JPH0528389Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] In the present invention, a rotating body is rotationally driven by a drive source with a variable rotation speed, and the inclination angle of the swash plate is changed according to fluctuations in the rotation speed of the rotating body. This invention relates to a swash plate type variable displacement piston pump.

[Conventional technology]

Conventionally, this type of swash plate type variable displacement piston pump, as shown in Japanese Utility Model Publication No. 54-9201, has a throttle valve disposed in the liquid discharge flow path, and the pressure on the front side and the pressure on the rear side of the throttle valve are controlled. A control connected to the swash plate that acts oppositely on the spool of the pressure compensation valve and changes the inclination angle of the swash plate by moving the spool to a position where the acting force based on the pressure difference between the front and rear of the throttle valve and the elastic force of the spring are balanced. One end of the piston is switched to communicate with the front side of the throttle valve and the low pressure side. Now, when a rotating body composed of a drive shaft and a cylinder block is rotationally driven by a drive source with a variable rotation speed, discharged liquid is supplied to a load through a throttle valve. As the rotational speed increases, the acting force based on the pressure difference between the front and rear of the throttle valve becomes larger than the elastic force of the spring, and the spool of the pressure compensation valve moves to a position where the acting force and the elastic force are in equilibrium, throttling one end of the control piston. In switching communication with the front side of the valve, the control piston moves to reduce the angle of inclination of the swash plate, thereby reducing the discharge amount. Conversely, when the rotation speed decreases and the acting force based on the pressure difference between the front and rear of the throttle valve becomes smaller than the elastic force of the spring, the spool of the pressure compensation valve moves to a position where the acting force and the elastic force are in equilibrium, and one end of the control piston is switched to the low pressure side, the control piston moves to increase the inclination angle of the swash plate, and the discharge amount increases. In this way, the inclination angle of the swash plate is changed in response to variations in the rotational speed.

[Problem that the invention attempts to solve]

However, such conventional pumps require a throttle valve disposed in the discharge flow path and a pressure compensation valve in which the front pressure and rear pressure of the throttle valve act oppositely on the spool. Since the pump must be connected to the valve via piping, there are many piping connections, which can easily cause liquid leakage from the connections due to pump operating vibrations, making maintenance and management of the pump complicated. .

The present invention solves this problem by changing the inclination angle of the swash plate according to fluctuations in rotational speed by using the centrifugal force generated by the rotational drive of the rotating body without using various valves. The present invention provides a swash plate type variable displacement piston pump that can simplify maintenance management.

[Means for solving problems]

For this reason, the present invention includes a rotating body that is rotatably supported inside the pump body and is rotationally driven by a drive source with a variable rotation speed, and a rotating body that reciprocates to draw in and discharge liquid by the rotational drive of the rotating body. A plurality of pistons are slidably installed, and the pistons are tiltably supported inside the pump body, and by increasing the inclination angle, the amount of reciprocating sliding of the pistons provided on the rotating body is increased, and the amount of liquid discharged is increased, and the inclination angle is increased. A swash plate connected to the piston to reduce the reciprocating sliding amount of the piston and reduce the amount of liquid discharged, an elastic member that applies elastic force to the swash plate in the direction of increasing the inclination angle, and an elastic member. A conversion mechanism is provided inside the pump body so as to act in opposition to the elastic force and press the swash plate in the direction of decreasing the inclination angle. A plurality of blade members are formed and provided inside the conical hole, and a plurality of blade members are provided on the outer periphery of the rotating body so as to be movable in the axial direction and radial direction and rotate together with the rotating body, with the outer circumferential surface in contact with the inner circumferential surface of the conical hole.
The outer circumferential surface of each blade member that comes into contact with the inner circumferential surface of the conical hole is
Each blade member is pressed against the inner peripheral surface of the conical hole by the centrifugal force generated by the rotational drive of the rotating body, and the horizontal component of the reaction force moves in the axial direction to press the swash plate in the direction of decreasing the inclination angle. It is formed into a tapered arcuate surface that gradually expands toward the swash plate side.

[Effect]

In the configuration of the present invention, as the rotational speed increases, the centrifugal force generated by the rotational drive of the rotating body increases, and the increase in centrifugal force causes the conversion mechanism to become elastic due to the increased pressing force of each blade member against the swash plate. The inclination angle of the swash plate decreases against the elastic force of the member. In addition, as the rotational speed decreases, the centrifugal force generated by the rotational drive of the rotating body decreases, and due to the decrease in centrifugal force, the pressing force of each blade member against the swash plate decreases, and the conversion mechanism is activated by the elastic force of the elastic member. The tilt angle of the swash plate increases. Therefore, the inclination angle of the swash plate is mechanically changed in response to fluctuations in rotational speed by using the centrifugal force generated by the rotation of the rotating body, making it possible to connect various valves such as those in conventional pumps. There are no piping connections, which simplifies maintenance and management of the pump.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings.

In FIGS. 1 and 2, reference numeral 1 denotes a pump body, which is constructed by fixing a lid member 3 to a hollow housing body 2 with an opening on one side so as to close the opening. Reference numeral 4 denotes a drive shaft rotatably supported inside the pump body 1, with one end protruding from the pump body 1 and connected to a variable speed drive source (not shown). Reference numeral 5 denotes a cylinder block, which is supported by the drive shaft 4 through a spline portion 6 formed in the middle of the drive shaft 4 and rotated together with the drive shaft 4, and together with the drive shaft 4 constitutes a rotating body 7. . Numeral 8 denotes pistons provided on the cylinder block 5 so as to be able to slide back and forth, and nine pistons are arranged at equal intervals in the circumferential direction of the cylinder block 5. Reference numeral 9 denotes a swash plate supported inside the pump body 1 so as to be tiltable within a certain range of inclination angle, and is connected to the piston 8 via a shoe 10. Reference numeral 11 denotes a spring as an elastic member, which is interposed between the back surface of the swash plate 9 on the side that contacts the shoe 10 and the inner surface of the housing body 2, and applies elastic force to the swash plate 9 in the direction of increasing the inclination angle. It is set up as follows. Then, due to the elastic force of the spring 11, the swash plate 9
When the rotating body 7 is driven to rotate with the inclination angle of the piston 8 at its maximum, the amount of reciprocating sliding of the piston 8 becomes maximum and the maximum discharge amount can be obtained. Further, by reducing the inclination angle of the swash plate 9 by a pressing force, which will be described in detail later, which acts on the swash plate 9 in opposition to the elastic force of the spring 11, the amount of reciprocating sliding of the piston 8 is reduced, and the discharge amount is reduced. 12 is a liquid suction channel, and 13 is a liquid discharge channel. 1
Reference numeral 4 denotes a conversion mechanism that converts the centrifugal force generated by the rotational drive of the rotating body 7 into a pressing force on the swash plate 9 so as to change the inclination angle of the swash plate 9 according to the fluctuation in the rotational speed of the rotating body 7, and the pump body 1, and protrudes from the outer periphery of the cylinder block 5 to form six protrusions 15 at equal intervals in the circumferential direction, and each protrusion 15 has a blade member 1 attached thereto.
6 is fitted so as to be movable in the axial direction and the radial direction. The housing body 2 is disposed on the outer periphery of the blade member 16.
A conical member 18 having a conical hole 17 that is fixedly installed inside the swash plate 9 and whose diameter gradually increases toward the swash plate 9 side is arranged, and each blade member 16 is attached to the swash plate so that the outer peripheral surface corresponds to the inner peripheral surface of the conical hole 17. It is formed into a tapered arcuate surface that gradually expands toward the 9 side, and is provided in contact with the inner circumferential surface of the conical hole 17. A disk-shaped pressing piston 19 is in contact with one side of each blade member 16 on the swash plate 9 side. The swash plate 9 is in contact with the back surface of the side that is in contact with the swash plate 9. Each blade member 16 rotates together with the cylinder block 5 and is pressed against the inner peripheral surface of the conical hole 17 of the conical member 18 by the centrifugal force generated by the rotational drive of the cylinder block 5, and the reaction force of the pressed force is applied to each blade. The horizontal component of this reaction force acts on the member 16 and becomes a pressing force that moves each blade member 16 leftward in FIG. 1 along the inner circumferential surface of the conical hole 17. The swash plate 9 is provided so as to be pressed in the direction of decreasing the inclination angle through the swash plate 9. Next, the operation of this configuration will be explained.

In the first illustrated state, the tilt angle of the swash plate 9 is increased by the elastic force of the spring 11. In this state, when the drive shaft 4 is rotationally driven by a variable speed drive source, the cylinder block 5 is driven. The piston 8 is driven to rotate together with the shaft 4, and the piston 8 is rotated with the cylinder block 5.
Discharges liquid by sliding back and forth with the rotational drive of the
Since the angle of inclination of the swash plate 9 is maximum, the amount of reciprocating sliding of the piston 8 is maximum, and the maximum discharge amount per rotation can be obtained. At this time, each blade member 16 of the conversion mechanism 14 presses the swash plate 9 due to the centrifugal force generated by the rotational drive of the cylinder block 5, but the pressing force by each blade member 16 is smaller than the elastic force of the spring 11, and the swash plate 9 maintains the state shown in the first diagram. Therefore, as shown in FIG. 3, the discharge amount increases as the rotational speed increases. Then, when the rotational speed increases to the NI point in FIG. , the swash plate 9 tilts to the left from the state shown in the first figure until the swash plate 9 reaches an equilibrium position between the opposing pressing force and the elastic force, reducing the inclination angle and reducing the discharge amount. Thereafter, as the rotational speed increases, the centrifugal force increases and the pressing force that presses the swash plate 9 increases, and the swash plate 9 sequentially tilts to the left, gradually decreasing the inclination angle, and the discharge amount gradually decreases. Decrease. From this state, when the rotation speed is decreased, the centrifugal force decreases as the rotation speed decreases, and the pressing force that presses the swash plate 9 decreases at the rotation speed up to the NI point in FIG. Habane 11
Due to the elastic force of , the inclination angle is sequentially increased by sequentially tilting to the right, and the discharge amount is sequentially increased. When the rotation speed decreases to the NI point in Fig. 3, the inclination angle of the swash plate 9 returns to the maximum inclination angle as shown in Fig. 1, and the discharge amount reaches the maximum. The amount decreases and the amount of discharge becomes zero due to stopping.

With this operation, the centrifugal force generated by the rotational drive of the cylinder block 5 constituting the rotating body 7 is converted into a pressing force that presses the swash plate 9 by each blade member 16 of the conversion mechanism 14, and the inclination angle of the swash plate 9 is changed. Since the rotational speed of the cylinder block 5 is changed according to variations in the rotational speed, there is no need for piping connections between various valves as in conventional pumps, and maintenance and management of the pump can be simplified.

Further, each blade member 16 of the conversion mechanism 14 moves in the axial direction along the inner peripheral surface of the conical hole 17 due to the centrifugal force generated by the rotational drive of the cylinder block 5, and the swash plate 9
This is because the pressing force applied to the swash plate is obtained mechanically by the rotational drive of the cylinder block 5, compared to conventional pumps in which the pressing force acting on the swash plate is obtained from the pressure of the discharged liquid. As the centrifugal force changes as the rotation speed of the cylinder block 5 changes, the pressing force for pressing the swash plate 9 can be accurately varied, and the inclination angle of the swash plate 9 can be adjusted accurately according to the change in the rotation speed of the cylinder block 5. can be changed to .

FIG. 4 shows another embodiment of the present invention.
To explain only the parts that differ from one embodiment,
The conversion mechanism 20 has a plurality of protrusions 25 protruding from the outer periphery of a drive shaft 23 that constitutes a rotating body 22 together with a cylinder block 21, and a blade member 26 is attached to each protrusion 25 in the axial and radial directions. It is movably fitted into the The housing body 2 is disposed on the outer periphery of the blade member 26.
7, a conical member 29 having a conical hole 28 whose diameter gradually increases toward the swash plate 24 side is arranged, and the outer circumferential surface of each blade member 26 is inclined so as to correspond to the inner circumferential surface of the conical hole 28. It is formed into a tapered arcuate surface that gradually expands toward the plate 24 side, and is provided in contact with the inner circumferential surface of the conical hole 28 . A disk-shaped pressing piston 30 is in contact with one side of each blade member 26 on the swash plate 24 side.
The pressing piston 30 is provided inside the housing main body 27 so as to be non-rotatable and movable in the axial direction, and is attached to each blade member 2.
The swash plate 24 is in contact with a rod portion 31 protruding from the rear surface on the side where the swash plate 6 is in contact. And each blade member 2
6 rotates together with the drive shaft 23, and the conical member 29 is rotated by the centrifugal force generated by the rotation of the drive shaft 23.
The reaction force of this pressing force acts on each blade member 26, and the horizontal component of this reaction force causes each blade member 26 to move toward the right in FIG. This becomes a pressing force that moves along the inner peripheral surface of the piston 30, and this pressing force causes the rod portion 3 of the pressing piston 30
1 to press the swash plate 24 in the direction of decreasing the inclination angle.

In operation, each vane member 26 of the conversion mechanism 20 presses the swash plate 24 with the centrifugal force generated by the rotation of the drive shaft 23, and this pressing force increases as the rotation speed of the drive shaft 23 increases, causing the spring 11 to When the elastic force becomes greater than the elastic force, the swash plate 24 is tilted to the left from the state shown in the fourth figure until the pressing force and the elastic force are balanced, the inclination angle is decreased, and the discharge amount is decreased. From this state, when the rotation speed is reduced, the pressing force that presses the swash plate 24 decreases, and the swash plate 24 tilts to the right due to the elastic force of the spring 11 to a position where the reduced pressing force and the elastic force are balanced. Increasing the inclination angle increases the discharge amount. Then, when the number of revolutions decreases to a certain number of revolutions,
The inclination angle of the swash plate 24 returns to the maximum inclination angle in the fourth illustrated state, and the discharge amount becomes maximum.Thereafter, the discharge amount decreases as the rotational speed decreases, and the discharge amount becomes zero when the rotation speed decreases.

With such an operation, similarly to the embodiment, the rotating body 22
By using the centrifugal force generated by the rotation of the drive shaft 23 constituting the pump, it is possible to change the inclination angle of the swash plate 24 in accordance with variations in the rotational speed, thereby simplifying the maintenance and management of the pump. In addition, each blade member 26 of the conversion mechanism 20 moves in the axial direction along the inner peripheral surface of the conical hole 28 by the centrifugal force generated by the rotational drive of the drive shaft 23, creating a pressing force that presses the swash plate 24. As in the embodiment, the pressing force for pressing the swash plate 24 can be accurately varied as the rotation speed of the drive shaft 23 changes, and the inclination angle of the swash plate 24 can be accurately changed according to the change in the rotation speed of the drive shaft 23. can do.

[Effect of idea]

In this way, the present invention includes a rotating body that is rotatably supported inside the pump body and rotationally driven by a drive source with a variable rotation speed, and a rotating body that sucks and discharges liquid by the rotational drive of the rotating body. The amount of reciprocating sliding of the pistons installed on the rotating body is increased by increasing the amount of reciprocating sliding of the pistons, which are supported in the pump body so as to be freely tiltable, and are provided on the rotating body by increasing the tilt angle. a swash plate connected to the piston so as to reduce the reciprocating sliding amount of the piston and reduce the amount of liquid discharged by decreasing the amount of reciprocating movement of the piston; A conversion mechanism is provided inside the pump body so as to act oppositely to the elastic force of the member and press the swash plate in the direction of decreasing the inclination angle, and the conversion mechanism has a conical hole whose diameter gradually increases toward the swash plate. In addition to being formed inside the pump body, a plurality of blade members are provided on the outer periphery of the rotating body with their outer circumferential surfaces in contact with the inner circumferential surface of the conical hole, and are movable in the axial direction and radial direction and rotate together with the rotating body. Each blade member is pressed against the inner circumferential surface of the conical hole by the centrifugal force generated by the rotational drive of the rotating body, and the horizontal component force due to this reaction force presses the outer circumferential surface of the blade member that comes into contact with the inner circumferential surface of the conical hole. It is formed into a tapered arcuate surface that gradually expands toward the swash plate so that it moves in the axial direction and presses the swash plate in the direction of decreasing the inclination angle, and utilizes the centrifugal force generated by the rotational drive of the rotating body. Since the inclination angle of the swash plate is mechanically changed according to the change in rotation speed, maintenance and management of the pump can be simplified compared to conventional pumps that use various valves. .

In addition, the centrifugal force generated by the rotational drive of the rotating body moves each blade member of the conversion mechanism in the axial direction along the inner peripheral surface of the conical hole to obtain the pressing force that presses the swash plate, so the rotation of the rotating body Since the centrifugal force changes as the number changes, the pressing force that presses the swash plate can be accurately varied, and the inclination angle of the swash plate can be accurately changed in response to changes in the rotational speed of the rotating body. .

[Brief explanation of the drawing]

Figures 1 to 3 show an embodiment of the present invention, in which Figure 1 is a longitudinal sectional view of a swash plate type variable displacement piston pump, and Figure 2 is a sectional view taken along the line - in Figure 1. 3 is a pump characteristic diagram, and FIG. 4 is a longitudinal sectional view of a swash plate type variable displacement piston pump showing another embodiment of the present invention. 1... Pump body, 7, 22... Rotating body, 8...
... Piston, 9, 24 ... Swash plate, 11 ... Spring (elastic member), 14, 20 ... Conversion mechanism, 16, 2
6...Blade member, 17, 28... Conical hole.

Claims (1)

[Scope of utility model registration request] A rotary body rotatably supported inside the pump body and rotationally driven by a drive source with a variable rotation speed, and a plurality of rotary bodies that are slidably reciprocated on the rotary body so as to draw in and discharge liquid by the rotational drive of the rotary body. The piston is tiltably supported inside the pump body, and by increasing the inclination angle, the amount of reciprocating sliding of the piston provided on the rotating body is increased, and the amount of liquid discharged can be increased, and by decreasing the inclination angle, the amount of reciprocating sliding of the piston can be increased. a swash plate connected to the piston to reduce the amount of liquid discharged by reducing the amount of liquid discharged; an elastic member that applies an elastic force to the swash plate in the direction of increasing the inclination angle; A conversion mechanism is provided inside the pump body to press the swash plate in the direction of decreasing the inclination angle, and the conversion mechanism is provided by forming a conical hole inside the pump body whose diameter gradually increases toward the swash plate side. , a plurality of blade members are provided on the outer circumference of the rotating body, with their outer circumferential surfaces in contact with the inner circumferential surface of the conical hole, and are movable in the axial and radial directions and rotate together with the rotating body, and the inner circumferential surface of the conical hole of each blade member Each blade member is pressed against the inner circumferential surface of the conical hole by the centrifugal force generated by the rotational drive of the rotating body, and the horizontal force of the reaction force moves the swash plate in the axial direction. A swash plate type variable displacement piston pump formed with a tapered circular arc surface that gradually expands toward the swash plate side so as to press in the direction of decreasing angle.