WO2005064213A1

WO2005064213A1 - Three-port solenoid valve

Info

Publication number: WO2005064213A1
Application number: PCT/KR2004/003377
Authority: WO
Inventors: Yun-Boon Lee
Original assignee: Aser Tech Co., Ltd.
Priority date: 2003-12-31
Filing date: 2004-12-21
Publication date: 2005-07-14
Also published as: KR20050069454A

Abstract

Provided is a three-port solenoid valve that can be made compact and mass-produced through synthetic resin injection molding. The solenoid valve includes a valve body comprised of two adhered body blocks, and a valve room formed between the two body blocks. A supply port, a load port, and an exhaust port pass through the valve room, and a valve mechanism alternately opening and closing the supply port and the exhaust port is inserted into the valve room. The valve mechanism interlocks with a plunger of a solenoid mechanism. Each of the body blocks can be made of a synthetic resin material through injection molding, and the valve mechanism inserted into the valve room can be stably operated and easily managed and assembled, thereby increasing the lifetime and performance of the valve.

Description

THREE-PORT SOLENOID VALVE

Technical Field The present invention relates to a three-port solenoid valve, and more particularly, to a new valve that can be made compact and mass-produced through synthetic resin injection molding.

Background Art Directional control valves are well known devices used to control the flow of fluid in a pneumatic circuit or a hydraulic circuit. Slide spool valves are mainly used as directional control valves. However, slide spool valves have disadvantages in that a cylindrical spool bore in a valve body should be processed with high precision, and have a structural limitation in that they cannot be mass-produced through synthetic resin injection molding due to the shape of a valve room with a great diameter extending in the spool bore. Also, since the slide spool valves cannot be formed of iron that erodes due to moisture or the like, the spool bore and the valve room should be processed after aluminum die casting. Accordingly, the manufacturing costs are high, productivity is reduced due to the complicated manufacturing processes, and miniaturization is difficult to be achieved. Three-port solenoid valves, one of the directional control valves, are generally used as a pair to change the direction of motion of a pneumatic or hydraulic actuator. Also, the three-port solenoid valves are widely used as pilot valves to control a huge amount of fluid. Since the solenoid valves are operated using an electrical signal, they are easy to use in an automatic control, remote control, and emergency stop, and have fast and accurate response time. However, since the solenoid valves are directly operated using an electrical thrust of a solenoid, they are suitable for the control of a small amount of fluid. Accordingly, the solenoid valves need to be made compact. U.S. Patent No. 6,213,445 discloses a solenoid valve that has a different structure from a conventional slide spool valve to control the flow of fluid. The disclosed solenoid valve includes three ports, valve seats for a supply port and an exhaust port among the three ports, and two valve members opening and closing the valve seats. One of the two valve members for the valve seat at a supply port side is coupled to a plunger of a solenoid, and the other one of the two valve members at an exhaust port side is accommodated in a valve room formed in a valve body and interlocks with the valve seat at the supply port side through a rod structure passing through the valve body.

Brief Description of the Drawings FIG. 1 is a perspective view of a three-port solenoid valve according to an embodiment of the present invention. FIG. 2 is a cross-sectional view illustrating essential parts of a coupling structure among body blocks of a valve body of the three-port solenoid valve shown in FIG. 1. FIG. 3 is a side view illustrating essential parts of a coupling structure between a solenoid mechanism and the valve body of the three-port solenoid valve shown in FIG. 1. FIG. 4A is a longitudinal sectional view of an internal structure of the three-port solenoid valve shown in FIG. 1 , which is in a normal state. FIG. 4B is a longitudinal sectional view of the internal structure of the three-port solenoid valve shown in FIG. 1 , which is in a converted state. FIG. 5 is a cross-sectional view illustrating essential parts of an interlocking structure between a plunger and a valve mechanism of the three-port solenoid valve shown in FIG. 1. FIG. 6 is a partial cut away perspective view of the valve mechanism used in the three-port solenoid valve shown in FIG. 1.

Detailed Description of the Invention Technical Goal of the Invention Since the valve disclosed in U.S. Patent No. 6,213,445 permits the valve seats to have a very short stroke, the size of the solenoid mechanism can be reduced, and the valve body and the valve member can be made compact. In particular, since the valve body can be manufactured by synthetic resin injection molding, productivity can be improved. However, since the fluid path structure of the valve body is complicated, die design is difficult to be established, a lot of parts including a valve spring are additionally required to separate the valve members into one at the supply port part and the other at the exhaust port side, and the parts are difficult to be managed and assembled. In addition, since the interlocking structure of the separated valve members is weak, a lot of errors occur when the valve operates. The present invention provides a three-port solenoid valve, which can be made compact, can be mass-produced through synthetic resin injection molding, can reduce the number of parts by alternately opening and closing a supply port and an exhaust port in one valve room, and can make the parts easily managed and assembled.

The structure of the Invention In accordance with an aspect of the present invention, there is provided a three-port solenoid valve comprising: a valve body including a plurality of ports comprised of a supply port, a load port, and an exhaust port through each of which fluid enters and exits, and a valve room through which the plurality of ports pass; a solenoid mechanism coupled to the valve body, driven to produce an electrical thrust using an external electrical signal, and including a plunger moved forward and backward due to the electrical thrust; and a valve mechanism movably accommodated in the valve room of the valve body and interlocking with the plunger of the solenoid mechanism to alternately open and close the supply port and the exhaust port among the ports passing through the valve room. The valve body may be formed by adhering two body blocks that are separated using the valve room as a border. The solenoid mechanism may comprise: a solenoid coil excited by an external electrical signal and producing an electrical thrust; a coil bobbin wound with the solenoid coil; the plunger movably inserted into the coil bobbin and pulled due to the electrical thrust of the solenoid coil; and a plunger spring elastically restoring the plunger when the electrical thrust of the solenoid coil is removed. The valve mechanism may comprise: a valve member made of an elastic material and having valve elements formed at both ends thereof to alternately open and close the supply port and the exhaust port passing through the valve room; a valve holder allowing the valve member to be fitted thereinto and having an interlocking protrusion that passes through an inner wall of the valve room and contacts and interlocks with an end of the plunger of the solenoid mechanism; and a valve spring elastically supporting the valve holder and pushing the valve holder in a direction opposite to the plunger.

The Effect of the Invention As described above, the valve body of the three-port solenoid valve is formed by adhering the two body blocks that are separated using the internal valve room as a border. Each of the body blocks can be made of a synthetic resin material through injection molding, thereby reducing the cost of the valve. The rate of defective products can be reduced because complicated post-processes are omitted, and the manufacturing costs of the valve can be remarkably reduced because the valve can be mass-produced and the valve can be made compact. Since the fluid path structure of the valve body is simple, die design can be easily made. The number of parts can be reduced, and the parts can be easily managed and assembled. In addition, since the interlocking structure of the valve member is structurally stable, operational errors rarely occur, thereby increasing productivity and lifetime.

Best mode for carrying out the Invention The present invention will now be described more fully with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. FIG. 1 is a perspective view of a three-port solenoid valve according to an embodiment of the present invention. The three-port solenoid valve includes a valve body 10 and a solenoid mechanism 20. The valve body 10 is comprised of two body blocks 10a and 10b, and has bolt fixing parts 1 1 to be fixed to a typical manifold block (not shown). It is preferable that the bolt fixing parts 11 having semi-cylindrical shapes be formed at a first edge of a side surface of the first body block 10a and at a second edge of a side surface of the second body block 10b located opposite in a diagonal direction to the first edge, and semi-cylindrical grooves 12 be formed at corresponding edges opposite to the bolt fixing parts 11 to receive the semi-cylindrical bolt fixing parts 1 1. Accordingly, when the manifold block is installed in a state where a plurality of valve bodies 10 are adjacent to one another, the width of the plurality of valve bodies 10 can be reduced and the entire area occupied by the valve bodies 10 can be reduced. Referring to FIG. 2, the body blocks 10a and 10b of the valve body 10 are joined as one body by inserting bolt members 13 into the body blocks 10a and 10b. To this end, the first body 10a has a screw groove 14a, and the second body block 10b has a bolt through-hole 14b aligned with the screw groove 14a. Seal members 15 are inserted into an interface between the body blocks 10a and 10b, which are coupled to each other by the bolt members 13, as shown in FIGS. 4A and 4B, to prevent fluid leakage. The valve body 10 and the solenoid mechanism 20 are simply coupled to each other as shown in FIG. 3. The valve body 10 includes a frame fixing part 16 formed at a side surface of the first body block 10a, and the solenoid mechanism 20 includes a frame 27 having a bent catching section 27a by which the frame fixing part 16 is caught not to be separated from the solenoid mechanism 20. Referring to FIGS. 4A and 4B, the valve body 10 includes three ports, two formed in the first body block 10a and one formed in the second body block 10b. The three ports are a supply port P, a load port A, and an exhaust port R. The supply port P is connected to an air pump or an accumulator, which is typical pneumatic pressure generating equipment, to receive compressed air therefrom. The load port A is connected to an actuator such as an air cylinder or to a pilot port of other valve to output or collect compressed air. The exhaust port R discharges the compressed air collected by the load port A. The valve body 10 further includes a solenoid operation room 17 opened at a front surface of the first body block 10a, and a valve room 40 formed between the first and second body blocks 10a and 10b. Since the two body blocks 10a and 10b constituting the valve body 10 are designed to be separated using the valve room 4O as a border, each body block can be made of a synthetic resin material through injection molding. A head portion of a plunger 23 of the solenoid mechanism 20 is inserted together with a plunger spring 24 into the solenoid operation room 17 of the first body block 10a. The solenoid mechanism 20 includes a solenoid coil 21 excited by an external electrical signal and producing an electrical thrust, a coil bobbin 22 wound with the solenoid coil, the plunger 23, and the plunger spring 24, a fixed iron core 25, a seal member 26, the aforesaid frame 27, a frame housing 28, and an adapter plate 29. Here, the solenoid coil 21 pulls the plunger 23 toward the coil bobbin 22 with an electrical thrust exceeding the plunger spring 24. The plunger spring 24 is contracted due to the electrical thrust of the solenoid coil 21 and elastically restores the plunger 23 when the electrical thrust is removed. The fixed iron core 25 fixedly inserted into the coil bobbin 22 is spaced apart from the plunger 23 as far as a stroke of the plunger 23, and is wound by the seal member 26. The first body block 10a of the valve body 10 further has a button hole 18 extending from a top surface of the first body block 10a to an end of the solenoid operation room 17, and a pin hole 19 extending from the front surface of the first body block 10a to a middle point of the button hole 18. A push button 30 inserted into the button hole 18 is elastically supported by a button spring 35 to be restored after a push operation, and has a slope portion 31 and a stopper groove 32. The slope portion 31 is adjacent to the head portion of the plunger 23 inside the solenoid operation room 17 to push rearward the plunger 23 during the push operation of the push button 30. A stopper pin 33 inserted into the pin hole 18 of the first body block 10a is also inserted into the stopper groove 32 such that the push button 30 can perform its push operation by a predetermined distance but can be prevented from being separated from the button hole 18. A seal member 34 wound around the push button 30 prevents fluid leakage. The valve room 40 formed between the first and second body blocks 10a and

10b has valve seats 41 and 43 that are formed on facing inner surfaces at front and rear sides and are aligned with each other. The valve room 40 communicates with the supply port P through a valve hole 42 of the valve seat 41 , and communicates with the exhaust port R through a valve hole 44 of the valve seat 43. The valve room 40 also communicates with the load port A directly passing through substantially a middle point of the valve room 40. In FIGS. 4A and 4B, although the load port A is formed in the first body block 10a, it can be formed in the second body block 10b according to a contact position between the first and second body blocks 10a and 10b. Referring to FIG. 5, an interlocking hole 45 connected to the solenoid operation room 17 is formed beside the valve seat 43 at the exhaust port side of the valve room 40. A valve mechanism 50 is inserted together with a valve spring 57 into the valve room 40. Referring to FIG. 6, the valve mechanism 50 includes a valve member 51 and a valve holder 54. The valve member 51 is made of an elastic material such as rubber, and has valve elements 52 and 53 formed at both ends thereof. A distance between the valve elements 52 and 53 formed at both the ends of the valve member 51 is designed to be less than a distance between the valve seats 41 and 43 in the valve room 40 within a range not exceeding the stroke of the plunger 23, such that the valve seat 41 at the supply port side and the valve seat 43 at the exhaust port side of the valve room 40 can be alternately opened and closed. The valve holder 54 is made of a cylindrical synthetic resin material such that the valve member 51 can be fitted into the valve holder 54 and the valve elements 52 and 53 can protrude from both the sides of the valve member 51. The valve holder 54 includes a spring support projection 55 formed on an outer peripheral surface of a body, and an interlocking protrusion 56 extending from one end of the body. Referring to FIG. 5, the interlocking protrusion 56 of the valve mechanism 50 contacts the plunger 23 inserted into the solenoid operation room 17 through the interlocking hole 45. The valve spring 57 supports the valve mechanism 50 in a direction opposite to the plunger spring 24 of the solenoid mechanism 20, and has an elastic force weaker than the elastic force of the plunger spring 24. The three-port solenoid valve according to the present embodiment is repeatedly operated by controlling an electrical signal applied to the solenoid coil 21 of the solenoid mechanism 20. FIG. 4A illustrates a state where no electrical signal is applied to the solenoid coil 21 , and FIG. 4B illustrates a state where an electrical signal is applied to the solenoid coil 21. In a normal state as shown in FIG. 4A, the plunger 23 is moved toward the solenoid operation room 17 due to the elastic force of the plunger spring 24. The valve mechanism 50 having the interlocking protrusion 56 contacting the plunger 23 is pushed by the plunger 23, such that the valve element 52 closely contacts the valve seat 41 at the supply port side of the valve room 40 to block the valve hole 42, and the valve element 53 is separated from the valve seat 43 at the exhaust port side of the valve room 40 to open the valve hole 44. Accordingly, the valve room 40 is blocked from the supply port P, and the load port A and the exhaust port R are opened to the valve room 40. The flow of fluid (compressed air) passing through the valve room 40 is shown by arrow in FIG. 4A. If an electrical signal is applied to the solenoid coil 21 and an electrical thrust is produced, as shown in FIG. 4B, the plunger 23 pushes down the plunger spring 24 and is pulled toward the coil bobbin 22, and the valve mechanism 50 of the valve room 40 is moved due to the elastic force of the valve spring 57 such that the valve element 52 opens the valve hole 42 of the valve seat 41 at the supply port side and the valve element 53 closely contacts the valve seat 43 at the exhaust port side to block the valve hole 44. Accordingly, the valve room 40 is blocked from the exhaust port R, and the supply port P and the load port A are opened to the valve room 40. The flow of fluid (compressed air) passing through the valve room 40 is shown by an arrow in FIG. 4B. The operation of the three-port solenoid valve is repeatedly performed according to the control of an electrical signal applied to the solenoid coil 21 , and of course, the valve returns to its initial state during a power cut. In the meantime, if the push button 30 is pressed in the initial state as shown in FIG. 4A where no electrical signal is applied, the plunger 23 is forced to be pushed by the slope portion 31 of the pressed push button 30, and as a result, the valve is converted into the state as shown in FIG. 4b where an electrical signal is applied. This converted state is maintained while the push button 30 is pressed. If the push button 30 is no longer pressed, the pushed plunger 23 is restored to its initial state by the plunger spring 26. That is, during a power cut, the valve can be operated by manually pressing the push button 30. Although the valve body and the ports formed under the valve body are fixed to the manifold block, the fixing method of the valve body and the ports or the arrangement of the ports can be varied according to applications. Furthermore, although the present embodiment is applied to a pneumatic type of valve, the present invention can be applied both to the pneumatic type of valve and a hydraulic type of valve that is substantially identical in configuration and principle to the pneumatic type of valve. While the present invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims.

Claims

What is claimed is: 1. A three-port solenoid valve comprising: a valve body including a plurality of ports comprised of a supply port, a load port, and an exhaust port through each of which fluid enters and exits, and a valve room through which the plurality of ports pass; a solenoid mechanism coupled to the valve body, driven to produce an electrical thrust using an external electrical signal, and including a plunger moved forward and backward due to the electrical thrust; and a valve mechanism movably accommodated in the valve room of the valve body and interlocking with the plunger of the solenoid mechanism to alternately open and close the supply port and the exhaust port among the ports passing through the valve room.

2. The three-port solenoid valve of claim 1 , wherein the valve body is formed by adhering two body blocks that are separated using the valve room as a border.

3. The three-port solenoid valve of claim 1 , wherein the solenoid mechanism comprises: a solenoid coil excited by an external electrical signal and producing an electrical thrust; a coil bobbin wound with the solenoid coil; the plunger movably inserted into the coil bobbin and pulled due to the electrical thrust of the solenoid coil; and a plunger spring elastically restoring the plunger when the electrical thrust of the solenoid coil is removed.

4. The three-port solenoid valve of claim 1 , wherein the valve mechanism comprises: a valve member made of an elastic material and having valve elements formed at both ends thereof to alternately open and close the supply port and the exhaust port passing through the valve room; a valve holder allowing the valve member to be fitted thereinto and having an interlocking protrusion that passes through an inner wall of the valve room and contacts and interlocks with an end of the plunger of the solenoid mechanism; and a valve spring elastically supporting the valve holder and pushing the valve holder in a direction opposite to the plunger.

5. The three-port solenoid valve of claim 1 , further comprising a push button pushably installed in the valve body and interlocking with the plunger of the solenoid mechanism according to its push operation.

6. The three-port solenoid valve of claim 4, wherein the valve room has valve holes respectively connected to the supply port and the exhaust port, and also has valve seats that can closely contact the valve elements to block the valve holes .