JP4703361B2 - Energy converter - Google Patents

Description

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

As this type of apparatus, an apparatus described in Patent Document 1 has been conventionally known. This conventional device is provided with a switching valve that switches on and off in a return passage when inertial energy or potential energy acts on the actuator. When the switching valve is in the normal position, the return oil of the actuator to which inertia energy or potential energy has acted returns to the tank via the switching valve. Further, when the switching valve is switched from the normal position to the switching position, the return oil of the actuator to which the inertia energy or the position energy is applied is guided to the hydraulic motor. Since a generator is connected to the hydraulic motor, if the hydraulic motor rotates with the return oil, the generator rotates with the rotational force to generate electric power.
JP 2004-11168 A

  In the conventional apparatus as described above, when the switching valve is switched from the switching position to the normal position, in other words, the switching valve is held in the switching position and the hydraulic motor is being driven. When the actuator is suddenly returned to the normal position and the actuator is returned to the normal control, negative pressure is generated on the hydraulic motor side connected to the generator. This is because even if the switching valve is switched to the normal position, the inertial energy of the hydraulic motor and the generator is large, so that they do not stop immediately. In particular, since the inertial energy of the generator is large, the hydraulic motor connected to the generator cannot be stopped suddenly, and negative pressure is generated on the suction side.

  When the suction side of the hydraulic motor becomes negative as described above, cavitation occurs there, but this cavitation causes noise and damages the sliding part of the hydraulic motor. Therefore, in order to prevent the negative pressure from being generated, for example, the switching control valve for controlling the actuator may be switched slowly, but this makes it impossible to control the actuator crisply. In any case, the conventional apparatus has a problem that cavitation is likely to occur, and if it is attempted to cover the problem with the operation capability of the operator, there is a problem that crisp control cannot be performed this time.

  Further, even if the switching valve is switched to the normal position in order to stop the hydraulic motor and the generator, the inertia energy of the generator is very large as described above, so that it does not stop easily. If it takes too much time for the hydraulic motor or generator to stop, the negative pressure on the suction side of the hydraulic motor will further increase. Therefore, when the switching valve is switched to the normal position, the hydraulic motor and the generator must be stopped quickly, but if the energy is to be absorbed in a short time, the generator must be enlarged. This is because, in order to absorb the inertial energy, the generator must absorb the energy in the form of electrical conversion. Therefore, if the energy absorption time is to be shortened, the generator must be enlarged. Because there is no. However, if the generator is increased in size, the inertial energy of the generator will increase more and more, and absorbing the inertial energy in a short time and keeping the generator small is a trade-off. The conventional apparatus cannot solve them all at once.

  Further, when the inertia energy or potential energy acts on the actuator, the return path is connected to the hydraulic motor as described above, and when the actuator is returned directly to the tank without being connected to the hydraulic motor, The operating speed may differ. If the operating speeds of the actuators are different in this way, the operator is impressed as a difference in operational feeling, and there is a problem that the uncomfortable feeling deteriorates operability.

  According to the first aspect of the invention, the return flow from the actuator is guided to the hydraulic motor in accordance with the switching position of the switching valve, and the return flow from the hydraulic motor is returned to the tank via the switching valve, while the hydraulic motor In an energy conversion device for generating power by connecting a generator to the generator and driving the generator with the rotational force of the hydraulic motor, a short-circuit channel is provided between the supply channel and the return channel connecting the switching valve and the hydraulic motor. The short-circuit channel is provided with a check valve that allows only flow from the return channel to the supply channel, and the supply channel is connected to a supply channel for supplying hydraulic oil. Have

  In the second invention, the switching valve is one or a pair of electromagnetic proportional switching valves, and the electromagnetic proportional switching valve closes the supply port communicating with the supply flow path and returns to the return flow path. It is characterized in that the port has one switching position for maintaining the throttle opening and the other switching position for electromagnetically opening the supply port and the return port.

A third invention, the switching control valve for controlling the actuator, the passage comprising a side return when inertial energy and potential energy in the actuator is applied, the opening is changed in accordance with the switching of the switching control valve A throttle is provided, and the passage provided with the throttle is connected to the supply port of the electromagnetic proportional switching valve . The electromagnetic proportional switching valve is switched in synchronization with the switching control valve and is returned from the actuator. Of the flow rate Qc, a flow rate Qm other than the flow rate Qt that passes through the throttle is configured to flow to the hydraulic motor, and the flow rate Qt that flows through the throttle of the switching control valve and flows to the tank passes through the electromagnetic proportional switching valve. total flow rate of the flow rate Qm flowing to the hydraulic motor Te has a feature in that the equal configuration to the flow rate Qc required for the actuator of the return control

  The fourth invention is characterized in that a relief valve is provided between the supply channel and the return channel, and the maximum pressure of the supply channel is set by the relief valve.

  According to the first invention, when the supply port of the switching valve is closed, the hydraulic motor is short-circuited via the short-circuit channel, so that the hydraulic oil discharged by itself can be returned to the suction side. Moreover, since the shortage can be further replenished from the replenishment flow path, even if the hydraulic motor and the generator continue to rotate with inertial energy with the supply port closed, no negative pressure is generated on the suction side of the hydraulic motor. . Therefore, cavitation does not occur as in the prior art, and problems such as noise and hydraulic motor damage caused by this cavitation do not occur.

  Moreover, even if the switching valve is kept in the neutral position as described above, there is no problem even if each of the hydraulic motor and the generator keeps rotating with inertial energy, so a generator having a size suitable for the purpose can be freely set. You can choose. For example, if a large amount of inertial energy is to be absorbed in a short time with a conventional device, a correspondingly large generator must be used. However, since a large generator has a larger inertial energy, there is a limit to the size of the generator that can be adopted. However, according to the present invention, inertial energy can be absorbed regardless of the size of the hydraulic motor and the generator, so that the degree of freedom in design for selecting the size of the generator is greatly increased.

  According to the second invention, since the electromagnetic proportional switching valve whose switching amount is controlled according to the excitation current is used, the amount of oil supplied to the hydraulic motor can be freely controlled as necessary. In addition, when the supply port of the electromagnetic proportional switching valve is closed, the return port can maintain the throttle opening, and no back pressure acts on the hydraulic motor. Therefore, the throttle opening functions as a shockless function for the hydraulic motor when the supply port is closed.

  According to the third invention, the total flow rate of the flow rate Qt that flows through the switching control valve connected to the actuator and flows to the tank and the flow rate Qm that flows through the electromagnetic proportional switching valve and flows to the hydraulic motor is controlled by the control mechanism. Since the flow rate is equal to the flow rate Qc required for the return control of the actuator, the opening degree of the switching control valve and the electromagnetic proportional switching valve is equal to the operation speed of the actuator when it is not necessary to supply the flow rate to the hydraulic motor. Can be controlled. Therefore, even when the generator is driven, the operator can operate the actuator without a sense of incongruity.

  According to the fourth invention, since the maximum pressure of the pressure oil supplied to the hydraulic motor can be controlled, the operation within the allowable torque range of the generator is possible. Further, by making the set pressure of the relief valve variable, the device can be adapted to various generators having different allowable torques.

  In the first embodiment shown in FIG. 1, a switching control valve 2 that is a three-position four-port valve is connected to a cylinder 1 that is an actuator of the present invention. The pump port 2a is connected to a pump P, and a tank Port 2b is connected to tank T. Further, of the pair of actuator ports 2c and 2d, one actuator port 2c is connected to the rod side chamber 1a of the cylinder 1 via the passage 3, and the other actuator port 2d is connected to the piston side chamber 1b via the passage 4. Connected.

  The switching control valve 2 configured as described above maintains all the ports 2a to 2d in a closed state when in the illustrated neutral position. When the switching control valve 2 is switched to the left position in the drawing, the pump port 2a communicates with the actuator port 2d, and the tank port 2b communicates with the actuator port 2c. Accordingly, the oil discharged from the pump P is supplied to the piston side chamber 1b of the cylinder 1 to extend the cylinder 1, and the return oil from the rod side chamber 1a is returned to the tank T. Further, when the switching control valve 2 is switched to the right position in the drawing, the piston side chamber 1b communicates with the tank T and the rod side chamber 1a communicates with the pump P, and the cylinder 1 is contracted.

  In addition, the cylinder 1 in this embodiment is installed in the state which turned down the piston side chamber 1b. 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 by the load acting on the cylinder 1, and at this time, the passage 4 Is the return path. As a matter of course, when the piston side chamber 1b is communicated with the pump P, the cylinder 1 raises the load acting on it, so that inertial energy due to the load does not act on the cylinder 1.

  The pilot control mechanism 5 controls the switching control valve 2 as described above. The pilot control mechanism 5 guides a pilot pressure to one of the pilot chambers of the switching control valve 2 by operating the operating lever 5a, and switches the switching control valve 2 with the pilot pressure as described above. ing.

  As described above, when the cylinder 1 is contracted, inertia energy or potential energy according to the load acts. As described above, the passage 4 on the return side when energy acts on the cylinder 1 as described above. Is connected to an electromagnetic proportional switching valve S which is a two-position four-port valve. The electromagnetic proportional switching valve S has its switching amount controlled in accordance with an electric signal. That is, the electromagnetic proportional switching valve S includes supply ports 6a and 6b and return ports 7a and 7b. One supply port 6a is connected to the passage 4 via the connection passage 8, and the other supply port 6b is a supply flow on the supply side with respect to the hydraulic motor M which is a power source of the generator G. Connected to Road 9.

The one return port 7a is connected to the tank T through the connection passage 10, and the other return port 7b is connected to the return flow path 11 on the return side with respect to the hydraulic motor M. . The electromagnetic proportional switching valve S thus configured has a spring 12 on one side and a pilot chamber 13 on the other side. A pilot pressure control valve 14 is connected to the pilot chamber 13, and this pilot pressure control valve 14 controls the pilot pressure according to the exciting current of the solenoid 14a. Accordingly, the pilot pressure control valve 14 guides the pilot pressure corresponding to the exciting current supplied to the solenoid 14a to the pilot chamber 13, and the electromagnetic proportional switching valve S is switched according to the magnitude of the pilot pressure. become.

  When the pilot pressure is not acting on the pilot chamber 13, the electromagnetic proportional switching valve S configured as described above maintains one switching position, which is the illustrated normal position, by the action of the spring 12. At this one switching position, the supply ports 6a and 6b are closed, and the return ports 7a and 7b are maintained in a state where the throttle opening is maintained. When the pilot pressure is introduced into the pilot chamber 13 as described above and the electromagnetic proportional switching valve S is switched from the normal position to the other switching position, the supply ports 6a and 6b and the return ports 7a and 7b are connected. The opening at that time is controlled according to the exciting current of the solenoid 14a as described above. However, a controller, which is a control mechanism (not shown), controls so that the excitation current of the solenoid 14a and the operation amount of the operation lever 5a of the pilot control mechanism 5 are synchronized.

  In any case, when the electromagnetic proportional switching valve S is in one of the illustrated switching positions, which is the illustrated normal position, no hydraulic oil is guided to the supply flow path 9, so the hydraulic motor M does not rotate. The generator G does not function as well. In this state, when the electromagnetic proportional switching valve S is switched to the other switching position, the pressure oil is guided to the supply flow path 9 and the return flow path 11 communicates with the tank T, so that the hydraulic motor M rotates and the generator Turn G to generate electricity.

  Further, a short-circuit channel 15 that short-circuits both the supply channel 9 and the return channel 11 is provided, and the short-circuit channel 15 is connected to the supply channel 9 from the return channel 11. A check valve 16 that allows only flow is provided. Further, a relief valve 17 is provided in parallel with the check valve 16 so as to control the maximum pressure on the supply flow path 9 side. Note that by making the set pressure of the relief valve 17 variable, the device can be adapted to various generators having different allowable torques. Furthermore, a replenishment flow path 18 is connected to the supply flow path 9 so that the shortage of the flow rate on the supply flow path 9 side is compensated from the tank T. Reference numeral 19 in the figure is a check valve provided in the replenishment flow path 18 and allows only the flow from the tank T to the supply flow path 9.

Next, the operation of the first embodiment will be described. Now, assuming that the switching control valve 2 is maintained at the neutral position shown in the drawing, the operation lever 5a of the pilot control mechanism 5 is operated to switch the switching control valve 2 to the left side of the drawing. The oil discharged from the pump P is supplied, the hydraulic oil in the rod side chamber 1a is returned to the tank T, and the cylinder 1 extends. However, at this time, the controller which is a control mechanism (not shown) does not excite the solenoid 14a in order to keep the electromagnetic proportional switching valve S at one switching position which is the normal position shown.

  When the operation lever 5a of the pilot control mechanism 5 is switched in the opposite direction from the above state and the switching control valve 2 is switched to the right side position in the drawing from the above state, the discharge oil of the pump P is supplied to the rod side chamber 1a. The oil discharged from the side chamber 1b is returned to the tank T. However, at this time, a throttle 20 is formed between the actuator port 2d of the switching control valve 2 and the tank port 2b. The opening of the throttle 20 depends on the switching stroke of the switching control valve 2. To change according to

When the switching control valve 2 is switched to the right side position in the drawing as described above, the controller controls the excitation current supplied to the solenoid 14a according to the switching amount of the switching control valve 2, that is, the opening degree of the throttle 20. To do. Therefore, the switching amount of the electromagnetic proportional switching valve S is controlled according to the opening of the throttle 20, and the switching amount is controlled as follows.

That is, the total flow rate of the flow rate Qt flowing through the tank T through the switching control valve 2 and the flow rate Qm passing through the electromagnetic proportional switching valve S and supplied to the hydraulic motor M is used for the return control of the cylinder 1. It is made equal to the required flow rate Qc. In other words, the total amount Qc of the return flow rate from the cylinder 1 is controlled so as to be the total flow rate of the flow rate Qt passing through the throttle 20 and the flow rate Qm passing through the electromagnetic proportional switching valve S. By controlling the flow rate in this way, the cylinder 1 sensed by the operator between when the energy conversion device having the hydraulic motor M and the generator G as main elements is provided and when the energy conversion device is not provided. The effect that the feeling of operation is almost the same can be expected.

When the electromagnetic proportional switching valve S is switched from one switching position shown in the figure to the other switching position as described above, the return flow rate from the cylinder 1 is throttled by the throttle 20 of the switching control valve 2, and the return flow rate is set. Among them, the pressure oil other than passing through the throttle 20 is guided to the supply flow path 9, so that the hydraulic motor M rotates at the pressure and rotates the generator G to exert the power generation function. The electric power generated in this way is stored in a battery (not shown). When the switching control valve 2 is returned to the neutral position shown in the above state, the cylinder 1 stops and the controller (not shown) functions to set the excitation current of the electromagnetic proportional switching valve S to zero. To do. Therefore, the electromagnetic proportional switching valve S is switched to one switching position, which is the normal position shown.

  When the electromagnetic proportional switching valve S is switched to one of the switching positions, which is the normal position, the supply of pressure oil to the hydraulic motor M is cut off, so the hydraulic motor M attempts to stop, but the hydraulic motor M And the inertial energy of the generator G continues to rotate until the energy is absorbed. When the hydraulic motor M continues to rotate with inertial energy in this way, the hydraulic motor M substantially performs a pumping action. Accordingly, the hydraulic oil is sucked from the supply flow path 9 side and discharged to the return flow path 11 side. However, as described above, the supply ports 6a and 6b of the electromagnetic proportional switching valve S are closed. M cannot sufficiently suck hydraulic oil from the supply flow path 9.

  However, at this time, the hydraulic oil discharged from the hydraulic motor M to the return flow path 11 side is returned to the supply flow path 9 side where the pressure is low via the short-circuit passage 15. In addition, since the hydraulic oil in the tank T is also supplied from the supply flow path 18, the problem that negative pressure is generated on the suction side of the hydraulic 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 electromagnetic proportional switching valve S also substantially turns on and off. Will repeat. However, the hydraulic motor M connected to the generator G having a large inertial energy cannot be stopped and driven in a short time, but in this embodiment, even if the electromagnetic proportional switching valve S is repeatedly turned on and off in a short time. In addition, the inertia energy of the generator G can be absorbed, no negative pressure is generated on the supply flow path 9 side, and naturally no cavitation occurs.

Moreover, even if the electromagnetic proportional switching valve S is suddenly switched to one of the illustrated switching positions, the return ports 7a and 7b maintain the throttle opening, so that a shock is generated in the hydraulic motor M. Nor.

The second embodiment shown in FIG. 2 divides the electromagnetic proportional switching valve S into two parts, a supply-side switching valve S1 and a return-side switching valve S2, and the others are the same as in the first embodiment. It is. Therefore, here, only the configuration of the supply side switching valve S1 and the return side switching valve S2 will be described, and description of other components will be omitted.

  The supply-side switching valve S1 is provided with a spring force of the spring 21 on one side and a pilot chamber 22 on the other side. A pilot pressure control valve 23 is connected to the pilot chamber 22. The pilot pressure control valve 23 controls the pilot pressure according to the exciting current of the solenoid 23a. Therefore, the pilot pressure control valve 23 guides the pilot pressure corresponding to the exciting current of the solenoid 23a to the pilot chamber 22, and the supply side switching valve S1 is switched according to the magnitude of the pilot pressure. The supply-side switching valve S1 thus configured is a two-position two-port valve, and its supply ports 24a and 24b are closed when the supply-side switching valve S1 is at one switching position which is the illustrated normal position, When pilot pressure is applied to the chamber 22, the supply ports 24a and 24b are opened by switching to the other switching position.

  Similarly to the supply-side switching valve 1, the return-side switching valve S2 is provided with a spring 25 and a pilot chamber 26 at a position facing the spring 25, and the pilot pressure led to the pilot chamber 26 is changed to the pilot pressure. Control is performed by the exciting current of the solenoid 27a of the control valve 27. The return side switching valve S2 thus configured is a two-position two-port valve, and its return ports 28a and 28b have a throttle opening degree when the return side switching valve S2 is at one switching position which is the illustrated normal position. In addition, when the pilot pressure is applied to the pilot chamber 26, the return ports 28a and 28b are opened by switching to the other switching position.

  In the second embodiment, the openings of the supply ports 24a and 24b and the return ports 28a and 28b are controlled in the same manner as in the first embodiment by a controller that is a control mechanism (not shown). is there.

  In both the first and second embodiments, when the actuator is a cylinder, inertial energy and potential energy act on the cylinder. However, when the actuator is, for example, a rotary hydraulic motor, Only inertial energy works. Therefore, in the case of a cylinder, both inertial energy and potential energy must be absorbed, but in the case of a hydraulic motor, it is sufficient to absorb only inertial energy.

It is a circuit diagram of a 1st embodiment. It is a circuit diagram of a 2nd embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cylinder which is an actuator S Proportional switching valve S1 Supply side switching valve S2 Return side switching valve 6a, 6b Supply port 24a, 24b Supply port 7a, 7b Return port 28a, 28b Return port M Hydraulic motor G Generator 11 Return flow path 15 Short-circuit channel 16 Check valve 17 Relief valve 18 Supply channel

Claims (4)

  Depending on the switching position of the switching valve, the return flow from the actuator is guided to the hydraulic motor, and the return flow from the hydraulic motor is returned to the tank via the switching valve, while a generator is connected to the hydraulic motor. In the energy conversion device for generating electricity by driving the generator with the rotational force of the hydraulic motor, a short-circuit channel is provided between the supply channel and the return channel connecting the switching valve and the hydraulic motor, and the short-circuit channel An energy conversion device characterized in that a check valve that allows only a flow from a return flow path to a supply flow path is provided in the path, and a supply flow path for supplying hydraulic oil is connected to the supply flow path.   The switching valve is one or a pair of electromagnetic proportional switching valves. The electromagnetic proportional switching valve closes the supply port communicating with the supply flow path, and the return port communicating with the return flow path has a throttle opening degree. 2. The energy conversion device according to claim 1, wherein the energy conversion device has one switching position to be maintained and the other switching position in which the supply port and the return port are electromagnetically opened. Switching control valve for controlling the actuator, the passage comprising a side return when inertial energy and potential energy in the actuator is applied, provided the throttle opening degree is changed in accordance with the switching of the switching control valve, the diaphragm while connecting the passage and the supply port of the solenoid proportional control valve provided, the electromagnetic proportional selector valve, with switches in synchronism with the switching control valve, of the return flow rate Qc from the actuator, the diaphragm A flow rate Qm other than the flow rate Qt that passes through the hydraulic control motor flows through the hydraulic motor, and a flow rate Qt that flows through the throttle of the switching control valve and flows into the tank, and a flow rate that flows through the electromagnetic proportional switching valve and flows into the hydraulic motor. total flow rate of Qm is, the energy of claim 1, wherein was equal configuration to the flow rate Qc required for the actuator of the return control Conversion apparatus.
  The energy conversion device according to any one of claims 1 to 3, wherein a relief valve is provided between the supply channel and the return channel, and the maximum pressure of the supply channel is set by the relief valve.

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