CN112443467A

CN112443467A - Cylinder block, hydraulic device, construction machine, and method for manufacturing cylinder block

Info

Publication number: CN112443467A
Application number: CN202010845483.0A
Authority: CN
Inventors: 赤见俊也; 山本哲生
Original assignee: Nabtesco Corp
Current assignee: Nabtesco Corp
Priority date: 2019-09-03
Filing date: 2020-08-20
Publication date: 2021-03-05
Also published as: JP2021038707A; KR20210028095A; JP7378246B2

Abstract

The invention provides a cylinder block, a hydraulic device, a construction machine, and a method for manufacturing the cylinder block. The cylinder (20) has: a cylinder wall surface section (CW) and a cylinder bottom surface section (CB) which form a cylinder chamber (21), the cylinder chamber (21) extending in one Direction (DX) and having one side opening in the one direction; a port wall surface Portion (PW) that forms a Connection Port (CP) that is open on the other side in the one direction and that communicates with the cylinder chamber (21); and an inclined surface portion (IS) inclined with respect to a direction. The inclined surface section (IS) IS connected to at least a part of the port wall surface and the cylinder wall surface, and the port wall surface IS located at a position that IS offset from the cylinder chamber (21) in a direction orthogonal to the one direction.

Description

Cylinder block, hydraulic device, construction machine, and method for manufacturing cylinder block

Technical Field

The present invention relates to a cylinder block, a hydraulic device, a construction machine, and a method for manufacturing a cylinder block for a hydraulic device.

Background

For example, as disclosed in JP1999-22654A, a hydraulic device, typically a hydraulic device, is known, which includes a rotatable cylinder block and a piston disposed in a cylinder chamber of the cylinder block. In this hydraulic device, the piston moves back and forth with the rotation of the cylinder block, and the volume of the cylinder chamber changes. The cylinder block is provided with a connection port communicating with each cylinder chamber. A valve plate having a plurality of ports is disposed adjacent to the cylinder block. Each cylinder chamber is connected to a port of the valve plate via a connection port as the cylinder block rotates. The working fluid flows into and out of the cylinder chambers by connecting the ports and the ports of the valve plate.

However, if a step is formed between the connection port and the cylinder chamber, the flow of the working fluid (e.g., working oil) between the connection port and the cylinder chamber is disturbed. If the working fluid cannot flow smoothly between the connection port and the cylinder chamber in this manner, various problems may occur. For example, in the case where the hydraulic device is used as a pump, cavitation occurs in the cylinder chamber on the low pressure side. In addition, when the hydraulic device is used as a motor, pressure loss occurs to reduce the output.

Disclosure of Invention

The present invention is made in consideration of the above points, and aims to smooth the flow of the working fluid between the connection port of the cylinder block and the cylinder chamber.

A cylinder block according to claim 1 of the present invention is a cylinder block in which a plurality of cylinder portions are arranged in a circumferential direction around a rotation axis, the cylinder portion including:

a cylinder wall surface portion that forms a cylinder chamber that is formed along a direction and that opens in one side in the direction;

a cylinder bottom surface portion formed on the other side in the one direction of the cylinder wall surface portion and having an opening portion at least in part;

a port wall surface portion that forms a connection port connected to the opening portion; and

an inclined surface portion that connects at least a part of the port wall surface portion and at least a part of the cylinder wall surface portion and is inclined with respect to the one direction.

The cylinder block according to claim 2 of the present invention includes:

a cylinder wall surface portion that forms a plurality of cylinder chambers, respectively, which are provided separately in a circumferential direction centered on an axis along a direction and each open on one side in the direction;

a cylinder bottom surface portion connected to the cylinder wall surface portion from the other side in the one direction;

a port wall surface portion that forms a connection port that communicates with the cylinder chamber; and

The cylinder block according to claim 3 of the present invention includes:

a plurality of cylinder wall surface portions that form a plurality of cylinder chambers, respectively, which are provided separately in a circumferential direction around an axis parallel to a direction and each open on one side in the direction;

a plurality of cylinder bottom surface portions connected to the cylinder wall surface portions from the other side in the one direction, and forming the cylinder chambers together with the cylinder wall surface portions;

a plurality of port wall surface portions that form connection ports that are provided so as to correspond to the respective cylinder chambers and that communicate with the cylinder chambers from the other side in the direction; and

and a plurality of inclined surface portions which connect the cylinder wall surface portion of each cylinder chamber and the port wall surface portion of the connection port corresponding to the cylinder chamber and are inclined with respect to the one direction.

The cylinder block according to claim 4 of the present invention includes:

a plurality of port wall surface portions that form connection ports that communicate with the cylinder chambers from the other side in the one direction;

and a plurality of inclined surface portions that connect the cylinder wall surface portion and the port wall surface portion and are inclined with respect to the one direction.

In the cylinder block according to claim 1 to claim 4 of the present invention, an angle formed by the inclined surface portion with respect to a plane orthogonal to the one direction may be larger than an angle formed by the bottom surface portion with respect to a plane orthogonal to the one direction.

In the cylinder block according to claim 1 to claim 4 of the present invention, the cylinder wall surface portion and the port wall surface portion may extend in the direction.

The cylinder block according to claim 1 to claim 4 of the present invention may be one in which,

the cylinder bottom surface portion faces the one side in the one direction,

the inclined surface portion faces the other side in the direction.

In the cylinder according to claim 1 to claim 4 of the present invention, at least a part of the inclined surface portion may have a shape constituting a part of a side surface portion of a cone.

In the cylinder block according to claim 1 to claim 4 of the present invention, the connection port may have a shape that exceeds the cylinder chamber in the circumferential direction of the cylinder block.

the connection port extends linearly and is located at a position deviated at an end portion with respect to the cylinder chamber as viewed from the other side in the one direction,

the inclined surface portion is provided at a position to become the end portion of the connection port.

In the cylinder according to claim 1 to claim 4 of the present invention, the inclined surface may be at an angle of 30 ° or more and 70 ° or less with respect to the one direction.

In the cylinder block according to claim 1 to claim 4 of the present invention, the port wall surface portion may have a roughness smaller than a roughness of the inclined surface portion.

In the cylinder according to claim 1 to claim 4 of the present invention, the inclined surface portion may be provided in a plurality of spaced apart portions.

a port bottom surface portion provided between the plurality of inclined surface portions when viewed from the other side in the one direction, and connecting a part of the port wall surface portion located at a position deviated from the cylinder chamber in a direction orthogonal to the one direction and the cylinder wall surface portion,

the inclined surface portion forms a larger angle with respect to a plane orthogonal to the one direction than the port bottom surface portion forms with respect to a plane orthogonal to the one direction.

In the cylinder according to claim 1 to claim 4 of the present invention, the port wall surface portion may face the other side in the one direction.

In the cylinder block according to claim 1 to claim 4 of the present invention, the inclined surface portion may extend linearly when viewed from the other side in the one direction.

In the cylinder block according to claim 1 to claim 4 of the present invention, the inclined surface portion extending linearly in a view from the other side in the one direction may have a shape in which both end portions thereof form a part of a side surface portion of a cone.

The cylinder block according to claim 5 of the present invention includes:

an inclined surface portion that connects at least a part of the port wall surface portion and at least a part of the cylinder wall surface portion and is inclined with respect to the one direction,

at least a part of the inclined surface portion has a shape constituting a part of a side surface portion of the cone,

the connection port has a shape exceeding the cylinder chamber in the circumferential direction,

the inclined surface portion is at an angle of 30 ° or more and 70 ° or less with respect to the one direction.

The hydraulic device of the present invention includes any one of the cylinder block according to claim 1 to claim 5 of the present invention described above.

The construction machine of the present invention includes any one of the hydraulic devices of the present invention described above.

The method for manufacturing a cylinder block according to claim 1 of the present invention includes the steps of:

a step of advancing a machining tool having a tapered tip portion to one side in a direction to form a hole in a material, the hole including an inclined surface portion inclined with respect to the one direction and opening to the other side in the direction;

and a step of cutting the raw material from the one side in the one direction to form a cylinder chamber, the cylinder chamber being formed so as to be connected to the hole at the inclined surface portion.

In the method of manufacturing a cylinder block for a hydraulic apparatus according to claim 1 of the present invention, either the formation of the cylinder chamber or the formation of the hole may be performed first.

A method for manufacturing a cylinder block according to claim 2 of the present invention includes the steps of:

a step of preparing a raw material including a cylinder chamber having one side open in one direction;

and a step of advancing a machining tool having a tapered tip end portion from the other side in the one direction to the one side to form a hole in the material, the hole including an inclined surface portion inclined with respect to the one direction and connected to the cylinder chamber.

In the step of forming the hole in the method for manufacturing a cylinder block according to claim 1 and the method for manufacturing a cylinder block according to claim 2 of the present invention, a plurality of holes may be formed so as to be separated from each other.

The method of manufacturing a cylinder block according to claim 1 and the method of manufacturing a cylinder block according to claim 2 of the present invention may include a step of cutting a portion of the raw material located between the plurality of holes so that the inclined surface portion is at least partially left by moving another machining tool in a direction intersecting the one direction.

In the method of manufacturing a cylinder block according to claim 1 and the method of manufacturing a cylinder block according to claim 2 of the present invention, the surface roughness of the surface portion formed using the other processing tool may be smaller than the roughness of the inclined surface portion formed using the processing tool.

The method of manufacturing a cylinder block according to claim 1 and the method of manufacturing a cylinder block according to claim 2 of the present invention may include a step of moving the machining tool in a direction intersecting the one direction to enlarge the hole.

The method of manufacturing a cylinder block according to claim 1 and the method of manufacturing a cylinder block according to claim 2 of the present invention may include a step of moving a machining tool in the direction intersecting the one direction to reduce the roughness of the hole so as to leave the inclined surface portion at least partially.

According to the present invention, the flow of the working fluid between the connection port of the cylinder block and the cylinder chamber can be smoothed.

Drawings

Fig. 1 is a diagram for explaining an embodiment of the present invention, and is a side view showing an example of a construction machine to which a hydraulic device is applicable.

Fig. 2 is a longitudinal sectional view showing an example of a hydraulic device applicable to the construction machine of fig. 1.

Fig. 3 is a plan view showing a cylinder included in the hydraulic apparatus of fig. 2.

Fig. 4A is a plan view showing an example of a valve plate included in the hydraulic apparatus of fig. 2.

Fig. 4B is a plan view showing another example of a valve plate included in the hydraulic apparatus of fig. 2.

Fig. 5 is a sectional view taken along line V-V of fig. 3.

Fig. 6 is a sectional view taken along line VI-VI of fig. 3.

Fig. 7 is a sectional view for explaining an example of a method of forming a connection port and a cylinder chamber of the cylinder block of fig. 5.

Fig. 8 is a sectional view for explaining an example of a method of forming a connection port and a cylinder chamber of the cylinder block of fig. 5.

Fig. 9 is a sectional view for explaining an example of a method of forming a connection port and a cylinder chamber of the cylinder block of fig. 5.

Fig. 10 is a sectional view for explaining another example of a method of forming a connection port and a cylinder chamber of the cylinder block of fig. 5.

Fig. 11 is a sectional view for explaining still another example of a method of forming a connection port and a cylinder chamber of the cylinder block of fig. 5.

Fig. 12 corresponds to fig. 5, and shows a modification of the cylinder block.

Fig. 13 is a cross-sectional view similar to fig. 5 showing a reference example of the cylinder block.

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. In the following embodiment, an example in which the hydraulic device of the present embodiment is applied to the hydraulic device 10 will be described, but the present invention is not limited to this example.

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. When the hydraulic device 10 is used as a pump, the hydraulic device 10 pumps 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 where the oil hydraulic device 10 is flexibly applied as a motor, the oil hydraulic device 10 outputs rotation from a 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 shaft member 18 is rotated by power from a power source such as an engine, and the cylinder block 20 coupled to the shaft member 18 by spline fitting or the like is rotated. The piston 25 housed in the cylinder chamber 21 of the cylinder block 20 reciprocates as the cylinder block 20 rotates. By this reciprocating operation of the piston 25, the hydraulic oil is sucked into a part of the cylinder chamber 21, and the hydraulic oil is discharged from the other cylinder chamber 21.

On the other hand, when the hydraulic device 10 is used as a motor, the hydraulic oil is introduced into the cylinder chamber 21 by using an external pump or the like, and the hydraulic oil is discharged from the other cylinder chamber 21. Thereby, the piston 25 reciprocates in the cylinder chamber 21 and moves while sliding on the swash plate. The cylinder 20 rotates in accordance with the operation of the piston 25, and can output rotation from the shaft member 18 fixed to the cylinder 20.

The hydraulic device of the present embodiment can be typically used in a hydraulic circuit provided in a construction machine or a hydraulic device 10 as a drive device, and can be applied to other applications.

As a specific example, fig. 1 shows a hydraulic excavator 90 as an example of a construction machine CM to which the hydraulic device 10 of the present embodiment is applicable. In general, the excavator 90 includes: a lower frame 91 having a crawler belt; an upper frame 92 provided to be rotatable with respect to the lower frame 91; a boom 93 attached to the upper frame 92; an arm 94 attached to the boom 93; and a bucket 95 attached to the arm 94. The

hydraulic cylinders

96A, 96B, and 96C are actuators for a boom, an arm, and a bucket, and drive the boom 93, the arm 94, and the bucket 95, respectively. When the upper frame 92 is rotated, the rotational driving force from the rotating device 97 is transmitted to the upper frame 92. When the hydraulic excavator 90 is to be driven, the rotational driving force from the driving device 98 is transmitted to the crawler belts of the lower frame 91. The turning device 97 and the traveling device 98 are constituted by hydraulic motors that output rotation by inputting hydraulic pressure.

The hydraulic device 10 can be used as a pump for supplying pressure oil to hydraulic actuators such as the

hydraulic cylinders

96A, 96B, and 96C, the turning device 97, and the traveling device 98. The hydraulic device 10 may be applied to the turning device 97 and the traveling device 98, and supplies hydraulic pressure to output rotational driving force.

Next, the hydraulic device 10 will be explained.

The hydraulic device 10 of the swash plate type shown in the drawing includes a housing 15, a shaft member 18, a cylinder block 20, a piston 25, a valve plate 30, a tilt adjusting mechanism 35, and a swash plate 50 as main components. Hereinafter, each constituent element will be described.

As shown in fig. 2, the housing 15 includes a 1 st housing module 15a and a 2 nd housing module 15b fixed to the 1 st housing module 15 a. The 1 st housing module 15a and the 2 nd housing module 15b are fixed to each other using a fastener such as a bolt. The housing 15 has a housing space S formed therein. The cylinder block 20, the piston 25, the valve plate 30, the yaw adjusting 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 is formed with a 1 st oil passage 11 and a 2 nd oil passage 12. The 1 st oil passage 11 and the 2 nd oil passage 12 communicate 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 oil passage 11 and the 2 nd oil passage 12 are indicated by lines, and actually have appropriate sectional dimensions corresponding to the supply and discharge of the hydraulic oil to and from the cylinder chambers 21 of the cylinder block 20. The 1 st oil passage 11 and the 2 nd oil passage 12 are provided so as to penetrate the casing 15 from inside the casing 15 to outside the casing 15. The 1 st oil passage 11 and the 2 nd oil passage 12 communicate with an actuator, an oil pressure source, and the like provided outside the hydraulic device 10.

The shaft member 18 is rotatably supported by the housing 15 by

bearings

19a and 19 b. The shaft member 18 is rotatable about its central axis line as a rotation axis RA. One end of the shaft member 18 is rotatably supported by the 1 st housing block 15a via a bearing 19 b. The other end of the 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 a portion where the shaft member 18 penetrates the housing 15, a seal member is provided between the housing 15 and the shaft member 18, and prevents the working oil from flowing out of the housing 15. A portion of the 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 block 20 is penetrated by the shaft member 18. The cylinder block 20 is coupled to the shaft member 18 by spline fitting, for example. The cylinder block 20 is rotatable about the rotation axis RA in synchronization with the 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 opens on the swash plate 50 side in the axial direction DA parallel to the rotation axis RA. In the illustrated example, each cylinder chamber 21 extends parallel to the axial direction DA. Further, a connection port CP is formed corresponding to each cylinder chamber 21. The connection port CP is open on the side of the valve plate 30 in the axial direction DA. Since the connection ports CP are connected to the corresponding cylinder chambers 21, the cylinder chambers 21 are opened toward the valve plate 30 in the axial direction DA. The cylinder portion 21X is formed by a cylinder chamber 21 and a connection port CP. The plurality of cylinder portions 21X are provided at intervals in a circumferential direction DC around the rotation axis RA. Further, with respect to the cylinder chamber 21 and the connection port CP, further details are discussed later.

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 the axial direction DA relative to the cylinder 20. That is, the piston 25 can advance toward the swash plate 50 in the axial direction DA to increase the volume of the cylinder chamber 21. The piston 25 can be retracted 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. As shown in fig. 2, the shaft member 18 penetrates through a central hole 51 of the swash plate 50. The swash plate 50 has a contact surface CS that contacts the shoe 26 that rotates with rotation of the shaft member 18. The contact surface CS is located opposite to the cylinder 20 and the piston 25. The swash plate 50 is supported in the housing 15 such that the contact surface CS can be inclined with respect to a surface perpendicular to the rotation axis RA.

As shown in fig. 2, the shoe 26 is provided on the contact surface CS of the swash plate 50. The shoe 26 holds the end (head) of the piston 25. Specifically, an end portion that is one end of the piston 25 is formed in a spherical shape. The slipper 26 has a hole that can receive approximately half of the spherical end. The shoe 26 holding the end of the piston 25 can move on the contact surface CS of the swash plate 50 while contacting the contact surface CS.

The hydraulic device 10 further includes a damper 27 disposed in the housing 15. The baffle 27 is an annular plate-shaped member. The baffle plate 27 is penetrated by the shaft member 18 and supported by the shaft member 18. The support portion 18a of the shaft member 18 that supports the baffle plate 27 is formed in a curved surface shape. Therefore, the baffle plate 27 can change its orientation in a state of being supported by the shaft member 18. As shown in fig. 2, the plate-like flapper 27 is inclined along the contact surface CS 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 shaft member 18 and the shutter 27. The retainer 27 is pressed toward the swash plate 50 in the axial direction DA by the piston pressing member 28. As a result, the retainer 27 can press the shoe 26 and the piston 25 against the contact surface CS of the swash plate 50. The shaft member 18 is pressed together with the cylinder block 20 toward the valve plate 30 in the axial direction DA by the piston pressing member 28. As a result, the cylinder block 20 is pressed against the valve plate 30.

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 shaft member 18. The valve plate 30 has two or more ports. Each port communicates with the 1 st oil passage 11 or the 2 nd oil passage 12. The ports are formed, for example, along an arc centered on the rotation axis RA, and sequentially face the connection ports CP corresponding to the respective cylinder chambers 21 as the cylinder block 20 rotates. As a result, the connection between each cylinder chamber 21 and the 1 st oil passage 11 and the 2 nd oil passage 12 is switched according to the rotation state of the cylinder block 20.

Here, fig. 3 is a plan view showing the cylinder block 20 from the side closer to the valve plate 30 in the axial direction DA. That is, fig. 3 shows a surface of the cylinder block 20 facing the valve plate 30, and a plurality of connection ports CP are opened on the surface. In fig. 3, the cylinder chamber 21 is shown by a solid line and a broken line. In the illustrated example, each connection port CP extends in an elongated manner in a circumferential direction DC about the rotation axis RA. Each of the connection ports CP overlaps the corresponding cylinder chamber 21 at a central portion in the longitudinal direction thereof along the circumferential direction DC as viewed from the side of the valve plate 30 in the axial direction DA shown in fig. 3. On the other hand, each connection port CP is offset in the circumferential direction DC with respect to the corresponding cylinder chamber 21 at both end portions in the longitudinal direction along the circumferential direction DC.

In particular, in the example shown in fig. 3, the position of the connection port CP along the radial direction DR orthogonal to the rotation axis RA is not necessarily the same. The connection ports CP arranged along the circumferential direction DC are alternately arranged at positions on the inner side in the radial direction DR and at positions on the outer side in the radial direction DR. That is, the inner connection ports CPA located on the inner side in the radial direction and the outer connection ports CPB located on the outer side in the radial direction are alternately arranged in the circumferential direction DC. By changing the arrangement in the radial direction DR of the connection ports CP adjacent in the circumferential direction DC, the length of each connection port CP along the circumferential direction DC can be ensured to be long. By extending the connection port CP in the circumferential direction DC, the connection between the connection port CP and the port of the valve plate 30 can be ensured for a long period of time.

The inner side in the radial direction DR refers to a side of the radial direction DR close to the rotation axis RA, and the outer side in the radial direction DR refers to a side of the radial direction DR far from the rotation axis RA.

Next, fig. 4A and 4B are plan views of the valve plate 30 that can be used together with the cylinder block 20 shown in fig. 3, from the housing space S. The valve plate 30 has a 1 st port 31 connected to the 1 st oil passage 11 and a 2 nd port 32 connected to the 2 nd oil passage 12. The 1 st port 31 and the 2 nd port 32 each extend in the circumferential direction DC. The range in the radial direction DR of the 1 st port 31 and the 2 nd port 32 at least partially overlaps with the range in which the connection port CP is arranged in the radial direction DR. Thus, by rotating the cylinder block 20, the connection port CP alternately communicates with the 1 st port 31 and the 2 nd port 32.

In particular, in the example shown in fig. 4A, the 1 st port 31 communicating with the 1 st oil passage 11 has two 1 st inner ports 31A and 1 st outer ports 31B at different positions in the radial direction DR. The 1 st inner port 31A located on the inner side in the radial direction DR can communicate only with the inner connection port CPA while being blocked with respect to the 1 st outer port 31B. On the other hand, the 1 st outer port 31B located on the outer side in the radial direction DR can communicate only with the outer connection port CPB, while being blocked from the 1 st inner port 31A. In this example, the 1 st oil passage 11 is also split into two systems, one of the 1 st oil passages 11 communicates with the 1 st inner port 31A, and the other of the 1 st oil passages 11 communicates with the 1 st outer port 31B. On the other hand, both the inner connection port CPA and the outer connection port CPB can communicate with the common 2 nd port 32 of the valve plate 30.

By using the valve plate 30 shown in fig. 4A, for example, when the hydraulic device 10 is used as a pump, the working oil can be discharged to the 1 st oil passage 11 of the two paths. For example, the hydraulic oil flowing out of the inner connection port CPA can be supplied to the 1 st passage of the 1 st oil passage 11 via the 1 st inner port 31A, and the hydraulic oil flowing out of the outer connection port CPB can be supplied to the 2 nd passage separated from the 1 st passage of the 1 st oil passage 11 via the 1 st outer port 31B. For example, when the hydraulic device 10 is used as a motor, the hydraulic oil flowing from the 1 st oil passage 11 of the two passages can be supplied to the other cylinder chamber 21. For example, the hydraulic oil supplied from the 1 st passage of the 1 st oil passage 11, for example, the hydraulic oil supplied from the 1 st pump can be supplied to the cylinder chamber 21 connected to the inner connection port CPA via the 1 st inner port 31A. The hydraulic oil supplied from the 2 nd path of the 1 st oil passage 11, for example, the hydraulic oil supplied from the 2 nd pump can be supplied to the cylinder chamber 21 connected to the outer connection port CPB via the 1 st outer port 31B.

On the other hand, in the example of the valve plate 30 shown in fig. 4B, the 1 st port 31 can communicate with both the inner connection port CPA and the outer connection port CPB, similarly to the 2 nd port 32.

Here, the operation of the hydraulic device 10 will be described. When the hydraulic device 10 functions as a pump, the shaft member 18 rotates about the rotation axis RA by 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.

During a period in which the piston 25 retreats from a position (top dead center) at which it extends out to the maximum extent from 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 this period, the cylinder chamber 21 housing the piston 25 that is moving backward is connected to, for example, the 1 st oil passage 11 via the connection port CP and the 1 st port 31 of the valve plate 30, and the working oil is discharged from the cylinder chamber 21. The 1 st oil passage 11 is connected to an external actuator or the like as a high-pressure side flow passage.

On the other hand, the capacity of the cylinder chamber 21 in which the piston 25 is accommodated increases while the piston 25 advances from the bottom dead center to the top dead center. During at least a part of this period, the cylinder chamber 21 housing the advancing piston 25 is connected to, for example, the 2 nd oil passage 12 via the connection port CP and the 2 nd port 32 of the valve plate 30, and the working oil is sucked into the cylinder chamber 21. The 2 nd oil passage 12 is connected as a low-pressure side flow passage to a tank or the like for storing hydraulic oil.

When the hydraulic device 10 functions as a hydraulic motor, the hydraulic oil discharged from an external pump, not shown, to the 1 st oil passage 11 is supplied into the cylinder chamber 21 of the hydraulic device 10 through the 1 st port 31 of the valve plate 30 and the connection port CP. 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 1 st port 31 of the valve plate 30 connects the cylinder chamber 21 in which the piston 25 is accommodated in the path from the bottom dead center to the top dead center to the 1 st oil passage 11 on the high pressure side. In this way, the cylinder block 20 can be rotated by the supply of the hydraulic oil from the external pump, and the rotational force can be output via the shaft member 18.

The 2 nd port 32 of the valve plate 30 connects the cylinder chamber 21 in which the piston 25 is accommodated in the path from the top dead center to the bottom dead center to the 2 nd oil passage 12 on the low pressure side. Therefore, during the period in which the piston 25 retreats from the top dead center to the bottom dead center, the working oil in the cylinder chamber 21 for accommodating the piston 25 can be discharged to the 2 nd oil passage 12 via the connection port CP and the 2 nd port 32 of the valve plate 30. The hydraulic oil discharged from the hydraulic device 10 is collected into a tank or the like connected to the 2 nd oil passage 12.

In the hydraulic device 10 described above, the contact surface CS 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, which is more strictly expressed as the magnitude of the inclination angle θ i (see fig. 2) of the contact surface CS 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 contact surface CS of the swash plate 50 is perpendicular to the axial direction DA, that is, if the inclination angle θ i is 0 °, theoretically, no output can be obtained from the hydraulic device 10.

Therefore, the swash plate 50 is held so as to be able to deflect in the illustrated hydraulic device 10. The yaw adjustment mechanism 35 includes a swash plate pressing member 36 and a swash plate drive unit 37. The swash plate pressing member 36 and the swash plate drive device 37 are disposed in the housing 15 so as to be separated in the radial direction DR with the shaft member 18 interposed therebetween. The swash plate pressing member 36 presses the swash plate 50 so as to increase the inclination angle θ i, in particular, so as to rotate the swash plate 50 counterclockwise in fig. 2. The swash plate drive unit 37 presses the swash plate 50 so as to decrease the inclination angle θ i, particularly, so as to rotate the swash plate 50 clockwise in fig. 2. The output from the swash plate drive device 37 can be adjusted. The inclination angle θ i of the swash plate 50 can be controlled by adjusting the output from the swash plate drive device 37.

In the illustrated example, the connection port CP extends in the circumferential direction DC when viewed from the side closer to the valve plate 30 in the axial direction DA (see fig. 3). Therefore, the connection between each cylinder chamber 21 of the cylinder block 20 and the

ports

31 and 32 of the valve plate 30 rotating at high speed can be stably secured. On the other hand, the connection port CP elongated in the circumferential direction DC partially overlaps the cylinder chamber 21 when viewed from the valve plate 30 side in the axial direction DA, but is partially located at a position offset from the cylinder chamber 21. That is, the connection port CP elongated in the circumferential direction DC has a shape that exceeds the cylinder chamber 21 in the circumferential direction DC when viewed from the valve plate 30 side in the axial direction DA. In further other words, as shown in fig. 3, the connection port CP overlaps the corresponding cylinder chamber 21 at one portion and does not overlap the cylinder chamber 21 at the other portion in the projection along the axial direction DA. The connection port CP is not limited to the connection port CP having a shape elongated in the circumferential direction DC, and may be at a position at least partially offset from the cylinder chamber 21 when viewed from the side closer to the valve plate 30 in the axial direction DA due to, for example, a positional relationship with the

ports

31 and 32 of the valve plate 30.

In the cylinder block 120 shown in fig. 13, the connection port CP is expanded from the cylinder chamber 121 by a step. That is, a port bottom surface portion PB facing the valve plate side in the axial direction DA is provided between the port wall surface portion PW of the connection port CP and the cylinder wall surface portion CW of the cylinder chamber 121. The port bottom surface portion PB extends in a direction orthogonal to the substantially axial direction DA.

However, in the example shown in fig. 13, it is difficult for the hydraulic oil to smoothly flow between the cylinder chamber 121 and the portion of the connection port CP that is expanded by the step. In the vicinity of the port wall PW and the port bottom PB, the flow of the working oil may be greatly disturbed or stagnated. In the cylinder chamber 121 on the low pressure side, for example, the cylinder chamber 121 on the low pressure side of the hydraulic device 110 serving as a pump, smooth flow of the hydraulic oil is blocked, the pressure is reduced, and cavitation may occur. When cavitation occurs and bubbles are generated, the entire flow of the hydraulic oil is stopped, which also causes abnormal noise and erosion, and on the other hand, a pressure loss occurs in the flow of the hydraulic oil between the connection port CP and the cylinder chamber 121 in the cylinder chamber 121 on the high-pressure side. Such pressure loss generated in the flow path deteriorates the performance of the hydraulic device 110 used as a pump or a motor, and makes it difficult to obtain a desired output from the hydraulic device 110.

On the other hand, according to the present embodiment, a study is made to smoothen the flow between the cylinder chamber 21 and the connection port CP. This study will be described below mainly with reference to fig. 5 to 12. Fig. 5 is a cross-sectional view showing a cross-section along the line V-V in fig. 3. That is, fig. 5 is a sectional view showing the cylinder block 20 in a section along the longitudinal direction of the inner connection port CPA. Fig. 6 is a cross-sectional view taken along line VI-VI in fig. 3. That is, fig. 6 is a sectional view showing the cylinder block 20 in a section along the longitudinal direction of the outer connection port CPB.

First, as shown in fig. 2 and 3, the cylinder chamber 21 has a substantially cylindrical inner shape. The cylinder chamber 21 is divided (formed) by a cylinder wall surface portion CW corresponding to the side surface of the cylinder and a cylinder bottom surface portion CB corresponding to the bottom surface of the cylinder. The cylinder bottom surface portion CB faces the swash plate 50 in the axial direction DA. In the illustrated example, the cylinder wall surface portion CW extends parallel to the rotation axis RA, and the cylinder bottom surface portion CB is typically orthogonal to the rotation axis RA.

On the other hand, as described above, the connection port CP extends linearly along the circumferential direction DC and opens on the valve plate 30 side in the axial direction DA. The connection port CP has a port wall portion PW extending parallel to the rotation axis RA. The connection port CP is partially located at a position offset from the cylinder chamber 21 as viewed from the side closer to the valve plate 30 in the axial direction DA shown in fig. 3. The connection port CP has a port bottom surface portion PB at a position offset from the cylinder chamber 21. The port bottom surface portion PB is typically orthogonal to the rotation axis RA.

As shown in fig. 5 and 6, the connection port CP communicates with the cylinder chamber 21 through the opening OP on the swash plate 50 side in the axial direction DA. In the present embodiment, the cylinder block 20 has the inclined surface portion IS. The inclined surface portion IS connected to at least a part of the port wall surface portion PW located at a position deviated from the cylinder chamber 21 in the direction orthogonal to the axial direction DA and the cylinder wall surface portion CW. The inclined surface portion IS faces the valve plate 30 side in the axial direction DA. That IS, in the present embodiment, the port wall surface PW of the connection port CP and the cylinder wall surface CW of the cylinder chamber 21 can be smoothly connected by the inclined surface IS. By connecting the cylinder wall surface portion CW and the port wall surface portion PW at least partially via the inclined surface portion IS, the flow of the hydraulic oil between the cylinder chamber 21 and the connection port CP can be smoothed. Thus, when the hydraulic device 10 is applied to a pump, the hydraulic oil can be stably introduced into the cylinder chamber 21 on the low-pressure side. As a result, the self-priming property is improved, and the occurrence of defects such as cavitation can be effectively avoided. When the hydraulic device 10 is applied to a motor or a pump, a pressure loss of the hydraulic oil flowing between the connection port CP and the cylinder chamber 21 can be effectively avoided. As a result, the performance of the hydraulic device 10 that can be flexibly used as a motor or a pump can be improved.

Further, typically, the port bottom surface portion PB and the cylinder bottom surface portion CB are perpendicular to the axial direction DA, but depending on the machining conditions, they may be inclined with respect to the axial direction DA, instead of being perpendicular to the axial direction DA. However, the port bottom surface portion PB and the cylinder bottom surface portion CB each have a very small angle with respect to a plane orthogonal to the rotation axis RA. The angle of the inclined surface portion IS with respect to the plane orthogonal to the axial direction DA IS larger than the angle of the cylinder bottom surface portion CB with respect to the plane orthogonal to the axial direction DA and larger than the angle of the port bottom surface portion PB with respect to the plane orthogonal to the axial direction DA.

In the hydraulic device 10 used as a pump or a motor, the inclination angle θ x (see fig. 5) of the inclined surface portion IS with respect to the axial direction DA IS preferably 30 ° or more and 70 ° or less. When the inclination angle θ x is large, it is difficult to sufficiently and effectively smooth the flow of the hydraulic oil between the cylinder chamber 21 and the connection port CP, as in the example of fig. 13. On the other hand, when the inclination angle θ x is small, the length of the cylinder 20 in the axial direction becomes long, and the machining conditions become severe.

As shown in fig. 5 and 6, the illustrated cylinder block 20 has a plurality of inclined surface portions IS disposed apart from each other. A port bottom surface portion PB IS provided between the plurality of inclined surface portions IS. As shown in fig. 3, the port bottom surface portion PB is located at a position deviated from the cylinder chamber 21 in a direction orthogonal to the axial direction DA when viewed from the valve plate 30 side in the axial direction DA. As shown in fig. 5 and 6, the angle of the inclined surface portion IS with respect to the plane orthogonal to the axial direction DA IS larger than the angle of the port bottom surface portion PB with respect to the plane orthogonal to the axial direction DA.

As described above, the illustrated connection port CP extends linearly, particularly in an arc shape, as viewed from the side closer to the valve plate 30 in the axial direction DA. As shown in fig. 5 and 6, the connection port CP does not overlap the cylinder chamber 21 in the axial direction DA at the end portions thereof in the longitudinal direction, particularly at both end portions. The connection port CP has inclined surface portions IS at both end portions. In addition, the inner connection port CPA shown in fig. 5 has an inclined surface portion IS in an intermediate portion between both end portions, in addition to both end portions as viewed from the valve plate 30 side in the axial direction DA.

In the illustrated example, the inclined surface portion IS has a shape corresponding to at least a part of the surface of the rotating body, which IS tapered from the valve plate 30 side toward the swash plate 50 side in the axial direction DA. Typically, the inclined surface IS has a shape corresponding to a part of a side surface of a cone as a triangular rotating body. As will be discussed later, the inclined surface portion IS having such a shape can be easily and highly accurately manufactured.

The port wall surface portion PW may have a smaller roughness than the inclined surface portion IS. The roughness of the cylinder wall surface portion CW may be smaller than the roughness of the inclined surface portion IS. When the port wall surface portion PW and the cylinder wall surface portion CW are surfaces parallel to the axial direction DA, the port wall surface portion PW and the cylinder wall surface portion CW can be easily finished. The roughness of the port wall portion PW and the roughness of the cylinder wall portion CW are made smaller than the roughness of the inclined surface portion IS by the finish machining, so that the flow of the working oil between the connection port CP and the cylinder chamber 21 can be smoothened more effectively. Further, the smaller the value of the arithmetic mean roughness Ra measured in accordance with JISB0601-2001, the smaller the roughness is evaluated to be.

Next, an example of a method for manufacturing the cylinder block 20 will be described with reference to fig. 7 to 10. In the following manufacturing method, the cylinder chamber 21 and the connection port CP are formed in the material W to manufacture the cylinder block 20. Fig. 7 to 10 show a method of forming the cylinder chamber 21 and the inner connection port CPA in the same cross section as fig. 5.

The inventors of the present invention also studied to manufacture the cylinder block 20 including the above-described inclined surface portion IS by chamfering and casting using a core. However, chamfering, core manufacturing are difficult to perform due to the shape, size, etc. of the cylinder block 20. That IS, in the beveling and the casting using the core, the cylinder block 20 including the inclined surface portion IS cannot be sufficiently and stably manufactured according to the present embodiment. Further, the present inventors have further made extensive studies and, as a result, have found a production method described below.

First, a raw material W constituting the cylinder block 20 is prepared. As an example, the raw material W is made of steel by casting. The material W produced by casting has the same outer shape as the outer shape of the cylinder block 20 to be finally produced. However, in the examples shown in fig. 7 to 9, the cylinder chamber 21 and the connection port CP are not formed in the material W.

Next, as shown in fig. 7, the material W is cut by using a machining tool 60 having a tapered distal end portion 60 a. As the machining tool 60, a drill can be used. As shown in fig. 7, the material W is cut while the machining tool 60 is rotated and advanced from the other side in one direction DX to the one side. At this time, the processing tool 60 rotates about an axis parallel to the one direction DX, advances along the axis, and cuts into the material W. A1 st well HA opened on the other side in one direction DX is formed in a raw material W. The 1 st hole HA HAs a shape of a rotating body (typically, a cone) tapered toward a side in a direction DX at an end portion on the side in the direction DX. That is, the end of the 1 st hole HA on the side in the one direction DX HAs an inclined surface HAs having the same shape as the shape of the surface of the tapered rotating body (typically, a cone). The inclined surface portion IS of the cylinder 20 IS configured to partially remain the inclined surface HAS. In the example shown in fig. 7, a plurality of holes, particularly three 1 st holes HA, are formed in the raw material W so as to be separated from each other.

The one direction DX mentioned in this manufacturing method is a direction parallel to the axial direction DA of the cylinder 20 in the state of being incorporated in the hydraulic apparatus 10. The side in the one direction DX is the side of the swash plate 50 in the axial direction DA of the cylinder block 20 in the state of being incorporated in the hydraulic apparatus 10. The other side in the direction DX is a side of the cylinder block 20 against the valve plate 30 in the axial direction DA in the state of being mounted in the hydraulic apparatus 10.

Thereafter, as shown in fig. 8, the material W is processed using a processing tool (2 nd processing tool) 61 different from the processing tool (1 st processing tool) 60. More specifically, the workpiece W is machined by a machining tool 61 having a flat top end, such as an end mill, in a combined machine tool or the like. In this step, the external shape of the connection port CP extending substantially linearly, typically curvilinearly, is formed. First, as shown by a broken line in fig. 8, while rotating the tool 61 about an axis parallel to the one direction DX, the tool 61 is advanced along the axis, and the tool 61 is inserted into one 1 st hole HA formed in the material W. At this time, the hole formed by the processing tool 61 is the same as or slightly larger than the 1 st hole HA formed by the processing tool 60. Next, the processing tool 61 is advanced in a direction not parallel to (intersecting) the direction DX, typically, in a direction orthogonal to the direction DX. Here, the processing tool 61 is a processing tool as follows: the raw material W can be processed by moving in a direction different from the one direction DX (typically, in a direction orthogonal thereto) in addition to the one direction DX. Specifically, the machining tool 61 is moved from the position indicated by the broken line in fig. 8 to the position indicated by the two-dot chain line in fig. 8 via the position indicated by the solid line in fig. 8. The movement path of the machining tool 61 is formed in an arc shape centered on the rotation axis RA corresponding to the path of the connection port CP when viewed in the axial direction DA. By the movement of the machining tool 61, the portion of the material W located between the plurality of 1 st holes HA is cut and removed.

In the example shown in fig. 7, the processing tool 61 moves between the 1 st holes HA provided in plural. In particular, the processing tool 61 moves between the 1 st holes HA provided at both ends of the 1 st holes HA through the 1 st holes HA in the middle. Thereby, a 2 nd hole HB extending in a linear shape (in the illustrated example, in a curved shape) is formed, and the 2 nd hole HB has a shape substantially the same as the shape of the connection port CP to be manufactured. In addition, the inclined surface HAs of the 1 st hole HA, which HAs the same shape as the shape of the surface of the tapered rotating body (typically, a cone), remains in the 2 nd hole HB at both ends (both ends of the 2 nd hole HB in the circumferential direction DC in the illustrated example) and at the center.

In the step shown in fig. 8, the processing tool (the 2 nd processing tool, the other processing tool) 61 may also be used for finishing. When the machining using the machining tool 61 is performed as the finish machining, the port wall portion PW connected to the port CP is formed by the machining tool 61, but the roughness of the port wall portion PW can be made smaller than the roughness of the surface of the 1 st hole HA extending in the one direction DX formed before the step. As a result, the port wall PW of the connection port CP can have a smaller roughness than the inclined surface HAs of the 1 st hole HA.

Thereafter, as shown in fig. 9, the raw material W is cut from one side in the one direction DX to form a cylinder chamber 21 opened in the one direction DX. In this step, a cutting tool 62 made of an end mill or a drill can be used. The cylinder chamber 21 can be formed by rotating the cutting tool 62 about an axis parallel to the first direction DX and advancing the cutting tool 62 along the axis. At this time, the cutting tool 62 is advanced in one direction DX to a position overlapping the 2 nd hole HB. The cylinder chamber 21 and the connection port CP thus formed are formed, and the cylinder chamber 21 communicates with the connection port CP.

As described with reference to fig. 3, the connection port CP is located at a position that is at least partially offset from the cylinder chamber 21 in a direction orthogonal to the one direction DX when viewed from the other side in the one direction DX. The position deviated from the cylinder chamber 21 includes the inclined surface HAs of the 1 st hole HA. As a result, a cylinder chamber 21 connected to the 2 nd port HB (connection port CP) at the inclined surface HAS is formed. As described above, the inclined surface portion IS formed by the remaining portion of the inclined surface HAS, and finally, the inner connection port CPA and the cylinder chamber 21 shown in fig. 5 can be formed.

Further, the outer connection port CPB and the cylinder chamber 21 shown in fig. 6 can be formed by the same steps as the method described above. However, the method of forming the outer connection port CPB differs from the method of forming the inner connection port CPA in the following points: the positions of formation of the 1 st holes HA are shifted outward in the radial direction, and only two 1 st holes HA are formed. In fig. 6, a processing tool 60 used for forming the 1 st hole HA is shown by a two-dot chain line. With the outer connection port CPB shown in fig. 6, a portion located at a position deviated from the cylinder chamber 21 as viewed in the axial direction DA of the connection port CP becomes smaller as compared with the inner connection port CPA shown in fig. 5. As a result, the inclined surface portion IS becomes smaller for the outside connection port CPB than for the inside connection port CPA.

The manufacturing method described above is an example of the method for manufacturing the cylinder block 20 described above, and can be modified. For example, after machining using the machining tool 61 (the 2 nd machining tool, another machining tool), the port wall PW of the connection port CP and the cylinder wall CW of the cylinder chamber 21 may be further finished using a finishing machining tool. The finish machining of the port wall portion PW and the cylinder wall portion CW extending in the one direction DX can be performed relatively easily. By the finish machining, the roughness of the port wall surface PW and the cylinder wall surface CW can be reduced, and thereby the flow of the working oil between the connection port CP and the cylinder chamber 21 can be smoothened more effectively.

In the above embodiment, the processing for forming the 1 st hole HA, the processing for forming the 2 nd hole HB, and the processing for forming the cylinder chamber 21 are performed in this order. However, the order of the processing for forming the 1 st hole HA, the processing for forming the 2 nd hole HB, and the processing for forming the cylinder chamber 21 can be appropriately changed without being limited to this example.

For example, first, the cylinder chamber 21 is formed in the material W, and as shown in fig. 10, the 1 st hole HA may be formed in the material W in which the cylinder chamber 21 is formed by using the machining tool 60. In the example shown in fig. 10, two 1 st holes HA are formed in the material W in which the cylinder chamber 21 is formed by a machining tool 60 shown by a broken line. Further, in this example, the processing tool 60 indicated by a solid line is moved in the first direction DX to a position indicated by a two-dot chain line, thereby forming the third 1 st hole HA indicated by a two-dot chain line. Further, in the example shown in fig. 10, a process of expanding the 1 st hole HA to create the connection port CP is performed on the material W in which the cylinder chamber 21 and the 1 st hole HA are formed, using the machining tool 61.

In the example described with reference to fig. 10, the cylinder chamber 21 may be formed not by cutting the material W but by forming a cast hole in the cylinder chamber 21. That is, the material W shown in fig. 10 may be cast in a shape in which the concave portion 21A constituting the cylinder chamber 21 is formed.

Further, as shown in fig. 11, after the 1 st hole HA is formed using the tool 60 having the tapered distal end portion 60a, the tool 60 with the raw material W cut therein may be moved in a direction not parallel to the one direction DX (typically, in a direction orthogonal to the one direction DX) to form the 2 nd hole HB. After that, the connection port CP and the cylinder chamber 21 shown in fig. 12 can be formed through the step of forming the cylinder chamber 21 in the material W. Fig. 12 is a view corresponding to fig. 5, showing the cylinder block 20 in a section along the line V-V of fig. 5. In the example shown in fig. 12, the inclined surface portion IS extends linearly when viewed from the other side in the axial direction DA. The inclined surface portion IS linearly extended in the other side in the axial direction DA IS maintained in a state where the inclined surface HAs of the 1 st hole HA having the same shape as the shape of the surface of the tapered rotating body (typically, a cone) remains at both end portions. The inclined surface IS extending linearly in the other direction in the axial direction DA HAS an inclined surface HAS inclined at a constant inclination angle corresponding to the distal end portion 60a of the working tool 60 at each position in the middle portion between both end portions thereof.

In the above-described embodiment, the cylinder 20 includes: a cylinder wall surface portion CW and a cylinder bottom surface portion CB that form a cylinder chamber 21 extending in one direction DX (axial direction DA) and open on one side in the one direction DX (axial direction DA); a port wall PW that forms a connection port CP that opens on the other side in one direction DX and communicates with the cylinder chamber 21; and an inclined surface portion IS inclined with respect to a direction DX (axial direction DA). The inclined surface portion IS connected to at least a part of the port wall surface portion PW located at a position deviated from the cylinder chamber 21 in a direction orthogonal to the one direction DX (axial direction DA) and the cylinder wall surface portion CW. According to this embodiment, the port wall PW of the connection port CP and the cylinder wall CW of the cylinder chamber 21 can be smoothly connected to each other by the inclined surface IS. Therefore, the flow of the hydraulic oil between the connection port CP and the cylinder chamber 21 can be effectively smoothed. This enables the pump to stably introduce the working oil into the low-pressure side cylinder chamber 21. As a result, the self-priming property is improved, and the occurrence of defects such as cavitation can be effectively avoided. In addition, the motor can effectively avoid a pressure loss of the hydraulic oil flowing between the connection port CP and the cylinder chamber 21. As a result, the performance of the hydraulic device 10 can be improved.

In a specific example of the above-described one embodiment, at least a part of the inclined surface portion IS has a shape constituting a part of a side surface of a cone. According to this specific example, the flow of the hydraulic oil between the connection port CP and the cylinder chamber 21 can be effectively smoothed by effectively avoiding the flow of the hydraulic oil from being disturbed between the connection port CP and the cylinder chamber 21.

In a specific example of the above-described one embodiment, the connection port CP has a shape that exceeds the cylinder chamber 21 in the circumferential direction DC. In other words, the connection port CP extends linearly and IS located at a position offset from the cylinder chamber 21 at the end portion when viewed from the other side in the axial direction DA (the first direction DX), and the inclined surface portion IS provided at a position that becomes the end portion of the connection port CP. According to this specific example, the connection port CP can have an elongated shape along the

ports

31 and 32 formed in the valve plate 30, for example. Therefore, the flow of the hydraulic oil between the connection port CP and the valve plate 30 can be smoothed. Further, since the inclined surface portion IS provided at the end portion of the elongated connection port CP, the flow of the hydraulic oil can be effectively prevented from being disturbed at the end portion of the elongated connection port CP, and the flow of the hydraulic oil between the connection port CP and the cylinder chamber 21 can be more effectively smoothed.

In a specific example of the above-described embodiment, the inclined surface portion IS forms an angle of 30 ° or more and 70 ° or less with respect to the axial direction DA (the first direction DX). According to this specific example, the flow of the hydraulic oil between the connection port CP and the cylinder chamber 21 can be smoothed more effectively.

In a specific example of the above-described embodiment, the port wall surface portion PW has a smaller roughness than the inclined surface portion IS. According to this specific example, the roughness of the port wall surface PW of the connection port CP can be made small. This can smooth the flow of the hydraulic oil between the connection port CP and the cylinder chamber 21 more effectively.

In a specific example of the above-described one embodiment, the inclined surface portions IS are provided in plural spaced apart relation to each other. According to this specific example, the plurality of inclined surface portions IS are provided in a dispersed manner. Therefore, the flow of the hydraulic oil between the connection port CP and the cylinder chamber 21 can be smoothened more effectively.

In a specific example of the above-described one embodiment, the inclined surface portion IS extends linearly as viewed from the other side in the one direction DX (axial direction DA). According to this specific example, since the inclined surface portion IS provided over a wide range, the flow of the hydraulic oil between the connection port CP and the cylinder chamber 21 can be made smoother more effectively.

In a specific example of the above-described one embodiment, the inclined surface portion IS linearly extending in a view from the other side in the one direction DX (axial direction DA) has a shape in which both end portions thereof form a part of a side surface of a cone. According to this specific example, the flow of the hydraulic oil between the connection port CP and the cylinder chamber 21 can be effectively smoothed by effectively avoiding the flow of the hydraulic oil from being disturbed between the connection port CP and the cylinder chamber 21.

In one embodiment described above, the method for manufacturing a cylinder block includes the steps of: a step of forming a 1 st hole HA in the material W by advancing a working tool 60 having a tapered distal end portion 60a to one side in a first direction DX (axial direction DA), the 1 st hole HA including an inclined surface HAs inclined with respect to the first direction DX (axial direction DA) and opening to the other side in the first direction DX; and a step of cutting the material W from one side in one direction DX (axial direction DA) to form a cylinder chamber 21, wherein the cylinder chamber 21 is formed to be connected with the holes HA and HB at the inclined surface HAS. Alternatively, in one embodiment, the method includes the steps of: a step of preparing, for example, casting a raw material W including a cylinder chamber 21 having one side opened in a direction DX (axial direction DA); and a step of advancing the machining tool 60 having the tapered distal end portion 60a from the other side to the one side in one direction DX (axial direction DA) to form a hole HA in the raw material W, the hole HA including an inclined surface HAs inclined with respect to the one direction DX and connected to the cylinder chamber 21. According to such an embodiment, the port wall surface PW of the connection port CP formed by the bores HA and HB and the cylinder wall surface CW of the cylinder chamber 21 can be smoothly connected by the inclined surface IS. Therefore, the flow of the hydraulic oil between the connection port CP and the cylinder chamber 21 can be effectively smoothed. This enables the pump to stably introduce the working oil into the low-pressure side cylinder chamber 21. As a result, the self-priming property is improved, and the occurrence of defects such as cavitation can be effectively avoided. In addition, the motor can effectively avoid a pressure loss of the hydraulic oil flowing between the connection port CP and the cylinder chamber 21. As a result, pump performance can be improved.

In a specific example of the above-described one embodiment, in the step of forming the 1 st well HA, a plurality of 1 st well HAs are formed so as to be separated from each other. According to this specific example, the plurality of inclined surface portions IS are provided in a dispersed manner. Therefore, the flow of the hydraulic oil between the connection port CP and the cylinder chamber 21 can be smoothened more effectively.

In a specific example of the above-described one embodiment, the method of manufacturing the cylinder block further includes a step of moving the working tool 61 (the 2 nd working tool, the other working tool) in a direction not parallel to the one direction DX (the axial direction DA) to cut a portion of the material W located between the plurality of 1 st holes HA so that the inclined surface HAS remains at least partially. According to this specific example, the cross-sectional area of the connection port CP formed by the holes HA and HB can be increased. Therefore, the flow of the hydraulic oil between the connection port CP and the cylinder chamber 21 can be smoothened more effectively.

In a specific example of the above-described one embodiment, the roughness of the surface formed using the processing tool 61 (the 2 nd processing tool, the other processing tool) is smaller than the roughness of the inclined surface HAS formed using the processing tool 60. According to this specific example, the roughness of the port wall PW of the connection port CP formed by the holes HA and HB can be reduced. This can smooth the flow of the hydraulic oil between the connection port CP and the cylinder chamber 21 more effectively.

In a specific example of the above-described one embodiment, the method of manufacturing the cylinder block further includes a step of moving the working tool 60 in a direction not parallel to the first direction DX (axial direction DA) to enlarge the holes HA, HB. According to this specific example, since the inclined surface portion IS formed over a wide range, the flow of the hydraulic oil between the connection port CP and the cylinder chamber 21 can be made smoother more effectively.

While one embodiment has been described with reference to a plurality of specific examples, these specific examples are not intended to limit the embodiment. The above-described embodiment can be implemented in various other specific examples, and various omissions, substitutions, changes, additions, and the like can be made without departing from the scope of the invention.

Claims

1. A cylinder block, wherein,

the cylinder block is provided with a plurality of cylinder portions in a circumferential direction around a rotation axis, and the cylinder portion includes:

2. The cylinder block according to claim 1,

at least a part of the inclined surface portion has a shape constituting a part of a side surface portion of the cone.

3. The cylinder block according to claim 1,

the connection port has a shape exceeding the cylinder chamber in a circumferential direction of the cylinder block.

4. The cylinder block according to claim 1,

5. The cylinder block according to claim 1,

the port wall surface portion has a roughness smaller than that of the inclined surface portion.

6. The cylinder block according to claim 1,

a plurality of inclined surface portions separated from each other are connected to one cylinder wall surface portion.

7. A cylinder block, wherein,

the cylinder block is provided with:

8. A hydraulic device, wherein,

the hydraulic device is provided with the cylinder block according to claim 1 or 7.

9. A construction machine in which, in a construction machine,

the construction machine is provided with the hydraulic device according to claim 8.

10. A method for manufacturing a cylinder block, wherein,

the method for manufacturing the cylinder block comprises the following steps:

a step of advancing a machining tool having a tapered tip portion to one side in a direction to form a hole in a material, the hole including an inclined surface portion inclined with respect to the one direction and opening to the other side in the direction; and

11. A method for manufacturing a cylinder block, wherein,

the method for manufacturing the cylinder block comprises the following steps:

a step of preparing a raw material including a cylinder chamber having one side open in one direction; and

12. The manufacturing method of a cylinder block according to claim 10 or 11,

in the hole forming process, a plurality of holes are formed to be separated from each other.

13. The manufacturing method of a cylinder block according to claim 12,

the method of manufacturing a cylinder block includes a step of moving another machining tool in a direction intersecting the one direction to cut a portion of the raw material located between the plurality of holes so that the inclined surface portion is at least partially left.

14. The manufacturing method of a cylinder block according to claim 13,

the roughness of the surface formed using the other processing tool is smaller than the roughness of the inclined surface portion formed using the processing tool.

15. The manufacturing method of a cylinder block according to claim 10 or 11,

the method of manufacturing a cylinder block includes a step of moving another machining tool in a direction intersecting the one direction to enlarge the hole.