JP2017137787A - Piston device and hydraulic mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piston device actuated by a principle different from a conventional one.SOLUTION: A piston device includes: a static cylinder; a main piston provided in the static cylinder so as to reciprocate; a moving cylinder configured to move with the main piston; a sub piston provided in the moving cylinder so as to reciprocate; and a communication state switching portion configured to switch a state of the a sub hydraulic chamber, between a communication regulating state in which the outflow/inflow of a sub hydraulic fluid from the sub hydraulic chamber formed by the moving cylinder and the sub piston is regulated, and a communication permitting state in which the outflow/inflow of the sub hydraulic fluid from the sub hydraulic chamber is permitted.SELECTED DRAWING: Figure 3

Description

  The present disclosure relates to a piston device and a hydraulic machine.

Piston devices composed of a cylinder and a piston that reciprocates within the cylinder are widely used.
For example, Patent Literature 1 describes a hydraulic pump (piston device) including a cylinder and a piston configured to be capable of reciprocating in the cylinder. In this hydraulic pump, a piston is engaged with a cam that rotates together with a rotating shaft, and the hydraulic oil in the working chamber formed by the cylinder and the piston is obtained by the piston reciprocating in the cylinder as the cam rotates. The pressure is increased.

Special table 2014-532134 gazette

In a typical piston device, similarly to the piston device described in Patent Document 1, the rotation of the rotating shaft is performed by using the reciprocating motion of a piston connected to the rotating shaft via a mechanical element including a cam and a crankshaft. Kinetic energy and fluid pressure energy are converted.
Here, if a piston device that operates on a principle different from a typical conventional piston device is obtained, application to a wider variety of products can be expected.

  In view of the above circumstances, at least one embodiment of the present invention aims to provide a piston device that operates on a principle different from the conventional one.

(1) A piston device according to at least one embodiment of the present invention includes:
A stationary cylinder;
A main piston provided in the stationary cylinder so as to be capable of reciprocating;
A movable cylinder configured to move with the main piston;
A sub-piston provided in the movable cylinder so as to be capable of reciprocating;
A communication restriction state in which the inflow and outflow of the auxiliary hydraulic oil from the auxiliary hydraulic chamber formed by the movable cylinder and the auxiliary piston is restricted, and the communication permission in which the inflow and inflow of the auxiliary hydraulic oil from the auxiliary hydraulic chamber is allowed. And a communication state switching unit configured to switch the state of the sub hydraulic chamber.

In the piston device having the above-described configuration (1), in the communication-permitted state, the volume of the sub hydraulic chamber formed by the movable cylinder and the sub piston moving together with the main piston changes as the main piston or the sub piston reciprocates. In response to the volume change of the auxiliary hydraulic chamber, the auxiliary hydraulic fluid flows in and out of the auxiliary hydraulic chamber. In this case, the main piston does virtually no work.
On the other hand, in the communication restriction state in which the inflow and outflow of the auxiliary hydraulic oil from the auxiliary hydraulic chamber is restricted, the rigidity (system spring constant) of the hydraulic circuit including the auxiliary hydraulic chamber increases and acts on either the main piston or the auxiliary piston. The force is transmitted to the other of the main piston and the sub piston via the sub hydraulic oil in the sub hydraulic chamber, and the main piston and the sub piston move integrally. In this case, the main piston works according to the amount of oil displaced.
Therefore, according to the configuration of (1), the rigidity of the hydraulic circuit including the auxiliary hydraulic chamber is adjusted by switching the communication state of the auxiliary hydraulic chamber between the communication restricted state and the communication allowable state by the communication state switching unit. Thus, it is possible to select whether or not force is transmitted between the main piston and the sub piston (whether or not the main piston is allowed to work).

(2) In some embodiments, in the configuration of (1), the communication state switching unit includes an electromagnetic valve provided in a secondary oil line connected to the secondary hydraulic chamber.
According to the configuration of (2) above, the communication state of the sub hydraulic chamber can be switched by switching the solenoid of the solenoid valve between the excited state and the non-excited state. For this reason, it is possible to select whether or not to cause the main piston to work by switching the communication state of the sub hydraulic chamber and adjusting the rigidity of the hydraulic circuit including the sub hydraulic chamber with a simple configuration including the electromagnetic valve. .

(3) In some embodiments, in the configuration of the above (1) or (2), the maximum displacement volume of the main piston is larger than the maximum displacement volume of the sub-piston.
According to the configuration of (3) above, since the maximum displacement volume of the main piston is larger than the maximum displacement volume of the sub piston, the communication state in which the auxiliary hydraulic fluid circulates by switching the communication state of the sub hydraulic chamber. The capacity of the switching unit (for example, a solenoid valve) can be reduced. Therefore, while ensuring a large displacement volume of the piston device (a displacement volume of the main piston), the communication state switching unit can be reduced in size, and the piston device including the communication state switching unit can be reduced in size.
The reason why the maximum displacement of the sub piston can be made smaller than the maximum displacement of the main piston is as follows. In other words, the role of the auxiliary hydraulic chamber is to make it possible to select whether or not to cause the main piston to work by making a difference in the rigidity of the hydraulic circuit including the auxiliary hydraulic chamber between the communication allowed state and the communication restricted state. is there. For this reason, there is no restriction on the size of the sub hydraulic chamber, and the capacity of the sub hydraulic chamber (and the maximum displacement of the sub piston) can be made smaller than the maximum displacement of the main piston.

(4) In some embodiments, in any one of the configurations (1) to (3), a controller for controlling the communication state switching unit according to the phase of the sub piston is further provided.
According to the configuration of (4), the communication state switching unit can be controlled in accordance with the phase of the sub piston, so that the range of the phase of the sub piston that sets the sub hydraulic chamber to the communication restriction state can be set. Thus, the stroke of the main piston that moves together with the sub piston in the communication restricted state can be set to an intended value, and the displacement of the piston device can be arbitrarily adjusted.

(5) In some embodiments, in any one of the configurations (1) to (4), the movable cylinder is provided inside the main piston and concentrically with the main piston.
According to the configuration of (5) above, the movable cylinder is provided concentrically with the main piston inside the main piston, so that it is formed by the sub hydraulic chamber, the stationary cylinder and the main piston with respect to the main piston and the movable cylinder. The operating points of the hydraulic pressure acting from each of the main hydraulic chambers are aligned on the central axis of the main piston, and the moments are exerted on the main piston and the movable cylinder due to the hydraulic pressure received from the sub hydraulic chamber and the hydraulic pressure received from the main hydraulic chamber. No load is generated. For this reason, the sub piston can slide smoothly in the movable cylinder, and the transmission loss of energy between the sub piston and the main piston can be reduced.

(6) In some embodiments, in any one of the above configurations (1) to (5),
A high pressure line and a low pressure line respectively provided to communicate with a main hydraulic chamber formed by the stationary cylinder and the main piston;
A high-pressure valve provided in the high-pressure line;
A low pressure valve provided in the low pressure line,
At least one of the high pressure valve or the low pressure valve is a check valve.
In the above configuration (6), a check valve is used as a high-pressure valve or a low-pressure valve for switching the flow of hydraulic oil (hereinafter referred to as main hydraulic oil) between the high-pressure line and the low-pressure line and the main hydraulic chamber. . Therefore, with a simple configuration using a check valve, the reciprocating motion of the sub piston and the hydraulic energy of the main hydraulic chamber can be converted using the rigidity of the hydraulic circuit including the sub hydraulic chamber described above.

(7) In some embodiments, in any one of the configurations (1) to (6) above,
The piston device is a hydraulic pump unit configured to convert the reciprocating motion of the sub piston into pressure energy of a main hydraulic chamber formed by the stationary cylinder and the main piston,
A first urging member for urging the main piston in a direction from the top dead center to the bottom dead center of the main piston is further provided.
The rigidity of the hydraulic circuit including the auxiliary hydraulic chamber is smaller when the volume of the auxiliary hydraulic chamber increases (expansion stroke) than when the volume of the auxiliary hydraulic chamber decreases (compression stroke). For this reason, in the hydraulic pump unit, in the expansion stroke of the sub hydraulic chamber, since the rigidity of the hydraulic circuit including the sub hydraulic chamber is relatively small, the volume of the sub hydraulic chamber changes despite the communication restriction state. As a result, the displacement amount of the main piston becomes smaller than the displacement amount of the sub piston, and the main piston may not return to the bottom dead center.
According to the configuration of (7) above, since the first urging member for urging the main piston in the direction from the top dead center toward the bottom dead center is provided, the main piston and the sub piston reach the top dead center. After that, the main piston can be reliably moved to the bottom dead center by the urging force of the first urging member. Therefore, the operation of the hydraulic pump unit can be made smooth.

(8) In some embodiments, in any one of the configurations (1) to (6) above,
The piston device is a hydraulic motor unit configured to convert pressure energy of a main hydraulic chamber formed by the stationary cylinder and the main piston into a reciprocating motion of the sub piston,
A second urging member for urging the main piston in a direction from the bottom dead center to the top dead center of the main piston is further provided.
As described above, the rigidity of the hydraulic circuit including the auxiliary hydraulic chamber is smaller when the volume of the auxiliary hydraulic chamber increases (expansion stroke) than when the volume of the auxiliary hydraulic chamber decreases (compression stroke). For this reason, in the hydraulic motor unit, during the expansion stroke of the sub hydraulic chamber, the rigidity of the hydraulic circuit including the sub hydraulic chamber is relatively small, so that the volume of the sub hydraulic chamber changes despite the communication restriction state. As a result, the variable amount of the main piston becomes smaller than the displacement amount of the sub piston, and the main piston may not return to the top dead center.
According to the configuration of (8) above, since the second urging member for urging the main piston in the direction from the bottom dead center to the top dead center is provided, the main piston and the sub piston reach the bottom dead center. After that, the main piston can be reliably moved to the top dead center by the urging force of the second urging member. Therefore, the operation of the hydraulic motor unit can be made smooth.

(9) A hydraulic machine according to at least one embodiment of the present invention includes:
A rotation axis;
At least one piston device according to any one of (1) to (8) above;
An XY separation mechanism provided between the sub-piston and the rotary shaft of each piston device and configured to convert a motion mode between the reciprocating motion of the sub-piston and the rotary motion of the rotary shaft. And comprising.

  According to the configuration of (9) above, the force transmitted in the XY separation mechanism from the rotating shaft toward the sub piston is separated into the movable cylinder axis direction component (X direction component) and the movable cylinder axis orthogonal component (Y direction component). Therefore, only the force of the movable cylinder axial direction component (X direction component) is transmitted to the auxiliary piston. Therefore, the side force acting on the sub piston from the XY separation mechanism provided between the rotating shaft and the sub piston can be reduced. Therefore, generation of friction, wear, and heat generation of the sub-piston or the movable cylinder on which the sub-piston slides due to side force can be suppressed, and reciprocation and rotation along the cylinder axis direction (X direction) of the sub-piston. It is possible to increase the efficiency of motion mode conversion between the rotational motion of the shaft and extend the life of the auxiliary piston.

(10) A hydraulic machine according to at least one embodiment of the present invention includes:
A rotation axis;
A plurality of piston devices according to any one of the above (1) to (8);
A controller for controlling the communication state switching unit of each of the piston devices,
The controller is configured to be able to control the communication state switching unit independently of each other for each of the plurality of piston devices.

  According to the configuration of (10), since the communication state switching unit can be controlled independently of each other for each of the plurality of piston devices constituting the hydraulic machine, the displacement volume as a whole of the hydraulic machine is finely adjusted. be able to.

  According to at least one embodiment of the present invention, a piston device is provided that operates on a different principle.

It is a figure which shows the electric power generating apparatus provided with the hydraulic machine which concerns on one Embodiment. It is a figure showing the outline of the composition of the hydraulic machine concerning one embodiment. It is a figure which shows the outline of a structure of the piston apparatus (hydraulic pump unit) which concerns on one Embodiment. It is a figure which shows the outline of a structure of the piston apparatus (hydraulic motor unit) which concerns on one Embodiment. It is a figure for demonstrating the working principle of the piston apparatus which concerns on one Embodiment. It is a figure for demonstrating the working principle of the piston apparatus which concerns on one Embodiment. It is a figure showing the outline of the composition of the hydraulic machine concerning one embodiment.

  Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described in the embodiments or shown in the drawings are not intended to limit the scope of the present invention, but are merely illustrative examples. Absent.

  In the following embodiments, a power generation device will be described as an example of a device including a hydraulic machine according to an embodiment.

  FIG. 1 is a diagram illustrating a power generation device including a hydraulic machine according to an embodiment. As shown in the figure, the power generator 1 includes a prime mover 2, a hydraulic transmission 4 connected to the prime mover 2 via a rotary shaft 3, and a generator 6 connected to the hydraulic transmission 4 via a rotary shaft 5. Is provided.

In one embodiment, the hydraulic transmission 4 includes a hydraulic pump 8 that is coupled to the prime mover 2 via the rotating shaft 3 and a hydraulic motor 10 that is coupled to the generator 6 via the rotating shaft 5. The hydraulic pump 8 and the hydraulic motor 10 are connected to each other via a high pressure oil line 12 and a low pressure oil line 14. Specifically, the outlet of the hydraulic pump 8 is connected to the inlet of the hydraulic motor 10 via the high-pressure oil line 12, and the inlet of the hydraulic pump 8 is connected to the outlet of the hydraulic motor 10 via the low-pressure oil line 14. The hydraulic pump 8 is driven by the rotary shaft 3 to increase the pressure of the hydraulic oil and generate high-pressure hydraulic oil (pressure oil). The pressure oil generated by the hydraulic pump 8 is supplied to the hydraulic motor 10 via the high-pressure oil line 12, and the hydraulic motor 10 is driven by this pressure oil. The low-pressure hydraulic oil after the work is performed by the hydraulic motor 10 is returned again to the hydraulic pump 8 via the low-pressure oil line 14 provided between the outlet of the hydraulic motor 10 and the inlet of the hydraulic pump 8.
In some embodiments, at least one of the hydraulic pump 8 or the hydraulic motor 10 is a hydraulic machine with a piston device described below. In this case, the high-pressure oil line 12 and the low-pressure oil line 14 may be a high-pressure line 26 and a low-pressure line 28 in the piston device 30 described later.

  FIG. 2 is a diagram illustrating a schematic configuration of a hydraulic machine including a piston device according to an embodiment. FIGS. 3 and 4 are diagrams illustrating a schematic configuration of the piston device according to the embodiment, respectively. is there. The piston devices shown in FIGS. 3 and 4 are a hydraulic pump unit and a hydraulic motor unit, respectively.

  As shown in FIG. 2, a hydraulic machine 20 according to an embodiment includes a rotating shaft 22 (crankshaft in FIG. 2), at least one (two in FIG. 2) piston device 30, and a rotating shaft 22. And a conversion mechanism 24 provided between the piston device 30 and the piston device 30. The conversion mechanism 24 is a mechanism for performing conversion between the rotational motion of the rotary shaft 22 and the reciprocating motion of a sub piston 38 (described later) in the piston device 30.

In the hydraulic machine 20 shown in FIG. 2, the conversion mechanism 24 includes an XY separation mechanism described later.
In some embodiments, the conversion mechanism 24 may include a cam that is attached to the rotary shaft 22 and has a cam curved surface that abuts against the secondary piston 38 of the piston device 30. Such a cam may be an eccentric cam provided eccentric from the axial center of the rotating shaft (crankshaft) 22 or may be an annular multi-lobe cam having a plurality of lobes.

The two piston devices 30 included in the hydraulic machine 20 of FIG. 2 are both hydraulic pump units 16 described later. Each hydraulic pump unit 16 includes a high-pressure line 26 and a low-pressure line 28. The hydraulic pump unit 16 is driven from the rotary shaft 22 via the conversion mechanism 24 described above, and supplies hydraulic oil (main hydraulic oil) supplied from the low-pressure line 28. The pressure is increased and discharged to the high-pressure line 26.
The hydraulic machine 20 includes a main hydraulic oil tank 25 for storing main hydraulic oil supplied to the hydraulic pump unit 16, and an oil supply line 29 that connects the low-pressure line 28 and the main hydraulic oil tank 25. The hydraulic machine 20 includes a high-pressure oil delivery line 27 that is connected to the high-pressure line 26 and sends out the main hydraulic fluid that has been pressurized by the hydraulic pump unit 16 to the outside.
Further, the hydraulic machine 20 includes a controller 90 for controlling a communication state switching unit 60 (described later) of each hydraulic pump unit 16 and a rotation sensor (phase) for measuring the rotation angle of the rotary shaft (crankshaft) 22. Sensor) 92.
In one embodiment, the controller 90 may be configured to control the communication state switching unit 60 of each hydraulic pump unit 16 based on the measurement result of the rotation sensor (phase sensor) 92.

As shown in FIGS. 3 and 4, the piston device 30 according to the embodiment includes a stationary cylinder 32, a main piston 34, a movable cylinder 36, a sub piston 38, and a communication state switching unit 60.
The main piston 34 is provided in the stationary cylinder 32 so as to be able to reciprocate, and forms a main hydraulic chamber 40 together with the inner wall surface 33 of the stationary cylinder 32.
The movable cylinder 36 is configured to move with the main piston 34. In the piston device 30 shown in FIGS. 3 and 4, the movable cylinder 36 is provided concentrically with the main piston 34 inside the main piston 34. That is, the movable cylinder 36 and the main piston 34 are integrated, and the movable cylinder 36 moves together with the main piston 34.
The sub-piston 38 is provided so as to be capable of reciprocating in the movable cylinder 36 and forms a sub-hydraulic chamber 42 together with the inner wall surface 37 of the movable cylinder 36.
The communication state switching unit 60 includes a communication restriction state in which the inflow / outflow of the auxiliary hydraulic oil from the auxiliary hydraulic chamber 42 is restricted, and a communication allowable state in which the inflow / outflow of the auxiliary hydraulic oil from the auxiliary hydraulic chamber 42 is allowed. The auxiliary hydraulic chamber 42 is configured to switch the state.

  The communication state switching unit 60 will be described in more detail. The piston device 30 shown in FIGS. 3 and 4 further includes a sub hydraulic oil tank 58 for storing the sub hydraulic oil, and a sub oil line 56 that connects the sub hydraulic oil tank 58 and the sub hydraulic chamber 42. The auxiliary hydraulic chamber 42 and the auxiliary oil line 56 are connected via a movable passage 54 provided in the movable cylinder 36, and an oil groove 50 and a stationary passage 52 provided in the stationary cylinder 32.

  A movable passage 54 provided in the movable cylinder 36 (the same body as the main piston 34 in FIGS. 3 and 4) is an outer peripheral surface of the movable cylinder 36 (main piston 34) and an inner wall surface 37 of the movable cylinder forming the auxiliary hydraulic chamber 42. It is provided so that it may open to both. The movable passage 54 is provided in the vicinity of the bottom 39 of the inner wall surface 37 of the movable cylinder 36 facing the sub piston 38 in the axial direction in the movable cylinder axial direction. By providing the movable passage 54 in the vicinity of the bottom 39, the main piston 34 and the sub-piston 38 on the side of the sub-hydraulic chamber 42 in the movable passage 54 over the entire period in which the main piston 34 and the sub-piston 38 reciprocate between the bottom dead center and the top dead center. The opening of the movable passage 54 can be maintained in the auxiliary hydraulic chamber 42 without the opening being blocked by the auxiliary piston 38. For example, even when the volume of the sub hydraulic chamber 42 is reduced, such as when the sub piston 38 is positioned near the top dead center and the main piston 34 is positioned near the bottom dead center, the movable passage 54 is connected to the sub hydraulic chamber 42. The opening state can be maintained.

The oil groove 50 is a groove formed in the inner wall surface 37 of the stationary cylinder 32, and the movable passage 54 is located at least when the main piston 34 reciprocates in the stationary cylinder 32 in the axial direction of the stationary cylinder 32. It is formed so as to extend over a range and to extend to at least a part of the range in which the movable passage 54 exists in the circumferential direction of the stationary cylinder 32. Thereby, the state which the oil groove 50 and the movable channel | path 54 connected can be maintained in the whole period when the main piston 34 reciprocates between a bottom dead center and a top dead center.
The oil groove 50 may be a groove formed in a part of the stationary cylinder 32 in the circumferential direction, or may be an annular groove formed continuously over the entire circumference in the circumferential direction.
The stationary passage 52 is formed in the stationary cylinder 32 so as to open to the oil groove 50 on the outer peripheral side of the oil groove 50, and connects the oil groove 50 and the auxiliary oil line 56.

  The auxiliary hydraulic oil can flow in and out between the auxiliary hydraulic chamber 42 and the auxiliary oil line 56 through the above-described movable passage 54, oil groove 50 and stationary passage 52.

  In the piston device 30 shown in FIGS. 3 and 4, the auxiliary oil line 56 is provided with an electromagnetic valve 61 as a communication state switching unit 60. The state of the sub hydraulic chamber 42 can be switched between the communication restricted state and the communication permitted state in accordance with the open / closed state of the electromagnetic valve 61.

For example, by closing the solenoid valve 61, the inflow of the auxiliary hydraulic oil from the auxiliary oil line 56 to the auxiliary hydraulic chamber 42 and the outflow of the auxiliary hydraulic oil from the auxiliary hydraulic chamber 42 to the auxiliary oil line 56 are regulated. The sub hydraulic chamber 42 enters the communication restriction state. Further, by opening the electromagnetic valve 61, the inflow of the auxiliary hydraulic oil from the auxiliary oil line 56 to the auxiliary hydraulic chamber 42 and the outflow of the auxiliary hydraulic oil from the auxiliary hydraulic chamber 42 to the auxiliary oil line 56 are permitted. The sub hydraulic chamber 42 is in a communication-permitted state.
As will be described later, the communication state switching unit 60 such as the electromagnetic valve 61 switches the communication state of the sub hydraulic chamber 42 between the communication restriction state and the communication permissible state, thereby improving the rigidity of the hydraulic circuit including the sub hydraulic chamber 42. By adjusting, it is possible to select whether or not to cause the main piston 34 to work.

The piston device 30 includes a high pressure line 26 and a low pressure line 28 provided so as to communicate with the main hydraulic chamber 40, a high pressure valve 46 provided on the high pressure line 26, and a low pressure valve 48 provided on the low pressure line 28. Further prepare.
Inside the stationary cylinder 32, a high pressure communication path 43 for communicating the main hydraulic chamber 40 and the high pressure line 26 via the high pressure valve 46, and the main hydraulic chamber 40 and the low pressure line 28 via the low pressure valve 48. Is provided with a low-pressure communication passage 44.
In some embodiments, at least one of the high pressure valve 46 or the low pressure valve 48 is a check valve.

  The piston device 30 shown in FIG. 3 is the piston device 30 included in the hydraulic machine 20 shown in FIG. 2, and the reciprocating motion of the sub piston 38 is caused by the pressure of the main hydraulic chamber 40 formed by the stationary cylinder 32 and the main piston 34. A hydraulic pump unit 16 configured to convert to energy. In the hydraulic pump unit 16, the high pressure valve 46A provided in the high pressure line 26 and the low pressure valve 48A provided in the low pressure line 28 are check valves, respectively. The hydraulic pump unit 16 further includes a first biasing member 62 (a spring in FIG. 3) for biasing the main piston 34 in a direction from the top dead center to the bottom dead center. .

In the piston device 30 (hydraulic pump unit 16) shown in FIG. 3, the rotating shaft (crankshaft) 22 (see FIG. 2) rotates by a power source (not shown), and the rotating motion of the rotating shaft 22 is converted into a conversion mechanism 24. Is converted into a reciprocating motion of the auxiliary piston 38. That is, the sub piston 38 reciprocates within the movable cylinder 36 in accordance with the rotation of the rotating shaft 22.
When the communication state of the sub hydraulic chamber 42 is the communication restriction state (that is, when the solenoid valve 61 is closed and the flow of sub hydraulic oil from the sub hydraulic chamber 42 is restricted). The main piston 34 reciprocates between the bottom dead center and the top dead center in the stationary cylinder 32 as the sub piston 38 reciprocates.

In the hydraulic pump unit 16, the relationship between the opening / closing operation of the high pressure valve 46 </ b> A and the low pressure valve 48 </ b> A and the flow of main hydraulic oil in and out of the main hydraulic chamber 40 is as follows.
In the expansion stroke (intake stroke) in which the main piston 34 moves from the top dead center to the bottom dead center, the volume of the main hydraulic chamber 40 increases and the pressure in the main hydraulic chamber 40 decreases as the main piston 34 moves. To do. When the pressure in the main hydraulic chamber 40 becomes lower than the pressure in the low pressure line 28, the low pressure valve 48 </ b> A that is a check valve opens, and low pressure main hydraulic oil flows into the main hydraulic chamber 40 from the low pressure line 28. When the main piston 34 reaches near the bottom dead center, the pressure in the main hydraulic chamber 40 and the pressure in the low pressure line 28 become substantially equal, and the low pressure valve 48A is closed.
In the compression stroke (discharge stroke) in which the main piston 34 moves from the bottom dead center to the top dead center, the volume of the main hydraulic chamber decreases as the main piston 34 moves, and the main hydraulic oil is pressurized. When the pressure in the main hydraulic chamber 40 becomes higher than the pressure in the high pressure line 26, the high pressure valve 46A, which is a check valve, opens, and the main hydraulic oil that has become high pressure flows from the main hydraulic chamber 40 to the high pressure line 26. To do. When the main piston 34 reaches near the top dead center, the pressure in the main hydraulic chamber 40 and the pressure in the high pressure line 26 become substantially equal, and the high pressure valve 46A closes.
Thus, in the hydraulic pump unit 16, the main hydraulic oil flows from the low pressure line 28 into the main hydraulic chamber 40 as the main piston 34 reciprocates, and the main hydraulic oil is pressurized in the main hydraulic chamber 40. The pressurized main hydraulic oil is sent out to the high-pressure line 26.

  In addition, as a high-pressure valve 46A provided in the high-pressure line 26 of the hydraulic pump unit 16 and a low-pressure valve 48A provided in the low-pressure line 28, a valve (for example, an electronic control valve) that can be actively controlled is used instead of the check valve. Then, the flow of main hydraulic oil from the main hydraulic chamber 40 may be controlled by actively controlling the opening and closing of these valves.

  In the hydraulic pump unit 16, the main piston 34 and the sub piston 38 reach the top dead center by the first biasing member 62 for biasing the main piston 34 in the direction from the top dead center toward the bottom dead center. Later, the main piston 34 can be reliably moved to the bottom dead center by the biasing force of the first biasing member 62. Therefore, the operation of the hydraulic pump unit 16 can be made smooth.

  The piston device 30 shown in FIG. 4 is a hydraulic motor unit 18 configured to convert the pressure energy of the main hydraulic chamber 40 formed by the stationary cylinder 32 and the main piston 34 into the reciprocating motion of the sub piston 38. In the piston device 30 (hydraulic motor unit), the high-pressure valve 46B provided in the high-pressure line 26 and the low-pressure valve 48B provided in the low-pressure line 28 are valves (for example, electronic control valves) that can be actively controlled. The hydraulic motor unit 18 further includes a second urging member 63 (a spring in FIG. 4) for urging the main piston 34 in a direction from the bottom dead center to the top dead center.

The hydraulic motor unit 18 shown in FIG. 4 can constitute, for example, the hydraulic machine 20 shown in FIG. 2, similarly to the hydraulic pump unit 16 described above. In this case, the sub piston 38 of the hydraulic motor unit 18 and the rotary shaft 22 (for example, a crankshaft) are connected via the conversion mechanism 24.
In the hydraulic motor unit 18, the main piston 34 reciprocates in the stationary cylinder 32 by receiving a force from high-pressure oil (main hydraulic oil) flowing into the main hydraulic chamber 40. When the communication state of the sub hydraulic chamber 42 is the communication restriction state (that is, when the solenoid valve 61 is closed and the flow of sub hydraulic oil from the sub hydraulic chamber 42 is restricted). The sub piston 38 reciprocates in the movable cylinder 36 as the main piston 34 reciprocates. Then, the reciprocating motion of the sub piston 38 is converted into the rotational motion of the rotating shaft 22 by the converting mechanism 24.

In the hydraulic motor unit 18, the relationship between the opening / closing operation of the high pressure valve 46 </ b> B and the low pressure valve 48 </ b> B and the flow of main hydraulic oil in and out of the main hydraulic chamber 40 is as follows.
In the expansion stroke (suction stroke) in which the main piston 34 moves from the top dead center to the bottom dead center, the high pressure valve 46B is opened by active control, and the high pressure main hydraulic oil is supplied from the high pressure line 26 to the main hydraulic chamber 40. The main piston 34 receives the force from the main hydraulic oil and moves toward the bottom dead center. When the main piston 34 reaches near the bottom dead center, the high-pressure valve 46B is closed by active control, and no more main hydraulic oil is supplied into the main hydraulic chamber 40.
Next, in the compression stroke (discharge stroke) in which the main piston 34 moves from the bottom dead center toward the top dead center, the low pressure valve 48B is opened by active control to perform work on the main piston 34. Thus, the main hydraulic oil whose pressure has been reduced is discharged from the main hydraulic chamber 40 to the low pressure line 28. When the main piston 34 reaches the vicinity of the top dead center, the low pressure valve 48B is closed, and the main hydraulic oil is no longer discharged from the main hydraulic chamber 40 to the low pressure line 28.
In this manner, in the hydraulic motor unit 18, the main hydraulic oil flows into the main hydraulic chamber 40 from the high pressure line 26 as the main piston 34 reciprocates, and the main hydraulic oil performs work in the main hydraulic chamber 40. As a result, the pressure of the main hydraulic oil is reduced, and the main hydraulic oil whose pressure has been reduced is sent out to the low pressure line 28.

  Note that, as the low pressure valve 48B provided in the low pressure line 28 of the hydraulic motor unit 18, a check valve is used instead of the actively controllable valve to control the outflow of the main hydraulic oil from the main hydraulic chamber 40. May be.

  In the hydraulic motor unit 18, the main piston 34 and the sub piston 38 have reached the bottom dead center by the second biasing member 63 for biasing the main piston 34 in the direction from the bottom dead center toward the top dead center. Later, the main piston 34 can be reliably moved to the bottom dead center by the urging force of the second urging member 63. Therefore, the operation of the hydraulic motor unit 18 can be made smooth.

In the piston device 30 having the above-described configuration, as described above, the communication state switching unit 60 such as the electromagnetic valve 61 switches the communication state of the auxiliary hydraulic chamber 42 between the communication restricted state and the communication permitted state, and the auxiliary hydraulic pressure. By adjusting the rigidity of the hydraulic circuit including the chamber 42, it is possible to select whether or not to cause the main piston 34 to work. This will be described with reference to FIGS. 5 and 6 are diagrams for explaining the operating principle of the piston device according to the embodiment.
In the following, the operation principle of the hydraulic pump unit 16 described above will be described as an example of the piston device 30, but the operation principle of other piston devices 30 including the hydraulic motor unit 18 can be described in the same manner.

  FIG. 5 is a diagram illustrating an operation example of the main piston 34 when the communication state of the auxiliary hydraulic chamber 42 is the communication restriction state. FIG. 5A is a view when the main piston 34 is located at the bottom dead center. FIG. 5B shows the piston device 30 when the main piston 34 is located at the top dead center.

  In the piston device 30, in the communication restriction state in which the solenoid valve 61 is closed and the inflow / outflow of the auxiliary hydraulic oil from the auxiliary hydraulic chamber 42 is restricted, the rigidity (system spring constant) of the hydraulic circuit including the auxiliary hydraulic chamber 42 is low. The force acting on one of the main piston 34 or the sub piston 38 is increased and transmitted to the other of the main piston 34 or the sub piston 38 via the sub hydraulic oil in the sub hydraulic chamber 42, and the main piston 34 and the sub piston 38. Move together.

  For example, as shown in FIG. 5A, when the main piston 34 of the hydraulic pump unit 16 is located at the bottom dead center and the sub piston 38 is located at the bottom dead center, the electromagnetic valve 61 is in the closed state. Thus, when the state of the auxiliary hydraulic chamber 42 becomes the communication restricted state, the rigidity of the hydraulic circuit including the auxiliary hydraulic chamber 42 increases. For this reason, when the sub piston 38 tries to move from the bottom dead center (BDC_S) of the sub piston 38 toward the top dead center (TDC_S) as the rotary shaft 22 rotates, the force acting on the sub piston 38 is sub hydraulic pressure. It is transmitted to the main piston 34 via the auxiliary hydraulic oil in the chamber 42. For this reason, the main piston 34 moves from the bottom dead center (BDC_M) of the main piston toward the top dead center (TDC_M) integrally with the sub piston 38, and as shown in FIG. 38 and the main piston 34 both reach the bottom dead center (BDC_S, BDC_M). Thus, in the process of moving the main piston 34 from the bottom dead center to the top dead center, the main piston 34 pressurizes the main hydraulic oil in the main hydraulic chamber 40 and discharges it to the high pressure line 26. That is, the main piston 34 performs work according to the amount of main hydraulic oil displaced from the main hydraulic chamber 40.

  On the other hand, FIG. 6 is a view showing an operation example of the main piston 34 when the communication state of the sub hydraulic chamber 42 is a communication permission state. FIG. 6A shows the sub piston 38 located at the bottom dead center. FIG. 6B shows the piston device 30 when the sub piston 38 is located at the top dead center.

  In the piston device 30, when the solenoid valve 61 is in an open state and the communication permitting state in which the inflow / outflow of the sub working oil from the sub hydraulic chamber 42 is permitted, the main piston 34 or the sub piston 38 reciprocates, The volume of the sub hydraulic chamber 42 formed by the movable cylinder 36 that moves together with the sub piston 38 changes, and the sub hydraulic oil flows in and out of the sub hydraulic chamber 42 in response to the volume change of the sub hydraulic chamber 42.

  For example, as shown in FIG. 6A, when the main piston 34 of the hydraulic pump unit 16 is located at the bottom dead center and the sub piston 38 is located at the bottom dead center, the electromagnetic valve 61 is opened. When the state of the auxiliary hydraulic chamber 42 is in the communication-permitted state, the auxiliary hydraulic oil can freely flow in and out of the auxiliary hydraulic chamber 42 via the auxiliary oil line 56 and the electromagnetic valve 61. For this reason, the volume of the sub hydraulic chamber 42 changes with the reciprocating motion between the bottom dead center (BDC_S) and the top dead center (TDC_S) of the sub piston 38, corresponding to the volume change of the sub hydraulic chamber 42. As a result, the auxiliary hydraulic fluid flows in and out of the auxiliary hydraulic chamber 42. On the other hand, since the force acting on the sub piston 38 is not transmitted to the main piston 34 via the sub hydraulic oil in the sub hydraulic chamber 42, the movable cylinder 36 and the main piston 34 do not reciprocate within the stationary cylinder 32. Therefore, as shown in FIG. 6B, even if the sub piston 38 moves to the top dead center (TDC_S), the main piston 34 remains at the bottom dead center (TDC_M). That is, the main piston 34 does substantially no work.

  Therefore, in the piston device 30, the communication state switching unit 60 such as the electromagnetic valve 61 or the like switches the communication state of the sub hydraulic chamber 42 between the communication restriction state and the communication permissible state, thereby improving the rigidity of the hydraulic circuit including the sub hydraulic chamber 42. By adjusting, it is possible to select whether or not to cause the main piston 34 to work.

In some embodiments, the piston device 30 such as the hydraulic pump unit 16 or the hydraulic motor unit 18 is configured with a controller 90 (for controlling the communication state switching unit 60 (for example, the electromagnetic valve 61) according to the phase of the sub piston 38). 2).
In this case, since the communication state switching unit 60 (for example, the electromagnetic valve 61) can be controlled according to the phase of the sub piston 38 using the controller 90, the phase of the sub piston 38 that places the sub hydraulic chamber 42 in the communication restriction state is controlled. The range can be arbitrarily set between the bottom dead center and the top dead center. Thereby, the stroke of the main piston 34 that moves together with the sub piston 38 in the communication restricted state can be set to an intended value, and the displacement volume of the piston device 30 can be arbitrarily adjusted.
The phase of the sub-piston 38 may be obtained by a sensor (not shown) for measuring the position of the sub-piston 38, or a rotation sensor for measuring the phase of the rotary shaft 22 (rotation in FIG. 2). (See sensor 92).

Further, in some embodiments, in the piston device 30, the maximum displacement volume of the main piston 34 is larger than the maximum displacement volume of the sub piston 38.
Since the maximum displacement volume of the main piston 34 is larger than the maximum displacement volume of the sub-piston 38, the communication state switching unit 60 (for example, the solenoid valve 61) in which the sub hydraulic fluid flows by switching the communication state of the sub hydraulic chamber 42. ) Capacity can be reduced. Therefore, while ensuring a large displacement volume of the piston device 30 (a displacement volume by the main piston 34), the communication state switching unit 60 can be reduced in size, and the piston device 30 including the communication state switching unit 60 can be reduced in size. .
For example, if a small solenoid valve 61 is used as the communication state switching unit 60, the solenoid valve 61 itself is small, and the current required for opening / closing control of the solenoid valve 61 is small. It becomes possible. For this reason, the piston apparatus 30 which can respond to a larger rotation speed can be obtained.

  In the piston device 30 shown in FIGS. 3 and 4, as described above, the movable cylinder 36 is provided concentrically with the main piston 34 inside the main piston 34. As a result, the action points of the hydraulic pressure acting from the sub hydraulic chamber 42 and the main hydraulic chamber 40 on the main piston 34 and the movable cylinder 36 are aligned on the central axis of the main piston 34. Therefore, no moment load is generated in the main piston 34 and the movable cylinder 36 due to the hydraulic pressure received from the sub hydraulic chamber 42 and the hydraulic pressure received from the main hydraulic chamber 40. For this reason, the sub piston 38 can slide smoothly in the movable cylinder 36, and the transmission loss of energy between the sub piston 38 and the main piston 34 can be reduced.

  FIG. 7 is a diagram illustrating a schematic configuration of a hydraulic machine according to an embodiment. A hydraulic machine 20 illustrated in FIG. 7 includes a rotary shaft 22, the hydraulic pump unit 16 that is the piston device 30 described above, and an XY separation mechanism 23 as a conversion mechanism 24. The XY separation mechanism 23 is provided between the sub piston 38 of the hydraulic pump unit 16 and the rotary shaft 22, and is configured to convert a motion mode between the reciprocating motion of the sub piston 38 and the rotary motion of the rotary shaft 22. Is done.

  The XY separation mechanism 23 includes a moving part 64 supported by the stationary part 21 of the hydraulic machine 20, an intermediate part 68 provided between the sub piston 38 and the moving part 64, and between the intermediate part 68 and the moving part 64. And a slide portion 70 provided on the head.

The moving unit 64 is connected to the rotary shaft 22 via the crank mechanism 72. The crank mechanism 72 includes a crank arm 74 having one end connected to the rotary shaft 22 and a crank pin 73 for connecting the other end of the crank arm 74 to the moving unit 64.
The moving unit 64 connected to the rotary shaft 22 via the crank mechanism 72 has an X-direction component in the movable cylinder axis direction and a Y-direction component in the movable cylinder axis orthogonal direction in a plane orthogonal to the axial direction of the rotary shaft 22. The synthesized velocity vector V moves in conjunction with the rotation of the rotary shaft 22. That is, with the rotation of the rotating shaft 22, the crank pin 73 moves around the axis center of the rotating shaft 22 so as to draw a locus 81. Here, the trajectory 81 is a circle centered on the rotating shaft 22 whose radius is the length of the crank arm 74 (distance between the rotating shaft 22 and the crank pin 73). Therefore, the moving unit 64 connected to the crankpin 73 moves in conjunction with the rotation of the rotating shaft 22 at the speed vector V in a plane orthogonal to the axial direction of the rotating shaft 22 as the crankpin 73 moves. become.

  The motion mode is converted between the reciprocating motion of the sub piston 38 along the movable cylinder axis direction and the rotational motion of the rotary shaft 22 by the XY separation mechanism 23 including the moving portion 64, the intermediate portion 68, and the slide portion 70 described above. The

The moving unit 64 is supported by the stationary unit 21 via a first slider 76 and a second slider 78 provided between the moving unit 64 and the stationary unit 21. The first slider 76 allows the moving part 64 to move freely in the direction of the movable cylinder axis, and the second slider 78 allows the moving part 64 to move freely in the direction perpendicular to the movable cylinder axis.
Thus, the first slider 76 and the second slider 78 allow the moving unit 64 to move in the movable cylinder axis direction and the movable cylinder axis orthogonal direction in a plane orthogonal to the axial direction of the rotating shaft 22. Accordingly, the moving unit 64 moves in a plane orthogonal to the axial direction of the rotary shaft 22 in conjunction with the rotation of the rotary shaft 22 while being supported by the stationary portion 21 via the first slider 76 and the second slider 78. Can do.

The slide unit 70 supports the intermediate unit 68 on the moving unit 64 so as to be movable in the direction perpendicular to the movable cylinder axis relative to the moving unit 64.
In the embodiment shown in FIG. 7, both the slide part 70 and the second slider 78 play a role in one slider member disposed between the moving part 64 and the intermediate part 68.

  The stationary part 21 is a member that is fixed and stationary in the hydraulic machine 20. For example, a cylinder block surrounding the stationary cylinder 32 or a member connected so as to be fixed to the cylinder block can be used as the stationary portion 21.

  In the hydraulic machine 20 shown in FIG. 7, the intermediate portion 68 positioned between the moving portion 64 interlocked with the rotating shaft 22 and the sub piston 38 is moved by the slide portion 70 in the direction perpendicular to the movable cylinder axis. Is supported by the moving portion 64 so as to be relatively movable. For this reason, the force transmitted from the XY separation mechanism 23 to the sub piston 38 is basically only a component along the movable cylinder axis direction. That is, the force transmitted from the rotary shaft 22 toward the sub piston 38 in the XY separation mechanism 23 is separated into a movable cylinder axis direction component (X direction component) and a movable cylinder axis orthogonal component (Y direction component) in the slide portion 70. Therefore, only the force of the movable cylinder axial direction component (X direction component) is transmitted to the auxiliary piston 38 from the slide portion 70 via the intermediate portion 68. Therefore, the side force acting on the sub piston 38 from the XY separation mechanism 23 provided between the rotating shaft 22 and the sub piston 38 can be reduced.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to embodiment mentioned above, The form which added the deformation | transformation to embodiment mentioned above and the form which combined these forms suitably are included.

In this specification, an expression representing a relative or absolute arrangement such as “in a certain direction”, “along a certain direction”, “parallel”, “orthogonal”, “center”, “concentric” or “coaxial”. Represents not only such an arrangement strictly but also a state of relative displacement with tolerance or an angle or a distance to obtain the same function.
For example, an expression indicating that things such as “identical”, “equal”, and “homogeneous” are in an equal state not only represents an exactly equal state, but also has a tolerance or a difference that can provide the same function. It also represents the existing state.
In this specification, expressions representing shapes such as quadrangular shapes and cylindrical shapes not only represent shapes such as quadrangular shapes and cylindrical shapes in a strict geometric sense, but also within a range where the same effects can be obtained. In addition, a shape including an uneven portion or a chamfered portion is also expressed.
In this specification, the expression “comprising”, “including”, or “having” one constituent element is not an exclusive expression for excluding the existence of another constituent element.

DESCRIPTION OF SYMBOLS 1 Power generator 2 Motor | power_engine 3 Rotating shaft 4 Hydraulic transmission 5 Rotating shaft 6 Generator 8 Hydraulic pump 10 Hydraulic motor 12 High pressure oil line 14 Low pressure oil line 16 Hydraulic pump unit 18 Hydraulic motor unit 20 Hydraulic machine 21 Stationary part 22 Rotating shaft 23 XY Separation mechanism 24 Conversion mechanism 25 Main hydraulic oil tank 26 High pressure line 27 High pressure oil delivery line 28 Low pressure line 29 Oil supply line 30 Piston device 32 Stationary cylinder 33 Inner wall surface 34 Main piston 36 Movable cylinder 37 Inner wall surface 38 Sub piston 39 Bottom 40 Main Hydraulic chamber 42 Sub-hydraulic chamber 43 High-pressure communication passage 44 Low-pressure communication passage 46 High-pressure valve 48 Low-pressure valve 50 Oil groove 52 Static passage 54 Movable passage 56 Sub-oil line 58 Sub-operating oil tank 60 Communication state switching unit 61 Electromagnetic valve 62 First attachment Force member 63 Second bias member 64 Moving portion 68 Intermediate part 70 Slide part 72 Crank mechanism 73 Crank pin 74 Crank arm 76 First slider 78 Second slider 81 Trajectory 90 Controller 92 Rotation sensor

Claims (10)

A stationary cylinder;
A main piston provided in the stationary cylinder so as to be capable of reciprocating;
A movable cylinder configured to move with the main piston;
A sub-piston provided in the movable cylinder so as to be capable of reciprocating;
A communication restriction state in which the inflow and outflow of the auxiliary hydraulic oil from the auxiliary hydraulic chamber formed by the movable cylinder and the auxiliary piston is restricted, and the communication permission in which the inflow and inflow of the auxiliary hydraulic oil from the auxiliary hydraulic chamber is allowed. A communication state switching unit configured to switch the state of the sub hydraulic chamber in a state, and
A piston device comprising:   2. The piston device according to claim 1, wherein the communication state switching unit includes an electromagnetic valve provided in a secondary oil line connected to the secondary hydraulic chamber.   The piston device according to claim 1 or 2, wherein a maximum displacement volume of the main piston is larger than a maximum displacement volume of the sub piston.   The piston device according to any one of claims 1 to 3, further comprising a controller for controlling the communication state switching unit in accordance with a phase of the sub piston.   5. The piston device according to claim 1, wherein the movable cylinder is provided concentrically with the main piston inside the main piston. 6. A high pressure line and a low pressure line respectively provided to communicate with a main hydraulic chamber formed by the stationary cylinder and the main piston;
A high-pressure valve provided in the high-pressure line;
A low pressure valve provided in the low pressure line,
6. The piston device according to claim 1, wherein at least one of the high-pressure valve and the low-pressure valve is a check valve. The piston device is a hydraulic pump unit configured to convert the reciprocating motion of the sub piston into pressure energy of a main hydraulic chamber formed by the stationary cylinder and the main piston,
The piston device according to claim 1, further comprising a first urging member for urging the main piston in a direction from a top dead center to a bottom dead center of the main piston. The piston device is a hydraulic motor unit configured to convert pressure energy of a main hydraulic chamber formed by the stationary cylinder and the main piston into a reciprocating motion of the sub piston,
The piston device according to claim 1, further comprising a second urging member for urging the main piston in a direction from the bottom dead center to the top dead center of the main piston. A rotation axis;
At least one piston device according to any one of claims 1 to 8,
An XY separation mechanism provided between the sub-piston and the rotary shaft of each piston device and configured to convert a motion mode between the reciprocating motion of the sub-piston and the rotary motion of the rotary shaft. And a hydraulic machine. A rotation axis;
A plurality of piston devices according to any one of claims 1 to 8;
A controller for controlling the communication state switching unit of each of the piston devices,
The controller is configured to be capable of independently controlling the communication state switching unit for each of the plurality of piston devices.

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