KR20190096804A - Hydraulic pump - Google Patents

Abstract

The present invention provides a hydraulic pump which is capable of stable operation while suppressing a size increase. The hydraulic pump (10) comprises: a cylinder block (30) rotating around a rotational axis line A, and having a plurality of cylinder holes (32); a piston (38) retained and supported in each cylinder hole (32) to be slid and moved; a tilted plate (40) which allows the cylinder block (30) to rotate around the rotational axis line A to slide and move each piston (38) in each cylinder hole (32), and is capable of changing a tilting angle thereof; a first pressing means (50) to press the tilted plate (40) in a direction of increasing the tilting angle of the tilted plate (40); and a second pressing means (60) to press the tilted plate (40) in a direction of decreasing the tilting angle of the tilted plate (40). The second pressing means (60) has a pressing rod (61) to press the tilted plate (40), and at least one among a flow control signal pressure and a horsepower shift signal pressure acts on an end surface (61b) of the pressing rod (61) opposite to the tilted plate (40).

Description

Hydraulic Pump {HYDRAULIC PUMP}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to hydraulic pumps for use in construction vehicles and the like, and more particularly to hydraulic pumps of variable displacement type.

Variable displacement type hydraulic pumps are used in a wide range of fields such as construction vehicles. A variable displacement hydraulic pump generally includes a cylinder block formed with a plurality of cylinder holes extending around the axis of rotation and extending in the direction of the axis of rotation, a piston held slidably in each cylinder hole, and the cylinder block being the axis of rotation. It has an inclination plate for sliding each piston in each cylinder hole by rotating around, and the mechanism for changing the inclination angle (tilting angle) of the inclination plate with respect to the rotating shaft of a cylinder block.

For example, Patent Document 1 discloses a variable displacement inclined plate type hydraulic pump whose discharge capacity is adjusted by changing the tilting angle of the inclined plate. The hydraulic pump disclosed in Patent Literature 1 includes a cylinder block rotating around a rotation axis, a piston held slidably in each cylinder hole formed in the cylinder block, an inclined plate configured to change the tilting angle, and tilting of the inclined plate. And a first pressing means for pressing the inclined plate in a direction in which the angle increases, and a second pressing means for pressing the inclined plate in a direction in which the tilting angle of the inclined plate decreases. The second pressing means has a pressure rod and a plurality of pressing pins. Each pressing pin presses the inclined plate through the pressing rod according to the signal pressure corresponding to each pressing pin. According to such a hydraulic pump, there is an advantage that the tilt angle of the inclined plate can be adjusted by a simple mechanism.

Japanese Patent Publication No. 2018-3609

In the technique disclosed in Patent Literature 1, the signal pressure generated by the control valve in response to the lever operation of the operator is input to the second pressure chamber formed in the pressure pin unit. The pressure piston is pressed by the signal pressure input to the second pressure chamber, and the fourth pressure pin is pressed toward the pressure rod by the pressure piston. The present inventors earnestly examined about such a mechanism, and in the hydraulic pump which has such a mechanism, a pressurizing piston unit which has a cross-sectional area larger than the cross-sectional area of a pressurizing pin and a comparatively large component dimension is needed, and the pressurizing pin unit is miniaturized. It was difficult to do so and found that there is a limit in miniaturization and light weight of the entire hydraulic pump.

Moreover, in the technique disclosed by patent document 1, the signal pressure produced | generated by the control valve according to the lever operation of an operator acts on the position shifted radially from the center in the rear end surface of a pressurization rod via the 4th press pin. Due to this, the moment which rotates about the axis line orthogonal to the longitudinal direction of a pressurization rod may generate | occur | produce in the pressurization rod pressurized by the said signal pressure. By this moment, the pressure rod is pushed to the first guide portion to generate a relatively large friction between the pressure rod and the first guide portion. Thereby, there exists a possibility that the operation | movement of a pressurization rod may become unstable because a pressurization rod and a 1st guide part are worn. Further, since friction occurs between the pressure rod and the first guide portion, even though the same signal pressure is input to the second pressure chamber, the position of the pressure rod is different during the movement toward the inclined plate side and the movement toward the opposite side to the inclined plate, There is also a concern that so-called hysteresis may occur. Thereby, there exists a possibility that operation | movement of a pressurization rod may become unstable.

This invention is made | formed in view of such a point, Comprising: It aims at providing the hydraulic pump which can operate stably while suppressing enlargement.

Hydraulic pump according to the present invention,

A cylinder block rotating around a rotation axis, the cylinder block having a plurality of cylinder holes formed therein;

A piston that is slidably held in each cylinder hole,

An inclined plate for sliding each piston in each cylinder hole by rotating the cylinder block around the rotation axis, the inclined plate configured to be able to change its tilting angle;

First pressing means for pressing the inclined plate in a direction in which the tilting angle of the inclined plate increases;

And a second pressing means for pressing the inclined plate in a direction in which the tilting angle of the inclined plate becomes small,

The second pressing means has a pressing rod for pressing the inclined plate,

At least one of a flow control signal pressure and a horsepower shift signal pressure acts on a cross section of the pressure rod opposite to the inclined plate.

In the hydraulic pump of the present invention,

The flow rate control signal pressure may act on the cross section.

In the hydraulic pump of the present invention,

The flow rate control signal pressure may be a negative flow rate control signal pressure.

In the hydraulic pump of the present invention,

The flow control signal pressure or the horsepower shift signal pressure may act on the cross section via an orifice.

In the hydraulic pump of the present invention,

The flow control signal pressure or the horsepower shift signal pressure may act on the cross section via a slow return mechanism.

In the hydraulic pump of the present invention,

The flow rate control signal pressure or the horsepower shift signal pressure may be a signal pressure at which an electric signal is hydraulically converted by an electromagnetic proportional valve.

In the hydraulic pump of the present invention,

A signal pressure having a relatively high pressure among the flow rate control signal pressure and the horsepower shift signal pressure may act on the cross section.

In the hydraulic pump of the present invention,

It further has a guide for guiding the side of the pressing rod,

Pressure oil from another pump may be supplied between the side face and the guide part.

In the hydraulic pump of the present invention,

The guide portion is provided with a supply hole for supplying pressure oil from the other pump between the side surface and the guide portion,

The side surface is provided with an oil holding groove for holding the pressurized oil supplied from the supply hole,

The oil holding groove may face the supply hole at any position during the advancing / removing operation of the guide portion of the pressure rod.

In the hydraulic pump of the present invention,

The second pressing means further has a pressing pin,

The pressing pin may press the inclined plate through the pressing rod in accordance with a signal pressure corresponding to the pressing pin.

Industrial Applicability According to the present invention, a hydraulic pump capable of stable operation while suppressing enlargement can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure for demonstrating one Embodiment by this invention, and is a figure which shows the cross section of a hydraulic pump.
It is a figure which shows the cross section of the pressurizing pin unit of a hydraulic pump, and is a figure which shows the cross section corresponding to the II-II line of FIG.
3 is a diagram illustrating a modification of the hydraulic pump.
4 is a diagram illustrating another modified example of the hydraulic pump.
5 is a view showing still another modification of the hydraulic pump.
6 is a view showing still another modification of the hydraulic pump.
7 is a view showing still another modification of the hydraulic pump.
8 is a view showing still another modification of the hydraulic pump.
It is a figure which shows another modified example of a hydraulic pump, and is a figure which shows the positional relationship of a pressurizing rod and the supply hole of lubricating oil, when a pressurizing rod is located in the opposite side to the inclination plate.
It is a figure which shows the positional relationship of a pressurization rod and a supply hole, when the pressurization rod of FIG. 9 is located in the inclined board side.
11 is a cross-sectional view showing still another modification of the hydraulic pump.
12 is a cross-sectional view showing still another modification of the hydraulic pump.

EMBODIMENT OF THE INVENTION Hereinafter, one Embodiment of this invention is described with reference to drawings. In addition, in the drawing attached to this specification, for convenience of illustration and understanding, the scale, aspect ratio, etc. are changed suitably, and are exaggerated.

In addition, about the terms, such as "parallel", "orthogonal", "identical", the value of length, an angle, etc. which specify the shape and geometrical conditions, and the precision used in this specification, it is bound by a strict meaning. Interpretation should be made to include the extent to which equivalent functions can be expected without work.

1 to 11 are diagrams for describing one embodiment according to the present invention. 1 is a figure which shows the cross section of a hydraulic pump.

The hydraulic pump 10 of this embodiment is a so-called inclined plate type variable displacement hydraulic pump. The hydraulic pump 10 outputs a driving force based on the discharge of the hydraulic oil from the cylinder hole 32 (and supply of the hydraulic oil to the cylinder hole 32) mentioned later. More specifically, by rotating the rotary shaft 25 by the power from a power source such as an engine, the cylinder block 30 coupled to the rotary shaft 25 by spline coupling or the like to rotate, and the rotation of the cylinder block 30 The piston 38 is reciprocated by this. By the reciprocating operation of this piston 38, hydraulic fluid is discharged from some cylinder holes 32, hydraulic oil is sucked into the other cylinder holes 32, and a hydraulic pump is realized.

The hydraulic pump 10 shown in FIG. 1 has a housing 20, a rotating shaft 25, a cylinder block 30, an inclined plate 40, a first pressing means 50 and a second pressing means 60. . Moreover, the gear pump 14 as an example of another pump mentioned later is provided in the hydraulic pump 10 shown in FIG.

The housing 20 has the 1st housing block 21 and the 2nd housing block 22 couple | bonded with the fastening means etc. which are not shown with respect to the 1st housing block 21. As shown in FIG. The housing 20 accommodates a part of the rotating shaft 25, the cylinder block 30, the inclined plate 40, and the first pressing means 50. In the example shown in FIG. 1, an unshown supply port communicated with one end of the rotation shaft 25 and the plurality of cylinder holes 32 via the suction plate 35 inside the first housing block 21. And a discharge port and a first guide part (guide part) 23 for guiding the pressure rod 61 to be described later. In addition, the supply port is provided through the first housing block 21, and communicates with a hydraulic source (tank) provided outside the hydraulic pump 10.

The first housing block 21 is provided with a hole for rotation shaft 24a into which the rotation shaft 25 is inserted, and the rotation shaft 25 is formed around the rotation axis A by the bearing 28a in the hole for rotation shaft 24a. Is rotatably supported. The rotation axis A extends along the longitudinal direction of the rotation shaft 25. One end of the rotary shaft 25 is located in the hole 24a for the rotary shaft, and is connected to the rotary shaft 16 of the gear pump 14 through the spline coupling portion 26a formed at the one end.

The second housing block 22 is provided with a hole for rotation shaft 24b through which the rotation shaft 25 penetrates, and the rotation shaft 25 penetrates the cylinder block 30 and the inclined plate 40 from one end thereof to the other end thereof. It is extended. The rotating shaft 25 is rotatably supported around the rotating axis A by the bearing 28b arrange | positioned at the hole 24b for rotating shafts at the other end. In the illustrated example, the other end of the rotating shaft 25 protrudes outward from the hole 24b for the rotating shaft, and is connected to a power source such as an engine through the spline coupling portion 26b formed at the other end.

In the example shown in FIG. 1, the rotating shaft 25 is spline-coupled with the cylinder block 30 in the spline coupling part 26c provided in the part which penetrates the cylinder block 30. The spline coupling with the cylinder block 30 allows the rotation shaft 25 to move in the direction of the rotation axis A irrespective of the cylinder block 30, but the cylinder block 30 in the rotation direction around the rotation axis A. Rotate integrally with Moreover, the rotating shaft 25 is rotatably supported by the bearing 28a in the 1st housing block 21, and is rotatably supported through the bearing 28b in the 2nd housing block 22, and is inclined board It is not to contact 40. Therefore, the rotating shaft 25 is not hindered by members other than the cylinder block 30, and is rotatably provided with the cylinder block 30 in the rotation direction around the rotation axis A. As shown in FIG.

The gear pump (other pump) 14 is provided in the hydraulic pump 10 of this embodiment. The gear pump 14 is coupled to the first housing block 21 of the hydraulic pump 10 on the opposite side of the second housing block 22 along the rotation axis A by fastening means or the like not shown. In the example shown in FIG. 1, the gear pump 14 has a rotating shaft 16. The rotating shaft 16 is arrange | positioned rotatably around the rotating axis A. As shown in FIG. That is, the rotating shaft 25 and the rotating shaft 16 share the rotating axis A. As shown in FIG. As described above, one end of the rotation shaft 25 is connected to the rotation shaft 16 of the gear pump 14 through the spline coupling portion 26a formed at the one end. Specifically, one end of the rotating shaft 25 and the sleeve 18 are connected via the spline coupling portion 26a, and the rotating shaft 16 and the sleeve 18 are formed on the rotating shaft 16 with the spline coupling portion 17a. Connected via

When the rotating shaft 25 connected to the power source such as the engine rotates by the driving force from the power source, the rotating shaft 25 and the rotating shaft 16 rotate integrally around the rotating axis A. As shown in FIG. As a result, the hydraulic oil is supplied from the gear pump 14 to the respective parts of the hydraulic pump 10 and the work machine in which the gear pump 14 is built, at a constant pressure. In particular, in the present embodiment, as will be described later, the pressure oil discharged from the gear pump 14 is provided between the side surface 61c of the pressure rod 61 and the first guide portion 23 that guides the side surface 61c. Some are supplied via the supply line L. In addition, since the gear pump 14 can be comprised equivalently to a well-known gear pump, the description about the specific structure is abbreviate | omitted.

The cylinder block 30 rotates about the rotation axis A together with the rotation axis 25, and has a plurality of cylinder holes 32 provided in a periphery around the rotation axis A. FIG. In particular, in the example shown in FIG. 1, each cylinder hole 32 is provided so that it may extend along the direction parallel to rotation axis A, respectively. In addition, it is not limited to this, The cylinder hole 32 may be provided so that it may extend along the direction inclined with respect to the rotation axis A. As shown in FIG. The number of the plurality of cylinder holes 32 formed in the cylinder block 30 is not particularly limited, but these cylinder holes 32 are equally spaced on the same circumference (equal intervals) when viewed from the direction along the rotation axis A. FIG. It is preferable to arrange in).

The opening 32a which communicates with each of the some cylinder hole 32 is formed in the edge part on the opposite side to the side in which the inclination board 40 is provided among the cylinder blocks 30. As shown in FIG. Moreover, the suction and absorption plate 35 in which the some through-hole not shown is formed in the cylinder block 30 facing the edge part on the opposite side to the side in which the inclination plate 40 is provided is arrange | positioned. The plurality of cylinder holes 32 communicate with supply ports and discharge ports, not shown, provided in the first housing block 21 through these openings 32a and through holes, and through these supply ports and discharge ports, Supply and discharge are performed. In addition, in the example shown in FIG. 1, the spring 44 and retainers 45a and 45b which are mentioned later around the rotating shaft 25 of the edge part on the opposite side to the side in which the inclination plate 40 is provided among the cylinder blocks 30 are mentioned. The recessed part 30a which accommodates is formed.

The suction and absorption plate 35 shown in FIG. 1 is fixed to the first housing block 21, and even when the cylinder block 30 rotates together with the rotation shaft 25, the housing 20 (the first housing block 21). Is stopped for). Therefore, the cylinder hole 32 which communicates with each of the supply port and the discharge port is switched through the intake and drain plate 35 in accordance with the rotational state of the cylinder block 30, so that the operating oil is supplied from the supply port and the discharge port. The condition of discharging the hydraulic oil comes up repeatedly.

The piston 38 is arrange | positioned so that sliding to the corresponding cylinder hole 32, respectively is possible. In other words, the piston 38 is held in the corresponding cylinder hole 32 so as to be slidable. In particular, each piston 38 is provided so as to be reciprocated along a direction parallel to the rotation axis A with respect to the corresponding cylinder hole 32. The inside of the piston 38 is a cavity and is filled with hydraulic oil in the cylinder hole 32. The reciprocation of the piston 38 is thus associated with the supply and discharge of hydraulic oil to the cylinder bore 32, so that when the piston 38 is withdrawn from the cylinder bore 32 the hydraulic oil is supplied from the supply port into the cylinder bore 32. When the piston 38 enters the cylinder hole 32, the hydraulic oil is discharged from the cylinder hole 32 to the discharge port.

In this embodiment, the shoe 43 is provided in the edge part (end part of the side which protrudes from the cylinder hole 32) of the inclination plate 40 side of each piston 38. As shown in FIG. Moreover, the spring 44, the retainers 45a and 45b, the connection member 46, the press member 47, and the shoe holding member 48 are provided around the rotating shaft 25. As shown in FIG. The spring 44 and the retainers 45a and 45b are accommodated in the recessed part 30a formed around the rotating shaft 25 of the edge part on the opposite side to the side in which the inclined plate 40 is provided among the cylinder blocks 30. As shown in FIG. . In the example shown in FIG. 1, the spring 44 is a coil spring and is arrange | positioned in the compressed state between the retainer 45a and the retainer 45b in the recessed part 30a. Therefore, the spring 44 generates the pressing force in the direction in which the spring 44 is extended by the elastic force. The pressing force of the spring 44 is transmitted to the pressing member 47 through the retainer 45b and the connecting member 46. Each shoe 43 is held by the shoe holding member 48, and the pressing member 47 receives the pressing force of the spring 44 to guide each shoe 43 through the shoe holding member 48. To 40).

In the example shown in FIG. 1, the inclined plate 40 can be tilted at various angles. However, due to the pressing force of the spring 44, each shoe 43 is attached to the inclined plate 40 regardless of the tilting angle of the inclined plate 40. It follows suitably and press-contacts. Thereby, when the piston 38 rotates with the cylinder block 30, each shoe 43 will slide on the inclined board 40 like a circular track. Moreover, in the example shown, the edge part of the inclination plate 40 side of the piston 38 forms a spherical convex part, the convex part of the piston 38 fits in the spherical concave part formed in the shoe 43, and the shoe 43 The recessed part of the () is caulked, and the spherical bearing structure is formed by the piston 38 and the shoe 43. By this spherical bearing structure, even if the tilting angle of the inclined plate 40 changes, each shoe 43 can follow the tilting of the inclined plate 40 and can slide and rotate on the inclined plate 40 appropriately.

The inclined plate 40 is for sliding each piston 38 in each cylinder hole 32 by rotating the cylinder block 30 around the rotation axis A. As shown in FIG. The inclined plate 40 has a sliding surface 41 that is flat on the side facing the cylinder block 30, and the sliding surface 41 has a shoe 43 connected to an end portion of the piston 38 on the inclined plate 40 side. ) Is in pressure contact. In addition, the inclined plate 40 is provided to be tiltable, and the stroke of the reciprocating motion of the piston 38 changes according to the tilting angle of the inclined plate 40 (sliding surface 41). That is, the larger the tilting angle of the inclined plate 40 (sliding surface 41), the greater the amount and amount of hydraulic oil supplied to the cylinder hole 32 accompanying the reciprocating motion of each piston 38, and the inclined plate 40 (sliding surface) The smaller the tilting angle of (41) is, the smaller the supply amount and discharge amount of the hydraulic oil to the cylinder hole 32 accompanying the reciprocating motion of each piston 38 is. Here, the tilting angle of the inclined plate 40 (sliding surface 41) means the angle which the plate surface (sliding surface 41) of the inclined plate 40 makes with respect to the imaginary plane orthogonal to the rotation axis A. As shown in FIG. When the tilting angle is 0 degrees, even if the cylinder block 30 rotates around the rotation axis A, the respective pistons 38 do not reciprocate, and the amount of hydraulic oil discharged from each cylinder hole 32 also becomes zero. In addition, in the example shown in FIG. 1, the inclination plate 40 is made to contact the stopper 27 provided in the 2nd housing block 22, if the tilting angle is made small. The stopper 27 is comprised with respect to the inclination board 40 so that advancement and retreat are possible. Thereby, the minimum tilting angle of the inclination plate 40 can be adjusted suitably by advancing and stopping the stopper 27 with respect to the inclination plate 40. Moreover, the inclination plate 40 has the contact surface 42 which the pressurizing rod 61 mentioned later contact | abuts on the outer side of the sliding surface 41, and receives a pressing force from the pressure rod 61. As shown in FIG. In the example shown, the contact surface 42 is provided in parallel with the sliding surface 41.

The first pressing means 50 presses the inclined plate 40 in the direction in which the tilting angle of the inclined plate 40 increases. In the example shown in FIG. 1, the 1st pressing means 50 is the 1st retainer 51 arrange | positioned on the opposite side to the inclination plate 40 (the 1st housing block 21 side), and the inclination plate 40 side ( 2nd retainer 52 arrange | positioned at the 2nd housing block 22 side), and the spring 54 and 55 arrange | positioned between the 1st retainer 51 and the 2nd retainer 52. As shown in FIG. The first spring 54 is arranged in a compressed state between the first retainer 51 and the second retainer 52. Therefore, the first spring 54 generates the pressing force in the direction in which the first spring 54 is extended by the elastic force. The second spring 55 is disposed inside the first spring 54. For this reason, the winding diameter of the 2nd spring 55 is formed smaller than the winding diameter of the 1st spring 54. As shown in FIG.

In the example shown in FIG. 1, the second spring 55 is fixed to the second retainer 52, and from the first retainer 51 in a state where the tilt angle of the inclined plate 40 is large (see FIG. 1). Are spaced apart. As a result, while the tilting angle of the inclined plate 40 is large, only the pressing force of the first spring 54 acts on the inclined plate 40. When the tilting angle of the inclined plate 40 decreases, the second spring 55 contacts the first retainer 51 at any tilting angle. In addition, when the tilting angle of the inclined plate 40 decreases, the second spring 55 is also compressed between the first retainer 51 and the second retainer 52, whereby the inclined plate 40 has a first spring 54. ) And the pressing force on both sides of the second spring 55 act. Therefore, according to the illustrated first pressing means 50, the pressing force can be changed in steps according to the tilting angle of the inclined plate 40. In addition, the second spring 55 is not limited to being fixed to the second retainer 52, and may be fixed to the first retainer 51, and to any one of the first retainer 51 and the second retainer 52. It is also possible to move between the first retainer 51 and the second retainer 52 without being fixed. In the illustrated example, the separation distance of the first retainer 51 with respect to the second retainer 52 can be adjusted by advancing the adjuster 57 toward the first retainer 51. Thereby, the initial pressing force of the 1st pressing means 50, especially the initial pressing force of the 1st pressing means 50 by the 1st spring 54 can be adjusted suitably.

The second pressurizing means 60 causes the inclined plate 40 to apply a pressing force in a direction opposite to that of the inclined plate 40 by the first pressurizing means 50. In particular, the second pressing means 60 resists the pressing force in the direction in which the tilting angle of the inclined plate 40 by the first pressing means 50 increases, and the inclined plate (in the direction in which the tilting angle of the inclined plate 40 decreases) Press 40). In the example shown in FIG. 1, the second pressing means 60 has a pressing rod 61 and a pressing pin unit 70. The pressure rod 61 is pressed toward the inclined plate 40 in accordance with the signal pressure P input (introduced) to the first pressure chamber 81 formed between the pressure rod 61 and the pressure pin unit 70, and the inclined plate Tilt 40 around its tilting axis. The pressure pin unit 70 has a unit case 76 and a plurality of first pressure pins 71. Each 1st press pin 71 presses the press rod 61 toward the inclination board 40 according to the signal pressure corresponding to each 1st press pin 71. In other words, each of the first pressing pins 71 presses the inclined plate 40 through the pressing rod 61 according to the signal pressure corresponding to each of the first pressing pins 71.

In the example shown in FIG. 1, the pressure rod 61 has a generally cylindrical shape as a whole, and the contact surface 42 of the inclined plate 40 and the pressure pin unit are arranged so that their axes are parallel to the rotation axis A. FIG. It is arrange | positioned between each 1st press pin 71 of 70. In addition, the pressure rod 61 is not limited to what was arrange | positioned so that the axis line may become parallel to the rotation axis A, and the axis line may be arrange | positioned inclined with respect to the rotation axis A. FIG. The pressurizing rod 61 is a front end surface 61a facing the inclined plate 40 (butting surface 42), and a rear end surface (cross section) that forms the opposite side to the front end surface 61a along the axis of the pressure rod 61. ) 61b and the side surface 61c which connects the front end surface 61a and the rear end surface 61b. In the example shown, the front end surface 61a is spherical. Thereby, even if the angle which the inclination plate 40 (contact surface 42) and the pressing rod 61 makes due to the change of the tilting angle of the inclination plate 40 changes, the pressing force with respect to the inclination plate 40 is selected. It can transmit from the end surface 61a to the contact surface 42 suitably. In addition, the rear end surface 61b of the pressure rod 61 has a flat surface orthogonal to the axis line of the pressure rod 61. In addition, the rear end surface 61b should just have a shape which can function as an action surface on which the signal pressure P acts, and the specific shape is not specifically limited. The rear end surface 61b may have a flat surface inclined with respect to the axis line of the pressure rod 61, and may include a curved surface. For example, the rear end surface 61b has a spherical shape projecting from the pressure rod 61, a spherical shape concave toward the pressure rod 61, a wave shape, a shape in which a plurality of flat surfaces are combined, and a shape in which a plurality of curved surfaces are combined. Or a shape including a flat surface and a curved surface, a shape including a stepped portion, or the like.

The 1st housing block 21 (housing 20) is provided with the 1st guide part (guide part) 23 for guiding the side surface 61c of the pressure rod 61, The pressure rod 61 is It is arrange | positioned so that a sliding movement with respect to the 1st guide part 23 is possible. For this reason, the pressurizing rod 61 is hold | maintained so that a part of it may slide in the 1st guide part 23. As shown in FIG. The 1st guide part 23 is comprised from the through-hole provided in the 1st housing block 21, and has a cross-sectional shape which forms a cross-sectional shape and complementary shape of the pressing rod 61. As shown in FIG. That is, the 1st guide part 23 is comprised by the cylindrical through hole which has a circular cross section. In the example shown in FIG. 1, the 1st guide part 23 is provided integrally with the 1st housing block 21 (housing 20). When the first guide portion 23 is provided integrally with the first housing block 21, the first guide portion 23 can be formed by drilling in the first housing block 21, and the first guide portion 23 can be formed by simple processing. It is possible to form the guide portion 23. In addition, since no additional member is required to provide the first guide portion 23, it contributes to the reduction of the number of parts of the hydraulic pump 10 and the cost. In addition, the structure of the 1st guide part 23 is not limited to this. As an example, the first guide portion 23 formed by using a cylindrical member different from the first housing block 21, for example, may be provided in the housing 20.

In the first housing block 21 (housing 20), a recess 29 is formed in communication with the first guide portion 23, and the recess 29 is a convex portion of the pressing pin unit 70. Part 78 is fitted.

When pressing the inclined plate 40 with the pressure rod 61, when a force in a direction inclined with respect to the axial direction of the pressure rod 61 acts on the pressure rod 61 by the reaction force from the inclined plate 40. There is. Since the hydraulic pump 10 of this embodiment has the 1st guide part 23 mentioned above, even if the force of the direction which inclines with respect to the axial direction of the pressure rod 61 acts on the pressure rod 61, Since the 1st guide part 23 can hold | maintain the pressure rod 61 suitably, the pressure rod 61 can be operated stably.

In the example shown in FIG. 1, pressure oil from another pump is supplied between the side surface 61c of the pressure rod 61 and the first guide portion 23. In the illustrated example, as another pump, a gear pump 14 installed in the hydraulic pump 10 is used. The hydraulic oil is supplied from the gear pump 14 through the supply line L and into the first guide portion 23. As an example, the supply line L may be a passage opening through the gear pump 14 and the housing 20 (the first housing block 21) to the first guide portion 23. In addition, the other pump may be a hydraulic pump arrange | positioned independently from the hydraulic pump 10, and hydraulic pumps other than a gear pump may be sufficient as it.

The hydraulic oil supplied from another pump functions as a lubricating oil which reduces the frictional resistance between the side surface 61c and the first guide portion 23. In the technique disclosed in Patent Literature 1, oil held in the housing or in the recess of the first housing block is supplied to the side of the pressure rod, whereby lubrication is performed between the side of the pressure rod and the first guide portion. . In this embodiment, since the pressure oil discharged from another pump is forcibly supplied between the side surface 61c and the first guide portion 23 at a predetermined pressure, more effectively between the side surface 61c and the first guide portion 23. Can be lubricated. In particular, in the technique disclosed in Patent Literature 1, when the pressure rod starts to move, the pressure rod does not move even if the pressure force by the pressure pin starts to be generated, and the pressure rod suddenly becomes short after the pressure force by the pressure pin becomes a certain size. There was a case where it started moving. Thereby, there exists a possibility that the tilting angle of a swash plate may change rapidly and it may become impossible to stably discharge pressure oil by a hydraulic pump. In contrast, in the present embodiment, the pressurized rod 61 can be smoothly moved by forcibly supplying the pressurized oil discharged from another pump at a predetermined pressure between the side surface 61c and the first guide portion 23. Discharge of the pressurized oil by the hydraulic pump 10 can be performed stably.

Moreover, in the technique disclosed by patent document 1, the pressing force by each press pin acts on the position shifted in the radial direction from the center in the rear end surface of a press rod. Due to this, the moment which rotates about the axis line orthogonal to the longitudinal direction of a pressurization rod may generate | occur | produce in the pressurization rod pressurized by the said pressing force. By this moment, the pressure rod is pushed to the first guide portion to generate a relatively large friction between the pressure rod and the first guide portion. Thereby, even if the same signal pressure is input to the 1st pressure chamber and the 2nd pressure chamber, what is called a hysteresis in which the position of a pressurization rod differs in the movement toward an inclined plate side, and a movement toward an opposite side to an inclined plate also arises. have. In contrast, in the present embodiment, the pressure oil discharged from the other pump is forcibly supplied between the side surface 61c and the first guide portion 23 at a predetermined pressure, so that the side surface 61c and the first side of the pressure rod 61 are made. The friction which may arise between the 1 guide part 23 can be reduced, and generation | occurrence | production of the hysteresis with respect to the position of the pressurizing rod 61 can be suppressed.

The oil holding groove 65 for holding the pressurized oil supplied from another pump is provided in the side surface 61c of the pressurization rod 61. As shown in FIG. In the example shown in FIG. 1, the oil retaining groove 65 has a predetermined width in the longitudinal direction (axial direction) of the pressure rod 61, has a predetermined depth in the radial direction, and is along the side surface 61c. It is formed over the whole periphery of the circumferential direction. In other words, the pressure rod 61 has a diameter smaller than the diameter of the small diameter portion adjacent to the distal end side (the distal end surface 61a side) of the small diameter portion along the longitudinal direction and the small diameter portion relatively thinned. It has a 1st large diameter part which has, and a 2nd large diameter part which has a diameter larger than the diameter of a small diameter part adjacent to the rear end side (rear end surface 61b side) of a small diameter part along a longitudinal direction. In the illustrated example, the diameter of the first large diameter portion and the diameter of the second large diameter portion are the same. The depth along the radial direction of the oil holding groove 65 can be 0.5 mm or more and 1.5 mm or less as an example. Since the pressurizing rod 61 has such an oil holding groove 65, a cylindrical gap is formed between the pressurizing rod 61 and the first guide part 23, so that the pressurized oil supplied from another pump is supplied to the gap. It becomes possible to maintain. Thereby, lubricating oil can be supplied stably and uniformly between the 1st large diameter part and the 1st guide part 23 from the oil holding groove 65, and between the 2nd large diameter part and the 1st guide part 23. FIG. . Therefore, the pressure rod 61 can be operated stably and smoothly. In addition, the specific shape of the oil holding groove 65 is not limited to the shape shown in FIG.

The surface of the pressure rod 61 may be surface-treated in order to suppress abrasion of the pressure rod 61 and the like. When surface treatment is performed on the front end surface 61a of the pressure rod 61, the frictional resistance between the front end surface 61a and the contact surface 42 of the inclined plate 40 is reduced to make contact with the front end surface 61a. Wear of the surface 42 can be suppressed. When the surface treatment is applied to the side surface 61c of the pressure rod 61, the frictional resistance between the side surface 61c and the first guide portion 23 is reduced to wear down the side surface 61c and the first guide portion 23. Can be suppressed. Moreover, when surface treatment is given to the rear end surface 61b of the pressure rod 61, the abrasion of the rear end surface 61b and the 1st pressing pin 71 and the adjustment pin 73 which contact | connects the said rear end surface 61b is suppressed. can do. Such surface treatment can be performed by forming an amorphous carbon film on the surface of the pressure rod 61, for example.

The first pressure chamber 81 is formed between the pressure rod 61 and the pressure pin unit 70. More specifically, the space located between the rear end face 61b of the pressure rod 61 and the pressure pin unit 70 is the first pressure chamber 81. The signal pressure P which is at least one of a flow control signal pressure and a horsepower shift signal pressure is input into the 1st pressure chamber 81. As a result, the signal pressure P acts on the rear end surface 61b of the pressure rod 61. In particular, the signal pressure P directly acts on the rear end surface 61b of the pressure rod 61. Here, "directly acting" means that the signal pressure P acts on the rear end surface 61b of the pressing rod 61 without passing through another member such as a pressing pin, for example.

The flow control signal pressure is a signal pressure generated in response to a lever operation by an operator operating a work machine or the like in which the hydraulic pump 10 is incorporated. More specifically, the flow control signal pressure is a signal pressure generated corresponding to the operation of the control valve according to the lever operation by the operator. For example, in the negative flow control (negative control) mechanism, an orifice is provided between the control valve and the tank in the center bypass line that goes from the variable displacement hydraulic pump to the tank via the control valve. The leakage flow rate of the hydraulic oil passing through the orifice is detected as the back pressure of the orifice, and the detected back pressure is fed back to the variable displacement hydraulic pump as the negative flow control signal pressure. As one example, this negative flow control signal pressure can be input to the first pressure chamber 81 as the flow control signal pressure.

It is also possible to use the load sensing signal flow control signal pressure as the flow control signal pressure. When the flow rate decrease signal pressure from the load sensing flow rate control mechanism is input into the first pressure chamber 81, the pressure rod 61 is pressed toward the inclined plate 40 side, and the tilting angle of the inclined plate 40 becomes small. As a result, the amount of pressure oil discharged from the hydraulic pump 10 decreases.

The horsepower shift signal pressure is a signal pressure for decreasing (shifting) the maximum discharge flow rate of the hydraulic oil from the hydraulic pump 10. For example, when using a work machine or the like in which the hydraulic pump 10 is built in a place with high elevation, the driving force output from a power source such as an engine is lowered because the amount of oxygen contained in the atmosphere is small. In this state, when the tilting angle of the inclined plate 40 is maximized to discharge the pressurized oil from the hydraulic pump 10 at the maximum discharge flow rate, the power source may be loaded with high load. In order to prevent this, in the place with high elevation, the horsepower shift signal pressure is input to the 1st pressure chamber 81, the maximum tilt angle of the inclination plate 40 is shifted small, and the maximum discharge flow volume of the hydraulic oil from the hydraulic pump 10 is reduced. Can be reduced.

Only one of the flow rate control signal pressure and the horsepower shift signal pressure may be input to the first pressure chamber 81, or both of the flow rate control signal pressure and the horsepower shift signal pressure may be input to the first pressure chamber 81. .

As described above, by allowing at least one of the flow control signal pressure and the horsepower shift signal pressure to act on the rear end surface 61b of the pressure rod 61, the pressure piston having a relatively large component size can be omitted in the technique disclosed in Patent Document 1. In this way, the enlargement of the hydraulic pump 10 can be effectively suppressed.

As described above, in the technique disclosed in Patent Literature 1, the position where the signal pressure generated by the control valve in accordance with the lever operation of the operator is shifted in the radial direction from the center in the rear end face of the pressure rod via the fourth pressure pin. Act on Due to this, the moment which rotates about the axis line orthogonal to the longitudinal direction of a pressurization rod may generate | occur | produce in the pressurization rod pressurized by the said signal pressure. By this moment, the pressure rod is pushed to the first guide portion to generate a relatively large friction between the pressure rod and the first guide portion. Thereby, there exists a possibility that the operation | movement of a pressurization rod may become unstable by abrasion of a pressurization rod and a 1st guide part. Further, since friction occurs between the pressure rod and the first guide portion, even though the same signal pressure is input to the second pressure chamber, the position of the pressure rod is different during the movement toward the inclined plate side and the movement toward the opposite side to the inclined plate, There is also a concern that so-called hysteresis may occur. Thereby, there exists a possibility that operation | movement of a pressurization rod may become unstable. In contrast, in the present embodiment, at least one of the flow control signal pressure and the horsepower shift signal pressure acts on the entire rear end surface 61b of the pressure rod 61, and the circumference of the axis perpendicular to the longitudinal direction of the pressure rod 61 is perpendicular. It is possible to effectively suppress the generation of the moment of rotation. Therefore, the wear of the pressure rod 61 and the first guide part 23 and the occurrence of hysteresis with respect to the position of the pressure rod 61 can be suppressed. That is, it becomes possible to provide stability to the operation of the hydraulic pump 10.

In addition, since the area of the rear end surface 61b of the pressure rod 61 is sufficiently large compared with the cross-sectional area of the first pressure pin 71, even when a relatively small signal pressure is input to the first pressure chamber 81, the pressure is applied. The pressurizing rod 61 can exert sufficient pressing force in order to change the tilting angle of the inclined plate 40 without using a piston.

Next, the specific structure of the pressurizing pin unit 70 is demonstrated with reference to FIG. 1 and FIG. FIG. 2 shows a cross section corresponding to the II-II line in FIG. 1. In the illustrated example, the pressing pin unit 70 has a plurality of first pressing pins 71, an adjusting pin 73, an adjuster 77, and a unit case 76. Each 1st press pin 71 presses the inclination board 40 through the press rod 61 according to the signal pressure corresponding to each 1st press pin 71.

In the example shown in FIGS. 1 and 2, the first pressing pin 71 has a generally cylindrical shape as a whole, and the axis thereof is parallel to the axis of the pressing rod 61 so that It is arrange | positioned on the opposite side to the inclination plate 40. In the example shown especially, the 1st press pin 71 is arrange | positioned so that the axis line may become in parallel with the rotation axis A. FIG. The front end surface of the first pressing pin 71 that faces the pressing rod 61 has a flat surface. Moreover, it is not limited to this, The front end surface of the 1st pressing pin 71 may have shapes other than flat surface, such as spherical shape.

The unit case 76 is provided with a plurality of second guide portions 75 for guiding the side surfaces of the first pressing pin 71, and each of the first pressing pins 71 has a second guide portion 75. It is arrange | positioned so that sliding is possible with respect to. For this reason, each 1st press pin 71 is hold | maintained so that sliding at least one part in the corresponding 2nd guide part 75 is possible. Each 2nd guide part 75 is comprised from the hole provided in the unit case 76, and has a cross-sectional shape which forms a cross-sectional shape and the complementary shape of the 1st pressing pin 71. As shown in FIG. That is, each 2nd guide part 75 is comprised by the cylindrical hole which has a circular cross section. Moreover, in the 2nd guide part 75, the 2nd pressure chamber 82 which receives the signal pressure with respect to the 1st press pin 71 is formed in the opposite side to the press rod 61 of the 1st press pin 71, have.

In the example shown in FIGS. 1 and 2, the second guide portion 75 is provided integrally with the unit case 76. When the second guide portion 75 is provided integrally with the unit case 76, each second guide portion 75 can be formed by drilling the unit case 76, and the second guide portion 75 can be formed by simple processing. 75) can be formed. In addition, since no additional member is required to provide the second guide portion 75, it contributes to the reduction of the number of parts and the cost of the hydraulic pump 10. In addition, the structure of the 2nd guide part 75 is not limited to this. As an example, you may make it install the 2nd guide part 75 different from the unit case 76, for example using the cylindrical member in the unit case 76. As shown in FIG.

The adjustment pin 73 is a member for adjusting the position of the pressure rod 61 when the pressure rod 61 is pushed in the opposite side to the inclined plate 40. Therefore, the adjustment pin 73 is able to adjust the position in the longitudinal direction by the adjuster 77. In the example shown in FIG. 1, the adjuster 77 consists of a set screw and a nut. The unit case 76 includes a rear chamber 89 in which a surface on the side opposite to the pressure rod 61 in the unit case 76 and an end portion on the side opposite to the pressure rod 61 of the adjustment pin 73 are accommodated. The through-hole to connect is formed, and the fixing screw of the adjuster 77 is screwed with this through-hole. Therefore, the position in the longitudinal direction of the adjustment pin 73 can be adjusted by rotating a fixing screw and changing the position with respect to the through-hole of a fixing screw.

On the housing 20 side (pressure rod 61 side) of the unit case 76, it has the convex part 78 formed so that the 1st press pin 71 may be enclosed. The convex portion 78 is fitted into the concave portion 29 provided in the first housing block 21 (housing 20). As shown in FIG. 2, the convex portion 78 has a circular cross section. In addition, the concave portion 29 of the first housing block 21 also has a circular cross-sectional shape corresponding to the cross-sectional shape of the convex portion 78.

If the 1st pressing pin 71 is comprised so that the pressing rod 61 may be pressed toward the inclination board 40 according to the signal pressure corresponding to each 1st pressing pin 71, the specific shape and arrangement will be specifically made. Although it is not limited, As an example, each 1st pressing pin 71 can be made into the shape and arrangement as demonstrated below with reference to FIG. 2 mainly.

In the example shown in FIG. 2, each of the first pressing pin 71 and the adjusting pin 73 is viewed in the axial direction of each of the first pressing pin 71 and the adjusting pin 73, that is, the pressing rod 61. In the axial direction of), all have a circular cross section having the same diameter. According to the first pressing pin 71 and the adjusting pin 73 having such a shape, for example, each of the first pressing pin 71 and the adjusting pin 73 can be manufactured by cutting a single long bar. Can be. It is also possible to form the plurality of second guide portions 75 by drilling the same diameter. Thereby, the manufacturing process of each 1st press pin 71, the adjustment pin 73, and each 2nd guide part 75 can be simplified.

In addition, in the example shown, each 1st pressing pin 71 is arrange | positioned so that the center (axis line) may be located on one circumference C as seen from the axial direction of each 1st pressing pin 71. As shown in FIG. In particular, each 1st pressing pin 71 is arrange | positioned at equal intervals along one circumference C. As shown in FIG. In other words, the center angles in the center of the circumference C by the two first pressing pins 71 adjacent to one circumference C are all equal. In the example shown, all the center angles in the center of the said circumference C by the two 1st press pin 71 which adjoin on one circumference C are 90 degrees. Moreover, in the example shown, the center (axis line) of each 1st press pin 71 is arrange | positioned in the area | region which overlaps the press rod 61, as seen from the axial direction of each 1st press pin 71. As shown in FIG. Moreover, in the example shown, the whole of each 1st pressing pin 71 is arrange | positioned in the area | region which overlaps with the pressing rod 61, as seen from the axial direction of each 1st pressing pin 71. As shown in FIG. By arranging the first pressing pin 71 in this manner, the pressing pin unit 70 can be effectively miniaturized.

In the example shown in FIG. 1 and FIG. 2, the press rod 61, each 1st press pin 71, and the adjustment pin 73 are formed with the solid member. If the pressure rod 61 and the pins 71 and 73 are formed with a solid member, the pressure rod 61 and the pins 71 and 73 can be manufactured by a relatively simple process, and the pressure rod 61 and Sufficient mechanical strength can be given to the pins 71 and 73. Therefore, it is possible to effectively prevent the deformation of the pressure rod 61 and the pins 71 and 73 while miniaturizing the pressure rod 61 and the pins 71 and 73, thereby extremely tilting the tilt plate 40. It can be performed stably.

Moreover, the groove | channel or notch through which oil can flow may be provided in the side surface of the adjustment pin 73 from the one end to the other end. As an example, a notch may make a part of side surface chamfer so that the cross section orthogonal to the longitudinal direction of the adjustment pin 73 may become substantially D-shape. For example, when oil flows into the rear chamber 89 from the first pressure chamber 81 through the gap between the adjustment pin 73 and the unit case 76, the position of the adjustment pin 73 is changed by the presence of the oil. There is a possibility that the pressure rod 61 is shifted. On the other hand, if the groove or notch is provided in the side surface of the adjustment pin 73, when the adjustment pin 73 is pressed by the pressure rod 61, the oil which flowed into the rear chamber 89 will pass through this groove or notch. It is possible to quickly return to the first pressure chamber 81. Therefore, it is possible to improve the positional accuracy of the pressure rod 61 when the pressure rod 61 is pushed in the opposite side to the inclined plate 40.

In each second pressure chamber 82 corresponding to each of the first pressurizing pins 71, for example, a signal pressure by hydraulic oil discharged from the hydraulic pump 10 or a signal from another hydraulic pump driven by the same drive source. The pressure or the signal pressure corresponding to the operation of an external device such as an air conditioner driven by the same drive source is input. When the hydraulic pump 10 is a so-called split flow hydraulic pump having the function of two pumps as one pump, the signal pressure by the two hydraulic fluids discharged from the hydraulic pump 10 is different from each other. Input can be made to pin 71.

Therefore, each 1st press pin 71 is an external apparatus, such as the signal pressure by the hydraulic oil discharged from the hydraulic pump 10, the signal pressure from the other hydraulic pump driven by the same drive source, or the air conditioner driven by the same drive source. It is driven by the signal pressure corresponding to the operation of the. Thereby, each 1st press pin 71 presses the press rod 61 toward the inclination plate 40, respectively.

Next, the tilting operation of the inclined plate 40 will be described. The rotating shaft 25 of the hydraulic pump 10 is driven by a drive source, such as a diesel engine, for example. The drive source stalls when a load greater than the drive force of the drive source is applied to this drive source. Therefore, it is necessary to control the operation of the hydraulic pump 10 so that the load on the drive source is equal to or less than the drive force of the drive source. In a hydraulic device, a plurality of hydraulic pumps may be driven by one drive source. In this case, it is preferable to control the operation of the hydraulic pump 10 so that the total driving force of the plurality of hydraulic pumps driven by one drive source is equal to or less than the drive force of the drive source. When an external device such as an air conditioner is driven by the same drive source, it is preferable to control the operation of the hydraulic pump 10 in consideration of the load on the drive source by the external device.

When the operator operating the hydraulic device does not operate the operation lever, the hydraulic actuator driven by the hydraulic oil discharged from the hydraulic pump does not operate. In addition, when the operator operates the operation lever at a shallow angle (fine operation), the hydraulic actuator operates slowly (non-operation). In these cases, the hydraulic actuator needs only a small amount of hydraulic oil from the hydraulic pump, and hydraulic oil not used for driving the hydraulic actuator has conventionally been discharged to a recovery tank or the like. In this case, however, most of the driving force of the hydraulic pump is wasted, and waste is also generated in fuel consumed from a driving source such as a diesel engine for driving the hydraulic pump. In the past, so-called high-grade hydraulic equipment had a function of reducing the discharge amount of the hydraulic oil of the hydraulic pump at the time of non-operation and non-operation of the hydraulic actuator. However, in the inexpensive hydraulic equipment, such a function has not been realized. Therefore, it is desired to realize the function of reducing the discharge amount of the hydraulic oil of the hydraulic pump at the time of non-operation and non-operation of the hydraulic actuator by a simple mechanism.

Here, the negative flow rate control signal pressure is input to the first pressure chamber 81, and the hydraulic oil discharged from the hydraulic pump 10 is respectively supplied to the second pressure chamber 82 corresponding to each of the first pressure pins 71. An example in which the signal pressure corresponding to the signal pressure, the signal pressure from another hydraulic pump driven by the same drive source, and the signal pressure corresponding to the operation of the air conditioner driven by the same drive source are input will be described.

In addition, the 1st pressing pin 71 corresponding to the 2nd pressure chamber 82 to which a signal pressure is not input can be used as a spare pressing pin. When such a preliminary pressurizing pin is provided, when the hydraulic pump 10 is to be controlled in consideration of the operation of the hydraulic pump or an external device by adding another hydraulic pump or an external device, By inputting a signal pressure into the 2nd pressure chamber 82 corresponding to a spare pressure pin, this spare pressure pin can be used as a pressure pin corresponding to the said hydraulic pump or external equipment. Therefore, it is possible to flexibly cope with the addition of other hydraulic pumps or external equipment, and the versatility of the hydraulic pump 10 can be effectively improved.

The inclined plate 40 is pressed in the direction in which the tilting angle of the inclined plate 40 is increased by the first pressing means 50, and is pressed in the direction in which the tilting angle of the inclined plate 40 is decreased by the second pressing means 60. do. The inclined plate 40 has a magnitude of a moment (a counterclockwise moment in FIG. 1) around the tilting axis of the inclined plate 40 due to the pressing force of the first pressing means 50, and the second pressing means 60. The tilting stops at a position where the magnitude of the moment (the clockwise moment in FIG. 1) around the tilting axis of the inclined plate 40 becomes equal.

In the example described here, the flow rate control signal pressure is input to the first pressure chamber 81. Specifically, the back pressure of the orifice in the center bypass line of the negative flow control mechanism is detected, and the detected back pressure is input to the first pressure chamber 81 as the negative flow control signal pressure. The flow control signal pressure input to the first pressure chamber 81 acts on the rear end surface 61b of the pressure rod 61. In particular, the flow control signal pressure input to the first pressure chamber 81 urges the rear end surface 61b of the pressure rod 61.

In order to deactivate or deactivate the hydraulic actuator, by operating the control valve in the negative flow control mechanism, the flow rate of the pressure oil directed to the hydraulic actuator via the control valve is reduced. That is, the flow rate of the pressurized oil returned to the tank through the center bypass line increases. An orifice is provided between the control valve and the tank in the center bypass line. When the flow rate of the pressurized oil passing through the center bypass line increases, the pressure (back pressure) of the pressurized oil at the front of the orifice of the center bypass line is increased. Is increased. By inputting this back pressure into the 1st pressure chamber 81 as a negative flow control signal pressure, this signal pressure acts on the rear end surface 61b of the pressure rod 61, and the pressure rod 61 is the inclined plate 40 ( It is pressed toward the contact surface 42.

The signal pressure by the hydraulic oil discharged from the hydraulic pump 10 is input to the second pressure chamber 82 corresponding to one first pressing pin 71 of the plurality of first pressing pins 71. For example, when the flow path of the hydraulic oil discharged from the hydraulic pump 10 branches and is connected to the 2nd pressure chamber 82, the signal pressure by the hydraulic oil discharged from the hydraulic pump 10 becomes the 1st press pin 71 Is input to the second pressure chamber 82 corresponding to. When the load of the hydraulic actuator driven by the hydraulic oil discharged from the hydraulic pump 10 becomes large, the pressure of the hydraulic oil discharged from the hydraulic pump 10 becomes large. That is, the signal pressure by the hydraulic oil discharged from the hydraulic pump 10 becomes large. The first pressure pin 71 is pressed toward the pressure rod 61 by this signal pressure. Therefore, the 1st press pin 71 presses the inclination board 40 (contact surface 42) through the press rod 61. As shown in FIG.

The signal pressure from another hydraulic pump driven by the same drive source is input to the second pressure chamber 82 corresponding to the other first pressure pin 71. For example, when the flow path of the hydraulic oil discharged from another hydraulic pump branches and is connected to the 2nd pressure chamber 82, the signal pressure by the hydraulic oil discharged from the said hydraulic pump corresponds to the 1st press pin 71 2 is input to the pressure chamber 82. When the load of the hydraulic actuator driven by the hydraulic oil discharged from another hydraulic pump becomes large, the pressure of the hydraulic oil discharged from the said hydraulic pump becomes large. That is, the signal pressure by the hydraulic oil discharged from another hydraulic pump becomes large. The first pressure pin 71 is pressed toward the pressure rod 61 by this signal pressure. Therefore, the 1st press pin 71 presses the inclination board 40 (contact surface 42) through the press rod 61. As shown in FIG.

The signal pressure corresponding to the operation of the air conditioner driven by the same drive source is input to the second pressure chamber 82 corresponding to the first pressure pin 71. For example, the other hydraulic circuit is branched and connected to the second pressure chamber 82 corresponding to the first press pin 71. In addition, a valve such as a solenoid valve (magnetic valve) is provided in the flow path of the hydraulic oil between the branch branched from the hydraulic circuit and the second pressure chamber 82. While the air conditioner is not operating, the oil flow path is closed by a valve. When the air conditioner is operated, the valve receives the signal (electric signal) to operate the valve to open the oil flow path. As a result, no signal pressure is input to the second pressure chamber 82 corresponding to the first pressure pin 71 while the air conditioner is not operating. Signal pressure is input from the hydraulic circuit. The first pressure pin 71 is pressed toward the pressure rod 61 by this signal pressure. Therefore, the 1st press pin 71 presses the inclination board 40 (contact surface 42) through the press rod 61. As shown in FIG.

The pressing force for pressing the pressure rod 61 to the inclined plate 40 (abutment surface 42), that is, the pressing force to the inclined plate 40 by the second pressing means 60 is determined by the first pressing pin 71. The sum of the pressing forces on the pressure rod 61 is obtained. The moment around the tilting axis of the inclined plate 40 due to the pressing force of the second pressing means 60 (the moment in the clockwise direction in FIG. 1) is the tilting axis of the inclined plate 40 due to the pressing force of the first pressing means 50. When larger than the surrounding moment (the counterclockwise moment in FIG. 1), the inclined plate 40 is tilted so that its tilting angle becomes smaller, and the tilting plate 40 is tilted around the tilting axis of the inclined plate 40 due to the pressing force of the second pressing means 60. When the moment and the moment around the tilting axis of the inclined plate 40 due to the pressing force of the first pressing means 50 are balanced, the inclined plate 40 stops tilting. As a result, the flow rate of the hydraulic oil discharged from the hydraulic pump 10 decreases.

In the hydraulic pump 10 of the present embodiment, the operator does not operate or finely manipulates the operation lever, or the load of the hydraulic actuator driven by the hydraulic oil discharged from the hydraulic pump 10 is increased, or by the same drive source. When the load of the other hydraulic pump to be driven is increased, or when the external device such as an air conditioner driven by the same drive source is adapted to at least one of operating, the pressing force of the second pressurizing means 60 is increased, and the inclined plate 40 ) Is tilted so that the tilting angle is small, so that the flow rate of the hydraulic oil discharged from the hydraulic pump 10 is reduced. Thereby, generation | occurrence | production of the stall of the drive source, such as a diesel engine which drives the hydraulic pump 10, can be prevented effectively. In addition, the waste of fuel consumed at the driving source can be reduced, and the energy saving efficiency of the hydraulic equipment including the hydraulic pump 10 can be effectively improved.

The hydraulic pump 10 of this embodiment is the cylinder block 30 which rotates around the rotation axis A, the cylinder block 30 in which the several cylinder hole 32 extended along the rotation axis A direction was formed, and each The piston 38 slidably held in the cylinder hole 32 and the cylinder block 30 rotate about the rotation axis A to slide each piston 38 in each cylinder hole 32. The inclined plate 40, the inclined plate 40 configured to be able to change the tilting angle, the first pressing means 50 for pressing the inclined plate 40 in a direction in which the tilting angle of the inclined plate 40 increases, and the inclined plate 40 Has a second pressurizing means 60 for pressurizing the inclined plate 40 in a direction in which the tilting angle of the) decreases, and the second pressurizing means 60 has a pressurizing rod 61 for pressurizing the inclined plate 40, Flow control signal pressure and horsepower are provided on the rear end surface 61b on the opposite side to the inclined plate 40 in the pressure rod 61. And at least one act of soft signal pressure.

According to the hydraulic pump 10, at least one of the flow control signal pressure and the horsepower shift signal pressure acts on the rear end surface 61b of the pressure rod 61, so that the pressure piston having a relatively large component size can be omitted. Therefore, the enlargement of the hydraulic pump 10 can be suppressed effectively.

Moreover, according to such a hydraulic pump 10, the flow control signal pressure and / or the horsepower shift signal pressure act on the whole of the rear end surface 61b of the pressurization rod 61, and the longitudinal direction of the pressurization rod 61 is carried out. It is possible to effectively suppress the generation of the moment of rotation about the axis perpendicular to the axis. Therefore, the wear of the pressure rod 61 and the first guide part 23 and the occurrence of hysteresis with respect to the position of the pressure rod 61 can be suppressed. That is, the hydraulic pump 10 can be operated stably.

In the hydraulic pump 10 of this embodiment, the flow control signal pressure acts on the rear end surface 61b.

In the hydraulic pump 10 of the present embodiment, the flow control signal pressure is a negative flow control signal pressure.

According to the hydraulic pump 10 as described above, the pressing force of the second pressurizing means 60 is increased when the hydraulic actuator is inactive and non-operating, and the inclined plate 40 is tilted so that its tilting angle becomes smaller. The flow rate of the hydraulic oil discharged from the 10 is reduced. Thereby, generation | occurrence | production of the stall of the drive source, such as a diesel engine which drives the hydraulic pump 10, can be prevented effectively. In addition, the waste of fuel consumed at the driving source can be reduced, and the energy saving efficiency of the hydraulic equipment including the hydraulic pump 10 can be effectively improved. The flow control signal pressure may be a load sensing flow control signal pressure.

The hydraulic pump 10 of this embodiment has a guide part 23 which guides the side surface 61c of the pressurizing rod 61 further, and the pressure from the other pump is provided between the side surface 61c and the guide part 23. Oil is supplied.

According to such a hydraulic pump 10, it is possible to smoothly move the pressure rod 61 by forcibly supplying the pressurized oil discharged from another pump to a predetermined pressure between the side surface 61c and the first guide portion 23. It is possible to stably discharge the pressurized oil by the hydraulic pump 10 and to reduce the friction that may occur between the side surface 61c of the pressurizing rod 61 and the first guide portion 23 to pressurize it. The occurrence of hysteresis with respect to the position of the rod 61 can be suppressed.

In the hydraulic pump 10 of this embodiment, the 2nd pressurizing means 60 further has a pressurizing pin 71, and the pressurizing pin 71 is a pressurizing rod (according to the signal pressure corresponding to the pressurizing pin 71). The inclination plate 40 is pressed through 61.

According to such a hydraulic pump 10, in addition to the flow control signal pressure and / or the horsepower shift signal pressure acting on the rear end surface 61b of the pressure rod 61, the signal pressure by the hydraulic oil discharged from the hydraulic pump 10 The pressure rod 61 can be pressed toward the inclined plate 40 also by other signal pressures such as signal pressures from other hydraulic pumps driven by the same drive source and signal pressures corresponding to the operation of air conditioners driven by the same drive source. . In other words, the flow rate of the pressure oil discharged from the hydraulic pump 10 can be controlled based on the signal pressure other than the flow rate control signal pressure and / or the horsepower shift signal pressure. Therefore, it becomes possible to control the flow volume of the pressurized oil discharged from the hydraulic pump 10 with a higher degree of freedom.

In addition, it is possible to make various changes with respect to embodiment mentioned above. Hereinafter, the modification is demonstrated, referring drawings suitably. In the following description and the drawings used in the following description, the same reference numerals as those used for the corresponding portions in the above-described embodiments are used for the parts that can be configured equivalent to the above-described embodiments. , Duplicate descriptions are omitted.

FIG. 3: is a figure which shows one modification of the hydraulic pump 10, and is a figure for demonstrating the signal pressure P input into the 1st pressure chamber 81 of the hydraulic pump 10. As shown in FIG. In the example shown in FIG. 3, the signal pressure P which is at least one of the flow control signal pressure and the horsepower shift signal pressure is input to the first pressure chamber 81 through the orifice 91. That is, the signal pressure P acts on the rear end surface 61b of the pressure rod 61 through the orifice 91.

When the hydraulic pump, the control valve and each actuator constitute a closed hydraulic circuit (closed circuit), the signal pressure P is inputted in that the hydraulic oil is input to the first pressure chamber via these hydraulic pumps, the control valve and each actuator. May oscillate. When the signal pressure P oscillates, the operation of the pressure rod becomes unstable, whereby the flow rate of the pressurized oil discharged from the hydraulic pump also becomes unstable. On the other hand, in the hydraulic pump 10 of this modification, the amplitude can be made small by the orifice 91, and signal pressure P can be input to a 1st pressure chamber. Therefore, it is possible to stabilize the operation of the pressure rod and the flow rate of the pressurized oil discharged from the hydraulic pump.

FIG. 4: is a figure which shows the other modified example of the hydraulic pump 10, and is a figure for demonstrating the signal pressure P input into the 1st pressure chamber 81 of the hydraulic pump 10. As shown in FIG. In the example shown in FIG. 4, the signal pressure P which is at least one of the flow control signal pressure and the horsepower shift signal pressure is input to the first pressure chamber 81 through the slow return mechanism 93. That is, the signal pressure P acts on the rear end surface 61b of the pressure rod 61 through the slow return mechanism 93.

The slow return mechanism 93 has an orifice 94 and a check valve 95 connected in parallel with each other. The check valve 95 of this modification is comprised so that the oil pressure which flows out from the 1st pressure chamber 81 may pass, but the oil pressure which flows into the 1st pressure chamber 81 will not pass. In addition, it is not limited to this, The check valve 95 may be comprised so that the hydraulic oil which flows in into the 1st pressure chamber 81 may pass, but the hydraulic oil which flows out from the 1st pressure chamber 81 may become impossible to pass.

According to this modification, the slow return function can be added to the hydraulic pump 10. In particular, in the illustrated example, when the tilting angle of the inclined plate 40 is increased by the flow increase signal from the control valve to increase the flow rate of the pressurized oil discharged from the hydraulic pump 10, that is, the inclined plate 61 is rotated. When it moves to the opposite side to 40, the pressure oil in the 1st pressure chamber 81 flows out quickly through the check valve 95 of the slow return mechanism 93, and the inclination plate ( When the tilting angle of 40 is reduced to reduce the flow rate of the pressurized oil discharged from the hydraulic pump 10, that is, when the pressurizing rod 61 is moved to the inclined plate 40 side, the pressurized oil of the slow return mechanism 93 It passes through the orifice 94 and slowly flows into the first pressure chamber 81.

FIG. 5: is a figure which shows the further another modification of the hydraulic pump 10, and is a figure for demonstrating the signal pressure P input into the 1st pressure chamber 81 of the hydraulic pump 10. As shown in FIG. In the example shown in FIG. 5, the signal pressure P which is at least one of the flow control signal pressure and the horsepower shift signal pressure is generated by converting the electric signal into hydraulic pressure by the electromagnetic proportional valve 97.

In the illustrated example, the pressure oil from the oil supply source S passes through the electromagnetic proportional valve 97 and is input into the first pressure chamber 81 as the signal pressure P. The electromagnetic proportional valve 97 receives a signal for flow rate control and / or a horsepower shift as an electric signal, and adjusts the opening degree of the oil pressure flow path from the oil supply source S in accordance with this electric signal.

According to this modification, since the signal for the flow rate control and / or the horsepower shift can be handled as an electrical signal, the hydraulic piping can be reduced, and further miniaturization of the hydraulic pump 10 can be achieved.

FIG. 6: is a figure which shows the further another modification of the hydraulic pump 10, and is a figure for demonstrating the signal pressure P input into the 1st pressure chamber 81 of the hydraulic pump 10. As shown in FIG. In the example shown in FIG. 6, both the flow control signal pressure P1 and the horsepower shift signal pressure P2 pass through the shuttle valve 99 and are input to the first pressure chamber 81. In the shuttle valve 99, only the signal pressure having a relatively high pressure among the two input signal pressures P1 and P2 is allowed to pass, and the signal pressure having a relatively low pressure among the two input signal pressures P1 and P2 is input. It is impossible to pass. Only the signal pressures P1 and P2 passing through the shuttle valve 99 are input to the first pressure chamber 81 as the signal pressure P. As shown in FIG. That is, the signal pressure P is a signal pressure having a relatively high pressure among the flow control signal pressure and the horsepower shift signal pressure.

According to the present modification, a signal pressure having a relatively high pressure among the flow rate control signal pressure P1 and the horsepower shift signal pressure P2 can be selectively input to the first pressure chamber 81.

As another modification, as shown in FIG. 7, the signal pressure P which has passed through the shuttle valve 99 may also be input to the first pressure chamber 81 through the orifice 91. 8, the signal pressure P which passed the shuttle valve 99 may also be input to the 1st pressure chamber 81 through the slow return mechanism 93. Moreover, as shown in FIG.

9 and 10 are diagrams showing still another modification of the hydraulic pump 10, and are views showing the positional relationship between the pressure rod 61 and the supply hole 68 of the lubricating oil. In particular, FIG. 9: is a figure which shows the positional relationship of the pressurizing rod 61 and the supply hole 68 of lubricating oil, when the pressurizing rod 61 is located in the most opposite side to the inclination plate 40, FIG. It is a figure which shows the positional relationship of the pressurizing rod 61 and the supply hole 68 when the pressurizing rod 61 is located in the side of the inclined board 40 most.

In the example shown in FIG. 9 and FIG. 10, a supply hole 68 for supplying pressure oil from another pump to the guide portion 23 between the side surface 61c of the pressure rod 61 and the guide portion 23. This is provided. As shown in FIG. 9, the supply hole 68 faces the oil holding groove 65 of the pressure rod 61 when the pressure rod 61 is located on the opposite side to the inclined plate 40. In addition, as shown in FIG. 10, the supply hole 68 faces the oil holding groove 65 of the pressure rod 61 even when the pressure rod 61 is located on the inclined plate 40 side. That is, the supply hole 68 faces the oil holding groove 65 at any position during the advancing / removing operation along the guide portion 23 of the pressure rod 61. In other words, the oil retaining groove 65 faces the supply hole 68 at any position during the retraction operation along the guide portion 23 of the pressure rod 61.

According to such a hydraulic pump 10, the supply hole 68 and the oil holding groove 65 can communicate with each other even if the pressurizing rod 61 is in any position during the advancement / retraction operation. That is, the hydraulic oil from another pump can always be supplied into the oil holding groove 65. Therefore, lubrication between the side surface 61c of the pressurizing rod 61 and the guide part 23 can be performed stably.

11 is a cross-sectional view showing still another modification of the hydraulic pump 10. The hydraulic pump 10 of this modification is a so-called split flow structure hydraulic pump having the function of two pumps as one pump, and two signal pressures Pa and Pb by the hydraulic oil discharged from the hydraulic pump 10 are Is output.

In the illustrated example, the pressing pin unit 70 has a second pressing pin 72, an adjuster 77, and a unit case 76. The second pressing pin 72 has a large diameter portion having a relatively large diameter and a small diameter portion having a relatively small diameter adjacent to the opposite side to the pressing rod 61 with respect to the large diameter portion. Both the large diameter portion and the small diameter portion are formed in a cylindrical shape, and have a circular cross section when viewed along the longitudinal direction of the second pressing pin 72. The central axis of the cylinder forming the large diameter portion coincides with the central axis of the cylinder forming the small diameter portion. Moreover, the large diameter part and the small diameter part are formed integrally.

The 3rd pressure chamber 83 and the 4th pressure chamber 84 are formed in the unit case 76, The small side of the surface which faces to the opposite side to the press rod 61 of the large diameter part of the 2nd press pin 72 is small. The part exposed from the neck part is located in the third pressure chamber 83, and the surface facing the side opposite to the pressure rod 61 of the small diameter part of the second pressure pin 72 is located in the fourth pressure chamber 84. In the example shown in the figure, the area of the part exposed from the small diameter part and the area of the surface facing the opposite side to the pressure rod 61 of the small diameter part are equal among the surfaces facing the pressure rod 61 of the large diameter part. .

Two signal pressures Pa and Pb by the hydraulic oil discharged from the hydraulic pump 10 are input into the pressure chambers 83 and 84, respectively. That is, the signal pressure Pa is input to the third pressure chamber 83, and acts on the portion exposed from the small diameter portion among the surfaces facing the pressure rod 61 on the large diameter portion to press the second pressure pin 72 to the pressure rod. It is pressed toward 61. In addition, the signal pressure Pb is input to the fourth pressure chamber 84 to act on the surface facing the pressure rod 61 opposite to the small diameter portion to press the second pressure pin 72 toward the pressure rod 61. At this time, the pressing force for pressing the second pressing pin 72 toward the pressing rod 61 is the sum of the pressing force by the signal pressure Pa and the pressing force by the signal pressure Pb.

In the hydraulic pump 10 of the split flow structure, when the pressure rod 61 is to be pressurized by the pressure pins with two signal pressures Pa and Pb by the hydraulic oil discharged from the hydraulic pump 10, two pressure pins are applied. It becomes necessary. On the other hand, according to the sum of the two signal pressures Pa and Pb by the hydraulic oil discharged from the hydraulic pump 10, the pressurizing rod 61 is pressurized toward the inclination plate 40 using one 2nd pressurizing pin 72. FIG. can do. Therefore, the number of parts of the pressurizing pin unit 70 can be reduced.

Moreover, the 2nd press pin 72 of this modification has the function of the adjustment pin 73 in the hydraulic pump 10 shown in FIG. That is, the 2nd press pin 72 is able to adjust the position in the longitudinal direction by the adjuster 77. As shown in FIG. In this case, one second pressing pin 72 functions as three pins of two pressing pins and one adjusting pin, so that the number of parts of the pressing pin unit 70 can be further reduced.

12 is a cross-sectional view showing still another modification of the hydraulic pump 10. The hydraulic pump 10 of this modification is a so-called split flow structure hydraulic pump having the function of two pumps as one pump in the same manner as the modification described with reference to FIG. 11, and is discharged from the hydraulic pump 10. Two signal pressures by the hydraulic oil are output.

In the illustrated example, the pressing pin unit 70 has a second pressing pin 72, an adjuster 77, and a unit case 76. The second pressing pin 72 is formed in a cylindrical shape and has a circular cross section when viewed along the longitudinal direction of the second pressing pin 72. The 5th pressure chamber 85 is formed in the unit case 76, and the surface which faces to the opposite side to the pressure rod 61 of the 2nd pressure pin 72 is located in the 5th pressure chamber 85. As shown in FIG.

The intermediate pressure Pc of two signal pressures by the hydraulic oil discharged from the hydraulic pump 10 is input into the 5th pressure chamber 85. Intermediate pressure Pc is a signal pressure which has a pressure which becomes the middle of two signal pressures, and when two signal pressures are called Pa and Pb,

Pc = (Pa + Pb) / 2... (One)

It becomes As this intermediate pressure Pc, the "intermediate pressure P 'which generate | occur | produced in the" pressure communication path 54 "by the pressure oil which flowed out from the" opening hole 53 "in Unexamined-Japanese-Patent No. 6-307330, for example. Can be used.

According to this modification, the effect equivalent to the modification demonstrated with reference to FIG. 11 can be exhibited. According to the present modification, the second press pin 72 can be made into a simple cylindrical shape, and a pressure chamber provided in the unit case 76 corresponding to the second press pin 72 is provided as one fifth. The pressure chamber 85 can be used. Therefore, the structure of the pressurizing pin unit 70 can be simplified.

In the modified example described with reference to FIGS. 11 and 12, one or more first pressing pins 71 may be provided in addition to the second pressing pins 72.

As another modification, the embodiment described with reference to FIGS. 1 and 2 has shown that the hydraulic pump 10 has four first press pins 71, but the present invention is not limited thereto. The hydraulic pump 10 may have two, three, or five or more first press pins 71.

In addition, although some modifications to the above-described embodiment have been described above, it is naturally possible to apply a plurality of modifications in appropriate combination.

10: hydraulic pump
14: gear pump
16: axis of rotation
20: housing
21: first housing block
23: first guide portion
29: recess
22: second housing block
25: axis of rotation
30: cylinder block
32: cylinder hole
35: suction plate
38: piston
39: cylinder chamber
40: inclined plate
41: sliding surface
42: contact surface
43: shoe
50: first pressing means
51: first retainer
52: second retainer
54: first spring
55: second spring
60: second pressurizing means
61: pressurized rod
61a: cross section
61b: back section (section)
61c: side
65: oil retaining groove
68: supply hole
70: pressure pin unit
71: first pressing pin
72: second pressing pin
73: adjustment pin
75: second guide part
76: unit case
77: adjuster
78: convex
81: first pressure chamber
82: second pressure chamber
83: third pressure chamber
84: fourth pressure chamber
85: fifth pressure chamber
91: orifice
93: slow return mechanism
94: orifice
95: check valve
97: electromagnetic proportional valve
99: shuttle valve
A: axis of rotation
L: supply line
P: signal pressure
S: oil source

Claims (10)

A cylinder block rotating around a rotation axis, the cylinder block having a plurality of cylinder holes formed therein;
A piston that is slidably held in each cylinder hole,
An inclined plate for sliding each piston in each cylinder hole by rotating the cylinder block around the rotation axis, the inclined plate configured to be able to change its tilting angle;
First pressing means for pressing the inclined plate in a direction in which the tilting angle of the inclined plate increases;
And a second pressing means for pressing the inclined plate in a direction in which the tilting angle of the inclined plate becomes small,
The second pressing means has a pressing rod for pressing the inclined plate,
At least one of a flow control signal pressure and a horsepower shift signal pressure acts on the cross section opposite to the inclined plate in the pressure rod. The method of claim 1,
The hydraulic pump in which the said flow control signal pressure acts on the said cross section. The method of claim 2,
And the flow control signal pressure is a negative flow control signal pressure. The method according to any one of claims 1 to 3,
The flow control signal pressure or the horsepower shift signal pressure acting on the cross section through an orifice. The method according to any one of claims 1 to 3,
Wherein the flow control signal pressure or the horsepower shift signal pressure acts on the cross section via a slow return mechanism. The method according to any one of claims 1 to 5,
The said flow control signal pressure or the said horsepower shift signal pressure is a hydraulic pressure pump signal which the electric signal was hydraulically converted by the electromagnetic proportional valve. The method according to any one of claims 1 to 6,
And a signal pressure having a relatively high pressure among the flow control signal pressure and the horsepower shift signal pressure acts on the cross section. The method according to any one of claims 1 to 7,
It further has a guide for guiding the side of the pressing rod,
Hydraulic pressure is supplied from the other pump between the side and the guide portion. The method of claim 8,
The guide portion is provided with a supply hole for supplying pressure oil from the other pump between the side surface and the guide portion,
The side surface is provided with an oil holding groove for holding the pressurized oil supplied from the supply hole,
The oil holding groove is a hydraulic pump that faces the supply hole at any position during the advancing / reducing operation along the guide portion of the pressure rod. The method according to any one of claims 1 to 9,
The second pressing means further has a pressing pin,
The pressure pin is a hydraulic pump that presses the inclined plate through the pressure rod in accordance with a signal pressure corresponding to the pressure pin.

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