JP7620484B2 - Hydraulic Rotating Machinery - Google Patents

Description

The present invention relates to a hydraulic rotating machine.

Hydraulic rotary machines such as axial piston pumps and axial piston motors are 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 against the valve plate. A number of cylinder bores are formed in the cylinder block, and a number of pistons are inserted into each of these cylinder bores. As the cylinder block rotates, some of the cylinder bores communicate with the first port, and some communicate with the second port.

When 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. When the hydraulic rotating machine is a hydraulic pump that rotates in both directions, depending on the direction of rotation, 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. Also, when the hydraulic rotating machine is a hydraulic motor, depending on the direction of rotation, 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.

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.

JP 2016-109025 A

However, 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 can cause 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.

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.

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 the pump casing, and this resonance chamber is connected to the discharge passage by a communication passage. The resonance chamber and the communication passage form a Helmholtz resonator.

However, this configuration can only reduce pressure pulsations near the resonance frequency that corresponds to the volume of the resonance chamber.

Therefore, the present invention aims to provide a hydraulic rotating machine that can reduce pressure pulsations over a wide range.

In order to solve the above problem, a hydraulic rotary machine according to one aspect of the present invention is characterized by comprising: a valve plate in which a first port and a second port are formed; a cylinder block in which a plurality of pistons are inserted into a plurality of cylinder bores that slide against the valve plate, and in which some of the plurality of cylinder bores communicate with the first port and some 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 path communicating with the first port and a second flow path communicating with the second port are formed; and a metal tube that is arranged in a housing formed in the valve block so as to be located above the first flow path, forms part of the first flow path, and is capable of elastic deformation radially outward.

In another aspect of the present invention, a hydraulic rotary machine includes a valve plate having a first port and a second port, 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 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 flow path communicating with the first port and a second flow path communicating with the second port, an external block attached to the valve block, the external flow path communicating with the first flow path, and a metal tube disposed in a chamber formed in the external block so as to be positioned above the external flow path, constituting a part of the external flow path and capable of elastic deformation radially outward.

A hydraulic rotary machine according to yet another 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, a cylinder block in which a plurality of pistons are inserted into a plurality of cylinder bores that slide against the valve plate, some of the cylinder bores communicate with the first port and some communicate with the second port as the cylinder block rotates, a valve block to which the valve plate is attached and in which a first flow path communicating with the first port and a second flow path communicating with the second port are formed, and a metal tube that is disposed in a chamber formed in the valve block at a position away from the first flow path, the interior of which communicates with the first flow path, and which is capable of elastic deformation radially outward.

According to the above configuration, the metal tube can be elastically deformed so as to expand or contract in diameter. Therefore, when 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 reduces the pulsation of the high pressure side pressure. Furthermore, the vibration frequency range in which the metal tube can vibrate due to volume change 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 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 placed in a place other than the first flow path.

The present invention can reduce pressure pulsations over a wide range.

1 is a cross-sectional view of a hydraulic rotary machine according to an embodiment of the present invention. 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. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. FIG. 3 is an enlarged view of a main part of FIG. 2 . 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. FIG. 11 is an enlarged view of a main portion of a hydraulic rotating machine according to a second modified example. FIG. 13 is an enlarged view of a main portion of a hydraulic rotating machine according to a third modified example. FIG. 13 is an enlarged view of a main portion of a hydraulic rotating machine according to a fourth modified example. FIG. 13 is an enlarged view of a main portion of a hydraulic rotating machine according to a fifth modified example.

Figure 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 also be a bent axis pump.

Specifically, the hydraulic rotating machine 1 includes a rotating shaft 11, a container-shaped casing 15 that is 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 (engine or electric motor) not shown.

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.

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

The valve plate 6 is attached to the front surface of the valve block 7. As shown in FIG. 2, the valve plate 6 has a first port 61 and a second port 62 formed in 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, 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.

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

The cylinder block 2 is fixed to the rotating shaft 11 and slides against the valve plate 6. The cylinder block 2 has multiple cylinder bores 21 that open forward, and multiple pistons 3 are inserted into each of these cylinder bores 21.

Furthermore, the cylinder block 2 is formed with cylinder ports 22 for connecting each of the cylinder bores 21 to 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.

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, 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 the first blocking surface 63 of the valve plate 6 and moves away from the 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.

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 described above. The shoe 4 is held down by a pressing member (not shown) so that it remains in contact with the sliding surface of the swash plate 5.

As shown in Figures 2 and 3, the valve block 7 is formed with a first flow path 71 that communicates with the first port 61 of the valve plate 6, and a second flow path 72 that communicates 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 the first flow path 71 is the discharge path, and the second flow path 72 is the suction path. The upstream end of the second flow path 72 is connected to a tank by piping (not shown), and the downstream end of the first flow path 71 is connected to hydraulic equipment such as a hydraulic actuator or a control valve by piping (not shown).

In this embodiment, the first flow path 71 and the second flow path 72 open to the side 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 face and then bend 90 degrees to the left or right.

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

In this embodiment, as shown in FIG. 4, the metal tube 8 includes a cylindrical portion 81 and a pair of flanges 82, 83 that protrude radially outward from both ends of the cylindrical portion 81. The flanges 82, 83 form both ends of the metal tube 8.

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

A normal pressure chamber 75 is formed between the outer circumferential surface of the metal tube 8 and the circumferential surface 73a of the storage chamber 73. This normal pressure chamber 75 is a space that allows the above-mentioned metal tube 8 to elastically deform radially outward. In this embodiment, the normal pressure chamber 75 is filled with hydraulic fluid. This hydraulic fluid leaks from the first flow path 71 through the gap between the first wall surface 73b and one end surface of the metal tube 8 and/or the gap between the second wall surface 73c and the other end surface of the metal tube 8.

The valve block 7 is formed with a drain passage 74 that extends from the normal pressure chamber 75 to the side. The opening of the drain passage 74 on the side of the valve block 7 is connected to a tank by piping (not shown). This configuration allows the hydraulic 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 can change).

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 is connected to 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 reduces 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 volume change 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 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 addition, in this embodiment, the storage chamber 73 includes a first wall surface 73b and a second wall surface 73c that face both end surfaces of the metal tube 8, so that the metal tube 8 can be sandwiched and held between the first wall surface 73b and the second wall surface 73c.

(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.

For example, the storage chamber 73 does not necessarily have to be located above the first flow path 71. For example, as in the first modified example shown in FIG. 5, the storage chamber 73 may be formed at a position away from the first flow path 71. In this case, a communication passage 78 is formed in the valve block 7 to connect the inside of the metal tube 8 to the first flow path 71. However, when the metal tube 8 constitutes part of the first flow path 71 as in the above embodiment, the valve block 7 can be made smaller than when the metal tube 8 is located at a location other than the first flow path 71.

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

Also, as in the second modified example shown in FIG. 6, the above-mentioned metal tube 8 may be arranged as the first metal tube 8 in the accommodation chamber 73, and a second metal tube 9 surrounding the first metal tube 8 may be arranged. 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 that protrude radially outward from both ends of the cylindrical portion 91. The flanges 92, 93 form both ends of the second metal tube 9.

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

The intermediate chamber 76, like the normal pressure chamber 75 in the previous embodiment, is filled with hydraulic 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.

The normal pressure chamber 77 is filled with hydraulic 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.

In the configuration shown in Figure 6, the metal tubes are arranged in a double layer, so the pressure difference acting on each metal tube is small. This makes it possible to use metal tubes that are more easily elastically deformed than when a single metal tube is used, and it is possible to reduce pressure pulsation over an even wider range.

In addition, metal tubes of various shapes other than the metal tube 8 having a cylindrical portion 81 and a pair of flanges 82, 83 can be used as the metal tube to be placed in the storage chamber 73.

For example, as in the third modified example shown in FIG. 7, a metal tube 8A of a constant thickness over its entire length may be placed in the storage 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 storage chamber 73 to keep the metal tube 8A in the center of the storage chamber 73.

Alternatively, as in the fourth modified example shown in FIG. 8, a metal tube 8B including a cylindrical portion 81 and a protrusion 84 that protrudes radially outward from the center of the cylindrical portion 81 and abuts against the peripheral surface 73a of the storage chamber 73 may be disposed within the storage chamber 73.

Furthermore, the storage 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 storage chamber 73 may be formed in the external block 7A so as to be positioned above the external flow path 71A. The metal tube 8 disposed in the storage chamber 73 constitutes part of the external flow path 71A.

In FIG. 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 so that the pipe is between the external block 7A and the valve block 7. In addition, in the storage chamber 73 formed in the external block 7A, a metal tube 8 may be arranged as the first metal tube 8, and a second metal tube 9 surrounding the first metal tube 8 may be arranged, as in FIG. 6.

In addition, in the configuration shown in FIG. 9, similar to FIG. 4, the normal pressure chamber 75 between the outer circumferential surface of the metal tube 8 and the circumferential surface 73a of the storage 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 surface of the first metal tube 8 and/or the gap between the second wall surface 73c and the other end surface of the first metal tube 8.

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 storage chambers 73 may be formed in the valve block 7, and two metal tubes 8 may be disposed in these storage chambers 73. One metal tube 8 may form a part of the first flow path 71, or the interior of one metal tube 8 may be connected to 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 be connected to the second flow path 72.

(summary)
According to one aspect of the present invention, there is provided a hydraulic rotary machine comprising: 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 within a housing 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.

In another aspect of the present invention, a hydraulic rotary machine includes a valve plate having a first port and a second port, 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 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 flow path communicating with the first port and a second flow path communicating with the second port, an external block attached to the valve block, the external flow path communicating with the first flow path, and a metal tube disposed in a chamber formed in the external block so as to be positioned above the external flow path, constituting a part of the external flow path and capable of elastic deformation radially outward.

A hydraulic rotary machine according to yet another 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, a cylinder block in which a plurality of pistons are inserted into a plurality of cylinder bores that slide against the valve plate, some of the cylinder bores communicate with the first port and some communicate with the second port as the cylinder block rotates, a valve block to which the valve plate is attached and in which a first flow path communicating with the first port and a second flow path communicating with the second port are formed, and a metal tube that is disposed in a chamber formed in the valve block at a position away from the first flow path, the interior of which communicates with the first flow path, and which is capable of elastic deformation radially outward.

According to the above configuration, the metal tube can be elastically deformed so as to expand or contract in diameter. Therefore, when 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 reduces the pulsation of the high pressure side pressure. Furthermore, the vibration frequency range in which the metal tube can vibrate due to volume change 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 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 placed in a place other than the first flow path.

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.

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

Between the outer peripheral surface of the metal tube and the peripheral surface of the housing chamber, an atmospheric pressure chamber is formed, which is the space that allows elastic deformation of the metal tube in the radially outward direction, and this atmospheric pressure chamber may be filled with working fluid leaked from the first flow path or the external flow path through the gap between the first wall surface and one end surface of the metal tube and/or the gap between the second wall surface and the other end surface of the metal tube. 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.

The metal tube is a first metal tube, and the hydraulic rotary machine further includes 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 the outer peripheral surface of the first metal tube and the inner peripheral surface of the second metal tube, which is the space that allows elastic deformation of the first metal tube radially outward, and this 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 hydraulic fluid leaking through a gap between the first wall surface and the other end face of the second metal tube, and a normal pressure chamber, which is a space that allows the second metal tube to elastically deform radially outward, is formed between the outer circumferential surface of the second metal tube and the circumferential surface of the storage chamber, and this normal pressure chamber may be filled with hydraulic 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 the pressure difference acting on one metal tube is reduced. Therefore, it is possible to use a metal tube that is more easily elastically deformed than when the metal tube is single-layered, and pressure pulsation can be reduced over a wider range.

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.

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 path, and the second flow path may be a suction path.

REFERENCE SIGNS LIST 1 hydraulic rotary machine 2 cylinder block 21 cylinder bore 3 piston 6 valve plate 61 first port 62 second port 7 valve block 71 first flow path 72 second flow path 73 accommodation chamber 73a peripheral surface 73b first wall surface 73c second wall surface 75 normal pressure chamber (space)
76 Intermediate Room (Space)
77 Normal pressure room (space)
7A External block 71A External flow passage 8 Metal pipe, first metal pipe 81 Cylindrical portion 82, 83 Flange 9 Second metal pipe 91 Cylindrical portion 92, 93 Flange

Claims (10)

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. 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. 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. The hydraulic rotating machine according to any one of claims 1 to 3, wherein a space is provided within the housing chamber to allow elastic deformation of the metal tube radially outward. The hydraulic rotating machine according to claim 4, wherein the housing chamber includes a peripheral surface surrounding the metal tube, a first wall surface facing one end surface of the metal tube, and a second wall surface facing the other end surface of the metal tube. The hydraulic rotating machine according to claim 5, wherein a normal pressure chamber, which is the space that allows the metal tube to elastically deform radially outward, is formed between the outer circumferential surface of the metal tube and the circumferential surface of the housing chamber, and the normal pressure chamber is filled with hydraulic fluid leaking through a gap between the first wall surface and one end surface of the metal tube and/or a gap between the second wall surface and the other end surface of the metal tube. 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. The hydraulic rotating 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. 4. The hydraulic rotary machine according to claim 1, wherein an atmospheric 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 atmospheric pressure chamber is in communication with a drain passage. 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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