阅读说明：本技术 液压装置 (Hydraulic device ) 是由 赤见俊也 山口祥 于 2019-08-30 设计创作，主要内容包括：本发明提供一种液压装置。液压装置具有：活塞；斜板,其与所述活塞相对地配置；以及斜板支承构件,其以使所述斜板的倾斜可变的方式支承该斜板。与压力油导入路径连通的储油部设置于所述斜板与所述斜板支承构件之间。所述斜板与所述斜板支承构件之间的所述储油部的面积根据所述斜板的倾斜而变化。(The invention provides a hydraulic device. The hydraulic device comprises: a piston; a swash plate disposed opposite to the pistons; and a swash plate support member that supports the swash plate so as to vary the inclination of the swash plate. An oil reservoir communicating with the pressure oil introduction path is provided between the swash plate and the swash plate support member. The area of the oil reservoir between the swash plate and the swash plate support member changes according to the inclination of the swash plate.)

1. A hydraulic device, wherein,

the hydraulic device is provided with:

a piston;

a swash plate disposed opposite to the pistons; and

a swash plate support member that supports the swash plate so as to vary the inclination of the swash plate,

an oil reservoir communicating with the pressure oil introduction path is provided between the swash plate and the swash plate support member,

the area of the oil reservoir between the swash plate and the swash plate support member changes according to the inclination of the swash plate.

2. The hydraulic apparatus of claim 1,

a1 st recess is formed in a surface of the swash plate facing the swash plate support member, the 1 st recess forming the oil reservoir,

a2 nd recessed portion is formed on a surface of the swash plate support member facing the swash plate, the 2 nd recessed portion forming the oil reservoir,

the area of the region where the 1 st recess and the 2 nd recess overlap varies according to the inclination of the swash plate.

3. The hydraulic apparatus of claim 1,

the area of the oil reservoir in a maximum inclination state in which the inclination angle of the swash plate with respect to a vertical plane perpendicular to the direction of motion of the pistons is maximum is larger than the area of the oil reservoir in an intermediate state between the minimum inclination state in which the inclination angle is minimum and the maximum inclination state.

4. The hydraulic apparatus of claim 1,

the area of the oil reservoir in a minimum inclination state in which the inclination angle of the swash plate with respect to a vertical plane perpendicular to the direction of motion of the pistons is minimum is larger than the area of the oil reservoir in an intermediate state between the maximum inclination state in which the inclination angle is maximum and the minimum inclination state.

5. The hydraulic apparatus of claim 1,

the swash plate support member has a pair of support portions arranged separately,

the swash plate has a pair of supported portions supported by the pair of support portions of the swash plate support member,

the oil reservoir is formed between one supporting portion and one supported portion,

the oil reservoir is formed between the other support portion and the other supported portion.

6. The hydraulic apparatus of claim 5,

the area of the oil reservoir formed between the one supporting portion and the one supported portion is smaller than the area of the oil reservoir formed between the other supporting portion and the other supported portion.

7. The hydraulic apparatus of claim 1,

a1 st recess is formed in a surface of the swash plate facing the swash plate support member, the 1 st recess forming the oil reservoir,

a2 nd recessed portion is formed on a surface of the swash plate support member facing the swash plate, the 2 nd recessed portion forming the oil reservoir,

the 1 st and 2 nd recesses are separated from each other according to inclination of the swash plate.

8. A hydraulic device, wherein,

the hydraulic device is provided with:

a piston;

a swash plate disposed opposite to the pistons; and

and a swash plate support member that supports the swash plate so as to vary the inclination of the swash plate, wherein the swash plate support member is provided with a2 nd recess, and the area of a region where the 2 nd recess overlaps with a1 st recess provided in the swash plate varies according to the inclination of the swash plate.

Technical Field

The present invention relates to a hydraulic device having a swash plate.

Background

For example, as disclosed in patent document 1(JP2016-133074a), a swash plate type hydraulic device is known. In the hydraulic device disclosed in patent document 1, a swash plate is disposed so as to face the pistons in the operating direction of the pistons, and limits the operating range of the pistons. The swash plate is supported by the swash plate support member so that the inclination (orientation) thereof is variable, i.e., deflectable. In this hydraulic device, the stroke of the piston can be changed by deflecting the swash plate, and the output from the hydraulic device can be adjusted.

As disclosed in patent document 1, in such a hydraulic device, the swash plate is pressed toward the swash plate support member by the piston due to the working fluid (oil) in the cylinder chamber housing the piston. When the swash plate is pressed against the swash plate support member at a high pressure, the force required for the swash plate tilting operation increases, and the swash plate cannot be tilted smoothly. In patent document 1, in order to smooth the operation of the swash plate in response to such a problem, an oil reservoir is provided between the swash plate and the swash plate support member. The swash plate can be pressed to a side away from the swash plate support member by supplying the working fluid to the oil reservoir. In addition, in patent document 1, the swash plate is easily tilted in one direction by changing the size of the side wall of the oil reservoir.

However, the force required to deflect the swash plate is not constant, and varies depending on the inclination of the swash plate. At the start of, for example, the swash plate deflection, the swash plate held at a predetermined relative position with respect to the swash plate support member must be operated with a large force exceeding a static friction force that is significantly larger than a dynamic friction force. Further, the force that the swash plate receives from the yaw adjustment mechanism that adjusts the inclination of the swash plate also depends on the structure of the yaw adjustment mechanism, and generally, this force varies depending on the inclination of the swash plate. Typically, when the swash plate is maintained in the upright state with a reduced inclination angle, the swash plate is pressed against the swash plate support member with a stronger force by the yaw adjustment mechanism. When the force with which the swash plate is pressed against the swash plate support member increases, the force required to deflect the swash plate also increases.

On the other hand, in the hydraulic apparatus disclosed in patent document 1, the force received by the swash plate from the oil reservoir is constant regardless of the inclination of the swash plate. If the force with which the oil reservoir presses the swash plate is set low in consideration of the fact that the force required to deflect the swash plate is low, the swash plate cannot be deflected smoothly when the swash plate stands up, for example, at the start of the above-described deflection of the swash plate. In this case, a hysteresis phenomenon occurs in the horsepower characteristic, and the performance of the hydraulic device is degraded. On the other hand, if the force with which the oil reservoir presses the swash plate is set high in view of the fact that the force required to deflect the swash plate is high, when the swash plate can be sufficiently deflected with a small force, the oil in the oil reservoir leaks out from between the swash plate and the swash plate support member, and the performance of the hydraulic device is still degraded.

Disclosure of Invention

The present invention has been made in view of the above points, and an object thereof is to effectively suppress a performance degradation of a hydraulic device associated with a swash plate deflecting operation.

The hydraulic device of the present invention includes: a piston;

a swash plate disposed opposite to the pistons; and

a swash plate support member that supports the swash plate so as to vary the inclination of the swash plate,

an oil reservoir communicating with the pressure oil introduction path is provided between the swash plate and the swash plate support member,

the area of the oil reservoir between the swash plate and the swash plate support member changes according to the inclination of the swash plate.

In the hydraulic apparatus according to the present invention, a1 st concave portion may be formed on a surface of the swash plate facing the swash plate support member, the 1 st concave portion forming the oil reservoir,

a2 nd recessed portion is formed on a surface of the swash plate support member facing the swash plate, the 2 nd recessed portion forming the oil reservoir,

the area of the region where the 1 st recess and the 2 nd recess overlap varies according to the inclination of the swash plate.

In the hydraulic apparatus according to the present invention, an area of the oil reservoir in a maximum inclination state in which an inclination angle of the swash plate with respect to a vertical plane perpendicular to the operating direction of the pistons is maximum may be larger than an area of the oil reservoir in an intermediate state between the minimum inclination state and the maximum inclination state in which the inclination angle is minimum.

In the hydraulic apparatus according to the present invention, an area of the oil reservoir in a minimum inclination state in which an inclination angle of the swash plate with respect to a vertical plane perpendicular to the operating direction of the pistons is minimum may be larger than an area of the oil reservoir in an intermediate state between the maximum inclination state and the minimum inclination state in which the inclination angle is maximum.

In the hydraulic apparatus according to the present invention, an area of the oil reservoir in an intermediate state between a minimum inclination state in which an inclination angle of the swash plate with respect to a vertical plane perpendicular to an operation direction of the pistons is minimum and a maximum inclination state in which the inclination angle is maximum may be smaller than at least one of the area of the oil reservoir in the minimum inclination state and the area of the oil reservoir in the maximum inclination state.

In the hydraulic apparatus according to the present invention, an area of the oil reservoir in an intermediate state between a minimum inclination state in which an inclination angle of the swash plate with respect to a vertical plane perpendicular to an operation direction of the pistons is minimum and a maximum inclination state in which the inclination angle is maximum may be smaller than both the area of the oil reservoir in the minimum inclination state and the area of the oil reservoir in the maximum inclination state.

In the hydraulic apparatus of the present invention, it is also possible,

the swash plate support member has a pair of support portions arranged separately,

the swash plate has a pair of supported portions supported by the pair of support portions of the swash plate support member,

the oil reservoir is formed between one supporting portion and one supported portion,

the oil reservoir is formed between the other support portion and the other supported portion.

In the hydraulic apparatus according to the present invention, an area of the oil reservoir formed between the one support portion and the one supported portion may be smaller than an area of the oil reservoir formed between the other support portion and the other supported portion.

In the hydraulic apparatus of the present invention, it is also possible,

a1 st recess is formed in a surface of the swash plate facing the swash plate support member, the 1 st recess forming the oil reservoir,

a2 nd recessed portion is formed on a surface of the swash plate support member facing the swash plate, the 2 nd recessed portion forming the oil reservoir,

the 1 st and 2 nd recesses are separated from each other according to inclination of the swash plate.

The 2 nd hydraulic device of the present invention includes:

a piston;

a swash plate disposed opposite to the pistons; and

and a swash plate support member that supports the swash plate so as to vary the inclination of the swash plate, wherein the swash plate support member is provided with a2 nd recess, and the area of a region where the 2 nd recess overlaps with a1 st recess provided in the swash plate varies according to the inclination of the swash plate.

According to the present invention, it is possible to effectively suppress a decrease in performance of the hydraulic device associated with the swash plate deflecting operation.

Drawings

Fig. 1 is a diagram for explaining an embodiment of the present invention, and is a vertical cross-sectional view showing an example of a hydraulic apparatus.

Fig. 2 is an exploded perspective view showing a swash plate and a swash plate support member which can be applied to the hydraulic apparatus of fig. 1.

Fig. 3 is an exploded perspective view illustrating the swash plate and the swash plate support member of fig. 2 from different directions.

Fig. 4 is a view for explaining example 1 of the oil reservoir formed between the swash plate and the swash plate support member.

Fig. 5 is a view for explaining example 2 of the oil reservoir formed between the swash plate and the swash plate support member.

Fig. 6 is a diagram for explaining example 3 of the oil reservoir formed between the swash plate and the swash plate support member.

Fig. 7 is a diagram for explaining example 4 of the oil reservoir formed between the swash plate and the swash plate support member.

Fig. 8 is a view for explaining example 5 of the oil reservoir formed between the swash plate and the swash plate support member.

Fig. 9 is a view for explaining example 6 of the oil reservoir formed between the swash plate and the swash plate support member.

Fig. 10 is a view for explaining example 7 of the oil reservoir formed between the swash plate and the swash plate support member.

Detailed Description

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. For ease of understanding, elements shown in the drawings may include elements whose dimensions, scales, and the like are different from actual dimensions, scales, and the like.

The hydraulic device 10 described below is a so-called variable displacement swash plate type piston pump/motor, and can be used as two actuators, i.e., a pump and a motor. In the case where the hydraulic apparatus 10 is flexibly used as a hydraulic pump, the hydraulic apparatus 10 sucks the working oil into the cylinder chamber 21, which will be described later, and discharges the working oil from the cylinder chamber 21. On the other hand, in the case of flexibly employing the hydraulic device 10 as a hydraulic motor, the hydraulic device 10 outputs rotation of the rotary shaft member 18, which will be discussed later. More specifically, when the hydraulic device 10 according to the embodiment described below is used as a pump, the rotary shaft member 18 is rotated by power from a power source such as an engine, the cylinder block 20 coupled to the rotary shaft member 18 by spline coupling or the like is rotated, and the piston 25 is reciprocated by the rotation of the cylinder block 20. By this reciprocating operation of the piston 25, the hydraulic oil is sucked into some of the cylinder chambers 21, and the hydraulic oil is discharged from the other cylinder chambers 21, thereby realizing a hydraulic pump. On the other hand, when the hydraulic device 10 is used as a motor, the hydraulic oil is caused to flow into the cylinder chamber 21 by the power from the power source and is discharged from the other cylinder chamber 21, so that the pistons are caused to slide and rotate on the swash plate while reciprocating the pistons. Since the cylinder 20 and the rotary shaft member 18 are also rotated in accordance with the operation of the piston 25, a hydraulic motor can be realized by utilizing the rotation of the rotary shaft member 18. Typically, the hydraulic device 10 can be used as a hydraulic circuit or a drive device provided in a construction machine, and can be applied to other applications, and the application is not particularly limited.

The hydraulic device 10 illustrated as a swash plate type includes: the housing 15, the rotary shaft member 18, the cylinder block 20, the pistons 25, the valve plate 30, the yaw adjusting mechanism 35, and the swash plate 50 constitute main components. Hereinafter, each constituent element will be described.

As shown in fig. 1, the housing 15 has a1 st housing block 15a and a2 nd housing block 15b fixed to the 1 st housing block 15 a. The 1 st housing block 15a and the 2 nd housing block 15b are fixed to each other using fasteners such as bolts. The housing 15 has a housing space S formed therein. The cylinder block 20, the piston 25, the valve plate 30, the yaw adjustment mechanism 35, and the swash plate 50 are disposed in the housing space S.

In the illustrated example, the valve plate 30 is disposed inside the 1 st housing block 15 a. The 1 st housing block 15a has a1 st flow path 11 and a2 nd flow path 12 communicating with the cylinder chamber 21 of the cylinder block 20 via the valve plate 30. In the drawings, for convenience of explanation, the 1 st flow path 11 and the 2 nd flow path 12 are indicated by lines, and actually have appropriate inner diameters corresponding to supply and discharge of the hydraulic oil to and from the cylinder chambers 21 of the cylinder block 20. The 1 st flow path 11 and the 2 nd flow path 12 are provided so as to penetrate the casing 15 from the inside of the casing 15 to the outside of the casing 15. The 1 st flow path 11 and the 2 nd flow path 12 communicate with an actuator, a hydraulic pressure source, and the like provided to the outside of the hydraulic device 10.

The rotary shaft member 18 is rotatably supported by the housing 15 via bearings 19a and 19 b. The rotary shaft member 18 is rotatable about its central axis line as a rotation axis RA. One end of the rotation shaft member 18 is rotatably supported by the 1 st housing block 15a via a bearing 19 b. The other end of the rotation shaft member 18 is rotatably supported by the 2 nd housing block 15b via a bearing 19a, and extends outside the housing 15 through a through hole provided in the 2 nd housing block 15 b. In the portion of the rotary shaft member 18 penetrating the housing 15, a seal member is provided between the housing 15 and the rotary shaft member 18 to prevent the working oil from flowing out of the housing 15. A portion of the rotary shaft member 18 extending from the housing 15 is connected to an input member such as a motor or an engine.

The cylinder 20 has a cylindrical or cylindrical shape disposed around the rotation axis RA. The cylinder 20 is penetrated by the rotary shaft member 18. The cylinder block 20 is coupled to the rotary shaft member 18 by spline coupling, for example. Therefore, the cylinder block 20 can rotate about the rotation axis RA in synchronization with the rotary shaft member 18.

The cylinder block 20 has a plurality of cylinder chambers 21 formed therein. The plurality of cylinder chambers 21 are arranged at equal intervals in the circumferential direction around the rotation axis RA. Each cylinder chamber 21 extends in an axial direction da parallel to the rotation axis RA and opens on the swash plate 50 side. Further, a connection port 22 is formed corresponding to each cylinder chamber 21. The connection port 22 opens the cylinder chamber 21 to the valve plate 30 side in the axial direction da.

A piston 25 is provided corresponding to each cylinder chamber 21. A part of each piston 25 is disposed in the cylinder chamber 21. Each piston 25 extends in the axial direction da from the corresponding cylinder chamber 21 toward the swash plate 50. The piston 25 is movable in an axial direction da relative to the cylinder 20. That is, the piston 25 can advance toward the swash plate 50 side in the axial direction da to increase the volume of the cylinder chamber 21. The piston 25 can retract toward the valve plate 30 in the axial direction da to reduce the volume of the cylinder chamber 21.

The swash plate 50 is supported in the housing 15. The swash plate 50 is disposed to face the cylinder block 20 and the piston 25 in the axial direction da. In fig. 2 and 3, the swash plate 50 is illustrated together with a swash plate support member 70 that supports the swash plate 50. The rotary shaft member 18 penetrates through the central through hole 51 of the swash plate 50. The swash plate 50 has a main surface 52 (see fig. 2) at a position facing the cylinder block 20 and the piston 25. The main surface 52 can be inclined with respect to a plane perpendicular to the rotation axis RA, and the swash plate 50 is supported in the housing 15. The structure for holding the swash plate 50 is discussed later.

As shown in fig. 1, the shoe 26 is provided on the main surface 52 of the swash plate 50. The shoe 26 holds the head of the piston 25. Specifically, a head portion serving as one end of the piston 25 is formed in a spherical shape. The shoe 26 has a hole capable of receiving substantially half of the spherical head. The shoe 26 holding the head of the piston 25 is slidable on the main surface 52 of the swash plate 50.

The hydraulic device 10 further includes a holding plate 27 disposed in the housing 15, and the holding plate 27 is an annular plate-shaped member. The holding plate 27 is penetrated by the rotary shaft member 18 and supported by the rotary shaft member 18. The support portion 18a of the rotary shaft member 18 that supports the holding plate 27 is formed in a curved surface shape. Therefore, the holding plate 27 can be changed in orientation in a state of being supported by the rotary shaft member 18. As shown in fig. 1, the plate-like holding plate 27 is inclined along the main surface 52 of the swash plate 50 and contacts the shoe 26.

Further, a piston pressing member 28 formed of a spring or the like is provided between the rotary shaft member 18 and the holding plate 27. The holding plate 27 is pressed toward the swash plate 50 in the axial direction da by the piston pressing member 28. As a result, the holding plate 27 can press the shoe 26 and the piston 25 against the main surface 52 of the swash plate 50. The rotary shaft member 18 is pressed toward the valve plate 30 in the axial direction da by the piston pressing member 28 together with the cylinder block 20. As a result, the cylinder block 20 is pressed against the valve plate 30.

As described above, the valve plate 30 is fixed to the 1 st housing block 15 a. That is, the valve plate 30 is stationary while the cylinder block 20 rotates together with the rotary shaft member 18. The valve plate 30 has two or more ports, not shown. Each port communicates with the 1 st channel 11 or the 2 nd channel 12. The ports are formed, for example, along an arc centered on the rotation axis RA, and face the connection ports 22 corresponding to the respective cylinder chambers 21 in sequence as the cylinder block 20 rotates. As a result, the connection between the cylinder chambers 21 and the 1 st flow path 11 and the 2 nd flow path 12 is switched according to the rotation state of the cylinder block 20.

Here, the operation of the hydraulic apparatus 10 will be described. When the hydraulic device 10 functions as a hydraulic pump, the rotary shaft member 18 rotates about the rotation axis line RA due to a rotational driving force from an input member such as a motor or an engine, not shown. At this time, the piston 25 advances so as to protrude from the cylinder 20 or retreats into the cylinder 20 as the cylinder 20 rotates. The volume of the cylinder chamber 21 changes due to the advancing and retreating operations of the piston 25.

While the piston 25 is retreating from a position (top dead center) at which it extends out to the maximum extent with respect to the cylinder chamber 21 to a position (bottom dead center) at which it enters into the cylinder chamber 21 to the maximum extent, the capacity of the cylinder chamber 21 in which the piston 25 is housed decreases. During at least a part of the period, the cylinder chamber 21 in which the piston 25 being retracted is housed is connected to, for example, the 1 st flow path 11 via a port, not shown, of the valve plate 30, and the working oil is discharged from the cylinder chamber 21. The 1 st flow path 11 is connected to an external actuator or the like as a high-pressure side flow path.

On the other hand, while the piston 25 advances from the bottom dead center to the top dead center, the capacity of the cylinder chamber 21 in which the piston 25 is housed increases. During at least a part of the period, the cylinder chamber 21 housing the advancing piston 25 is connected to, for example, the 2 nd flow path 12 via a port, not shown, of the valve plate 30, and the working oil is sucked into the cylinder chamber 21. The 2 nd flow path 12 is connected as a low-pressure side flow path to a tank or the like for storing hydraulic oil.

When the hydraulic apparatus 10 functions as a hydraulic motor, hydraulic oil is supplied from an external pump, not shown, into the cylinder chamber 21 of the hydraulic apparatus 10 through, for example, the 1 st flow path 11 and the valve plate 30. The piston 25 in the cylinder chamber 21 to which the working oil is supplied can advance so as to extend from the cylinder block 20. Therefore, the port, not shown, of the valve plate 30 connects the cylinder chamber 21 located on the path from the bottom dead center to the top dead center to the 1 st flow path 11 on the high pressure side. This enables the cylinder block 20 to be rotated by the hydraulic oil supplied from the external pump, and the rotational force to be output via the rotary shaft member 18.

The port, not shown, of the valve plate 30 connects the cylinder chamber 21 located on the path from the top dead center to the bottom dead center to the 2 nd flow path 12 on the low pressure side. Therefore, the hydraulic oil in the cylinder chamber 21 accommodating the piston 25 can be discharged to the 2 nd flow path 12 while the piston 25 is retreating from the top dead center to the bottom dead center. The hydraulic oil discharged from the hydraulic device 10 is collected by a tank or the like connected to the 2 nd flow path 12.

In the hydraulic apparatus 10 described above, the main surface 52 of the swash plate 50 regulates the amount of protrusion of the piston 25 from the cylinder block 20. Therefore, the stroke of the reciprocating motion of the piston 25 in the axial direction da is determined depending on the inclination of the swash plate 50, more precisely, the magnitude of the inclination angle θ i (see fig. 1) of the main surface 52 of the swash plate 50 with respect to the plane perpendicular to the axial direction da. Further, by changing the inclination of the swash plate 50, that is, by deflecting the swash plate 50, the output of the hydraulic device 10 can be changed. Specifically, when the inclination of the swash plate 50 is increased, in other words, when the inclination angle θ i is increased, the output of the hydraulic device 10 is increased. When the inclination of the swash plate 50 is small, in other words, the inclination angle θ i is small, the output of the hydraulic device 10 decreases. If the main surface 52 of the swash plate 50 is perpendicular to the axial direction da, that is, if the inclination angle θ i becomes 0 °, theoretically, no output can be obtained from the hydraulic device 10.

Therefore, in the illustrated hydraulic device 10, the swash plate 50 is held so as to be able to deflect. Hereinafter, a structure for holding the swash plate 50 in the housing 15 so as to be able to deflect will be described.

As shown in fig. 1, the hydraulic device 10 includes a swash plate support member 70 that supports the swash plate 50 so as to be able to change the inclination of the swash plate 50, that is, a swash plate support member 70 that supports the swash plate 50 so as to be able to deflect. As shown in fig. 2, the swash plate support member 70 has a base portion 72 fixed to the housing 15 and a support portion 73 provided on the base portion 72. The base portion 72 is formed with a central through hole 71 through which the rotary shaft member 18 passes. Base portion 72 is provided with a1 st support portion 73A and a2 nd support portion 73B so as to sandwich center through hole 71. The rotation shaft member 18 passes between the two support portions 73A, 73B. Each support portion 73 is formed with a housing recess 74 that houses the bulging portion 54, discussed later, of the swash plate 50. The housing recess 74 has a shape corresponding to a part of a cylinder (for example, a semi-cylinder). In the illustrated example, the swash plate support member 70 is formed separately from the housing 15 and is fixed to the housing 15 by a fixing member or the like. However, the swash plate support member 70 is not limited to this example, and may be formed integrally with the 2 nd housing block 15b as a part of the housing 15, for example, as a part of the 2 nd housing block 15 b.

On the other hand, as shown in fig. 1, the swash plate 50 has a supported portion 53 disposed on the support portion 73 of the swash plate support member 70. As shown in fig. 3, the supported portion 53 includes a bulging portion 54, and the bulging portion 54 has a shape complementary to the receiving recess 74. The bulge portion 54 has a shape corresponding to a part of a cylinder (for example, a semi-cylinder). The swash plate 50 includes a1 st supported portion 53A and a2 nd supported portion 53B which are arranged to be separated in the depth direction of the paper surface of fig. 1. The rotation shaft member 18 passes between the two supported portions 53A, 53B. As shown in fig. 2 and 3, the 1 st supported portion 53A is supported by the 1 st supporting portion 73A, and the 2 nd supported portion 53B is supported by the 2 nd supporting portion 73B.

In this example, the support portion 73 of the swash plate support member 70 has a support surface 75 along an arc in the housing recess 74. On the other hand, the supported portion 53 of the swash plate 50 has a sliding surface 55 along an arc. When the supported portion 53 is disposed in the housing recess 74 of the support portion 73, the sliding surface 55 of the supported portion 53 is in contact with the support surface 75 of the support portion 73, particularly in surface contact on a curved surface. The swash plate 50 including the supported portion 53 rotates relative to the swash plate support member 70 about the center of the arc defined by the sliding surface 55 and the support surface 75 as the yaw axis IA (see fig. 1) because the supported portion 53 slides relative to the support portion 73 in the housing recess 74. The center axis IA of the yawing operation is not particularly limited, but may be located on the main surface 52 of the swash plate 50. With this configuration, the swash plate 50 is supported by the swash plate support member 70 so that the inclination of the main surface 52 can be changed.

As shown in fig. 1, the hydraulic device 10 further includes a yaw adjustment mechanism 35 for controlling the inclination of the main surface 52 of the swash plate 50. In the illustrated example, the yaw adjusting mechanism 35 includes a swash plate pressing member 36 and a swash plate control device 37. The yaw adjustment mechanism 35 will be explained below.

The swash plate 50 shown in fig. 2 has a central portion 50a, a1 st force receiving portion 50b, and a2 nd force receiving portion 50 c. The central portion 50a is disposed between the 1 st force receiving portion 50b and the 2 nd force receiving portion 50 c. The central portion 50a is provided with the central through hole 51, the main surface 52, and the bulging portion 54. The 1 st force receiving portion 50b and the 2 nd force receiving portion 50c are portions extending from the central portion 50a to opposite sides, respectively.

The swash plate pressing member 36 and the swash plate controller 37 of the yaw adjustment mechanism 35 press the swash plate 50 so that the swash plate 50 deflects in opposite directions to each other. The swash plate 50 is held at a certain swash position by balancing the force pressed by the swash plate pressing member 36 and the force pressed by the swash plate control device 37. In the illustrated example, the swash plate pressing member 36 contacts the 1 st force receiving portion 50b of the swash plate 50 to press the swash plate 50 to be biased counterclockwise in fig. 1. The swash plate control device 37 contacts the 2 nd force receiving portion 50c of the swash plate 50 to press the swash plate 50 to deflect clockwise in fig. 1.

The swash plate pressing member 36 is supported by the 1 st housing block 15a of the housing 15. The swash plate pressing member 36 is formed of, for example, a compression spring. Thus, the swash plate pressing member 36 presses the swash plate 50 with an elastic force corresponding to the deformation force thereof.

On the other hand, the swash plate control device 37 is configured to adjust an actuator 38 and has a control piston 39. The control piston 39 can approach (advance) and retreat away (retreat) from the swash plate 50 in the axial direction da. The control piston 39 presses the 2 nd force receiving portion 50c of the swash plate 50. The control piston 39 is driven, for example, hydraulically. Further, the force with which the control piston 39 presses the 2 nd force receiving portion 50c can be adjusted. That is, the inclination angle θ i of the swash plate 50 can be controlled by adjusting the force output from the swash plate control device 37. Here, the inclination angle θ i is an inclination angle of the swash plate 50 with respect to a plane perpendicular to the axial direction da, which is the operation direction of the piston 25, that is, an angle formed by the main surface 52 of the swash plate 50 and a perpendicular plane perpendicular to the axial direction da (see fig. 1).

In the illustrated example, when there is no output from the swash plate control device 37, the inclination angle θ i is the maximum, and the swash plate 50 shown in fig. 1 is in the maximum inclination state. The control piston 39 of the swash plate control device 37 presses the 2 nd force receiving portion 50c of the swash plate 50, so that the swash plate 50 can be raised from the maximum inclination state to reduce the inclination angle θ i. Further, by pressing the swash plate 50 with a greater force by the swash plate control device 37, the swash plate 50 is raised so that the inclination angle θ i becomes 0 ° or a minimum angle close to 0 °.

In the illustrated typical example, the swash plate 50 is capable of being tilted from the maximum inclination state shown in fig. 1 to the standing state, and is not intended to be tilted to the opposite side of the state shown in fig. 1 beyond the standing state. Therefore, in the illustrated typical example, the standing state at the inclination angle of 0 ° is the minimum inclination state. In such an example, when the pressure in the cylinder chamber 21 passes through a region of the main surface 52 of the swash plate 50 where one supported portion 53 (in the example shown, the 1 st supported portion 53A) overlaps in the axial direction da, the pressure in the cylinder chamber 21 becomes high, and when the pressure in the main surface 52 of the swash plate 50 passes through a region of the other supported portion 53 (in the example shown, the 2 nd supported portion 53B) overlaps in the axial direction da, the pressure in the cylinder chamber 21 becomes low.

Here, during the operation of the hydraulic apparatus 10, the swash plate 50 is pressed toward the swash plate support member 70 by the pressure of the hydraulic oil in the cylinder chamber 21 in which the piston 25 is accommodated. In the illustrated example, the 1 st supported portion 53A on the high pressure side is pressed against the 1 st supporting portion 73A with a relatively strong force, and the 2 nd supported portion 53B on the low pressure side is pressed against the 2 nd supporting portion 73B with a relatively weak force. Further, when the swash plate 50 is pressed against the swash plate support member 70 at a high pressure, a force required for the swash plate 50 to deflect is also increased, and the swash plate 50 cannot be deflected smoothly.

On the other hand, as shown in fig. 2 and 3, an oil reservoir C is formed between the swash plate 50 and the swash plate support member 70. The oil reservoir C communicates with the pressure oil introduction path P. Here, the pressure oil introduction path P is a flow path of the pressurized hydraulic oil. Therefore, the oil reservoir C is filled with the pressurized oil, i.e., the pressurized working oil. The pressure oil in the oil reservoir C presses the swash plate 50 in the direction of the axial direction da away from the swash plate support member 70, in other words, in the direction of the axial direction da toward the cylinder block 20 and the piston 25. Further, an oil film is formed between the sliding surface 55 and the support surface 75, and direct frictional contact between the support portion 73 and the supported portion 53 can be avoided. The effect obtained by supplying the pressure oil into the oil reservoir C can reduce friction between the swash plate 50 and the swash plate support member 70. This can smooth the swash plate 50 deflection by the deflection adjusting mechanism 35.

In the illustrated example, the hydraulic device 10 is provided with a1 st introduction path Pa and a2 nd introduction path Pb as a pressure oil introduction path P. The 1 st introduction path Pa includes: a swash plate through hole Pa1 (see fig. 2 and 3) that passes through the 1 st supported portion 53A and penetrates the swash plate 50; and piston through holes Pa2 (see fig. 1) that pass through the pistons 25. When the pistons 25 pass through the swash plate through-holes Pa1 as the cylinder block 20 rotates, the 1 st introduction path Pa communicates the oil reservoir C with the cylinder chamber 21 filled with the high-pressure hydraulic oil, and the swash plate through-holes Pa1 open to the main surface 52 of the swash plate 50. On the other hand, the 2 nd introduction path Pb (see fig. 2) is a flow path formed, for example, in the casing 15 and the swash plate support member 70, and communicates the oil reservoir C with the 1 st flow path 11 on the high pressure side. The 1 st introduction path Pa communicates with a1 st recessed portion 60, which will be discussed later, of the oil reservoir C, for example. The 2 nd introduction path Pb communicates with a2 nd recess 80, such as an oil reservoir C, discussed later. Although not shown, a passage may be formed between the 1 st recess 60 and the 2 nd recess 80 to communicate the 1 st recess 60 with the 2 nd recess 80.

However, as already described in the column of the prior art, the force required to deflect the swash plate 50 is not constant, but varies depending on the inclination of the swash plate. On the other hand, when the force of the pressure oil in the oil reservoir C pressing the swash plate 50 in the direction away from the swash plate support member 70 is constant, the performance of the hydraulic device is degraded. Specifically, if the force with which the swash plate 50 is pressed by the pressure oil in the oil reservoir C is set to be low, when a large force is required for the swash plate 50 to deflect, a hysteresis occurs in the horsepower characteristics of the hydraulic device 10, and the performance of the hydraulic device is degraded. Conversely, if the force with which the swash plate 50 is pressed by the pressure oil in the oil reservoir C is set high, the oil in the oil reservoir C leaks from between the swash plate 50 and the swash plate support member 70 when the swash plate 50 can be deflected sufficiently with a small force, and the performance of the hydraulic device is degraded.

Therefore, in order to eliminate such a problem, the hydraulic apparatus 10 according to the present embodiment is studied to effectively suppress a performance degradation of the hydraulic apparatus 10 caused by the swash plate 50 deflecting operation. Specifically, the area of the oil reservoir C between the swash plate 50 and the swash plate support member 70 changes according to the inclination of the swash plate 50, that is, according to the inclination angle θ i. Here, the area of the oil reservoir C is an opening area of the oil reservoir C on a surface of the swash plate 50 along the surface where the supported portion 53 contacts the support portion 73 of the swash plate support member 70. The opening area of the oil reservoir C in the illustrated example is an area obtained by projecting the oil reservoir C onto a curved surface that extends along the sliding surface 55 of the supported portion 53 and the support surface 75 of the support portion 73 (along an arc, for example).

In the hydraulic device 10, by increasing the area of the oil reservoir C, the force with which the swash plate 50 is pressed in the axial direction da away from the swash plate support member 70 by the pressure oil in the oil reservoir C is also increased. Accordingly, an oil film is easily formed between the sliding surface 55 of the swash plate 50 and the support surface 75 of the swash plate support member 70. Conversely, by reducing the area of the oil reservoir C, the force with which the swash plate 50 is pressed in the axial direction da away from the swash plate support member 70 by the pressure oil in the oil reservoir C is also reduced. Accordingly, a large amount of pressure oil can be effectively prevented from leaking from between the sliding surface 55 of the swash plate 50 and the support surface 75 of the swash plate support member 70. In such a hydraulic device 10, the area of the oil reservoir C is changed in accordance with a change in force required to deflect the swash plate 50, and performance degradation of the hydraulic device 10 due to the deflecting operation of the swash plate 50 can be effectively suppressed.

In the illustrated example, as shown in fig. 2 and 3, an oil reservoir C having a variable area is provided between the 1 st supported portion 53A of the swash plate 50 pressed by the piston 25 at a high pressure and the 1 st supporting portion 73A of the swash plate supporting member 70 facing the 1 st supported portion 53A. That is, the oil reservoir C having a variable area is formed between the 1 st supported portion 53A and the 1 st supported portion 73A on the high pressure side.

In this example, as shown in fig. 3, the 1 st recess 60 is formed in the sliding surface 55 of the swash plate 50 facing the swash plate support member 70. The 1 st recess 60 has a bottom surface expanding along the sliding surface 55. However, the bottom surface of the 1 st recessed portion 60 is not limited to the illustrated example, and may be a flat surface instead of a curved surface, may be a bent surface including a plurality of flat surfaces, or may include a curved surface and a flat surface. As shown in fig. 3, the swash plate through hole Pa1 of the 1 st introduction path Pa opens into the 1 st recess 60. Therefore, the 1 st introduction path Pa can supply the pressure oil into the 1 st concave portion 60. On the other hand, as shown in fig. 2, a2 nd recess 80 is formed in the support surface 75 of the swash plate support member 70 facing the swash plate 50, and the 2 nd recess 80 forms the oil reservoir C. The 2 nd recess 80 has a bottom surface expanding along the bearing surface 75. The 2 nd introduction path Pb opens in the 2 nd recess 80. Therefore, the 2 nd introduction path Pb can supply the pressure oil into the 2 nd recess 80. The 1 st recess 60 and the 2 nd recess 80 form an oil reservoir C between the 1 st supported portion 53A of the swash plate 50 and the 1 st supporting portion 73A of the swash plate supporting member 70.

The area of the 1 st recess 60 and the area of the 2 nd recess 80 are not dependent on the inclination of the swash plate 50, but are constant. On the other hand, the 1 st recess 60 is provided at a constant position on the sliding surface 55, and the 2 nd recess 80 is provided at a constant position on the support surface 75. Thus, the relative positions of the 1 st recess 60 and the 2 nd recess 80 change with the deflection of the swash plate 50. In the illustrated example, the area of the region Z where the 1 st recess 60 and the 2 nd recess 80 overlap varies depending on the inclination of the swash plate 50. The area of the oil reservoir C between the swash plate 50 and the swash plate support member 70 is obtained by subtracting the area of the region Z where the 1 st recess 60 and the 2 nd recess 80 overlap from the sum of the area (opening area) of the 1 st recess 60 and the area (opening area) of the 2 nd recess 80, and the areas of the 1 st recess 60, the 2 nd recess 80, and the region Z are the areas between the swash plate 50 and the swash plate support member 70. Therefore, as the region Z where the 1 st recess 60 and the 2 nd recess 80 overlap changes, the area of the oil reservoir C between the swash plate 50 and the swash plate support member 70 changes according to the inclination of the swash plate 50.

A plurality of specific examples of the oil reservoir C will be described below mainly with reference to fig. 4 to 10. Fig. 4 to 10 show changes in the relative position between the 1 st recess 60 and the 2 nd recess 80, the shape of the oil reservoir C, and the area of the oil reservoir C, in accordance with the inclination of the swash plate 50 and the swash plate support member 70. The relative position between the 1 st recess 60 and the 2 nd recess 80 and the shape of the oil reservoir C are shown with respect to the deflected state (a) as the maximum inclined state, the deflected state (C) as the minimum inclined state with the inclination angle θ i of 0 °, and the deflected state (b) as the state between the deflected state (a) and the deflected state (C) shown in fig. 1. The change from the deflected state (a) to the deflected state (C) is graphed to show the change in the area of the oil reservoir C. In fig. 4 to 10, the sliding surface 55 of the swash plate 50 and the support surface 75 of the swash plate support member 70 are shown as being spread out in a planar shape.

< example 1 >

First, a1 st example of the oil reservoir C will be described with reference to fig. 4. In the example shown in fig. 4, the 1 st recess 60 formed in the sliding surface 55 extends in an elongated manner in the relative movement direction dm between the swash plate 50 and the swash plate support member 70. The length of the 1 st recess 60 along the relative movement direction dm is significantly longer than the length of the 2 nd recess 80 along the relative movement direction dm. In the example shown in fig. 4, the 1 st concave portion 60 has a constant width in the direction orthogonal to the relative movement direction dm and does not change at each position along the relative movement direction dm. Similarly, the 2 nd concave portion 80 has a constant width in the direction orthogonal to the relative movement direction dm and does not change at each position along the relative movement direction dm.

In the deflected state (a) which is the maximum inclined state, the 1 st recess 60 overlaps with the 2 nd recess 80. However, the 1 st recess 60 and the 2 nd recess 80 only partially overlap. When the inclination angle θ i is reduced from the maximum inclination state (the yaw state (a)), the area of the overlapped region Z increases. In a state between the deflected state (a) and the deflected state (b), the 2 nd concave portion 80 overlaps with the 1 st concave portion 60 in the entire region thereof. Thereafter, in the deflected state (b) and the deflected state (c) which is the minimum inclination state, the 2 nd concave portion 80 also maintains a state of overlapping with the 1 st concave portion 60 in the entire region thereof.

As shown in fig. 4, as the region Z where the 1 st recess 60 and the 2 nd recess 80 overlap changes, the area of the oil reservoir C changes according to the inclination angle θ i. In example 1, the area of the oil reservoir C is maximized in the deflected state (a) in which the maximum inclination state is achieved. While the inclination angle θ i is decreased from the deflected state (a) to a state between the deflected state (a) and the deflected state (b), the area of the oil reservoir C gradually decreases. Thereafter, the area of the oil reservoir C is constant and does not change until the swing state (C) which is the minimum inclination state is reached, regardless of whether the inclination angle θ i is decreased.

As described above, in example 1, the area of the oil reservoir C in the maximum inclination state (the inclination state (a)) in which the inclination angle θ i of the swash plate 50 is maximum is larger than the area of the oil reservoir C in a certain intermediate state (for example, the inclination state (b)) between the minimum inclination state (the inclination state (C)) in which the inclination angle θ i is minimum and the maximum inclination state.

For example, at the start of the swash plate deflection, the swash plate 50 held at a predetermined relative position with respect to the swash plate support member 70 must be operated with a large force exceeding a static friction force significantly larger than a dynamic friction force. As described above, generally, when the swash plate starts to deflect, the control piston 39 of the swash plate control device 37 does not press the swash plate 50, and therefore the swash plate 50 is pressed by the swash plate pressing member 36 and maintained to be inclined at the maximum inclination angle. Therefore, when the swash plate 50 maintained at the maximum inclination angle is deflected at the start of the deflection of the swash plate, the swash plate 50 generally needs to be operated with a large force.

In this regard, in example 1, the area of the oil reservoir C in the maximum inclination state is larger than that in the intermediate state, rather than being the smallest. In particular, in example 1, the area of the oil reservoir C is maximized or substantially maximized in the maximum inclination state. Therefore, when the swash plate 50 is in the maximum inclination state, the swash plate 50 can be pressed by the pressure oil in the oil reservoir C in a direction away from the swash plate support member 70 with a strong force. That is, when the force required to deflect the swash plate 50 is increased, the force can be changed so that the force with which the swash plate 50 is pressed away from the swash plate support member 70 by the pressure oil in the oil reservoir C is increased. This can suppress occurrence of hysteresis in the characteristics of the hydraulic device 10 (for example, horsepower characteristics of the hydraulic pump), and can more effectively avoid a decrease in the performance of the hydraulic device 10.

In addition, as a specific example, in the case where the hydraulic device 10 is used as a hydraulic pump, the hydraulic device 10 normally performs the horsepower control when the pressure thereof changes. In the horsepower control, the discharge pressure and the discharge flow rate of the hydraulic device 10 are suppressed so as not to exceed the allowable torque of an input member such as an engine that rotationally drives the hydraulic device 10 as a hydraulic pump. That is, in the horsepower control, the swash plate 50 that is greatly inclined at the time of low pressure is deflected so that the inclination angle θ i becomes smaller. At this time, the swash plate 50 that is stationary with respect to the swash plate support member 70 must be deflected, and a large force that can overcome the static friction force must be applied to the swash plate 50. In this regard, according to example 1, the area of the oil reservoir C in the maximum inclination state is larger than the area of the oil reservoir C in the intermediate state, and the swash plate 50 can be pressed by the pressure oil of the oil reservoir C with a large force in a direction away from the swash plate support member 70. Therefore, the operation of the swash plate in the horsepower control can be made smooth, and the occurrence of a significant hysteresis in the horsepower characteristic can be effectively prevented. This enables the characteristics of the hydraulic device 10 to be improved by efficiently utilizing the output from the input member such as the engine.

In example 1, the area of the oil reservoir C in the intermediate state between the maximum inclination state and the minimum inclination state is smaller than the area of the oil reservoir C in the maximum inclination state. As described above, the force required to deflect the swash plate 50 maintained at the maximum inclination angle tends to increase. On the other hand, in the intermediate state, the force required to deflect the swash plate 50 tends to be small. In example 1, the area of the oil reservoir C in the intermediate state is reduced, typically, minimized. That is, when the force required to deflect the swash plate 50 is reduced, the force with which the swash plate 50 is pressed in the direction away from the swash plate support member 70 by the pressure oil in the oil reservoir C is reduced. This can suppress leakage of the pressure oil in the oil reservoir C from between the swash plate 50 and the swash plate support member 70, and can more effectively avoid a decrease in performance of the hydraulic device 10.

< 2 nd example >)

Next, example 2 of the oil reservoir C will be described with reference to fig. 5. In the example shown in fig. 5, the position of the 2 nd recessed portion 80 on the support surface 75 of the swash plate support member 70 is different from that in the above-described 1 st embodiment, but may be otherwise the same as that in the 1 st embodiment. Hereinafter, a description of a configuration that can be the same as that of example 1 will be omitted, and a description will be given mainly of a configuration different from example 1.

As shown in fig. 5, in the deflected state (c) which is the minimum inclined state, the 1 st concave portion 60 overlaps with the 2 nd concave portion 80. However, the 1 st recess 60 and the 2 nd recess 80 only partially overlap. When the inclination angle θ i is increased from the minimum inclination state (the yaw state (c)), the area of the overlapped region Z increases. In a state between the deflected state (c) and the deflected state (b), the 2 nd concave portion 80 overlaps with the 1 st concave portion 60 in the entire region thereof. Thereafter, in the deflected state (b) and the deflected state (a) which is the maximum inclined state, the 2 nd concave portion 80 also maintains a state of overlapping with the 1 st concave portion 60 in the entire region thereof.

As shown in fig. 5, in example 2, in the deflected state (C) in which the minimum inclination state is achieved, the area of the overlapped region Z is the minimum, and thus the area of the oil reservoir C is the maximum. While the inclination angle θ is increased from the deflected state (C) to a state between the deflected state (b) and the deflected state (a), the area of the oil reservoir C gradually decreases. Thereafter, the area of the oil reservoir C is constant and does not change until the swing state (a) in which the inclination angle θ i is the maximum inclination state is reached, regardless of whether the inclination angle θ i is increased or not.

As described above, in example 2, the area of the oil reservoir C in the minimum inclination state (the inclination state (C)) in which the inclination angle θ i of the swash plate 50 is minimum is larger than the area of the oil reservoir C in a certain intermediate state (for example, the inclination state (b)) between the maximum inclination state (the inclination state (a)) and the maximum inclination state (the inclination state (b)) in which the inclination angle θ i is maximum.

The force that the swash plate 50 receives from, for example, the yaw adjustment mechanism 35 that adjusts the inclination of the swash plate 50 varies depending on the structure of the yaw adjustment mechanism 35 according to the inclination of the swash plate 50. In many hydraulic apparatuses 10, the swash plate 50 is pressed by the swash plate control device 37 against the pressing force of the swash plate pressing member 36 in order to reduce the inclination angle θ i of the swash plate 50. The elastic force of the swash plate pressing member 36 is increased by shortening the swash plate pressing member 36. Thus, typically, the swash plate 50 maintained at the minimum inclination angle is pressed toward the swash plate support member 70 with a very large force by the yaw adjustment mechanism 35. Therefore, when the swash plate 50 maintained at the minimum inclination angle is deflected, it is usually necessary to operate the swash plate 50 with a large force.

In this regard, in example 2, the area of the oil reservoir C in the minimum inclination state is larger than that in the intermediate state, rather than being the minimum. In particular, in example 2, the area of the oil reservoir C is maximized or substantially maximized in the minimum inclination state. Therefore, when the swash plate 50 is in the minimum inclination state, the swash plate 50 is pressed by the pressure oil in the oil reservoir C toward a direction away from the swash plate support member 70 with a strong force. That is, when the force required to deflect the swash plate 50 is increased, the force required to press the swash plate 50 away from the swash plate support member 70 by the pressure oil in the oil reservoir C can be changed so as to increase. This can suppress occurrence of hysteresis in the characteristics (e.g., horsepower characteristics in the hydraulic pump) of the hydraulic device 10, and can more effectively avoid a decrease in the performance of the hydraulic device.

As a specific example, the hydraulic device 10 as a hydraulic pump performs negative flow rate control based on an external sensor that can detect that the amount of pressure oil returned to the tank increases without being supplied to an actuator or the like connected to the hydraulic circuit. In the negative flow rate control, when an increase in the flow rate is detected by an external sensor, the swash plate 50 is maintained in a minimum inclination state or a state in which the inclination angle is extremely small. The swash plate 50 is pressed against the swash plate support member by a strong force from the yaw adjustment mechanism 35, and a large force needs to be applied to the swash plate 50 in order to yaw the swash plate 50. In this regard, according to example 2, the area of the oil reservoir C in the minimum inclination state is larger than the area of the oil reservoir C in the intermediate state, and the swash plate 50 can be pressed by the pressure oil of the oil reservoir C with a large force in a direction away from the swash plate support member 70. Therefore, the operation of the swash plate 50 in the negative flow control can be made smooth, and the suction horsepower characteristic can be effectively prevented from exhibiting a significant hysteresis.

In example 2, the area of the oil reservoir C in the intermediate state between the maximum inclination state and the minimum inclination state is smaller than the area of the oil reservoir C in the minimum inclination state. As described above, the force required to deflect the swash plate 50 maintained at the minimum inclination angle tends to increase. On the other hand, in the intermediate state, the force required to deflect the swash plate 50 tends to be small. In example 2, the area of the oil reservoir C in the intermediate state is reduced, typically, minimized. That is, when the force required to deflect the swash plate 50 is reduced, the force with which the swash plate 50 is pressed in the direction away from the swash plate support member 70 by the pressure oil in the oil reservoir C is reduced. This can suppress leakage of the pressure oil in the oil reservoir C from between the swash plate 50 and the swash plate support member 70, and can more effectively avoid a decrease in performance of the hydraulic device 10.

< example 3 >

Next, example 3 of the oil reservoir C will be described with reference to fig. 6. In the example shown in fig. 6, a plurality of 2 nd recesses 80 are provided on the support surface 75 of the swash plate support member 70 so as to be spaced apart in the relative movement direction dm. Example 3 differs from examples 1 and 2 in this point, and can be otherwise the same as example 1 or 2. By providing the plurality of 2 nd recessed portions 80 arranged to be spaced apart from each other in this manner, the degree of freedom in the arrangement of the oil reservoir C formed by the 1 st recessed portion 60 and the 2 nd recessed portion 80 can be increased, and the plurality of oil reservoirs C can be arranged in a dispersed manner between the support portion 73 of the swash plate support member 70 and the supported portion 53 of the swash plate 50. In addition, the oil reservoir C may be disposed so as to press the swash plate 50 substantially along the axial direction da, and the swash plate can be smoothly deflected.

As shown in fig. 6, the 2 nd concave portion 80 includes one side 2 nd concave portion 80a and the other side 2 nd concave portion 80b that are separated in the relative movement direction dm. In the specific example shown in fig. 6, the first 2 nd concave portion 80a is configured similarly to the second 2 nd concave portion 80 of the above-described 1 st example, and the second 2 nd concave portion 80b is configured similarly to the second 2 nd concave portion 80 of the above-described 2 nd example.

Therefore, in the deflected state (a) which is the maximum inclined state, the 1 st concave portion 60 and the one 2 nd concave portion 80a are only partially overlapped. When the inclination angle θ i is decreased from the maximum inclination state (the yaw state (a)), the area of the region Za where the 1 st concave portion 60 overlaps the one 2 nd concave portion 80a is increased. In a state between the deflected state (a) and the deflected state (b), the one-side 2 nd concave portion 80a overlaps the 1 st concave portion 60 in the entire region thereof. Thereafter, in the deflected state (b) and the deflected state (c) which is the minimum inclination state, the one-side 2 nd concave portion 80a also remains in a state of overlapping with the 1 st concave portion 60 in the entire region thereof.

On the other hand, in the deflected state (c) which is the minimum inclined state, the 1 st recessed portion 60 and the other 2 nd recessed portion 80b are only partially overlapped. When the inclination angle θ i is increased from the minimum inclination state (the deflected state (c)), the area of the region Zb where the 1 st recessed portion 60 and the other 2 nd recessed portion 80b overlap becomes large. In a state between the deflected state (c) and the deflected state (b), the other-side 2 nd recess 80b overlaps the 1 st recess 60 in the entire region thereof. Thereafter, in the deflected state (b) and the deflected state (a) which is the maximum inclined state, the other-side 2 nd concave portion 80b also remains in a state of overlapping with the 1 st concave portion 60 in the entire region thereof.

As shown in fig. 6, as the region Z where the 1 st recess 60 and the 2 nd recess 80 overlap changes, the area of the oil reservoir C changes according to the inclination angle θ i. In example 3, the area of the oil reservoir C is maximized or maximized in the deflected state (a) in which the maximum inclination state is achieved. While the inclination angle θ i is decreased from the deflected state (a) to a state between the deflected state (a) and the deflected state (b), the area of the oil reservoir C gradually decreases. Thereafter, the area of the reservoir C is a minimum constant area and does not change until the state between the deflected state (b) and the deflected state (C) regardless of whether the inclination angle θ i is reduced. When the inclination angle θ i is further decreased, the area of the oil reservoir C gradually increases. In the deflected state (C) in which the minimum inclination state is achieved, the area of the oil reservoir C is maximized or maximized.

According to such an example, the two operational effects described in example 1 and the operational effect described in example 2 can be exhibited, and the performance degradation of the hydraulic device 10 can be more effectively avoided.

< example 4 >

Next, a 4 th example of the oil reservoir C will be described with reference to fig. 7. In the example shown in fig. 7, the 1 st recess 60 and the 2 nd recess 80 are separated from each other according to the inclination of the swash plate 50. Example 4 differs from examples 1 to 3 in that example 1 and 2 of recess 60 and recess 80 overlap at least partially between the minimum inclination state and the maximum inclination state, and can be otherwise the same as examples 1 to 3. According to example 4, the degree of freedom in the arrangement of the oil reservoir C formed by the 1 st recess 60 and the 2 nd recess 80 can be increased, and a plurality of oil reservoirs C can be arranged in a distributed manner between the support portion 73 of the swash plate support member 70 and the supported portion 53 of the swash plate 50. In addition, the oil reservoir C may be disposed so as to press the swash plate 50 substantially along the axial direction da, and the swash plate can be smoothly deflected. Further, the area of the oil reservoir C can be maintained at the maximum value or the maximum value even while the inclination angle θ i is changed by the predetermined angle.

As shown in fig. 7, the 2 nd recess 80 includes one side 2 nd recess 80a and the other side 2 nd recess 80b that are separated in the relative movement direction dm. The one-side 2 nd recessed portion 80a in the specific example shown in fig. 7 is configured similarly to the one-side 2 nd recessed portion 80a of the above-described 3 rd example, except for the arrangement position. The other-side 2 nd concave portion 80b in the specific example shown in fig. 7 is configured similarly to the other-side 2 nd concave portion 80b of the above-described 3 rd example, except for the arrangement position.

As shown in fig. 7, in the deflected state (a) which is the maximum inclined state, the one-side 2 nd concave portion 80a is deviated in the relative movement direction dm from the 1 st concave portion 60 without overlapping with the 1 st concave portion 60. On the other hand, in the deflected state (a), the other-side 2 nd recess 80b overlaps the 1 st recess 60 in the entire region thereof. When the inclination angle θ i becomes smaller from the maximum inclination state, the one side 2 nd concave portion 80a starts to overlap with the 1 st concave portion 60. When the inclination angle θ i is further decreased, the region Za where the 1 st concave portion 60 overlaps the one 2 nd concave portion 80a gradually increases. Between the deflected state (a) and the deflected state (b), the one-side 2 nd concave portion 80a overlaps the 1 st concave portion 60 in the entire region thereof. The one-side 2 nd recess 80a maintains a state of overlapping with the 1 st recess 60 in the entire region thereof during the period of subsequently decreasing the inclination angle θ i to the deflected state (c) which is the minimum inclined state.

On the other hand, the other-side 2 nd recess 80b is maintained in a state of overlapping with the 1 st recess 60 over the entire region thereof while decreasing the inclination angle θ i from the deflected state (a) to a state between the deflected state (b) and the deflected state (c). Therefore, in this period, the region Zb where the 1 st recess 60 overlaps the other 2 nd recess 80b is constant. As a result, the region Z where the 1 st concave portion 60 overlaps the 2 nd concave portion 80 is kept constant during a state where the inclination angle θ i is within a certain angle range including the deflected state (b).

When the inclination angle θ i is decreased, the other side 2 nd concave portion 80b overlaps the 1 st concave portion 60 only at a part thereof. If the inclination angle θ i is further decreased, the other-side 2 nd concave portion 80b is positioned offset from the 1 st concave portion 60 in the relative movement direction dm without overlapping the 1 st concave portion 60.

In the example shown in fig. 7, the area of the oil reservoir C is maintained at the maximum or maximum during a state in which the inclination angle θ i is within a certain angle range, including the yaw state (a) which is the maximum inclination state. When the inclination angle θ i is decreased, the area of the oil reservoir C is minimized or extremely small. Similarly, in the example shown in fig. 7, the area of the oil reservoir C is maintained at the maximum or maximum during a state in which the inclination angle θ i is within a certain angle range, including the yaw state (C) which is the minimum inclination state. When the inclination angle θ i is increased, the area of the oil reservoir C is minimized or extremely small. In the example shown in fig. 7, the area of the oil reservoir C is kept to a minimum or minimum while the inclination angle θ i is within a certain angle range including the deflected state (b).

That is, compared with the change in the area of the oil reservoir C in the above-described 3 rd example, the change in the area of the oil reservoir C in the 4 th example shown in fig. 7 is different in the following points: the area of the oil reservoir C is the largest or the largest and is maintained constant in the vicinity of the deflected state (a), and the area of the oil reservoir C is the largest or the largest and is maintained constant in the vicinity of the deflected state (C). According to example 4, the same operational effects as those of example 3 can be obtained.

< example 5 >

Next, a description will be given of example 5 of the oil reservoir C with reference to fig. 8. In the example shown in fig. 8, in addition to the 1 st recess 60, the 2 nd recess 80 is elongated in the relative movement direction dm between the swash plate 50 and the swash plate support member 70. Example 5 differs from examples 1 to 4 in this point, and can be otherwise the same as any of examples 1 to 4.

In the example shown in fig. 8, the 2 nd recess 80 is formed on the support surface 75 across the following area: the region where the one-side 2 nd recessed portion 80a and the other-side 2 nd recessed portion 80b in example 3 described above are arranged, and the region between the one-side 2 nd recessed portion 80a and the other-side 2 nd recessed portion 80b in example 3. The area of the oil reservoir C of example 5 shown in fig. 8 changes in accordance with the inclination of the swash plate 50 in the same manner as the area of the oil reservoir C of example 3 described above. Therefore, according to example 5, the same operational effects as those of example 3 can be obtained.

In example 5, the length of the 2 nd concave portion 80 along the relative movement direction dm is shorter than the length of the 1 st concave portion 60 along the relative movement direction dm, but the present invention is not limited to this example, and the length of the 2 nd concave portion 80 along the relative movement direction dm may be the same as the length of the 1 st concave portion 60 along the relative movement direction dm. In such a modification, the area of the oil reservoir C may be adjusted to change appropriately with the inclination of the swash plate 50, and may be changed in the same manner as the area of the oil reservoir C in example 3 described above.

< 6 th example >)

Next, example 6 of the oil reservoir C will be described with reference to fig. 9. In the example shown in fig. 9, the length of the 2 nd concave portion 80 along the relative movement direction dm is longer than the length of the 1 st concave portion 60 along the relative movement direction dm. Example 6 is different from examples 1 to 5 described above in this point, and can be otherwise the same as any of examples 1 to 5.

In the example shown in fig. 9, the 1 st recess 60 is configured in the same manner as the 2 nd recess 80 in the above-described 3 rd embodiment. Thus, the 1 st recess 60 has one side 1 st recess 60a and the other side 1 st recess 60 b. The 2 nd recessed portion 80 is configured similarly to the 1 st recessed portion 60 in example 3. Therefore, the area of the oil reservoir C of example 6 shown in fig. 9 changes in accordance with the inclination of the swash plate 50 in the same manner as the area of the oil reservoir C of example 3 described above. According to example 6, the same operational effects as those of example 3 can be obtained.

< example 7 >

Next, example 7 of the oil reservoir C will be described with reference to fig. 10. In example 7, the width along the direction orthogonal to the relative movement direction dm is not constant for at least one of the 1 st recess 60 and the 2 nd recess 80, but varies at each position along the relative movement direction dm. According to such an example, the rate of change of the region Z where the 1 st recess 60 and the 2 nd recess 80 overlap with the inclination of the swash plate 50 is not constant. As a result, as shown in fig. 10, the rate of change in the area of the oil reservoir C caused by the inclination of the swash plate 50 is not constant but can be adjusted.

In the example shown in fig. 10, the configuration of the 2 nd concave portion 80 is different from that of the above-described 1 st embodiment, and may be otherwise the same as that of the 1 st embodiment. Specifically, the 2 nd concave portion 80 of the 7 th example shown in fig. 10 is different in shape from the 2 nd concave portion 80 of the 1 st example. However, the present invention is not limited to this example, and the width of the 1 st concave portion 60 may be changed, or both the width of the 1 st concave portion 60 and the width of the 2 nd concave portion 80 may be changed.

In the above-described embodiment, the hydraulic apparatus 10 includes: a piston 25; a swash plate 50 disposed opposite to the pistons 25 in the operating direction of the pistons 25; and a swash plate support member 70 that supports the swash plate 50 so as to vary the inclination of the swash plate 50. An oil reservoir C communicating with the pressure oil introduction path P is formed between the swash plate 50 and the swash plate support member 70. The area of the oil reservoir C between the swash plate 50 and the swash plate support member 70 changes according to the inclination of the swash plate 50.

The force required to deflect the swash plate 50 is not constant, but varies depending on the inclination of the swash plate 50. Further, regardless of whether the force required to deflect the swash plate 50 is large, if the force with which the swash plate 50 is pressed in the direction away from the swash plate support member 70 by the pressure oil in the oil reservoir C is set to be small, the swash plate 50 cannot be deflected smoothly. At this time, hysteresis occurs in the characteristics of the hydraulic device (for example, horsepower characteristics of the hydraulic pump), and the performance of the hydraulic device is degraded. Conversely, even if the force required to deflect the swash plate 50 is small but sufficient, if the force with which the swash plate 50 is pressed away from the swash plate support member 70 by the pressure oil in the oil reservoir C is set to be large, the oil in the oil reservoir C leaks out from between the swash plate 50 and the swash plate support member 70, and the performance of the hydraulic device (for example, the volumetric efficiency of the hydraulic pump) is still degraded.

In view of such a problem, in the above-described embodiment, as the area of the oil reservoir C between the swash plate 50 and the swash plate support member 70 changes, the force with which the pressure oil stored in the oil reservoir C presses the swash plate 50 away from the swash plate support member 70 also changes according to the inclination of the swash plate 50. Therefore, when the force required to deflect the swash plate 50 is increased, the force with which the swash plate 50 is pressed away from the swash plate support member 70 by the pressure oil in the oil reservoir C is changed so as to increase the force, and therefore, hysteresis can be suppressed from occurring in the characteristics of the hydraulic device 10 (for example, the horsepower characteristics of the hydraulic pump), and a decrease in the performance of the hydraulic device 10 can be effectively avoided. When the force required to deflect the swash plate 50 is reduced, the force with which the swash plate 50 is pressed away from the swash plate support member 70 by the pressure oil in the oil reservoir C is changed so as to be reduced, and the pressure oil in the oil reservoir C can be effectively prevented from leaking between the swash plate 50 and the swash plate support member 70. This can effectively avoid a decrease in the performance of the hydraulic device 10 (e.g., a decrease in the volumetric efficiency of the hydraulic pump). As described above, according to the present embodiment, it is possible to effectively suppress performance degradation of the hydraulic device 10 that occurs due to the swash plate 50 deflecting operation.

In the above-described specific example, the 1 st recess 60 is formed in the surface 55 of the swash plate 50 facing the swash plate support member 70, the 1 st recess 60 forms the oil reservoir C, and the 2 nd recess is formed in the surface 75 of the swash plate support member 70 facing the swash plate 50, and the 2 nd recess forms the oil reservoir. The areas of the 1 st and 2 nd recesses 60, 80 forming the oil reservoir C are constant regardless of the inclination of the swash plate 50. On the other hand, the area of the region Z where the 1 st recess 60 and the 2 nd recess 80 overlap varies depending on the inclination of the swash plate 50. In this example, the area of the oil reservoir C, which is a value obtained by subtracting the area of the region Z where the 1 st recess 60 and the 2 nd recess 80 overlap from the sum of the area of the 1 st recess 60 and the area of the 2 nd recess 80, changes according to the inclination of the swash plate 50, and the areas of the 1 st recess 60, the 2 nd recess 80, and the region Z each refer to the area between the swash plate 50 and the swash plate support member 70. With the 1 st recess 60 and the 2 nd recess 80, the area of the oil reservoir C can be changed according to the inclination of the swash plate with a simple configuration.

While one embodiment has been described above with reference to a plurality of specific examples, it is not intended to limit the specific examples to one embodiment. The above-described embodiment can be implemented in various other specific examples, and various omissions, substitutions, and changes can be made without departing from the spirit thereof. An example of the modification is explained below.

The configuration, more specifically, the arrangement, shape, number, and the like of the 1 st recess 60 and the 2 nd recess 80 can be appropriately changed. For example, at least one of 1 st recess 60 and 2 nd recess 80 may have a circular, elliptical, triangular, polygonal, or the like planar shape. Further, the width of 1 st concave portion 60 may be wider than the width of 2 nd concave portion 80, or the width of 1 st concave portion 60 may be narrower than the width of 2 nd concave portion 80.

In the specific example of the hydraulic device 10 described above, the oil reservoir C having a variable area is provided between the 1 st supported portion 53A of the swash plate 50 pressed by the piston 25 at a high pressure and the 1 st supporting portion 73A of the swash plate supporting member 70 facing the 1 st supported portion 53A. That is, the oil reservoir C having a variable area is formed between the 1 st supported portion 53A and the 1 st supported portion 73A on the high pressure side. In addition to the oil reservoir C, as shown in fig. 3, a2 nd oil reservoir C2 may be formed between the 2 nd supported portion 53B and the 2 nd supporting portion 73B on the low pressure side.

That is, the swash plate support member 70 has a pair of support portions 73A, 73B arranged separately, and the swash plate 50 has a pair of supported portions 53A, 53B supported by the pair of support portions 73A, 73B of the swash plate support member 70, respectively. Further, oil reservoir C may be formed between one supporting portion 73A and one supported portion 53A, and 2 nd oil reservoir C2 may be formed between the other supporting portion 73B and the other supported portion 53B. According to such an example, the oil reservoir C is formed not only between the 1 st support portion 73A of the swash plate support member 70 on the high pressure side and the 1 st supported portion 53A of the swash plate 50, but also between the 2 nd support portion 73B of the swash plate support member 70 on the low pressure side and the 2 nd supported portion 53B of the swash plate 50, the 2 nd oil reservoir C2. Thereby, the swash plate 50 can be pressed toward the side away from the swash plate support member 70 on both the high pressure side and the low pressure side. Accordingly, the swash plate 50 can be pressed in the substantially axial direction da, and the swash plate 50 can be smoothly deflected.

The 2 nd oil reservoir C2 shown in fig. 3 has a constant area regardless of the orientation of the swash plate 50. However, the configuration of the oil reservoir C described above may be adopted such that the area of the 2 nd oil reservoir C2 between the swash plate 50 and the swash plate support member 70 changes according to the inclination of the swash plate 50.

In this modification, the area of the 2 nd oil reservoir C2 formed between the other supporting portion 73B and the other supported portion 53B can be set smaller than the area of the oil reservoir C formed between the one supporting portion 73A and the one supported portion 53A. According to such an example, the force pressing the swash plate 50 to the side away from the swash plate support member 70 on the high pressure side can be made larger than the force pressing the swash plate 50 to the side away from the swash plate support member 70 on the low pressure side. Accordingly, the swash plate 50 can be pressed in the axial direction da with further high accuracy, and the swash plate 50 can be deflected more smoothly.

Further, another modification will be described. In the specific example of the hydraulic device 10 described above, the example in which the pressure oil introduction path P has the 1 st introduction path Pa communicating with the 1 st concave portion 60 and the 2 nd introduction path Pb communicating with the 2 nd concave portion 80 is shown, but the present invention is not limited to this example. In the case where the communication state between the 1 st recess portion 60 and the 2 nd recess portion 80 is maintained regardless of the inclination of the swash plate 50, either one of the 1 st introduction path Pa and the 2 nd introduction path Pb may be omitted.

As described above, the hydraulic device 10 can be applied to a hydraulic pump or a hydraulic motor, and when applied to these, it is possible to effectively suppress performance degradation of the hydraulic device that occurs with the swash plate deflecting operation.