Electromagnetic valve manifold

An electromagnetic valve manifold includes a manifold base including passages, a pilot electromagnetic valve including a valve body mounted on a mounting surface of the manifold base, a gasket arranged between the mounting surface and the valve body, and a check valve. The valve body includes an electromagnetic valve-side pilot fluid discharge passage. The manifold base includes a base-side pilot fluid discharge passage that opens in the mounting surface and communicates with the electromagnetic valve-side pilot fluid discharge passage. The check valve is configured to prevent fluid from flowing from the base-side pilot fluid discharge passage to the electromagnetic valve-side pilot fluid discharge passage. The check valve is integrated with the gasket.

FIELD

The following description relates to an electromagnetic valve manifold.

DESCRIPTION OF RELATED ART

The electromagnetic valve manifold includes a manifold base and a pilot electromagnetic valve having a valve body mounted on a mounting surface of the manifold base. The manifold base includes passages that open in the mounting surface. The valve body of the pilot electromagnetic valve includes ports that respectively communicate with the passages and a valve hole that communicates with the ports and accommodates a valve member. Action of a pilot fluid moves the valve member back and forth in the valve hole, thereby connecting and disconnecting the ports to and from each other.

Japanese Patent No. 3766749 discloses an exemplary electromagnetic valve manifold including a sealing gasket arranged between the mounting surface of the manifold base and the valve body. The gasket is held between the mounting surface of the manifold base and the valve body. The gasket prevents fluid flowing between each passage and corresponding ports from leaking out of the section between the mounting surface of the manifold base and the valve body.

Further, the valve body includes an electromagnetic valve-side pilot fluid discharge passage through which a pilot fluid is discharged. The manifold base includes a base-side pilot fluid discharge passage that opens in the mounting surface and communicates with the electromagnetic valve-side pilot fluid discharge passage.

Japanese Patent No. 3153119 discloses an example of another exemplary electromagnetic valve manifold including a check valve that prevents fluid from flowing from the base-side pilot fluid discharge passage to the electromagnetic valve-side pilot fluid discharge passage. The check valve is held and arranged between the mounting surface of the manifold base and the valve body.

The check valve is a component that is smaller than, for example, the gasket. Thus, in the above-described electromagnetic valve manifold, in which the gasket and the check valve are arranged between the mounting surface of the manifold base and the valve body, during maintenance, for example, when the pilot electromagnetic valve is coupled to or removed from the manifold base, the check valve may fall off. In such a case, the check valve may be lost. Accordingly, the pilot electromagnetic valve cannot be efficiently coupled to or removed from the manifold base.

SUMMARY

It is an object of the present disclosure to provide an electromagnetic valve manifold that improves the working efficiency for coupling and removing a pilot electromagnetic valve to and from a manifold base.

In one general aspect, an electromagnetic valve manifold includes a manifold base including passages and a mounting surface, a pilot electromagnetic valve including a valve body mounted on the mounting surface, a sealing gasket arranged between the mounting surface and the valve body, a check valve. The passages open in the mounting surface. The valve body includes ports that respectively communicate with the passages and a valve hole that communicates with the ports and accommodates a valve member. The valve member is configured to be moved back and forth in the valve hole by an action of a pilot fluid, thereby connecting and disconnecting the ports to and from each other. The valve body includes an electromagnetic valve-side pilot fluid discharge passage through which the pilot fluid is discharged. The manifold base includes a base-side pilot fluid discharge passage that opens in the mounting surface and communicates with the electromagnetic valve-side pilot fluid discharge passage. The check valve is configured to prevent fluid from flowing from the base-side pilot fluid discharge passage to the electromagnetic valve-side pilot fluid discharge passage. The check valve is integrated with the gasket.

DETAILED DESCRIPTION

An electromagnetic valve manifold10according to an embodiment will now be described with reference toFIGS. 1 to 4.

As shown inFIG. 1, the electromagnetic valve manifold10includes a quadrilateral block-shaped manifold base11and a pilot electromagnetic valve12. The pilot electromagnetic valve12includes an elongated quadrilateral block-shaped valve body13mounted on a mounting surface11aof the manifold base11.

The valve body13includes an elongated quadrilateral block-shaped body member14, a first coupled block15coupled to the first end of the body member14in a longitudinal direction, and a second coupled block16coupled to the second end of the body member14in the longitudinal direction. The body member14, the first coupled block15, and the second coupled block16are made of, for example, synthetic plastic. The body member14includes a body opposing surface14aopposed to the mounting surface11a.The first coupled block15includes a first opposing surface15aopposed to the mounting surface11a.The second coupled block16includes a second opposing surface16aopposed to the mounting surface11a.

The body member14includes a circular valve hole18that accommodates a valve member17. The valve hole18extends in the longitudinal direction of the body member14. The first end of the valve hole18opens in a first end surface of the body member14in the longitudinal direction, and the second end of the valve hole18opens in a second end surface of the body member14in the longitudinal direction. Thus, the valve hole18extends through the body member14in the longitudinal direction. The valve member17is a spool valve member accommodated in the valve hole18such that the valve member17is movable back and forth in the valve hole18.

The body member14includes a supply port20, a first output port21, a second output port22, a first discharge port23, and a second discharge port24. The supply port20, the first output port21, the second output port22, the first discharge port23, and the second discharge port24are ports formed in the valve body13. The pilot electromagnetic valve12of the present embodiment is a five-port electromagnetic valve.

The five ports20to24are arranged in the order of the first discharge port23, the first output port21, the supply port20, the second output port22, and the second discharge port24from the first end to the second end of the body member14in the longitudinal direction. The first end of each of the ports20to24communicates with the valve hole18. The second end of each of the ports20to24opens in the body opposing surface14aof the body member14.

The inner circumferential surface of the valve hole18includes a first valve seat25located between the supply port20and the first output port21, a second valve seat26located between the first output port21and the first discharge port23, a third valve seat27located between the supply port20and the second output port22, and a fourth valve seat28located between the second output port22and the second discharge port24. The first valve seat25, the second valve seat26, the third valve seat27, and the fourth valve seat28have an annular shape and configure part of the inner circumferential surface of the valve hole18.

The valve hole18includes a first hole portion18aconfiguring the first end of the valve hole18. The first hole portion18acommunicates with the first discharge port23and is located on the opposite side from the first discharge port23from the second valve seat26. The valve hole18includes a second hole portion18bconfiguring the second end of the valve hole18. The second hole portion18bcommunicates with the second discharge port24and is located on the opposite side from the second discharge port24from the fourth valve seat28. The first valve seat25, the second valve seat26, the third valve seat27, the fourth valve seat28, the first hole portion18a,and the second hole portion18bhave the same inner diameter.

The valve member17includes a first valve part171, a second valve part172, a third valve part173, a fourth valve part174, a fifth valve part175, and a sixth valve part176, which are spaced away from one another in an axial direction of the valve member17. The first to sixth valve parts171to176are arranged in the order of the fifth valve part175, the second valve part172, the first valve part171, the third valve part173, the fourth valve part174, and the sixth valve part176from the first end to the second end of the valve member17in the axial direction. The first to sixth valve parts171to176have the same diameter.

The valve member17includes a first shaft17athat couples the first valve part171and the third valve part173to each other, a second shaft17bthat couples the first valve part171and the second valve part172to each other, and a third shaft17cthat couples the third valve part173and the fourth valve part174to each other. Further, the valve member17includes a fourth shaft17dthat couples the second valve part172and the fifth valve part175to each other and a fifth shaft17ethat couples the fourth valve part174and the sixth valve part176to each other.

The valve member17includes a columnar first protrusion17fprotruding from the end surface of the fifth valve part175on the opposite of the fourth shaft17d.The first protrusion17fis the first end of the valve member17in the axial direction. Further, the valve member17includes a columnar second protrusion17gprotruding from the end surface of the sixth valve part176on the opposite of the fifth shaft17e.The second protrusion17gis the second end of the valve member17in the axial direction.

The first to fifth shafts17ato17e,the first protrusion17f,and the second protrusion17ghave the same outer diameter. The outer diameter of the first to sixth valve parts171to176is larger than the outer diameter of the first to fifth shafts17ato17e,the first protrusion17f,and the second protrusion17g.

The outer circumferential surface of the first valve part171is provided with a first spool packing291that seals the section between the supply port20and the first output port21when the first valve part171rests on the first valve seat25. The outer circumferential surface of the second valve part172is provided with a second spool packing292that seals the section between the first output port21and the first discharge port23when the second valve part172rests on the second valve seat26. The outer circumferential surface of the third valve part173is provided with a third spool packing293that seals the section between the supply port20and the second output port22when the third valve part173rests on the third valve seat27. The outer circumferential surface of the fourth valve part174is provided with a fourth spool packing294that seals the section between the second output port22and the second discharge port24when the fourth valve part174rests on the fourth valve seat28. The first to fourth spool packings291to294have an annular shape and are made of rubber.

The first coupled block15includes a circular first piston accommodation recess31that communicates with the first hole portion18a.The first protrusion17fof the valve member17is movable such that the first protrusion17fmoves from the first hole portion18ainto the first piston accommodation recess31and moves from the first piston accommodation recess31back into the first hole portion18a.The first piston accommodation recess31accommodates a circular first piston32such that the first piston32is movable back and forth. The first piston32is coupled to the first protrusion17f,which is the first end of the valve member17. The outer circumferential surface of the first piston32is provided with a first lip packing33. The first lip packing33seals the section between the first piston32and the inner circumferential surface of the first piston accommodation recess31. The first piston32defines a first pilot pressure acting chamber34in the first piston accommodation recess31. A pilot fluid is supplied to and discharged out of the first pilot pressure acting chamber34.

The second coupled block16includes a circular second piston accommodation recess35that communicates with the second hole portion18b.The second piston accommodation recess35has a smaller inner diameter than the first piston accommodation recess31. The second protrusion17gof the valve member17is movable such that the second protrusion17gmoves from the second hole portion18binto the second piston accommodation recess35and moves from the second piston accommodation recess35back into the second hole portion18b.The second piston accommodation recess35accommodates a circular second piston36such that the second piston36is movable back and forth. The second piston36is coupled to the second protrusion17g,which is the second end of the valve member17. The second piston36has a smaller outer diameter than the first piston32. The outer circumferential surface of the second piston36is provided with a second lip packing37. The second lip packing37seals the section between the second piston36and the inner circumferential surface of the second piston accommodation recess35. The second piston36defines a second pilot pressure acting chamber38in the second piston accommodation recess35. A pilot fluid is supplied to and discharged out of the second pilot pressure acting chamber38.

The outer diameter of the second piston36is smaller than the outer diameter of the first piston32. Thus, the pressure-receiving area of the second piston36, that is, the area of where the second piston36receives the pressure of a pilot fluid in the second pilot pressure acting chamber38is smaller than the pressure-receiving area of the first piston32, that is, the area of where the first piston32receives the pressure of a pilot fluid in the first pilot pressure acting chamber34.

The outer circumferential surface of the fifth valve part175is provided with a first seal member39athat seals the section between the fifth valve part175and the first hole portion18a.The first seal member39ahas an annular shape and is made of rubber. The first seal member39arestricts fluid from leaking from the first discharge port23through the first hole portion18ato the first piston accommodation recess31.

The outer circumferential surface of the sixth valve part176is provided with a second seal member39bthat seals the section between the sixth valve part176and the second hole portion18b.The second seal member39bhas an annular shape and is made of rubber. The second seal member39brestricts fluid from leaking from the second discharge port24through the second hole portion18bto the second piston accommodation recess35.

The pilot electromagnetic valve12includes a pilot valve part40. The pilot electromagnetic valve12of the present embodiment is of a single pilot type, that is, a single pilot valve part40is provided. The pilot valve part40includes a solenoid part41. The pilot valve part40is coupled to the end of the first coupled block15on the opposite side from the body member14.

Further, the valve body13includes a pilot fluid supply passage42that communicates with the supply port20through the valve hole18. The pilot fluid supply passage42opens at a position of the valve member17that constantly communicates with the supply port20regardless of the position of the valve member17. The pilot fluid supply passage42branches halfway to be connected to the pilot valve part40and the second pilot pressure acting chamber38.

The first coupled block15includes a pilot fluid output passage43that connects the pilot valve part40and the first pilot pressure acting chamber34to each other. Further, the first coupled block15includes a pilot fluid discharge passage44through which a pilot fluid is discharged. The first end of the pilot fluid discharge passage44is connected to the pilot valve part40, and the second end of the pilot fluid discharge passage44opens in the first opposing surface15aof the first coupled block15.

The manifold base11includes a supply passage50, a first output passage51, a second output passage52, a first discharge passage53, and a second discharge passage54. The supply passage50, the first output passage51, the second output passage52, the first discharge passage53, and the second discharge passage54are passages formed in the manifold base11.

The five passages50to54open in the mounting surface11a.The supply passage50includes a first end that opens in the mounting surface11aand communicates with the supply port20. The first output passage51includes a first end that opens in the mounting surface11aand communicates with the first output port21. The second output passage521includes a first end that opens in the mounting surface11aand communicates with the second output port22. The first discharge passage53includes a first end that opens in the mounting surface11aand communicates with the first discharge port23. The second discharge passage54includes a first end that opens in the mounting surface11aand communicates with the second discharge passage54.

The supply passage50includes a second end connected to a fluid supply source (not shown) by a pipe or the like. Each of the first output passage51and the second output passage52includes a second end connected to a fluid pressure device (not shown) by a pipe or the like. Each of the first discharge passage53and the second discharge passage54includes a second end connected to the atmosphere by a pipe or the like.

Additionally, the manifold base11includes a first base-side pilot fluid discharge passage55and a second base-side pilot fluid discharge passage56. Thus, in the present embodiment, the manifold base11includes two base-side pilot fluid discharge passages.

The first end of the first base-side pilot fluid discharge passage55opens in a portion of the mounting surface11aopposed to the first opposing surface15aof the first coupled block15and communicates with the electromagnetic valve-side pilot fluid discharge passage44. The second end of the first base-side pilot fluid discharge passage55communicates with the first discharge passage53. The first end of the second base-side pilot fluid discharge passage56opens in a portion of the mounting surface11aopposed to the second opposing surface16aof the second coupled block16. The second end of the second base-side pilot fluid discharge passage56communicates with the second discharge passage54.

Fluid from the fluid supply source is constantly supplied to the second pilot pressure acting chamber38through the supply passage50, the supply port20, and the pilot fluid supply passage42and serves as a pilot fluid.

When the solenoid part41is supplied with power, the pilot valve part40causes the pilot fluid supply passage42and the pilot fluid output passage43to communicate with each other and disconnects the pilot fluid output passage43from the electromagnetic valve-side pilot fluid discharge passage44. As a result, fluid from the fluid supply source is supplied to the first pilot pressure acting chamber34through the supply passage50, the supply port20, the pilot fluid supply passage42, and the pilot fluid output passage43and serves as a pilot fluid.

The pressure-receiving area of the second piston36receiving a pilot fluid in the second pilot pressure acting chamber38is smaller than the pressure-receiving area of the first piston32receiving a pilot fluid in the first pilot pressure acting chamber34. Thus, the valve member17moves toward the second piston accommodation recess35. As a result, the supply port20and the first output port21communicate with each other, and the second output port22and the second discharge port24communicate with each other. Further, the section between the supply port20and the second output port22is sealed by the third spool packing293of the third valve part173, and the section between the first output port21and the first discharge port23is sealed by the second spool packing292of the second valve part172.

The fluid from the fluid supply source is supplied to the fluid pressure device through the supply passage50, the supply port20, the first output port21, and the first output passage51. Further, the fluid from the fluid pressure device is discharged to the atmosphere through the second output passage52, the second output port22, the second discharge port24, and the second discharge passage54.

When the supplying of power to the solenoid part41is stopped, the pilot valve part40causes the pilot fluid output passage43and the electromagnetic valve-side pilot fluid discharge passage44to communicate with each other and disconnects the pilot fluid supply passage42from the pilot fluid output passage43. This stops supplying the fluid from the fluid supply source to the first pilot pressure acting chamber34through the supply passage50, the supply port20, the pilot fluid supply passage42, and the pilot fluid output passage43. The fluid in the first pilot pressure acting chamber34is discharged to the atmosphere through the pilot fluid output passage43, the pilot fluid discharge passage44, the first base-side pilot fluid discharge passage55, and the first discharge passage53. This moves the valve member17toward the first piston accommodation recess31. As a result, the supply port20and the second output port22communicate with each other, and the first output port21and the first discharge port23communicate with each other. Further, the section between the supply port20and the first output port21is sealed by the first spool packing291of the first valve part171, and the section between the second output port22and the second discharge port24is sealed by the fourth spool packing294of the fourth valve part174.

The fluid from the fluid supply source is supplied to the fluid pressure device through the supply passage50, the supply port20, the second output port22, and the second output passage52. Further, the fluid from the fluid pressure device is discharged to the atmosphere through the first output passage51, the first output port21, the first discharge port23, and the first discharge passage53.

Accordingly, the pilot electromagnetic valve12of the present embodiment is of an internal pilot type, in which part of fluid that has been supplied to the supply port20is supplied to the first pilot pressure acting chamber34and the second pilot pressure acting chamber38. Action of a pilot fluid moves the valve member17back and forth in the valve hole18, thereby connecting and disconnecting the ports to and from each other.

The electromagnetic valve manifold10includes a gasket60that seals the section between the mounting surface11aand the valve body13. The gasket60is arranged between the mounting surface11aand the valve body13. Further, the electromagnetic valve manifold10includes a first check valve71that prevents fluid from flowing from the first base-side pilot fluid discharge passage55to the electromagnetic valve-side pilot fluid discharge passage44. In addition, the electromagnetic valve manifold10includes a second check valve72, which is used when the pilot electromagnetic valve12is of a double pilot type, that is, when the pilot electromagnetic valve12has two pilot valve parts40.

As shown inFIG. 2, the gasket60includes a metal plate61and two seal members62joined to the metal plate61and made of rubber. The seal members62are respectively joined to the opposite surfaces of the metal plate61.

The metal plate61is an elongated flat plate. The metal plate61includes a first communication hole61a,a second communication hole61b,a third communication hole61c,a fourth communication hole61d,and a fifth communication hole61e.The first to fifth communication holes61ato61eare arranged in the longitudinal direction of the metal plate61and extend through the metal plate61in the thickness direction. The first communication hole61aconnects the supply port20and the supply passage50with each other. The second communication hole61bconnects the first output port21and the first output passage51with each other. The third communication hole61cconnects the second output port22and the second output passage52with each other. The fourth communication hole61dconnects the first discharge port23and the first discharge passage53with each other. The fifth communication hole61econnects the second discharge port24and the second discharge passage54with each other.

Each seal member62is joined to one of the opposite surfaces of the metal plate61so as to surround the first communication hole61a,the second communication hole61b,the third communication hole61c,the fourth communication hole61d,and the fifth communication hole61eone by one.

The surface of the opposite surfaces of the metal plate61opposed to the body opposing surface14aof the body member14is provided with two positioning protrusions63. The positioning protrusions63are respectively arranged at two diagonally-located corners of the four corners of the metal plate61.

The metal plate61includes two screw insertion holes61h.Each screw insertion hole61hextends through the metal plate61in the thickness direction. Each screw insertion hole61his arranged at a position adjacent to the corresponding positioning protrusion63in the longitudinal direction of the metal plate61.

The metal plate61includes a first coupling portion64and a second coupling portion65. The first coupling portion64has a flat shape and protrudes from a first side edge611, which is one of the opposite edges of the metal plate61in the longitudinal direction. The second coupling portion65has a flat shape and protrudes from a second side edge612, which is the other one of the opposite edges of the metal plate61in the longitudinal direction. The first coupling portion64and the second coupling portion65respectively extend from the side edges611and612in a direction in which the first coupling portion64and the second coupling portion65are spaced apart from each other in the longitudinal direction of the metal plate61.

As shown inFIG. 3, the first coupling portion64includes an insertion hole64h.The insertion hole64hhas a circular shape and extends through the first coupling portion64in the thickness direction. A rubber elastic portion64ais joined to the inner circumferential surface of the insertion hole64h.The elastic portion64ahas an annular shape and covers the entire inner circumferential surface of the insertion hole64h.The first coupling portion64includes a first surface opposed to the mounting surface11a.A rubber seal part64bis joined to the surrounding part of the insertion hole64hin the first surface of the first coupling portion64. The seal part64bis annular. The inner circumferential edge of the seal part64bis continuous with the elastic portion64a.The elastic portion64aextends in the axial direction from the inner circumferential edge of the seal part64b.The elastic portion64aand the seal part64bare formed integrally with each other.

The second coupling portion65includes an insertion hole65h.The insertion hole65hhas a circular shape and extends through the second coupling portion65in the thickness direction. A rubber elastic portion65ais joined to the inner circumferential surface of the insertion hole65h.The elastic portion65ahas an annular shape and covers the entire inner circumferential surface of the insertion hole65h.The second coupling portion65includes a first surface opposed to the mounting surface11a.A rubber seal part65bis joined to the surrounding part of the insertion hole65hin the first surface of the second coupling portion65. The seal part65bis annular. The inner circumferential edge of the seal part65bis continuous with the elastic portion65a.The elastic portion65aextends in the axial direction from the inner circumferential edge of the seal part65b.The elastic portion65aand the seal part65bare formed integrally with each other.

The first check valve71is of a duckbill type including a circumferential wall71a, a beak part71b, and a flange71c. The circumferential wall71ahas a cylindrical shape. The beak part71bis continuous with the first end of the circumferential wall71ain the axial direction. Also, the beak part71btapers as the beak part71bbecomes farther from the circumferential wall71a. The flange71c, which is annular, is continuous with the outer circumferential edge of the second end of the circumferential wall71ain the axial direction and extends radially outward from the outer circumferential edge of the second end of the circumferential wall71a. The distal end of the beak part71bis provided with a slit71dthat allows the inside and outside of the beak part71bto communicate with each other.

The first check valve71is coupled to the first coupling portion64with the circumferential wall71ainserted through the insertion hole64hof the first coupling portion64. The first coupling portion64includes a second surface opposed to the first opposing surface15a.The flange71cis in close contact with the surrounding part of the insertion hole64hin the second surface of the first coupling portion64. The portion corresponding to the first end of the circumferential wall71aprotrudes from the seal part64bthrough the insertion hole64h.

Thus, part of the first check valve71is inserted through the insertion hole64h,and the first check valve71is inserted through the insertion hole64hand coupled to the first coupling portion64. Inserting the circumferential wall71athrough the insertion hole64helastically deforms the elastic portion64ato be crushed between the inner circumferential surface of the insertion hole64hand the circumferential wall71a.Thus, the elastic portion64ais arranged between the inner circumferential surface of the insertion hole64hand the first check valve71. A restoring force that restores the elastic portion64ato its original shape prior to being elastically deformed is applied to fasten the first check valve71to the inner circumferential surface of the insertion hole64hwith the elastic portion64alocated in between. Thus, the first check valve71, which is separate from the gasket60, is fixed to and integrated with the gasket60.

The second check valve72is of a duckbill type including a circumferential wall72a, a beak part72b, and a flange72c. The circumferential wall72ahas a cylindrical shape. The beak part72bis continuous with the first end of the circumferential wall72ain the axial direction. Also, the beak part72btapers as the beak part72bbecomes farther from the circumferential wall72a. The flange72c, which is annular, is continuous with the outer circumferential edge of the second end of the circumferential wall72ain the axial direction and extends radially outward from the outer circumferential edge of the second end of the circumferential wall72a. The distal end of the beak part72bis provided with a slit72dthat allows the inside and outside of the beak part72bto communicate with each other.

The second check valve72is coupled to the second coupling portion65with the circumferential wall72ainserted through the insertion hole65hof the second coupling portion65. The second coupling portion65includes a second surface opposed to the second opposing surface16a.The flange72cis in close contact with the surrounding part of the insertion hole65hin the second surface of the second coupling portion65. The portion corresponding to the first end of the circumferential wall72aprotrudes from the seal part65bthrough the insertion hole65h.

Thus, part of the second check valve72is inserted through the insertion hole65h,and the second check valve72is inserted through the insertion hole65hand coupled to the second coupling portion65. Inserting the circumferential wall72athrough the insertion hole65helastically deforms the elastic portion65ato be crushed between the inner circumferential surface of the insertion hole65hand the circumferential wall72a.Thus, the elastic portion65ais arranged between the inner circumferential surface of the insertion hole65hand the second check valve72. A restoring force that restores the elastic portion65ato its original shape prior to being elastically deformed is applied to fasten the second check valve72to the inner circumferential surface of the insertion hole65hwith the elastic portion65alocated in between. Thus, the second check valve72, which is separate from the gasket60, is fixed to and integrated with the gasket60. Accordingly, in the present embodiment, two check valves are fixed to and integrated with the gasket60. The term “integrate” refers to fixing (or fitting) the check valves71and72, which are separate from the gasket60, to the gasket60, and integrally forming the check valves71and72with the gasket60.

As shown inFIG. 4, the first opposing surface15aof the first coupled block15includes a circular fixing recess15cinto which the flange71cof the first check valve71is fitted. The inner space of the fixing recess15ccommunicates with the electromagnetic valve-side pilot fluid discharge passage44. The electromagnetic valve-side pilot fluid discharge passage44opens in the bottom surface of the fixing recess15c,which configures part of the first opposing surface15a.When the flange71cof the first check valve71is fitted into the fixing recess15c,the electromagnetic valve-side pilot fluid discharge passage44and the inner space of the first check valve71communicate with each other.

The flange71cof the first check valve71is held between the bottom surface of the fixing recess15cand the second surface of the first coupling portion64around the insertion hole64h.The flange71cseals the section between the bottom surface of the fixing recess15cand the second surface of the first coupling portion64around the insertion hole64h.The seal part64bis held between the first surface of the first coupling portion64and the mounting surface11aaround the insertion hole64h.The seal part64bseals the section between the first surface of the first coupling portion64and the mounting surface11aaround the insertion hole64h.

The second opposing surface16aof the second coupled block16includes a circular fixing recess16cinto which the flange72cof the second check valve72is fitted. The flange72cof the second check valve72is held between the bottom surface of the fixing recess16cand the second surface of the second coupling portion65around the insertion hole65h.The flange72cseals the section between the bottom surface of the fixing recess16cand the second surface of the second coupling portion65around the insertion hole65h.The seal part65bis held between the first surface of the second coupling portion65and the mounting surface11aaround the insertion hole65h.The seal part65bseals the section between the first surface of the second coupling portion65and the mounting surface11aaround the insertion hole65h.

The body opposing surface14aof the body member14has an insertion recess14binto which each positioning protrusion63is inserted. The insertion recesses14bare respectively arranged at two diagonally-located corners of the four corners of the body opposing surface14a.Further, the body member14includes two screw insertion holes14h.Each screw insertion hole14his arranged at a position adjacent to the corresponding insertion recess14bin the longitudinal direction of the body member14.

As shown inFIG. 2, the mounting surface11ahas two internal threaded holes11h.A screw19is screwed through each screw insertion hole14hof the body member14and each screw insertion hole61hof the gasket60into each internal threaded hole11h.This holds the gasket60between the mounting surface11aand the valve body13and couples the pilot electromagnetic valve12to the mounting surface11a.

The first base-side pilot fluid discharge passage55includes an opening55athat opens in the mounting surface11a,and the second base-side pilot fluid discharge passage56includes an opening56athat opens in the mounting surface11a.In a state in which the pilot electromagnetic valve12is coupled to the manifold base11, the circumferential wall71aof the first check valve71is fitted into the opening55aof the first base-side pilot fluid discharge passage55, and the circumferential wall72aof the second check valve72is fitted into the opening56aof the second base-side pilot fluid discharge passage56. The two openings55aand56aare circular. The outer diameter of each of the circumferential walls71aand72ais slightly smaller than the inner diameter of the corresponding one of the openings55aand56a.Each of the circumferential walls71aand72ais firmly fitted into the corresponding one of the openings55aand56a.

In this manner, the circumferential wall71aof the first check valve71is a fitted portion fitted into the opening55aof the first base-side pilot fluid discharge passage55. Thus, the first check valve71includes a fitted portion fitted into the opening55aof the first base-side pilot fluid discharge passage55. The circumferential wall72aof the second check valve72is a fitted portion fitted into the opening56aof the second base-side pilot fluid discharge passage56. Thus, the second check valve72includes a fitted portion fitted into the opening56aof the second base-side pilot fluid discharge passage56.

When the pressure in the first check valve71reaches a predetermined pressure, the slit71dof the first check valve71opens. Then, the first check valve71allows fluid to flow from the electromagnetic valve-side pilot fluid discharge passage44toward the first base-side pilot fluid discharge passage55. This causes the fluid that has flowed from the electromagnetic valve-side pilot fluid discharge passage44into the first check valve71to flow through the first check valve71to the first base-side pilot fluid discharge passage55. When the pressure in the first check valve71is less than the predetermined pressure, the slit71dcloses. Then, the first check valve71prevents fluid from flowing from the first base-side pilot fluid discharge passage55to the electromagnetic valve-side pilot fluid discharge passage44.

The above-described embodiment has the following advantages.

(1) The first check valve71and the second check valve72are integrated with the gasket60. Thus, for example, during maintenance, when the pilot electromagnetic valve12is coupled to or removed from the manifold base11, the first check valve71or the second check valve72does not fall off separately. Accordingly, when the pilot electromagnetic valve12is coupled to or removed from the manifold base11, the first check valve71or the second check valve72is prevented from being lost. This improves the working efficiency for coupling and removing the pilot electromagnetic valve12to and from the manifold base11.

(2) The circumferential wall71aof the first check valve71is fitted into the opening55aof the first base-side pilot fluid discharge passage55, which opens in the mounting surface11a.This improves the position accuracy of the first check valve71relative to the first base-side pilot fluid discharge passage55. In addition, the circumferential wall72aof the second check valve72is fitted into the opening56aof the second base-side pilot fluid discharge passage56, which opens in the mounting surface11a.This improves the position accuracy of the second check valve72relative to the second base-side pilot fluid discharge passage56. Thus, the working efficiency for coupling the pilot electromagnetic valve12to the manifold base11is improved.

(3) The manifold base11includes two base-side pilot fluid discharge passages, that is, the first base-side pilot fluid discharge passage55and the second base-side pilot fluid discharge passage56. Two check valves, that is, the first check valve71and the second check valve72, are integrated with the gasket60. In this structure, the circumferential wall71aof the first check valve71and the circumferential wall72aof the second check valve72are respectively fitted into the opening55aof the first base-side pilot fluid discharge passage55and the opening56aof the second base-side pilot fluid discharge passage56. This improves the position accuracy of the gasket60relative to the mounting surface11a.Thus, the working efficiency for coupling the pilot electromagnetic valve12to the manifold base11is improved.

(4) The gasket60includes the metal plate61and the seal member62, which is joined to the metal plate61and made of rubber. The metal plate61includes the first coupling portion64, which includes the insertion hole64hthrough which part of the first check valve71is inserted, and the second coupling portion65, which includes the insertion hole65hthrough which part of the second check valve72is inserted. The first check valve71is inserted through the insertion hole64hand coupled to the insertion hole64h,and the second check valve72is inserted through the insertion hole65hand coupled to the second coupling portion65. In this structure, part of the first check valve71is inserted through the insertion hole64hof the first coupling portion64and coupled to the first coupling portion64so that the first check valve71, which is separate from the gasket60, is integrated with the gasket60. Further, part of the second check valve72is inserted through the insertion hole65hof the second coupling portion65and coupled to the second coupling portion65so that the second check valve72, which is separate from the gasket60, is integrated with the gasket60. In this manner, the first check valve71and the second check valve72are integrated with the gasket60. Thus, as compared to when, for example, the first check valve71and the second check valve72are formed integrally with the seal member62of the gasket60, the first check valve71, the second check valve72, and the gasket60are easily manufactured.

(5) The elastic portion64ais arranged between the inner circumferential surface of the insertion hole64hof the first coupling portion64and the first check valve71, and the elastic portion65ais arranged between the inner circumferential surface of the insertion hole65hof the second coupling portion65and the second check valve72. In this structure, inserting part of the first check valve71through the insertion hole64helastically deforms the elastic portion64ato be crushed between the inner circumferential surface of the insertion hole64hand the first check valve71. A restoring force that restores the elastic portion64ato its original shape prior to being elastically deformed is applied to fasten the first check valve71to the inner circumferential surface of the insertion hole64hwith the elastic portion64alocated in between. Further, in this structure, inserting part of the second check valve72through the insertion hole65helastically deforms the elastic portion65ato be crushed between the inner circumferential surface of the insertion hole65hand the second check valve72. A restoring force that restores the elastic portion65ato its original shape prior to being elastically deformed is applied to fasten the second check valve72to the inner circumferential surface of the insertion hole65hwith the elastic portion65alocated in between. This limits the separation of the first check valve71from the insertion hole64hand the separation of the second check valve72from the insertion hole65h.Further, this allows the first check valve71and the second check valve72to be strongly coupled to the first coupling portion64and the second coupling portion65, respectively.

(6) Fitting the flange71cof the first check valve71into the fixing recess15cimproves the position accuracy of the first check valve71relative to the valve body13. Further, fitting the flange72cof the second check valve72into the fixing recess16cimproves the position accuracy of the second check valve72relative to the valve body13. This improves the working efficiency for coupling the pilot electromagnetic valve12to the manifold base11.

(7) Inserting each positioning protrusion63into the corresponding insertion recess14bimproves the position accuracy of the gasket60relative to the valve body13. This improves the working efficiency for coupling the pilot electromagnetic valve12to the manifold base11.

For example, the second check valve72does not have to be integrated with the gasket60, and only the first check valve71may be integrated with the gasket60.

The pilot electromagnetic valve12does not have to include the second check valve72. In this structure, the manifold base11does not have to include the second base-side pilot fluid discharge passage56and may include only the first base-side pilot fluid discharge passage55. Accordingly, the manifold base11may include a single base-side pilot fluid discharge passage.

For example, the first check valve71may be formed integrally with the seal member62of the gasket60. Further, the second check valve72may be formed integrally with the seal member62of the gasket60.

The elastic portion64adoes not have to be arranged between the inner circumferential surface of the insertion hole64hof the first coupling portion64and the first check valve71, and the elastic portion65adoes not have to be arranged between the inner circumferential surface of the insertion hole65hof the second coupling portion65and the second check valve72.

For example, the mounting surface11amay include a clearance recess corresponding to each of the first check valve71and the second check valve72such that the mounting surface11adoes not interfere with the first check valve71and the second check valve72. Each of the first base-side pilot fluid discharge passage55and the second base-side pilot fluid discharge passage56may open in the bottom surface of the corresponding clearance recess. Additionally, for example, the distal end of the beak part71bof the first check valve71and the distal end of the beak part72bof the second check valve72may each be located in the corresponding clearance recess. That is, the circumferential wall71aof the first check valve71does not have to be fitted into the opening55aof the first base-side pilot fluid discharge passage55, and the circumferential wall72aof the second check valve72is fitted into the opening56aof the second base-side pilot fluid discharge passage56.

The gasket60does not have to include the metal plate61and may be configured only by, for example, a plate-shaped rubber seal member.

The elastic portions64aand65amay have an annular shape covering only part of the inner circumferential surfaces of the insertion hole64hand65h.That is, the elastic portions64aand65ado not have to have an endless annular shape.

The elastic portions64aand65ado not have to be continuous with the seal parts64band65b.

The elastic portions64aand65ado not have to be formed integrally with the seal parts64band65band may be separate from the elastic portions64aand65a.

The first check valve71and the second check valve72do not have to be of a duckbill type and may be of an umbrella type. In short, as long as the first check valve71and the second check valve72can be integrated with the gasket60, the shapes of the first check valve71and the second check valve72are not particularly limited.

The first piston32and the second piston36may have the same diameter, and a biasing spring that biases the valve member17toward the first piston accommodation recess31may be accommodated in the second piston accommodation recess35. For example, the pressure in the first pilot pressure acting chamber34may resist the biasing force of the biasing spring to move the valve member17toward the second piston accommodation recess35.

The pilot electromagnetic valve12may be of an external pilot type in which fluid is supplied to the first pilot pressure acting chamber34and the second pilot pressure acting chamber38from the outside of the pilot electromagnetic valve12, instead of the supply port20.

The pilot electromagnetic valve12may be of a double pilot type including two pilot valve parts40.

The pilot electromagnetic valve12may be of, for example, a three-port electromagnetic valve. Thus, the number of ports formed in the valve body13may be changed, and the number of passages formed in the manifold base11may be changed in correspondence with the number of ports formed in the valve body13.