阅读说明：本技术 增压器 (Pressure booster ) 是由 浅叶毅 于 2020-05-14 设计创作，主要内容包括：一种增压器(10),该增压器(10)设置有能够与第一活塞(42)和第二活塞(46)交替接触的先导切换阀(78)。先导切换阀包括插入固定阀元件(80)内部的可移动阀元件(88)和插入可移动阀元件内部的先导阀元件(100),并且设置有与可移动阀元件的一端相邻的第一先导室(96)和与可移动阀元件的另一端相邻的第二先导室(98)。(A supercharger (10) is provided with a pilot switching valve (78) that can alternately contact a first piston (42) and a second piston (46). The pilot switching valve includes a movable valve element (88) inserted inside a fixed valve element (80) and a pilot valve element (100) inserted inside the movable valve element, and is provided with a first pilot chamber (96) adjacent to one end of the movable valve element and a second pilot chamber (98) adjacent to the other end of the movable valve element.)

1. A supercharger, comprising:

a first cylinder portion (18), the first cylinder portion (18) being disposed on one side of the center housing (12);

a second cylinder portion (20), the second cylinder portion (20) being disposed on the other side of the center housing;

a first piston (42) in the first cylinder portion and a second piston (46) in the second cylinder portion, the first piston (42) and the second piston (46) being interconnected and configured to increase a pressure of a compressible fluid supplied to a supply port (22) from a primary pressure to a secondary pressure and output the compressible fluid from an output port (24) by a reciprocating motion; and

a pilot switching valve (78), the pilot switching valve (78) being configured to alternately contact the first piston and the second piston, the pilot switching valve including a movable valve element (88) inserted inside a fixed valve element (80) and a pilot valve element (100) inserted inside the movable valve element, the pilot switching valve being provided with a first pilot chamber (96) disposed adjacent to one end of the movable valve element and a second pilot chamber (98) disposed adjacent to the other end of the movable valve element.

2. The supercharger of claim 1, wherein:

one end portion and the other end portion of the movable valve element protrude from the fixed valve element; and is

One or both of one end portion and the other end portion of the pilot valve member protrude from the movable valve member.

3. The supercharger of claim 1, wherein:

a compressible fluid at the primary pressure is supplied to the second pilot chamber; and is

The compressible fluid at the primary pressure is supplied to the first pilot chamber through the second pilot chamber depending on the position of the movable valve element relative to the fixed valve element and the position of the pilot valve element relative to the movable valve element.

4. The supercharger according to claim 3, wherein the path of the compressible fluid from the second pilot chamber to the first pilot chamber comprises at least a radial hole (90d, 90e, 90f) in the movable valve element, a radial hole (112a, 112b, 112c) in the pilot valve element, and a shaft hole (106) in the pilot valve element.

5. The supercharger of claim 1, wherein an area through which the pressure of the compressible fluid in the first pilot chamber acts on the movable valve element is greater than an area through which the pressure of the compressible fluid in the second pilot chamber acts on the movable valve element.

6. The supercharger of claim 1, wherein the first pilot chamber is connected to an exhaust port (26) depending on the position of the movable valve element relative to the fixed valve element and the position of the pilot valve element relative to the movable valve element.

7. The supercharger of claim 6, wherein the path of the compressible fluid from the first pilot chamber to the exhaust port comprises at least a radial hole in the movable valve element, a radial hole in the pilot valve element, and a shaft hole in the pilot valve element.

8. The supercharger of claim 1, wherein the movable valve element is movable between a position where the movable valve element is in contact with a first insert plate (82a) disposed between the center housing and the first cylinder portion and a position where the movable valve element is in contact with a second insert plate (82b) disposed between the center housing and the second cylinder portion.

9. The supercharger of claim 1, wherein:

a piston portion (104) attached to the pilot valve element is slidably disposed in a cylinder portion (92g) formed in the movable valve element; and is

The cylinder portion is divided by the piston portion into a piston left chamber (108) and a piston right chamber (110).

10. The supercharger of claim 9, wherein:

the piston right chamber is communicated with the discharge port; and is

The piston left chamber communicates with a shaft bore in the pilot valve element.

11. The supercharger of claim 9, wherein:

the movable valve element comprises a first valve portion (90) and a second valve portion (92); and is

The pilot valve element is movable relative to the movable valve element between a position where the plunger portion is in contact with an end of the first valve portion and a position where the plunger portion is in contact with a bottom surface of the cylinder portion.

12. The supercharger of claim 1, further comprising:

a pressure adjustment mechanism portion (54), the pressure adjustment mechanism portion (54) being configured to adjust the pressure of the compressible fluid output from the output port to the secondary pressure,

wherein the pressure adjustment mechanism portion includes a pressure adjustment valve element (56), a relief valve element (58), and a regulator valve element (66).

13. The supercharger of claim 12, wherein:

the pressure regulating valve element being movable against a biasing force of a pressure regulating spring (64) in dependence on a pressure in a feedback chamber (76) communicating with the output port; and is

The supply port is connected to the pilot switching valve when the regulator valve element is pushed by the pressure regulating valve element via the release valve element.

14. The supercharger of claim 13, further comprising a pressure adjustment handle (60), the pressure adjustment handle (60) configured to adjust the biasing force of the pressure adjustment spring.

Technical Field

The present invention relates to a supercharger that increases the pressure of a compressible fluid (e.g., compressed air) prior to outputting the fluid.

Background

Superchargers are well known in the art, which include a pair of cylinder portions on both sides of a center housing and are configured to increase the pressure of supplied compressed air by reciprocating a pair of pistons coupled to each other to output the compressed air.

In a supercharger described in, for example, japanese laid-open patent publication No.02-212908, each of a pair of cylinder portions is partitioned into a pressurizing chamber and a driving chamber by a piston, and a switching valve switches a connection target of each of the pair of driving chambers between an output port and an exhaust port of a pressure control valve. In a supercharger, the position of the switching valve is switched when the piston pushes the push rod at the end of the stroke.

Disclosure of Invention

However, in the above-described supercharger, when the piston is driven at a low speed (e.g., at the end of the operation), the urging force of the piston may not act on the switching valve near the neutral position. This may cause the switching valve to stop in the neutral position.

The present invention has been made in view of the above problems, and an object thereof is to provide a supercharger capable of preventing a switching valve from stopping at a neutral position during use.

The supercharger according to the present invention comprises: a first cylinder portion provided at one side of the center housing; a second cylinder portion disposed at the other side of the center housing; a first piston in the first cylinder portion and a second piston in the second cylinder portion, the first piston and the second piston being interconnected and configured to increase a pressure of a compressible fluid supplied to the supply port from a primary pressure to a secondary pressure and output the compressible fluid from the output port by a reciprocating motion; and a pilot switching valve configured to alternately contact the first piston and the second piston. The pilot switching valve includes a movable valve element inserted inside a fixed valve element and a pilot valve element inserted inside the movable valve element, and is provided with a first pilot chamber disposed adjacent to one end of the movable valve element and a second pilot chamber disposed adjacent to the other end of the movable valve element.

According to the above-described pressure booster, the movable valve element is driven by the air pressure in the first pilot chamber and the second pilot chamber. Therefore, the pilot switching valve does not stop at the neutral position when the supercharger is used. Further, since the pilot valve element is provided inside the movable valve element, the supercharger can be made compact.

The pilot switching valve of the supercharger according to the present invention includes a movable valve element inserted inside a fixed valve element and a pilot valve element inserted inside the movable valve element, and is provided with a first pilot chamber disposed adjacent to one end of the movable valve element and a second pilot chamber disposed adjacent to the other end of the movable valve element. Therefore, the pilot switching valve does not stop at the neutral position when the supercharger is used, and the supercharger can be made compact.

The above and other objects, features and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings in which preferred embodiments of the present invention are shown by way of illustrative examples.

Drawings

FIG. 1 is a cross-sectional view of a supercharger according to an embodiment of the present invention;

FIG. 2 is a cross-sectional view of the supercharger of FIG. 1 taken at various points;

FIG. 3 is a cross-sectional view of the supercharger of FIG. 1 taken at a different point and viewed from a different direction;

fig. 4 is an enlarged view of a portion a in fig. 1;

fig. 5 is an enlarged view of a portion B in fig. 1;

FIG. 6 is a diagram corresponding to FIG. 1 when the supercharger of FIG. 1 is in a predetermined operating state;

fig. 7 is a diagram corresponding to fig. 5 and showing a first operating state of the pilot switching valve of the supercharger in fig. 1;

fig. 8 is a diagram corresponding to fig. 5 and showing a second operating state of the pilot switching valve of the supercharger in fig. 1;

fig. 9 is a diagram corresponding to fig. 5 and showing a third operating state of the pilot switching valve of the supercharger in fig. 1;

fig. 10 is a diagram corresponding to fig. 5 and showing a fourth operating state of the pilot switching valve of the supercharger in fig. 1;

fig. 11 is a diagram corresponding to fig. 5 and showing a fifth operating state of the pilot switching valve of the supercharger in fig. 1;

fig. 12 is a diagram corresponding to fig. 5 and showing a sixth operating state of the pilot switching valve of the supercharger in fig. 1;

fig. 13 is a diagram corresponding to fig. 5 and showing a seventh operating state of the pilot switching valve of the supercharger in fig. 1;

fig. 14 is a diagram corresponding to fig. 5 and showing an eighth operating state of the pilot switching valve of the supercharger in fig. 1;

fig. 15 is a diagram corresponding to fig. 5 and showing a ninth operating state of the pilot switching valve of the supercharger in fig. 1;

fig. 16 is a diagram corresponding to fig. 5 for illustrating how the movable valve element is disengaged from the intermediate position when the pilot switching valve of the supercharger of fig. 1 is in a predetermined state;

fig. 17 is a diagram corresponding to fig. 5 for illustrating how the movable valve element is disengaged from the intermediate position when the pilot switching valve of the supercharger of fig. 1 is in another state;

fig. 18 is a diagram corresponding to fig. 5 and showing a state before the movable valve element is disengaged from the intermediate position when the pilot switching valve of the supercharger of fig. 1 is in yet another state; and

FIG. 19 is a view related to FIG. 18 and showing the movable valve element after disengagement from the intermediate position.

Detailed Description

Preferred embodiments of a supercharger according to the present invention will be described in detail below with reference to the accompanying drawings. In the following description, terms regarding directions (such as up, down, left, and right) refer to directions on the drawings, and are not based on the actual arrangement of the supercharger.

As shown in fig. 1 to 3, the supercharger 10 according to this embodiment includes a center housing 12 that houses therein a drive mechanism unit, a first cylinder portion 18 provided on one side of the center housing 12, and a second cylinder portion 20 provided on the other side of the center housing 12. The center housing 12 includes a rectangular parallelepiped first body 14 and a cylindrical second body 16 disposed above the first body 14.

The first body 14 is provided with: a supply port 22 to which air (compressed air) as a compressible fluid at a primary pressure is supplied from an air supply source (not shown); an output port 24 from which air at an elevated pressure is output; and a discharge port 26 from which air is discharged from the discharge port 26. The supply port 22 and the output port 24 are opened in one side surface of the rectangular parallelepiped first body 14, and the discharge port 26 is opened in the opposite side surface.

The first body 14 is provided with a first supply path 34a and a first output path 36a that open in a side surface to which the first cylinder portion 18 is connected, and with a second supply path 34b and a second output path 36b that open in a side surface to which the second cylinder portion 20 is connected. The first and second supply paths 34a and 34b communicate with the supply port 22, and the first and second output paths 36a and 36b communicate with the output port 24.

The first supply path 34a is provided with a first supply check valve 34a 1. The first supply check valve 34a1 allows passage of air from the supply port 22 to the first plenum 48a (described below) and prevents air from flowing from the first plenum 48a to the supply port 22. The second supply path 34b is provided with a second supply check valve 34b 1. The second supply check valve 34b1 allows passage of air from the supply port 22 to the second plenum 48b (described below) and prevents air from flowing from the second plenum 48b to the supply port 22.

The first output path 36a is provided with a first output check valve 36a 1. The first output check valve 36a1 allows passage of air from the first plenum 48a to the output port 24 and prevents air from flowing from the output port 24 to the first plenum 48 a. The second output path 36b is provided with a second output check valve 36b 1. The second output check valve 36b1 allows passage of air from the second plenum 48b to the output port 24 and prevents air from flowing from the output port 24 to the second plenum 48 b.

The first cylinder portion 18 includes a first cylinder tube 40 and a first piston 42. The first piston 42 is movably disposed in a piston slide hole 40a formed inside the first cylinder pipe 40. The piston slide hole 40a is partitioned by the first piston 42 into a first pressurizing chamber 48a provided adjacent to the first body 14 and a first driving chamber 50a provided on the side opposite to the side where the first body 14 is located.

The second block section 20 includes a second cylinder tube 44 and a second piston 46. The second piston 46 has the same shape as the first piston 42, and is movably disposed in a piston slide hole 44a formed inside the second cylinder pipe 44. The piston slide hole 44a is partitioned by the second piston 46 into a second pressurizing chamber 48b provided adjacent to the first body 14 and a second driving chamber 50b provided on the side opposite to the side where the first body 14 is located.

The first and second pistons 42, 46 are joined together as one piece by a piston rod 52. The piston rod 52 is inserted into the first body 14 and supported by the first body 14. First cylinder pipe 40 is provided with a first air conduit 51a for connecting a pilot switching valve 78 (described below) to first drive chamber 50 a. Second cylinder pipe 44 is provided with a second air conduit 51b for connecting pilot switching valve 78 to second drive chamber 50 b.

The drive mechanism unit includes a pressure adjustment mechanism portion 54, and the pressure adjustment mechanism portion 54 is configured to increase the pressure of the air output from the output port 24 to a predetermined secondary pressure, and after the increase, maintain the secondary pressure while decelerating or stopping the first and second pistons 42 and 46. The drive mechanism unit further includes a pilot switching valve 78, and the pilot switching valve 78 is configured to switch a supply state of air to be supplied between the first drive chamber 50a and the second drive chamber 50b to switch the moving direction of the first piston 42 and the second piston 46.

First, the structure of the pressure adjustment mechanism portion 54 will be described mainly with reference to fig. 4. The first body 14 is provided with a vertical hole 28 transverse to the supply port 22 and opening in the upper surface of the first body 14. A valve block 74 supporting the pressure regulating valve element 56 and the regulator valve element 66 is fixed to the inner periphery of the vertical hole 28.

The pressure-adjusting valve element 56 includes a large-diameter cylindrical portion 56a inserted into a slide hole 74a formed in an upper portion of the valve block 74, a small-diameter cylindrical portion 56b formed above the large-diameter cylindrical portion 56a, and a flange portion 56c protruding outward from an upper end of the large-diameter cylindrical portion 56 a. The flange portion 56c contacts the upper surface of the valve block 74 to restrict downward movement of the pressure regulating valve member 56.

The pressure-adjusting valve element 56 includes a small-diameter hole portion 56d that opens in the upper surface of the small-diameter cylindrical portion 56b, and a large-diameter hole portion 56e that adjoins the small-diameter hole portion 56d and opens in the lower surface of the large-diameter cylindrical portion 56 a. A rod-shaped release (relief) valve element 58 is inserted into the small-diameter hole portion 56d and the large-diameter hole portion 56e of the pressure regulating valve element 56. A tapered surface 58a is formed in the middle of the relief valve element 58 in the axial direction, and cooperates with an angular portion 56f formed at the lower end of the small-diameter hole portion 56d of the pressure regulating valve element 56. The feedback chamber 76 is formed at an intermediate portion of the valve block 74 in the vertical direction, and communicates with the output port 24 via a path (not shown).

When the tapered surface 58a of the release valve member 58 contacts the corner portion 56f of the pressure regulating valve member 56, the feedback chamber 76 is insulated from the interior space 38 of the second body 16. On the other hand, when the tapered surface 58a of the relief valve element 58 is separated from the corner portion 56f of the pressure regulating valve element 56, the feedback chamber 76 communicates with the internal space 38 of the second body 16. The internal space 38 of the second body 16 is always exposed to the atmosphere via a release hole 39 formed in the second body 16. Therefore, when the tapered surface 58a of the relief valve member 58 is separated from the corner portion 56f of the pressure regulating valve member 56, the air in the feedback chamber 76 is opened to the atmosphere.

A rotatable pressure adjustment handle 60 is provided on the outer periphery of the second body 16. A shank portion 60a attached to the pressure adjustment handle 60 extends inside the second body 16 and engages a nut member 62 disposed inside the second body 16. The nut member 62 is supported by the second body 16 so as to be movable in the axial direction (vertical direction) and not rotatable about the axis.

A pressure-adjusting spring 64 formed of a coil spring is disposed between the nut member 62 and the pressure-adjusting valve element 56. The pressure adjustment valve element 56 is biased downward by a pressure adjustment spring 64. The biasing force of the pressure adjustment spring 64 can be adjusted by rotating the pressure adjustment handle 60 to change the position of the nut member 62. This allows the secondary pressure of the air output from the output port 24 to be set at a desired level. When the nut member 62 is located at the uppermost position, the biasing force of the pressure-adjusting spring 64 is approximately zero.

When the tapered surface 58a of the relief valve element 58 comes into contact with the corner portion 56f of the pressure regulating valve element 56, the pressure regulating valve element 56 is biased upward by the air pressure in the feedback chamber 76. When the biasing force of the air pressure in the feedback chamber 76 exceeds the biasing force of the pressure-adjusting spring 64, the flange portion 56c of the pressure-adjusting valve element 56 is separated from the upper surface of the valve block 74, and the pressure-adjusting valve element 56 moves upward.

The regulator valve element 66 includes: a cylindrical guide portion 66a inserted into a slide hole 74b formed in a lower portion of the valve block 74; and a valve portion 66b having a diameter larger than that of the guide portion 66a and disposed below the guide portion 66a in a coupled manner. An annular rubber member 66c is attached to the upper surface of the valve portion 66b adjacent the outer periphery to cooperate with an annular protrusion 74c protruding from the lower surface of the valve block 74. The valve portion 66b has a communication hole (not shown) that passes through the valve portion 66b in the vertical direction at a position closer to the inner periphery than the rubber member 66 c.

A space 72 adjacent to the outer periphery of the valve portion 66b is connected to the supply port 22, and a space 70 below the valve portion 66b is connected to a supply opening 80c of a pilot switching valve 78 (described below). When the rubber member 66c on the valve portion 66b is in contact with the annular projection 74c of the valve block 74, the space 70 below the valve portion 66b is insulated from the space 72 adjacent to the outer periphery of the valve portion 66 b. On the other hand, when the rubber member 66c on the valve portion 66b is separated from the annular protrusion 74c of the valve block 74, the space 70 below the valve portion 66b is connected to the space 72 adjacent to the outer periphery of the valve portion 66b via the communication hole of the valve portion 66 b.

The regulator valve element 66 is biased upward by a regulator spring 68 formed by a coil spring provided in the bottom of the vertical hole 28 in the first body 14, and the upper end of the guide portion 66a is in contact with the lower end of the release valve element 58. The spring constant of the regulating spring 68 is smaller than that of the pressure-adjusting spring 64.

When the flange portion 56c of the pressure regulating valve member 56 comes into contact with the upper surface of the valve block 74 as the pressure regulating valve member 56 is biased downward by the pressure regulating spring 64, the relief valve member 58 is pushed downward by the pressure regulating valve member 56, and the regulator valve member 66, which is in contact with the lower end of the relief valve member 58, is also pushed downward against the biasing force of the regulator spring 68. Therefore, the rubber member 66c on the valve portion 66b is separated from the annular protrusion 74c of the valve block 74, and the space 70 below the valve portion 66b communicates with the space 72 adjacent to the outer periphery of the valve portion 66 b. This allows air from supply port 22 to be supplied to supply opening 80c of pilot switching valve 78.

On the other hand, when the biasing force of the air pressure in the feedback chamber 76 exceeds the biasing force of the pressure-adjusting spring 64, the pressure-adjusting valve element 56 moves upward, and the regulator valve element 66 moves upward due to the biasing force of the regulator spring 68. Thus, the rubber member 66c on the valve portion 66b is in contact with the annular protrusion 74c of the valve block 74, and the space 70 below the valve portion 66b is insulated from the space 72 adjacent to the outer periphery of the valve portion 66 b. This prevents air from supply port 22 from being supplied to supply opening 80c of pilot switching valve 78.

The seal member 13a and the seal member 13b are provided on the outer periphery of the upper portion of the valve block 74 and the outer periphery of the large-diameter cylindrical portion 56a of the pressure adjusting valve element 56, respectively, so that the feedback chamber 76 and the internal space 38 of the second body 16 can be insulated from each other. In addition, the seal member 13c and the seal member 13d are provided on the outer periphery of the lower portion of the valve block 74 and the outer periphery of the guide portion 66a of the regulator valve element 66, respectively, so that the feedback chamber 76 and the space 72 adjacent to the outer periphery of the valve portion 66b can be insulated from each other.

Next, the structure of pilot switching valve 78 will be described mainly with reference to fig. 5. The first body 14 has a horizontal hole 30 passing through the first body 14 and accommodating a pilot switching valve 78. Further, the first body 14 has a first connection hole 32a connecting the pilot switching valve 78 and the first air duct 51a and a second connection hole 32b connecting the pilot switching valve 78 and the second air duct 51b below the horizontal hole 30.

Pilot switching valve 78 includes: a cylindrical main fixed valve element (fixed valve element) 80 fixed inside the horizontal hole 30; a movable valve element 88 inserted inside the main fixed valve element 80 to be movable in an axial direction with respect to the main fixed valve element 80; and a pilot valve element 100 inserted inside the movable valve element 88 to be movable in the axial direction relative to the movable valve element 88.

The main fixed valve element 80 has a first discharge opening 80a, a first drive chamber connection opening 80b, a supply opening 80c, a second drive chamber connection opening 80d, and a second discharge opening 80e arranged in the axial direction of the main fixed valve element 80. The first discharge opening 80a and the second discharge opening 80e communicate with the discharge port 26. The first drive chamber connection opening 80b communicates with the first drive chamber 50a via a first air duct 51a, and the second drive chamber connection opening 80d communicates with the second drive chamber 50b via a second air duct 51 b. The supply opening 80c communicates with the space 70 below the valve portion 66b of the regulator valve element 66.

The seal members 15a to 15d are attached to the outer periphery of the main fixed valve element 80 at positions between the first discharge opening 80a and the first drive chamber connection opening 80b, between the first drive chamber connection opening 80b and the supply opening 80c, between the supply opening 80c and the second drive chamber connection opening 80d, and between the second drive chamber connection opening 80d and the second discharge opening 80e, respectively, and are in contact with the wall surface of the horizontal hole 30.

A stack of a first insert plate 82a and a first side plate 84a is disposed between the first body 14 and the first cylinder tube 40. The first insert plate 82a is in contact with an end of the main fixed valve element 80 and includes a flange portion 82a1, the flange portion 82a1 having a hole portion 82a2 formed at a position corresponding to the horizontal hole 30 of the first body 14. The first side plate 84a includes a flange portion 84a1 having a hole portion 84a2, the hole portion 84a2 corresponding to the hole portion 82a2 of the first insertion plate 82 a. The first secondary fixed valve element 86a is disposed between the flange portion 82a1 of the first insertion plate 82a and the flange portion 84a1 of the first side plate 84 a.

A sealing member 15e is provided between the first body 14, the first insert plate 82a and the main fixed valve element 80. A sealing member 15f is provided between the first insertion plate 82a, the first side plate 84a and the first secondary fixed valve element 86 a. Further, a seal member 15g is provided between the first side plate 84a and the first sub-fixed valve element 86a to be in sliding contact with the movable valve element 88.

A stack of a second insert plate 82b and a second side plate 84b is disposed between the first body 14 and the second cylinder tube 44. The second insert plate 82b is in contact with an end of the main fixed valve element 80 and includes a flange portion 82b1 having a bore portion 82b2, the bore portion 82b2 being formed at a location corresponding to the horizontal bore 30 of the first body 14. The second side plate 84b includes a flange portion 84b1 having a hole portion 84b2, the hole portion 84b2 corresponding to the hole portion 82b2 of the second insert plate 82 b. The second secondary fixed valve element 86b is disposed between the flange portion 82b1 of the second insert plate 82b and the flange portion 84b1 of the second side plate 84 b.

The sealing member 15h is provided between the first body 14, the second insertion plate 82b, and the main fixed valve element 80. A seal member 15i is disposed between the second insert plate 82b, the second side plate 84b and the second secondary fixed valve element 86 b. Further, a seal member 15j is provided for sliding contact of the second sub-fixed valve element 86b with the movable valve element 88.

The movable valve element 88 includes a first valve portion 90 and a second valve portion 92. The first valve portion 90 includes: a thick-walled large-diameter body portion 90a that is in sliding contact with two seal members 15k and 15m attached to the inner periphery of the main fixed valve element 80; a thin-walled small-diameter cylindrical end portion 90b joined to one end of the body portion 90 a; and a connection end portion 90c coupled to the other end of the large diameter portion. The cylindrical end portion 90b of the first valve portion 90 has a first radial hole 90d passing through the cylindrical end portion 90b in the radial direction. The body portion 90a of the first valve portion 90 has: a second radial hole 90e passing through the body portion 90a in the radial direction at a position adjacent to the cylindrical end portion 90 b; and a third radial hole 90f that passes through the body portion 90a in the radial direction at a position adjacent to the connection end portion 90 c. A cylindrical end portion 90b of the first valve portion 90 protrudes inside the first pressurizing chamber 48a and is able to come into contact with the first piston 42.

The second valve portion 92 includes: a thick-walled large-diameter body portion 92a that is in sliding contact with two seal members 15n and 15p attached to the inner periphery of the main fixed valve element 80; a thin-walled cylindrical connecting end portion 92c joined to one end of the body portion 92 a; and a thin-walled small-diameter cylindrical end portion 92b joined to the other end of the body portion 92 a. The body portion 92a of the second valve portion 92 has: a fourth radial hole 92d passing through the body portion 92a in the radial direction at a position adjacent to the connection end portion 92 c; a fifth radial hole 92e passing through the body portion 92a in the radial direction at the middle in the axial direction; and a sixth radial hole 92f that passes through the body portion 92a in the radial direction at a position adjacent to the cylindrical end portion 92 b. The body portion 92a is provided with a flange portion 92h projecting outward from the outer periphery at a position between the fourth radial hole 92d and the fifth radial hole 92 e. The cylindrical end portion 92b of the second valve portion 92 protrudes inside the second pressurizing chamber 48b and can be in contact with the second piston 46.

The connection end portion 90c of the first valve portion 90 is inserted into a predetermined position in the connection end portion 92c of the second valve portion 92, and is connected to the connection end portion 92c by a screw connection. The connection portion is provided with a sealing member 15 q. The sleeve 94 is disposed adjacent to the outer peripheries of the connecting end portion 90c of the first valve portion 90 and the connecting end portion 92c of the second valve portion 92 so as to be held between the end surface of the body portion 90a of the first valve portion 90 and the flange portion 92h of the second valve portion 92. The sleeve 94 includes: a first land portion 94a that protrudes toward the inside of the main fixed valve element 80 at a position adjacent to the body portion 90a of the first valve portion 90; and a second land portion 94b that protrudes toward the inside of the main fixed valve element 80 at a position adjacent to the flange portion 92h of the second valve portion 92.

A left annular chamber 94c located on the left side of the first land portion 94a, an intermediate annular chamber 94d located between the first land portion 94a and the second land portion 94b, and a right annular chamber 94e located on the right side of the second land portion 94b are formed between the inner periphery of the main fixed valve element 80 and the outer periphery of the movable valve element 88. The left annular chamber 94c is connected to the first discharge opening 80a, and the right annular chamber 94e is connected to the second discharge opening 80 e.

The movable valve element 88 is movable between a position where the end surface of the body portion 90a of the first valve portion 90 contacts the first insertion plate 82a and a position where the end surface of the body portion 92a of the second valve portion 92 contacts the second insertion plate 82 b. When the end surface of the body portion 90a of the first valve portion 90 comes into contact with or approaches the first insertion plate 82a, the supply opening 80c is connected to the first drive chamber connection opening 80b via the intermediate annular chamber 94d, and the communication between the supply opening 80c and the second drive chamber connection opening 80d is cut off by the second land portion 94 b. When the end surface of the body portion 92a of the second valve portion 92 comes into contact with or approaches the second insertion plate 82b, the communication between the supply opening 80c and the first drive chamber connection opening 80b is cut off by the first land portion 94a, and the supply opening 80c is connected to the second drive chamber connection opening 80d via the intermediate annular chamber 94 d.

A first pilot chamber 96 surrounded by the first valve portion 90, the main fixed valve element 80, the first sub fixed valve element 86a, and the first insert plate 82a is formed on the left side of the body portion 90a of the first valve portion 90. A second pilot chamber 98 surrounded by the second valve portion 92, the main fixed valve element 80, the second sub fixed valve element 86b, and the second insert plate 82b is formed on the right side of the body portion 92a of the second valve portion 92. An area of the left end surface of main body portion 90a of first valve portion 90 (i.e., an area through which the air pressure in first pilot chamber 96 acts on main body portion 90a of first valve portion 90) is larger than an area of the right end surface of main body portion 92a of second valve portion 92 (i.e., an area through which the air pressure in second pilot chamber 98 acts on main body portion 92a of second valve portion 92).

The pilot valve element 100 comprises a first shaft portion 102a and a second shaft portion 102b connected in series. The piston portion 104 is attached to the middle of the pilot valve element 100 in the axial direction via a sealing member 15 r. The end of the first shaft portion 102a facing the first plenum chamber 48a may protrude from the first valve portion 90 of the movable valve element 88 and contact the first piston 42. The end of the second shaft portion 102b facing the second plenum chamber 48b may protrude from the second valve portion 92 of the movable valve element 88 and contact the second piston 46.

The piston portion 104 is provided in a cylinder portion 92g formed inside the connecting end portion 92c of the second valve portion 92 of the movable valve element 88, and is in sliding contact with a wall surface of the cylinder portion 92g via a seal member 15 s. The cylinder portion 92g is partitioned by the piston portion 104 into a piston left chamber 108 on the left side of the piston portion 104 and a piston right chamber 110 on the right side of the piston portion 104. The pilot valve element 100 is movable relative to the movable valve element 88 between a position where the piston portion 104 contacts the connecting end portion 90c of the first valve portion 90 of the movable valve element 88 and a position where the piston portion 104 contacts the bottom surface of the cylinder portion 92 g.

When the piston portion 104 of the pilot valve member 100 is in contact with the end of the connecting end portion 90c of the first valve portion 90 of the movable valve member 88, the length by which the second shaft portion 102b of the pilot valve member 100 protrudes from the second valve portion 92 of the movable valve member 88 is zero. Further, when the piston portion 104 of the pilot valve member 100 is in contact with the bottom surface of the cylinder portion 92g of the movable valve member 88, the length by which the first shaft portion 102a of the pilot valve member 100 protrudes from the first valve portion 90 of the movable valve member 88 is zero.

The pilot valve element 100 has a shaft hole 106 extending in the axial direction inside each of the first shaft portion 102a and the second shaft portion 102 b. The first shaft portion 102a has: a first radial hole 112a that branches from the left end of the shaft hole 106 and opens in the outer peripheral surface of the first shaft portion 102 a; and a second radial hole 112b that branches from the middle of the shaft hole 106 and opens in the outer peripheral surface of the first shaft portion 102 a. The second shaft portion 102b has a third radial hole 112c that branches from the right end of the shaft hole 106 and opens in the outer peripheral surface of the second shaft portion 102 b.

Three seal members (a first seal member 15t, a second seal member 15u, and a third seal member 15v) arranged in the axial direction are attached to the outer periphery of the first shaft portion 102a of the pilot valve element 100, and are in contact with the inner periphery of the first valve portion 90 of the movable valve element 88. Between the outer periphery of the first shaft portion 102a and the inner periphery of the first valve portion 90, a first annular gap 114a, a second annular gap 114b, and a third annular gap 114c are formed in the region between the first seal member 15t and the second seal member 15u, the region between the second seal member 15u and the third seal member 15v, and the region on the right side of the third seal member 15v, respectively.

The first radial hole 112a of the pilot valve element 100 faces the first annular clearance gap 114a, and the first pilot chamber 96 communicates with the shaft hole 106 of the pilot valve element 100 via the first radial hole 90d of the movable valve element 88, the first annular clearance gap 114a, and the first radial hole 112a of the pilot valve element 100. The second radial hole 112b of the pilot valve element 100 faces the third annular clearance gap 114c, and the piston left chamber 108 communicates with the shaft bore 106 of the pilot valve element 100 via the third annular clearance gap 114c and the second radial hole 112b of the pilot valve element 100.

Three seal members (a fourth seal member 15w, a fifth seal member 15x, and a sixth seal member 15y) arranged in the axial direction are attached to the outer periphery of the second shaft portion 102b of the pilot valve element 100, and are in contact with the inner periphery of the second valve portion 92 of the movable valve element 88. Between the outer periphery of the second shaft portion 102b and the inner periphery of the second valve portion 92, a fourth annular gap 114d, a fifth annular gap 114e, and a sixth annular gap 114f are formed in the region on the left side of the fourth seal member 15w, in the region between the fourth seal member 15w and the fifth seal member 15x, and in the region between the fifth seal member 15x and the sixth seal member 15y, respectively.

The fourth radial hole 92d of the movable valve element 88 opens in the fourth annular gap 114d, and the piston right chamber 110 communicates with the right annular chamber 94e and the left annular chamber 94c via the fourth annular gap 114d, the fourth radial hole 92d of the movable valve element 88, a gap between the sleeve 94 and the second valve portion 92 of the movable valve element 88, and the like. Therefore, the piston right chamber 110 is always connected to the discharge port 26.

The first body 14 is provided with a pilot path 116 that connects the second pilot chamber 98 to the space 72 adjacent to the outer periphery of the valve portion 66b of the regulator valve element 66, and the second pilot chamber 98 is connected to the supply port 22 via the pilot path 116 and the space 72 adjacent to the outer periphery of the valve portion 66 b.

The supercharger 10 according to the embodiment of the present invention is basically configured as above. Next, the effect and operation thereof will be described.

First, it is assumed that when the nut member 62 is located at the uppermost position as shown in fig. 1, air at a primary pressure is supplied from an air supply source (not shown) to the supply port 22, and therefore the biasing force of the pressure adjusting spring 64 on the pressure adjusting valve element 56 is approximately zero.

The air supplied to the supply port 22 enters the first plenum chamber 48a through the first supply path 34a provided with the first supply check valve 34a1, and also enters the second plenum chamber 48b through the second supply path 34b provided with the second supply check valve 34b 1. The air having entered the first plenum chamber 48a is output from the output port 24 to the outside through the first output path 36a provided with the first output check valve 36a1, and the air having entered the second plenum chamber 48b is output from the output port 24 to the outside through the second output path 36b provided with the second output check valve 36b 1.

At this time, since the thrust force acting on the first piston 42 and the thrust force acting on the second piston 46 are balanced with each other, the first piston 42 and the second piston 46 coupled to each other by the piston rod 52 are not driven. Air from the supply port 22 is output (discharged) from the output port 24, but its pressure does not increase as described above.

On the other hand, the regulator valve element 66 is located at the uppermost position due to the biasing force of the regulator spring 68, and a space 70 below the valve portion 66b is insulated from a space 72 adjacent to the outer periphery of the valve portion 66 b. Therefore, air from supply port 22 is not supplied to supply opening 80c of pilot switching valve 78. Air from the supply port 22 enters the pilot path 116 through the space 72 adjacent to the outer periphery of the valve portion 66b, and is supplied to the second pilot chamber 98. As a result, the movable valve element 88 moves leftward with respect to the main fixed valve element 80, and therefore, the pilot valve element 100 also moves leftward when pushed by the movable valve element 88.

Next, in order to adjust the pressure of the air output to the outside from the output port 24 to a desired secondary pressure, the pressure adjustment handle 60 is manually rotated to move the nut member 62 downward to apply the biasing force of the pressure adjustment spring 64 to the pressure adjustment valve element 56 (see fig. 6). Thus, the pressure regulating valve member 56 and the relief valve member 58 are pushed downward, and therefore, the regulator valve member 66 is also pushed downward by the relief valve member 58. As a result, the rubber member 66c on the valve portion 66b is separated from the annular protrusion 74c of the valve block 74, and the space 70 below the valve portion 66b communicates with the space 72 adjacent to the outer periphery of the valve portion 66 b. The air supplied to supply port 22 in this state is supplied to supply opening 80c of pilot switching valve 78.

At this time, it is assumed that the movable valve element 88 is located at the leftmost position with respect to the main fixed valve element 80, the pilot valve element 100 is located at the leftmost position with respect to the movable valve element 88, and the movable valve element 88 and the pilot valve element 100 protrude to their maximum values inside the first pressurizing chamber 48 a. The first drive chamber connection opening 80b is connected to the supply opening 80c via an intermediate annular chamber 94d, and the second drive chamber connection opening 80d is connected to the second discharge opening 80e via a right annular chamber 94 e. Thus, air from the supply port 22 is supplied to the first drive chamber 50a, while air inside the second drive chamber 50b is discharged from the discharge port 26.

Air from the supply port 22 is also supplied to the second supply path 34 b. The air supplied to the second supply path 34b is supplied to the second plenum chamber 48b through the second supply check valve 34b 1. Accordingly, thrust from the air supplied to the first drive chamber 50a acts on the first piston 42, and thrust from the air supplied to the second pressurizing chamber 48b acts on the second piston 46. The combined thrust forces drive the first and second pistons 42, 46, which are joined together in one piece by the piston rod 52, to the right. This causes the volume of the first plenum chamber 48a to decrease and the air pressure in the first plenum chamber 48a to increase accordingly. Although air from the supply port 22 is also supplied to the first supply path 34a, the first supply check valve 34a1 provided for the first supply path 34a closes the first supply path 34a due to the increase in air pressure in the first plenum chamber 48 a.

The air in the first pressurizing chamber 48a at the increased pressure flows through the first output path 36a provided with the first output check valve 36a1, and is output from the output port 24 to the outside. The second output check valve 36b1 provided for the second output path 36b closes the second output path 36b because the air pressure at the output port 24 (the air pressure in the first plenum 48 a) is higher than the air pressure in the second plenum 48 b.

When the air pressure at the output port 24 reaches the predetermined secondary pressure, the biasing force of the air pressure in the feedback chamber 76 communicating with the output port 24 exceeds the biasing force of the pressure-adjusting spring 64, and the pressure-adjusting valve element 56 moves upward. Thereby, the regulator valve element 66 also moves upward, and the rubber member 66c on the valve portion 66b comes into contact with the annular protrusion 74c of the valve block 74. As a result, the space 70 below the valve portion 66b is insulated from the space 72 adjacent to the outer periphery of the valve portion 66 b.

Accordingly, the supply of air from the supply port 22 to the supply opening 80c of the pilot switching valve 78 is stopped, and thus the supply of air to the first drive chamber 50a is stopped. Although the supply of air from the supply port 22 to the second plenum chamber 48b via the second supply path 34b continues, the first and second pistons 42, 46 slow down or stop as the supply of air to the first drive chamber 50a stops.

As the air in the first plenum chamber 48a continues to be output to the exterior from the output port 24 through the first output path 36a, the air pressure in the first plenum chamber 48a decreases as the first piston 42 decelerates or stops, and the air pressure at the output port 24 decreases to less than the predetermined secondary pressure. As a result, the biasing force of the air pressure in the feedback chamber 76 becomes smaller than the biasing force of the pressure-adjusting spring 64, and the pressure-adjusting valve element 56 moves downward. Therefore, the space 70 below the valve portion 66b communicates with the space 72 adjacent to the outer periphery of the valve portion 66 b. That is, the air pressure at the output port 24 returns to the state before reaching the secondary pressure.

First and second pistons 42 and 46 are driven to the right while the air pressure at output port 24 repeatedly reaches and becomes less than the secondary pressure as described above. Then, the first piston 42 is in contact with the first shaft portion 102a of the pilot valve element 100 to push the pilot valve element 100 to the right.

As shown in fig. 7, the first pilot chamber 96 and the piston left chamber 108 are connected to the exhaust port 26 during a period before and after the first piston 42 is in contact with the first shaft portion 102a of the pilot valve element 100. Details of the communication path between the piston left chamber 108 and the exhaust port 26 are as follows. As described above, the second pilot chamber 98 is always connected to the supply port 22, and the piston right chamber 110 is always connected to the discharge port 26.

The piston left chamber 108 is connected to the exhaust port 26 via a third annular clearance gap 114c, a second radial hole 112b of the pilot valve element 100, the shaft hole 106, a third radial hole 112c of the pilot valve element 100, a fifth annular clearance gap 114e, a fifth radial hole 92e of the movable valve element 88, a right annular chamber 94e, and a second exhaust opening 80 e. Further, the piston left chamber 108 is connected to the discharge port 26 via a third annular clearance 114c, a second radial hole 112b of the pilot valve element 100, the shaft hole 106, a first radial hole 112a of the pilot valve element 100, a first annular clearance 114a, a first radial hole 90d of the movable valve element 88, the first pilot chamber 96, a second radial hole 90e of the movable valve element 88, a second annular clearance 114b, a third radial hole 90f of the movable valve element 88, the left annular chamber 94c, and the first discharge opening 80 a.

When the pilot valve element 100 is pushed by the first piston 42 and moves rightward by a predetermined distance, the length by which the first shaft portion 102a of the pilot valve element 100 protrudes from the first valve portion 90 of the movable valve element 88 becomes zero, and the first piston 42 comes into contact with both the first shaft portion 102a of the pilot valve element 100 and the first valve portion 90 of the movable valve element 88. At this time, the piston portion 104 of the pilot valve element 100 is in contact with the bottom surface of the cylinder portion 92g of the movable valve element 88. Therefore, the pilot valve element 100 and the movable valve element 88 are pushed by the first piston 42 and moved rightward in an integrated manner.

As shown in fig. 8, communication between the piston left chamber 108 and the exhaust port 26 is cut off during a period of time before and after the first piston 42 starts to push both the pilot valve element 100 and the movable valve element 88. Communication between the piston left chamber 108 and the discharge port 26 is shut off because, in the above-described path from the piston left chamber 108 to the discharge port 26, communication between the second radial hole 90e of the movable valve element 88 and the second annular clearance 114b and between the fifth annular clearance 114e and the fifth radial hole 92e of the movable valve element 88 is shut off.

When the pilot valve element 100 and the movable valve element 88 are pushed by the first piston 42 and move rightward by a predetermined distance or more, the first pilot chamber 96 and the piston left chamber 108 communicate with the second pilot chamber 98 connected to the supply port 22, as shown in fig. 9. The air path from second pilot chamber 98 to first pilot chamber 96 and from second pilot chamber 98 to piston left chamber 108 is detailed as follows.

The second pilot chamber 98 is connected to the first pilot chamber 96 via the sixth radial hole 92f of the movable valve element 88, the fifth annular clearance 114e, the third radial hole 112c of the pilot valve element 100, the shaft hole 106, the first radial hole 112a of the pilot valve element 100, the first annular clearance 114a, and then either the first radial hole 90d of the movable valve element 88 or the second radial hole 90e of the movable valve element 88. Further, the second pilot chamber 98 is connected to the piston left chamber 108 via the sixth radial hole 92f of the movable valve element 88, the fifth annular clearance 114e, the third radial hole 112c of the pilot valve element 100, the shaft hole 106, the second radial hole 112b of the pilot valve element 100, and the third annular clearance 114 c.

When the first pilot chamber 96 communicates with the second pilot chamber 98, the primary pressure from the supply port 22 acts on the end surface of the body portion 90a of the first valve portion 90 that faces the first pilot chamber 96 to bias the movable valve element 88 rightward. Although the primary pressure from the supply port 22 acts on the end surface of the body portion 92a of the second valve portion 92 facing the second pilot chamber 98 to bias the movable valve element 88 leftward, since the area of the end surface of the body portion 90a of the first valve portion 90 is larger than the area of the end surface of the body portion 92a of the second valve portion 92, the rightward biasing force exceeds the leftward biasing force. Therefore, the movable valve element 88 is driven rightward by the primary pressure from the supply port 22 while being pushed and driven rightward by the first piston 42.

When the piston left chamber 108 is in communication with the second pilot chamber 98, the primary pressure from the supply port 22 acts on the piston portion 104 of the pilot valve member 100 to bias the pilot valve member 100 to the right. Therefore, when the pilot valve member 100 is pushed rightward by the first piston 42, the piston portion 104 of the pilot valve member 100 is pressed against the bottom surface of the cylinder portion 92g of the movable valve member 88. In addition, the piston portion 104 is pressed against the bottom surface of the cylinder portion 92g of the movable valve element 88 by the primary pressure from the supply port 22.

When the pilot valve element 100 and the movable valve element 88 move further rightward after the first pilot chamber 96 and the piston left chamber 108 communicate with the second pilot chamber 98, the first drive chamber connection opening 80b is connected to the first discharge opening 80a via the left annular chamber 94c, and the second drive chamber connection opening 80d is connected to the supply opening 80c via the intermediate annular chamber 94d, as shown in fig. 10. Thus, air from the supply port 22 is supplied to the second drive chamber 50b, and air inside the first drive chamber 50a is discharged from the discharge port 26.

Air from the supply port 22 is also supplied to the first supply path 34 a. The air supplied to the first supply path 34a is supplied to the first plenum chamber 48a through the first supply check valve 34a 1. The thrust of the air from the second drive chamber 50b acts on the second piston 46, and the thrust of the air from the first pressurizing chamber 48a acts on the first piston 42. The combined thrust forces begin to drive the first and second pistons 42, 46, which are joined together in one piece by the piston rod 52, to the left. This results in a decrease in the volume of the second plenum chamber 48b and a corresponding increase in the air pressure in the second plenum chamber 48 b. Although air from the supply port 22 is also supplied to the second supply path 34b, the second supply check valve 34b1 provided for the second supply path 34b closes the second supply path 34b due to the increase in air pressure in the second plenum chamber 48 b.

The air in the second pressurizing chamber 48b at the increased pressure flows through the second output path 36b provided with the second output check valve 36b1, and is output from the output port 24 to the outside. The first output check valve 36a1 provided for the first output path 36a closes the first output path 36a because the air pressure at the output port 24 (the air pressure in the second plenum 48 b) is higher than the air pressure in the first plenum 48 a.

When first and second pistons 42, 46 begin to move to the left, first piston 42 is separated from movable valve element 88 and pilot valve element 100. On the other hand, the piston portion 104 of the pilot valve element 100 is pressed against the bottom surface of the cylinder portion 92g of the movable valve element 88 by the primary pressure from the supply port 22, and the movable valve element 88 is driven rightward by the primary pressure from the supply port 22. Therefore, as shown in fig. 11, the movable valve element 88 is moved rightward until the end surface of the body portion 92a of the second valve portion 92 comes into contact with the second insertion plate 82b, and the movable valve element 88 and the pilot valve element 100 protrude to their maximum values inside the second pressurizing chamber 48 b.

With the first and second pistons 42, 46 driven to the right, the first and second pistons 42, 46 are driven to the left while the air pressure at the output port 24 repeatedly reaches and becomes less than the secondary pressure.

Then, as shown in fig. 12, the second piston 46 contacts the second shaft portion 102b of the pilot valve element 100 to push the pilot valve element 100 leftward. As shown in fig. 14, when the pilot valve member 100 is pushed by the second piston 46 and moved leftward by a predetermined distance, the length by which the second shaft portion 102b of the pilot valve member 100 protrudes from the second valve portion 92 of the movable valve member 88 becomes zero, and the second piston 46 is in contact with both the second shaft portion 102b of the pilot valve member 100 and the second valve portion 92 of the movable valve member 88. At this time, the piston portion 104 of the pilot valve element 100 is in contact with the connection end portion 90c of the first valve portion 90 of the movable valve element 88. Therefore, the pilot valve element 100 and the movable valve element 88 are pushed by the second piston 46 and move leftward in an integrated manner.

During the period of time from the second piston 46 contacting the second shaft portion 102b of the pilot valve element 100 to the second piston 46 contacting both the second shaft portion 102b of the pilot valve element 100 and the second valve portion 92 of the movable valve element 88, communication between the first pilot chamber 96 and the second pilot chamber 98 and between the piston left chamber 108 and the second pilot chamber 98 is cut off (see fig. 13). This is because the communication between the sixth radial hole 92f of the movable valve element 88 and the fifth annular clearance 114e is shut off.

When pilot valve element 100 and movable valve element 88 are pushed a predetermined distance to the left by second piston 46 after communication between first pilot chamber 96 and second pilot chamber 98 and between piston left chamber 108 and second pilot chamber 98 is cut off, the gas pressure in first pilot chamber 96 and piston left chamber 108 increases. This is because the volume of the piston left chamber 108 communicating with the first pilot chamber 96 decreases, and the volume of the first pilot chamber 96 also starts to decrease at some point.

As shown in fig. 15, when the pilot valve member 100 and the movable valve member 88 move leftward by the above-mentioned predetermined distance, the first pilot chamber 96 and the piston left chamber 108 are connected to the exhaust port 26. This places the air in the first pilot chamber 96 under increased pressure and the air in the piston left chamber 108 under increased pressure to exhaust from the exhaust port 26. The details of the air path from the first pilot chamber 96 to the exhaust port 26 and from the piston left chamber 108 to the exhaust port 26 are as follows.

The first pilot chamber 96 is connected to the drain port 26 via the second radial hole 90e of the movable valve element 88, the second annular gap 114b, the third radial hole 90f of the movable valve element 88, the left annular chamber 94c, and the first drain opening 80 a. Further, the first pilot chamber 96 is connected to the discharge port 26 via the first radial hole 90d of the movable valve element 88, the first annular clearance 114a, the first radial hole 112a of the pilot valve element 100, the shaft hole 106, the third radial hole 112c of the pilot valve element 100, the fifth annular clearance 114e, the fifth radial hole 92e of the movable valve element 88, the right annular chamber 94e, and the second discharge opening 80 e.

The piston left chamber 108 is connected to the exhaust port 26 via a third annular clearance gap 114c, a second radial hole 112b of the pilot valve element 100, the shaft hole 106, a first radial hole 112a of the pilot valve element 100, a first annular clearance gap 114a, a first radial hole 90d of the movable valve element 88, the first pilot chamber 96, a second radial hole 90e of the movable valve element 88, a second annular clearance gap 114b, a third radial hole 90f of the movable valve element 88, the left annular chamber 94c, and the first exhaust opening 80 a. Further, the piston left chamber 108 is connected to the discharge port 26 via a third annular clearance 114c, a second radial hole 112b of the pilot valve element 100, the shaft hole 106, a third radial hole 112c of the pilot valve element 100, a fifth annular clearance 114e, a fifth radial hole 92e of the movable valve element 88, the right annular chamber 94e, and the second discharge opening 80 e.

When the first pilot chamber 96 is connected to the drain port 26, the movable valve element 88 is driven leftward by the primary pressure from the supply port 22 in the second pilot chamber 98, while being pushed and driven leftward by the second piston 46. When the movable valve element 88 is moved further leftward, the first drive chamber connection opening 80b is connected to the supply opening 80c via the intermediate annular chamber 94d, and the second drive chamber connection opening 80d is connected to the second discharge port 80e via the right annular chamber 94 e. Thus, air from the supply port 22 is supplied to the first drive chamber 50a, and air within the second drive chamber 50b is discharged from the discharge port 26. The moving directions of the first piston 42 and the second piston 46 vary from left to right.

When the moving directions of the first piston 42 and the second piston 46 are shifted to the right, the second piston 46 is separated from the movable valve element 88 and the pilot valve element 100. On the other hand, since the movable valve element 88 is driven leftward by the primary pressure from the supply port 22 in the second pilot chamber 98, the movable valve element 88 is moved leftward until the end surface of the body portion 90a of the first valve portion 90 comes into contact with the first insertion plate 82 a. Therefore, the supercharger 10 returns to the initial state (the state before air is supplied to the supply port 22) and repeats the same movement thereafter.

Next, the operation of the components when the movable valve element 88 is stopped at the intermediate position (i.e., the position where the supply opening 80c is not connected to the first drive chamber connection opening 80b or the second drive chamber connection opening 80 d) while air at the primary pressure is not supplied to the supply port 22 will be described. Depending on the position of pilot valve element 100 relative to movable valve element 88, operation will be described in different circumstances below.

(when the pilot valve member 100 projects to its maximum extent to the right)

As shown in fig. 16, the movable valve element 88 is stopped at the neutral position while the pilot valve element 100 protrudes rightward to its maximum amount with respect to the movable valve element 88. In this case, when air at the primary pressure is supplied to the supply port 22, the air at the primary pressure is supplied to the second pilot chamber 98 through the space 72 adjacent to the outer periphery of the valve portion 66b and the pilot path 116.

The air at the primary pressure supplied to the second pilot chamber 98 is supplied to the first pilot chamber 96 via the sixth radial hole 92f of the movable valve element 88, the fifth annular gap 114e, the third radial hole 112c of the pilot valve element 100, the shaft hole 106, the first radial hole 112a of the pilot valve element 100, the first annular gap 114a, and the first radial hole 90d of the movable valve element 88. Therefore, the force of the air at the primary pressure acts on the end surface of the body portion 90a of the first valve portion 90 of the movable valve element 88 facing the first pilot chamber 96 to bias the movable valve element 88 rightward, and the force of the air at the same primary pressure acts on the end surface of the body portion 92a of the second valve portion 92 of the movable valve element 88 facing the second pilot chamber 98 to bias the movable valve element 88 leftward.

Since the area of the end surface of the body portion 90a of the first valve portion 90 is larger than the area of the end surface of the body portion 92a of the second valve portion 92, the biasing force to the right exceeds the biasing force to the left. Therefore, the movable valve element 88 is moved rightward until the end surface of the body portion 92a of the second valve portion 92 comes into contact with the second insertion plate 82b, and is disengaged from the stationary state at the intermediate position. Thereby, the second drive chamber connection opening 80d is connected to the supply opening 80c, and the first drive chamber connection opening 80b is connected to the first discharge opening 80 a. As a result, air from the supply port 22 is supplied to the second drive chamber 50b, and air in the first drive chamber 50a is discharged from the discharge port 26. The first and second pistons 42, 46 are driven to the left.

(when pilot valve element 100 projects to its maximum extent to the left)

As shown in fig. 17, the movable valve element 88 is stopped at the neutral position while the pilot valve element 100 protrudes leftward relative to the movable valve element 88 to its maximum amount. In this case, when air at the primary pressure is supplied to the supply port 22, the air at the primary pressure is supplied to the second pilot chamber 98 through the space 72 adjacent to the outer periphery of the valve portion 66b and the pilot path 116.

On the other hand, air in the first pilot chamber 96 is discharged from the discharge port 26 via the second radial hole 90e of the movable valve element 88, the second annular gap 114b, the third radial hole 90f of the movable valve element 88, the left annular chamber 94c, and the first discharge opening 80 a. Further, the air in the first pilot chamber 96 is discharged from the discharge port 26 via the first radial hole 90d of the movable valve element 88, the first annular clearance 114a, the first radial hole 112a of the pilot valve element 100, the shaft hole 106, the third radial hole 112c of the pilot valve element 100, the fifth annular clearance 114e, the fifth radial hole 92e of the movable valve element 88, the right annular chamber 94e, and the second discharge opening 80 e.

Therefore, the movable valve element 88 is moved leftward by the air at the primary pressure supplied to the second pilot chamber 98 until the end surface of the body portion 90a of the first valve portion 90 comes into contact with the first insertion plate 82a and is disengaged from the stationary state at the intermediate position. Thereby, the first drive chamber connection opening 80b is connected to the supply opening 80c, and the second drive chamber connection opening 80d is connected to the second discharge opening 80 e. As a result, air from the supply port 22 is supplied to the first drive chamber 50a, while air in the second drive chamber 50b is discharged from the discharge port 26. The first and second pistons 42, 46 are driven to the right.

(when the pilot valve member 100 is in the neutral position)

As shown in fig. 18, the movable valve member 88 stops at the intermediate position where the first shaft portion 102a of the pilot valve member 100 projects leftward from the movable valve member 88, and the second shaft portion 102b of the pilot valve member 100 projects rightward from the movable valve member 88. At this time, the piston portion 104 is not in contact with the connecting end portion 90c of the first valve portion 90 of the movable valve element 88 nor with the bottom surface of the cylinder portion 92 g.

In this case, the first pilot chamber 96 and the piston left chamber 108 are connected to each other via the first radial hole 90d of the movable valve element 88, the first annular clearance 114a, the first radial hole 112a of the pilot valve element 100, the shaft hole 106, the second radial hole 112b of the pilot valve element 100, and the third annular clearance 114 c. Further, the first pilot chamber 96 and the piston left chamber 108 are not connected to any one of the first discharge opening 80a, the second discharge opening 80e, and the second pilot chamber 98. That is, the first pilot chamber 96 and the piston left chamber 108 are closed spaces.

Since the communication between the second radial hole 90e of the movable valve element 88 and the second annular clearance 114b is cut off, the first pilot chamber 96 and the piston left chamber 108 are not connected to the first discharge opening 80 a. Since the communication between the fifth annular clearance 114e and the fifth radial hole 92e of the movable valve element 88 is cut off, the first pilot chamber 96 and the piston left chamber 108 are not connected to the second discharge opening 80 e. Since the communication between the fifth annular clearance 114e and the sixth radial hole 92f of the movable valve element 88 is cut off, the first pilot chamber 96 and the piston left chamber 108 are not connected to the second pilot chamber 98.

In this case, when air at the primary pressure is supplied to the supply port 22, the air at the primary pressure is supplied to the second pilot chamber 98 through the space 72 adjacent to the outer periphery of the valve portion 66b and the pilot path 116. Movable valve element 88 is moved leftward by air at the primary pressure supplied to second pilot chamber 98, and the volume of first pilot chamber 96 is decreased. As a result, the air pressure in the first pilot chamber 96 and the piston left chamber 108, which communicate with each other, rises.

When the air pressure in the piston left chamber 108 increases, the piston portion 104 of the pilot valve element 100 moves rightward within the cylinder portion 92g of the movable valve element 88 because the piston right chamber 110 is connected to the discharge port 26. As the pilot valve member 100 moves rightward relative to the movable valve member 88, the sixth radial hole 92f of the movable valve member 88 communicates with the fifth annular gap 114e, as shown in FIG. 19. Thereby, the first pilot chamber 96 and the piston left chamber 108 are connected to the second pilot chamber 98, and air at the primary pressure is supplied to the first pilot chamber 96 and the piston left chamber 108 via the second pilot chamber 98.

When air at a primary pressure is supplied to first pilot chamber 96, a force biasing movable valve element 88 to the right acts on movable valve element 88. The movable valve element 88 moves rightward as a result of the biasing force biasing the movable valve element 88 leftward beyond the biasing force of the air at the primary pressure in the second pilot chamber 98. In this manner, the movable valve element 88 is disengaged from the rest state at the intermediate position. Thereby, the second drive chamber connection opening 80d is connected to the supply opening 80c, and the first drive chamber connection opening 80b is connected to the first discharge opening 80 a. As a result, air from the supply port 22 is supplied to the second drive chamber 50b, and air in the first drive chamber 50a is discharged from the discharge port 26. The first and second pistons 42, 46 are driven to the left.

As can be understood from the above description, the air at the primary pressure supplied to the supply port 22 allows the movable valve element 88 stopped at the intermediate position to be disengaged from the stationary state at the intermediate position regardless of the position of the pilot valve element 100 relative to the movable valve element 88.

According to the supercharger 10 of this embodiment, the movable valve element 88 is driven by the air pressure in the first pilot chamber 96 and the second pilot chamber 98. Therefore, when the supercharger 10 is in use (i.e., when air is supplied to the supply port 22), the pilot switching valve 78 does not stop at the neutral position. Further, since the pilot valve element 100 is provided inside the movable valve element 88, the entire supercharger can be made compact. Further, since the movable valve element 88 is driven by air pressure, there is no limitation on the installation direction of the volume booster 10, although the movement of the movable valve element 88 may be affected by its weight depending on the installation direction of the volume booster 10.

Although air (compressed air) is used as the compressible fluid in this embodiment, any other gas may be used.

The supercharger according to the present invention is not particularly limited to the above-described embodiments, and may of course have various structures without departing from the scope of the present invention.