Compressor

Abstract

A compressor (10) comprises: a cylinder (21) that has a cylinder chamber (31); a piston (27) that reciprocates inside the cylinder (21); and a head cover (41) that closes an end surface of the cylinder (21), the head cover (41) having a flow path (51) having an inner section (52) that opens to the cylinder chamber (31) and an outer section (54) that is connected to the inner section (52) and opens to a side surface of the head cover (41).

Description

Compressor

[0001] The present invention relates to a compressor used to compress a fluid such as hydrogen.

[0002] A reciprocating compressor has been proposed in which the end face of the cylinder is blocked by a block, and the block has an intake valve and a discharge valve inside, with a gas inlet and outlet on the opposite side of the block from the compression chamber (Japanese Patent Laid-Open No. 2006-52709, hereinafter referred to as Patent Document 1).

[0003] When a flow passage is formed along the direction of piston movement, as in the block disclosed in Patent Document 1, the block may be deformed by the pressure in the compression chamber, causing excessive stress on the inner peripheral surface of the flow passage. Furthermore, the application of high pressure to the flow passage may cause excessive stress in a specific area. The present invention aims to provide a compressor that can prevent excessive stress in the flow passage, even when the flow passage connecting the cylinder chamber and the outside is exposed to high pressure.

[0004] A first aspect of the present invention is a compressor comprising: a cylinder having a cylinder chamber; a piston that reciprocates inside the cylinder; and a head cover that closes an end face of the cylinder, the head cover having a flow path including an inner section that opens into the cylinder chamber, and an outer section that is connected to the inner section and opens to a side surface of the head cover.

[0005] The cylinder chamber is a space where the fluid is compressed. A part of the head cover may be fitted inside the cylinder. The piston is driven by, for example, hydraulic or electric motor.

[0006] The flow passages are formed inside the head cover. The flow passages may include an intake passage and an exhaust passage. The intake passage and the exhaust passage may be provided separately. Increasing the number of flow passages can increase the flow rate. One end of each flow passage opens into the cylinder chamber, and the other end opens to a side surface of the head cover. The side surface of the head cover refers to the surface on each surface of the head cover that extends generally along the direction of piston movement.

[0007] Each flow passage extends in a different direction at one end and the other end. In each flow passage, the side that opens into the cylinder chamber is called the inner section. The side that opens into the side of the head cover is called the outer section. The bottoms of the inner section and the outer section are connected to each other.

[0008] The inner section may extend in any direction, or may extend at an angle relative to the direction of piston movement, and the outer section may extend perpendicular to the direction of piston movement or at an angle relative to the direction of piston movement.

[0009] According to the compressor of the present invention, even when the flow passage provided in the head cover is exposed to high pressure, it is possible to prevent excessive stress in the flow passage.

[0010] 1 is a perspective view of a compressor according to a first embodiment; a perspective view of the head cover of FIG. 1 turned upside down; a cross-sectional view taken along line I-I in FIG. 2; a cross-sectional view taken along line II-II in FIG. 2; an assembly diagram of FIG. 1; a perspective view of the head cover of a second embodiment; a perspective view showing the flow path of the head cover of FIG. 6; a perspective view of the head cover of a third embodiment; a cross-sectional view taken along line III-III in FIG. 8; a perspective view of the head cover of a fourth embodiment.

[0011] First Embodiment As shown in Fig. 1 , a compressor 10 of this embodiment includes a drive unit 11, a drive rod 17, a base plate 13, a piston 27, a cylinder 21, a jacket 23, a head cover 41, a tie rod 15, a joint 33, and a check valve 59. The piston 27 reciprocates inside the cylinder 21. A seal 29 is disposed on the outer circumferential surface of the piston 27. The drive unit 11 serves as a power source for the reciprocating motion of the piston 27. The drive unit 11 is powered by hydraulic pressure or the like. The piston 27 and the drive unit 11 are connected via a drive rod 17. The cylinder 21 and the jacket 23 are placed on the surface of the base plate 13.

[0012] The cylinder 21 is cylindrical. The jacket 23 is cylindrical and surrounds the outside of the cylinder 21. The cylinder 21 and the jacket 23 are arranged concentrically.

[0013] The head cover 41 has a flange portion 43 and a fitting portion 45. The flange portion 43 closes the end faces of the cylinder 21 and the jacket 23. The fitting portion 45 protrudes from one end face side of the flange portion 43. The fitting portion 45 is fitted into the inner circumferential surface of the cylinder 21. The space defined by the cylinder 21, the piston 27, and the head cover 41 is the cylinder chamber 31. The fluid to be compressed is, for example, hydrogen.

[0014] A seal 47 is disposed in the fitting portion 45. The seal 47 seals the gap between the cylinder 21 and the head cover 41. Coolant is supplied between the cylinder 21 and the jacket 23. The jacket 23 has a connection port 25. A fitting 33 is attached to the connection port 25. The fitting 33 serves as an inlet and an outlet for the coolant.

[0015] The head cover 41 has a flow path 51. The flow path 51 has an inner section 52 and an outer section 54. The inner section 52 opens to the cylinder chamber 31. The outer section 54 opens to the side surface of the head cover 41. The bottoms of the inner section 52 and the outer section 54 are connected to each other. The outer section 54 has a connection port 56 at its end. The connection port 56 is located on the side surface of the head cover 41. A check valve 59 or the like may be attached to the connection port 56.

[0016] The inner section 52 extends at an angle relative to the direction of movement of the piston 27. The outer section 54 extends perpendicular to the direction of movement of the piston 27. The angle θ formed by the inner section 52 and the outer section 54 is an obtuse angle exceeding 90 degrees. The head cover 41 of this embodiment has two flow paths 51 to separate the intake and exhaust of fluid.

[0017] The tie rod 15 extends in a direction connecting the base plate 13 and the head cover 41. One end of the tie rod 15 is integrated with the base plate 13. The other end of the tie rod 15 is inserted into a fixing hole 57 in the head cover 41. A nut 16 is screwed onto the tie rod 15 protruding from the fixing hole 57, and the head cover 41 is brought into close contact with the cylinder 21.

[0018] Figure 2 shows details of the head cover 41 in Figure 1. In Figure 2, the head cover 41 is turned upside down compared to Figure 1. The fitting portion 45 has a circular cross section that fits into the inner circumferential surface of the cylinder 21. Two flow paths 51 open on the end face of the fitting portion 45. The flange portion 43 is rectangular. The flow paths 51 open on the side surface of the flange portion 43.

[0019] Figure 3 is a cross-sectional view taken along line II in Figure 2. Figure 3 shows a cross-section of one of the two flow paths 51. An inner section 52 of the flow path 51 extends obliquely with respect to the end face of the fitting portion 45. A bottom surface 53 of the inner section 52 is hemispherical.

[0020] The outer section 54 extends parallel to the plane of the flange portion 43. The outer section 54 opens to the bottom surface 53 of the inner section 52. The angle θ between the inner section 52 and the outer section 54 is an obtuse angle. The outer section 54 has a smaller diameter than the inner section 52. Due to the difference in inner diameter between the outer section 54 and the inner section 52, the outer section 54 can easily open to the bottom surface 53 even if a dimensional error occurs during processing of the outer section 54.

[0021] Figure 4 is a cross-sectional view taken along line II-II in Figure 2. Figure 4 shows a cross-section of one of the two flow paths 51, which is different from the flow path 51 shown in Figure 3. The flow path 51 in Figure 4 is arranged by flipping the flow path 51 in Figure 3 left and right. The opening of the outer section 54 is located on the opposite side to that shown in Figure 3. The angle θ between the inner section 52 and the outer section 54 is an obtuse angle.

[0022] As shown in Figures 3 and 4, the angle between the inner section 52 and the outer section 54 is an obtuse angle. This reduces the sharpness of the edges formed at the intersections of the inner section 52 and the outer section 54. This effect increases as the inner section 52 and the outer section 54 approach a straight line. In this way, the sharpness of the edges formed at the intersections is reduced, thereby reducing stress acting on the flow path even under severe conditions such as when hydrogen is pressurized to ultra-high pressures. By making the bottom surface 53 of the inner section 52 a curved surface, pressure acts evenly across the entire bottom surface 53, reducing stress.

[0023] 5 is an assembly diagram of the compressor 10 shown in FIG. 1. The head cover 41 is fixed to the base plate 13 via tie rods 15. An inner section 52 of the flow passage 51 opens into the cylinder chamber 31. A check valve 59 is attached to the end of the outer section 54. The compressor 10 has the flow passage 51 serving as an intake passage and the flow passage 52 serving as a discharge passage.

[0024] A gap is formed between the cylinder 21 and the jacket 23. Coolant is supplied to this gap to cool the periphery of the cylinder chamber 31. A joint 33 is attached to the jacket 23. The joint 33 serves as an inlet and an outlet for the coolant.

[0025] Second Embodiment As shown in Fig. 6 , a head cover 141 of this embodiment has two flow paths 51. Each flow path 51 has one inner section 52 and two outer sections 54. The head cover 141 shown in Fig. 6 is oriented with the fitting portion 45 facing upward. The two outer sections 54 open to the bottom surface 53 of the inner section 52.

[0026] 7 shows one flow path 51 of the head cover 141 of FIG. 6. The bottom surface 53 of the inner section 52 of the flow path 51 is formed as a curved surface. Two outer sections 54 open to the bottom surface 53. The two outer sections 54 extend in directions perpendicular to each other. Each outer section 54 opens to a side surface of the flange portion 43.

[0027] 8 , in a head cover 241 of this embodiment, an outer section 54 of a flow path 51 extends obliquely. An inner section 52 of the flow path 51 extends in a direction perpendicular to the end face of the fitting portion 45. The angle between the inner section 52 and the outer section 54 is an obtuse angle.

[0028] Figure 9 is a cross-sectional view taken along line III-III in Figure 8. The bottom surface 53 of the inner section 52 is hemispherical. The outer section 54 extends obliquely downward from the side surface of the flange portion 43. The outer section 54 opens at the bottom surface 53 of the inner section 52.

[0029] As a modification of the third embodiment, the inner section 52 of the flow path 51 may be replaced with that of the first embodiment. In this case, the inner section 52 extends so as to be inclined with respect to the end face of the fitting portion 45. Therefore, the inner section 52 and the outer section 54 are arranged in a nearly straight line.

[0030] 10 , the flow path 51 of the head cover 341 of this embodiment has a curved section 55 between the inner section 52 and the outer section 54. The curved section 55 makes the inner circumferential surface of the flow path 51 smooth throughout. Therefore, even when the flow path 51 is exposed to high pressure, excessive stress on the inner circumferential surface can be suppressed. The shape, curvature, etc. of the curved section 55 may be determined arbitrarily.

[0031] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the gist of the present invention, and all technical matters included in the technical ideas described in the claims are the subject of the present invention. The above-described embodiments are preferred examples, but a person skilled in the art can realize various alternatives, modifications, variations, or improvements from the contents of the disclosure of this specification, and these are included in the technical scope described in the appended claims.

[0032] REFERENCE SIGNS LIST 10 Compressor 11 Drive section 13 Base plate 15 Tie rod 16 Nut 17 Drive rod 21 Cylinder 23 Jacket 25 Connection port 27 Piston 29 Seal 31 Cylinder chamber 33 Joint 41, 141, 241, 341 Head cover 43 Flange portion 45 Fitting portion 47 Seal 51 Flow path 52 Inner section 53 Bottom surface 54 Outer section 55 Curved section 56 Connection port 57 Fixing hole 59 Check valve

Claims

1. A compressor comprising: a cylinder having a cylinder chamber; a piston that reciprocates inside the cylinder; and a head cover that closes an end face of the cylinder, the head cover having a flow path including an inner section that opens into the cylinder chamber and an outer section that is connected to the inner section and opens to a side surface of the head cover.

2. The compressor according to claim 1, wherein the head cover has a plurality of the flow passages.

3. The compressor according to claim 1 or 2, wherein the angle formed between the inner section and the outer section is an obtuse angle.

4. A compressor according to any one of claims 1 to 3, wherein the flow path has a bottom surface formed by a curved surface, one of the inner section and the outer section has the bottom surface, and the other of the inner section and the outer section opens to the bottom surface.

5. A compressor according to any one of claims 1 to 3, wherein the inner section and the outer section have different inner diameters, the section with the larger inner diameter has a bottom surface formed by a curved surface, and the section with the smaller inner diameter opens onto the bottom surface.

6. A compressor according to any one of claims 1 to 3, wherein the flow path has a curved section between the inner section and the outer section.

7. A compressor according to claim 4 or 5, wherein the flow path has a plurality of the outer sections connected to one of the inner sections.

8. A compressor according to claim 4 or 5, wherein the bottom surface is hemispherical or has a parabolic cross section.

Images