JP2020180601A - Variable displacement hydraulic pump and construction machine - Google Patents

Abstract

To provide a variable displacement hydraulic pump which can detect an inclination angle of a swash plate accurately with a simple structure and achieve downsizing, and to provide a construction machine.SOLUTION: A hydraulic pump 1 according to an embodiment includes: a casing 2 and pistons 21; a swash plate 5; a linkage member 68; and a rotation angle sensor 8. The pistons 21 are provided within the casing 2 and revolve around a center axis C1. The swash plate 5 is provided within the casing 2, autorotates around a rotation axis C2 intersecting with the center axis C1, and restricts movement of the pistons 21 in a direction along the center axis C1. The linkage member 68 outputs a rotation angle of the swash plate 5. The rotation angle sensor 8 detects a position of the linkage member 68.SELECTED DRAWING: Figure 7

Description

The present invention relates to variable displacement hydraulic pumps and construction machinery.

As the variable displacement hydraulic pump, there is a swash plate type variable displacement hydraulic pump (hereinafter, simply referred to as a hydraulic pump) for supplying hydraulic oil to various hydraulic actuators mounted on construction machines such as hydraulic excavators. This type of hydraulic pump has a rotating shaft rotatably supported in the casing and includes a cylinder block that rotates integrally with the rotating shaft. The cylinder block is provided with a plurality of cylinder holes. A piston is inserted in each cylinder hole. A cylinder chamber is formed by a cylinder hole and a piston.

Further, a swash plate having a tilt angle that can be freely changed with respect to the casing is provided at an end opposite to the end on the side where the cylinder chamber of the piston is formed. The rotation axis of the tilt angle of the swash plate is orthogonal to the rotation axis of the cylinder block. The piston slides along the swash plate, and the swash plate regulates the movement of the piston in the cylinder hole. In many cases, a regulator that changes the tilt angle of the swash plate is connected to the swash plate via a lever. The tilt angle of the swash plate is adjusted by the regulator, and the tilt angle of the swash plate is accurately controlled by feeding the tilt angle via the lever.

Under such a configuration, when the piston slides along the swash plate, the piston slides in the cylinder hole. The hydraulic oil is discharged at a predetermined flow rate by utilizing the change in the volume of the cylinder chamber caused by this. That is, the discharge amount of the hydraulic pump changes based on the inclination angle of the swash plate.

Here, various techniques for controlling the discharge amount of the hydraulic pump with high accuracy by detecting the inclination angle of the swash plate are disclosed. For example, there is a technique of detecting the swing angle of a lever connecting the swash plate and the regulator and calculating the tilt angle of the swash plate based on the detection result.

Japanese Unexamined Patent Publication No. 8-189475

By the way, in small construction machines, it is desired to reduce the size of the hydraulic pump. In such a hydraulic pump, the configuration of the regulator may be simplified without providing a lever. In such a case, it is difficult to detect the tilt angle of the swash plate. For example, if an attempt is made to directly detect the inclination angle of the swash plate, a large-scale device such as a stroke sensor is required to improve the detection accuracy, which may increase the manufacturing cost of the hydraulic pump. In addition, the position of the sensor for detecting the tilt angle of the swash plate is restricted, which may increase the size of the hydraulic pump.

The present invention provides a variable displacement hydraulic pump and a construction machine that can accurately detect the tilt angle of a swash plate with a simple structure and can be miniaturized.

The variable displacement hydraulic pump according to one aspect of the present invention includes a casing, a plurality of pistons provided in the casing and revolving around the first rotation axis, and the first rotation axis provided in the casing. A swash plate that rotates around the intersecting second rotation axis and regulates the movement of the plurality of pistons in a direction along the first rotation axis, and a swash plate rotation angle output that outputs the rotation angle of the swash plate. A unit and a sensor for detecting the position of the swash plate rotation angle output unit are provided.

With such a configuration, the movement of the swash plate rotation angle output unit may be detected by the sensor instead of directly detecting the inclination angle of the swash plate by the sensor. Therefore, the manufacturing cost of the variable displacement hydraulic pump can be suppressed with a simple structure without requiring a large-scale sensor. Further, the layout of the sensor can be improved only by changing the shape of the swash plate rotation angle output unit. Therefore, the variable displacement hydraulic pump can be miniaturized.

With the above configuration, the rotation angle of the swash plate may be controlled according to the output of the sensor.

With this configuration, the swash plate can be moved with high accuracy.

In the above configuration, the sensor is a rotation angle sensor, and the rotation angle sensor may be arranged on the second rotation axis.

With such a configuration, the cost of the sensor can be reduced. Further, by arranging the rotation angle sensor on the second rotation axis, the inclination angle of the swash plate can be detected on the second rotation axis. Therefore, the tilt angle of the swash plate can be detected more accurately.

In the above configuration, the sensor is a potentiometer, and one end side of the swash plate rotation angle output unit is rotatably connected to the rotation detection shaft of the potentiometer, and the other end side is rotatably connected to the swash plate. It may be a linkage member.

With this configuration, the variable displacement hydraulic pump can have a simpler structure.

In the above configuration, one of the linkage member and the swash plate may be provided with a protrusion, and either one of the linkage member and the swash plate may be provided with a recess for receiving the protrusion.

With this configuration, the linkage and the swash plate can be easily connected.

In the above configuration, the casing may include an opening, and the sensor may close the opening.

With this configuration, the sensor can be easily attached to the casing.

In the above configuration, the opening may be formed on the second rotation axis.

With this configuration, the sensor can be easily mounted on the second rotation axis. Therefore, it is possible to accurately detect the tilt angle of the swash plate while facilitating the mounting of the sensor.

The construction machine according to another aspect of the present invention includes the above-mentioned variable displacement hydraulic pump and a vehicle body on which the variable displacement hydraulic pump is mounted.

With such a configuration, it is possible to provide a compact construction machine capable of accurately detecting the inclination angle of the swash plate with a simple structure.

The above-mentioned variable displacement hydraulic pump and construction machine have a simple structure, can accurately detect the inclination angle of the swash plate, and can be miniaturized.

The schematic block diagram of the construction machine in embodiment of this invention. FIG. 5 is a cross-sectional view taken along the axial direction of the hydraulic pump according to the embodiment of the present invention. An enlarged perspective view of a part of the hydraulic pump according to the embodiment of the present invention. The perspective view of the swash plate in embodiment of this invention seen from the cylinder block side. The perspective view of the swash plate in embodiment of this invention seen from the front flange side. The perspective view which shows the state which removed the rotation angle sensor from the casing main body in embodiment of this invention. The rotation angle sensor of FIG. 3 and a perspective view which cut out a part around the rotation angle sensor. The explanatory view which shows the procedure of the attachment method of the rotation angle sensor in embodiment of this invention. The explanatory view which shows the procedure of the attachment method of the rotation angle sensor in embodiment of this invention. The explanatory view which shows the procedure of the attachment method of the rotation angle sensor in embodiment of this invention.

Next, an embodiment of the present invention will be described with reference to the drawings.

(Construction machinery)
FIG. 1 is a schematic configuration diagram of the construction machine 100.
As shown in FIG. 1, the construction machine 100 is, for example, a hydraulic excavator. The construction machine 100 includes a swivel body (corresponding to the vehicle body according to the claim) 101 and a traveling body (corresponding to the vehicle body according to the claim) 102. The swivel body 101 is provided on the traveling body 102 so as to be swivelable. The swivel body 101 is provided with a hydraulic pump 1.

The swivel body 101 swings to the cab 103 on which the operator can board, the boom 104 whose one end is swingably connected to the cab 103, and the other end (tip) of the boom 104 on the opposite side of the cab 103. It includes an arm 105 whose one end is freely connected, and a bucket 106 which is swingably connected to the other end (tip) of the arm 105 on the opposite side of the boom 104. Further, a hydraulic pump 1 is provided in the cab 103. The hydraulic oil supplied from the hydraulic pump 1 drives the cab 103, the boom 104, the arm 105, and the bucket 106.

(Hydraulic pump)
FIG. 2 is a cross-sectional view of the hydraulic pump 1. FIG. 3 is an enlarged perspective view of a part of the hydraulic pump 1.
As shown in FIGS. 2 and 3, the hydraulic pump 1 is a so-called swash plate type variable displacement hydraulic pump. The hydraulic pump 1 rotates in the casing 2, the rotating shaft 3 rotatably supported by the casing 2, the cylinder block 4 housed in the casing 2 and fixed to the rotating shaft 3, and the casing 2. A swash plate 5 that controls the discharge amount of hydraulic oil that is freely stored and discharged from the hydraulic pump 1, a first urging portion 6 and a second urging portion 7 that control the rotation angle of the swash plate 5, and a swash plate. It is provided with a rotation angle sensor 8 that detects the rotation angle of 5.
In FIG. 2, the scale of each member is appropriately changed in order to make the explanation easier to understand. Further, in FIG. 3, the illustration of the casing 2 is simplified. Further, in the following description, the direction parallel to the central axis of the rotating shaft 3 (corresponding to the first rotating axis of the claim) C1 is referred to as an axial direction, and the rotational direction of the rotating shaft 3 is referred to as a circumferential direction. The radial direction of is simply referred to as the radial direction.

The casing 2 includes a casing main body 9 having an opening 9a and a front flange 10 that closes the opening 9a of the casing main body 9. The casing main body 9 is provided with a bearing 11 that rotatably supports one end of the rotating shaft 3 on the bottom portion 9b opposite to the opening 9a.

A guide recess 12 for mounting the rotation angle sensor 8 at a position corresponding to the swash plate 5 is formed on the side surface 9c of the casing main body 9. The rotation angle sensor 8 is attached to a predetermined position using the guide recess 12.
A sensor mounting opening (corresponding to the opening according to the claim) 12a for detecting the rotation angle is formed in the guide recess 12. The rotation angle sensor 8 is provided so as to close the sensor mounting opening 12a. The detailed shape and position of the guide recess 12 and the sensor mounting opening 12a will be described later.

Further, on the side surface 9c of the casing main body 9, a first guide portion 49 for guiding the urging rod 46 described later of the second urging portion 7 is provided on the inner surface side. A mounting recess 48 communicating with the first guide portion 49 is formed in the bottom portion 9b of the casing main body 9. An urging pin unit 50, which will be described later, of the second urging portion 7 is attached to the mounting recess 48.
Further, the casing main body 9 is formed with a supply port and a discharge port (not shown). The supply port is connected to a tank (not shown). The discharge port is connected to the cab 103, the boom 104, the arm 105, and the bucket 106 via a control valve or the like (not shown).

The front flange 10 has a swash plate support portion 30 protruding from the inner surface 10a on the casing body 9 side. The swash plate support portion 30 rotatably supports the swash plate 5. The swash plate support portion 30 is formed with a semicircular recess 30a when viewed in the radial direction. The swash plate 5 is brought into contact with the recess 30a.
Further, the front flange 10 is provided with a male screw-shaped stopper 40 on the outer side in the radial direction. A part of the swash plate 5 is brought into contact with the stopper 40 to regulate the rotation angle of the swash plate 5. By turning the stopper 40 with respect to the front flange 10, the amount of protrusion of the stopper 40 from the inner surface 10a side of the front flange 10 changes. As a result, the rotation angle of the swash plate 5 is regulated.

Further, the front flange 10 is formed with a through hole 13 through which the rotating shaft 3 can be inserted. A bearing 14 that rotatably supports the other end side of the rotating shaft 3 is provided in the through hole 13. Further, the through hole 13 is provided with an oil seal 15 on the side opposite to the casing main body 9 (outside the front flange 10) of the bearing 14. The other end of the rotating shaft 3 projects to the outside of the front flange 10 via the bearing 14 and the oil seal 15. The oil seal 15 prevents oil from flowing out from the inside and prevents foreign matter and the like from entering between the front flange 10 and the rotating shaft 3.

A first spline 3a is formed at the other end of the rotating shaft 3 protruding via the oil seal 15. A power source such as an engine (not shown) and a rotating shaft 3 are connected via the first spline 3a. A second spline 3b is formed on the bottom 9b side of the casing main body 9 with respect to the swash plate 5 on the rotating shaft 3, that is, at the center in the axial direction of the rotating shaft 3. The cylinder block 4 is fitted to a portion of the rotating shaft 3 corresponding to the second spline 3b.

The cylinder block 4 is formed in a columnar shape. A through hole 16 into which the rotating shaft 3 can be inserted or press-fitted is formed in the radial center of the cylinder block 4. A spline 16a is also formed in the through hole 16. The spline 16a and the second spline 3b of the rotation shaft 3 are spline-coupled. As a result, the rotating shaft 3 and the cylinder block 4 rotate integrally.

A recess 20 is formed between the center of the through hole 16 in the axial direction and the end portion 4a so as to surround the circumference of the rotating shaft 3. Further, a through hole 25 that penetrates the cylinder block 4 in the axial direction is formed on a part of the inner peripheral surface between the center of the through hole 16 in the axial direction and the side of the swash plate 5. A spring 23 and retainers 24a and 24b, which will be described later, are housed in the recess 20. A connecting member 26, which will be described later, is housed in the through hole 25 so as to be movable in the axial direction.

Further, the cylinder block 4 is formed with a plurality of cylinder holes 17 so as to surround the circumference of the rotating shaft 3. The cylinder holes 17 are arranged at equal intervals along the circumferential direction. Further, the cylinder hole 17 is formed along the axial direction, and the swash plate 5 side is opened. At the end portion 4a of the cylinder block 4 opposite to the front flange 10, a communication hole 18 for communicating the cylinder hole 17 with the outside of the cylinder block 4 is formed at a position corresponding to each cylinder hole 17. ..

The end portion 4a of the cylinder block 4 is provided with a disc-shaped valve plate 19 so as to overlap the end surface of the end portion 4a. The valve plate 19 is fixed to the casing main body 9. The valve plate 19 is stationary with respect to the casing 2 (casing body 9) even when the cylinder block 4 rotates together with the rotating shaft 3.

A supply / discharge port (not shown) communicating with each communication hole 18 of the cylinder block 4 is formed through the valve plate 19 in the thickness direction of the valve plate 19. Each cylinder hole 17 and a supply port and a discharge port (not shown) formed in the casing main body 9 are communicated with each other through the supply / discharge port of the valve plate 19 and the communication hole 18 of the cylinder block 4. Since the valve plate 19 is fixed to the casing main body 9, the cylinder hole 17 is in a state where hydraulic oil is supplied from the supply port via the valve plate 19 and in the discharge port according to the rotation state of the cylinder block 4. The state of discharging hydraulic oil can be switched.

A piston 21 is slidably housed in each cylinder hole 17 along the axial direction. When the piston 21 is housed in the cylinder hole 17, the piston 21 revolves around the central axis C1 of the rotating shaft 3 as the rotating shaft 3 and the cylinder block 4 rotate.
A spherical convex portion 28 is integrally formed at the end portion of the piston 21 on the swash plate 5 side. Further, the inside of the piston 21 is formed in a cavity. This cavity is filled with hydraulic oil in the cylinder hole 17. Therefore, the reciprocating movement of the piston 21 is associated with the supply and discharge of the hydraulic oil to the cylinder hole 17. That is, when the piston 21 is pulled out from the cylinder hole 17, hydraulic oil is supplied into the cylinder hole 17 from the supply port. When the piston 21 enters the cylinder hole 17, hydraulic oil is discharged from the cylinder hole 17 to the discharge port.

The spring 23 housed in the recess 20 of the cylinder block 4 is, for example, a coil spring. The spring 23 is compressed between the two retainers 24a and 24b housed in the recess 20. Therefore, the spring 23 generates an urging force in the direction of extension due to its elastic force. The urging force of the spring 23 is transmitted to the connecting member 26 via the retainer 24b of the two retainers 24a and 24b.
On the front flange 10 side of the connecting member 26, a cylindrical pressing member 27 is provided around the rotating shaft 3. The urging force of the spring 23 received by the connecting member 26 is transmitted to the pressing member 27. The pressing member 27 presses the shoe holding member 29, which will be described later, toward the swash plate 5.

A shoe 22 is attached to a convex portion 28 of each piston 21 housed in each cylinder hole 17 of the cylinder block 4. A spherical concave portion 22a is formed on the surface of the shoe 22 on the side receiving the convex portion 28 so as to correspond to the shape of the convex portion 28. The convex portion 28 of the piston 21 is fitted into the concave portion 22a. As a result, the shoe 22 is rotatably connected to the convex portion 28 of the piston 21.
Each shoe 22 is integrally held by a shoe holding member 29. The shoe holding member 29 is pressed toward the swash plate 5 by the pressing member 27. Further, each shoe 22 is pressed toward the swash plate 5 by the pressing member 27 via the shoe holding member 29.

FIG. 4 is a perspective view of the swash plate 5 as viewed from the cylinder block 4 side. FIG. 5 is a perspective view of the swash plate 5 as viewed from the front flange 10 side.
As shown in FIGS. 1, 4, and 5, the swash plate 5 has a role of restricting the movement of each piston 21 in the axial direction by rotating and tilting. The swash plate 5 has an annular swash plate main body 31 when viewed from the cylinder block 4 side. An insertion hole 32 penetrating in the axial direction is formed at the center of the swash plate body 31 in the radial direction. The rotating shaft 3 is inserted into the insertion hole 32. A flat sliding surface 31a is formed on the cylinder block 4 side of the swash plate main body 31. Each shoe 22 is slidably pressed against the sliding surface 31a.

On the back surface side of the swash plate 31a of the swash plate main body 31, two support convex portions 33, 34 are arranged so as to face each other in the radial direction with the insertion hole 32 as the center. The two support convex portions 33, 34 (first support convex portion 33, second support convex portion 34) are for rotatably supporting the swash plate 5 on the front flange 10. Each of the support convex portions 33, 34 is formed in a semicircular shape when viewed in the radial direction, and has arcuate surfaces 33a, 34a. The support convex portions 33 and 34 are formed so as to project from the swash plate main body 31 so that the arcuate surfaces 33a and 34a face the front flange 10 side.

The arcuate surfaces 33a and 34a of the support convex portions 33 and 34 are slidably contacted with the concave portions 30a of the swash plate support portion 30 projecting from the front flange 10. By sliding the arcuate surfaces 33a and 34a on the recess 30a, the swash plate 5 is rotated with respect to the front flange 10. That is, the rotation axis of the swash plate 5 (corresponding to the second rotation axis of the claim) C2 is orthogonal to the center axis C1 of the rotation axis 3, and the concave portions 30a and the arc centers of the arc surfaces 33a and 34a (see FIG. Is located in. The swash plate 5 rotates about the rotation axis C2.

Of the two support convex portions 33, 34, a pin hole 35 is formed on the radial outer surface 33b of the first support convex portion 33 at substantially the center of the outer surface 33b. A connecting pin (corresponding to the protrusion according to claim) 36 (see FIG. 7) for connecting the linkage member 68 described later is fixed to the pin hole 35 by press fitting or the like. In a state where the connecting pin 36 is fixed to the pin hole 35, the connecting pin 36 projects from the outer surface 33b of the first support convex portion 33 along the rotation axis C2 direction.
Further, on the outer surface 33b of the first support convex portion 33, a guide groove 58 is formed from the end portion on the sliding surface 31a side to the area slightly beyond the pin hole 35. The guide groove 58 is a groove for guiding the linkage member 68 described later to the connecting pin 36.

Further, a first urged portion 37 and a second urged portion 38 facing in the radial direction about the insertion hole 32 are integrally formed on the radial side portion of the swash plate main body 31. The opposite directions of the first urged portion 37 and the second urged portion 38 are orthogonal to the directions in which the two support convex portions 33 and 34 face each other.
The first urging portion 37 extends radially outward from the swash plate main body 31. The first biased portion 37 is formed so as to be slightly tapered toward the outer side in the radial direction. On the radial outer side (tip side) of the first urged portion 37, a connecting recess 39 is formed on a surface (a surface on the cylinder block 4 side) opposite to the protruding direction of each of the supporting convex portions 33 and 34. ing. The first urging portion 6 is connected to the connecting recess 39. The connecting recess 39 is formed in a circular shape when viewed from the axial direction. A round chamfered portion 37a is formed at the tip of the first applied portion 37. The center of the arc of the round chamfered portion 37a substantially coincides with the center of the connecting recess 39.

The second urged portion 38 extends from the swash plate main body 31 toward the side opposite to the first urged portion 37. The second urged portion 38 is formed in a rectangular shape when viewed from the axial direction. In the present embodiment, the surface 38a of the second urged portion 38 on the front flange 10 side is brought into contact with the stopper 40 provided on the front flange 10.
The second urged portion 38 is formed with a contact surface 41 on substantially the entire surface (the surface on the cylinder block 4 side) opposite to the protruding direction of each of the support convex portions 33 and 34. The contact surface 41 is formed by flatly cutting the second urged portion 38. The second urging portion 7 is brought into contact with the contact surface 41.

As shown in FIG. 2, the swash plate 5 configured in this way rotates with respect to the front flange 10, so that the first urged portion 37 and the second urged portion 38 approach the front flange 10. , Tilt to separate. That is, the rotation angle of the swash plate 5 can be said to be the inclination angle of the swash plate 5 with respect to the plane orthogonal to the rotation axis 3.
Here, the rotation angle (tilt angle) of the swash plate 5 refers to the angle formed by the sliding surface 31a and the surface orthogonal to the rotation axis 3. That is, the smaller this angle is, the smaller the rotation angle of the swash plate 5.

As shown in FIG. 2, the first urging portion 6 urges the swash plate 5 in a direction in which the rotation angle of the swash plate 5 increases. The first urging portion 6 includes a first retainer 42 arranged on the bottom 9b side of the casing main body 9, a second retainer 43 arranged on the swash plate 5 side, and a first retainer 42 and a second retainer 43. It includes a first spring 44 and a second spring 45 arranged between them.
A spherical connecting convex portion 43a is formed so as to project on the swash plate 5 side of the second retainer 43. When the connecting convex portion 43a is brought into contact with the connecting concave portion 39 of the swash plate 5, the second retainer 43 is rotatably connected to the swash plate 5.

The first spring 44 is compressed between the first retainer 42 and the second retainer 43. Therefore, the first spring 44 generates an urging force in the direction in which the first spring 44 extends due to its elastic force.
The second spring 45 is arranged inside the first spring 44. Therefore, the outer diameter of the second spring 45 is smaller than the outer diameter of the first spring 44. The second spring 45 is fixed to the second retainer 43.

The second spring 45 is separated from the first retainer 42 when the rotation angle of the swash plate 5 is large (see FIG. 2). As a result, when the rotation angle of the swash plate 5 is large, only the urging force of the first spring 44 acts on the swash plate 5.
On the other hand, when the rotation angle of the swash plate 5 becomes smaller, the second spring 45 comes into contact with the first retainer 42 at a certain rotation angle. Further, when the rotation angle of the swash plate 5 becomes smaller, the second spring 45 is also compressed between the first retainer 42 and the second retainer 43. As a result, the urging forces of both the first spring 44 and the second spring 45 act on the swash plate 5.

In this way, the urging force of the first urging portion 6 can be changed stepwise according to the rotation angle of the swash plate 5. The second spring 45 is not limited to the one fixed to the second retainer 43, and may be fixed to the first retainer 42. Further, it may not be fixed to either the first retainer 42 or the second retainer 43, and may be movable between the first retainer 42 and the second retainer 43.

The second urging portion 7 exerts an urging force on the swash plate 5 in the direction opposite to the urging force of the first urging portion 6 on the swash plate 5. In particular, the second urging portion 7 resists the urging force of the first urging portion 6 in the direction in which the rotation angle of the swash plate 5 increases, and the swash plate 5 in the direction in which the rotation angle of the swash plate 5 decreases. To urge.
The second urging portion 7 includes an urging rod 46 and an urging pin unit 50. The urging pin unit 50 mainly includes a unit case 51 and a plurality of urging pins 52 and 53. Although only two of the plurality of urging pins 52 and 53 are shown in FIG. 2, for example, four of the plurality of urging pins 52 and 53 are provided.

The unit case 51 is mounted so as to be fitted into the mounting recess 48 of the casing main body 9. On the swash plate 5 side of the unit case 51, a plurality of second guide portions 54 for guiding the plurality of urging pins 52 and 53 are provided. The second guide portion 54 is a hole that penetrates the unit case 51 along the axial direction. Further, on the side of the unit case 51 opposite to the swash plate 5, a cylinder hole 55 communicating with one of the plurality of second guide portions 54 is provided. The cylinder hole 55 is opened on the side opposite to the second guide portion 54 of the unit case 51. The opening of the cylinder hole 55 is closed by the cap member 57.

In the cylinder hole 55, a columnar urging piston 56 is arranged so as to be slidable in the axial direction with respect to the cylinder hole 55.
The urging pins 52 and 53 are housed in the second guide portion 54 so as to be slidable in the axial direction. One of the plurality of urging pins 52, 53 is formed longer than the other urging pin 53. One such urging pin 52 is housed in a second guide portion 54 communicating with the cylinder hole 55. The end of one of the urging pins 52 opposite to the swash plate 5 is projected into the cylinder hole 55.

The second guide portion 54 includes, for example, a signal pressure from hydraulic oil discharged from the hydraulic pump 1, a signal pressure from another hydraulic pump driven by the same drive source, or an air conditioner driven by the same drive source. The signal pressure, etc. corresponding to the operation of the external device such as, etc. is input. For example, a signal pressure generated by a control valve or the like is input to the cylinder hole 55. Each urging pin 52, 53 urges the urging rod 46 toward the swash plate 5 according to the signal pressure corresponding to each urging pin 52, 53.

The urging rod 46 is arranged between the contact surface 41 of the swash plate 5 and the urging pins 52 and 53. The urging rod 46 is formed in a columnar shape so as to be long in the axial direction, and is guided so as to be movable in the axial direction by the first guide portion 49 of the casing main body 9.
A spherical surface 46a is formed at the end of the urging rod 46 on the contact surface 41 side. Therefore, even if the angle formed by the swash plate 5 (contact surface 41) and the urging rod 46 changes due to the change in the rotation angle of the swash plate 5, the urging force against the swash plate 5 is applied from the spherical surface 46a. It can be appropriately transmitted to the contact surface 41.

(Guide recess, sensor mounting opening, and rotation angle sensor)
FIG. 6 is a perspective view showing a state in which the rotation angle sensor 8 is removed from the casing main body 9.
As shown in FIG. 6, the guide recess 12 formed in the casing main body 9 is formed in a region including the rotation axis C2. The guide recess 12 is formed in a quadrangular shape when viewed from the direction of the rotation axis C2. Of the four sides of the guide recess 12, two opposing sides are along the axial direction, and the other two opposing sides are orthogonal to the axial direction.

The sensor mounting opening 12a formed in the guide recess 12 is formed on the rotation axis C2. The sensor mounting opening 12a is formed in a quadrangular shape when viewed from the rotation axis C2 direction. The four sides of the sensor mounting opening 12a also follow the same direction as the four sides of the guide recess 12. That is, of the four sides of the sensor mounting opening 12a, the two opposing sides are along the axial direction, and the other two opposing sides are orthogonal to the axial direction.
In the hydraulic pump 1, the rotation axis C2 and the periphery of the rotation axis C2 are exposed through the sensor mounting opening 12a. That is, each part of the cylinder block 4, the swash plate 5, the shoe 22, the shoe holding member 29, and the piston 21 is exposed through the sensor mounting opening 12a.

A slight gap S is formed between the side surface 9c of the casing main body 9 and the outer surface 33b of the first support convex portion 33 on the swash plate 5. Due to this gap S, it is possible to prevent the side surface 9c of the casing main body 9 from interfering with the connecting pin 36 (see FIG. 7) fixed to the first support convex portion 33 of the swash plate 5.
Further, on the side surface 9c of the casing main body 9, female screw portions 60 are formed at positions corresponding to the four corners of the sensor mounting opening 12a. The female screw portion 60 is for fixing the rotation angle sensor 8 to the casing main body 9.

FIG. 7 is a perspective view of the rotation angle sensor 8 of FIG. 3 and a part around the rotation angle sensor 8 cut out.
As shown in FIGS. 3 and 7, the rotation angle sensor 8 is provided so as to close the sensor mounting opening 12a formed on the rotation axis C2 of the swash plate 5 in the casing main body 9. The rotation angle sensor 8 is, for example, a potentiometer (variable resistor). The rotation angle sensor 8 includes a first rotation detection shaft (corresponding to the rotation detection shaft according to the claim) 61, a sensor main body 62 that detects a resistance value according to the rotation angle of the first rotation detection shaft 61, and a sensor main body 62. A base portion 63 for fixing to the side surface 9c of the casing main body 9 is provided. The rotation angle sensor 8 detects a resistance value corresponding to the rotation angle of the first rotation detection shaft 61, and calculates the rotation angle of the first rotation detection shaft 61 based on this resistance value.

The base portion 63 has a plate shape and is formed in a quadrangular shape when viewed from the rotation axis C2 direction. The base portion 63 is formed so as to be larger than the size of the sensor mounting opening 12a of the casing main body 9. The sensor mounting opening 12a is closed by the base portion 63. Bolt insertion holes 63a (see FIG. 8) communicating with the female screw portion 60 of the casing main body 9 are formed at the four corners of the base portion 63. The base portion 63 is fixed to the casing main body 9 by inserting the bolt 64 into the bolt insertion hole 63a and tightening the bolt 64 to the female screw portion 60 of the casing main body 9.

With the base portion 63 fixed to the casing main body 9, the upper surface 63b of the base portion 63 opposite to the casing main body 9 has two support walls 67 rising from both sides along the rotary axis C2 with the rotary axis C2 in between. Is integrally molded. The sensor body 62 is placed and fixed on the two support walls 67.
Further, in a state where the base portion 63 is fixed to the casing main body 9, a cylindrical bearing housing 65 is integrally formed at a position on the base portion 63 through which the rotation axis C2 passes. The bearing housing 65 projects from the base portion 63 toward the swash plate 5. The bearing housing 65 is provided with a flanged bearing 66. The flanged bearing 66 is arranged so that the flange portion 66a abuts on the tip end (end portion on the swash plate 5 side) of the bearing housing 65. The first rotation detection shaft 61 is rotatably supported by the base portion 63 via a flanged bearing 66.

The axis C3 of the first rotation detection shaft 61 coincides with the rotation axis C2. One end 61a on the swash plate 5 side of the first rotation detection shaft 61 projects toward the swash plate 5 from the bearing 66. Further, the other end 61b of the first rotation detection shaft 61 on the sensor body 62 side protrudes toward the sensor body 62 from the support wall 67.

A linkage member 68 is attached to one end 61a of the first rotation detection shaft 61. The linkage member 68 is a plate-shaped member that straddles between one end 61a of the first rotation detection shaft 61 and the connecting pin 36 of the swash plate 5. The thickness direction of the linkage member 68 coincides with the rotation axis C2 direction.
A through hole 69 into which one end 61a of the first rotation detection shaft 61 is inserted is formed on one end 68a side of the first rotation detection shaft 61 side in the longitudinal direction of the linkage member 68. The through hole 69 penetrates in the thickness direction of the linkage member 68.

Here, one end 61a and the through hole 69 of the first rotation detection shaft 61 are formed so that the linkage member 68 does not rotate with respect to the first rotation detection shaft 61. For example, a part of one end 61a is cut flat along the rotation axis C2 (D cut). As a result, the shape of the cross section orthogonal to the rotation axis C2 at one end 61a is made D-shaped. On the other hand, the shape of the through hole 69 is also D-shaped when viewed from the direction of the rotation axis C2 so as to match the shape of one end 61a. By forming the one end 61a and the through hole 69 of the first rotation detection shaft 61 in this way, the rotation of the linkage member 68 with respect to the first rotation detection shaft 61 is prevented.

One end 61a of the first rotation detection shaft 61 projects toward the swash plate 5 side through a through hole 69 of the linkage member 68. A retaining ring or the like (not shown) is attached to the protruding portion. The retaining ring prevents the linkage member 68 from coming off from the first rotation detection shaft 61. Further, the linkage member 68 is sandwiched between a retaining ring (not shown) and a flange portion 66a of a flanged bearing 66 attached to the base portion 63. As a result, the linkage member 68 is non-rotatably connected to the first rotation detection shaft 61.
The means for non-rotatably connecting the linkage member 68 to the first rotation detection shaft 61 is not limited to the above-mentioned D-cut. The linkage member 68 may be non-rotatably connected to the first rotation detection shaft 61. For example, the linkage member 68 may be fixed to the first rotation detection shaft 61 with bolts or the like.

A connecting groove (corresponding to the recess of the claim) 71 is formed at the other end 68b of the linkage member 68 on the connecting pin 36 side. The connecting groove 71 is formed at the center of the linkage member 68 in the lateral direction from the other end 68b to the inside in the longitudinal direction. Further, the connecting groove 71 is formed so as to open on both sides of the linkage member 68 in the thickness direction. As a result, the other end 68b of the linkage member 68 becomes bifurcated. The connecting pin 36 is inserted into the connecting groove 71 formed in this way, and the linkage member 68 is rotatably connected to the connecting pin 36.
Here, the sensor mounting opening 12a formed in the casing main body 9 has a size capable of inserting the linkage member 68 in a state in which the longitudinal direction of the linkage member 68 is oriented in the axial direction (state shown in FIG. 7). Is formed in.

The sensor main body 62 includes a columnar sensor case 72 mounted on two support walls 67 of the base portion 63, and a detection portion 73 provided on the side of the sensor case 72 opposite to the base portion 63. There is.
The sensor case 72 is formed with a convex portion 72a that protrudes toward the base portion 63 side. The sensor case 72 is placed on the support wall 67 so that the convex portion 72a fits between the two support walls 67. The sensor case 72 is fixed on the support wall 67 by bolts 80.

A storage hole 74 is formed on the rotation axis C2 of the sensor case 72 along the rotation axis C2. A coupling 76 connecting the first rotation detection shaft 61 and the detection unit 73 is housed in the storage hole 74. Further, on the side surface of the sensor case 72, a drawer hole 75 that communicates the radial outer side of the sensor case 72 with the storage hole 74 is formed. A sensor wire (not shown) extending from the detection unit 73 is drawn through the drawer hole 75. This sensor line is connected to a control device (not shown).

The detection unit 73 arranged on the sensor case 72 has a second rotation detection shaft (corresponding to the rotation detection shaft of the claim) 77. The second rotation detection shaft 77 is inserted into the storage hole 74 of the sensor case 72. Then, the second rotation detection shaft 77 and the first rotation detection shaft 61 are connected via the coupling 76 housed in the sensor case 72. As a result, the second rotation detection shaft 77 and the first rotation detection shaft 61 rotate integrally. The rotation angle of the second rotation detection shaft 77 is detected by the detection unit 73. The detection result of the detection unit 73 is output as a signal to a control device (not shown) via a sensor line (not shown).
It is desirable that the coupling 76 has a centering function capable of absorbing the misalignment between the second rotation detection shaft 77 and the first rotation detection shaft 61. As a result, the second rotation detection shaft 77 and the first rotation detection shaft 61 can be reasonably connected by the coupling 76.

(How to install the rotation angle sensor)
Next, a method of attaching the rotation angle sensor 8 to the casing main body 9 will be described.
8 to 10 are explanatory views showing a procedure of a method of attaching the rotation angle sensor 8. 8 to 10 correspond to FIG. 7 described above.
Here, in the rotation angle sensor 8, the first rotation detection shaft 61, the sensor body 62, and the base portion 63 are assembled in advance. Further, a linkage member 68 is attached to the first rotation detection shaft 61 of the rotation angle sensor 8. Further, the hydraulic pump 1 is preassembled except for the rotation angle sensor 8.

First, as shown in FIG. 8, a pre-assembled rotation angle sensor 8 is prepared on the sensor mounting opening 12a of the casing main body 9. At this time, the linkage member 68 is directed toward the sensor mounting opening 12a. Further, the position of the linkage member 68 is aligned with the position of the sensor mounting opening 12a.

From this state, as shown in FIG. 9, the rotation angle sensor 8 is lowered toward the sensor mounting opening 12a (see the arrow Y1 in FIG. 9). Then, the base portion 63 of the rotation angle sensor 8 is brought into contact with the side surface 9c of the casing main body 9. In this state, the linkage member 68 has entered the inside of the casing main body 9 via the sensor mounting opening 12a. Further, the rotation axis C2 of the swash plate 5 and the axis C3 of the first rotation detection shaft 61 and the second rotation detection shaft 77 in the rotation angle sensor 8 are deviated from each other. That is, the connecting pin 36 provided in the first support convex portion 33 of the swash plate 5 is not inserted into the connecting groove 71 of the linkage member 68.

The sensor mounting opening 12a is formed in a size capable of inserting the linkage member 68 in a state where the longitudinal direction of the linkage member 68 is oriented in the axial direction (see FIGS. 8 and 9). Therefore, the casing main body 9 and the linkage member 68 do not interfere with each other.
Further, although not shown in FIG. 9, when the rotation angle sensor 8 is lowered toward the sensor mounting opening 12a, one side 12b of the step formed around the guide recess 12 and one side 63c of the base portion 63 ( Both sides 12b and 63c are in contact with each other (see FIG. 3).

Subsequently, as shown in FIG. 10, the rotation angle sensor 8 is slid and moved toward the front flange 10 side (see arrow Y2 in FIG. 10). At this time, the base portion 63 may be slid and moved along one side 12c of the guide recess 12. Here, the guide recess 12 is formed in a quadrangular shape when viewed from the direction of the rotation axis C2. Of the four sides of the guide recess 12, two opposing sides are along the axial direction, and the other two opposing sides are orthogonal to the axial direction. Therefore, the rotation angle sensor 8 can be easily slid in the axial direction along one side 12c of the guide recess 12. As described above, the guide recess 12 serves as a guide for sliding and moving the rotation angle sensor 8 at the time of assembly.

When the rotation angle sensor 8 is slid toward the front flange 10 side, the gap S (see FIG. 6) between the side surface 9c of the casing body 9 and the outer surface 33b of the first support convex portion 33 on the swash plate 5 , The linkage member 68 enters. Then, the connecting pin 36 provided in the first support convex portion 33 is inserted into the connecting groove 71 of the linkage member 68.
At this time, a guide groove 58 is formed on the outer surface 33b of the first support convex portion 33 from the end on the sliding surface 31a side to the area slightly beyond the pin hole 35. The linkage member 68 is guided to the groove 58. Therefore, even if the position of the connecting pin 36 cannot be visually recognized by the casing main body 9, the connecting pin 36 can be easily inserted into the connecting groove 71 of the linkage member 68.

Further, by sliding the rotation angle sensor 8 toward the front flange 10 side, the other side 12c of the step formed around the guide recess 12 and the other side 63d of the base portion 63 are brought into contact with each other. .. As a result, the rotation angle sensor 8 is positioned with respect to the casing main body 9. As described above, the guide recess 12 also has a role of positioning the rotation angle sensor 8 with respect to the casing main body 9.

When the rotation angle sensor 8 is positioned with respect to the casing main body 9, the rotation axis C2 of the swash plate 5 and the axis C3 of the first rotation detection shaft 61 (second rotation detection shaft 77) of the rotation angle sensor 8 are aligned with each other. ..
As a method of aligning the rotation axis C2 and the axis C3, for example, by aligning the female screw portion 60 of the casing main body 9 and the bolt insertion hole 63a of the base portion 63 without forming the guide recess 12. There is a way to do it. Further, the present invention is not limited to these, and it is sufficient that the rotation axis C2 and the axis C3 can be aligned with each other. For example, a positioning convex portion or the like may be provided on the side surface 9c of the casing main body 9, and one side 63d of the base portion 63 may be brought into contact with the convex portion to align the rotation axis C2 and the axis C3. In the state where the rotation axis C2 and the axis C3 are aligned, the sensor mounting opening 12a of the casing main body 9 is closed by the base portion 63.

Subsequently, as shown in FIG. 7, the bolt 64 is inserted into the bolt insertion hole 63a of the base portion 63. Then, the bolt 64 is tightened to the female screw portion 60 of the casing main body 9. As a result, the base portion 63 is fixed to the casing main body 9, and the attachment of the rotation angle sensor 8 to the casing main body 9 is completed.

(Operation of hydraulic pump)
Next, the operation of the hydraulic pump 1 will be described.
The hydraulic pump 1 outputs a driving force based on the discharge of hydraulic oil from the cylinder hole 17 (and the supply of hydraulic oil to the cylinder hole 17).
More specifically, first, by rotating the rotating shaft 3 by the power from a power source such as an engine, the cylinder block 4 is rotated integrally with the rotating shaft 3. As the cylinder block 4 rotates, the piston 21 revolves around the central axis C1 of the rotating shaft 3.

Each shoe 22 attached to the convex portion 28 of each piston 21 is appropriately followed and pressed against the sliding surface 31a of the swash plate 5 by the urging force of the spring 23 regardless of the rotation angle of the swash plate 5. Be done. Further, the convex portion 28 of the piston 21 is formed in a spherical shape, and the concave portion 22a of the shoe 22 into which the convex portion 28 is fitted is also formed in a spherical shape. Therefore, even if the rotation angle of the swash plate 5 changes, each shoe 22 follows the inclination of the swash plate 5 and is appropriately followed and pressed against the sliding surface 31a.

When the piston 21 revolves around the central axis C1 of the rotating shaft 3 with the rotation of the cylinder block 4, each shoe 22 also revolves around the central axis C1 of the rotating shaft 3 on the sliding surface 31a of the swash plate 5. While sliding. As a result, each piston 21 is slid along the axial direction in each cylinder hole 17, and each piston 21 is reciprocated. In this way, the swash plate 5 regulates the movement of each piston 21 in the axial direction. The hydraulic oil is discharged from some of the cylinder holes 17 in response to the reciprocating operation of the piston 21, and the hydraulic oil is sucked into the other cylinder holes 17 to realize a hydraulic pump.

Here, when the rotation angle of the swash plate 5 (sliding surface 31a) changes, the reciprocating stroke (sliding distance) of the piston 21 changes. That is, the larger the rotation angle of the swash plate 5, the larger the supply amount and the discharge amount of the hydraulic oil to the cylinder hole 17 due to the reciprocating movement of each piston 21. On the other hand, the smaller the rotation angle of the swash plate 5, the smaller the supply amount and discharge amount of hydraulic oil to the cylinder hole 17 due to the reciprocating movement of each piston 21. When the rotation angle of the swash plate 5 is 0 degrees, each piston 21 is not reciprocated even if the pistons 21 revolve around the central axis C1 of the rotation shaft 3. Therefore, the amount of hydraulic oil discharged from each cylinder hole 17 is also zero.

Further, the front flange 10 is provided with a male screw-shaped stopper 40 on the outer side in the radial direction. Therefore, as the rotation angle of the swash plate 5 is reduced, the swash plate 5 comes into contact with the stopper 40. The stopper 40 can move forward and backward with respect to the swash plate 5 by rotating it. Therefore, the minimum rotation angle of the swash plate 5 can be appropriately adjusted by moving the stopper 40 forward and backward with respect to the swash plate 5.

Next, the rotational operation of the swash plate 5 will be described.
The swash plate 5 is urged by the first urging portion 6 in a direction in which the rotation angle of the swash plate 5 increases. Further, the swash plate 5 is urged by the second urging portion 7 in a direction in which the rotation angle of the swash plate 5 becomes smaller. The swash plate 5 has the magnitude of the moment around the rotation axis C2 of the swash plate 5 due to the urging force of the first urging portion 6 (counterclockwise moment in FIG. 2, hereinafter simply referred to as counterclockwise moment) and the first. 2 The swash plate 5 is tilted and stopped at a position equal to the magnitude of the moment around the rotation axis C2 of the swash plate 5 (clockwise moment in FIG. 2, hereinafter simply referred to as clockwise moment).

That is, when the clockwise moment by the second urging portion 7 is increased, the rotation angle of the swash plate 5 becomes smaller. By this amount, the first spring 44 and the second spring 45 of the first urging portion 6 are compressed, and the counterclockwise moment by the first urging portion 6 also increases. As a result, the clockwise moment by the second urging unit 7 and the counterclockwise moment by the first urging unit 6 become equal, and the swash plate 5 stops at a predetermined inclination.
On the other hand, when the clockwise moment by the second urging portion 7 is reduced, the urging force of the first spring 44 and the second spring 45 of the first urging portion 6 wins, and the rotation angle of the swash plate 5 becomes large. When the first spring 44 and the second spring 45 are extended along with this, the urging force by the first urging portion 6 becomes smaller. As a result, the clockwise moment by the second urging unit 7 and the counterclockwise moment by the first urging unit 6 become equal, and the swash plate 5 stops at a predetermined inclination.

When changing the clockwise moment by the second urging portion 7, the urging force of the urging rod 46 on the swash plate 5 is changed. That is, for example, the second guide portion 54 of the second urging portion 7 has a signal pressure from the hydraulic oil discharged from the hydraulic pump 1 or a signal pressure from another hydraulic pump driven by the same drive source. , The signal pressure corresponding to the operation of an external device such as an air conditioner driven by the same drive source is input. For example, a signal pressure generated by a control valve or the like is input to the cylinder hole 55. The urging pins 52 and 53 urge the urging rod 46 according to the magnitude of these signal pressures. As a result, the urging force of the urging rod 46 on the swash plate 5 changes.

Here, each signal pressure has a desired rotation angle of the swash plate 5 (amount of hydraulic oil discharged by the hydraulic pump 1) and an actual rotation angle of the swash plate 5 based on an output signal of a control device (not shown). It is controlled so that it does not shift. The output signal of the control device is generated based on the operation signal and the detection signal of the rotation angle of the swash plate 5 by the rotation angle sensor 8. The operation signal includes, for example, an output signal when an operation unit (not shown) of the construction machine 100 (see FIG. 1) is operated.

(Rotation angle sensor detection operation)
Next, the operation of detecting the rotation angle of the swash plate 5 by the rotation angle sensor 8 will be described.
As described above, the swash plate 5 rotates about the rotation axis C2. When the swash plate 5 rotates, the connecting pin 36 attached to the swash plate 5 swings around the rotation axis C2. This swing is transmitted to the linkage member 68 in which the other end 68b is rotatably connected to the connecting pin 36. One end 68a of the linkage member 68 is non-rotatably connected to a first rotation detection shaft 61 located coaxially with the rotation axis C2. Therefore, the linkage member 68 swings about the rotation axis C2 following the connecting pin 36 of the swash plate 5.

Since the first rotation detection shaft 61 to which the linkage member 68 is attached is integrated with the linkage member 68, it rotates as the linkage member 68 swings. The rotation of the first rotation detection shaft 61 is transmitted to the second rotation detection shaft 77 via the coupling 76. As the second rotation detection shaft 77 rotates, the resistance value of the detection unit 73 changes. The rotation angle of the first rotation detection shaft 61 is calculated based on this resistance value. Since the axis C3 of the first rotation detection shaft 61 coincides with the rotation axis C2, the calculated rotation angle of the first rotation detection shaft 61 becomes the rotation angle of the swash plate 5. As a result, the detection of the rotation angle of the swash plate 5 by the rotation angle sensor 8 is completed. A control device (not shown) controls the rotation angle of the swash plate 5 according to the detection result of the rotation angle sensor 8 (output of the rotation angle sensor 8).
It is desirable that the position of the connecting pin 36 is as far as possible from the rotation axis C2. The farther away from the rotation axis C2, the larger the displacement amount of the connecting pin 36 due to the rotation of the swash plate 5. As a result, the swing amount of the linkage member 68 becomes large, so that the accuracy of detecting the rotation angle of the swash plate 5 by the rotation angle sensor 8 can be improved.

As described above, in the above-described embodiment, the swash plate 5 that rotates about the rotation axis C2 in the casing 2, the connecting pin 36 fixed to the swash plate 5, and the rotation that detects the rotation angle of the swash plate 5 are detected. An angle sensor 8 and a linkage member 68 straddling the connecting pin 36 and the first rotation detection shaft 61 of the rotation angle sensor 8 are provided. The rotation of the swash plate 5 is transmitted to the first rotation detection shaft 61 by the linkage member 68. That is, the linkage member 68 has a function of outputting the rotation angle of the swash plate 5 to the first rotation detection shaft 61.
With this configuration, the position (swing angle) of the linkage member 68 may be detected by the rotation angle sensor 8 instead of directly detecting the rotation angle (tilt angle) of the swash plate 5. Therefore, the manufacturing cost of the hydraulic pump 1 can be suppressed with a simple structure without requiring a large-scale sensor. Since the linkage member 68 is a plate-shaped member and has a simple structure, the manufacturing cost of the hydraulic pump 1 can be reduced by this amount.

Further, since the rotation angle of the swash plate 5 is controlled according to the detection result of the rotation angle sensor 8 (output of the rotation angle sensor 8), the swash plate 5 can be moved with high accuracy.
Further, since the rotation of the swash plate 5 is detected via the linkage member 68, the layout of the rotation angle sensor 8 can be improved. Therefore, it is possible to prevent the hydraulic pump 1 from being unnecessarily increased in size, and it is possible to reduce the size.
Moreover, by using the linkage member 68, the axis C3 of the first rotation detection shaft 61 in the rotation angle sensor 8 and the rotation axis C2 of the swash plate 5 can be made to coincide with each other. Since the rotation angle of the swash plate 5 can be detected on the rotation axis C2 of the swash plate 5, the rotation angle of the swash plate 5 can be detected more accurately.

Further, a potentiometer is used as the rotation angle sensor 8. Therefore, the cost of the rotation angle sensor 8 can be reduced as much as possible as compared with the case where an optical sensor or the like is used as the rotation angle sensor 8, for example.
Further, in order to connect the linkage member 68 and the swash plate 5, the connecting pin 36 is fixed to the swash plate 5, and a connecting groove 71 into which the connecting pin 36 is inserted is formed in the other end 68b of the linkage member 68. .. Therefore, the swash plate 5 and the linkage member 68 can be rotatably connected with a simple structure.

Further, when the rotation angle sensor 8 is attached to the casing main body 9, the rotation angle sensor 8 may be slidably moved so as to insert the linkage member 68 into the connecting pin 36. Therefore, the rotation angle sensor 8 can be easily attached to the casing main body 9.
Further, since the guide groove 58 is formed on the outer surface 33b of the first support convex portion 33 in the swash plate 5, the linkage member 68 is guided to the guide groove 58. Therefore, even if the position of the connecting pin 36 cannot be visually recognized by the casing main body 9, the connecting pin 36 can be easily inserted into the connecting groove 71 of the linkage member 68.

Further, a sensor mounting opening 12a is formed on the side surface 9c of the casing main body 9, and the rotation angle sensor 8 is mounted so as to close the sensor mounting opening 12a. With this configuration, the rotation angle sensor 8 with the linkage member 68 attached can be easily assembled to the casing main body 9. The sensor mounting opening 12a can be easily closed by simply mounting the rotation angle sensor 8 on the casing main body 9.
Moreover, by forming the guide recess 12 on the side surface 9c of the casing main body 9, the rotation angle sensor 8 can be easily positioned with respect to the casing main body 9 by using the guide recess 12.

Further, the sensor mounting opening 12a is formed on the rotation axis C2 of the swash plate 5. Therefore, the rotation angle sensor 8 can be easily mounted on the rotation axis C2. As a result, the rotation axis C2 and the axis C3 of the first rotation detection shaft 61 in the rotation angle sensor 8 can be easily aligned. Therefore, the rotation angle of the swash plate 5 can be detected accurately while facilitating the attachment of the rotation angle sensor 8.

The present invention is not limited to the above-described embodiment, and includes various modifications of the above-described embodiment without departing from the spirit of the present invention.
For example, in the above-described embodiment, the case where the construction machine 100 is a hydraulic excavator has been described. However, the present invention is not limited to this, and the above-mentioned hydraulic pump 1 can be adopted in various construction machines.

Further, in the above-described embodiment, the case where the rotation angle sensor 8 is a potentiometer has been described. However, the present invention is not limited to this, and various sensors capable of detecting the rotation angle of the swash plate 5 can be used. However, the swash plate 5 is provided with a member that outputs the rotation angle of the swash plate 5, and the member is configured to be detected by a sensor.
In the present embodiment, the linkage member 68 is provided as a member that outputs the rotation angle of the swash plate 5. For example, when an optical sensor is used as the rotation angle sensor 8, a plate or the like on which an optical pattern is formed may be provided on the swash plate 5 instead of the linkage member 68, and this plate may be detected by the optical sensor. Further, the linkage member 68 may be fixed to an arbitrary position on the swash plate 5 and the position of the linkage member 68 may be detected by a proximity sensor or the like. Even when configured as described above, the same effect as that of the above-described embodiment can be obtained.

Further, in the above-described embodiment, the case where the guide recess 12 and the sensor mounting opening 12a are formed in a quadrangular shape when viewed from the rotation axis C2 direction of the swash plate 5 has been described. However, the shape is not limited to this, and the shapes of the guide recess 12 and the sensor mounting opening 12a can be arbitrarily determined. When the guide recess 12 has a shape other than a quadrangular shape, the positioning of the rotation axis C2 and the axis C3 of the first rotation detection shaft 61 (second rotation detection shaft 77) in the rotation angle sensor 8 is as described above. For example, the female screw portion 60 of the casing main body 9 and the bolt insertion hole 63a of the base portion 63 may be aligned with each other.

Further, in the above-described embodiment, in order to rotatably connect the linkage member 68 to the swash plate 5, a connecting pin 36 is fixed to the swash plate 5, and a connecting groove 71 into which the connecting pin 36 can be inserted into the linkage member 68 is provided. The case where it was formed was described. However, the present invention is not limited to this, and the linkage member 68 may be rotatably connected to the swash plate 5. For example, the connecting pin 36 may be fixed to the linkage member 68, and a recess into which the connecting pin 36 can be inserted may be formed in the swash plate 5. Further, a recess may be formed in the linkage member 68 instead of the connecting groove 71, and a connecting pin 36 fixed to the swash plate 5 may be inserted into the recess. Further, the connecting pin 36 does not have to be, and it may be a protrusion protruding from the swash plate 5 or the linkage member 68.

Further, in the above-described embodiment, the case where the linkage member 68 is a plate-shaped member straddling between one end 61a of the first rotation detection shaft 61 and the connecting pin 36 of the swash plate 5 has been described. However, the shape is not limited to this, and any shape can be used as long as the swash plate 5 and the first rotation detection shaft 61 can be connected to each other.
Further, in the above-described embodiment, the case where the rotation axis C2 of the swash plate 5 is orthogonal to the central axis C1 of the rotation axis 3 has been described. However, it is not necessary that the central axis C1 and the rotation axis C2 are exactly orthogonal to each other. The angle formed by the central axis C1 and the rotating axis C2 may be 90 degrees or more or smaller than 90 degrees.

Further, in the above-described embodiment, the sensor mounting opening 12a formed on the side surface 9c of the casing main body 9 is located on the rotation axis C2 of the swash plate 5, and the first rotation detection shaft 61 of the rotation angle sensor 8 ( The case where the axis C3 of the second rotation detection axis 77) coincides with the rotation axis C2 has been described. However, the present invention is not limited to this, and the sensor mounting opening 12a may be formed at a position deviated from the rotation axis C2 of the casing main body 9. Further, the axis C3 of the first rotation detection shaft 61 (second rotation detection shaft 77) and the rotation axis C2 do not have to coincide with each other. The rotation angle of the swash plate 5 may be detected via the swash plate rotation angle output unit (linkage member 68), and a sensor (rotation angle sensor 8) may be attached to the casing 2.

1 ... Hydraulic pump (variable capacity hydraulic pump), 2 ... Casing, 5 ... Slanted plate, 8 ... Rotation angle sensor (sensor), 9 ... Casing body (casing), 10 ... Front flange (casing), 12a ... Sensor mounting Opening (opening), 21 ... Piston, 36 ... Connecting pin (projection), 61 ... First rotation detection shaft (rotation detection shaft), 63 ... Base, 68 ... Linkage member (slanting plate rotation angle output), 71 ... Connecting groove (recess), 77 ... Second rotation detection shaft (rotation detection shaft), 100 ... Construction machine, 101 ... Swivel body (body), 102 ... Traveling body (body), C1 ... Central axis (first rotation) Axis), C2 ... Rotation axis (second rotation axis)

Claims (8)

Casing and
A plurality of pistons provided in the casing and revolving around the first rotation axis,
A swash plate provided in the casing that rotates about a second rotation axis that intersects the first rotation axis and regulates movement of the plurality of pistons in a direction along the first rotation axis.
A swash plate rotation angle output unit that outputs the rotation angle of the swash plate,
A variable displacement hydraulic pump equipped with a sensor that detects the position of the swash plate rotation angle output unit. The variable displacement hydraulic pump according to claim 1, wherein the rotation angle of the swash plate is controlled according to the output of the sensor. The sensor is a rotation angle sensor.
The variable displacement hydraulic pump according to claim 1 or 2, wherein the rotation angle sensor is arranged on the second rotation axis. The sensor is a potentiometer
Any of claims 1 to 3, the swash plate rotation angle output unit is a linkage member in which one end side is rotatably connected to the rotation detection shaft of the potentialometer and the other end side is rotatably connected to the swash plate. The variable displacement hydraulic pump according to item 1. A protrusion is provided on either one of the linkage member and the swash plate.
The variable displacement hydraulic pump according to claim 4, wherein a recess for receiving the protrusion is provided on either one of the linkage member and the swash plate. The casing has an opening
The variable displacement hydraulic pump according to any one of claims 1 to 5, wherein the sensor closes the opening. The variable displacement hydraulic pump according to claim 6, wherein the opening is formed on the second rotation axis. The variable displacement hydraulic pump according to any one of claims 1 to 7.
A construction machine equipped with a vehicle body equipped with the variable displacement hydraulic pump.

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