JP4704259B2 - Energy converter - Google Patents

Description

  The present invention relates to an energy conversion device that drives a fluid pressure motor using inertial energy and potential energy of an actuator and rotates a generator by the rotational force of the fluid pressure motor.

As this type of apparatus, an apparatus described in Patent Document 1 has been conventionally known. This conventional apparatus is provided with a switching valve that switches on and off in a return path when inertial energy or potential energy acts on the actuator. When the switching valve is in the normal position, the return fluid of the actuator to which inertia energy or potential energy has acted returns to the tank via the switching valve. In addition, when the switching valve is switched from the normal position to the switching position, the return fluid of the actuator to which the inertia energy or the position energy is applied is guided to the fluid pressure motor. And since the generator is connected with this fluid pressure motor, if a fluid pressure motor rotates with the above-mentioned return fluid, a generator will rotate and it will generate electric power with the torque. The return fluid from the fluid pressure motor is returned to the tank as it is. That is, the return fluid from the actuator is returned to the tank via the fluid pressure motor connected to the generator.
JP 2004-11168 A

  In the conventional apparatus as described above, for example, when the battery connected to the generator is fully charged, the rotational resistance of the generator is naturally reduced. Therefore, the load of the fluid pressure motor connected to the generator is also reduced, but if the rotational load of the fluid pressure motor is reduced in this way, the number of rotations also increases. If the rotation speed of the fluid pressure motor increases, the flow rate per unit time returned from the actuator to the tank via the fluid pressure motor increases. If the return flow rate per unit time increases, the operating speed of the actuator will be higher than the speed intended by the operator. In other words, the conventional device has a problem that the operating speed of the actuator varies depending on the state of charge of the battery.

Also, for some reason, troubles occur in the fluid pressure motor and generator, and when the smooth rotation of the fluid pressure motor is impaired, the actuator operating speed increases for the same reason as above. There was a problem. In addition, even when trouble occurs in the fluid pressure motor or generator as described above and power generation becomes impossible, the return fluid from the actuator continues to be supplied to the fluid pressure motor, so the energy loss is reduced. There was a problem of getting bigger.
The object of the present invention is to provide an energy conversion in which the operating speed of the actuator does not change and the workability is not deteriorated even when the battery is fully charged or when trouble occurs in the hydraulic motor or generator. Is to provide a device.

The present invention relates to a pump, a closed center type first pilot switching control valve connected to the pump, an actuator communicating with the first pilot switching control valve via first and second passages, and an operation direction of an operation lever. And a pilot control mechanism that guides the pilot pressure to one of the pilot chambers provided at both ends of the first pilot switching control valve and controls the pilot pressure according to the operation amount of the operation lever; A motor, a generator connected to the fluid pressure motor, a power generation mechanism including a battery electrically connected to the generator, and a communication process between the second passage and the fluid pressure motor; An energy conversion device including a pilot proportional switching valve whose opening degree is controlled by action is assumed.

In the first aspect of the invention, the actuator is connected in parallel with the first pilot switching control valve, while being kept closed at the neutral position, the actuator is switched by the pilot pressure from the pilot control mechanism, and the switching is performed. When in position, a pump connected to the first pilot switching control valve or a pump different from this pump communicates with the first passage, and a second pilot communicates the second passage with the tank via a throttle. A switching control valve, and a first pilot solenoid valve that selectively guides pilot pressure from the pilot control mechanism to one of the pilot chamber of the first pilot switching control valve or the pilot chamber of the second pilot switching control valve; , A pilot pressure control solenoid valve for controlling the pilot pressure guided to the pilot chamber of the pilot proportional switching valve And a controller for controlling the first pilot solenoid valve and the pilot pressure control solenoid valve. The controller includes the pilot control mechanism, a storage sensor for detecting a storage state of the battery, the fluid pressure motor, and a power generator. This controller is connected to at least one of the fail-safe sensors that detect the operating status of the machine. This controller is based on the operating direction of the pilot control mechanism, the full charge signal from the power storage sensor or the fail signal from the fail-safe sensor. The first pilot solenoid valve and the pilot pressure control so that the second pilot switching control valve is kept closed, the first pilot switching control valve is kept in the switching position, and the pilot proportional switching valve is kept in the closed position. It is characterized in that it is configured to control the solenoid valve.

  According to a second aspect of the present invention, the controller has a function of detecting an operation direction and an operation amount of the pilot control mechanism, and a full charge signal from the power storage sensor or a fail signal from the failsafe sensor is input to the controller. When the pilot control mechanism detects that the pilot pressure for communicating the first passage with the pump is not output, the first pilot solenoid valve is proportional to the operation amount of the pilot control mechanism. The pilot pressure control solenoid valve is operated to control the pilot pressure led to the pilot chamber of the second pilot switching control valve and the pilot pressure led to the pilot chamber of the pilot proportional switching valve, and the throttle of the second pilot switching control valve Controls the opening and the opening of the pilot proportional switching valve, and determines the operation amount of the pilot control mechanism. All return flow Qt, flow rate Qa, which is returned to the tank through the aperture of the second pilot switching control valve, the flow rate Qb supplied to the power generation mechanism that has a feature in that to keep the relation of Qt = Qa + Qb.

  In a third aspect of the invention, the actuator comprises a cylinder having a rod side chamber and a piston side chamber, the first passage is connected to the rod side chamber, and the second passage is connected to the piston side chamber. The valve comprises a closed center type control valve having first and second pilot chambers. Further, the first pump and the second pump are connected to the first and second pilot switching control valves, and the second When the pilot pressure is introduced to the first pilot chamber of the pilot switching control valve, the first passage and the second pump connected to the second pilot switching control valve are communicated, and the second passage and the tank are communicated. On the other hand, when pilot pressure is introduced to the second pilot chamber of the second pilot switching control valve, the second pump is connected to the second passage, and the second pilot switching is performed. The second pilot chamber of the control valve is connected to the pilot control mechanism via the second pilot solenoid valve, and the controller switches the first pilot switching control valve when the acceleration signal to the cylinder is input, One pump is communicated with the second passage, and the first passage is communicated with the tank, while the second pilot solenoid valve is controlled to lead the pilot pressure of the pilot control mechanism to the second pilot chamber. .

  According to the first to third inventions, when a full charge signal from the power storage sensor or a fail signal from the fail-safe sensor is input, the controller controls the first, second pilot switching control valve, and pilot proportional switching valve. Since the actuator is controlled by controlling the actuator, the operation speed of the actuator is not affected even when full charge is reached or a failure occurs.

Further, when a full charge signal or a fail signal is input to the controller, the return fluid from the second passage is prevented from being supplied to the power generation mechanism, and the return fluid is returned from the second pilot switching control valve. Also block. Then, the entire amount of return fluid from the second passage is returned to the tank while being metered out by the first pilot switching control valve. In other words, when a full charge signal or a fail signal is input to the controller, the normal control by only the first pilot switching control valve is automatically returned.
For this reason, even when a full charge state occurs or a failure or the like occurs in the power generation mechanism, the operator can operate based on a normal operational feeling, and the operational feeling does not go wrong.

  Further, according to the second aspect of the invention, the total flow rate of the flow rate Qa returning to the tank via the second pilot switching control valve and the flow rate Qb guided to the power generation mechanism via the pilot proportional switching valve is Since it is proportional to the amount of operation, the operator's feeling of operation does not go wrong even when the power generation mechanism is operating. In other words, since the relative relationship between the operation amount of the pilot control mechanism and the operating speed of the actuator is always constant, the operator's feeling of operation does not go wrong.

  According to the third aspect of the invention, when the acceleration signal for the cylinder is input to the controller, the discharge oil discharged from the first and second pumps is supplied to the cylinder, so that the actuator is controlled at two speeds. be able to.

An embodiment of the present invention will be described with reference to FIG.
As shown in FIG. 1, a closed center type first pilot switching control valve 2 which is a 3-position 4-port valve and is composed of a pilot valve is connected to a cylinder 1 which is an actuator of the present invention. The first pilot switching control valve 2 has its pump port 2a connected to the first pump P1, and the tank port 2b connected to the tank T. In addition, one actuator port 2c of the pair of actuator ports 2c and 2d is connected to the rod side chamber 1a which is one chamber of the cylinder 1 via the first passage 3, and the other actuator port 2d is connected to the second actuator port 2d. The other side chamber is connected to the piston side chamber 1b through the passage 4.

  The first pilot switching control valve 2 configured as described above is provided with springs at both ends thereof, and in the neutral state, all the ports 2a to 2d are kept closed as illustrated. When the pilot pressure is introduced into the first pilot chamber 5 of the first pilot switching control valve 2 and the first pilot switching control valve 2 is switched to the left position in the drawing, the pump port 2a and the actuator port 2d communicate with each other. The port 2b and the actuator port 2c communicate with each other. When the pilot pressure is introduced into the second pilot chamber 6 of the first pilot switching control valve 2 and the first pilot switching control valve 2 is switched to the right side position in the drawing, the pump port 2a and the actuator port 2c are in communication with each other. The tank port 2b and the actuator port 2d communicate with each other. In this way, by guiding the pilot pressure to the first and second pilot chambers 5 and 6 of the first pilot switching control valve 2, the discharge oil discharged from the first pump P1 is guided to the first passage 3 side, It can lead to the 2nd channel | path 4 side.

  The pilot control mechanism 7 controls the first pilot switching control valve 2. The pilot control mechanism 7 applies a pilot pressure to one of the first and second pilot chambers 5 and 6 of the first pilot switching control valve 2 by operating an operation lever 7a constituting the pilot control mechanism 7. The first pilot switching control valve 2 is switched by the pilot pressure, the details of which will be described later. Note that the controller C is electrically connected to the pilot control mechanism 7, and the operation status of the pilot control mechanism 7 is transmitted to the controller C as an electrical signal. The operation state of the pilot control mechanism 7 is, for example, the operation direction and the operation amount of the operation lever 7a.

Further, the cylinder 1 in this embodiment is installed with the piston side chamber 1b facing down. Therefore, when the piston-side chamber 1b is communicated with the tank T and the cylinder 1 is contracted, inertial energy and potential energy act on the cylinder 1 due to the load acting on the cylinder 1. At this time, the first passage 3 is a side for supplying pressure oil to the actuator, and the second passage 4 is a side for guiding return fluid from the actuator.
As a matter of course, when the piston side chamber 1b is communicated with the pump, the cylinder 1 increases the load acting on the cylinder 1, so that the inertial energy due to the load acting on the cylinder 1 is negligibly small. . Therefore, in the present invention, when inertial energy or potential energy acts on the actuator, it means only when the cylinder 1 is contracted.

  As described above, when the cylinder 1 contracts, inertial energy and potential energy according to the load act. As described above, when energy acts on the cylinder 1, the return fluid from the actuator is supplied. A connection passage 8 is connected to the second passage 4 on the guiding side. In addition, a connection passage 9 is connected to the first passage 3 on the side where pressure oil is supplied to the actuator when energy acts on the cylinder 1.

In the connection passages 8 and 9, a second pilot switching control valve 10 having the following configuration is connected in parallel to the actuator.
That is, the second pilot switching control valve 10 is a three-position four-port valve and is a closed center type pilot valve, like the first pilot switching control valve 2. The second pilot switching control valve 10 has its pump port 10a connected to the second pump P2, and the tank port 10b connected to the tank T. Also, of the pair of actuator ports 10c and 10d, one actuator port 10c is connected to the piston side chamber 1b of the cylinder 1 via the connection passage 8 and the second passage 4, and the other actuator port 10d is connected to the connection passage 9 The first passage 3 is connected to the rod-side chamber 1a.

  The above-described second pilot switching control valve 10 is provided with springs at both ends thereof, and keeps all the ports 10a to 10d closed in the neutral state as shown in the figure. When the pilot pressure is introduced into the first pilot chamber 11 of the second pilot switching control valve 10 and the second pilot switching control valve 10 is switched to the switching position on the left side of the drawing, the pump port 10a and the actuator port 10d communicate with each other. The tank port 10b and the actuator port 10c communicate with each other. However, a throttle is formed in the communication process between the actuator port 10c and the tank port 10b, and the connection passage 8 and the tank T communicate with each other through this throttle.

When the pilot pressure is introduced into the second pilot chamber 12 of the second pilot switching control valve 10 and the second pilot switching control valve 10 is switched to the right position in the drawing, the pump port 10a and the actuator port 10c communicate with each other, and the tank The port 10b and the actuator port 10d are blocked. Therefore, when the second pilot switching control valve 10 is switched to the right side position in the drawing, the discharged oil discharged from the second pump P2 is guided to the piston side chamber 1b through the connection passage 8 and the second passage 4. However, at this time, the return fluid from the rod side chamber 1 a is not guided to the tank T via the second pilot switching control valve 10.
The neutral position of the second pilot switching control valve 10, that is, the position where the oil discharged from the second pump P2 is not supplied to any of the first and second passages 3 and 4 is referred to as the closed position, and the second pilot switching control valve. The position at which 10 is switched from the closed position to the left or right and the discharge oil of the second pump P2 is supplied to one of the first and second passages 3 and 4 is referred to as a switching position.

  The pilot pressure of the second pilot switching control valve 10 is controlled by the pilot control mechanism 7. The pilot pressure is guided from the pilot control mechanism 7 to the first and second pilot chambers 11 and 12. The pilot line is provided with a first pilot solenoid valve 13 and a second pilot solenoid valve 14 each comprising a 2-position 4-port valve. The first and second pilot solenoid valves 13 and 14 are connected to the controller C and controlled by the controller C.

The first pilot solenoid valve 13 applies the pilot pressure from the pilot control mechanism 7 to one of the second pilot chamber 6 of the first pilot switching control valve 2 and the first pilot chamber 11 of the second pilot switching control valve 10. Selective guidance. That is, when the first pilot solenoid valve 13 is maintained at the illustrated position, the pilot pressure is guided to the pilot chamber 11 of the second pilot switching control valve 10 and the pilot chamber 6 of the first pilot switching control valve 2 is opened. Communicate with the tank T.
When the controller C transmits a signal to switch the first pilot solenoid valve 13 to the left position in the drawing, the pilot pressure is guided to the pilot chamber 6 of the first pilot switching control valve 2 and the second pilot switching control valve 10. The pilot chamber 11 is communicated with the tank T.

The second pilot solenoid valve 14 controls the pilot pressure led to the second pilot chamber 12 of the second pilot switching control valve 10. That is, when the second pilot solenoid valve 14 is in the illustrated position, pilot pressure is guided from the pilot control mechanism 7 to the second pilot chamber 12. Then, when the controller C controls the second pilot solenoid valve 14 and the second pilot solenoid valve 14 is switched from the illustrated position to the right side position in the drawing, the pilot chamber 12 of the second pilot switching control valve 10 is set to the tank T. Communicate.
As described above, the controller C controls the first and second pilot solenoid valves 13 and 14 and the pilot pressure led to the pilot chambers 6, 11, and 12. This is performed in conjunction with the operation amount of 7a and various signals described later.

  The connection passage 8 is connected to a pilot proportional switching valve S which is a 2-position 4-port valve. The pilot proportional switching valve S includes supply ports 15a and 15b and return ports 16a and 16b. One supply port 15 a is connected to the second passage 4 via the connection passage 8, and the other supply port 15 b is connected to the supply flow path 17 on the supply side with respect to the fluid pressure motor M. Yes. The fluid pressure motor M is a power source for the generator G. The generator G generates power as the fluid pressure motor M rotates, and the power generated by the generator G is stored in the battery V. These fluid pressure motor M, generator G and battery V constitute the power generation mechanism of the present invention.

  The one return port 16a is connected to the tank T via the passage 18, and the other return port 16b is connected to the return flow path 19 on the return side with respect to the fluid pressure motor M. . The pilot proportional switching valve S thus configured has a spring 20 on one side and a pilot chamber 21 on the other side. The pilot pressure guided to the pilot chamber 21 is controlled by a pilot pressure control electromagnetic valve 22 connected to the controller C. That is, the controller C controls the excitation current led to the solenoid 22a of the pilot pressure control solenoid valve 22, thereby leading the pilot pressure corresponding to the excitation current to the pilot chamber 21 and proportional to the pilot pressure according to the pilot pressure. The switching valve S is switched.

  The pilot proportional switching valve S configured as described above maintains the illustrated closed position by the action of the spring 20 when the pilot pressure is not acting on the pilot chamber 21. In this closed position, the supply ports 15a and 15b are closed, and the return ports 16a and 16b are maintained in a state where the throttle opening is maintained. When the pilot pressure is introduced into the pilot chamber 21 as described above and the pilot proportional switching valve S is switched from the closed position to the open position, the supply ports 15a and 15b and the return ports 16a and 16b are opened. The opening at that time is controlled according to the exciting current of the solenoid 22a as described above. However, the excitation current of the solenoid 22a is controlled by the controller C, and is controlled so as to interlock with the operation lever 7a of the pilot control mechanism 7 and the pilot pressure control mechanism.

  In any case, when the pilot proportional switching valve S is in the closed position shown in the figure, the return fluid from the piston side chamber 1b is not guided to the supply flow path 17, so that the fluid pressure motor M does not rotate. The generator G does not function as well. From this state, when the pilot proportional switching valve S is switched to the open position, the return fluid is guided to the supply flow path 17 and the return flow path 19 communicates with the tank T. Therefore, the fluid pressure motor M rotates and generates power. The machine G is rotated to generate electric power, and the electric power generated in this way is stored in the battery V.

  In addition, a short-circuit channel 23 for short-circuiting both the supply channel 17 and the return channel 19 is provided between the supply channel 17 and the return channel 19, and the short-circuit channel 23 is connected to the supply channel 17 from the return channel 19. A check valve 24 that allows only flow is provided. Further, a relief valve 25 is provided in parallel with the check valve 24 so as to control the maximum pressure on the supply flow path 17 side. Note that by making the set pressure of the relief valve 25 variable, the device can be adapted to various generators having different allowable torques. Furthermore, a replenishment flow path 26 is connected to the supply flow path 17 so that the shortage of the flow rate on the supply flow path 17 side is compensated from the tank T. Reference numeral 27 in the figure is a check valve provided in the replenishment flow path 26 and allows only the flow from the tank T to the supply flow path 17.

  The controller C is connected with a power storage sensor 28 for detecting the power storage status of the battery V, and with a fail safe sensor 29 for detecting the operating status of the power generation mechanism including the fluid pressure motor M and the generator G. Has been. This fail-safe sensor 29 detects a failure and sends a fail signal notifying the controller C of the failure when the power generation mechanism fails and does not function normally.

  Then, the controller C combines the first pilot solenoid valve 13 from the power storage status of the battery V transmitted from the power storage sensor 28, the fail signal transmitted from the failsafe sensor 29, and the operating status of the pilot control mechanism 7. The second pilot solenoid valve 14 and the pilot pressure control solenoid valve 22 are controlled. The control performed by the controller C will be described in detail in the following description of the operation.

The operation of this embodiment will be described below.
When the operator operates the operation lever 7a so as to increase the load acting on the cylinder 1, the pilot control mechanism 7 guides the pilot pressure only to the first pilot chamber 5 of the first pilot switching control valve 2, and the controller C On the other hand, an operation signal for communicating the second passage 4 with the pump is output. The controller C that detects the signal of the pilot control mechanism 7 controls the first pilot solenoid valve 13 and the second pilot solenoid valve 14 so as to maintain the position from the illustrated position to the right side of the drawing, and the pilot proportional switching valve S is controlled. The pilot pressure control electromagnetic valve 22 is controlled so as to maintain the illustrated closed position.

  As described above, since the first pilot solenoid valve 13 is maintained at the illustrated position, the second pilot chamber 6 of the first pilot switching control valve 2 communicates with the tank T, and the first pilot switching control valve 2 is shown in the drawing. Switching to the left side position causes the discharged oil of the first pump P1 to be guided to the piston side chamber 1b of the cylinder 1 through the second passage 4.

At this time, since the pilot control mechanism 7 does not guide the pilot pressure to the first pilot chamber 11 and the second pilot chamber 12 of the second pilot switching control valve 10, the second pilot switching control valve 10 is connected to both ends thereof. The neutral position is maintained by the provided spring, and the second pump P2 and the tank T are disconnected from the connection passages 8 and 9.
Therefore, only the discharge oil from the first pump P1 is guided to the piston side chamber 1b via the first pilot switching control valve 2. Further, since the power generation mechanism and the connection passage 8 are blocked by the pilot proportional switching valve S, the return fluid from the rod side chamber 1a is guided to the tank T only through the first pilot switching control valve 2. .
When the controller C detects an operation signal for controlling the pilot pressure for communicating the second passage 4 with the first pump P1 in the pilot control mechanism 7, the signals of the power storage sensor 28 and the fail safe sensor 29 are detected. Regardless of the above control.

When the operator operates the operation lever 7a from the above state so as to increase the speed at which the load acting on the cylinder 1 is increased, the pilot control mechanism 7 causes the second pilot switching control valve 10 to operate as the second pilot. A pilot pressure is also introduced into the chamber 12 and an acceleration signal is output to the controller C. The controller C to which the speed increasing signal is input controls to keep the second pilot solenoid valve 14 at the illustrated position. Therefore, the second pilot switching control valve 10 is switched to the right side position in the drawing, and the discharged oil from the second pump P2 is guided to the second passage 4 via the second pilot switching control valve 10 and the connection passage 8.
Thus, when the acceleration signal is input to the controller C, the discharged oil from the first pump P1 is guided to the piston side chamber 1b via the first pilot switching control valve 2, and the discharged oil from the second pump P2. However, since it is led to the piston side chamber 1b via the second pilot switching control valve 10, the speed of increasing the load acting on the cylinder 1 can be increased. However, the return fluid from the rod side chamber 1a is guided to the tank T only through the first pilot switching control valve 2.

  As described above, when the operator performs so-called first speed control, the discharge oil of the first pump P1 is guided only from the first pilot switching control valve 2 side, and when so-called second speed control is performed, the first pilot switching is performed. Since the discharge oil of the second pump P2 guided from the second pilot switching control valve 10 side joins the discharge oil of the first pump P1 guided from the control valve 2 side and is guided to the piston side chamber 1b, the operating speed of the cylinder 1 Can be controlled in two stages.

Even when the second speed control is performed, the controller C detects the operation signal for controlling the pilot pressure for communicating the second passage 4 with the pump in the pilot control mechanism 7. As in the case of the first speed control, the second speed control is performed regardless of the signals from the power storage sensor 28 and the fail safe sensor 29.
In this embodiment, the case of switching from the state in which the first speed control is performed to the second speed control has been described. However, the second speed control is suddenly performed on the operation lever 7a from the state in which the operation lever 7a is not operated. Even when an operation to be performed is performed, the controller C performs the same control as described above.

On the other hand, when the operator operates the operation lever 7 a so as to lower the load acting on the cylinder 1, the pilot control mechanism 7 guides the pilot pressure only to the pilot line communicating with the second pilot chamber 6 and the first pilot chamber 11. At the same time, an operation signal for communicating the first passage 3 with the pump P is output to the controller C.
When the controller C detects the output signal of the pilot control mechanism 7, it determines whether a full charge signal from the power storage sensor 28 or a fail signal from the fail safe sensor 29 is input, and the full charge signal and When no fail signal is input, the following control is performed.

That is, the controller C controls the first pilot solenoid valve 13 to be kept at the illustrated position, controls the second pilot solenoid valve 14 to be switched from the illustrated position to the right side position in the drawing, and the pilot proportional switching valve S. The pilot pressure control solenoid valve 22 is controlled so as to switch from the closed position shown in the figure to the open position.
As described above, the first pilot solenoid valve 13 is maintained at the illustrated position, so that the second pilot chamber 6 of the first pilot switching control valve 2 communicates with the tank T, and the first pilot switching control valve 2 has both ends thereof. The first pump P1 and the tank T and the first and second passages 3 and 4 are shut off by being kept in the neutral position by the spring provided in the first position.

At this time, since the pilot control mechanism 7 is led to the pilot pressure to the pilot line communicating with the first pilot chamber 11, the pilot pressure is in the second pilot changeover valve 10 via a first pilot solenoid valve 13 Guided to the pilot room 11. Moreover, since the second pilot solenoid valve 14 is switched to the right side position in the drawing, the second pilot chamber 12 communicates with the tank T, and the second pilot switching control valve 10 is switched to the left side position in the drawing.
Accordingly, the discharge oil from the second pump P2 is guided to the rod side chamber 1a of the cylinder 1 through the second pilot switching control valve 10, the connection passage 9, and the first passage 3, and the connection passage 8 and the tank T are connected to each other. It will communicate through a diaphragm.

However, at this time, since the pilot proportional switching valve S is switched to the open position as described above, the piston side chamber 1b communicates with the power generation mechanism, and the return fluid from the piston side chamber 1b is supplied to the second pilot switching control valve 10. The remaining fluid is led from the connection passage 8 to the supply passage 17, and the fluid pressure motor M rotates at the pressure to turn the generator G to exhibit the power generation function.
As described above, when the load acting on the cylinder 1 is lowered, the inertial energy or potential energy of the cylinder 1 can be converted into electric energy by the load acting on the cylinder 1.

The controller C controls the first pilot solenoid valve 13 and the pilot pressure control solenoid valve 22 in proportion to the operation amount of the operation lever 7a, and the throttle opening degree of the second pilot switching control valve 10 and the pilot proportional switching valve. If the opening degree of S is controlled as follows, the operator's feeling of operation will not be confused more.
That is, the controller C sets the total return flow rate determined by the operation amount of the operation lever 7a as Qt, the flow rate returned to the tank T through the throttle of the second pilot switching control valve 10 as Qa, and the flow rate supplied to the power generation mechanism. When Qb is set, control is performed so as to maintain a relationship of Qt = Qa + Qb.

  Thus, the total flow rate of the flow rate Qa returning to the tank via the second pilot switching control valve 10 and the flow rate Qb guided to the power generation mechanism via the pilot proportional switching valve S is determined by the operation amount of the operation lever 7a. If the control is made so that it is always equal to the total return flow rate Qt, the operator's feeling of operation does not go wrong even when the power generation mechanism is operated. In other words, the relative relationship between the operation amount of the pilot control mechanism 7 and the operating speed of the actuator is always constant even when a full charge situation occurs or a failure occurs in the power generation mechanism. The feeling of operation does not go crazy.

When the power generation function is operated as described above, as a result of the electric energy generated by the generator G being charged in the battery V, a full charge signal is input from the power storage sensor 28 or a fail-safe sensor. When a fail signal is input from 29, the controller C performs the following control.
That is, the controller C to which the full charge signal or the fail signal is input switches the first pilot solenoid valve 13 to the left position in the drawing and the pilot pressure control solenoid valve 22 so as to switch the pilot proportional switching valve S to the closed position shown in the figure. To control.
Therefore, the pilot pressure led from the pilot control mechanism 7 to the first pilot chamber 11 of the second pilot switching control valve 10 is led to the second pilot chamber 6 of the first pilot switching control valve 2. Further, since the pilot chamber 11 of the second pilot switching control valve 10 communicates with the tank T, the second pilot switching control valve 10 is maintained in the closed position, which is the neutral position, by the springs provided at both ends thereof. P2 and the tank T and the connection passages 8 and 9 are blocked.

On the other hand, the first pilot switching control valve 2 to which the pilot pressure is guided to the second pilot chamber 6 is switched to the right side position in the drawing by the pilot pressure. Accordingly, the first pump P1 and the first passage 3 communicate with each other, the tank T and the second passage 4 communicate with each other, and the discharge oil of the first pump P1 is guided to the rod side chamber 1a of the cylinder 1.
In addition, at this time, the pilot pressure led to the first pilot chamber 11 of the second pilot switching control valve 10 is led to the second pilot chamber 6 as it is under the control of the first pilot electromagnetic valve 13.
Further, as described above, the controller C controls the pilot pressure control electromagnetic valve 22 to switch the pilot proportional switching valve S to the closed position, so that the piston side chamber 1b and the power generation mechanism are shut off and the power generation function is stopped. At the same time, all of the return fluid from the piston side chamber 1b is returned to the tank T via the first pilot switching control valve 2.
In addition, the total flow rate Qt that has been returned to the tank T via the power generation mechanism and the throttle of the second pilot switching control valve 10 is equal to the flow rate that is returned to the tank T via the first pilot switching control valve 2. In addition, if the controller C controls the first pilot solenoid valve 13, even if the power generation function is suddenly stopped, the operator's feeling of operation can be prevented from being upset.

Thus, when an abnormality occurs in the fully charged state or the power generation mechanism, the controller C controls the power generation mechanism not to operate, so that the battery V can be prevented from becoming an applied voltage.
In the above embodiment, the case where a full charge signal or a fail signal is input while the power generation mechanism is operating has been described. However, the operator operates the operation lever 7a so as to lower the load acting on the cylinder 1. When the controller C determines that a full charge signal or a fail signal is input, the controller C performs the same control as described above.

  According to the above embodiment, when a full charge signal from the power storage sensor 28 or a fail signal from the fail safe sensor 29 is input, the controller C controls the first and second pilot switching control valves 2 and 10 and the pilot proportionality. Since the switching valve S is controlled to control the actuator, the operating speed of the actuator is not affected even when full charge is reached or a failure occurs.

When a full charge signal or a fail signal is input to the controller C, the return fluid from the second passage 4 is prevented from being supplied to the power generation mechanism, and the return fluid is supplied from the second pilot switching control valve 10. It also prevents it from being returned. Then, the entire amount of the return fluid from the second passage 4 is returned to the tank T while being metered out by the first pilot switching control valve 2. In other words, when a full charge signal or a fail signal is input to the controller C, the normal control by only the first pilot switching control valve 2 is automatically returned.
For this reason, even when a full charge state occurs or a failure or the like occurs in the power generation mechanism, the operator can operate based on a normal operational feeling, and the operational feeling does not go wrong.
Moreover, when an acceleration signal for the cylinder 1 is input, the discharged oil is supplied to the cylinder 1 from the two pumps, the first and second pumps P1 and P2, so that the actuator can be controlled at two speeds. .

  If the pilot proportional switching valve S is switched to the closed position, the supply of the return fluid to the fluid pressure motor M is cut off, so that the fluid pressure motor M tries to stop, but the fluid pressure motor M and the power generation The inertia energy of the machine G keeps rotating until the energy is absorbed. When the fluid pressure motor M continues to rotate with inertial energy in this way, the fluid pressure motor M substantially performs a pumping action. Accordingly, the hydraulic oil is sucked in from the supply flow path 17 side and is discharged to the return flow path 19 side. However, since the supply ports 15a and 15b of the pilot proportional switching valve S are closed as described above, the fluid pressure The motor M cannot sufficiently suck hydraulic oil from the supply flow path 17.

  However, at this time, the hydraulic oil discharged from the fluid pressure motor M to the return flow path 19 side is returned to the supply flow path 17 side where the pressure is low via the short-circuit path 23. Moreover, since the hydraulic oil in the tank T is also supplied from the supply flow path 26, the problem that negative pressure is generated on the suction side of the fluid pressure motor M and cavitation occurs is solved.

In addition, for example, the operation of extending or contracting the cylinder 1 may be repeated in a short time. If such an operation is repeated in a short time, the pilot proportional switching valve S also substantially turns on and off. Will repeat. However, the fluid pressure motor M connected to the generator G having a large inertial energy generally cannot be repeatedly stopped and driven in a short time, but in this embodiment, the pilot proportional switching valve S is operated in a short time. Even if ON / OFF is repeated, the fluid pressure motor M can absorb the inertia energy of the generator G while continuing to rotate with inertia, and no negative pressure is generated on the supply flow path 17 side. Does not occur.
Moreover, even if the pilot proportional switching valve S is suddenly switched to the closed position, the return ports 16a and 16b maintain the throttle opening so that no shock is generated in the fluid pressure motor M.

  In the above embodiment, the two pumps, the first pump P1 and the second pump P2, are used. If the second speed control is ignored, one pump is used and The first and second pilot switching control valves 2 and 10 may be connected in parallel.

It is a circuit diagram of this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cylinder which is an actuator 1a Rod side chamber 1b Piston side chamber 2 1st pilot switching control valve 3 1st passage 4 2nd passage 5 1st pilot chamber 6 2nd pilot chamber 7 Pilot control mechanism 7a Operation lever 10 2nd pilot switching control valve DESCRIPTION OF SYMBOLS 11 1st pilot chamber 12 2nd pilot chamber 13 1st pilot solenoid valve 14 2nd pilot solenoid valve 21 Pilot chamber 22 Pilot pressure control solenoid valve 28 Accumulation sensor 29 Fail safe sensor C Controller G Generator M Fluid pressure motor P1 1st Pump P2 Second pump S Pilot proportional switching valve T Tank V Battery

Claims (3)

A pump, a first pilot switching control valve of closed center type connected to the pump, an actuator in communication through the first pilot switching valve and the first and second passage, depending on the operating direction of the control lever, A pilot control mechanism that guides the pilot pressure to one of the pilot chambers provided at both ends of the first pilot switching control valve and controls the pilot pressure according to the operation amount of the operation lever, a fluid pressure motor, and the fluid A generator connected to the pressure motor and a power generation mechanism including a battery electrically connected to the generator, and the second passage and the fluid pressure motor are connected to each other, and the opening degree is obtained by the pilot pressure in the pilot chamber. in the energy conversion device but having a pilot proportional control valve is controlled, the first pyrotechnic relative to the actuator While connected to preparative switching control valve and parallel, maintaining the closed state in the neutral position, switched by the pilot pressure from the pilot control mechanism, and, when in this switching position, the pump connected to the first pilot switching control valve Alternatively, a second pilot switching control valve for communicating a pump different from this pump and the first passage, and a second passage and a tank for communication via a throttle, and one pilot chamber of the first pilot switching control valve Alternatively, the first pilot solenoid valve that selectively guides the pilot pressure from the pilot control mechanism to one of the pilot chambers of the second pilot switching control valve and the pilot pressure that is guided to the pilot chamber of the pilot proportional switching valve are controlled. A pilot pressure control solenoid valve for controlling the first pilot solenoid valve and the pilot pressure control solenoid valve A controller, and the controller is connected to at least one of the pilot control mechanism and a storage sensor for detecting the storage state of the battery or a fail-safe sensor for detecting the operation state of the fluid pressure motor or generator. Thus, the controller keeps the second pilot switching control valve in a closed state based on the operation direction of the pilot control mechanism, the full charge signal from the power storage sensor or the fail signal from the fail-safe sensor , An energy conversion device configured to control the first pilot solenoid valve and the pilot pressure control solenoid valve so as to keep the pilot switching control valve at a switching position and keep the pilot proportional switching valve at a closed position .
  The controller has a function of detecting the operation direction and the operation amount of the pilot control mechanism, in a state where neither a full charge signal from the power storage sensor nor a fail signal from the fail safe sensor is input to the controller, When detecting that the pilot control mechanism outputs a pilot pressure for communicating the first passage with the pump, the first pilot solenoid valve and the pilot pressure control solenoid valve are proportional to the operation amount of the pilot control mechanism; And the pilot pressure led to the pilot chamber of the second pilot switching control valve and the pilot pressure led to the pilot chamber of the pilot proportional switching valve are controlled, and the throttle opening of the second pilot switching control valve and the pilot proportional The total return flow rate determined by the amount of operation of the pilot control mechanism. t, the flow rate Qa, which is returned to the tank through the aperture of the second pilot switching control valve, the flow rate Qb, which is supplied to the power generation mechanism, the energy conversion device according to claim 1, wherein a configuration to maintain the relation of Qt = Qa + Qb.   The actuator is composed of a cylinder having a rod side chamber and a piston side chamber, and the first passage is connected to the rod side chamber and the second passage is connected to the piston side chamber. The control valve comprises a closed center type control valve having a second pilot chamber. Further, the first pump and the second pump are connected to the first and second pilot switching control valves. When pilot pressure is introduced into one pilot chamber, the first passage communicates with the second pump connected to the second pilot switching control valve, and the second passage communicates with the tank while the second pilot switching. When pilot pressure is introduced into the second pilot chamber of the control valve, the second pump is connected to the second passage, and the second pilot switching control valve The lot chamber is connected to the pilot control mechanism via the second pilot solenoid valve, and the controller switches the first pilot switching control valve when the acceleration signal to the cylinder is input, and the first pump is switched to the second pump. 3. The structure according to claim 1, wherein the first passage is communicated with the tank, the first passage is communicated with the tank, and the second pilot solenoid valve is controlled to guide the pilot pressure of the pilot control mechanism to the second pilot chamber. Energy conversion device.

Images