Fluid-operated machinery

Abstract

To enable fluid to be properly supplied to a sliding surface via a flow passage portion.SOLUTION: A fluid-operated machinery comprises: a cylinder 11 having a housing portion 11a housing fluid; a piston 21 reciprocating in the cylinder; and a crankshaft 26 which has a sliding surface 29 sliding with respect to the piston 21, and which performs rotational motions in conjunction with the reciprocation of the piston 21. The piston 21 has: a communication path 54 which axially penetrates through the piston 21, and in which the fluid flows; and a recess 56 communicating with the communication path 54 at the housing portion 11a side, and having an opening area which is larger than that of the communication path 54. The fluid-operated machinery further comprises a filter member 60 which is provided in the recess 56.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a fluid-working machine that performs energy conversion between a fluid and a machine. [Background technology]

[0002] The following Patent Document 1 discloses a radial pump motor that supplies a fluid (oil) to a sliding surface via a flow passage that penetrates a piston that reciprocates in a cylinder arranged around a rotating shaft. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-99350 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, the diameter of the flow path portion that communicates with the container portion that contains the fluid is small so as to prevent the amount of fluid supplied to the sliding surface from becoming too large. Therefore, if foreign matter is mixed into the container portion, the foreign matter may block the flow path portion, and the fluid may not be properly supplied to the sliding surface.

[0005] The present invention has been made in consideration of these points, and has an object to make it possible to appropriately supply a fluid to a sliding surface through a flow path portion. [Means for solving the problem]

[0006] In one aspect of the present invention, there is provided a fluid-working machine comprising: a cylinder having a storage portion for storing a fluid; a piston which reciprocates within the cylinder; and a rotating shaft which has a sliding surface which slides against the piston and which rotates in conjunction with the reciprocating motion of the piston, the piston penetrating the piston in the axial direction and having a flow path portion through which the fluid flows, and a recess which is connected to the storage portion side of the flow path portion and has a larger opening area than the flow path portion, and further comprising a filter member provided within the recess.

[0007] The length of the filter member in the axial direction may be greater than half the length of the flow path portion.

[0008] The width of the filter member may be greater than twice the diameter of the flow path portion.

[0009] Furthermore, when the rotating shaft rotates, the fluid in the accommodation portion may pass through the filter member and the flow passage portion and flow onto a sliding surface of the rotating shaft where the piston slides.

[0010] The filter member may be formed in a cylindrical shape and may be fitted into the recess.

[0011] In addition, the piston may have a shaft portion that reciprocates within the cylinder and an opposing portion that is connected to the shaft portion and faces the sliding surface of the rotating shaft, the flow path portion may penetrate the opposing portion along the axial direction, and the recess may penetrate the shaft portion along the axial direction and be connected to the flow path portion.

[0012] The length of the filter member in the axial direction may be greater than the length of the flow passage portion.

[0013] The cylinder and the piston may be arranged in a plurality of parts at predetermined intervals in the circumferential direction of the rotation shaft. Effect of the Invention

[0014] According to the present invention, an effect is achieved in that the fluid can be appropriately supplied to the sliding surface via the flow path portion. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a schematic diagram showing a schematic configuration of a fluid working machine 1 according to one embodiment. [Diagram 2] 2 is a schematic diagram showing the internal configuration of a cylinder 11 and a piston 21. FIG. [Diagram 3] FIG. 13 is a schematic diagram for explaining a comparative example. [Figure 4] 1 is a schematic diagram showing a state in which foreign matter adheres to a filter member 60 in this embodiment. [Diagram 5] FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] <Configuration of fluid working machines> A configuration of a fluid working machine according to one embodiment will be described. In the following description, a hydraulic pump motor will be taken as an example of a fluid working machine, but the fluid working machine is not limited to a hydraulic pump motor. A fluid working machine is also called a fluid machine, and is generally a device that converts energy between a fluid and a machine. As the fluid, liquids such as water or oil, or gases such as air or gas are used, and applications such as low-speed rotation and high-speed rotation vary depending on the properties of the fluid, such as density and viscosity.

[0017] 1 is a schematic diagram showing a schematic configuration of a fluid working machine 1 according to one embodiment. The fluid working machine 1 is mounted on a vehicle such as a truck. The fluid working machine 1 transmits generated power to drive wheels of the vehicle, for example.

[0018] The fluid working machine 1 has cylinders 11, 12, 13, 14, a first supply passage 16, a second supply passage 18, pistons 21, 22, 23, 24, a crankshaft 26, and valve units 31, 32, 33, 34. Although four cylinders 11-14 and four pistons 21-24 are provided, the present invention is not limited to this, and the numbers of cylinders and pistons may be three or five or more.

[0019] The cylinders 11 to 14 are arranged in the circumferential direction of the crankshaft 26. The four cylinders 11 to 14 are arranged at predetermined intervals (specifically, at 90 degree intervals) along the circumferential direction.

[0020] The first supply path 16 is a flow path that connects a first chamber 17 that contains a high-pressure fluid to the cylinders 11-14. The first supply path 16 branches so as to supply fluid to the four cylinders 11-14. The second supply path 18 is a flow path that connects a second chamber 19 that contains a low-pressure fluid to the cylinders 11-14. The second supply path 18 also branches so as to supply fluid to the four cylinders 11-14.

[0021] The pistons 21-24 are arranged in the circumferential direction of the crankshaft 26, and reciprocate inside the cylinders 11-14. The pistons 21-24 reciprocate due to the pressure of the fluid supplied to the cylinders 11-14. For example, the reciprocating motion of the pistons 21-24 rotates the crankshaft 26 in contact with the pistons 21-24.

[0022] Crankshaft 26 is a rotating shaft that rotates in conjunction with the reciprocating motion of pistons 21-24. Crankshaft 26 has shaft portion 27 and cam portion 28. Shaft portion 27 is the shaft portion of crankshaft 26. The center of rotation of shaft portion 27 is the position where the central axes of four pistons 21-24 intersect. Cam portion 28 is provided eccentrically on the outer periphery of shaft portion 27. Cam portion 28 has sliding surface 29 that slides against pistons 21-24. Sliding surface 29 is the outer circumferential surface of cam portion 28. With this configuration, the reciprocating motion of pistons 21-24 is converted into the rotational motion of shaft portion 27 via cam portion 28.

[0023] The valve units 31-34 regulate the flow of high-pressure fluid in the first chamber 17 and low-pressure fluid in the second chamber 19 to the cylinders 11-14. Each of the valve units 31-34 regulates the flow of fluid to the corresponding cylinders 11-14. For example, the valve unit 31 regulates the flow of fluid to the cylinder 11.

[0024] In the above description, the pistons 21-24 reciprocate due to the pressure of the fluid supplied to the cylinders 11-14, thereby rotating the crankshaft 26. However, this is not limited to the above, and for example, the pistons 21-24 may reciprocate as the crankshaft 26 connected to the vehicle transmission rotates, thereby supplying the fluid in the cylinders 11-14 to the first chamber 17 or the second chamber 19.

[0025] <Detailed structure of cylinder and piston> The cylinders 11 to 14 have the same configuration, and the pistons 21 to 24 have the same configuration. In the following, the detailed configurations of the cylinder 11 and the piston 21 will be described by taking the cylinder 11 and the piston 21 as an example.

[0026] FIG. 2 is a schematic diagram showing the internal configuration of the cylinder 11 and the piston 21. As shown in FIG. The cylinder 11 has a storage portion 11a that stores a fluid. As described above, the fluid is supplied to the storage portion 11a via the valve unit 31 (FIG. 1). The fluid in the storage portion 11a exerts pressure on the upper surface of the piston 21 (specifically, the upper surface 51a of the shaft portion 50 of the piston 21). The fluid stored in the storage portion 11a is oil in this embodiment.

[0027] The piston 21 reciprocates within the cylinder 11. For example, the piston 21 receives pressure from the fluid in the accommodation portion 11a and moves downward in FIG. 2. The piston 21 has a shaft portion 50, an opposing portion 52, a communication passage 54, and a recess 56.

[0028] The shaft portion 50 is formed in a cylindrical shape, and is a part that reciprocates within the cylinder 11. An upper surface 51a of the shaft portion 50 contacts the accommodation portion 11a of the cylinder 11. The upper surface 51a receives pressure from the fluid in the accommodation portion 11a. When the upper surface 51a receives pressure, the piston 21 moves downward in FIG. 2. A gap is formed between an outer peripheral surface 51b of the shaft portion 50 and an inner wall surface 11b of the cylinder 11.

[0029] The facing portion 52 is a portion facing the sliding surface 29 of the cam portion 28 of the crankshaft 26. The facing portion 52 is a lower portion of the piston 21, and is connected to the lower end of the shaft portion 50. The facing surface 53, which is the lower surface of the facing portion 52, is curved so as to be parallel to the sliding surface 29 of the cam portion 28. The fluid in the storage portion 11a flows between the facing surface 53 and the sliding surface 29. The facing portion 52 receives pressure from the fluid between the facing surface 53 and the sliding surface 29.

[0030] The communication passage 54 is a flow path provided in the piston 21, and communicates with the accommodation portion 11a of the cylinder 11. Therefore, the fluid in the accommodation portion 11a flows to the sliding surface 29 through the communication passage 54, as shown by the dashed arrow in Fig. 2. The communication passage 54 is provided so as to penetrate the piston 21 along the axial direction. Specifically, the communication passage 54 is provided so as to penetrate one axial end portion of the shaft portion 50 and the center of the opposing portion 52.

[0031] The recess 56 is a portion recessed from the upper surface 51a of the shaft portion 50, and is provided at the other axial end portion of the shaft portion 50. The recess 56 is provided at the center of the shaft portion 50. The recess 56 communicates with the communication passage 54 on the storage portion 11a side. The opening area of ​​the recess 56 is larger than the opening area of ​​the communication passage 54.

[0032] A filter member 60 is provided in the recess 56. A lower surface 61 of the filter member 60 in the recess 56 contacts a bottom surface 57 of the recess 56 and covers the communicating passage 54. By providing the filter member 60 in the recess 56, it is possible to prevent foreign matter that has entered the storage portion 11a from blocking the communicating passage 54.

[0033] The filter member 60 is a mesh (porous) member, and is made of a foam such as a sponge. The mesh size (pore size) of the filter member 60 is set to allow fluid to pass through while preventing foreign matter from passing through. Therefore, even if the filter member 60 is provided in the recess 56, the fluid that has passed through the filter member 60 can reach the sliding surface 29. That is, when the crankshaft 26 rotates, the fluid in the housing portion 11a passes through the filter member 60 and the communication passage 54 and flows to the sliding surface 29 of the crankshaft 26 (specifically, between the opposing surface 53 and the sliding surface 29).

[0034] The filter member 60 is formed in a cylindrical shape and is fitted into the recess 56. For example, the filter member 60 may be press-fitted into the recess 56. In the case of the above configuration, it is possible to prevent the filter member 60 from coming off the recess 56 while the piston 21 is performing a reciprocating motion.

[0035] The advantages of providing the filter member 60 will be described below in comparison with a comparative example shown in FIG. FIG. 3 is a schematic diagram for explaining a comparative example. In the piston 121 according to the comparative example, the recess 56 and the filter member 60 described above are not provided. In addition, the communication passage 154 of the piston 121 penetrates the shaft portion 150 and the opposing portion 152 of the piston 121. In the comparative example, the foreign matter 70 blocks the communication passage 154 at the upper surface 151a of the shaft portion 150. Here, the size of the foreign matter 70 is larger than the diameter of the communication passage 154, so the foreign matter 70 cannot enter the communication passage 154 and blocks the communication passage 154. The foreign matter 70 is, for example, a burr (protrusion) generated during metal processing of the piston 121 or the cylinder 11 that is removed during the reciprocating motion of the piston 121. However, the present invention is not limited to this, and the foreign matter 70 may be transported to the storage portion 11a together with the fluid from the first chamber 17 or the second chamber 19.

[0036] When the foreign object 70 blocks the communication passage 154 at the upper surface 151a, the foreign object 70 becomes an obstacle, making it difficult for the fluid to flow through the communication passage 154. This reduces the amount of fluid flowing to the sliding surface 29, which may cause the opposing portion 152 to come into contact with the sliding surface 29. When the opposing portion 152 comes into contact with the sliding surface 29, significant wear occurs in the opposing portion 152 and the sliding surface 29, and seizure may occur in the opposing portion 152 and the sliding surface 29. Furthermore, when the foreign object 70 enters the gap between the inner wall surface 11b of the cylinder 11 and the outer circumferential surface 151b of the piston 121, the cylinder 11 becomes more susceptible to wear.

[0037] 4 is a schematic diagram showing a state in which foreign matter is attached to the filter member 60 in this embodiment. Here, foreign matter 70 is attached to the upper surface 62 of the filter member 60. As described above, since the filter member 60 is a mesh-like member, the foreign matter 70 is likely to adhere to and remain on the upper surface 62 of the filter member 60 even when the piston 21 reciprocates. Here, since the size of the foreign matter 70 is larger than the holes of the filter member 60, the foreign matter 70 does not enter the filter member 60 but adheres to and remains on the upper surface 62. As a result, the foreign matter 70 can be prevented from blocking the communication passage 54, while the fluid passes through the filter member 60 and flows to the sliding surface 29.

[0038] If the size of the foreign matter 70 is smaller than the holes in the filter member 60, the foreign matter 70 may enter the filter member 60, but since the filter member 60 is thick, the foreign matter 70 is likely to remain inside the filter member 60. This makes it possible to prevent the foreign matter 70 from reaching the communication passage 54. Furthermore, the foreign matter 70 adheres to and remains on the filter member 60, thereby preventing the foreign matter 70 from entering the gap between the inner wall surface 11b of the cylinder 11 and the outer circumferential surface 151b of the piston 121. As a result, wear of the cylinder 11 caused by the foreign matter 70 can be suppressed.

[0039] The cylindrical filter member 60 has, for example, the following dimensions. 4, the width of the filter member 60 is larger than the diameter of the communication passage 54. Specifically, the width of the filter member 60 is more than twice the diameter of the communication passage 54. By providing a filter member 60 with a large width, foreign matter 70 in the storage section 11a is more likely to adhere to and remain on the filter member 60. This makes it possible to prevent the foreign matter 70 from moving into the gap between the inner wall surface 11b of the cylinder 11 and the outer circumferential surface 151b of the piston 121.

[0040] 4, the axial length of the filter member 60 (in other words, the thickness) is greater than half the length of the communicating passage 54. Specifically, the thickness of the filter member 60 is greater than the length of the communicating passage 54. In this case, even if a small foreign object 70 enters the filter member 60, the foreign object 70 is more likely to be captured within the thicker filter member 60. However, without being limited to the above, the axial length of the filter member 60 may be less than half the length of the communicating passage 54.

[0041] When the filter member 60 is provided in the recess 56, it is possible to adjust the flow rate of the fluid flowing to the sliding surface 29. Specifically, the flow rate of the fluid passing through the filter member 60 can be adjusted by the mesh size and thickness of the filter member 60, and therefore the flow rate of the fluid flowing to the sliding surface 29 can be adjusted. The mesh size and thickness of the filter member 60 are set to optimal values ​​based on experiments, simulations, etc.

[0042] (Modification) Fig. 5 is a schematic diagram showing a modified example. In this modified example, the configurations of the recess 86 and the filter member 90 are different from those of the recess 56 and the filter member 60 shown in Fig. 2, but the other configurations are the same as those shown in Fig. 2. Therefore, the configurations of the recess 86 and the filter member 90 will be described below.

[0043] The recess 86 is provided so as to penetrate the entire shaft portion 50. The communication passage 84 is a flow path portion that penetrates the opposing portion 52 along the axial direction. Therefore, the recess 86 penetrates the shaft portion 50 along the axial direction and communicates with the communication passage 84. The depth of the recess 86 is longer than the length of the communication passage 84.

[0044] The filter member 90 is provided in the recess 86 so as to fill the entire recess 86. Specifically, the cylindrical filter member 90 is fitted into the recess 86. The axial length (i.e., thickness) of the filter member 90 is greater than the length of the communicating passage 84. The thickness of the filter member 90 is greater than the thickness of the filter member 60 shown in FIG. 2.

[0045] Even in this modification, by providing the recess 86 and the filter member 90 in the piston 21, the foreign matter 70 adheres to and remains on the filter member 90, so that the foreign matter 70 can be prevented from blocking the communication passage 84.

[0046] <Effects of this embodiment> The piston 21 of the fluid working machine 1 of the embodiment described above has a recess 56 that penetrates the piston 21 in the axial direction, communicates with a communication passage 54 through which the fluid flows, and communicates with the accommodation section 11a side of the communication passage 54, and has an opening area larger than that of the communication passage 54. A filter member 60 is provided within the recess 56. In the above configuration, the foreign matter 70 in the storage portion 11a is likely to adhere to and remain on the filter member 60. This prevents the foreign matter 70 from clogging the communication passage 54, allowing the fluid to pass through the filter member 60 and flow appropriately to the sliding surface 29. As a result, it is possible to prevent the opposing portion 52 of the piston 21 and the sliding surface 29 from coming into contact with each other and wearing them. Furthermore, by the foreign matter 70 adhering to and remaining on the filter member 60, it is possible to prevent the foreign matter 70 from entering the gap between the piston 21 and the cylinder 11, thereby preventing wear on the cylinder 11.

[0047] Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments, and various modifications and changes are possible within the scope of the gist of the present invention. For example, all or part of the device can be configured by distributing or integrating functionally or physically in any unit. In addition, new embodiments resulting from any combination of multiple embodiments are also included in the embodiments of the present invention. The effect of the new embodiment resulting from the combination combines the effect of the original embodiment. [Explanation of symbols]

[0048] 1 Fluid-operated machines 11~14 cylinders 11a Storage section 21~24 Piston 26 Crankshaft 29 Sliding surface 50 Shaft 52 Opposing part 54 Communication path 56 Recess 60 Filter material 86 Recess 90 Filter material

Claims

1. A cylinder having a container for containing a fluid; A piston that reciprocates within the cylinder; a rotating shaft having a sliding surface that slides against the piston and that rotates in conjunction with the reciprocating motion of the piston, The piston is a flow passage portion penetrating the piston in an axial direction and through which the fluid flows; a recess that is in communication with the flow path portion on the side of the accommodation portion and has an opening area larger than that of the flow path portion, The fluid working machine further comprises a filter member disposed within the recess.

2. The axial length of the filter member is greater than half the length of the flow path portion.

2. A fluid-working machine according to claim 1.

3. The width of the filter member is greater than twice the diameter of the flow path portion.

2. A fluid-working machine according to claim 1.

4. When the rotating shaft rotates, the fluid in the accommodation portion passes through the filter member and the flow passage portion and flows onto a sliding surface of the rotating shaft with the piston.

2. A fluid-working machine according to claim 1.

5. The filter member is formed in a cylindrical shape and is fitted into the recess.

2. A fluid-working machine according to claim 1.

6. The piston has a shaft portion that reciprocates within the cylinder and an opposing portion that is connected to the shaft portion and faces a sliding surface of the rotating shaft, The flow path portion penetrates the opposing portion along the axial direction, The recess penetrates the shaft portion along the axial direction and communicates with the flow path portion.

2. A fluid-working machine according to claim 1.

7. The axial length of the filter member is greater than the length of the flow path portion. A fluid-working machine according to claim 6.

8. The cylinders and the pistons are arranged at predetermined intervals in the circumferential direction of the rotation shaft.

2. A fluid-working machine according to claim 1.

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