sealing surface 61a. The radially outer side of the seal portion 63 is a stopper surface 61b that extends straight in the radial direction, and the seal portion 63 protrudes toward the valve body 40 from the stopper surface 61b. The seal portion 63 is provided at the center portion of the seat surface 61 as shown in the figure, but the seal portion 63 may be provided closer to the outside in the radial direction than this position.

  As shown in FIG. 4, when the outer diameter of the seat surface 61 of the valve seat 33 is D and the projecting dimension of the seal portion 63 from the stopper surface 61b is L, the outer diameter D is 1.6 mm, and the projecting dimension L Is set to about 0.05 mm to 0.1 mm, and the width W in the radial direction is set to about 0.05 mm to 0.1 mm. Thus, since the area of the seal part 63 is very small compared to the stopper surface 61b, the unit area of the seal part 63 per unit area is small even though the spring force for pressing the valve body 40 against the valve seat 33 is small. Sufficient pressure by spring force, that is, surface pressure can be secured. That is, sealing performance can be ensured. Further, since the spring force is small, the solenoid current for driving the plunger 46 against the spring force can be reduced.

  On the other hand, the counter valve seat 39 is provided with a sealing surface 62a that is in contact with the contact surface 59 of the valve body 40 in an annular shape in the center in the radial direction, and is separated from the valve body 40 as it goes radially outward from the seal surface 62a. A tapered surface 62b inclined in the direction is provided on the counter valve seat 39.

  The counter valve seat 39 with which the contact surface 59 of the valve element 40 abuts when the solenoids 42a and 42b are turned on does not have a stopper surface. When the solenoid is ON, the plunger 46 abuts against the fixed iron core 45 and therefore does not move backward any further. That is, the dimension that the valve body 40 sinks toward the counter valve seat 39 is defined in advance as a design value by the dimension of the plunger 46, the dimension of the valve holder 41, and the like. The valve body 40 does not sink toward the counter valve seat 39 beyond the design value. Therefore, the opposed valve seat 39 is not provided with a protruding seal portion. Further, the force for pressing the valve body 40 against the counter valve seat 39 includes the small spring force of the retreating spring member 48, but the main force is the compressed air of the supply port pressing the valve body 40 against the counter valve seat 39. . That is, it has a self-sealing structure that does not depend on spring force or the like.

  As shown in FIG. 2, the valve body 40 driven by the plunger 46 communicates with the output port 34 and the discharge port 37 when the communication hole 32 that connects the supply port 30 and the output port 34 is closed. When the passage 38 is opened and the communication hole 32 is opened, a three-port direct acting solenoid valve is configured to close the communication passage 38.

  FIG. 5A shows a state in which the solenoids 42a and 42b are switched from ON to OFF, and the contact surface 58 of the valve body 40 is in contact with the seal surface 61a. FIG. A state where the contact surface 58 is pressed against the stopper surface 61b after the contact is shown.

  Under the state where the contact surface 58 is in contact with the stopper surface 61 b, the seal portion 63 is in a state where the valve body 40 is partly elastically deformed and bites into the contact surface 58. The amount of elastic deformation of the valve body 40 at this time is set to a value sufficient to ensure the sealing performance by the contact between the seal surface 61a and the contact surface 58, since the contact surface 58 contacts the stopper surface 61b. Is done. Thereby, under the state in which the valve body 40 closes the communication hole 32, it is possible to prevent the valve body 40 from being excessively deformed such that permanent distortion remains in the valve body 40.

  Under the state where the contact surface 58 is in contact with the seat surface 61, the posture of the valve body 40 is held by the stopper surface 61b, so that the annular seal portion 63 contacts the valve body 40 uniformly and as a whole. The occurrence of hits is prevented. Moreover, since the stopper surface 61b is set to have a much larger area than the seal surface 61a, the stopper surface 61b bites into the contact surface 58 even if the contact surface 58 is pressed against the stopper surface 61b. The deformation generated on the contact surface 58 of the valve body 40 by the seal portion 63 is within the proportional limit of the elastic body. As a result, even if a spring force is applied to the valve body 40, the valve body 40 maintains a desired sealing characteristic for a long period of time without generating any residual distortion.

  Therefore, even if the non-use period of the solenoid valve 10 becomes long or the solenoid valve 10 is used for a long period of time, the valve body 40 sinks into the valve seat 33 and the trace of the valve seat 33 becomes a mark of the valve body 40. It does not occur on the contact surface 58, and the sealing performance can be secured for a long period. Thereby, the lifetime of the solenoid valve 10 can be lengthened, and the durability of the solenoid valve 10 can be remarkably improved.

  In addition, since the occurrence of the sinking phenomenon of the valve body 40 with respect to the valve seat 33 is prevented, the stroke of the plunger 46 when the valve body 40 is moved away from the seat surface 61 from the state in which the valve body 40 is in contact with the seat surface 61. Is always kept constant, and the stroke of the plunger 46 does not increase even when the electromagnetic valve 10 is used for a long period of time. As a result, the minimum operating voltage of the solenoids 42a and 42b does not increase, the electromagnetic valve maintains stable operating characteristics over a long period of time, and the durability of the electromagnetic valve 10 is significantly improved.

  Since the contact surface 58 comes into contact with the entire seat surface 61 together with the seal surface 61 a, it is possible to prevent the seal portion 63 from coming into contact with each other, and the valve body 40 is attached to the valve seat 33. The spring force of the spring member 47 for pressing against the seat surface 61, that is, the plunger spring can be reduced. If the spring force can be reduced, the current value of the solenoids 42a and 42b that overcomes the spring force to drive the plunger 46 can be reduced, so that low power consumption of the solenoid with low current consumption can be realized. .

  6 is a cross-sectional view showing the same part of the electromagnetic valve shown in FIG. 5 as a comparative example, and FIG. 6A shows that the solenoid is switched from ON to OFF so that the contact surface 58 of the valve body 40 is the valve seat 33. FIG. 6B shows a state in which the valve body 40 is sunk into the valve seat 33.

  Since the conventional solenoid valve is not provided with a stopper surface on the valve seat 33, the pressing force of the spring member is not applied when the valve body 40 is in contact with the sealing surface of the valve seat 33 and the communication hole 32 is closed. It will be added to the whole part which contacts an annular sealing surface. For this reason, as shown in FIG. 6B, the phenomenon that the valve body 40 sinks into the valve seat 33 is inevitable.

  When the area of the seal surface is increased to prevent the sinking phenomenon, the spring force of the spring member 47 depends on the area of the seal surface in order to secure the pressure by the spring per unit area of the seal surface, that is, the surface pressure. Need to be large. Then, it is necessary to increase the force of the solenoid that attracts the plunger 46 against the spring force of the spring member 47. That is, since the solenoid current is set to be large, the current consumption increases and the heat generation amount also increases. As a result, the life of the valve body, which is a rubber product, is shortened, so that the durability of the solenoid valve is impaired. On the other hand, in the solenoid valve 10 of the present invention, the sinking phenomenon does not occur and the surface pressure of the sealing surface is secured.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. For example, FIG. 1 shows an indirect operation type electromagnetic valve using a valve body 40 as a direct acting valve as a pilot valve, which corresponds to two pilot blocks 16 and 17 provided with a valve seat 33 and a counter valve seat 39. The present invention can also be applied to a direct acting electromagnetic valve of a type having a valve housing and in which the valve body 40 is driven by a solenoid. When the present invention is embodied as a direct acting solenoid valve, as described in Patent Document 1, a primary side port corresponding to the supply port 30 and a secondary port corresponding to the output port 34 are used. The present invention can also be applied to a two-port type having side ports and only opening and closing between these ports. As a 2-port type direct acting type, it is also possible to communicate the primary port with the valve chamber and communicate the secondary port with the communication hole. FIG. 1 shows a 5-port indirectly-actuated solenoid valve, but the present invention can also be applied to a 3-port indirectly-actuated solenoid valve.

DESCRIPTION OF SYMBOLS 10 Solenoid valve 11 Main valve block 12 Valve accommodating hole 13 Main valve shaft 14 Switching block 15-17 Pilot block 18 Valve housing 20 Valve housing 21 Supply flow path 22a, 22b Output flow path 23a, 23b Discharge flow path 25, 26 Piston 27 , 28 Pneumatic chamber 30 Supply port 31a, 31b Valve chamber 32 Communication hole 33 Valve seat 34a, 34b Output port 35 Communication channel 36 Discharge channel 37 Discharge port 38 Communication channel 39 Counter valve seat 40 Valve element 41 Valve holder 42a, 42b Solenoid 43 Coil 44 Bobbin 45 Fixed iron core 46 Plunger 47 Spring member 48 Spring member 51 Bypass flow path 58, 59 Contact surface 61 Sheet surface 61a Seal surface 61b Stopper surface 62 Sheet surface 63 Seal portion

Claims (4)

An electromagnetic valve having a plunger driven by energization of a coil and opening and closing a fluid flow path;
A valve housing provided with a supply port for supplying fluid from a fluid pressure source and an output port for discharging fluid to the outside;
A valve seat having a seat surface in which the communication port is formed and a communication hole for communicating the supply port with the output port is formed;
Elasticity having a contact surface facing the seat surface and moving in a direction to close the communication hole by a spring member, and moving in a direction to open the communication hole when the plunger is driven by energizing the coil A valve body made of a member,
When the valve body closes the communication hole, a seal portion that elastically deforms the valve body and seals the communication hole is provided on the seat surface so as to surround the opening of the communication hole,
A stopper surface is formed on the seat surface to restrict the amount of elastic deformation of the valve body by the seal portion while the valve body is in contact with the contact surface with the communication hole closed. Solenoid valve.   2. The electromagnetic valve according to claim 1, wherein the seal portion is provided at a central portion of the seat surface.   3. The electromagnetic valve according to claim 1, wherein a discharge port for discharging the fluid returned from the outside to the output port is provided in the valve housing, and the discharge port communicates with the output port so as to face the valve seat. A counter valve seat having a communication passage is provided in the valve housing so as to face the valve seat, and the valve body opens when the valve body closes the communication hole, and the valve body closes the communication passage. A solenoid valve characterized in that the communication hole is opened when the   4. The electromagnetic valve according to claim 3, wherein a valve housing hole is formed in which a main valve shaft provided with a piston at an end portion thereof and provided with a plurality of spool valve bodies is reciprocally movable in the axial direction, and the fluid A supply flow path for supplying fluid from the pressure source, an output flow path for discharging fluid to the fluid pressure device, and a discharge flow path for discharging the fluid returned from the fluid pressure device to the outside respectively. A main valve block formed in communication with the coil, and by supplying current to the coil, fluid from the fluid pressure source is supplied to the piston through the communication hole, and the supply flow path is used as the output flow path. An electromagnetic valve characterized in that the main valve shaft is switched and moved between a position for communication and a position for communicating the output flow path with the discharge flow path.

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