JPH0553944B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial Application Field The present invention relates to a piston-type pump or motor that can be used in various hydraulic equipment fields.

(B) Prior art Pumps or motors (meaning fluid machines that function as pumps when rotary power is applied and function as motors when high-pressure hydraulic oil is input) mainly used in the field of hydraulic equipment can be roughly divided into gears. These days, piston-type pumps or motors are preferred to be used instead of gear-type pumps or motors or vane-type pumps or motors. This is because piston-type pumps or motors have the advantage of being highly efficient, allowing the size to be changed steplessly, and being suitable for high-pressure applications. Piston pumps or motors with high oblique axis are attracting attention.

By the way, a variable displacement oblique axis type piston pump or motor has a cylinder block that holds a piston and a port block that distributes and supplies hydraulic oil to each cylinder hole of this cylinder block, which are tilted with respect to the rotation axis. It is possible. By tilting this port block using a hydraulic actuator or the like, the angle between the axial center of the cylinder block and the rotation center of the rotating shaft is changed, and thereby the piston is rotated per rotation. The displacement volume can be adjusted. In the conventional type, the actuator is actuated by pilot pressure, and the pilot pressure is selectively supplied by a directional control valve disposed outside the casing to move the cylinder block in the capacity increasing direction or I am trying to move it in the direction of decreasing capacity.
However, simply by stopping the pilot pressure supply or switching the supply direction using an externally placed directional control valve, it is not possible to accurately determine the operating position of the cylinder block, so it is necessary to perform highly accurate variable displacement control. is difficult.

Note that in order to perform precise variable displacement control, it is possible to detect the operating position of the cylinder block, feed back this detection signal to a servo valve, and control the actuator with this servo valve. Control systems have complex structures. Therefore, it is not practical except in cases where extremely precise control is required.

(c) Purpose The present invention was made in view of the above circumstances, and provides a variable displacement piston pump or motor that has a simple structure and can accurately adjust the inclination angles of the cylinder block and port block. The purpose is to provide

(D) Structure In order to achieve the above object, the present invention includes a pair of hydraulic actuators with different diameters, which are provided in positions where the tilt angle adjustment mechanism can tilt the port block in opposite directions, and a pair of hydraulic actuators with different diameters, and a pair of hydraulic actuators with different diameters. It is provided in the port block so as to be substantially aligned with the moving direction of the port block, and its switching movement causes the drive pressure fluid to be supplied to both the actuators at the same time, or the drive pressure fluid is supplied only to the smaller diameter actuator. A valve body that selectively releases the actuator with a larger diameter to the case drain, and an operating member for switching and moving this valve body, and an external force is applied to the operating member. The present invention is characterized in that the port block is configured to be able to follow the movement caused by the movement.

(e) Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic vertical sectional view of a piston pump or motor according to the present invention, and numeral 1 in the figure is a casing. The casing 1 consists of a cylindrical front cover part 2 and a rear cover part 3 which is liquid-tightly attached to the rear end opening of the front cover part 2.The rear cover part 3 has a pair of outflow ports. Inlet ports 4 and 5 are open. A rotating shaft 6 is housed within this casing 1. The rotating shaft 6 is for input or output, and is supported by the casing 1 via a first bearing 7.
Its outer end 6a extends outside through an opening 2a provided in the front cover section 2. Further, a spline grooved portion 6b is provided at a portion of the rotating shaft 6 located inside the casing 1, and a torque plate 8 is fitted into this spline grooved portion 6b. The torque plate 8 is disc-shaped and rotates together with the rotating shaft 6. A cylinder block 9 is disposed behind the torque plate 8, and a port block 11 is disposed behind the cylinder block 9. The cylinder block 9 is tiltable with respect to the rotation center M of the torque plate 8 and the rotary shaft 6, and has a movable axis L (FIG. 1 shows a neutral position, in this case, the movable axis L). It is a thick-walled cylindrical body rotatably provided around the center of rotation (L coincides with the rotation center M), and specifically, the rear end surface 9a is connected to the port block 11.
It is rotatably fitted to the outer periphery of an inclined cylinder 13 implanted in the port block 11 while being in sliding contact with the front end surface 12 of the port block 11. Further, the cylinder block 9 is provided with a plurality of cylinder holes 14 that are parallel to the movable axis L and open toward the torque plate 8 at equal angular intervals in the circumferential direction. A piston 15 is slidably fitted into each of these cylinder holes 14. piston 15
When fitted into the cylinder hole 14, the piston main body 16 and the rod portion 17 extending outward from the piston main body 16 are integrally formed. It includes a fitting part 18 that fits into the inner periphery of the hole 14 with an appropriate interval (approximately 0.05 mm), and a piston ring 21 interposed between the fitting part 18 and the holding plate 19. . The tip of the rod portion 17, that is, the outer end 15a of the piston 15 is formed into a spherical shape, and the outer end 15a is pivotally supported on the torque plate 8. Specifically, the same number of spherical seats 22 as the pistons 15 are provided on one end surface of the torque plate 8 at equal angular intervals in the circumferential direction, and each of the pistons 15 is provided on each of these spherical seats 22.
The outer ends 15a of the two are rotatably fitted together. A piston retainer 23 prevents each piston 15 from coming off the torque plate 8. Further, the port block 11 is a thick-walled cylindrical body that is provided so as to be tiltable with respect to the rotation center M of the torque plate 8 and the rotation shaft 6. Specifically, the port block 11 has a front end surface 12 that is tiltable with respect to the rotation center M of the torque plate 8 and the rotation shaft 6. 9, the curved rear end surface 20 is brought into sliding contact with a sliding surface 24 formed on the rear cover part 3, and the cylinder block 9 is tilted integrally with the cylinder block 9 via the inclined cylinder 13. It is possible. However, this sliding surface 24
is formed into an arc shape when viewed from the side, and its center of curvature Q is the intersection of the rotation center M and the tilt axis L. Further, a synchronizing mechanism 25 is provided between the torque plate 8 and the cylinder block 9, and as the torque plate 8 and the cylinder block 9 rotate synchronously, each piston 1
The volume of the pump chamber 26 formed on the inner end 15b side of the pump 5 is increased or decreased. The synchronizing mechanism 25 includes a ring member 29 having an annular attachment portion 27 at its base end and inward teeth 28 at its tip.The annular attachment portion 27 is fitted onto the inner periphery of the cylinder block 9. At the same time, the inward teeth 28 are engaged with the rear end portions of the spline grooves 6b. Specifically, the ring member 29
is a stepped cylindrical body made of a thin steel plate or the like, and the annular attachment portion 27 forming the large diameter portion is fixed to the inner periphery of the cylinder block 9 using a pin 31. Then, a number of inward teeth 28 corresponding to the number of spline grooves 6b are provided at equal pitches at the open end of the small diameter portion, and these inward teeth 28 are tiltably engaged with the spline grooves 6b. Further, the pump chamber 26 is connected to the piston 15.
This chamber is formed by the piston body 16 and the cylinder hole 14, and is opened to the rear end surface 9a of the cylinder block 9 via the fluid passage 32. As shown in FIG. 4, connection ports 33 and 34 are opened in the front end surface 12 of the port block 11 that slides on the rear end surface 9a of the cylinder block 9, and the connection ports 33 and 34 are opened in the rear end surface 20 of the port block 11. The connection ports 35 and 36 communicating with the inflow and outflow ports 4 and 5 are opened, and the connection port 33 and the connection port 35 are connected through the communication hole 37, and the connection port 34 and the connection port 36 are connected through the communication hole 38. They communicate with each other through the In this way, the connection port 33 that communicates with one of the inflow and outflow ports 4 is connected to the torque plate 8.
A connection port that communicates with the pump chamber 26 located in a region on the right side of FIG. 34 is a pump chamber 26 existing in a region to the left of the virtual dividing plane N.
They are each formed in a semicircular arc shape so as to communicate with each other.

And this piston pump or motor is
The fitting length t of the piston 15 into the cylinder hole 14 is set to a small value of about 1 mm, and the maximum value of the inclination angle θ of the movable axis L with respect to the rotation center M is 15 degrees or less, preferably 10 degrees. It is set so that it is about . Further, the inner end 6b side of the rotating shaft 6 is connected to the torque plate 8, the cylinder block 9, and the port block 11.
extends to the rear cover portion 3 of the casing 1, and its extending end is supported by a second bearing 39 provided on the rear cover portion 3.

Further, an end surface 41 of the torque plate 8 on the side opposite to the cylinder block is supported by a pressure receiving surface 43 provided on the casing 1 via a hydrostatic bearing 42. Specifically, a pressure pocket 44 is formed in each spherical seat 22 of the torque plate 8, a pressure fluid introduction path 45 is provided in the axial center of the piston 15, and the pump chamber is inserted into the pressure pocket 44. A portion of the working fluid in 26 is introduced. Further, a portion of the other end surface of the torque plate 8 corresponding to each of the spherical seats 22 is made to protrude in a circular shape, and the protruding surface 41 thereof is brought into close contact with a pressure receiving surface 43 provided on the front cover portion 2. Also,
The hydrostatic bearing 42 is constructed by providing a pressure pocket 46 on the protruding surface 41 and introducing a part of the pressure fluid in the pump chamber 26 into the pressure pocket 46 through a pressure fluid introduction path 47. The resultant force of the axial pressure of the pressure liquid in the pressure pocket 46 and the resultant force of the axial pressure of the pressure liquid in the pressure pocket 44 are made to be substantially balanced.

Furthermore, in such a device, a coil spring 48 is wound around the outer periphery of the ring member 29 of the synchronization mechanism 25, and the biasing force of the coil spring 48 moves the torque plate 8 and the cylinder block 9 to receive the corresponding pressure. It is designed to be in rolling contact with the surface 43 and the front end surface 12 at all times.
That is, this coil spring 48 is of a compression type, and has one end in contact with the stepped end face of the ring member 29 and the other end in contact with the end face of the torque plate 8.

In such a device, an inclination angle adjustment mechanism 51 is further provided in association with the port block 11. The inclination angle adjustment mechanism 51 includes a first hydraulic actuator 52 provided at one end in the rotational direction of the port block 11, a second hydraulic actuator 53 provided at the other end in the rotational direction, and the connection port. A hydraulic fluid supply line 54 leads the higher pressure of the hydraulic fluids present in the hydraulic actuators 33 and 34 to the first hydraulic actuator 52, and a hydraulic fluid supply line 54 leads the second hydraulic actuator 53 to the hydraulic actuator 52.
4 or a switching valve 56 selectively connected to the case drain 55. The first hydraulic actuator 52 has a cylinder 57 that opens upwardly formed at the upper end of the port block 11, a piston 58 that is slidably fitted into the cylinder 57, and a rod 59 that is pivotally connected to the piston 58. The top surface 59a of the top wall inner surface 1a of the casing 1
It is in contact with the And these both sides 1a, 5
A pressure pocket 61 is formed between the cylinders 9a and 9a, and a portion of the hydraulic fluid in the cylinder 57 is introduced into the pressure pocket 61 through a port 62, thereby forming a hydrostatic bearing. Also,
The second hydraulic actuator 53 has a cylinder 63 that opens downward at the lower end of the port block 11, and a piston 64 that is connected to the cylinder 63.
The rod 65 is slidably fitted into the piston 64, and the distal end surface 65a of the rod 65 pivotally connected to the piston 64 is brought into contact with the inner surface 1b of the bottom wall of the casing 1. and,
A pressure pocket 66 is formed between these both surfaces 1b and 65a, and a portion of the hydraulic fluid in the cylinder 63 is introduced into this pressure pocket 66 through a port 67, thereby forming a hydrostatic bearing. ing. On the other hand, the hydraulic fluid supply line 54 has first and second ports communicating with the connection ports 33 and 34, respectively.
Second fluid passages 68 and 69 and a common fluid passage 72 which has one end communicating with these fluid passages 68 and 69 via a high pressure selection valve 71 and the other end connected to the cylinder 57 of the first hydraulic actuator 52. It is equipped with the following. The high pressure selection valve 71 has a valve body 71a that is operated by a pressure difference between the fluid passages 68 and 69. That is, the valve body 71a is configured to close the fluid passages 69, 68 on the low pressure side and connect the fluid passages 68, 69 on the high pressure side to the common fluid passage 72. Also,
As shown in FIG. 3, the switching valve 56 has a spool holding hole 73 formed in the port block 11 that communicates with the case drain 55, and a spool 74 serving as a valve body can be slid into the spool holding hole 73. It is mated to The spool holding hole 73 is provided with its axis substantially aligned with the moving direction of the port block 11, and therefore,
The spool 38 is slidable in the same direction of movement. Spool 74 is land 7
A fluid circulation groove 77 is provided between 5 and 76. Then, an inflow port 78 communicating with the cylinder 57 of the first hydraulic actuator 52 is opened at a portion of the inner periphery of the spool holding hole 73 corresponding to the fluid circulation groove 77, and a portion corresponding to the land 75 is opened. One end 79a of the inflow/outflow port 79 communicating with the cylinder 63 of the second hydraulic actuator 53 is opened. Also,
An operating rod 81 is protruded from one end of the spool 74, and extends to the outside of the casing 1 through a through hole 82.

Next, the operation of this embodiment will be explained.

When used as a motor, for example, one of the inflow and outflow ports 4 is connected to a high pressure hydraulic pressure source (not shown), and the other inflow and outflow port 5 is connected to a tank (not shown). In the neutral position shown by the solid line in FIG.
Since the angle θ between the movable axis L, which is the axis of the rotary shaft 6, and the rotation center M of the rotating shaft 6 is zero, the torque plate 8
No torque is generated, and the rotating shaft 6 is stopped. At this time, the spool 74 of the switching valve 56
The inflow/outflow port 7 is held in the neutral position shown and communicates with the cylinder 57 of the first hydraulic actuator 52 and the cylinder 63 of the second hydraulic actuator 53.
9 are both in a blocked state.
Therefore, the hydraulic fluid in the high pressure side connection port 33 passes through the hydraulic fluid supply line 54 to the cylinder 5.
7, the port block 11 maintains its stopped position.

From this state, when the operating rod 81 is pulled upward in the figure by a required amount, the spool 74 of the switching valve 56 slides, and the spool 74 of the switching valve 56 slides.
The land 75 of No. 4 is connected to the open end 79 of the inflow/outflow port 79.
It will be displaced upwards from point a. the result,
The inflow port 78 and the outflow/inflow port 79 communicate with each other, and the lock state of the hydraulic actuator 53 is released, and high-pressure hydraulic fluid is also introduced into the cylinder 63 of the actuator 53.
In other words, the pressure of the hydraulic fluid in the high-pressure side connection port 33 acts on the cylinders 57 and 63 of both the actuators 52 and 53. Therefore, the actuation force of the second hydraulic actuator 53, which has a large piston and cylinder diameter, exceeds the actuation force of the first hydraulic actuator 52, and the port block 11 moves upward on the curved surface 24 in the figure.
It is moved while tilting along the Along with this, the cylinder block 9 also moves upward and tilts, and the inclination angle θ of the movable axis L with respect to the rotation center M gradually increases. Therefore, the piston 15 held by the cylinder block 9 and the torque plate 8 work together to function as a well-known oblique shaft motor, and the rotary shaft 6 rotates. Then, when the port block 11 moves upward by an amount corresponding to the amount of movement of the operating rod 81, the port block 11 moves toward the spool 7.
4, and the inflow and outflow ports 79
is again closed by the land 75 of the spool 74, and the second hydraulic actuator 53 is locked, and the tilting of the port block 11 and cylinder block 9 is stopped. From this state, when the operation rod 81 is moved downward by the required amount, the land 75 of the spool 74 is moved to the open end 79 of the inflow/outflow port 79.
It deviates downward from a. As a result, the cylinder 63 of the second hydraulic actuator 53 is released into the case drain 55 through the inflow/outflow port 79, and the second hydraulic actuator 5
3 is free. Therefore, the port block 9 is moved downward in the figure by the actuation force of the first fluid actuator 52, and the inclination angle θ is
is decreasing. Then, the port block 1
1 moves downward by an amount corresponding to the amount of movement of the operating rod 81, the port block 11 catches up with the spool 74, the inflow/outflow port 79 is again blocked by the land 75, and the port block 11 Then, the cylinder block 9 stops tilting.

In this way, the inclination angle θ of the movable axis L with respect to the rotation center M is changed to a desired value including zero,
Although the capacity can be variably controlled,
This allows the port block 11 and cylinder block 9 to follow the operating rod 81 connected to the spool 74 as described above. Therefore, it is possible to make a one-to-one correspondence between the amount of operation applied to the operating rod 81 and the amount of change in capacity, and excellent operability similar to that achieved when controlling capacity using a servo system can be obtained. .
Therefore, if the operating rod 81 is operated using a worm gear mechanism, it is possible to perform variable capacity control with extremely high precision. Furthermore, this device does not require any servo valves or position detectors, so it has a simple structure and is easy to implement.

In the above embodiment, a case was explained in which the internal pressure fluid was used to operate the hydraulic actuator for driving the port block.
The present invention is not necessarily limited to this, and for example, a dedicated hydraulic fluid may be supplied separately from the outside. However, if the above embodiment is adopted, the piping can be prevented from becoming complicated and the configuration can be simplified.

Further, the hydraulic actuator is not limited to the above-mentioned type; for example, a type that operates a port block using a pair of pistons and cylinders may be used. It can be made extremely simple.

Furthermore, in the above embodiments, the case where the motor is used as a motor has been described, but it goes without saying that it can also be used as a pump.

(F) Effects The present invention has the above-mentioned configuration, so it is possible to provide a variable displacement piston pump or motor that has a simple structure and can accurately adjust the inclination angles of the cylinder block and port block. . In particular, since the inclination angle adjustment mechanism is configured with a pair of hydraulic actuators having different diameters, there is an accompanying effect that it can be easily controlled.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which FIG. 1 is a longitudinal sectional view, FIG. 2 is a sectional view taken along the line - in FIG. 1,
3 is a cross-sectional view taken along the line -- in FIG. 1, and FIG. 4 is a cross-sectional view taken along the line -- in FIG. 1... Casing, 6... Rotating shaft, 8... Torque plate, 9... Cylinder block, 9a... Rear end surface, 1
1...Port block, 14...Cylinder hole, 15...
Piston, 51...Inclination angle adjustment mechanism, 52, 53
... Hydraulic actuator, 74 ... Valve body (spool), 81 ... Operation member (operation rod).

Claims (1)

[Claims] 1. A casing with an inlet/outlet port, an input/output rotating shaft supported by this casing, a torque plate that can rotate integrally with this rotating shaft, and a movable shaft that intersects with the rotation center of this torque plate. A cylinder block that is rotatably provided and has a plurality of cylinder holes opened toward the torque plate parallel to the movable axis; and a cylinder block that is slidably fitted into each cylinder hole of the cylinder block and connected to the torque plate. and a plurality of pistons, which are provided so as to be able to tilt with respect to the center of rotation together with the cylinder block while slidingly supporting the end surface of the cylinder block on the anti-torque plate side, and connecting the inflow and outflow ports of the casing and the cylinder hole. A piston pump or a motor comprising a port block that communicates with each other, and an inclination angle adjustment mechanism that tilts the cylinder block and port block to change the inclination angle of the movable shaft center with respect to the rotation center. The mechanism includes a pair of hydraulic actuators of different diameters provided at positions where the port block can be tilted in opposite directions, and a mechanism provided within the port block with a switching direction substantially aligned with the moving direction of the port block. The switching movement selectively selects a state in which drive pressure fluid is supplied to both actuators at the same time, or a state in which drive pressure fluid is supplied only to the smaller diameter actuator and the larger diameter actuator is released to the case drain. The port block is characterized by comprising a valve body for realizing the valve body and an operation member for switching and moving the valve body, and configured so that the port block can follow a movement applied to the operation member from the outside. variable displacement piston pump or motor.