Hydraulic Rotating Machinery

Abstract

To provide a hydraulic rotary machine that can reduce pressure pulsation in a wide range.SOLUTION: A hydraulic rotary machine 1 according to an embodiment comprises a valve plate 6 in which a first port 61 and a second port 62 are formed, and a valve block 7 fitted with the valve plate 6, and in which a first flow passage 71 communicating with the first port 61 and a second flow passage 72 communicating with the second port 62 are formed. In the valve block 7, a housing chamber 73 is formed so as to be located on the first flow passage 71. In addition, the hydraulic rotary machine 1 comprises a metal pipe 8 arranged in the housing chamber 73, constituting a portion of the first flow passage 71, and elastically deformable outward in a radial direction.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to hydraulic rotary machines. [Background technology]

[0002] Conventionally, hydraulic rotary machines such as axial piston pumps and axial piston motors have been known. This hydraulic rotary machine includes a valve plate in which arc-shaped first and second ports are formed, and a cylinder block that slides with the valve plate. A plurality of cylinder bores are formed in the cylinder block, and a plurality of pistons are inserted into each of the cylinder bores. As the cylinder block rotates, some of the cylinder bores communicate with the first port, and the other several communicate with the second port.

[0003] If the hydraulic rotating machine is a hydraulic pump that rotates in one direction, one of the first and second ports is the suction port and the other is the discharge port. If the hydraulic rotating machine is a hydraulic pump that rotates in both directions, the first port may be the suction port and the second port may be the discharge port, or the second port may be the suction port and the first port may be the discharge port, depending on the direction of rotation. If the hydraulic rotating machine is a hydraulic motor, the first port may be the inlet port and the second port may be the outlet port, or the second port may be the inlet port and the first port may be the outlet port, depending on the direction of rotation.

[0004] For example, Patent Document 1 discloses a hydraulic pump that rotates in one direction, has a valve plate formed with an intake port and a discharge port, and has a valve block (part of the pump casing in Patent Document 1) to which the valve plate is attached, in which an intake passage communicating with the intake port and a discharge passage communicating with the discharge port are formed. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2016-109025 A Summary of the Invention [Problem to be solved by the invention]

[0006] Incidentally, when the hydraulic rotating machine is a hydraulic pump, pulsation occurs in the discharge pressure (high-pressure side pressure) immediately after each cylinder bore communicates with the high-pressure side discharge port, which is one of the first and second ports. Such pulsation in the discharge pressure causes vibration and noise in the hydraulic pump and the piping connected to the hydraulic pump, so it is desirable to reduce the pulsation in the discharge pressure.

[0007] In addition, when the hydraulic rotating machine is a hydraulic motor, pulsation occurs in the inlet pressure (high-pressure side pressure) immediately after each cylinder bore communicates with the high-pressure side inlet port, which is one of the first and second ports. Therefore, it is desirable to reduce the pulsation of the inlet pressure.

[0008] In the hydraulic pump disclosed in Patent Document 1, in order to reduce pulsation of the discharge pressure, a resonance chamber is formed in a regulator casing attached to a pump casing, and this resonance chamber is connected to the discharge passage by a communication passage. The resonance chamber and the communication passage constitute a Helmholtz resonator.

[0009] However, with such a configuration, it is only possible to reduce pressure pulsations near the resonance frequency that corresponds to the volume of the resonance chamber.

[0010] SUMMARY OF THE PRESENT EMBODIMENTS Accordingly, an object of the present invention is to provide a hydraulic rotating machine capable of reducing pressure pulsations over a wide range. [Means for solving the problem]

[0011] In order to solve the above-mentioned problems, a hydraulic rotary machine according to one aspect of the present invention comprises: a valve plate in which a first port and a second port are formed; and a cylinder block in which a plurality of pistons are inserted into a plurality of cylinder bores and which slides against the valve plate, so that some of the plurality of cylinder bores communicate with the first port and some of the cylinder bores communicate with the second port as the cylinder block rotates; a valve block to which the valve plate is attached, in which a first flow passage communicating with the first port and a second flow passage communicating with the second port are formed; and a metal tube that is arranged in a housing chamber formed in the valve block so as to be located above the first flow passage, which constitutes a part of the first flow passage and is capable of elastic deformation radially outward.

[0012] According to another aspect of the present invention, there is provided a hydraulic rotary machine comprising: a valve plate having a first port and a second port formed therein; and a cylinder block having a plurality of cylinder bores into which a plurality of pistons are inserted, the cylinder block sliding against the valve plate, wherein some of the plurality of cylinder bores communicate with the first port and some of the cylinder bores communicate with the second port as the cylinder block rotates; a valve block to which the valve plate is attached, the valve block being formed with a first flow passage communicating with the first port and a second flow passage communicating with the second port; an external block attached to the valve block and formed with an external flow passage communicating with the first flow passage; and a metal tube that is arranged within a housing chamber formed in the external block so as to be positioned above the external flow passage, the metal tube constituting a part of the external flow passage and capable of elastic deformation radially outward.

[0013] According to yet another aspect of the present invention, there is provided a hydraulic rotary machine comprising: a valve plate having a first port and a second port formed therein; and a cylinder block having a plurality of cylinder bores into which a plurality of pistons are inserted, the cylinder block sliding against the valve plate, wherein some of the plurality of cylinder bores communicate with the first port and some of the cylinder bores communicate with the second port as the cylinder block rotates; a valve block to which the valve plate is attached, the valve block having a first flow passage communicating with the first port and a second flow passage communicating with the second port formed therein; and a metal tube arranged within a chamber formed in the valve block at a position away from the first flow passage, the interior of which communicates with the first flow passage and which is capable of elastic deformation radially outward.

[0014] According to the above configuration, the metal tube can be elastically deformed so as to expand or contract in diameter. Therefore, in the case where the first port is the high pressure side and pulsation occurs in the high pressure side pressure immediately after each cylinder bore is connected to the first port, the metal tube vibrates in response to the pulsation. More specifically, when the pressure rises, the metal tube expands in diameter, and when the pressure drops, the metal tube contracts in diameter. This makes it possible to reduce the pulsation of the high pressure side pressure. Moreover, the vibration frequency range in which the metal tube can vibrate due to the volume change is wide enough to include various vibration modes in which the cross section undulates (a part of the circumferential direction is deformed radially outward and another part of the circumferential direction is deformed radially inward) in addition to the vibration mode in which the cross section expands or contracts as a whole while maintaining a similar shape, so that a wide range of pressure pulsation can be reduced. In particular, when the metal tube constitutes a part of the first flow path, the valve block can be made smaller than when the metal tube is arranged in a place other than the first flow path. Effect of the Invention

[0015] According to the present invention, pressure pulsation can be reduced over a wide range. [Brief description of the drawings]

[0016] [Figure 1]1 is a cross-sectional view of a hydraulic rotary machine according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a front view of the valve plate and the valve block, with a portion of the valve block shown in cross section. [Diagram 3] FIG. 3 is a cross-sectional view taken along line III-III in FIG. [Figure 4] FIG. 3 is an enlarged view of a main part of FIG. 2. [Diagram 5] FIG. 4 is a cross-sectional view of a valve plate and a valve block in a hydraulic rotary machine according to a first modified example. [Figure 6] FIG. 11 is an enlarged view of a main portion of a hydraulic rotating machine according to a second modified example. [Figure 7] FIG. 11 is an enlarged view of a main portion of a hydraulic rotating machine according to a third modified example. [Figure 8] FIG. 13 is an enlarged view of a main portion of a hydraulic rotating machine according to a fourth modified example. [Figure 9] FIG. 13 is an enlarged view of a main portion of a hydraulic rotating machine according to a fifth modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Fig. 1 shows a hydraulic rotating machine 1 according to one embodiment of the present invention. In this embodiment, the hydraulic rotating machine 1 is a hydraulic pump (axial piston pump) that rotates in one direction. In this embodiment, the hydraulic pump is a swash plate pump. However, the hydraulic pump may be a bent axis pump.

[0018] Specifically, the hydraulic rotating machine 1 includes a rotating shaft 11, a container-shaped casing 15 penetrated by the rotating shaft 11, and a valve block 7 that closes an opening of the casing 15. One end of the rotating shaft 11 located outside the casing 15 is connected to a prime mover (an engine or an electric motor) (not shown).

[0019] The casing 15 holds a bearing 12 that rotatably supports the middle of the rotating shaft 11, and the valve block 7 holds a bearing 13 that rotatably supports the other end of the rotating shaft 11. For ease of explanation, the axial direction of the rotating shaft 11 will be referred to as the front-rear direction (one end side is the front and the other end side is the rear) below.

[0020] A valve plate 6, a cylinder block 2, and a swash plate 5 are arranged in a space surrounded by the casing 15 and the valve block 7. The valve plate 6, the cylinder block 2, and the swash plate 5 are penetrated by a rotating shaft 11.

[0021] The valve plate 6 is attached to the front surface of the valve block 7. As shown in Fig. 2, the valve plate 6 is formed with a first port 61 and a second port 62 each having an arc shape. In this embodiment, as described above, the hydraulic rotating machine 1 is a hydraulic pump that rotates in one direction, so the first port 61 is a discharge port and the second port 62 is a suction port. Although not shown in the drawings, the valve plate 6 may have another port formed in at least one of the portions between the first port 61 and the second port 62.

[0022] The rotating shaft 11 rotates counterclockwise in Fig. 2. In the rotation direction of the rotating shaft 11, a surface located on the communication end side of the first port 61 which is a discharge port and on the communication start side of the second port 62 which is a suction port is a first blocking surface 63, and a surface located on the communication end side of the second port 62 and on the communication start side of the first port 61 is a second blocking surface 64.

[0023] The cylinder block 2 is fixed to the rotating shaft 11 and slides against the valve plate 6. The cylinder block 2 is formed with a plurality of cylinder bores 21 that open forward, and a plurality of pistons 3 are inserted into each of the cylinder bores 21.

[0024] Furthermore, the cylinder block 2 is formed with cylinder ports 22 for communicating each of the cylinder bores 21 with the first port 61 or the second port 62. As the cylinder block 2 rotates, some of the cylinder bores 21 communicate with the first port 61 through the corresponding cylinder ports 22, and some of the cylinder bores 21 communicate with the second port 62 through the corresponding cylinder ports 22.

[0025] The swash plate 5 has a sliding surface that is parallel to the direction in which the first port 61 and the second port 62 move away from each other (hereinafter, referred to as the left-right direction). When viewed from the left-right direction, the sliding surface of the swash plate 5 is inclined so that the sliding surface approaches a first blocking surface 63 of the valve plate 6 and moves away from a second blocking surface 64 of the valve plate 6. The swash plate 5 is supported by a support (not shown) provided on the casing 15.

[0026] A shoe 4 that slides on the sliding surface of the swash plate 5 is attached to the tip of each of the pistons 3. The shoe 4 is pressed by a pressing member (not shown) so that the shoe 4 is kept in contact with the sliding surface of the swash plate 5.

[0027] 2 and 3, the valve block 7 is formed with a first flow passage 71 communicating with the first port 61 of the valve plate 6, and a second flow passage 72 communicating with the second port 62. As described above, the first port 61 is the discharge port, and the second port 62 is the suction port, so that the first flow passage 71 is a discharge passage, and the second flow passage 72 is a suction passage. The upstream end of the second flow passage 72 is connected to a tank by piping (not shown), and the downstream end of the first flow passage 71 is connected to hydraulic equipment such as a hydraulic actuator or a control valve by piping (not shown).

[0028] In this embodiment, the first flow path 71 and the second flow path 72 open to the side surface of the valve block 7. In the illustrated example, the first flow path 71 and the second flow path 72 extend rearward from the front surface and then bend 90 degrees to the left or right.

[0029] Furthermore, in this embodiment, a housing chamber 73 is formed in the valve block 7 so as to be located above the first flow passage 71. A metal tube 8 that constitutes a part of the first flow passage 71 is disposed in the housing chamber 73. A space is provided in the housing chamber 73 to allow elastic deformation of the metal tube 8 in the radially outward direction.

[0030] 4, in this embodiment, the metal pipe 8 includes a cylindrical portion 81 and a pair of flanges 82, 83 protruding radially outward from both ends of the cylindrical portion 81. The flanges 82, 83 form both ends of the metal pipe 8.

[0031] On the other hand, the accommodating chamber 73 includes a peripheral surface 73a surrounding the metal pipe 8, a first annular wall surface 73b facing one end face of the metal pipe 8 (one side of the flange 82), and a second annular wall surface 73c facing the other end face of the metal pipe 8 (one side of the flange 83).

[0032] An ordinary pressure chamber 75 is formed between the outer circumferential surface of the metal tube 8 and the circumferential surface 73a of the accommodation chamber 73. This ordinary pressure chamber 75 is a space that allows the above-mentioned metal tube 8 to elastically deform radially outward. In this embodiment, the ordinary pressure chamber 75 is filled with working fluid. This working fluid has leaked from the first flow path 71 through a gap between the first wall surface 73b and one end face of the metal tube 8 and / or a gap between the second wall surface 73c and the other end face of the metal tube 8.

[0033] A drain passage 74 is formed in the valve block 7, extending from the normal pressure chamber 75 to the side surface. The opening of the drain passage 74 on the side surface of the valve block 7 is connected to a tank by a pipe (not shown). This configuration allows the working fluid to flow out of the normal pressure chamber 75 and into the normal pressure chamber 75 (i.e., the volume of the normal pressure chamber 75 changes).

[0034] In the hydraulic rotary machine 1 configured as described above, the metal tube 8 can be elastically deformed so as to expand or contract in diameter. Therefore, if pulsation occurs in the discharge pressure (high-pressure side pressure) immediately after each cylinder bore 21 communicates with the first port 61, which is the high-pressure side discharge port, the metal tube 8 vibrates in response to the pulsation. More specifically, when the pressure increases, the metal tube 8 expands in diameter, and when the pressure decreases, the metal tube 8 contracts in diameter. This makes it possible to reduce the pulsation of the discharge pressure (high-pressure side pressure). Moreover, the vibration frequency range in which the metal tube 8 can vibrate due to a change in volume is wide enough to include various vibration modes in which the cross section undulates (a part of the circumferential direction deforms radially outward and another part of the circumferential direction deforms radially inward) in addition to a vibration mode in which the cross section expands or contracts as a whole while maintaining a similar shape, so that a wide range of pressure pulsation can be reduced.

[0035] In addition, in this embodiment, since the accommodation chamber 73 includes the first wall surface 73b and the second wall surface 73c that face both end surfaces of the metal tube 8, the metal tube 8 can be sandwiched and held between the first wall surface 73b and the second wall surface 73c.

[0036] (Modification) The present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the gist of the present invention.

[0037] For example, the accommodation chamber 73 does not necessarily have to be located above the first flow path 71. For example, as in a first modified example shown in Fig. 5, the accommodation chamber 73 may be formed at a position away from the first flow path 71. In this case, a communication passage 78 that connects the inside of the metal pipe 8 with the first flow path 71 is formed in the valve block 7. However, when the metal pipe 8 constitutes a part of the first flow path 71 as in the above embodiment, the valve block 7 can be made smaller in size than when the metal pipe 8 is disposed at a location other than the first flow path 71.

[0038] The normal pressure chamber 75 may be filled with air, but in this case, if the hydraulic rotating machine 1 is not operated for a long period of time, air may enter the first flow path 71 from the normal pressure chamber 75. In contrast, if the normal pressure chamber 75 is filled with working fluid as in the above embodiment, such air intrusion can be prevented.

[0039] 6 , the above-mentioned metal tube 8 may be disposed as a first metal tube 8 in the accommodation chamber 73, and a second metal tube 9 surrounding the first metal tube 8 may be disposed. The second metal tube 9 is configured similarly to the first metal tube 8. Specifically, the second metal tube 9 includes a cylindrical portion 91 and a pair of flanges 92, 93 protruding radially outward from both ends of the cylindrical portion 91. The flanges 92, 93 constitute both ends of the second metal tube 9.

[0040] In the configuration shown in FIG. 6, the first wall surface 73b of the accommodation chamber 73 faces not only one end face of the first metal tube 8 but also one end face of the second metal tube 9, and the second wall surface 73c faces not only the other end face of the first metal tube 8 but also the other end face of the second metal tube 9. An intermediate chamber 76 is formed between the outer circumferential surface of the first metal tube 8 and the inner circumferential surface of the second metal tube 9, and a normal pressure chamber 77 is formed between the outer circumferential surface of the second metal tube 9 and the circumferential surface 73a of the accommodation chamber 73. The intermediate chamber 76 is a space that allows the first metal tube 8 to elastically deform outward in the radial direction, and the normal pressure chamber 77 is a space that allows the second metal tube 9 to elastically deform outward in the radial direction. The drain passage 74 extends from the normal pressure chamber 77 to the side surface of the valve block 7.

[0041] The intermediate chamber 76, like the atmospheric pressure chamber 75 in the above embodiment, is filled with working fluid that has leaked from the first flow path 71 through the gap between the first wall surface 73b and one end face of the first metal tube 8 and / or the gap between the second wall surface 73c and the other end face of the first metal tube 8.

[0042] The normal pressure chamber 77 is filled with working fluid that has leaked from the first flow path 71 through the gap between the first wall surface 73b and one end face of the first metal tube 8 and the gap between the first wall surface 73b and one end face of the second metal tube 9, and / or through the gap between the second wall surface 73c and the other end face of the first metal tube 8 and the gap between the second wall surface 73c and the other end face of the second metal tube 9.

[0043] 6, the metal tube is arranged in two layers, so the pressure difference acting on each metal tube is small. This makes it possible to use metal tubes that are more elastically deformable than when the metal tube is single-layered, and it is possible to reduce pressure pulsation over a wider range.

[0044] As the metal tube to be placed in the accommodation chamber 73, other than the metal tube 8 having the cylindrical portion 81 and the pair of flanges 82, 83, metal tubes of various shapes can be used.

[0045] For example, as in a third modified example shown in Fig. 7, a metal tube 8A having a constant thickness over its entire length may be placed in the accommodation chamber 73. In Fig. 7, a ring-shaped member 9 is placed between both ends of the outer circumferential surface of the metal tube 8A and both ends of the circumferential surface 73a of the accommodation chamber 73 to keep the metal tube 8A in the center of the accommodation chamber 73.

[0046] Alternatively, as in a fourth modified example shown in Figure 8, a metal tube 8B including a cylindrical portion 81 and a protrusion 84 protruding radially outward from the center of the cylindrical portion 81 and abutting against the peripheral surface 73a of the storage chamber 73 may be arranged within the storage chamber 73.

[0047] Furthermore, the accommodation chamber 75 does not necessarily have to be formed in the valve block 7. For example, as in a fifth modified example shown in Fig. 9, an external block 7A having an external flow path 71A communicating with the first flow path 71 formed therein may be attached to the valve block 7, and the accommodation chamber 73 may be formed in the external block 7A so as to be located above the external flow path 71A. The metal tube 8 disposed in the accommodation chamber 73 constitutes a part of the external flow path 71A.

[0048] 9, the external block 7A is directly attached to the valve block 7, but the external block 7A may be attached to the valve block 7 via a pipe such that a pipe is interposed between the external block 7A and the valve block 7. In addition, in the accommodation chamber 73 formed in the external block 7A, a metal pipe 8 may be disposed as a first metal pipe 8, and a second metal pipe 9 surrounding the first metal pipe 8 may be disposed, similarly to FIG.

[0049] Furthermore, in the configuration shown in FIG. 9, similarly to FIG. 4, the normal pressure chamber 75 between the outer peripheral surface of the metal tube 8 and the peripheral surface 73a of the accommodation chamber 73 may be filled with working fluid leaking from the external flow path 71A through the gap between the first wall surface 73b and one end face of the first metal tube 8 and / or the gap between the second wall surface 73c and the other end face of the first metal tube 8.

[0050] Furthermore, the hydraulic rotating machine 1 may be a hydraulic pump that rotates in both directions, or may be a hydraulic motor. In this case, two accommodation chambers 73 may be formed in the valve block 7, and two metal tubes 8 may be disposed in these accommodation chambers 73, respectively. One metal tube 8 may form a part of the first flow path 71, or the interior of one metal tube 8 may communicate with the first flow path 71, and the other metal tube 8 may form a part of the second flow path 72, or the interior of the other metal tube 8 may communicate with the second flow path 72.

[0051] (summary) A hydraulic rotary machine according to one aspect of the present invention is characterized in that it comprises: a valve plate in which a first port and a second port are formed; and a cylinder block in which a plurality of pistons are inserted into a plurality of cylinder bores that slide against the valve plate, so that some of the plurality of cylinder bores communicate with the first port and some of the cylinder bores communicate with the second port as the cylinder block rotates; a valve block to which the valve plate is attached, in which a first flow passage communicating with the first port and a second flow passage communicating with the second port are formed; and a metal tube that is arranged in a housing chamber formed in the valve block so as to be positioned above the first flow passage, constituting a part of the first flow passage and capable of elastic deformation radially outward.

[0052] According to another aspect of the present invention, there is provided a hydraulic rotary machine comprising: a valve plate having a first port and a second port formed therein; and a cylinder block having a plurality of cylinder bores into which a plurality of pistons are inserted, the cylinder block sliding against the valve plate, wherein some of the plurality of cylinder bores communicate with the first port and some of the cylinder bores communicate with the second port as the cylinder block rotates; a valve block to which the valve plate is attached, the valve block having a first flow passage communicating with the first port and a second flow passage communicating with the second port formed therein; an external block attached to the valve block, the external flow passage communicating with the first flow passage formed therein; and a metal tube which is disposed within a housing chamber formed in the external block so as to be positioned above the external flow passage, the metal tube constituting a part of the external flow passage and capable of elastic deformation radially outward.

[0053] According to yet another aspect of the present invention, there is provided a hydraulic rotary machine comprising: a valve plate having a first port and a second port formed therein; and a cylinder block having a plurality of cylinder bores into which a plurality of pistons are inserted, the cylinder block sliding against the valve plate, wherein some of the plurality of cylinder bores communicate with the first port and some of the cylinder bores communicate with the second port as the cylinder block rotates; a valve block to which the valve plate is attached, the valve block having a first flow passage communicating with the first port and a second flow passage communicating with the second port formed therein; and a metal tube arranged within a chamber formed in the valve block at a position away from the first flow passage, the interior of which communicates with the first flow passage and which is capable of elastic deformation radially outward.

[0054] According to the above configuration, the metal tube can be elastically deformed so as to expand or contract in diameter. Therefore, in the case where the first port is the high pressure side and pulsation occurs in the high pressure side pressure immediately after each cylinder bore is connected to the first port, the metal tube vibrates in response to the pulsation. More specifically, when the pressure rises, the metal tube expands in diameter, and when the pressure drops, the metal tube contracts in diameter. This makes it possible to reduce the pulsation of the high pressure side pressure. Moreover, the vibration frequency range in which the metal tube can vibrate due to the volume change is wide enough to include various vibration modes in which the cross section undulates (a part of the circumferential direction is deformed radially outward and another part of the circumferential direction is deformed radially inward) in addition to the vibration mode in which the cross section expands or contracts as a whole while maintaining a similar shape, so that a wide range of pressure pulsation can be reduced. In particular, when the metal tube constitutes a part of the first flow path, the valve block can be made smaller than when the metal tube is arranged in a place other than the first flow path.

[0055] For example, the metal tube may include a cylindrical portion and a pair of flanges protruding radially outward from both ends of the cylindrical portion.

[0056] The housing chamber may include a peripheral surface surrounding the metal pipe, a first wall surface facing one end surface of the metal pipe, and a second wall surface facing the other end surface of the metal pipe. With this configuration, the metal pipe can be sandwiched and held between the first wall surface and the second wall surface.

[0057] Between the outer circumferential surface of the metal pipe and the outer circumferential surface of the accommodation chamber, an atmospheric pressure chamber, which is the space that allows elastic deformation of the metal pipe in the radially outward direction, may be formed, and this atmospheric pressure chamber may be filled with working fluid leaked from the first flow path or the external flow path through a gap between the first wall surface and one end face of the metal pipe and / or a gap between the second wall surface and the other end face of the metal pipe. The atmospheric pressure chamber may be filled with air, but in this case, there is a risk that air will enter the first flow path from the atmospheric pressure chamber if the hydraulic rotating machine is not operated for a long period of time. In contrast, if the atmospheric pressure chamber is filled with working fluid, such air intrusion can be prevented.

[0058] The metal tube is a first metal tube, and the hydraulic rotary machine further comprises a second metal tube disposed in the accommodation chamber surrounding the first metal tube, the first wall surface of the accommodation chamber also faces one end surface of the second metal tube, the second wall surface also faces the other end surface of the second metal tube, and an intermediate chamber is formed between an outer circumferential surface of the first metal tube and an inner circumferential surface of the second metal tube, the intermediate chamber being the space that allows elastic deformation of the first metal tube in the radially outward direction, and the intermediate chamber is provided from the first flow path or the external flow path to a gap between the first wall surface and one end surface of the first metal tube and / or a gap between the second wall surface and the first metal tube The second metal tube is filled with working fluid leaking through a gap between the first wall surface and the other end face of the first metal tube, and a normal pressure chamber, which is a space that allows elastic deformation of the second metal tube in the radial outward direction, is formed between the outer circumferential surface of the second metal tube and the circumferential surface of the accommodation chamber, and the normal pressure chamber may be filled with working fluid leaking from the first flow path or the external flow path through a gap between the first wall surface and one end face of the first metal tube and a gap between the first wall surface and one end face of the second metal tube, and / or a gap between the second wall surface and the other end face of the first metal tube and a gap between the second wall surface and the other end face of the second metal tube. According to this configuration, the metal tubes are arranged in a double layer, so that the pressure difference acting on one metal tube is small. Therefore, it is possible to use a metal tube that is more easily elastically deformed than when a single metal tube is used, and pressure pulsation can be reduced over a wider range.

[0059] For example, the second metal tube may include a cylindrical portion and a pair of flanges protruding radially outward from both ends of the cylindrical portion.

[0060] For example, the hydraulic rotating machine may be a hydraulic pump, the first port may be a discharge port, the second port may be a suction port, the first flow path may be a discharge passage, and the second flow path may be a suction passage. [Explanation of symbols]

[0061] 1. Hydraulic Rotating Machinery 2 Cylinder block 21 Cylinder bore 3 Piston 6 Valve Plate 61 Port 1 62 Second Port 7 Valve Block 71 First Channel 72 Second Stream 73 Containment Room 73a Circumferential surface 73b 1st wall 73c 2nd wall 75 Normal pressure room (space) 76 Intermediate Room (Space) 77 Normal pressure room (space) 7A External Block 71A External flow path 8 Metal pipe, first metal pipe 81 Cylindrical part 82,83 Flange 9 Second metal pipe 91 Cylindrical part 92,93 Flange

Claims

1. a valve plate having a first port and a second port formed therein; a cylinder block having a plurality of cylinder bores into which a plurality of pistons are inserted, the cylinder block sliding against the valve plate, some of the cylinder bores communicating with the first port and some of the cylinder bores communicating with the second port as the cylinder block rotates; a valve block to which the valve plate is attached, the valve block having a first passage communicating with the first port and a second passage communicating with the second port; a metal tube that is disposed in a receiving chamber formed in the valve block so as to be located above the first flow passage, that constitutes a part of the first flow passage, and that is capable of elastic deformation in a radially outward direction; The metal tube includes a cylindrical portion and a pair of flanges protruding radially outward from both ends of the cylindrical portion.

2. a valve plate having a first port and a second port formed therein; a cylinder block having a plurality of cylinder bores into which a plurality of pistons are inserted, the cylinder block sliding against the valve plate, some of the cylinder bores communicating with the first port and some of the cylinder bores communicating with the second port as the cylinder block rotates; a valve block to which the valve plate is attached, the valve block having a first passage communicating with the first port and a second passage communicating with the second port; an external block attached to the valve block and having an external flow passage formed therein and communicating with the first flow passage; a metal tube that is disposed in a receiving chamber formed in the external block so as to be positioned above the external flow passage, that constitutes a part of the external flow passage, and that is capable of elastic deformation in a radially outward direction; The metal tube includes a cylindrical portion and a pair of flanges protruding radially outward from both ends of the cylindrical portion.

3. a valve plate having a first port and a second port formed therein; a cylinder block having a plurality of cylinder bores into which a plurality of pistons are inserted, the cylinder block sliding against the valve plate, some of the cylinder bores communicating with the first port and some of the cylinder bores communicating with the second port as the cylinder block rotates; a valve block to which the valve plate is attached, the valve block having a first passage communicating with the first port and a second passage communicating with the second port; a metal tube disposed in a receiving chamber formed in the valve block at a position away from the first flow path, the metal tube having an interior that communicates with the first flow path and that is capable of elastic deformation in a radially outward direction, The metal tube includes a cylindrical portion and a pair of flanges protruding radially outward from both ends of the cylindrical portion.

4. 4. The hydraulic rotary machine according to claim 1, wherein a space that allows elastic deformation of the metal tube in a radially outward direction is provided within the accommodation chamber.

5. 5. The hydraulic rotating machine according to claim 4, wherein the accommodation chamber includes a peripheral surface surrounding the metal pipe, a first wall surface facing one end surface of the metal pipe, and a second wall surface facing the other end surface of the metal pipe.

6. 6. The hydraulic rotating machine according to claim 5, wherein an atmospheric pressure chamber, which is the space allowing elastic deformation of the metal tube in a radially outward direction, is formed between an outer circumferential surface of the metal tube and a peripheral surface of the accommodation chamber, and this atmospheric pressure chamber is filled with working fluid leaking through a gap between the first wall surface and one end face of the metal tube and / or a gap between the second wall surface and the other end face of the metal tube.

7. the metal tube is a first metal tube, a second metal tube disposed in the containing chamber and surrounding the first metal tube; the first wall surface of the accommodation chamber also faces one end surface of the second metal pipe, and the second wall surface also faces the other end surface of the second metal pipe, an intermediate chamber, which is the space that allows elastic deformation of the first metal tube in a radially outward direction, is formed between an outer circumferential surface of the first metal tube and an inner circumferential surface of the second metal tube, and this intermediate chamber is filled with working fluid leaking through a gap between the first wall surface and one end face of the first metal tube and / or a gap between the second wall surface and the other end face of the first metal tube, 6. The hydraulic rotating machine according to claim 5, wherein an atmospheric pressure chamber, which is a space that allows elastic deformation of the second metal tube in a radially outward direction, is formed between an outer circumferential surface of the second metal tube and a peripheral surface of the accommodation chamber, and this atmospheric pressure chamber is filled with working fluid leaking through a gap between the first wall surface and one end face of the first metal tube and a gap between the first wall surface and one end face of the second metal tube, and / or a gap between the second wall surface and the other end face of the first metal tube and a gap between the second wall surface and the other end face of the second metal tube.

8. The hydraulic rotary machine according to claim 7 , wherein the second metal tube includes a cylindrical portion and a pair of flanges protruding radially outward from both ends of the cylindrical portion.

9. 4. The hydraulic rotating machine according to claim 1, wherein a normal pressure chamber, which is a space that allows elastic deformation of the metal pipe in a radially outward direction, is formed between an outer circumferential surface of the metal pipe and a peripheral surface of the accommodation chamber, and the normal pressure chamber is in communication with a drain passage.

10. the hydraulic rotating machine being a hydraulic pump; The first port is a discharge port and the second port is a suction port, The hydraulic rotary machine according to any one of claims 1 to 9, wherein the first flow path is a discharge path, and the second flow path is a suction path.

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