JP2023147426A - Hydraulic pressure rotating machine - Google Patents

Abstract

To secure the favorable slide performance of a rotor and a slide face, and to reduce manufacturing costs of the rotor and a valve plate.SOLUTION: A rotor 7 has a recessed curved face part 7c abutting on a valve plate 15 so as to be slidable, the valve plate 15 has a protruded curved face part 15A on which the recessed curved face part 7C of the rotor 7 abuts so as to be slidable, a cross section of the recessed curve face part 7C of the rotor 7 is formed of a homogeneous circular arc radius SRr, and a cross section of the protruded curved face part 15A of the valve plate 15 is formed of a homogeneous circular arc radius SRp. Also, a circular arc center of at least either of a circular arc center of the cross section of the recessed curved face part 7C and a circular arc center of the cross section of the protruded curve face part 15A is moved in a radial direction of a rotating shaft 4, and at least either of the recessed curve face part 7C of the rotor 7 and the protruded curved face part 15A of the valve plate 15 is formed of a curved face which is obtained by rotating a circular arc which is moved with the rotating shaft 4 as a center.SELECTED DRAWING: Figure 2

Description

The present disclosure relates to a hydraulic rotary machine that is installed as a hydraulic motor or a hydraulic pump in a construction machine such as a hydraulic excavator.

Hydraulic excavators, which are a typical example of construction machinery, are equipped with a self-propelled lower traveling body and an upper rotating body mounted on the lower traveling body so as to be able to rotate. A hydraulic motor is usually used for a turning device that turns the body. A hydraulic motor consists of a rotary shaft that is rotatably provided in a casing, a rotor that is formed with multiple cylinders and cylinder ports and rotates together with the rotary shaft, and a rotor that is inserted into the multiple cylinders of the rotor so that it can reciprocate. It includes a plurality of pistons and a valve plate in which a supply/discharge port is formed that communicates intermittently with a plurality of cylinder ports as the rotor rotates.

When the pressure oil discharged from the hydraulic pump is supplied to the hydraulic motor, the pressure oil is sucked into multiple cylinders of the rotor through the supply/discharge port of the valve plate and the cylinder port of the rotor, and is inserted into these multiple cylinders. A plurality of pistons extend toward the swash plate. A shoe attached to the tip of the piston slides on the sliding surface of the swash plate in an annular trajectory, thereby rotating the rotor and rotating a rotating shaft spline-coupled to the rotor.

Since the rotor and the valve plate slide against each other when the rotating shaft rotates, the rotor is formed with a concave curved surface portion having a concave arc cross section (concave arc surface shape), and the valve plate is formed with a concave curved surface portion having a concave cross section. A convex curved surface portion having an arc shape (convex arc surface shape) is formed. In this way, the concave curved surface of the spherical rotor and the convex curved surface of the valve plate slide, so that when the rotor is tilted due to deflection of the rotating shaft, the center of rotation of the rotor is aligned along the curved surface. Self-aligning ability towards the center of the rotating shaft is exhibited. This ensures sealing between the cylinder port of the rotor on which high pressure is applied and the supply/discharge port of the valve plate.

By the way, when the concave curved surface of the rotor slides against the convex curved surface of the valve plate, the circumferential speed on the outer circumferential side of the rotor is higher than on the inner circumferential side. Therefore, when the rotor rotates at high speed, the concave curved surface of the rotor and the convex curved surface of the valve plate come into contact with each other on the outer circumferential side, causing a problem that the sliding surfaces of both may seize.

On the other hand, there are structures in which the radius of the arc of the concave curved surface of the rotor (arc radius) is set larger than the arc radius of the convex curved surface of the valve plate, or the outer circumferential side of the concave curved surface of the rotor is formed as a tapered surface. A hydraulic rotating machine has been proposed (Patent Document 1). According to the hydraulic rotary machine disclosed in Patent Document 1, a gap is secured between the outer circumference of the concave curved surface of the rotor and the outer circumference of the convex curved surface of the valve plate, thereby preventing seizure on the outer circumferential sides of the two. It can be suppressed.

Patent No. 6276911

However, when the outer peripheral side of the concave curved surface of the rotor is formed as a tapered surface as in Patent Document 1, the structure of the concave curved surface becomes complicated, and a lot of time is required for lapping the concave curved surface. Therefore, there is a problem that the manufacturing cost of the rotor increases. Moreover, in the hydraulic rotating machine according to Patent Document 1, the arc radius of the concave curved surface portion of the rotor is set larger than the arc radius of the convex curved surface portion of the valve plate. Contact occurs at the innermost periphery of the convex curved surface. For this reason, there is a problem in that a gap is created between the cylinder port of the rotor and the supply/discharge port of the valve plate, and the sealing performance between the two is deteriorated.

Further, in the hydraulic rotating machine according to Patent Document 1, the arc radius of the concave curved surface portion of the rotor is different from the arc radius of the convex curved surface portion of the valve plate. For this reason, lapping (co-lapping) cannot be performed with the concave curved surface of the rotor and the convex curved surface of the valve plate in direct contact with each other via an abrasive. As a result, a large amount of time is required for break-in operation to ensure good sliding properties between the concave curved surface of the rotor and the convex curved surface of the valve plate, leading to the problem of increased manufacturing costs for the rotor and valve plate. be.

An object of the present invention is to provide a hydraulic rotating machine that can ensure good sliding properties on the sliding surfaces of the rotor and valve plates, and can reduce the manufacturing cost of the rotor and valve plates. It's about doing.

The present invention provides a rotating shaft rotatably provided in a casing, a rotor provided in the casing so as to rotate together with the rotating shaft and having a plurality of cylinders and cylinder ports formed therein, and A valve in which a plurality of pistons reciprocatably inserted into a plurality of cylinders and a supply/discharge port are formed in which the rotor is slidably abutted and the plurality of cylinder ports are intermittently communicated with each other by rotation of the rotor. a plate, the rotor has a concave curved surface portion that slidably abuts the valve plate, and the valve plate has a convex curved surface portion that the concave curved surface portion of the rotor slidably abuts. In a hydraulic rotating machine, at least one of the concave curved surface portion of the rotor and the convex curved surface portion of the valve plate has an arc having an arc center shifted in a radial direction of the rotation shaft. It is characterized by having a curved surface obtained by rotating around the center.

According to the present invention, it is possible to form sliding surfaces with high sealing properties that match the respective port positions of the rotor and the valve plate, and it is possible to ensure good sliding properties between the two over a long period of time. Furthermore, the structures of the rotor and valve plate can be simplified, and manufacturing costs can be reduced.

1 is a sectional view showing a swash plate type hydraulic motor as a hydraulic rotary machine according to a first embodiment of the present invention. FIG. 3 is a sectional view showing a rotor and a valve plate according to the first embodiment. FIG. 2 is a conceptual diagram conceptually showing a concave curved surface portion of a rotor and a convex curved surface portion of a valve plate according to the first embodiment. FIG. 4 is an enlarged view of a main part showing an enlarged view of section IV in FIG. 3; FIG. 6 is a conceptual diagram showing a state in which the concave curved surface portion of the rotor and the convex curved surface portion of the valve plate are in contact with each other. FIG. 7 is a sectional view showing a rotor and a valve plate according to a comparative example. FIG. 7 is a conceptual diagram conceptually showing a concave curved surface portion of a rotor and a convex curved surface portion of a valve plate according to a comparative example. FIG. 7 is a conceptual diagram showing a state in which a concave curved surface portion of a rotor and a convex curved surface portion of a valve plate are in contact with each other according to a comparative example. FIG. 7 is a sectional view showing a rotor and a valve plate according to a second embodiment. FIG. 7 is a conceptual diagram conceptually showing a concave curved surface portion of a rotor and a convex curved surface portion of a valve plate according to a second embodiment. FIG. 11 is an enlarged view of main parts showing an enlarged view of section XI in FIG. 10; FIG. 6 is a conceptual diagram showing a state in which the concave curved surface portion of the rotor and the convex curved surface portion of the valve plate are in contact with each other. FIG. 7 is a sectional view showing a rotor and a valve plate according to a third embodiment. FIG. 7 is a conceptual diagram conceptually showing a concave curved surface portion of a rotor and a convex curved surface portion of a valve plate according to a third embodiment. FIG. 6 is a conceptual diagram showing a state in which the concave curved surface portion of the rotor and the convex curved surface portion of the valve plate are in contact with each other.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a hydraulic rotary machine according to the present invention will be described in detail with reference to FIGS. 1 to 15, taking as an example a case in which it is applied to a variable displacement swash plate type hydraulic motor.

1 to 5 show a first embodiment of the invention. In FIG. 1, a variable displacement swash plate type hydraulic motor 1 (hereinafter referred to as hydraulic motor 1) is connected to a hydraulic pump (none of which is shown) via a hydraulic conduit, and is supplied with hydraulic oil (not shown) from the hydraulic pump. The rotating shaft 4 is rotated by pressure oil). The hydraulic motor 1 includes a casing 2, a rotating shaft 4, a rotor 7, a swash plate 12, a valve plate 15, etc., which will be described later.

The casing 2 constitutes the outer shell of the hydraulic motor 1. The casing 2 is formed into a bottomed cylindrical shape by a cylindrical portion 2A and a bottom portion 2B, and the open end side of the cylindrical portion 2A is closed by a lid 3. A shaft insertion hole 2C is formed in the bottom portion 2B. Inside the casing 2, a rotating shaft 4, a rotor 7, a swash plate 12, a valve plate 15, etc. are housed.

The rotating shaft 4 is provided within the cylindrical portion 2A of the casing 2, and is rotatable about the shaft center AA with respect to the casing 2. One axial end of the rotating shaft 4 is supported by the bottom 2B of the casing 2 via a bearing 5 installed in the shaft insertion hole 2C, and the other axial end of the rotating shaft 4 is supported via a bearing 6. It is supported by the lid body 3.

The rotor 7 is rotatably provided within the cylindrical portion 2A of the casing 2. The rotor 7 has a cylindrical shape, and a center hole 7A passing through the rotor 7 in the axial direction and a hole spline 7B are formed concentrically in the center of the rotor 7. A rotating shaft 4 is inserted through the center hole 7A of the rotor 7, and an intermediate portion of the rotating shaft 4 is splined to a hole spline 7B of the rotor 7. Thereby, the rotor 7 rotates together with the rotating shaft 4. The rotor 7 is formed with a plurality of cylinders 8 that are spaced apart in the circumferential direction and extend in the axial direction, and a plurality of cylinder ports 9 that communicate with each of the cylinders 8 and open into a concave curved surface portion 7C, which will be described later. ing.

A plurality of pistons 10 (only two are shown) are fitted into a plurality of cylinders 8 formed in the rotor 7 so as to be able to reciprocate, respectively. A disc-shaped shoe 11 is swingably attached to the tip (projecting end) of the piston 10 that projects from the cylinder 8 . The shoe 11 is pressed against the sliding surface 12A of the swash plate 12 by the piston 10, and thus slides on the sliding surface 12A in an annular trajectory as the rotor 7 rotates.

The swash plate 12 is located within the casing 2 between the bottom 2B of the casing 2 and the rotor 7. The swash plate 12 is formed into a disc shape surrounding the rotating shaft 4. The back side of the swash plate 12 facing the bottom 2B is rotatably supported by a swash plate support member 13 having a convex arc surface and projecting from the bottom 2B of the casing 2. On the other hand, the surface of the swash plate 12 that faces the rotor 7 becomes a flat sliding surface 12A, on which the shoe 11 attached to the tip of the piston 10 moves in an annular trajectory when the rotor 7 rotates. It slides as if drawing.

The tilt actuator 14 is provided between the bottom 2B of the casing 2 and the swash plate 12. The tilting actuator 14 includes a tilting cylinder 14A formed on the bottom portion 2B and a tilting piston 14B inserted into the tilting cylinder 14A. The tilting actuator 14 presses the swash plate 12 with the tilting piston 14B by supplying pressure oil (tilting control pressure) to the tilting cylinder 14A. Thereby, the swash plate 12 tilts with respect to the bottom part 2B using the swash plate support member 13 as a fulcrum, and changes the stroke amount of the piston 10 according to the tilt angle, thereby varying the rotation speed of the hydraulic motor 1. to control.

The valve plate 15 is located within the casing 2 between the lid body 3 and the rotor 7. The valve plate 15 is attached to the lid body 3 using a knock pin (not shown) or the like. The valve plate 15 has a pair of supply/discharge ports 16 that intermittently communicate with a plurality of cylinders 8 formed on the rotor 7 , and these pair of supply/discharge ports 16 communicate with a pair of supply/discharge ports 16 formed on the lid 3 . They each communicate with a drainage path (not shown). A convex curved surface portion 15A is formed on the end surface of the valve plate 15 facing the rotor 7.

Next, the shape of the concave curved surface portion 7C of the rotor 7 and the shape of the convex curved surface portion 15A of the valve plate 15 according to the first embodiment will be described with reference to FIGS. 2 to 5.

The concave curved surface portion 7C is provided on the end surface of the rotor 7 that faces the valve plate 15. A plurality of cylinder ports 9 formed in the rotor 7 are opened in this concave curved surface portion 7C. The concave curved surface portion 7C of the rotor 7 has an arc-shaped cross-sectional shape with a uniform arc radius SRr centered on a point B on the axial center AA of the rotating shaft 4, which is the rotation center of the rotor 7 (arc center). have. That is, the concave curved surface portion 7C of the rotor 7 is formed as a concave arc surface having an arc radius SRr with a point B on the shaft center AA as the arc center.

The convex curved surface portion 15A is provided on the end surface of the valve plate 15 that faces the rotor 7. The convex curved surface portion 15A is formed by, for example, welding a copper alloy to the surface of the valve plate 15, and the concave curved surface portion 7C of the rotor 7 slidably abuts on the convex curved surface portion 15A. The convex curved surface portion 15A of the valve plate 15 moves by a length σ in the radial direction of the rotary shaft 4 (direction perpendicular to the shaft center A-A) with respect to point B on the shaft center A-A of the rotary shaft 4. It has an arcuate cross-sectional shape having a uniform arc radius SRp with the arc center at point C. That is, one of the concave curved surface portion 7C of the rotor 7 and the convex curved surface portion 15A of the valve plate 15, the convex curved surface portion 15A, is an arc having an arc center shifted by a length σ in the radial direction of the rotating shaft 4. It has a curved surface obtained by rotating around the rotation axis 4. Specifically, the convex curved surface portion 15A has a circular arc centered on a point C, which is moved by a length σ in the radial direction of the rotating shaft 4 from a point B on the axis center AA. It is formed as a convex circular arc surface with a circular arc radius SRp having a curved surface obtained by rotating the surface. In this case, the circular arc radius SRr of the concave curved surface portion 7C and the circular arc radius SRp of the convex curved surface portion 15A have the relationship expressed by the following equation 1.

In this way, the concave curved surface portion 7C of the rotor 7 is formed as a concave arc surface with the arc center at the point B on the axis AA and the radius SRr, and the convex curved surface portion 15A of the valve plate 15 is formed as a concave arc surface with the arc center at the point B on the axis It is formed as a convex circular arc surface with a circular arc radius SRp whose center is a point C which is shifted from B by a length σ in the radial direction of the rotating shaft 4.

Here, a method of calculating the amount of movement σ of the arc center C of the convex curved surface portion 15A from the axis center AA of the rotating shaft 4 will be explained.

FIG. 3 conceptually shows the shapes of the concave curved surface portion 7C of the rotor 7 and the convex curved surface portion 15A of the valve plate 15. A state in which they are arranged at intervals on the center AA is shown. In FIG. 3, the concave curved surface portion 7C of the rotor 7 is formed as a concave arc surface having an arc radius SRr with a point B on the shaft center AA of the rotating shaft 4 as the arc center. Further, the convex curved surface portion 15A' of the virtual valve plate shown by the two-dot chain line in FIG. 3 is formed as a convex circular arc surface with the circular arc center at the point B and the circular arc radius SRp. The arc radius SRr of the concave curved surface portion 7C is set larger than the arc radius SRp of the convex curved surface portion 15A' (SRr>SRp).

Here, the center of the cylinder port 9 opened in the concave curved surface portion 7C is designated as D, the straight line connecting points B and D is designated as E, and the intersection of the straight line E and the convex curved surface portion 15A' is designated as F. As shown in an enlarged view in FIG. 4, an interval of SRr-SRp is formed in the radial direction between the point D and the intersection F, and an interval of length σ is formed in the radial direction of the rotating shaft 4. ing. Therefore, by moving the intersection point F between the straight line E and the convex curved surface portion 15A' by the length σ in the radial direction of the rotating shaft 4, the convex curved surface portion 15A' can be moved to the position of the center D of the cylinder port 9. It can be brought into contact with the concave curved surface portion 7C. In this case, assuming that the angle between the straight line E and the axis center AA is θ, the movement amount σ is calculated by the following equation 2.

In this way, the convex curved surface portion 15A is formed into an arc whose center is at a point C that is shifted by a length σ in the radial direction of the rotating shaft 4 from point B, which is the arc center of the virtual convex curved surface portion 15A'. It is formed as a convex arc surface with a radius SRp, and the intersection F between the convex curved surface portion 15A and the straight line E abuts the concave curved surface portion 7C at the center D of the cylinder port 9. Therefore, by opening the supply/discharge port 16 formed in the valve plate 15 at the position of the intersection F, the cylinder of the concave curved surface 7C is in contact with the concave curved surface 7C and the convex curved surface 15A. The portion where the port 9 opens can be brought into contact with the portion of the convex curved surface portion 15A where the supply/discharge port 16 opens. As a result, as shown in FIG. 5, the concave curved surface portion 7C of the rotor 7 and the convex curved surface portion 15A of the valve plate 15 are connected to a portion of the concave curved surface portion 7C where a plurality of cylinder ports 9 open and a convex curved surface portion. 15A, it has an annular sliding region 19 that relatively rotates while in contact with the portion where the supply/discharge port 16 opens. As a result, the cylinder port 9 of the rotor 7 and the supply/discharge port 16 of the valve plate 15 can be aligned, and the configuration can ensure sealing between the cylinder port 9 and the supply/discharge port 16. ing.

The hydraulic motor 1 according to the first embodiment has the above-described configuration, and the pressure oil discharged from the hydraulic pump is transferred from the hydraulic conduit through the supply/discharge port 16 of the valve plate 15 and the cylinder port 9 of the rotor 7 to the cylinder. 8. As a result, the piston 10 inserted into the cylinder 8 extends from the rotor 7 toward the swash plate 12, and the shoe 11 provided at the tip of the piston 10 presses the swash plate 12 while sliding the swash plate 12. The surface 12A is slid in a circular trajectory. As a result, the rotor 7 rotates, the rotating shaft 4 spline-coupled to the rotor 7 rotates, and the torque of the rotating shaft 4 is increased by a reduction gear or the like, thereby driving the traveling device and swing device of the hydraulic excavator. be able to.

Here, in this embodiment, the arc radius SRr of the concave arc surface of the concave curved surface section 7C formed on the rotor 7 is larger than the arc radius SRp of the convex arc surface of the convex curve section 15A formed on the valve plate 15. It is set large (SRr>SRp). Furthermore, as shown in FIG. 2, the convex curved surface portion 15A is a curved surface obtained by rotating an arc having an arc center shifted by a length σ in the radial direction of the rotating shaft 4, i.e. , a curved surface (spherical surface) obtained by rotating an arc around the rotation axis 4, with a circular arc centered at a point C shifted in the radial direction of the rotation axis 4 by a length σ from the point B on the axis center A-A. It is formed as a convex circular arc surface with a circular arc radius SRp. As a result, as shown in FIG. 5, the concave curved surface portion 7C of the rotor 7 is in contact with the convex curved surface portion 15A of the valve plate 15, and the supply/discharge port 16 of the valve plate 15 and the cylinder port 9 of the rotor 7 are connected to each other. can be accurately aligned, and sealing performance between the supply/discharge port 16 and the cylinder port 9 can be ensured. As a result, when high-pressure oil discharged from the pump is supplied to the cylinder 8 of the rotor 7 through the supply and discharge port 16 and the cylinder port 9, the pressure oil leaks from between the supply and discharge port 16 and the cylinder port 9. can be suppressed.

On the other hand, since the arc radius SRr of the concave curved surface portion 7C of the rotor 7 is set larger than the arc radius SRp of the convex curved surface portion 15A of the valve plate 15, the outer circumference of the concave curved surface portion 7C of the rotor 7 and the valve plate An outer gap 17 can be secured between the outer peripheral part of the convex curved surface part 15A of 15. Moreover, an inner gap 18 can be secured between the inner circumferential portion of the concave curved surface portion 7C of the rotor 7 and the inner circumferential portion of the convex curved surface portion 15A of the valve plate 15 (see FIG. 5).

That is, the concave curved surface portion 7C of the rotor 7 and the convex curved surface portion 15A of the valve plate 15 are connected to a portion of the concave curved surface portion 7C where a plurality of cylinder ports 9 open, and a portion of the convex curved surface portion 15A to which the supply/discharge port 16 is opened. It has an annular sliding region 19 that contacts each other at the opening portion and rotates relative to each other with an inner gap 18 provided inside (inner circumferential side) (see FIG. 5). Therefore, even when the rotor 7 rotates at high speed, the concave curved surface 7C of the rotor 7 and the convex curved surface 15A of the valve plate 15 are prevented from coming into contact with each other on the outer and inner circumferential sides, and the concave curved surface 7C and the convex Burn-in with the mold curved surface portion 15A can be prevented.

Moreover, the concave curved surface portion 7C of the rotor 7 is formed as a concave arc surface with a uniform arc radius SRr, and the convex curve surface portion 15A of the valve plate 15 is also formed as a convex arc surface with a uniform arc radius SRp. There is. For this reason, compared to, for example, a structure in which the outer circumferential side of the rotor has a large circular arc radius or the outer circumferential side of the rotor has a tapered surface, the rotor 7 has a concave curved surface part 7C, and the valve has a convex curved surface part 15A. The structure of the plate 15 can be simplified. As a result, manufacturing costs for the rotor 7 and the valve plate 15 can be reduced.

Furthermore, the dimensional difference between the circular arc radius SRr of the concave curved surface portion 7C and the circular arc radius SRp of the convex curved surface portion 15A, and the circular arc center C of the convex curved surface portion 15A with respect to the point B on the axial center AA of the rotating shaft 4. By adjusting the movement amount σ, the outer gap 17 formed on the contact surface between the concave curved surface portion 7C and the convex curved surface portion 15A, and the outer periphery between the concave curved surface portion 7C and the convex curved surface portion 15A, and The inner gap 18 formed at the inner periphery of the concave curved surface portion 7C and the convex curved surface portion 15A can be set as appropriate. As a result, the degree of freedom when designing the concave curved surface portion 7C of the rotor 7 and the convex curved surface portion 15A of the valve plate 15 can be increased.

Next, the reason why the arc center C of the convex arc surface of the convex curved surface portion 15A of the valve plate 15 was moved by the length σ in the radial direction of the rotating shaft 4 will be explained in comparison with the comparative example shown in FIGS. 6 to 8. Explain based on comparison.

FIG. 6 shows a rotor 101 and a valve plate 102 that are a comparative example of the rotor 7 and valve plate 15 according to the first embodiment. A plurality of cylinder ports 101B are opened in the concave curved surface 101A of the rotor 101, and a pair of supply/discharge ports 102B are opened in the convex curved surface 102A of the valve plate 102.

In FIG. 6, the concave curved surface portion 101A of the rotor 101 is formed as a concave arc surface having an arc radius SRr with the arc center at a point B on the axis AA. On the other hand, the convex curved surface portion 102A of the valve plate 102 is formed as a convex arc surface having an arc radius SRp with the arc center at point B on the axis AA. That is, the convex curved surface portion 102A of the valve plate 102 corresponds to the convex curved surface portion 15A' shown by the two-dot chain line in FIGS. 3 and 4. The arc radius SRr of the concave curved surface portion 101A is set larger than the arc radius SRp of the convex curved surface portion 102A (SRr>SRp).

FIG. 7 shows a state in which the concave curved surface portion 101A and the convex curved surface portion 102A face each other with a gap between them, and FIG. It shows. In the comparative example, the arc radius SRr of the concave curved surface portion 101A is set larger than the arc radius SRp of the convex curved surface portion 102A (SRr>SRp), and the arc center of the concave curved surface portion 101A and the convex curved surface portion 102A are The center of the arc is point B on the axis center AA.

Therefore, as shown in FIG. 8, when the rotor 101 rotates, the concave curved surface portion 101A and the convex curved surface portion 102A come into contact at the innermost circumferential portion, and are not in contact on the outer circumferential side, so that the outer gap 103 is formed. Therefore, when the rotor 101 rotates, it is possible to prevent seizure from occurring in the outer peripheral portion where the circumferential speed is high. However, when the concave curved surface portion 101A and the convex curved surface portion 102A are in contact with each other at the innermost circumferential portion, a minute gap 104 is also formed between the cylinder port 101B of the rotor 101 and the supply/discharge port 102B of the valve plate 102. be done. Therefore, when high pressure acts between the supply/discharge port 102B and the cylinder port 101B, there is a problem in that this pressure oil leaks.

In contrast, in the present embodiment, the convex curved surface portion 15A of the valve plate 15 is formed by rotating an arc having an arc center shifted by a length σ in the radial direction of the rotating shaft 4. It has a curved surface. The concave curved surface 7C of the rotor 7 and the convex curved surface 15A of the valve plate 15 are arranged such that the concave curved surface 7C has a plurality of cylinder ports 9 open, and the convex curved surface 15A has the supply/discharge port 16. It has an annular sliding region 19 that rotates relative to the opening portion while being in contact with each other. As a result, the supply/discharge port 16 of the valve plate 15 and the cylinder port 9 of the rotor 7 are accurately aligned with the concave curved surface 7C of the rotor 7 in contact with the convex curved surface 15A of the valve plate 15. , it is possible to suppress the formation of a gap between the two. As a result, it is possible to ensure sealing between the supply/discharge port 16 and the cylinder port 9, and to prevent high-pressure oil from leaking between the supply/discharge port 16 and the cylinder port 9 when the hydraulic motor 1 is operated. It can be prevented.

Thus, the hydraulic motor 1 according to the first embodiment includes a rotating shaft 4 rotatably provided in the casing 2, and a plurality of cylinders 8 and cylinders provided in the casing 2 so as to rotate together with the rotating shaft 4. A rotor 7 in which a port 9 is formed, a plurality of pistons 10 that are reciprocatably inserted into a plurality of cylinders 8 of the rotor 7, and the rotor 7 slidably abut, and the plurality of cylinder ports are opened by the rotation of the rotor 7. The rotor 7 has a concave curved surface portion 7C that slidably abuts on the valve plate 15, and the valve plate 15 The concave curved surface 7C has a convex curved surface 15A in slidable contact, and at least one of the concave curved surface 7C of the rotor 7 and the convex curved surface 15A of the valve plate 15 extends in the radial direction of the rotating shaft 4. It has a curved surface obtained by rotating an arc with a shifted arc center C around the rotation axis 4.

According to this configuration, good sliding properties of the sliding surface between the concave curved surface portion 7C of the rotor 7 and the convex curved surface portion 15A of the valve plate 15 can be ensured. Moreover, compared to a structure in which, for example, the outer circumferential side of the rotor has a large circular arc radius or the outer circumferential side of the rotor has a tapered surface, the rotor 7 has a concave curved surface part 7C, and the valve plate has a convex curved surface part 15A. 15 structures can be simplified. As a result, manufacturing costs for the rotor 7 and the valve plate 15 can be reduced.

In the embodiment, the concave curved surface portion 7C of the rotor 7 and the convex curved surface portion 15A of the valve plate 15 are arranged at a portion of the concave curved surface portion 7C where a plurality of cylinder ports 9 open, and a portion of the convex curved surface portion 15A where the cylinder ports 9 are opened. It has an annular sliding region 19 that contacts each other at the opening portion of the port 16 and rotates relative to the other with an inner gap 18 provided inside the annular sliding region 19 . According to this configuration, with the concave curved surface 7C of the rotor 7 in contact with the convex curved surface 15A of the valve plate 15, the supply/discharge port 16 of the valve plate 15 and the cylinder port 9 of the rotor 7 are accurately connected. The positions can be aligned, and the sealing performance between the supply/discharge port 16 and the cylinder port 9 can be ensured.

In the embodiment, the concave curved surface portion 7C of the rotor 7 has a concave arc surface with a predetermined arc radius SRr in its cross section, and the convex curved surface portion 15A of the valve plate 15 has a concave surface of the concave curved surface portion 7C in its cross section. It has a convex circular arc surface with a circular arc radius SRp smaller than the circular arc radius SRp of the circular arc surface. According to this configuration, by making the arc radius SRp of the convex curved surface portion 15A of the valve plate 15 smaller than the arc radius SRr of the concave curved surface portion 7C of the rotor 7, the outer peripheral portion of the concave curved surface portion 7C and the convex curved surface An outer gap 17 can be secured between the outer peripheral part of the portion 15A, and an inner clearance 18 can be secured between the inner peripheral part of the concave curved part 7C and the inner peripheral part of the convex curved part 15A. As a result, it is possible to prevent seizure between the concave curved surface portion 7C and the convex curved surface portion 15A when the rotor 7 rotates.

Next, FIGS. 9 to 12 show a second embodiment of the present invention. The feature of this embodiment is that the arc center of the concave curved surface portion formed on the rotor is moved by a length σ in the radial direction of the rotating shaft 4. Note that in this embodiment, the same components as those in the first embodiment are given the same reference numerals, and their explanations will be omitted.

FIG. 9 shows a rotor 21 and a valve plate 22 according to a second embodiment. The convex curved surface portion 22A of the valve plate 22 has an arcuate cross-sectional shape with a uniform arc radius SRp centered on a point B on the axial center AA of the rotating shaft 4. That is, the convex curved surface portion 22A of the valve plate 22 is formed as a convex arc surface having an arc radius SRp with the arc center at point B on the axial center AA.

On the other hand, the concave curved surface portion 21A of the rotor 21 is shifted by a length σ in the radial direction of the rotary shaft 4 (direction perpendicular to the shaft center A-A) with respect to point B on the shaft center A-A of the rotary shaft 4. It has an arc-shaped cross-sectional shape with a uniform arc radius SRr with the arc center at point C. That is, the concave curved surface portion 21A of the rotor 21 has a circular arc centered on a point C that is shifted in the radial direction of the rotating shaft 4 by a length σ from a point B on the shaft center A-A. It is formed as a concave circular arc surface with a circular arc radius SRr and has a curved surface obtained by rotating. Further, the arc radius SRr of the concave curved surface portion 21A of the rotor 21 is set larger than the arc radius SRp of the convex curved surface portion 22A of the valve plate 22 (SRr>SRp).

Here, a method of calculating the amount of movement σ of the arc center C of the concave curved surface portion 21A from the axis center AA of the rotating shaft 4 will be explained.

FIG. 10 conceptually shows the shapes of the concave curved surface portion 21A of the rotor 21 and the convex curved surface portion 22A of the valve plate 22. A state in which they are arranged at intervals on the center AA is shown. In FIG. 10, the convex curved surface portion 22A of the valve plate 22 is formed as a convex arc surface having an arc radius SRp with the arc center at a point B on the shaft center AA of the rotating shaft 4. Further, the concave curved surface portion 21A' of the virtual rotor shown by the two-dot chain line in FIG. 10 is formed as a concave circular arc surface with the circular arc center at the point B and the circular arc radius SRr.

Let D be the center of the supply/discharge port 16 opened in the convex curved surface portion 22A, E be the straight line connecting points B and D, and F be the intersection of the straight line E and the concave curved surface portion 21A'. As shown in an enlarged view in FIG. 11, an interval of SRr-SRp is formed in the radial direction between the point D and the intersection F, and an interval of length σ is formed in the radial direction of the rotating shaft 4. ing. Therefore, by shifting the intersection point F between the straight line E and the concave curved surface portion 21A' by the length σ in the radial direction of the rotating shaft 4, the concave curved surface portion 21A' can be shaped into a convex shape at the center D of the supply/discharge port 16. It can be brought into contact with the curved surface portion 22A. In this case, assuming that the angle between the straight line E and the axis center AA is θ, the length σ is calculated by the above equation 2.

In this way, the concave curved surface portion 21A is formed into a concave arc with a radius SRr centered at a point C that is obtained by shifting the arc center B of the virtual concave curved surface portion 21A' by a length σ in the radial direction of the rotating shaft 4. The concave curved surface portion 21A contacts the convex curved surface portion 22A at the center D of the supply/discharge port 16. Therefore, by opening the cylinder port 9 formed in the rotor 21 at the position of the intersection F, the cylinder port 9 of the concave curved surface 21A is in contact with the concave curved surface 21A and the convex curved surface 22A. It is possible to bring the portion of the convex curved surface portion 22A into contact with the portion of the convex curved surface portion 22A where the supply/discharge port 16 opens. Thereby, as shown in FIG. 12, the configuration is such that the supply/discharge port 16 of the valve plate 22 and the cylinder port 9 of the rotor 21 can be aligned.

The hydraulic motor according to the second embodiment has the rotor 21 and the valve plate 22 as described above, and in the second embodiment as well, the concave curved surface portion 21A of the rotor 21 is The convex curved surface portion 22A of the valve plate 22 is also formed as a convex arc surface with a uniform arc radius SRp. For this reason, compared to, for example, a structure in which the outer circumferential side of the rotor has a large circular arc radius or the outer circumferential side of the rotor has a tapered surface, the rotor 21 has a concave curved surface portion 21A, and the valve has a convex curved surface portion 22A. The structure of the plate 22 can be simplified and the processing costs of the rotor 21 and the valve plate 22 can be reduced. Further, the arc radius SRp of the convex arc surface of the convex curved surface portion 22A of the valve plate 22 is set smaller than the arc radius SRr of the concave arc surface of the concave curved surface portion 21A of the rotor 21. As a result, as shown in FIG. 12, an outer gap 23 is secured between the outer periphery of the concave curved surface 21A of the rotor 21 and the outer periphery of the convex curved surface 22A of the valve plate 22, and the concave curved surface of the rotor 21 is An inner gap 24 can be secured between the inner circumferential portion of the valve plate 21A and the inner circumferential portion of the convex curved surface portion 22A of the valve plate 22.

In this way, the concave curved surface portion 21A of the rotor 21 and the convex curved surface portion 22A of the valve plate 22 are connected to a portion of the concave curved surface portion 21A where a plurality of cylinder ports 9 open, and a portion of the convex curved surface portion 22A for supply/discharge. It has an annular sliding region 25 that contacts with the portion where the port 16 opens and rotates relative to each other with an inner gap 24 on the inside (inner circumferential side) (see FIG. 12). . Therefore, even when the rotor 21 rotates at high speed, contact between the concave curved surface 21A of the rotor 21 and the convex curved surface 22A of the valve plate 22 on the outer and inner circumferential sides can be suppressed, and the concave curved surface It is possible to prevent burning between the convex curved surface portion 21A and the convex curved surface portion 22A.

Furthermore, in the second embodiment, the arc center C of the convex arc surface of the convex curved surface portion 22A is shifted by a length σ in the radial direction of the rotating shaft 4. As a result, similarly to the first embodiment, the concave curved surface portion 21A of the rotor 21 is in contact with the convex curved surface portion 22A of the valve plate 22, and the supply/discharge port 16 of the valve plate 22 and the cylinder of the rotor 7 are connected. The port 9 can be accurately positioned, and the sealing performance between the supply/discharge port 16 and the cylinder port 9 can be ensured.

Next, FIGS. 13 to 15 show a third embodiment of the present invention. The feature of this embodiment is that the arc radius of the concave curved surface portion of the rotor and the arc radius of the convex curved surface portion of the valve plate are set equal, and the concave curved surface portion of the rotor and the convex curved surface portion of the valve plate are rotated. The shafts are configured so that they contact each other in the central region of the shaft and rotate relative to each other with a gap left in the outer peripheral region. Note that in this embodiment, the same components as those in the first embodiment are given the same reference numerals, and their explanations will be omitted.

FIG. 13 shows a rotor 31 and a valve plate 32 according to a third embodiment. The concave curved surface portion 31A of the rotor 31 has an arc-shaped cross-sectional shape with a uniform arc radius SRr centered on a point B on the axial center AA of the rotating shaft 4. That is, the concave curved surface portion 31A of the rotor 31 is formed as a concave arc surface having an arc radius SRr with the arc center at point B on the axis AA.

On the other hand, the convex curved surface portion 32A of the valve plate 32 has a circular arc centered at a point C which is shifted by a length σ in the radial direction of the rotary shaft 4 with respect to a point B on the shaft center AA of the rotary shaft 4. It has an arcuate cross-sectional shape with a circular arc radius SRp. That is, the convex curved surface portion 32A of the valve plate 32 has a circular arc centered on a point C that is shifted by a length σ in the radial direction of the rotating shaft 4 from a point B on the shaft center AA. It is formed as a convex circular arc surface with a circular arc radius SRp having a curved surface obtained by rotating the surface. Here, in this embodiment, the circular arc radius SRr of the concave curved surface portion 31A of the rotor 31 and the circular arc radius SRp of the convex curved surface portion 32A of the valve plate 32 have a relationship expressed by the following equation 3.

Here, the arc center C of the convex curved surface portion 32A of the valve plate 32 is shifted by a length σ in the radial direction of the rotary shaft 4 from a point B on the axis center AA of the rotary shaft 4. The movement amount σ of the arc center C is, for example, when the concave curved surface portion 31A of the rotor 31 is brought into contact with the convex curved surface portion 32A of the valve plate 32, and the outermost peripheral portion of the concave curved surface portion 31A and the convex curved surface portion 32A are It is set geometrically depending on how much outer gap 33 is required (necessary gap amount) between the outermost peripheral part of As a result, the concave curved surface portion 31A of the rotor 31 and the convex curved surface portion 32A of the valve plate 32 come into contact with each other in the central region of the rotating shaft 4, and rotate relative to each other with an outer gap 33 in the outer peripheral region. It is configured.

The hydraulic motor according to the third embodiment has the rotor 31 and the valve plate 32 as described above. The arc radius SRp of the convex arc surface of the convex curved surface portion 32A is set to be equal to the arc radius SRp (SRr=SRp). Further, the arc center C of the convex arc surface of the convex curved surface portion 32A is shifted by a length σ in the radial direction of the rotary shaft 4 from a point B on the axis center AA of the rotary shaft 4. As a result, as shown in FIG. 15, the concave curved surface portion 31A of the rotor 31 and the convex curved surface portion 32A of the valve plate 32 are in contact with each other at the innermost periphery, which is the central region of the rotating shaft 4, and the outer periphery An outer gap 33 is formed at the outermost periphery of the concave curved surface portion 31A and the convex curved surface portion 32A.

As described above, in the third embodiment, even when the arc radius SRr of the concave curved surface section 31A and the arc radius SRp of the convex curved surface section 32A are set equal (SRr=SRp), the arc radius SRr of the concave curved surface section 31A Similarly to the case where the arc radius SRp of the convex curved surface section 32A is set larger (SRr>SRp), the outer gap 33 can be secured at the outermost periphery between the concave curved surface section 31A and the convex curved surface section 32A. . Thereby, in this embodiment as well, it is possible to prevent the concave curved surface portion 31A and the convex curved surface portion 32A from sticking together.

Moreover, in the third embodiment, since the arc radius SRr of the concave curved surface portion 31A of the rotor 31 and the arc radius SRp of the convex curved surface portion 32A of the valve plate 32 are equal, the concave curved surface portion 31A and the convex curved surface portion 32A are Lapping processing (co-lapping) can be performed in a state in which the two are brought into direct contact via an abrasive. For this reason, when the arc radius of the concave curved surface of the rotor is different from the arc radius of the convex curved surface of the valve plate, it is difficult to compare the lapping process to the concave curved surface and the convex curved surface separately. Therefore, the time and cost required for processing can be reduced. Furthermore, after the concave curved surface portion 31A and the convex curved surface portion 32A are subjected to the lapping process, it is possible to eliminate the need for a long break-in operation in which the concave curved surface portion 31A and the convex curved surface portion 32A are brought into contact with each other. . As a result, manufacturing costs of the rotor 31 including the concave curved surface portion 31A and the valve plate 32 including the convex curved surface portion 32A can be reduced.

Thus, in the third embodiment, the arc radius SRr of the cross section of the concave curved surface portion 31A of the rotor 31 and the arc radius SRp of the cross section of the convex curved surface portion 32A of the valve plate 32 are set equal to each other, and the concave curved surface portion 31A The convex curved surface portions 32A are in contact with each other on the inner peripheral side, which is the central region of the rotating shaft 4, and rotate relative to each other with an outer gap 33 in the outer peripheral region. According to this configuration, since the outer gap 33 is secured at the outermost periphery between the concave curved surface portion 31A and the convex curved surface portion 32A, it is possible to prevent seizure between the concave curved surface portion 31A and the convex curved surface portion 32A. . Furthermore, lapping (co-lapping) can be performed with the concave curved surface portion 31A and the convex curved surface portion 32A in direct contact with each other via an abrasive, so that the concave curved surface portion 31A and the convex curved surface portion 32A can be The time and cost required for processing can be reduced.

Note that in the first embodiment, a case is illustrated in which the arc center C of the convex curved surface portion 15A of the valve plate 15 is moved by a length σ in the radial direction of the rotating shaft 4, and in the second embodiment, A case is illustrated in which the arc center C of the concave curved surface portion 21A of the rotor 21 is moved by a length σ in the radial direction of the rotating shaft 4. However, the present invention is not limited to this. For example, the center of the arc of the convex curved surface of the valve plate is moved by the length σp in the radial direction of the rotating shaft 4, and the center of the arc of the concave curved surface of the rotor is moved along the rotation axis. 4 by a length σr in the radial direction, so that the sum of the movement amount σp of the arc center of these convex curved surface portions and the movement amount σr of the arc center of the concave curved surface portion becomes the movement amount σ (σ = σp + σr). It may be configured as follows.

Further, in the embodiment, a variable displacement swash plate type hydraulic motor 1 is illustrated as the hydraulic rotating machine. However, the present invention is not limited to this, and can be widely applied to various hydraulic rotating machines equipped with a rotor and a valve plate, such as a variable displacement swash plate hydraulic pump, a tilt shaft hydraulic motor, and a tilt shaft hydraulic pump. be able to.

2 Casing 4 Rotating shaft 7, 21, 31 Rotor 7C, 21A, 31A Concave curved part 8 Cylinder 9 Cylinder port 10 Piston 15, 22, 32 Valve plate 15A, 22A, 32A Convex curved part 16 Supply/discharge port 17, 23, 33 Outside gap (gap)
18, 24 Inner gap (gap)
19,25 Sliding area

Claims (4)

A rotating shaft rotatably provided in a casing, a rotor provided in the casing and having a plurality of cylinders and cylinder ports formed therein so as to rotate together with the rotating shaft, and the plurality of cylinders of the rotor. The valve plate includes a plurality of pistons inserted and fitted in a reciprocating manner, and a valve plate formed with an supply/discharge port in which the rotor is slidably abutted and the plurality of cylinder ports are intermittently communicated with each other as the rotor rotates. ,
The rotor has a concave curved surface that slidably abuts on the valve plate, and the valve plate has a convex curved surface that the concave curved surface of the rotor slidably abuts. On the machine,
At least one of the concave curved surface portion of the rotor and the convex curved surface portion of the valve plate is obtained by rotating an arc having an arc center shifted in a radial direction of the rotation shaft around the rotation shaft. A hydraulic rotating machine characterized by having a curved surface. The concave curved surface portion of the rotor and the convex curved surface portion of the valve plate include a portion of the concave curved portion where the plurality of cylinder ports are open, and a portion of the convex curved portion where the supply/discharge port is open. 2. The hydraulic rotary machine according to claim 1, further comprising an annular sliding area that contacts each other at a portion where the sliding portion is rotated and rotates relative to each other with a gap between the annular sliding areas. The concave curved surface portion of the rotor has a concave arc surface with a predetermined arc radius in its cross section, and the convex curved surface portion of the valve plate has a concave arc surface with a predetermined arc radius in its cross section. The hydraulic rotating machine according to claim 2, characterized in that it has a convex arcuate surface with a radius. The circular arc radius of the cross section of the concave curved surface portion of the rotor and the circular arc radius of the cross section of the convex curved surface portion of the valve plate are set to be equal to each other,
The concave curved surface portion of the rotor and the convex curved surface portion of the valve plate are configured to contact each other in a central region of the rotating shaft and rotate relative to each other with a gap in an outer peripheral region. The hydraulic rotating machine according to claim 1, characterized in that:

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