hydraulic motor

Abstract

To provide a hydraulic motor that can reduce friction of movable parts while adopting water as hydraulic fluid.SOLUTION: A hydraulic motor adopts water as hydraulic fluid, and comprises a shaft and a rotor. The shaft comprises a first flow passage and a second flow passage. The rotor is rotatably supported by the shaft via a rotation bearing, and is rotated relatively with respect to the shaft by a fluid pressure of the hydraulic fluid. The rotation bearing is made of a porous material, and is fixed to the rotor. The hydraulic fluid is supplied to the rotation bearing by one of the first flow passage and the second flow passage, and the hydraulic fluid is discharged from the rotation bearing by the other. The rotor comprises a plurality of cylinders, and pistons housed in the cylinders, and is rotatably supported by an eccentric shaft. The rotor is housed in a case rotatably supported by a non-eccentric shaft. Bottom parts of the pistons comprise sliding bearings made of a porous material. The sliding bearings press pressure plates provided on an inner wall of the case.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to hydraulic motors, and more particularly to hydraulic motors that use water as the hydraulic fluid. [Background technology]

[0002] Hydraulic motors are known that are driven by the hydraulic pressure of a fluid. Generally, hydraulic motors use oil as the hydraulic fluid, but water motors use water as the hydraulic fluid. Water hydraulic motors can be driven using only tap water, for example, and are therefore suitable for use in places where cleanliness is required, such as environments where the use of oil is inappropriate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 61-185685 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-065522 Summary of the Invention [Problem to be solved by the invention]

[0004] In water hydraulic motors, lubricating oil cannot be used on moving parts such as the sliding parts of components such as pistons and the support parts of the rotating shaft. Because water has lower viscosity and lubricity than oil, it increases friction in these moving parts, which causes wear and tear and shortens the replacement cycle of parts.

[0005] In view of the above problems, an object of the present invention is to provide a hydraulic motor that uses water as a working fluid and is capable of reducing friction in moving parts. [Means for solving the problem]

[0006] The hydraulic motor according to the present invention comprises: A shaft (1) and a rotor (7) are provided. The shaft (1) has a first flow path (13) and a second flow path (14), The rotor (7) is rotatably supported on the shaft (1) via a rotary bearing (8), and rotates relative to the shaft (1) by hydraulic pressure of the hydraulic fluid. The rotary bearing (8) is made of a porous material and is fixed to the rotary body (7), a hydraulic fluid is supplied to the rotary bearing (8) through one of the first flow path (13) and the second flow path (14), and a hydraulic fluid is discharged from the rotary bearing (8) through the other of the first flow path (13) and the second flow path (14); The hydraulic fluid is water.

[0007] By using a hydraulic motor with such a configuration, it is possible to effectively reduce friction between the rotor and the shaft by using water as the hydraulic fluid.

[0008] Furthermore, the hydraulic motor according to the present invention comprises: The device comprises a first case (4), a second case (5) and a third case (6), The shaft (1) has an eccentric shaft (1B) and a non-eccentric shaft (1A, 1C), The third case (6) is connected to the first case (4) and the second case (5), The first case (4) and the second case (5) are rotatably supported on non-eccentric shafts (1A, 1C), The third case (6) accommodates the rotating body (7), The rotating body (7) is rotatably supported on the eccentric shaft (1B) of the shaft (1) via the rotary bearing (8), The rotating body (7) has a plurality of cylinders (9), Each of the cylinders (9) houses a piston (10); A pressure plate (20) facing the bottom (19) of the piston (10) is provided on the inner wall surface of the third case (6), The bottom (19) of the piston (10) presses against the pressure plate (20), The piston (10) has a supply and discharge hole (12), The rotary bearing (8) has an opening (23) that communicates with the supply and discharge hole (12), The hydraulic fluid flows into the cylinder (9) from one of the first flow path (13) and the second flow path (14) through the opening (23) and the supply / discharge hole (12), and is discharged from the cylinder (9) to the other of the first flow path (13) and the second flow path (14).

[0009] By using a hydraulic motor with such a configuration, friction caused by rotation can be reduced, and a high-performance radial hydraulic motor can be obtained.

[0010] Furthermore, the hydraulic motor according to the present invention comprises: the eccentric shaft (1B) has a first chamber (15) communicating with the first flow path (13) and a second chamber (16) communicating with the second flow path (14); The inner wall surface of the rotary bearing (8) faces the first chamber (15) and the second chamber (16), The hydraulic fluid is supplied to the rotary bearing (8) from one of the first chamber (15) and the second chamber (16), and the hydraulic fluid is discharged from the rotary bearing (8) to the other of the first chamber (15) and the second chamber (16).

[0011] Furthermore, the hydraulic motor according to the present invention comprises: The region of the inner wall surface of the rotary bearing (8) facing the first chamber (15) and the second chamber (16) is characterized by having a shape that can include the opening (23).

[0012] By using a hydraulic motor with such a configuration, it becomes easier to supply the working fluid to the rotary bearing.

[0013] Furthermore, the hydraulic motor according to the present invention comprises: The piston (10) has a sliding bearing (21) at the bottom (19), The sliding bearing (21) presses the pressure plate (20), The sliding bearing (21) is made of a porous material, The sliding bearing (21) is characterized in that the working fluid is supplied through a bottom outflow hole (22) provided in the bottom (19).

[0014] By using a hydraulic motor with such a configuration, it is possible to reduce friction caused by the sliding of the piston. [Effects of the Invention]

[0015] According to the present invention, it is possible to provide a hydraulic motor that can reduce friction of moving parts while using water as the working fluid. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1(A) is a schematic diagram showing a cross section of a hydraulic motor 100, and FIG. 1(B) is a schematic diagram showing a cross section of an eccentric portion. [Figure 2] 2A is a cross-sectional view of the vicinity of the bottom 19 of the piston 10, FIG. 2B is a cross-sectional view of the piston 10, and FIG. 2C is a plan view of the bottom 19 of the piston 10. FIG. [Figure 3] Figure 3(A) is a cross section near the eccentric shaft 1B, Figure 3(B) is a side view of the cylinder barrel 7, and Figure 3(C) is a perspective view showing a part of the inner wall surface of the ring bearing 8 as seen from the eccentric shaft 1B side. [Figure 4] FIG. 4 is a side view of the shaft 1. [Figure 5] FIG. 5 is a plan view showing an example of a valve plate for changing the direction of hydraulic fluid. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the following embodiments are not intended to limit the scope of the present invention. Furthermore, the same or similar components will be designated by the same reference numerals, and their description may be omitted. Furthermore, terms used in this specification that specify shapes, geometric conditions, and their degrees, such as "parallel," "orthogonal," "identical," "opposite," and "polygonal," as well as values ​​of lengths and angles, are not to be construed as being bound by strict meanings, but rather as including a range within which similar functions can be expected.

[0018] A hydraulic motor 100 according to the present invention will now be described. Figure 1 is an explanatory diagram showing the main internal configuration of a hydraulic motor 100 according to the present invention. Figure 1(A) is a schematic diagram showing a cross section of the hydraulic motor 100, and Figure 1(B) is a schematic diagram showing a cross section of an eccentric portion. Figure 1(B) is a cross section taken along line ZZ in Figure 1(A), and Figure 1(A) is a cross section taken along line WW in Figure 1(B). Figure 1 shows an example of a radial hydraulic motor. The hydraulic motor 100 uses water as a working fluid and generates a rotational force by utilizing hydraulic pressure (water pressure). Although the hydraulic fluid is assumed to be water, additives such as lubricants, disinfectants, and chemicals for adjusting the freezing point and boiling point may be added as needed.

[0019] The hydraulic motor 100 includes a shaft 1 that forms a rotation axis. The shaft 1 is divided into a non-eccentric region A (first non-eccentric region), an eccentric region B, and a non-eccentric region C (second non-eccentric region), and includes a non-eccentric shaft 1A (first non-eccentric shaft 1A), an eccentric shaft 1B, and a non-eccentric shaft 1C (second non-eccentric shaft 1C) corresponding to the non-eccentric region A and the non-eccentric region B. The eccentric shaft 1B is fixed between the non-eccentric shaft 1A and the non-eccentric shaft 1C, and is eccentric with respect to the non-eccentric shaft 1A and the non-eccentric shaft 1C. The central axes α of the non-eccentric shaft 1A and the non-eccentric shaft 1C are the same axis, whereas the central axis β of the eccentric shaft 1B does not coincide with the central axis α, and the central axes β and α are eccentric by a predetermined eccentricity e.

[0020] A rear case 4 (first case) and a front case 5 (second case) are provided on the outer periphery of the shaft 1. The rear case 4 is rotatably supported by a non-eccentric shaft 1A via a first bearing 2. The front case 5 is rotatably supported by a non-eccentric shaft 1C via a second bearing 3.

[0021] A main body 6 (third case) is provided between the rear case 4 and the front case 5. The main body 6 is located on the outer periphery of the eccentric shaft 1B within the eccentric region B, and houses a cylinder barrel . The rear case 4, the front case 5 and the main body 6 are connected and fixed by fasteners such as bolts, and the main body 6 can rotate together with the rear case 4 and the front case 5 around the central axis α of the shaft 1, particularly the non-eccentric shaft 1A and the non-eccentric shaft 1C.

[0022] The rear case 4 and the front case 5 are provided with seal members 41 and 51 for liquid-tightness.

[0023] A cylinder barrel 7 (rotating body) is provided inside the main body 6 on the outer periphery of the eccentric shaft 1B via a ring bearing 8, which is a cylindrical sliding bearing and a rotary bearing. The cylinder barrel 7 is rotatably supported by the eccentric shaft 1B. The ring bearing 8 is fixed to the cylinder barrel 7 and can rotate together with the cylinder barrel 7. As will be described later, the ring bearing 8 is made of a porous material.

[0024] The cylinder barrel 7 is provided with a plurality of cylinders 9 that open outward from the cylinder barrel 7. The plurality of cylinders 9 are arranged radially at equal angular intervals from one another. Each cylinder 9 houses a cylindrical piston 10 with a bottom. The piston 10 is slidably and liquid-tightly disposed within the cylinder 9 and is biased outward (towards the main body 6) by a spring 11. The piston 10 is cylindrical with only one end open, and is disposed so that the open end surface faces the eccentric shaft 1B. The reciprocating motion of the piston 10 installed within the cylinder 9 increases or decreases the volume of the working fluid contained within the cylinder 9.

[0025] 1, there are provided an odd number of cylinders 9, specifically five cylinders 9 and five pistons 10. The cylinder barrel 7 preferably has a polygonal prism shape with a substantially polygonal outer periphery, and since it is provided with a plurality of cylinders 9, the cylinder barrel 7 has a shape in which recesses are provided on the outer wall surface of the substantially polygonal prism. The inner peripheral surface of the main body 6 has a surface similar in shape to the polygonal outer peripheral surface of the cylinder barrel 7, and the bottom 19 of the piston 10 can come into contact with it. However, the shapes of the cylinder barrel 7 and the main body 6 are not limited to those described above.

[0026] The shaft 1, rear case 4, front case 5, main body 6, cylinder barrel 7 and piston 10 are made of a liquid-impermeable and highly corrosion-resistant metal, such as stainless steel, or a material such as resin, plastic or glass, or may be made of any combination of these.

[0027] Each cylinder 9 has a supply / discharge hole 12, and the ring bearing 8 has an opening 23 (communication port) at a position overlapping with the supply / discharge hole 12 of the cylinder 9. The supply / discharge hole 12 and the opening 23 allow the working fluid to be drawn into the cylinder 9 and discharged from the cylinder 9.

[0028] The shaft 1 has an intake passage 13 (first passage) and a discharge passage 14 (second passage) for flowing hydraulic fluid. In the example shown in FIG. 1 , the intake passage 13 and the discharge passage 14 extend from the non-eccentric shaft 1A to the eccentric shaft 1B. Hydraulic fluid supplied from the outside can flow through the intake passage 13 and the discharge passage 14. The hydraulic fluid can flow into (be supplied to) the cylinder 9 of the hydraulic motor 100 via the intake passage 13, and can flow out (be collected) from the cylinder 9 of the hydraulic motor 100 via the discharge passage 14. The hydraulic fluid discharged from the discharge passage 14 may then be discharged to the outside of the hydraulic motor 100 , or may be circulated and allowed to flow into the hydraulic motor 100 from the suction passage 13 . Alternatively, the intake passage 13 may extend from the non-eccentric shaft 1A to the eccentric shaft 1B, and the discharge passage 14 may extend from the eccentric shaft 1B to the non-eccentric shaft 1C.

[0029] The eccentric shaft 1B has therein a suction chamber 15 (first chamber) communicating with the suction passage 13 and a discharge chamber 16 (second chamber) communicating with the discharge passage 14. The suction chamber 15 and the discharge chamber 16 are configured as gaps in the eccentric shaft 1B. The intake flow path 13 has an intake port 130 (first port) at the boundary with the intake chamber 15, and the discharge flow path 14 has an exhaust port 140 (second port) at the boundary with the discharge chamber 16. The intake port 130 is configured as an opening for intake, and the exhaust port 140 is configured as an opening for exhaust (see Figures 1 and 4).

[0030] The supply and discharge holes 12 of each cylinder 9 and the openings 23 of the ring bearing 8 can be connected to the suction chamber 15 or the discharge chamber 16 by rotating the cylinder barrel 7. Depending on the rotation angle of the cylinder barrel 7, the cylinder 9 that is connected to the suction chamber 15 or the discharge chamber 16 changes sequentially. Furthermore, regardless of the rotation angle of the cylinder barrel 7, as shown in FIG. 1, the supply and discharge holes 12 of at least one cylinder 9 and the opening 23 of the ring bearing 8 communicate with the suction chamber 15, and the supply and discharge holes 12 of at least another cylinder 9 and the opening 23 of the ring bearing 8 communicate with the discharge chamber 16.

[0031] Of the multiple cylinders arranged radially in the cylinder barrel 7, working fluid flows into the suction-side cylinder 9 (suction-side cylinder 9a) through the suction passage 13, where the supply and discharge holes 12 and openings 23 communicate with the suction chamber 15. The pressure of the working fluid causes the suction-side piston 10 (suction-side piston 10a) in the suction-side cylinder 9a to move outward, increasing the volume of working fluid in the suction-side cylinder 9a. As a result, the suction-side piston 10a presses the main body 6 outward of the eccentric shaft 1B, increasing the distance between the suction-side cylinder 9a and the main body 6.

[0032] On the other hand, the discharge-side cylinder 9 (discharge-side cylinder 9b), which is a cylinder whose supply and discharge hole 12 and opening 23 communicate with the discharge chamber 16, is located on the side opposite the suction-side cylinder 9. When the distance between the suction-side cylinder 9a and the main body 6 increases, the distance between the discharge-side cylinder 9b and the main body 6 decreases. As a result, the piston 10 (discharge-side piston 10b) in the discharge-side cylinder 9b is pressed against the eccentric shaft 1B, and the volume of working fluid contained in the discharge-side cylinder 9b decreases. The working fluid inside the discharge-side cylinder 9b is discharged (exhausted) into the discharge chamber 16. The working fluid discharged into the discharge chamber 16 flows out into the discharge flow path 14.

[0033] The main body 6 is rotatably supported by the non-eccentric shaft 1A, and the cylinder barrel 7 is rotatably supported by the eccentric shaft 1B. Therefore, the reciprocating motion of the cylinder barrel 7 applies a rotational force to the eccentric shaft 1B around the central axis α of the non-eccentric shaft 1A. The cylinder barrel 7 rotates relative to the eccentric shaft 1B. When the non-eccentric shaft 1A is fixed, the main body 6 rotates, and when the main body 6 is fixed, the non-eccentric shaft 1A and the non-eccentric shaft 1C rotate. The hydraulic motor 100 can output rotational motion of the main body 6 or the non-eccentric shaft 1A and the non-eccentric shaft 1C.

[0034] When the main body 6 is fixed, the non-eccentric shafts 1A and 1C can be rotated continuously by alternately switching the flow direction of the hydraulic fluid on the supply side of the hydraulic fluid. In this case, the functions of the first flow path 13 and the second flow path 14 alternate to have a suction function or a discharge function. That is, the hydraulic fluid flows into the cylinder 9 from one of the first flow path 13 and the second flow path 14, and flows out from the cylinder 9 to the other of the first flow path 13 and the second flow path 14, and the flow direction of the hydraulic fluid in the first flow path 13 and the second flow path 14 is alternated. The functions of the first chamber 15 and the second chamber 16 are also alternated in the same way.

[0035] In order to alternate the flow direction of the hydraulic fluid, the opening and closing timing of the valve provided on the supply side of the hydraulic fluid may be adjusted in accordance with the rotation speed of the non-eccentric shafts 1A and 1C. For example, as shown in FIG. 5, a valve plate 26 having two arc-shaped slit portions 24, 25 may be provided on the opening sides of the intake flow path 13 and the discharge flow path 14, and the valve plate 26 may be fixed so that the flow of the working fluid is switched by rotating the non-eccentric shaft 1A.

[0036] A timing pin 17 (guide pin) fixed to the front case 5 and a timing ring 18 (guide ring) provided as a cylindrical recess in the cylinder barrel 7 guide the smooth movement of the cylinder barrel 7. The timing pin 17 traces a circular orbit while contacting the side wall of the timing ring 18.

[0037] 2A shows a cross-sectional view of the vicinity of the bottom 19 of the piston 10, FIG. 2B shows a cross-sectional view of the piston 10, and FIG. 2C shows a plan view of the bottom 19 of the piston 10. As shown in FIG. A pressure plate 20 is provided on the inner wall surface of the main body 6 so as to face the bottom 19 of each piston 10. The bottom 19 of each piston 10 presses against the pressure plate 20. Due to the movement of the cylinder barrel 7 guided by the timing pin 17 and the timing ring 18, the bottom 19 of the piston 10 reciprocates in a direction parallel to the surface of the pressure plate 20 (the X direction in FIG. 2A), and the main body 6 and the eccentric shaft 1B reciprocate relative to each other in the radial direction of the eccentric shaft 1B (the Y direction in FIG. 2A). By using a resin as the material for the pressure plate 20, for example, it is possible to reduce friction with the bottom 19 of the piston 10.

[0038] A circular groove 191 is provided in the bottom 19 of the piston 10, and a plate bearing 21, which is a sliding bearing that is a plate-shaped sliding bearing, is provided in the groove 191. The bottom 19 of the piston 10 is in indirect contact with the pressure plate 20 via a plate bearing 21 and moves back and forth along the surface of the pressure plate 20 while pressing against the pressure plate 20 . The plate bearing 21 contacts the pressure plate 20 of the main body 6 and has the function of reducing friction of the reciprocating motion of the piston 10 in the X direction. The plate bearing 21 is made of a porous material and is, for example, in the shape of a disk having a predetermined thickness. A bottom outflow hole 22 is provided in the bottom 19 of the piston 10, and water, which is the working fluid, is supplied to the plate bearing 21. 2(C), one bottom outflow hole 22 is disposed in the center of the bottom 19 as indicated by the dotted line, and the working fluid enters the plate bearing 21 from a location facing the bottom outflow hole 22 and then flows radially throughout the plate bearing 21. Multiple bottom outflow holes 22 may be provided to adjust the distribution of the working fluid supplied to the plate bearing 21. Strictly speaking, a film of working fluid is generated between the plate bearing 21 and the pressure plate 20, and therefore the plate bearing 21 and the pressure plate 20 come into contact with each other via a film of working fluid (water film).

[0039] As described above, the plate bearing 21 is made of a porous material, and its side wall surface is covered by the piston 10. The hydraulic fluid supplied from the bottom outflow holes 22 on the piston 10 side of the plate bearing 21 flows out from the surface of the plate bearing 21 that contacts the pressure plate 20, i.e., the surface of the piston 10 opposite the bottom outflow holes 22. A film of hydraulic fluid is generated between the plate bearing 21 on the bottom 19 of the piston 10 and the pressure plate 20, and the hydraulic pressure of the film of hydraulic fluid effectively reduces friction between the bottom 19 of the piston 10 and the pressure plate 20. As described above, by providing bottom outflow hole 22 in bottom 19 of piston 10, the hydraulic fluid itself can supply the liquid (water) for effectively operating plate bearing 21, so there is no need to provide a special circuit.

[0040] The rotation speed of the hydraulic motor 100 increases along with the hydraulic pressure of the hydraulic fluid. By using the hydraulic fluid as the fluid supplied to the plate bearing 21, the hydraulic pressure in the plate bearing 21 also increases in conjunction with this. As a result, the friction reduction effect can be automatically enhanced in conjunction with the increase in rotation speed. When the cylinder barrel 7 rotates, the centrifugal force further promotes the supply of the working fluid to the plate bearing 21.

[0041] Using low-viscosity water as the fluid supplied to the plate bearing 21 allows the working fluid to move within the porous material. Therefore, working fluid can be supplied from the surface of the plate bearing 21 facing the piston 10 and discharged from the surface on the opposite side, and the amount of working fluid discharged can be adjusted by adjusting the permeability of the porous material. In addition, water has high thermal conductivity, which suppresses temperature increases due to frictional heat. Furthermore, unlike oil, water is chemically stable and does not denature, so it does not clog narrow porous areas through which the liquid flows. Furthermore, water can be retained within the pores inside the porous material, and the response of the liquid within the porous material can be improved.

[0042] As the porous material, for example, porous resin, porous carbon, porous ceramics, and porous metal can be used. The amount of hydraulic fluid supplied between the plate bearing 21 and the pressure plate 20 can be adjusted by the permeability of the porous material. In addition, the hydraulic fluid can be held in the pores inside the porous material that makes up the plate bearing 21.

[0043] Figure 3(A) shows a cross section near the eccentric shaft 1B, Figure 3(B) is a side view of the cylinder barrel 7, and Figure 3(c) is a perspective view showing a part of the inner wall surface of the ring bearing 8 as seen from the eccentric shaft 1B side. FIG. 3(B) shows a side view of the cylinder barrel 7 in a state where the supply / discharge hole 12 of the cylinder 9 and the suction port 130 of the suction passage 13 are aligned. FIG. 3B shows an example in which the opening 23 is positioned opposite the suction port 130. The arrows in FIG. 3(A) and FIG. 3(C) indicate the flow of the hydraulic fluid. FIG. 4 is a side view of the shaft 1.

[0044] The hydraulic fluid is pumped from the outside into the intake passage 13 and flows into the intake chamber 15 via the intake port 130 (see FIGS. 3 and 4). As shown in FIG. 3(A), the working fluid in the suction chamber 15 flows into the suction side cylinder 9a) through the opening 23 of the ring bearing 8 and the supply / discharge hole 12.

[0045] A porous material can be used as the material for forming the ring bearing 8. Examples of the porous material that can be used include porous resin, porous carbon, porous ceramics, and porous metal. The working fluid flows into the ring bearing 8 other than the opening 23 from the suction chamber 15 shown by the dotted line in FIG. 3(B). The inner wall surface of the ring bearing 8 contacts the outer wall surface of the eccentric shaft 1B in an area other than the suction chamber 15 and the discharge chamber 16. Strictly speaking, a film of working fluid is formed between the inner wall surface of the ring bearing 8 and the outer wall surface of the eccentric shaft 1B, but this means that the two come into contact via the film of working fluid.

[0046] The inner wall surface of the ring bearing 8 faces the suction chamber 15 and the discharge chamber 16 and covers the suction chamber 15 and the discharge chamber 16 . 3(B), the area of ​​the inner wall surface of ring bearing 8 that faces suction chamber 15 has a shape that includes opening 23. Similarly, when opening 23 faces discharge port 140, the area of ​​the inner wall surface of ring bearing 8 that faces discharge chamber 16 has a shape that includes opening 23. Therefore, the working fluid can flow into the ring bearing 8 through the inner wall surface of the ring bearing 8 from the region where the inner wall surface of the ring bearing 8 faces the suction chamber 15. Also, the working fluid can flow out of the ring bearing 8 through the inner wall surface of the ring bearing 8 from the region where the inner wall surface of the ring bearing 8 faces the discharge chamber 16. 3(A) and 3(C), the working fluid that flows from the suction chamber 15 into the porous ring bearing 8 spreads throughout the entire interior of the ring bearing 8. In addition, the working fluid can be retained within the pores of the porous material.

[0047] As shown in FIG. 3(A), the working fluid that flows toward the discharge side cylinder 9b in the ring bearing 8 flows into the discharge chamber 16 and then flows into the discharge flow path 14 via the discharge port 140 (see FIGS. 3 and 4). In this way, the working fluid is supplied to the ring bearing 8 via the intake passage 13 and is recovered via the discharge passage 14.

[0048] When the shaft 1 rotates, the functions of the first flow passage 13 and the second flow passage 14 alternate, so that the hydraulic fluid flows from one of the first chamber 15 and the second chamber 16 into the ring bearing 8 and flows from the ring bearing 8 to the other of the first chamber 15 and the second chamber 16.

[0049] Furthermore, the relative rotational motion between the cylinder barrel 7 and the eccentric shaft 1B further promotes the supply of working fluid to the ring bearing 8 by centrifugal force, and also promotes the movement of working fluid in the circumferential direction. Because the ring bearing 8 is fixed in contact with the cylinder barrel 7, when working fluid fills the ring bearing 8, it is supplied between the inner surface (inner wall surface) of the ring bearing 8 and the outer surface (outer wall surface) of the eccentric shaft 1B. As a result, a film of working fluid is generated between the ring bearing 8 and the eccentric shaft 1B, reducing friction between the ring bearing 8 and the eccentric shaft 1B. The pressure of the film of working fluid that is generated depends on the pressure of the working fluid and the permeability of the porous material that makes up the ring bearing 8.

[0050] Since the hydraulic fluid that drives the piston 10 is supplied to the plate bearing 21 and the ring bearing 8, there is no need to provide a special supply water passage separately. As with the plate bearing 21, the rotational speed increases as the hydraulic pressure of the hydraulic fluid increases, and the hydraulic pressure supplied to the ring bearing 8 also increases accordingly, enhancing the friction reduction effect. As a result, there is no waste in the supply of hydraulic fluid to the plate bearing 21 and the ring bearing 8, and friction and frictional heat can be reduced efficiently.

[0051] Unlike the plate bearing 21 of the piston 10, the working fluid is supplied from the inner surface of the ring bearing 8 facing the suction chamber 15 of the eccentric shaft 1B, spreads inside the ring bearing 8, and is discharged from the entire inner surface of the ring bearing 8 to the eccentric shaft 1B side. Furthermore, because the ring bearing 8 rotates, the pressure of the flowing hydraulic fluid increases in areas where the gap between the ring bearing 8 and the eccentric shaft 1B is narrow, and pressure is applied in the direction that widens the gap between the ring bearing 8 and the eccentric shaft 1B. As a result, the gap between the ring bearing 8 and the eccentric shaft 1B is kept uniform, further reducing friction between the ring bearing 8 and the eccentric shaft 1B.

[0052] The porous material may be a material that is homogeneous in the thickness direction, or materials with different permeabilities to the working fluid may be laminated in the thickness direction. For example, it is possible to combine and laminate a porous material with low permeability (e.g., 15% permeability) and an average pore diameter of 0.5 μm to 1 μm (0.5 μm≦average diameter≦1 μm) and a porous material with high permeability (e.g., 35% permeability) and an average pore diameter of 5 μm to 10 μm (5 μm≦average diameter≦10 μm).

[0053] For example, the porous material of the plate bearing 21 may be configured so that a porous material with a relatively high permeability to the working fluid is arranged on the side in contact with the piston 10, and a porous material with a relatively low permeability to the working fluid is arranged on the side in contact with the opposing pressure plate 20. The working fluid supplied from the bottom outlet holes 22 of the piston 10 moves parallel to the bottom 19 of the piston 10 through the porous material with high permeability and low movement resistance, and then moves in the film thickness direction of the plate bearing 21 through the porous material with low permeability. As a result, the uniformity of the working fluid supplied to the interface between the pressure plate 20 and the plate bearing 21 can be improved.

[0054] As an example of the porous material configuration of the ring bearing 8, a porous material with a relatively low permeability to the working fluid may be arranged on the inner diameter side (the eccentric shaft 1B side) and a porous material with a relatively high permeability to the working fluid may be arranged on the outer diameter side (the cylinder barrel 7 side). By using a porous material with a high permeability on the outer diameter side, working fluid can be supplied to the entire ring bearing 8, and the porous material with a low permeability on the inner diameter side can supply the necessary amount of fluid to the eccentric shaft 1B side. It is possible to adjust the hydraulic pressure distribution of the working fluid in the circumferential direction of the ring bearing 8. Furthermore, by ensuring the amount of working fluid retained inside the ring bearing 8, the responsiveness of the supply of working fluid from the ring bearing 8 to the eccentric shaft 1B side is high, especially when starting rotation or changing the rotation speed.

[0055] In order to prevent the working fluid from leaking out from the upper and lower end faces S of the ring bearing 8, the surfaces of the end faces S may be liquid-tightly sealed with resin or the like.

[0056] As described above, the hydraulic fluid, which is the power source that rotates the cylinder barrel 7 around the eccentric shaft 1B, is supplied to the ring bearing 8 made of a porous material fixed to the cylinder barrel 7, thereby reducing friction between the eccentric shaft 1B and the cylinder barrel 7. Therefore, the supply of hydraulic fluid to the ring bearing 8 increases along with the relative rotation speed between the eccentric shaft 1B and the cylinder barrel 7, thereby effectively reducing friction.

[0057] Although the above embodiment has been described with reference to a radial piston motor, the ring bearing 8 can also be applied to an axial piston motor. For example, in a swash plate type piston motor, a supply / discharge hole is provided at the bottom of the piston to allow hydraulic fluid to flow into the piston shoe side, and a porous plate bearing is provided at the bottom of the piston shoe, supplying some of the hydraulic fluid to the plate bearing to reduce friction between the piston shoe and the swash plate. The rotation speed of the axial piston motor and the hydraulic pressure supplied to the plate bearing can be linked, effectively reducing friction and frictional heat. [Industrial Applicability]

[0058] According to the present invention, by using a porous material as the bearings that support the sliding and / or rotating parts of a hydraulic motor and by using low-viscosity water as the working fluid, it is possible to supply working fluid to the bearings of the sliding and / or rotating parts, thereby effectively reducing friction, thereby reducing energy loss due to friction and achieving a highly efficient hydraulic motor. [Explanation of symbols]

[0059] 100 hydraulic motor 1 shaft 1A Non-eccentric shaft (first non-eccentric shaft) 1B Eccentric shaft 1C Non-eccentric shaft (second non-eccentric shaft) 2 First bearing 3 Second bearing 4 Rear case (first case) 41 Sealing material 5 Front case (second case) 51 Sealing material 6 Main body (third case) 7 Cylinder barrel (rotating body) 8 Rotary bearings (ring bearings) 9 cylinders 9a Intake side cylinder 9b Discharge side cylinder 10 pistons 10a Intake side piston 10b Discharge side piston 11 Spring 12 Supply / discharge hole 13 Intake flow path (first flow path) 130 Intake port (first port) 14 Discharge flow path (second flow path) 140 Discharge port (second port) 15. Inhalation chamber (first chamber) 16 Discharge chamber (second chamber) 17 Timing pin (guide pin) 18 Timing ring (guide ring) 19 Bottom 191 Groove 20 Pressure Plate 21 Sliding bearing (plate bearing) 22 Bottom outflow hole 23 Opening (communication port) 24, 25 Slit section 26 Valve plate A Non-eccentric area (first non-eccentric area) B Eccentric region C. Non-eccentric area (second non-eccentric area) α center axis β central axis

Claims

1. A shaft and a rotor are provided, the shaft has a first flow passage and a second flow passage; the rotating body is rotatably supported on the shaft via a rotary bearing, an inner wall surface of the rotary bearing contacts an outer wall surface of the shaft; The rotary bearing and the rotary body have the same length along the longitudinal direction of the shaft, The hydraulic fluid rotates the rotor relative to the shaft. The rotary bearing is made of a porous material and is fixed to the rotating body, the hydraulic fluid is supplied from an inner wall surface of the rotary bearing through one of the first flow path and the second flow path, and the hydraulic fluid is discharged from the inner wall surface of the rotary bearing through the other of the first flow path and the second flow path, A hydraulic motor characterized in that the working fluid is water.

2. a first case, a second case, and a third case; The shaft includes an eccentric shaft and a non-eccentric shaft; the third case is connected to the first case and the second case; the first case and the second case are rotatably supported on the non-eccentric shaft; the third case accommodates the rotating body, the rotating body is rotatably supported by the eccentric shaft of the shaft via the rotary bearing, the rotating body has a plurality of cylinders, Each of the cylinders houses a piston; a pressure plate facing the bottom of the piston is provided on an inner wall surface of the third case; The bottom of the piston presses against the pressure plate, The piston has a supply and discharge hole, the rotary bearing has an opening communicating with the supply and discharge hole, 2. The hydraulic motor according to claim 1, wherein the hydraulic fluid flows into the cylinder from one of the first flow path and the second flow path via the opening and the supply / discharge hole, and is discharged from the cylinder to the other of the first flow path and the second flow path.

3. the eccentric shaft has a first chamber in communication with the first flow path and a second chamber in communication with the second flow path; an inner wall surface of the rotary bearing faces the first chamber and the second chamber; 3. The hydraulic motor according to claim 2, wherein the hydraulic fluid is supplied to the rotary bearing from one of the first chamber and the second chamber, and the hydraulic fluid is discharged from the rotary bearing to the other of the first chamber and the second chamber.

4. 4. The hydraulic motor according to claim 1, wherein an end face of the rotary bearing is sealed liquid-tightly.

5. A shaft and a rotor, The device includes a first case, a second case, and a third case, the rotating body is rotatably supported on the shaft via a rotary bearing, the shaft has a first flow path and a second flow path, and has an eccentric shaft and a non-eccentric shaft; the third case is connected to the first case and the second case; the first case and the second case are rotatably supported on the non-eccentric shaft; the third case accommodates the rotating body, the rotating body is rotatably supported by the eccentric shaft of the shaft via the rotary bearing, and rotates relative to the shaft by hydraulic pressure of the hydraulic fluid; the rotating body has a plurality of cylinders, Each of the cylinders houses a piston; a pressure plate facing the bottom of the piston is provided on an inner wall surface of the third case; The bottom of the piston presses against the pressure plate, The piston has a supply and discharge hole, the rotary bearing has an opening communicating with the supply and discharge hole, the hydraulic fluid flows into the cylinder from one of the first flow path and the second flow path through the opening and the supply / discharge hole, and is discharged from the cylinder to the other of the first flow path and the second flow path; The piston has a sliding bearing at the bottom, the sliding bearing presses the pressure plate; the sliding bearing is made of a porous material, The sliding bearing is supplied with the hydraulic fluid through a bottom outlet hole provided in the bottom, A hydraulic motor characterized in that the working fluid is water.

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