JP6751547B2 - Sliding structure in hydraulic system, hydraulic pump, hydraulic motor, hydraulic system - Google Patents

Description

The present invention relates to a sliding structure in a hydraulic device, a hydraulic pump, a hydraulic motor, and a hydraulic device.

It is known that a solid lubricant is placed on the sliding surface. The solid lubricant is placed, for example, on the contact surface between one metal member and the other metal member. The solid lubricant suppresses the seizure phenomenon of the metal contact surface (that is, the deterioration of the metal contact surface) due to the direct contact between the metals.

As a related technique, Patent Document 1 describes that a solid lubricating film is arranged on a torque transmission surface. Further, Patent Document 2 describes that a solid lubricant is contained in the seal ring interposed between the rotating shaft and the housing.

Japanese Unexamined Patent Publication No. 2012-137137 Japanese Unexamined Patent Publication No. 6-24271

An object of the present invention is sliding in a hydraulic device, a hydraulic pump, a hydraulic motor, or a hydraulic device capable of maintaining the sealing characteristics (or sliding characteristics) on the sealing surface (or sliding surface) on which a large axial load acts. To provide the structure.

These objectives and other objectives and benefits of the present invention can be easily confirmed by the following description and accompanying drawings.

Hereinafter, means for solving the problem will be described using the numbers and codes used in the embodiment of the invention. These numbers and codes are added in parentheses for reference in order to show an example of the correspondence between the description of the claims and the mode for carrying out the invention. Therefore, the scope of claims should not be construed in a limited manner by the description in parentheses.

The hydraulic system of some embodiments comprises a barrel (50) and a valve plate (60). The barrel (50) is arranged within the housing (40). The barrel (50) is rotatable around a central axis (X axis). The barrel (50) includes a first sliding surface (72; 52) perpendicular to the central axis (X-axis). The valve plate (60) is fixed to the housing (40). The valve plate (60) includes a second sliding surface (62; 72') that contacts the first sliding surface (72; 52). The first sliding surface (72; 52) and the second sliding surface (62; 72') are oil-sealed surfaces. The first sliding surface (72; 52) and the second sliding surface (62; 72') are surfaces on which an axial load acts in a direction along the central axis (X axis). At least one sliding surface (in other words, the first sliding surface and the second sliding surface) of the first sliding surface (72; 52) and the second sliding surface (62; 72'). The sliding surface of any one of the surfaces, or both sliding surfaces) is the surface of the solid lubricating film (70).

The hydraulic system may further include a swash plate (80) fixed to the housing (40). The barrel (50) may include a hydraulic cylinder (54) having a piston (542), a cylinder chamber (543), and an outflow port (544). The valve plate (60) may include a high-pressure side port (66) capable of communicating with the outflow port (544) and a low-pressure side port (64) capable of communicating with the outflow port (544). The axial load may act on the solid lubricating film (70) asymmetrically with respect to the central axis (X-axis).

In the hydraulic system, the first sliding surface (72; 52) of the barrel may be formed with an annular groove (58) surrounding the outflow port (544).

In the hydraulic device, the second sliding surface (62; 72') of the valve plate may be formed with an annular groove surrounding the high pressure side port (66) and the low pressure side port (64). ..

In the hydraulic system, when the hardness of the barrel (50) is lower than the hardness of the valve plate (60), the first sliding surface (72; 52) has an annular groove surrounding the outflow port (544). It may be provided. When the hardness of the barrel (50) is higher than the hardness of the valve plate (60), the high pressure side port (66) and the low pressure side port (66) are placed on the second sliding surface (62; 72'). An annular groove may be provided surrounding 64).

In the hydraulic system, the swash plate sliding surface which is the sliding surface of the swash plate (80) with the piston (542) or the sliding surface of the piston (542) with the swash plate (80). A solid lubricating film (5426) may be arranged on at least one of the sliding surfaces of a piston.

The hydraulic system may further include a retainer (90) that rotates with the barrel (50) and a washer (100) that is arranged between the swash plate (80) and the retainer (90). .. On the surface of the washer (100), the surface of the swash plate (80) in contact with the washer (100), or the surface of the retainer (90) in contact with the washer (100). May have a solid lubricating film (102) arranged.

In the hydraulic system, the solid lubricating film (102) may be arranged on the surface of the washer (100) that contacts the swash plate and the surface that contacts the retainer (90). ..

In the hydraulic system, a surface sealing member including a rotating shaft (110) that rotates together with the barrel (50) and a third sliding surface that is fixed to the rotating shaft (110) and is perpendicular to the central axis (X axis). (114) and a receiving member (48) fixed to the housing (40) and having a fourth sliding surface in contact with the third sliding surface may be further provided. The third sliding surface and the fourth sliding surface may be surfaces on which an axial load in a direction along the central axis (X-axis) acts. At least one sliding surface of the third sliding surface and the fourth sliding surface may be the surface of the solid lubricating film (49).

The hydraulic pump of some embodiments is a hydraulic pump comprising the hydraulic system described in any of the paragraphs above.

The hydraulic motor of some embodiments is a hydraulic motor comprising the hydraulic system described in any of the paragraphs above.

The sliding structure in the hydraulic system of some embodiments comprises a first member (50; 100; 114; 542) and a second member (60; 90; 48; 80). The first member is rotatable around a central axis (X axis; Ct) and includes a first sliding surface (72, etc.) perpendicular to the central axis (X axis; Ct). The second member includes a second sliding surface (62, etc.) that contacts the first sliding surface. The first sliding surface and the second sliding surface are surfaces on which an axial load acts in a direction along the central axis (X axis; Ct). At least one sliding surface of the first sliding surface and the second sliding surface is the surface of the solid lubricating film (70; 102; 49; 5426).

In the sliding structure of the hydraulic device, the first sliding surface and the second sliding surface may be surfaces on which the axial load acts asymmetrically with respect to the central axis.

According to the present invention, a sliding structure in a hydraulic device, a hydraulic pump, a hydraulic motor, and a hydraulic device capable of maintaining the sealing characteristics (or sliding characteristics) on the sealing surface (or sliding surface) on which a large axial load acts Can be provided.

FIG. 1A is a side view of a fixing member and a rotating member, and is a diagram for explaining a problem recognized by the inventor. FIG. 1B is a cross-sectional view taken along the line AA of FIG. 1A. FIG. 2A is a side view of the fixing member and the rotating member, and is a diagram for explaining the problem recognized by the inventor. FIG. 2B is a cross-sectional view taken along the line BB of FIG. 2A. FIG. 2C is a side view of the fixing member and the rotating member, and is a diagram for explaining the problem recognized by the inventor. FIG. 3A is a schematic side view of the hydraulic system. FIG. 3B is a cross-sectional view taken along the line A1-A1 of FIG. 3A. FIG. 3C is a cross-sectional view taken along the line A1-A1 of FIG. 3A. FIG. 4A is a cross-sectional view taken along the line A1-A1 of FIG. 3A. FIG. 4B is a cross-sectional view taken along the line CC of FIG. 4A. FIG. 4C is a cross-sectional view taken along the line DD of FIG. 4A. FIG. 4D is a cross-sectional view taken along the line EE of FIG. 4A. FIG. 4E is an enlarged view of the region F of FIG. 4A. FIG. 4F is an enlarged view of the region F of FIG. 4A and shows a modified example. FIG. 4G is a diagram for explaining the operation of the hydraulic system. FIG. 5A is a schematic block diagram showing an example of a hydraulic pump. FIG. 5B is a schematic block diagram showing an example of a hydraulic motor. FIG. 6 is a cross-sectional view taken along the line A1-A1 of FIG. 3A.

Hereinafter, the sliding structures of the hydraulic device, the hydraulic pump, the hydraulic motor, and the hydraulic device will be described with reference to the accompanying drawings.

(Definition of important terms)
As used herein, "vertical" includes exactly 90 degrees and about 90 degrees. About 90 degrees includes angles of 85 degrees or more and 95 degrees or less.

(Definition of coordinate system)
The direction along the central axis of the rotating shaft is defined as the X axis. When the hydraulic system includes a barrel and a valve plate, the + X direction is defined as a direction along the X axis and from the barrel to the valve plate. The Z axis is an axis perpendicular to the X axis. The Y-axis is an axis perpendicular to the X-axis and the Z-axis.

(Issues recognized by the inventor)
1A and 1B are views for explaining a sliding surface on which a large axial load acts. FIG. 1A is a side view of the fixing member 10 and the rotating member 20. FIG. 1B is a cross-sectional view taken along the line AA of FIG. 1A.

The fixing member 10 is fixed to the housing, for example. The fixing member 10 includes, for example, a fixing plate 12. The rotating member 20 rotates around a central axis (X axis). In the example described in FIG. 1A, the rotating member 20 rotates in the R direction. The rotating member 20 includes, for example, a rotating plate 22. An axial load F, which is a compressive load, acts on the fixed member 10 and the rotating member 20 along the central axis (X-axis).

The fixing plate 12 includes a sliding surface that comes into contact with the rotating plate 22. Further, the rotating plate 22 includes a sliding surface that comes into contact with the fixing plate 12. An axial load acts on the sliding surface of the rotating plate 22 and the sliding surface of the fixing plate 12. A technique of plating a sliding surface with a soft metal is known in order to prevent a seizure phenomenon from occurring on a sliding surface on which an axial load acts.

The inventor has found that when a sliding surface on which a large axial load acts is plated with a soft metal, the plating wears severely. From the viewpoint of preventing the occurrence of seizure phenomenon, some wear of the plating is allowed. However, when the sliding surface on which a large axial load acts is the sealing surface, liquid leakage from the sealing surface occurs due to wear of the plating.

The inventor has set at least one of the sliding surfaces on which a large axial load acts as the surface of the solid lubricating film 14, so that liquid leakage from the sealing surface occurs due to wear of the sealing surface. Was found to be prevented. It overturns the common general technical wisdom that soft metal plating is applied to the sliding surface on which the axial load acts. In FIG. 1A, the gap between the surface of the solid lubricating film 14 and the surface of the rotating plate 22 is exaggerated. The gap is actually a minute gap. Further, in reality, the minute gaps are not uniform, and there is also a region where the surface of the solid lubricating film 14 and the surface of the rotating plate 22 come into contact with each other.

(Another issue recognized by the inventor)
2A to 2C are views for explaining a sliding surface on which an axial load asymmetrical with respect to the central axis acts. FIG. 2A is a side view of the fixing member 10 and the rotating member 20. FIG. 2B is a cross-sectional view taken along the line BB of FIG. 2A. FIG. 2C is a side view of the fixing member 10 and the rotating member 20.

With respect to FIGS. 2A to 2C, members having the same function as the members described with reference to FIGS. 1A and 1B are given the same drawing numbers. An axial load F1 acts on the lower portion of the fixed plate 12 (the portion located in the region Az (-) on the −Z direction side), and the lower portion of the rotating plate 22 (the region Az on the −Z direction side) ( An axial load F1 acts on the portion located at −). Further, an axial load F2 acts on the upper portion of the fixing plate 12 (the portion located in the region Az (+) on the + Z direction side), and the upper portion of the rotating plate 22 (the region Az (+) on the + Z direction side). Axial load F2 acts on the portion located in. It is assumed that the axial load F2 is smaller than the axial load F1 (in other words, it is assumed that an axial load asymmetric with respect to the central axis (X axis) acts on the sliding surface). ..

With reference to FIG. 2C, the axial load F2 acts on the distance between the lower portion of the fixed plate 12 on which the axial load F1 acts and the lower portion of the rotating plate 22 on which the axial load F1 acts. It is understood that the distance is smaller than the distance between the upper portion of the fixed plate 12 and the upper portion of the rotating plate 22 on which the axial load F2 acts.

For example, it is assumed that the surface of the fixing plate 12 is plated with a soft metal. The plating applied to the lower portion of the fixing plate 12 on which the axial load F1 acts wears more severely than the plating applied to the upper portion of the fixing plate 12 on which the axial load F2 acts. In other words, the amount of plating wear is asymmetric with respect to the central axis (X-axis).

The inventor found that when the sliding surface on which the axial load asymmetrical with respect to the central axis acts is the sealing surface, the amount of plating wear is asymmetrical, resulting in liquid leakage from the sealing surface. Was found to occur.

Further, the inventor has made the surface of the solid lubricating film 14 at least one of the sliding surfaces on which the axial load asymmetric with respect to the central axis acts, so that the amount of wear is asymmetric. It has been found that the occurrence of liquid leakage from the sealing surface is prevented.

The fixing member 10 and the rotating member 20 in FIGS. 1A to 2C are described for convenience in order to explain the problem recognized by the inventor. Therefore, the fixing member 10 and the rotating member 20 shown in FIGS. 1A to 2C do not show known techniques before the application of the present application.

(Overview of hydraulic system)
An outline of the hydraulic device 30 (device operated by hydraulic pressure) will be described with reference to FIGS. 3A and 3B. FIG. 3A is a schematic side view of the hydraulic system. Further, FIG. 3B is a cross-sectional view taken along the line A1-A1 of FIG. 3A.

The hydraulic device 30 includes a housing 40, a barrel 50, and a valve plate 60.

The barrel 50 is arranged in the housing 40. The barrel 50 is rotatable around a central axis (X-axis) and includes a hydraulic cylinder 54, a solid lubricating film 70, and a first sliding surface 72 perpendicular to the central axis (X-axis).

The valve plate 60 is fixed directly or indirectly to the housing. The valve plate 60 includes a second sliding surface 62 that comes into contact with the first sliding surface 72. It should be noted that "contact" includes not only constant contact but also occasional contact.

The first sliding surface 72 and the second sliding surface 62 are oil sealing surfaces that seal between the barrel 50 and the valve plate 60 so that oil does not leak. Further, an axial load (F1, F2, etc.) acts on the first sliding surface 72 in the direction along the central axis (X axis) via the valve plate 60 or oil, and the second sliding surface 62 is affected. Axial loads (F1, F2, etc.) act in the direction along the central axis (X-axis) via the barrel 50 or oil. The axial load (F1, F2, etc.) is an axial load (eg, F1> F2) that is asymmetric with respect to the central axis (X-axis).

In the example shown in FIG. 3B, the first sliding surface 72 is the surface of the solid lubricating film 70. Alternatively or additionally, the second sliding surface may be the surface of the solid lubricating film 70. The solid lubricating film 70 is provided on the base material (for example, a metal base material) constituting the barrel 50 and the base material (for example, a metal base material) constituting the valve plate 60, whichever has the lower hardness. May be done.

FIG. 3C shows an example in which the second sliding surface 72'is the surface of the solid lubricating film 70'. With respect to FIG. 3C, members having the same function as the members described with reference to FIG. 3B are given the same drawing numbers.

In the example shown in FIG. 3C, the barrel 50 includes a first sliding surface 52 perpendicular to the central axis (X axis). The valve plate 60 includes a second sliding surface 72'that contacts the first sliding surface 52. It should be noted that "contact" includes not only constant contact but also occasional contact.

The first sliding surface 52 and the second sliding surface 72'are oil sealing surfaces that seal between the barrel 50 and the valve plate 60 so that oil does not leak. Further, an axial load (F1, F2, etc.) acts on the first sliding surface 52 in the direction along the central axis (X axis) via the valve plate 60 or oil, and the second sliding surface 72' Axial loads (F1, F2, etc.) act in the direction along the central axis (X-axis) via the barrel 50 or oil. The axial load (F1, F2, etc.) is an axial load (eg, F1> F2) that is asymmetric with respect to the central axis (X-axis). In the example shown in FIG. 3C, the second sliding surface 72'is the surface of the solid lubricating film 70.

In the example described in FIG. 3B or FIG. 3C, the first sliding surface or the second sliding surface is the surface of the solid lubricating film 70. Therefore, even when an axial load acts on the first sliding surface and the second sliding surface, the sealing characteristic between the first sliding surface and the second sliding surface is maintained.

In the example described in FIG. 3B or FIG. 3C, the first sliding surface or the second sliding surface is the surface of the solid lubricating film 70. Therefore, even when an axial load asymmetric with respect to the central axis (X-axis) acts on the first sliding surface and the second sliding surface, the first sliding surface and the second sliding surface The sealing properties between and are maintained.

(More detailed description of hydraulic system)
The hydraulic device 30 will be described in more detail with reference to FIG. 4A. FIG. 4A is a cross-sectional view taken along the line A1-A1 of FIG. 3A. With respect to FIG. 4A, members having the same function as the members described with reference to FIG. 3B are given the same drawing numbers.

Hereinafter, the case where the hydraulic device 30 is included in the hydraulic pump will be described, but the hydraulic device 30 may be included in the hydraulic motor.

The hydraulic device 30 includes a housing 40, a barrel 50, a valve plate 60, a swash plate 80, a retainer 90, a washer 100, a rotary shaft 110, an elastic member 120, a bearing 130, and a second bearing 140. Equipped with.

(Housing 40)
The housing 40 includes, for example, a side wall 40A, a first end wall 40B, and a second end wall 40C. The first end wall 40B is fixed to one end of the side wall 40A, and the second end wall 40C is fixed to the other end of the side wall 40A. The side wall 40A has, for example, a cylindrical shape. The first end wall 40B includes a first oil passage 44 communicating with the first pipeline 144 and a second oil passage 46 communicating with the second pipeline 146. The oil is supplied to the hydraulic device 30 from the first pipeline 144. Further, the oil is discharged from the hydraulic device 30 to the second pipeline 146. The hydraulic device 30 functions as a part of a hydraulic pump that supplies oil to the second pipeline 146.

(Valve plate 60)
The valve plate 60 is fixed to the first end wall 40B of the housing. The valve plate 60 includes a low pressure side port 64 and a high pressure side port 66 (if necessary, see FIG. 4B, which is a sectional view taken along the line CC of FIG. 4A), and a second sliding surface 62. The low pressure side port 64 communicates with the first oil passage 44 of the first end wall 40B of the housing. The high pressure side port 66 communicates with the second oil passage 46.

(Barrel 50)
The barrel 50 is arranged in the housing 40. The barrel 50 is rotatable around the central axis (X-axis), and has a first hydraulic cylinder 54-1 to a ninth hydraulic cylinder 54-9 (note that, in FIG. 4A, a first hydraulic cylinder 54-1 and a first hydraulic cylinder 54-1). (5) Only the hydraulic cylinder 54-5 is shown), the solid lubricating film 70, and the first sliding surface 72 perpendicular to the central axis (X-axis) are provided. The solid lubricating film 70 is provided at the end portion of the barrel 50 on the + X direction side (that is, the end portion on the valve plate side). Therefore, the surface of the solid lubricating film 70 is the first sliding surface 72. In the examples shown in FIGS. 4A and 4B, the number of hydraulic cylinders is nine. However, the number of hydraulic cylinders is not limited to nine. The number of hydraulic cylinders is any number of 1 or more (usually an odd number).

The first hydraulic cylinder 54-1 includes a first piston 542-1, a first cylinder chamber 543-1 and a first outflow port 544-1. In the first cylinder chamber 543-1, when the first outflow port 544-1 and the low pressure side port 64 of the valve plate communicate with each other, the first pipe line 144, the first oil passage 44, and the low pressure side port 64 Receives oil supplied through the first outflow port 544-1. In the first cylinder chamber 543-1, when the first outflow port 544-1 and the high pressure side port 66 of the valve plate communicate with each other, the first outflow port 544-1, the high pressure side port 66, and the second oil passage 46 Oil is discharged to the second pipeline 146 via and. FIG. 4C is a cross-sectional view taken along the line DD of FIG. 4A. In addition to the first outflow port 544-1 of the first hydraulic cylinder 54-1, the second hydraulic cylinders 54-2 to the ninth hydraulic cylinder 54- The second outflow port 544-2 to the ninth outflow port 544-9 corresponding to each of 9 are shown.

The first piston 542-1 slides with respect to the cylinder block in the direction along the central axis (X axis). When the first piston 542-1 slides in the + X direction, that is, in the direction approaching the valve plate 60, the volume of the first cylinder chamber 543-1 is reduced, and the volume of the first cylinder chamber 543-1 is reduced from the first cylinder chamber 543-1 to the second pipeline 146. Oil is discharged. When the first piston 542-1 slides in the −X direction, that is, in the direction away from the valve plate 60, the volume of the first cylinder chamber 543-1 is expanded from the first pipeline 144 to the first cylinder chamber 543-1. , Oil is supplied.

The distal end portion 5422-1 (the end far from the valve plate 60) of the first piston 542-1 includes a spherical portion. The first shoe 546-1 is connected to the spherical portion. The first shoe 546-1 is rotatably connected to the spherical portion. The first shoe 546-1 is in contact with the swash plate 80. Further, the first shoe 546-1 is restrained by the retainer 90 so that the distance from the swash plate is within a certain range. The central axis of the retainer 90 is defined as Ct. The first shoe 546-1 and the retainer 90 rotate around the central axis Ct as the barrel 50 rotates. The first shoe 546-1 slides on the surface of the swash plate 80 as the barrel 50 rotates. FIG. 4D is a cross-sectional view taken along the line EE of FIG. 4A, showing the second shoe 546-2 to the ninth shoe 546-9 in addition to the first shoe 546-1.

FIG. 4A shows a state in which the first shoe 546-1 is located farthest from the valve plate 60 (that is, the first shoe 546-1 is located most in the −X direction). .. In this state, the first piston 542-1 is in the most retracted position in the −X direction, and the volume of the first cylinder chamber 543-1 is the maximum. As the volume of the first cylinder chamber 543-1 increases, oil is supplied to the first cylinder chamber 543-1 through the first outflow port 544-1 and the low pressure side port 64.

As the barrel 50 rotates, the first shoe 546-1 slides on the surface of the swash plate 80. When the first shoe 546-1 slides on the surface of the swash plate 80 and the first shoe 546-1 moves in the + X direction, the volume of the first cylinder chamber 543-1 becomes smaller. As the volume of the first cylinder chamber 543-1 becomes smaller, oil is supplied from the first cylinder chamber 543-1 to the second pipeline 146 via the first outflow port 544-1 and the high pressure side port 66. ..

The configuration of each hydraulic cylinder of the second hydraulic cylinder 54-2 to the ninth hydraulic cylinder 54-9 is the same as the configuration of the first hydraulic cylinder 54-1. The configuration of each shoe of the second shoe 546-2 to the ninth shoe 546-9 is the same as the configuration of the first shoe 546-1. Therefore, the description of the second hydraulic cylinder 54-2 to the ninth hydraulic cylinder 54-9 and the second shoe 546-2 to the ninth shoe 546-9 will be omitted.

In FIG. 4A, an axial load in the + X direction acts on the upper portion of the barrel 50 (the portion located in the region Azz (+) on the + Z side) due to the hydraulic pressure in the first cylinder chamber 543-1. .. An axial load in the + X direction may be applied to the barrel 50 by a pressing mechanism such as the elastic member 120. The + X-direction axial load acting on the upper portion of the barrel 50 is defined as the axial load F2. An axial load F2 acts on the second sliding surface 62 of the valve plate 60 by being pushed by the barrel 50. As a reaction to the action of the axial load F2 on the second sliding surface 62, the axial load F2 acts on the first sliding surface 72 of the barrel 50.

In FIG. 4A, an axial load in the + X direction acts on the lower portion of the barrel 50 (the portion located in the region Azz (-) on the −Z side) due to the hydraulic pressure in the fifth cylinder chamber 543-5. ing. An axial load in the + X direction may be applied to the barrel 50 by a pressing mechanism such as the elastic member 120. The + X axial load acting on the lower portion of the barrel 50 is defined as the axial load F1. Since the hydraulic pressure in the fifth cylinder chamber 543-5 is larger than the hydraulic pressure in the first cylinder chamber 543-1, the axial load F1 is larger than the axial load F2. An axial load F1 acts on the second sliding surface 62 of the valve plate 60 by being pushed by the barrel 50. As a reaction to the action of the axial load F1 on the second sliding surface 62, the axial load F1 acts on the first sliding surface 72 of the barrel 50.

In the hydraulic system, the pressure (surface pressure) due to the axial load acting on the first sliding surface 72 and the second sliding surface 62 is very large. For example, the axial pressure (surface pressure) acting on the first sliding surface 72 or the second sliding surface 62 may be 5 MPa or more due to the axial load. The first sliding surface 72 and the second sliding surface 62 are worn by sliding under the action of pressure (surface pressure) due to an axial load. In the embodiment, since the first sliding surface 72 is the surface of the solid lubricating film 70, the high sliding characteristics (high seizure resistance) of the solid lubricating film 70 alleviate wear. High sliding characteristics mean that the coefficient of friction is small and the seizure resistance is excellent. Due to its crystal structure, the solid lubricating film 70 is easy to slip between layers with weak bonding force, and withstands a load in the compression direction on the surface with strong bonding force. Therefore, it has a feature that the coefficient of friction is small and the seizure resistance is excellent.

Further, in the hydraulic system of the embodiment, the pressure (surface pressure) due to the axial load acting on the first sliding surface 72 and the second sliding surface 62 is asymmetric with respect to the Z axis. The first sliding surface 72 and the second sliding surface 62 are asymmetrically worn by the pressure (surface pressure) due to the asymmetric axial load. In the embodiment, since the first sliding surface 72 is the surface of the solid lubricating film 70, asymmetrical wear is alleviated by the high sliding characteristics of the solid lubricating film 70.

(Swash plate 80, retainer 90, washer 100)
The swash plate 80 is directly or indirectly fixed to the housing 40. In FIG. 4A, the description of the fixing mechanism of the swash plate 80 to the housing 40 is omitted in order to avoid complication of the drawing. The swash plate 80 includes a sliding surface (shoe sliding surface) on which the first shoe 546-1 to the ninth shoe 546-9 slide. The first shoe 546-1 to the ninth shoe 546-9 may be omitted. When the first shoe 546-1 to the ninth shoe 546-9 are omitted, the swash plate 80 is a sliding surface (piston sliding surface) on which the first piston 542-1 to the ninth piston 542-9 slide. To be equipped.

The retainer 90 is a member that holds the washer 100. A washer 100 is arranged between the swash plate 80 and the retainer 90. The washer 100 is a ring-shaped member. The washer 100 is slidable with respect to the retainer 90 and slidable with respect to the swash plate 80. An axial load acts on the surface of the washer 100 in the direction along the central axis Ct. The axial load is an axial load that is asymmetric with respect to the central axis Ct.

FIG. 4E is an enlarged view of the region F of FIG. 4A. Referring to FIG. 4E, a solid lubricating film 102 is provided on the surface of the washer 100 (in other words, the surface of the washer is the surface of the solid lubricating film 102). In the example shown in FIG. 4E, the solid lubricating film 102 is provided on the surface of the washer 100 on the side in contact with the retainer 90. Alternatively, the solid lubricating film 102 may be provided on the surface of the washer 100 that comes into contact with the swash plate 80. In the example shown in FIG. 4E, the solid lubricating film 102 is provided on the surface of the washer 100. Alternatively or additionally, a solid lubricating film 102 may be provided on the surface of the retainer 90 in contact with the washer 100. Alternatively or additionally, a solid lubricating film 102 may be provided on the surface of the swash plate 80 in contact with the washer 100.

It is easier to apply the solid lubricating film 102 to the surface of the washer 100 than to apply the solid lubricating film 102 to the surface of the retainer 90 or the surface of the swash plate 80. The solid lubricating film 102 may be provided on both sides of the washer 100 (that is, both the surface of the washer 100 that contacts the retainer 90 and the surface of the washer 100 that contacts the swash plate 80). preferable. This is because, for example, even if the solid lubricating film between the washer 100 and the retainer 90 is worn and seizure occurs between the washer 100 and the retainer 90, between the washer 100 and the swash plate 80. This is because excessive seizure can be prevented by causing slippage. FIG. 4F shows an example in which the solid lubricating film 102 is provided on both sides of the washer 100.

In the embodiment, the solid lubricating film 102 is provided on at least one surface of the washer 100, the surface of the swash plate 80 in contact with the washer 100, or the surface of the retainer 90 in contact with the washer 100. Therefore, the wear of the washer, the swash plate, or the retainer due to the action of the pressure (surface pressure) due to the axial load is alleviated. Further, the asymmetrical wear of the washer, swash plate, or retainer due to the action of pressure (surface pressure) due to the asymmetric axial load is alleviated.

(Rotating shaft 110)
The rotary shaft 110 is a rotary member that transmits power from a drive device (not shown in FIG. 4A) to the barrel 50. The engaging portion 112 of the rotating shaft 110 and the engaging portion 55 of the barrel 50 are engaged with each other so as to limit or prohibit relative rotation around the X axis. The engaging portion 112 is, for example, a convex portion formed on the outer peripheral surface of the rotating shaft. The engaging portion 55 is, for example, a recess formed on the inner peripheral surface of the barrel 50. As the rotating shaft 110 rotates about the X-axis, the barrel 50 rotates about the X-axis.

The rotary shaft 110 may urge the barrel in the + X direction (that is, the direction in which the valve plate 60 is pressed). In the example described in FIG. 4A, the rotating shaft 110 urges the barrel 50 toward the valve plate 60 via an elastic member 120 (eg, a coil spring). In the example described in FIG. 4A, the elastic member 120 is arranged between the tip of the rotating shaft 110 and the receiving portion 56 provided on the barrel 50.

(Bearings 130, 140)
The bearing 130 is a bearing that rotatably supports the rotary shaft 110. The second bearing 140 is a bearing that rotatably supports the barrel 50 with respect to the housing 40. The second bearing 140 is arranged between the barrel 50 and the housing 40 (specifically, the side wall 40A of the housing 40).

(Circular groove 58)
In the embodiment, the end surface (that is, the first sliding surface 72) of the barrel 50 on the valve plate 60 side has a first outflow port 544-1 to a ninth outflow port 544-9 (in other words, a plurality of outflow ports). An annular groove 58 is provided so as to surround all the outflow ports). The depth of the annular groove 58 may exceed the thickness of the solid lubricating film 70 and reach the base material of the barrel 50. Further, a radial groove communicating with the annular groove 58 may be provided. The annular groove and the radial groove control the pressure gradient of the oil leaking from the gap between the first sliding surface 72 and the second sliding surface 62. By controlling the pressure gradient until the internal pressure of the housing (case pressure) is reached, it is possible to balance the rotation of the barrel 50.

In the embodiment, the presence of the solid lubricating film 70 prevents seizure. In addition to maintaining the sealing function and reducing the risk of oil leakage by preventing seizure, the presence of the annular groove 58 maintains the rotational balance. That is, oil leakage is effectively suppressed by the synergistic effect of the effect of preventing seizure by the solid lubricating film 70, the effect of reducing the risk of oil leakage, and the effect of maintaining the rotational balance by the annular groove 58.

The annular groove 58 may be provided on at least one surface of the two surfaces in contact with each other (in other words, one or both surfaces of the two surfaces in contact with each other). .. When the annular groove 58 is provided on the surface of the member having a low hardness, the risk of damaging the surface of another member (member having a high hardness) due to the edge of the annular groove 58 is reduced. Further, by providing the solid lubricating film on the surface of the member on the low hardness side, when the solid lubricating film is worn and the member on the low hardness side is exposed, the other member (member on the high hardness side) The risk of surface damage is reduced.

In the embodiment shown in FIG. 4A, the annular groove 58 is provided on the barrel side. Alternatively or additionally, the annular groove 58 may be provided on the valve plate 60 side (specifically, the second sliding surface 62). When the annular groove 58 is provided on the valve plate 60 side, the annular groove is arranged so as to surround the high pressure side port 66 and the low pressure side port 64.

(Operation of hydraulic system)
Next, the operation of the hydraulic system will be described with reference to FIGS. 4A and 4G. FIG. 4G is a diagram schematically showing the position and state of the hydraulic cylinder.

First, the rotating shaft 110 is rotated by power from a driving device (not shown in FIGS. 4A and 4G). The rotation of the rotating shaft 110 is transmitted to the barrel 50 via the engaging portion 112 and the engaging portion 55. That is, the barrel 50 rotates about the X-axis together with the rotating shaft 110.

In the first state, the hydraulic cylinder 54 (the hydraulic cylinder of any one of the first hydraulic cylinders 54-1 to the ninth hydraulic cylinder 54-9) is located at the most + Z direction side, that is, P1 in FIG. 4G. It is assumed that it exists at the position (first position). At this time, the volume V1 of the cylinder chamber 543 of the hydraulic cylinder 54 is the maximum. In the first state, the cylinder chamber 543 communicates with the outflow port 544 and communicates with at least one of the low pressure side port 64 and the high pressure side port 66. Alternatively, in the first state, the cylinder chamber 543 may communicate with the outflow port 544 and not with either the low pressure side port 64 or the high pressure side port 66.

Second, the barrel 50 rotates around the X axis in the R direction shown in FIG. 4G, so that the hydraulic cylinder 54 moves to the position (second position) of P2 (second state). At this time, the volume V2 of the cylinder chamber 543 of the hydraulic cylinder 54 is smaller than the volume V1. In the second state, the cylinder chamber 543 communicates with the outflow port 544, the high pressure side port 66, the second oil passage 46, and the second pipeline 146. As the volume of the cylinder chamber 543 is reduced, oil is discharged into the second pipeline 146 (that is, the hydraulic device functions as a hydraulic pump).

Third, the barrel 50 rotates around the X axis in the R direction shown in FIG. 4G, so that the hydraulic cylinder 54 moves to the position (third position) of P3 (third state). At this time, the volume V3 of the cylinder chamber 543 of the hydraulic cylinder 54 is smaller than the volume V2. In the third state, the cylinder chamber 543 communicates with the outflow port 544, the high pressure side port 66, the second oil passage 46, and the second pipeline 146. As the volume of the cylinder chamber 543 is reduced, oil is discharged to the second pipeline 146.

Fourth, as the barrel 50 rotates around the X axis in the R direction shown in FIG. 4G, the hydraulic cylinder 54 moves to the position of P4 (fourth position) (fourth state).

Fifth, as the barrel 50 rotates around the X-axis in the R direction shown in FIG. 4G, the hydraulic cylinder 54 moves to the position (fifth position) of P5 (fifth state).

In the fourth state and the fifth state, the oil is discharged from the cylinder chamber 543 to the second pipe line 146 as in the second state and the third state. In the fifth state, the volume V5'of the cylinder chamber 543 is the minimum.

Sixth, as the barrel 50 rotates around the X axis in the R direction shown in FIG. 4G, the hydraulic cylinder 54 moves to the position (sixth position) of P6 (sixth state). At this time, the volume V6 of the cylinder chamber 543 of the hydraulic cylinder 54 is larger than the volume V5'. In the sixth state, the cylinder chamber 543 communicates with the outflow port 544, the low pressure side port 64, the first oil passage 44, and the first pipeline 144. As the volume of the cylinder chamber 543 increases, oil is supplied from the first pipeline 144 to the cylinder chamber 543.

Seventh, as the barrel 50 rotates around the X axis in the R direction shown in FIG. 4G, the hydraulic cylinder 54 moves to the position of P7 (seventh position) (seventh state).

Eighth, as the barrel 50 rotates around the X axis in the R direction shown in FIG. 4G, the hydraulic cylinder 54 moves to the position of P8 (eighth position) (eighth state).

Ninth, as the barrel 50 rotates around the X axis in the R direction shown in FIG. 4G, the hydraulic cylinder 54 moves to the position of P9 (9th position) (9th state).

Tenth, as the barrel 50 rotates around the X axis in the R direction shown in FIG. 4G, the hydraulic cylinder 54 moves to the position of P1 (first position) (returns to the first state). ..

In the seventh state, the eighth state, and the ninth state, oil is supplied from the first pipe line 144 to the cylinder chamber 543 as in the sixth state.

As described above, as the rotary shaft 110 and the barrel 50 rotate, oil is supplied from the first pipeline 144 to the cylinder chamber 543 of the hydraulic cylinder 54, and from the cylinder chamber 543 of the hydraulic cylinder 54 to the second pipeline 146. Oil is discharged.

(Hydraulic pump)
FIG. 5A is a schematic block diagram showing an example of a hydraulic pump.

In the example described in FIG. 5A, the hydraulic pump includes a hydraulic device 30. The hydraulic device 30 has the same configuration as the hydraulic device 30 described in the above-described embodiment.

The hydraulic pump includes a hydraulic device 30, a drive device 200, a rotary shaft 110, a first line 144, and a second line 146. The driving force of the driving device 200 is transmitted to the rotating shaft 110. The rotating shaft 110 rotates about a rotation axis. As the rotary shaft 110 rotates, oil is supplied to the hydraulic device 30 from the first pipeline 144, and oil is discharged from the hydraulic device 30 to the second pipeline 146 according to the above-mentioned operating principle. The oil flowing through the second line 146 does the work and operates the load 300. The oil that operates the load 300 is supplied to the hydraulic device 30 again via the first pipeline 144.

When the drive device 200 is an electric motor and the load 300 is an actuator, the hydraulic pump constitutes an electro-hydraulic actuator.

(Hydraulic motor)
FIG. 5B is a schematic block diagram showing an example of a hydraulic motor. The hydraulic device 30 has the same configuration as the hydraulic device 30 described in the above-described embodiment. The hydraulic motor includes a hydraulic device 30, a rotary shaft 110, a first line 144, and a second line 146. In the hydraulic motor, the hydraulic pump 400 has a function of circulating oil. The oil supplied by the hydraulic pump 400 to the hydraulic system 30 via the first pipeline 144 does the work of rotating the barrel 50 and the rotary shaft 110. The oil after work is supplied to the hydraulic pump 400 via the second pipeline 146.

(Modification)
FIG. 6 shows a modified example of the hydraulic system. FIG. 6 is a vertical sectional view of the hydraulic system. With respect to FIG. 6, members having the same function as the members described with reference to FIG. 4A are given the same drawing numbers.

The example shown in FIG. 6 differs from the example shown in FIG. 4A in that the shoe is not arranged at the tip of the piston 542. In the example shown in FIG. 6, the tip portion 5424-1 of the first piston 542-1 comes into direct contact with the swash plate 80. Similarly, the tips of the second piston 542-2 to the ninth piston 542-9 each come into direct contact with the swash plate 80.

The X-axis axial load acting on the tip of the first piston 542-1 is different from the X-axis axial load acting on the tip of the fifth piston 542-5. That is, in the example shown in FIG. 6, the shoe is not arranged at the tip end portion of the piston 542, but the axial load acting on the tip end portion of the piston is the same as the example shown in FIG. 4A.

In the example shown in FIG. 6, a solid lubricating film 5426-1 is provided at the tip of the first piston 542-1. The solid lubricating film 5426-2 to the solid lubricating film 5426-9 are also provided at the tips of the second piston 542-2 to the ninth piston 542-9, respectively. Alternatively or additionally, a solid lubricating film may be provided on the surface of the swash plate 80, at least on the surface of the portion in contact with the tip of the piston.

In the example shown in FIG. 6, the solid lubricating film 5426 is provided on the surface of the piston tip or the surface of the swash plate 80 in contact with the piston tip. Therefore, the wear of the piston tip or the swash plate due to the action of the axial load is alleviated.

In the example shown in FIG. 6, the shoe does not exist. In this case, the retainer 90 is unnecessary. When the retainer is not provided, for example, a spring (not shown) is inserted into the cylinder chamber 543 to bring the tip of the piston into contact with the swash plate 80 (in FIG. 6, in order to avoid complication of the drawing, the above mechanism is used. , Not shown).

In the example shown in FIG. 6, the surface sealing member 114 is fixed to the rotating shaft 110. An O-ring 116 is arranged between the surface sealing member 114 and the rotating shaft 110. The surface sealing member 114 rotates around the X-axis together with the rotating shaft 110. The rear end surface (end surface on the −X direction side) of the surface seal member 114 is in surface contact with the front end surface (end surface on the + X direction side) of the receiving member 48 directly or indirectly fixed to the housing 40. In the example described in FIG. 6, the receiving member 48 is fixed to the second end wall 40C of the housing. An axial load acts on the rear end surface of the surface seal member 114 and the front end surface of the receiving member 48 in the direction along the central axis (X axis).

In the example described in FIG. 6, a solid lubricating film 49 is provided on the front end surface of the receiving member 48 (in other words, the front end surface of the receiving member is the surface of the solid lubricating film 49). Alternatively or additionally, a solid lubricating film 49 may be provided on the rear end surface of the surface sealing member 114.

In the embodiment, the solid lubricating film 49 is provided on at least one surface of the surface of the receiving member 48 and the surface of the surface sealing member 114. Therefore, the wear of the receiving member 48 and the surface sealing member 114 due to the action of the pressure (surface pressure) due to the axial load is alleviated.

In the example shown in FIG. 6, the receiving member 48 is an annular member. Similarly, the surface seal member 114 is an annular member. Further, the front end surface of the receiving member 48 and the rear end surface of the surface sealing member 114 are sealing surfaces for preventing oil leakage.

(Solid lubricant film)
The solid lubricating film in the embodiment may be composed of a powder having a solid lubricating action and a base material as a binder. Examples of the powder having a solid lubricating action include inorganic materials such as graphite, boron nitride, molybdenum disulfide, zinc disulfide and copper disulfide, and organic materials such as polytetrafluoroethylene (PTFE) and graphite fluoride. It is possible to use materials. The inorganic solid lubricant may have, for example, a structure in which flat plate crystals are lined up in layers and exhibit a lubricating action by sliding between layers in the layered structure. On the other hand, in an organic solid lubricant, a lubricating action may be exhibited by a small surface energy caused by a fluorine atom. A deflick coat (registered trademark) may be used as the solid lubricating film.

The thickness of the solid lubricating film is preferably 3 μm or more and 20 μm or less. If the thickness is less than 3 μm, the film may be destroyed by the axial load. If the thickness is larger than 20 μm, the shape (flatness) of the film is not maintained and liquid leakage may occur.

The surface on which the solid lubricating film is provided is preferably the surface of a member having a low hardness among the surfaces in contact with each other. However, if it is unlikely that the base material supporting the solid lubricating film will be exposed due to wear of the solid lubricating film, the solid lubricating film may be provided on the surface of the member having a higher hardness.

In the embodiment, deterioration of the sealing surface (or sliding surface) can be suppressed by arranging the solid lubricating film on the sliding surface (or sliding surface) which is the sealing surface on which the axial load acts. It is possible. By suppressing the deterioration of the sealing surface (or sliding surface), the performance of the hydraulic system is effectively maintained. In the embodiment, even when a high axial load acts on the sealing surface (or sliding surface), or when an asymmetric axial load acts on the sealing surface (or sliding surface), the sealing surface is concerned. By arranging the solid lubricating film on (or the sliding surface), it is possible to suppress the deterioration of the sealing surface (or sliding surface). In the embodiment, even when an irregular load acts on the sealing surface (or sliding surface) due to the start of operation of the hydraulic system, the stop of operation, acceleration / deceleration of the rotating shaft, etc. By arranging the solid lubricating film on the surface), deterioration of the sealing surface (or sliding surface) can be suppressed.

In the embodiment, by arranging the solid lubricating film on the sealing surface (or sliding surface) on which the axial load acts, the discharge pressure (hydraulic pressure in the second pipeline 146) and the peripheral speed (rotational speed (rotational speed of the barrel)). ) And the value of the product of the diameter of the sliding surface) is 1.2 × 10 ³ MPa · m / s or more, and it is possible to realize an ultra-high output hydraulic device. In the embodiment, at least one sliding surface (in other words, the first sliding surface and the first sliding surface) of the first sliding surface on the barrel side and the second sliding surface on the valve plate side on which the axial load acts. By using either one of the two sliding surfaces or both sliding surfaces as the surface of the solid lubricating film, the value of the product of the discharge pressure and the peripheral speed can be changed to 2. It is possible to realize an ultra-high output hydraulic device of 3 × 10 ³ MPa · m / s or more.

The present invention is not limited to each of the above embodiments, and it is clear that each embodiment can be appropriately modified or modified within the scope of the technical idea of the present invention. In addition, the various techniques used in each embodiment or modification can be applied to other embodiments or modifications as long as there is no technical contradiction.

10: Fixing member 12: Fixing plate 14: Solid lubricating film 20: Rotating member 22: Rotating plate 30: Hydraulic device 40: Housing 40A: Side wall 40B: First end wall 40C: Second end wall 44: First oil passage 46 : Second oil passage 48: Receiving member 49: Solid lubricating film 50: Barrel 52: First sliding surface 54: Hydraulic cylinder 55: Engaging part 56: Receiving part 58: Annulus groove 60: Valve plate 62: Second sliding Moving surface 64: Low pressure side port 66: High pressure side port 70: Solid lubricating film 70': Solid lubricating film 72: First sliding surface 72': Second sliding surface 80: Slanted plate 90: Retainer 100: Washer 102: Solid lubrication film 110: Rotating shaft 112: Engaging part 114: Surface sealing member 116: O-ring 120: Elastic member 130: Bearing 140: Second bearing 144: First pipeline 146: Second pipeline 200: Drive device 300 : Load 400: Hydraulic pump 542: Piston 543: Cylinder chamber 544: Outflow port 546: Shoe 5422: Distal end 5426: Solid lubricating film

Claims (11)

A barrel that is located in the housing, is rotatable around a central axis, and has a first sliding surface perpendicular to the central axis.
A valve plate fixed to the housing and provided with a second sliding surface in contact with the first sliding surface.
It is provided with a swash plate fixed to the housing.
The first sliding surface and the second sliding surface are oil-sealed surfaces.
The first sliding surface and the second sliding surface are surfaces on which an axial load acts in a direction along the central axis.
At least one sliding surface of the first sliding surface and the second sliding surface is a surface of a solid lubricating film.
The barrel comprises a hydraulic cylinder having a piston, a cylinder chamber, and an outflow port.
The valve plate includes a high-pressure side port that can communicate with the outflow port and a low-pressure side port that can communicate with the outflow port.
The axial load acts on the solid lubricating film asymmetrically with respect to the central axis.
When the hardness of the barrel is lower than the hardness of the valve plate, an annular groove surrounding the outflow port is provided on the first sliding surface.
When the hardness of the barrel is higher than the hardness of the valve plate, the hydraulic device is provided with an annular groove surrounding the high pressure side port and the low pressure side port on the second sliding surface. The hydraulic device according to claim 1, wherein an annular groove surrounding the outflow port is formed on the first sliding surface of the barrel. The hydraulic device according to claim 1, wherein an annular groove surrounding the high-pressure side port and the low-pressure side port is formed on the second sliding surface of the valve plate. A solid lubricating film is arranged on at least one of the swash plate sliding surface which is a sliding surface with the piston in the swash plate or the piston sliding surface which is a sliding surface with the swash plate in the piston. The hydraulic device according to any one of claims 1 to 3. A retainer that rotates with the barrel,
Further provided with a washer disposed between the swash plate and the retainer.
Claims 1 to 3 in which a solid lubricating film is arranged on at least one surface of the washer, the surface of the swash plate in contact with the washer, or the surface of the retainer in contact with the washer. The hydraulic device according to any one of the above. The hydraulic device according to claim 5, wherein the solid lubricating film is arranged on the surface of the washer that contacts the swash plate and the surface that contacts the retainer. A rotating shaft that rotates with the barrel,
A surface sealing member fixed to the rotating shaft and provided with a third sliding surface perpendicular to the central axis.
Further provided with a receiving member fixed to the housing and having a fourth sliding surface in contact with the third sliding surface.
The third sliding surface and the fourth sliding surface are surfaces on which an axial load in a direction along the central axis acts.
The hydraulic device according to any one of claims 1 to 6, wherein the third sliding surface and at least one sliding surface of the fourth sliding surface are surfaces of a solid lubricating film. A barrel that is located in the housing, is rotatable around a central axis, and has a first sliding surface perpendicular to the central axis.
A valve plate fixed to the housing and provided with a second sliding surface in contact with the first sliding surface.
The swash plate fixed to the housing and
A retainer that rotates with the barrel,
A washer arranged between the swash plate and the retainer is provided.
The first sliding surface and the second sliding surface are oil-sealed surfaces.
The first sliding surface and the second sliding surface are surfaces on which an axial load acts in a direction along the central axis.
At least one sliding surface of the first sliding surface and the second sliding surface is a surface of a solid lubricating film.
The barrel comprises a hydraulic cylinder having a piston, a cylinder chamber, and an outflow port.
The valve plate includes a high-pressure side port that can communicate with the outflow port and a low-pressure side port that can communicate with the outflow port.
The axial load acts on the solid lubricating film asymmetrically with respect to the central axis.
A hydraulic device in which a solid lubricating film is arranged on at least one surface of the washer, the surface of the swash plate in contact with the washer, or the surface of the retainer in contact with the washer. The hydraulic device according to claim 8, wherein the solid lubricating film is arranged on the surface of the washer that contacts the swash plate and the surface that contacts the retainer. A hydraulic pump comprising the hydraulic device according to any one of claims 1 to 9. A hydraulic motor comprising the hydraulic device according to any one of claims 1 to 9.

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