WO2018155244A1

WO2018155244A1 - Energy recovery device and energy recovery method

Info

Publication number: WO2018155244A1
Application number: PCT/JP2018/004725
Authority: WO
Inventors: 前川　智史; 菅野　直紀; 喜雄井上; 元康園部
Original assignee: 株式会社神戸製鋼所; 高知県公立大学法人
Priority date: 2017-02-27
Filing date: 2018-02-09
Publication date: 2018-08-30

Abstract

In order to prevent a reduction in the energy recovery rate caused by flow rate fluctuations in a working fluid in a flow path in an energy recovery device that recovers energy from a working fluid ejected from a fluid chamber, this energy recovery device (1) is equipped with an inertial fluid container (21), a low-pressure-side container (LP), a high-pressure-side container (HP), a low-pressure-side opening/closing device (3L), a high-pressure-side opening/closing device (3H), opening/closing flow paths (31, 32), and an opening/closing device control unit (5). The opening/closing device control unit (5) alternately switches the communication destination of the inertial fluid container (21) between the low-pressure-side container (LP) and the high-pressure-side container (HP) in accordance with a reduction in the volume of a fluid chamber (203), and causes hydraulic oil to flow into the high-pressure-side container (HP) by means of the inertial force generated in the inertial fluid container (21) when the hydraulic oil flows toward the low-pressure-side container (LP). The opening/closing device control unit (5) sets the switching frequency of the opening/closing devices to a frequency close to the Nth (where N is a natural number) antiresonant frequency of the flow path of the hydraulic oil.

Description

Energy recovery device and energy recovery method

The present invention relates to an energy recovery device and an energy recovery method for recovering energy of a working fluid.

Conventionally, the technique described in Patent Document 1 is known as an energy recovery device that recovers the energy of a working fluid. The technology includes an inertial fluid container that communicates with the discharge side of the actuator, and a low-pressure side container and a high-pressure side container that are respectively connected in parallel to the inertial fluid container. Further, a low-pressure side switch composed of a solenoid valve is provided between the inertial fluid container and the low-pressure side container, and a high-pressure side switch composed of a solenoid valve is provided between the inertial fluid container and the high-pressure side container. It has been. In the energy recovery apparatus, when the high-pressure side switch is closed and the low-pressure side switch is opened, the working fluid flows from the inertial fluid container into the low-pressure side container. At this time, the inertial force of the fluid is generated in the inertial fluid container due to the flow of the working fluid. Thereafter, when the low-pressure side switch is closed and the high-pressure side switch is opened, the working fluid flows into the high-pressure side container due to the inertial force of the fluid generated in the inertial fluid container. Thus, the high-pressure side switch and the low-pressure side switch are alternately opened and closed at a high frequency, so that the energy of the working fluid can be recovered in the high-pressure side container.

JP 2014-163419 A

In the technique described in Patent Document 1, when the switching frequency for opening and closing each switch is set to a predetermined value, the working fluid may pulsate due to the opening and closing of the switch. When the pulsation is increased in the actuator and the flow path of the working fluid, there is a problem that the backflow of the working fluid is generated from the high-pressure side container toward the inertial fluid container, and the amount of energy recovery is reduced.

The present invention relates to an energy recovery device that recovers energy of a working fluid discharged from a fluid chamber, an energy recovery device capable of suppressing a decrease in energy recovery rate due to a flow rate fluctuation of the working fluid in a flow path, And an energy recovery method.

What is provided is an energy recovery device that recovers the energy of a working fluid, and the energy recovery device is a fluid chamber in which the working fluid is enclosed, and the volume of the fluid chamber is variable. A first internal space communicating with the fluid chamber, an inertia fluid container for receiving the working fluid discharged from the fluid chamber as the volume of the fluid chamber is reduced, and a lower pressure than the fluid chamber A low pressure side container having a second internal space communicating with the first internal space of the inertial fluid container and receiving the working fluid flowing out from the inertial fluid container; and a pressure higher than the second internal space of the low pressure side container A high-pressure side container that receives the working fluid that has flowed out of the inertial fluid container, and has a third internal space that communicates with the first internal space of the inertial fluid container. A low-pressure side switch that operates to open and close the low-pressure side opening by forming a low-pressure side opening that allows the working fluid to flow between the pressure vessel and the low-pressure side container; A high-pressure side switch that operates to open and close the high-pressure side opening by forming a high-pressure side opening that allows the working fluid to flow to and from the inertial fluid container; and the low-pressure side opening and closing from the inertia fluid container A switch passage that leads to the working fluid and the high-pressure side switch and guides the working fluid, and communicates the inertial fluid container with the low-pressure side container and the high-pressure side according to a reduction in the volume of the fluid chamber By controlling the opening and closing operations of the high-pressure side switch and the low-pressure side switch so as to switch alternately with the container, when the working fluid flows toward the low-pressure side container, the inertial fluid container The inertia generated in the first internal space And a switch control unit for flowing the working fluid to the high pressure side container by the force. The switch controller controls a switching frequency for switching a communication destination of the inertial fluid container between the low-pressure side container and the high-pressure side container, and includes at least the inertial fluid container and the switch channel. It is set to a frequency in the vicinity of the Nth order (N is a natural number) anti-resonance frequency of the flow path.

1 is a schematic hydraulic circuit diagram of an energy recovery device according to a first embodiment of the present invention. It is the graph which showed the relationship between the opening time of the high voltage | pressure side switch and low voltage | pressure side switch with which the energy recovery apparatus which concerns on 1st Embodiment of this invention is equipped, and the opening degree of each switch. In the energy recovery device concerning a 1st embodiment of the present invention, it is a graph which showed an example of the relation (frequency response of flow rate variation) of the frequency of pressure variation which occurs in the flow path of working fluid, and the flow rate variation of working fluid. . It is a graph which shows the time transition of the opening degree of a high voltage | pressure side switch and a low voltage | pressure side switch. It is a graph which shows the time transition of the pressure of the working fluid near the exit of an inertial fluid chamber corresponding to control of the switch shown in Drawing 4A. Time transition of the flow rate of the working fluid near the outlet of the inertial fluid chamber, the flow rate of the working fluid of the high pressure side switch, and the flow rate of the working fluid of the low pressure side switch corresponding to the control of the switch shown in FIG. 4A It is a graph which shows. It is a graph which shows the frequency response of the pressure fluctuation of the working fluid near the exit of an inertial fluid chamber corresponding to control of the switch shown in Drawing 4A. It is a graph which shows the frequency response of the flow volume fluctuation | variation of the working fluid in the vicinity of the exit of an inertial fluid chamber corresponding to control of the switch shown by FIG. 4A. It is a graph which shows the time transition of the opening degree of a high voltage | pressure side switch and a low voltage | pressure side switch. It is a graph which shows the time transition of the pressure of the working fluid near the exit of an inertial fluid chamber corresponding to control of the switch shown in Drawing 5A. Time transition of the working fluid passage flow rate near the outlet of the inertial fluid chamber, the working fluid passage flow rate of the high pressure side switch, and the working fluid passage rate of the low pressure side switch corresponding to the control of the switch shown in FIG. 5A It is a graph which shows. It is a graph which shows the frequency response of the pressure fluctuation of the working fluid near the exit of an inertial fluid chamber corresponding to control of the switch shown in Drawing 5A. It is a graph which shows the frequency response of the flow volume fluctuation | variation of the working fluid near the exit of an inertial fluid chamber corresponding to control of the switch shown by FIG. 5A. It is sectional drawing of the inertial fluid chamber of the energy recovery apparatus which concerns on 2nd Embodiment of this invention. In the energy recovery device concerning a 2nd embodiment of the present invention, it is a graph which showed an example of the relation (frequency response of flow rate fluctuation) of the frequency of the pressure fluctuation which occurs in the flow path of the working fluid, and the flow volume fluctuation of the working fluid. . It is a graph which shows the time transition of the opening degree of a high voltage | pressure side switch and a low voltage | pressure side switch. It is a graph which shows the time transition of the pressure of the working fluid near the exit of an inertial fluid chamber corresponding to control of the switch shown by FIG. 8A. FIG. 8A shows the time transition of the flow rate of the working fluid near the outlet of the inertial fluid chamber, the flow rate of the working fluid of the high-pressure side switch, and the flow rate of the working fluid of the low-pressure side switch, corresponding to the control of the switch shown in FIG. It is a graph which shows. It is a graph which shows the frequency response of the pressure fluctuation | variation of the working fluid in the vicinity of the exit of an inertial fluid chamber corresponding to control of the switch shown by FIG. 8A. It is a graph which shows the frequency response of the flow volume fluctuation | variation of the working fluid near the exit of an inertial fluid chamber corresponding to control of the switch shown by FIG. 8A. It is a graph which shows the time transition of the opening degree of a high voltage | pressure side switch and a low voltage | pressure side switch. It is a graph which shows the time transition of the pressure of the working fluid near the exit of an inertial fluid chamber corresponding to control of the switch shown by FIG. 9A. FIG. 9A shows a time transition of the flow rate of the working fluid near the outlet of the inertial fluid chamber, the flow rate of the working fluid of the high-pressure side switch, and the flow rate of the working fluid of the low-pressure side switch, corresponding to the control of the switch shown in FIG. It is a graph which shows. It is a graph which shows the frequency response of the pressure fluctuation of the working fluid near the exit of an inertial fluid chamber corresponding to control of the switch shown in Drawing 9A. It is a graph which shows the frequency response of the flow volume fluctuation | variation of the working fluid in the vicinity of the exit of an inertial fluid chamber corresponding to control of the switch shown by FIG. 9A. It is sectional drawing of the inertial fluid chamber of the energy recovery apparatus which concerns on 3rd Embodiment of this invention. In the energy recovery apparatus according to the third embodiment of the present invention, the first example of the relationship (frequency response of flow rate fluctuation) between the frequency of pressure fluctuation generated in the flow path of the working fluid and the flow rate fluctuation of the working fluid is shown. It is a graph. In the energy recovery device according to the third embodiment of the present invention, the second example of the relationship between the frequency of the pressure fluctuation generated in the flow path of the working fluid and the flow fluctuation of the working fluid (frequency response of the flow fluctuation) is shown. It is a graph. It is a graph which shows the time transition of the opening degree of a high voltage | pressure side switch and a low voltage | pressure side switch. It is a graph which shows the time transition of the pressure of the working fluid near the exit of an inertial fluid chamber corresponding to control of the switch shown in Drawing 13A. The time transitions of the flow rate of the working fluid near the outlet of the inertial fluid chamber, the flow rate of the working fluid of the high-pressure side switch, and the flow rate of the working fluid of the low-pressure side switch corresponding to the control of the switch shown in FIG. 13A It is a graph which shows. It is a graph which shows the frequency response of the pressure fluctuation | variation of the working fluid in the vicinity of the exit of an inertial fluid chamber corresponding to control of the switch shown by FIG. 13A. It is a graph which shows the frequency response of the flow fluctuation of the working fluid near the exit of an inertial fluid chamber corresponding to control of the switch shown in Drawing 13A. It is a graph which shows the time transition of the opening degree of a high voltage | pressure side switch and a low voltage | pressure side switch. It is a graph which shows the time transition of the pressure of the working fluid near the exit of an inertial fluid chamber corresponding to control of the switch shown in Drawing 14A. FIG. 14A shows a time transition of the flow rate of the working fluid near the outlet of the inertial fluid chamber, the flow rate of the working fluid of the high-pressure side switch, and the flow rate of the working fluid of the low-pressure side switch, corresponding to the control of the switch shown in FIG. It is a graph which shows. It is a graph which shows the frequency response of the pressure fluctuation of the working fluid near the exit of an inertial fluid chamber corresponding to control of the switch shown in Drawing 14A. It is a graph which shows the frequency response of the flow volume fluctuation | variation of the working fluid in the vicinity of the exit of an inertial fluid chamber corresponding to control of the switch shown by FIG. 14A. 2 is a graph showing the time transition of the flow rate of hydraulic oil in the vicinity of the outlet of the inertial fluid chamber in the energy recovery device shown in FIG. 1. 2 is a graph showing the time transition of the flow rate of hydraulic oil in the vicinity of the outlet of the inertial fluid chamber in the energy recovery device shown in FIG. 1. 2 is a graph showing the time transition of the flow rate of hydraulic oil in the vicinity of the outlet of the inertial fluid chamber in the energy recovery device shown in FIG. 1. 2 is a graph showing the time transition of the flow rate of hydraulic oil in the vicinity of the outlet of the inertial fluid chamber in the energy recovery device shown in FIG. 1. 2 is a graph showing the time transition of the flow rate of hydraulic oil in the vicinity of the outlet of the inertial fluid chamber in the energy recovery device shown in FIG. 1. 2 is a graph showing the time transition of the flow rate of hydraulic oil in the vicinity of the outlet of the inertial fluid chamber in the energy recovery device shown in FIG. 1. 2 is a graph showing the time transition of the flow rate of hydraulic oil in the vicinity of the outlet of the inertial fluid chamber in the energy recovery device shown in FIG. 1. It is the graph which expanded the periphery of the antiresonance frequency (primary) and the resonance frequency (primary) among the graphs of FIG.

Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic hydraulic circuit diagram of an energy recovery device 1 according to the present embodiment. FIG. 2 is a graph showing the relationship between the opening time of the high-pressure side switch and the low-pressure side switch provided in the energy recovery device 1 according to this embodiment and the opening degree of each switch. The energy recovery device 1 recovers the energy of the working fluid. Examples of the working fluid include hydraulic oil, water, and air, but are not particularly limited. Hereinafter, in a hydraulic circuit (fluid circuit) connected to the hydraulic cylinder, energy input to the hydraulic cylinder is converted into hydraulic oil energy, and the energy recovery device 1 recovers the energy of the hydraulic oil. To do.

Referring to FIG. 1, an energy recovery apparatus 1 includes a hydraulic cylinder 20, an inertia fluid chamber 21 (inertia fluid container), a low pressure side switch 3L, a high pressure side switch 3H, and a low pressure source LP (low pressure side container). ), A high pressure source HP (high pressure side container), and a control unit 5 (switch control unit).

The hydraulic cylinder 20 includes a cylindrical cylinder body 201 and a piston 202 that can reciprocate within the cylinder body 201. A rod 202 A is connected to one end side of the piston 202. The piston 202 partitions the internal space of the cylinder body 201 into a piston side chamber 203 (fluid chamber) and a rod side chamber 204. The hydraulic cylinder 20 can input and output energy with the outside through the rod 202A. At least the piston side chamber 203 of the hydraulic cylinder 20 is filled with hydraulic oil. As shown in FIG. 1, when an external force F is applied to the rod 202A, the piston 202 moves so that the volume of the piston side chamber 203 is reduced. As a result, the hydraulic oil in the piston side chamber 203 flows out from the hydraulic cylinder 20 and flows into the inertial fluid chamber 21. The piston side chamber 203 constitutes a fluid chamber of the present invention. The piston side chamber 203 is filled with hydraulic oil, and the volume of the piston side chamber 203 is variable.

The inertial fluid chamber 21 includes a cylindrical internal space (first internal space) communicating with the piston side chamber 203 of the hydraulic cylinder 20. The inertial fluid chamber 21 receives the hydraulic oil discharged from the piston side chamber 203 that is contracted as the piston 202 moves. As an example, in the present embodiment, the inertial fluid chamber 21 has a pipe shape, and the inertial fluid chamber 21 has a circular cross-sectional shape. The inertia fluid chamber 21 is a cylindrical member (straight pipe shape) extending linearly along the direction of the flow of hydraulic oil. The volume of the internal space of the inertial fluid chamber 21 is smaller than the volume of the internal space of the hydraulic cylinder 20. The internal space of the inertial fluid chamber 21 is filled with hydraulic oil. A low pressure pipe PL and a high pressure pipe PH are connected in parallel to a fluid chamber outlet 210 that is an outlet of the inertial fluid chamber 21. In other words, the flow path connected to the fluid chamber outlet 210 is branched into two immediately after the fluid chamber outlet 210.

The low pressure source LP is connected to the end of the low pressure pipe PL. The low-pressure source LP has an internal space (second internal space). The internal space of the low pressure source LP communicates with the inertial fluid chamber 21 via the low pressure pipe PL. The low pressure source LP receives the hydraulic oil that has flowed out of the inertial fluid chamber 21. The low pressure source LP is, for example, a tank for storing hydraulic oil. The internal space of the low pressure source LP is normally kept at atmospheric pressure. As a result, the pressure of the hydraulic oil in the low pressure source LP is substantially equal to the atmospheric pressure, and is set to be lower than the internal pressure of the piston side chamber 203.

The low pressure side switch 3L is disposed between the inertial fluid chamber 21 and the low pressure source LP. The low pressure side switch 3L is a solenoid valve. The low pressure side switch 3L forms an unillustrated opening (low pressure side opening) that permits the flow of hydraulic oil between the inertial fluid chamber 21 and the low pressure source LP, and opens and closes the opening. Operate. That is, the low pressure side switch 3L communicates and blocks the inertial fluid chamber 21 and the low pressure source LP.

The high pressure source HP is connected to the end of the high pressure pipe PH. The high pressure source HP includes an internal space (third internal space). The internal space of the high pressure source HP communicates with the inertial fluid chamber 21 via the high pressure pipe PH. The high pressure source HP receives the hydraulic fluid that has flowed out of the inertial fluid chamber 21. The high pressure source HP may be a tank in which hydraulic oil having a higher pressure than the low pressure source LP is accumulated, or an accumulator. Further, the internal space of the high-pressure source HP is set to a pressure higher than at least the internal space of the low-pressure source LP. In this embodiment, the internal space is set to a pressure higher than the pressure of the piston-side chamber 203.

The high-pressure side switch 3H is disposed between the inertial fluid chamber 21 and the high-pressure source HP. The high-pressure side switch 3H is a solenoid valve. The high-pressure side switch 3H forms an opening (not shown) (low-pressure side opening) that allows the working oil to flow between the inertial fluid chamber 21 and the high-pressure source HP, and opens and closes the opening. Operate. That is, the high-pressure side switch 3H communicates and blocks the inertial fluid chamber 21 and the high-pressure source HP.

In the low-pressure pipe PL, a region from the fluid chamber outlet 210 to the opening of the low-pressure side switch 3L is defined as a low-pressure side branch 31. Further, a region from the fluid chamber outlet 210 to the opening of the high-pressure side switch 3 H in the high-pressure pipe PH is defined as a high-pressure side branch path 32. The low-pressure side branch path 31 and the high-pressure side branch path 32 constitute the switch channel of the present invention. The switch channel is a channel (pipe) that is arranged so as to branch from the fluid chamber outlet 210 of the inertial fluid chamber 21 and guides hydraulic oil to the low pressure side switch 3L and the high pressure side switch 3H. .

The control unit 5 controls the operation of the high pressure side switch 3H and the low pressure side switch 3L. The control unit 5 has a function of instructing the switching timing to the high voltage side switch 3H and the low voltage side switch 3L. The control unit 5 controls the low-pressure side switch 3L and the high-pressure side opening / closing so that the communication destination of the inertial fluid chamber 21 is alternately switched between the low-pressure source LP and the high-pressure source HP according to the reduction in the volume of the piston-side chamber 203. The opening / closing operation of the device 3H is controlled.

In the energy recovery apparatus 1, when the control unit 5 closes the opening of the high-pressure side switch 3H and opens the opening of the low-pressure side switch 3L, the hydraulic oil in the inertial fluid chamber 21 flows into the low-pressure source LP. At this time, a fluid inertia force is generated in the internal space of the inertial fluid chamber 21 by the flow of the hydraulic oil. Next, when the controller 5 closes the opening of the low pressure side switch 3L and opens the opening of the high pressure side switch 3H, the high pressure source HP is generated by the inertial force of the fluid generated in the inertia fluid chamber 21 as described above. The hydraulic oil can be poured into and accumulated. Even if the pressure of the high-pressure source HP is equal to or higher than the pressure of the inertial fluid chamber 21, the hydraulic oil is poured into the high-pressure source HP and accumulated while the inertial force of the fluid is maintained in the inertial fluid container 21. Can do. That is, when an external force F is applied to the hydraulic cylinder 20 as shown in FIG. 1, the control unit 5 controls the low pressure side switch 3L and the high pressure side switch 3H, so that the energy of the external force F is recovered in the high pressure source HP. can do.

Note that the inertial force of the fluid in the inertial fluid chamber 21 decreases with time. For this reason, the control part 5 can recover the inertial force of the fluid by closing the high pressure side switch 3H again and opening the low pressure side switch 3L. For this reason, the control part 5 switches the switching period of the low voltage | pressure side switch 3L and the high voltage | pressure side switch 3H alternately with a predetermined period. According to such a configuration, even when the pressure of the high pressure source HP is equal to or higher than the pressure of the piston side chamber 203 of the hydraulic cylinder 20, energy can be regenerated and accumulated in the high pressure source HP. The recovered energy may be used again as energy for driving the hydraulic cylinder 20 or may be regenerated as other energy. As an example, the energy of the hydraulic oil recovered by the high pressure source HP may be supplied to a hydraulic device (a hydraulic motor or a hydraulic pump) (not shown).

Referring to FIG. 2, when performing the energy recovery operation, control unit 5 alternately switches the opening and closing operations of low-pressure side switch 3L and high-pressure side switch 3H at high speed. Specifically, the control unit 5 includes a control current output unit, a PWM converter, and a drive circuit. The control current output unit outputs a pulse signal for controlling the switching operation of the low voltage side switch 3L and the high voltage side switch 3H. Here, the pulse signal is composed of a predetermined rectangular wave, and the open / close times of the low-voltage side switch 3L and the high-voltage side switch 3H are controlled by the duty ratio d of the pulse signal. Referring to FIG. 2, the duty ratio d is defined by the following equation 1.
d = T2 / T1 (Formula 1)
Here, T1 is a time (cycle) per cycle of opening / closing of the low-voltage side switch 3L and the high-voltage side switch 3H, and T2 is a time during which the high-voltage side switch 3H is open in one cycle. That is, the duty ratio d defined by Equation 1 corresponds to the high-pressure side duty ratio d1 for controlling the opening time of the high-pressure side opening 3H within the period T1. The time during which the low pressure side switch 3L is open corresponds to T1-T2 in FIG. Therefore, the low-pressure side duty ratio d2 for controlling the opening time of the low-pressure side opening 3L within the period T1 corresponds to 1-d1. Note that the frequency of the pulse signal is controlled as a switching frequency described later.

As shown in FIG. 1, the flow path of the hydraulic oil discharged from the piston side chamber 203 of the hydraulic cylinder 20 includes a flow path (low pressure pipe PL) from the inertia fluid chamber 21 to the low pressure source LP and a high pressure from the inertia fluid chamber 21. And a flow path (high-pressure pipe PH) to the source HP. Since these flow paths are composed of piping or the like, predetermined vibrations are generated according to the flow of hydraulic oil. In addition, when the flow path shown in FIG. 1 is a complete rigid body, such vibration does not occur. The vibration of the flow path (pipe) causes pulsation of the hydraulic oil and affects the flow of the hydraulic oil.

FIG. 3 is a graph showing an example of the relationship (frequency response of flow rate fluctuation) between the frequency of pressure fluctuation generated in the flow path of hydraulic fluid and the flow rate fluctuation of hydraulic oil in the energy recovery apparatus 1 according to the present embodiment. is there. Specifically, in FIG. 1, the high pressure source HP with the opening of the high pressure side switch 3H fully opened (free end) and the opening of the low pressure side switch 3L fully closed (fixed end). A pressure fluctuation that fluctuates in a sine wave is forcibly applied. FIG. 3 is a waveform showing the flow rate fluctuation (frequency response) of the hydraulic oil in the vicinity of the fluid chamber outlet 210 of the inertial fluid chamber 21 in this case. Note that the data in FIG. 3 may be calculated by simulation, or may be measured by a flow meter provided as a test near the fluid chamber outlet 210.

Referring to FIG. 3, the magnitude of the flow rate variation of the hydraulic oil varies depending on the frequency of the applied pressure variation from the vibration characteristics provided in the entire hydraulic fluid flow path of FIG. 1. Here, “1” shown in the graph of FIG. 3 is the anti-resonance primary frequency of the flow path (system), “2” is the resonance primary frequency, and “3” is the anti-resonance secondary frequency. Yes, "4" is the resonant secondary frequency. Thus, the anti-resonance frequency and the resonance frequency appear alternately. As shown in FIG. 3, the fluctuation in the flow rate of the hydraulic oil at the resonance frequency is a maximum value, and the fluctuation in the flow rate of the hydraulic oil at the anti-resonance frequency is a minimum value. In general, if the inertial fluid chamber 21 has a shape having a linear and uniform cross section, the resonance frequency is twice the antiresonance frequency. Also in FIG. 3, the resonance primary frequency “2” is approximately twice the anti-resonance primary frequency “1”. As described above, since the inertial fluid chamber 21 is branched from the high-pressure side switch 3H and the low-pressure side switch 3L, the resonance primary frequency “2” is actually anti-resonance. There is a slight deviation from twice the primary frequency “1”. In the present invention, as a result of newly finding such a tendency of the flow rate variation of the hydraulic oil, the switching frequency f in the control of the low pressure side switch 3L and the high pressure side switch 3H by the control unit 5 is suitably set.

That is, in FIG. 1, when recovering the energy of the hydraulic oil discharged from the hydraulic cylinder 20 to the high pressure source HP, when the openings of the low pressure side switch 3L and the high pressure side switch 3H are sequentially opened and closed, the openings Opening and closing the valve causes pressure fluctuations in the hydraulic oil flow path. Therefore, in the present embodiment, the switching frequency f of the high-pressure side switch 3H and the low-pressure side switch 3L is determined from the anti-resonance points (“1”, “3”... Is set near the frequency. That is, the control unit 5 sets at least the inertia fluid chamber 21 and the switch channel (the low-pressure side branch channel 31, the high-pressure channel 31) to switch the communication destination of the inertia fluid chamber 21 between the low pressure source LP and the high pressure source HP. The frequency is set in the vicinity of the Nth-order (N is a natural number) anti-resonance frequency of the hydraulic oil flow path including the side branch path 32). As a result, as shown in FIG. 3, it is possible to reduce fluctuations in the flow rate of the hydraulic oil as compared with other frequency regions.

<When switching frequency is set to anti-resonance frequency (duty ratio d = 0.5)>
Hereinafter, in the energy recovery apparatus 1 shown in FIG. 1, an example of controlling the opening operation of the high-pressure side switch 3H and the low-pressure side switch 3L is shown. FIG. 4 shows the transition of each characteristic value when the switching frequency f of the high-voltage side switch 3H and the low-voltage side switch 3L is set to the anti-resonance primary frequency (frequency “1” in FIG. 3 = 88 Hz). It is a graph. FIG. 4A is a graph showing time transitions of the opening degrees of the high-pressure side switch 3H and the low-pressure side switch 3L. In FIG. 4A, the aforementioned duty ratio d = 0.5. 4B to 4E correspond to the control of the switch shown in FIG. 4A. FIG. 4B is a graph showing the time transition of the hydraulic oil pressure in the vicinity of the fluid chamber outlet 210 of the inertial fluid chamber 21. FIG. 4C is a graph showing the time transition of the flow rate of hydraulic oil in the vicinity of the fluid chamber outlet 210 of the inertial fluid chamber 21, the flow rate of hydraulic oil in the high pressure side switch 3H, and the flow rate of hydraulic fluid in the low pressure side switch 3L. It is. FIG. 4D is a graph showing the frequency response of the hydraulic oil pressure fluctuation (FIG. 4B) in the vicinity of the fluid chamber outlet 210 of the inertial fluid chamber 21. In other words, FIG. 4D shows the result of processing the pressure fluctuation data of FIG. 4B by a known frequency analysis (the same applies to FIGS. 5D, 8D, 9D, 13D, and 14D). FIG. 4E is a graph showing the frequency response of the flow rate fluctuation (FIG. 4C) of the hydraulic oil in the vicinity of the fluid chamber outlet 210 of the inertial fluid chamber 21. In other words, FIG. 4E shows the result of processing the flow rate fluctuation data in the vicinity of the fluid chamber outlet 210 in FIG. 4C by known frequency analysis (hereinafter, FIG. 5E, FIG. 8E, FIG. 9E, FIG. 13E and FIG. The same applies to 14E). 4A to 4C, a region H is a time during which only the high-pressure side switch 3H is opened and the inertial fluid chamber 21 communicates with the high-pressure source HP. This corresponds to the time for the hydraulic oil to flow toward (the high-pressure side switch passage flow rate is +). Region L is a time during which only the low-pressure side switch 3L is opened and the inertial fluid chamber 21 communicates with the low-pressure source LP, and hydraulic oil flows from the inertial fluid chamber 21 toward the low-pressure source LP in setting. Corresponds to time (the low-pressure side switch passage flow rate is +). The definition of the regions H and L is the same in the later graphs.

Referring to FIG. 4C, most of the hydraulic oil flowing out from the fluid chamber outlet 210 of the inertial fluid chamber 21 passes through the low pressure side switch 3L and the high pressure side switch 3H in order. 4D, when the duty ratio d = 0.5 in the opening control of the low pressure side switch 3L and the high pressure side switch 3H, the excitation frequency at which the pressure fluctuation occurs is the switching frequency (88 Hz). 1 times ("arrow 1" in FIG. 4D), 3 times ("arrow 2" in FIG. 4D), 5 times ("arrow 3" in FIG. 4D), and an odd multiple of the fundamental frequency (= switching frequency) is there. As a result, as shown in FIG. 4E, in the frequency response of the flow fluctuation in the vicinity of the fluid chamber outlet 210 of the inertial fluid chamber 21, the frequency component that is an odd multiple of the fundamental frequency is gradually excited. In other words, in this case, the excitation frequency deviates from the resonance primary frequency of the system (arrow “2” in FIG. 3). For this reason, the flow fluctuation | variation of the hydraulic fluid of the fluid chamber exit 210 vicinity of the inertial fluid chamber 21 can be suppressed. As a result, when recovering the energy of the hydraulic oil to the high pressure source HP, it is possible to suppress a decrease in the energy recovery rate due to the flow fluctuation (pulsation) of the hydraulic oil.

<When switching frequency is set to resonance frequency (duty ratio d = 0.5)>
FIG. 5 is a graph showing the transition of each characteristic value when the switching frequency of the high-voltage side switch 3H and the low-voltage side switch 3L is set to the resonance primary frequency (arrow “2” = 167 Hz in FIG. 3). is there. FIG. 5A is a graph showing the time transition of the opening degree of the high-pressure side switch 3H and the low-pressure side switch 3L. In FIG. 5A, the aforementioned duty ratio d = 0.5. 5B to 5E correspond to the control of the switch shown in FIG. 5A. FIG. 5B is a graph showing the time transition of the pressure of the hydraulic oil in the vicinity of the fluid chamber outlet 210 of the inertial fluid chamber 21. FIG. 5C is a graph showing the time transition of the flow rate of hydraulic oil in the vicinity of the fluid chamber outlet 210 of the inertial fluid chamber 21, the flow rate of hydraulic oil in the high pressure side switch 3H, and the flow rate of hydraulic fluid in the low pressure side switch 3L. It is. FIG. 5D is a graph showing the frequency response of hydraulic oil pressure fluctuation (FIG. 5B) in the vicinity of the fluid chamber outlet 210 of the inertial fluid chamber 21. FIG. 5E is a graph showing the frequency response of the flow rate variation (FIG. 5C) of the hydraulic oil in the vicinity of the fluid chamber outlet 210 of the inertial fluid chamber 21.

Referring to FIG. 5C, in region H, inertial fluid chamber 21 is in communication with high pressure source HP, but hydraulic oil flows backward from high pressure source HP toward inertial fluid chamber 21 (high pressure side). The flow rate through the switch is-). This phenomenon is caused by the fact that the switching fluctuation f of each switch is set to the resonance primary frequency of the system, so that the flow fluctuation of the resonance primary frequency component is greatly excited as shown in FIG. 5E (FIG. 5E). Arrow “1”). In this case, it becomes difficult to prevent a decrease in the amount of recovered energy when recovering the energy of the hydraulic oil.

As described above, in the present embodiment, the control unit 5 sets at least the inertia fluid chamber 21 and the switch flow path to the switching frequency f for switching the communication destination of the inertia fluid chamber 21 between the low pressure source LP and the high pressure source HP. The frequency is set in the vicinity of the Nth-order (N is a natural number) anti-resonance frequency of the hydraulic oil flow path including the (low pressure side branch path 31 and high pressure side branch path 32). For this reason, the fluctuation | variation of the flow volume of the working oil which generate | occur | produces with the resonance of the flow path of the working oil containing the inertial fluid chamber 21 and the switch flow path can be suppressed. As a result, it is possible to suppress a decrease in the energy recovery rate due to fluctuations in the flow rate of the hydraulic oil in the flow path.

Particularly, it is desirable that the control unit 5 sets the switching frequency f to a frequency in the vicinity of the primary anti-resonance frequency of the hydraulic oil flow path. In this case, it is possible to further suppress the fluctuation in the flow rate of the hydraulic oil that occurs due to the resonance of the flow path of the hydraulic oil including the inertial fluid chamber 21 and the switch flow path (the low pressure side branch path 31 and the high pressure side branch path 32). it can.

Next, a second embodiment of the present invention will be described. Note that the present embodiment is different from the first embodiment in that an inertial fluid chamber 22 is provided in place of the inertial fluid chamber 21, so that the difference will be mainly described and common points will be described. The description of is omitted.

In this embodiment, the energy recovery device 1 (FIG. 1) includes an inertial fluid chamber 22. FIG. 6 is a cross-sectional view of the inertial fluid chamber 22. Region (A) in FIG. 6 corresponds to a cross-sectional view of inertial fluid chamber 22 cut along the longitudinal direction (direction in which hydraulic fluid flows), and region (B) represents inertial fluid chamber 22 in the radial direction (operational). This corresponds to a cross-sectional view taken along the direction in which the oil flows.

The inertial fluid chamber 22 has a cylindrical internal space communicating with the piston side chamber 203 of the hydraulic cylinder 20 (FIG. 1). The inertial fluid chamber 22 receives hydraulic oil discharged from the piston side chamber 203 as the piston 202 moves. As an example, in the present embodiment, the inertial fluid chamber 22 has a pipe shape, and the inertial fluid chamber 22 has a circular cross-sectional shape. The volume of the internal space of the inertial fluid chamber 22 is smaller than the volume of the internal space of the hydraulic cylinder 20. The internal space of the inertial fluid chamber 22 is filled with hydraulic oil. A fluid chamber inlet 220 A that is an inlet of the inertial fluid chamber 22 communicates with the piston-side chamber 203 of the hydraulic cylinder 20. Further, a low pressure pipe PL and a high pressure pipe PH (FIG. 1) are connected in parallel to the fluid chamber outlet 220B which is the outlet of the inertial fluid chamber 22.

The inertial fluid chamber 22 includes a first fluid chamber 221 (first conduit), a second fluid chamber 222 (third conduit), and an intermediate fluid chamber 223 (second conduit). The inner diameter of the intermediate fluid chamber 223 is set larger than the inner diameters of the first fluid chamber 221 and the second fluid chamber 222. Further, the axial length of the intermediate fluid chamber 223 is set to about one-fourth of the entire inertial fluid chamber 22. The cross-sectional area of the intermediate fluid chamber 223 is preferably set to 2 to 3 times the cross-sectional areas of the first fluid chamber 221 and the second fluid chamber 222. Note that the inner diameter of the first fluid chamber 221 and the inner diameter of the second fluid chamber 222 may be the same or different from each other. In the following description, the inner diameter of the first fluid chamber 221 and the inner diameter of the second fluid chamber 222 are set to the same value. In the present embodiment, as an example, if the total length of the inertial fluid chamber 22 in the direction of hydraulic oil flow is L, the length of the first fluid chamber 221 is four times 15 times the length of the second fluid chamber 222. The length of the intermediate fluid chamber 223 is set to eight times of 15 times L and the length of the intermediate fluid chamber 223 is set to three times of 15 times L. As an example, L = 3000 (mm).

FIG. 7 is a graph showing an example of the relationship (frequency response of flow rate fluctuation) between the frequency of pressure fluctuation generated in the hydraulic oil flow path and the flow fluctuation of hydraulic oil in the energy recovery apparatus 1 according to the present embodiment. Yes, corresponding to FIG. 3 of the first embodiment. That is, in FIG. 1, the inertial fluid chamber 22 is arranged instead of the inertial fluid chamber 21, the opening of the high-pressure side switch 3H is fully opened (free end), and the opening of the low-pressure side switch 3L is fully closed ( In the state of the fixed end, a pressure fluctuation that fluctuates in a sine wave is forcibly applied to the high-pressure source HP. FIG. 7 is a waveform showing the flow rate fluctuation (frequency response) of the hydraulic oil in the vicinity of the fluid chamber outlet 220B of the inertial fluid chamber 22 in this case. Note that the data in FIG. 7 may be calculated by simulation, as in FIG. 3, or may be measured by a flow meter provided as a test near the fluid chamber outlet 220B.

Referring to FIG. 7, the magnitude of the flow rate variation of the hydraulic oil varies depending on the frequency of the applied pressure variation from the vibration characteristics provided in the entire hydraulic fluid flow path. Here, “1” shown in the graph of FIG. 7 is the anti-resonance primary frequency of the flow path (system), “2” is the resonance primary frequency, and “3” is the anti-resonance secondary frequency. Yes, "4" is the resonant secondary frequency. Thus, also in FIG. 7, the antiresonance frequency and the resonance frequency appear alternately.

On the other hand, in the result of FIG. 7, the resonance primary frequency “2” is smaller than twice the anti-resonance primary frequency “1”. In other words, the frequency “2 ′” which is twice the anti-resonance primary frequency “1” is arranged at a position shifted from the resonance primary frequency. Therefore, when the anti-resonance primary frequency of the system is set to the fundamental frequency (= switching frequency f), the secondary frequency of the fundamental frequency can be removed from the resonance primary frequency of the system. In the case of FIG. 7, there is a possibility that the resonance secondary frequency “2 ′” of the system is close to the higher order frequency of the third or higher fundamental frequency. Since the magnitude of the resonant secondary frequency component is smaller than the magnitude of the resonant primary frequency component of the flow fluctuation, the influence is small.

Hereinafter, the result of comparison between the inertial fluid chamber 21 of FIG. 1 and the inertial fluid chamber 22 of FIG. 6 at a duty ratio d = 0.75 will be described.

<When switching frequency f is set to anti-resonance frequency with respect to inertial fluid chamber 21 (duty ratio d = 0.75)>
FIG. 8 shows an anti-resonance of the switching frequency f of the high-pressure side switch 3H and the low-pressure side switch 3L at the duty ratio d = 0.75 in the energy recovery device 1 including the inertial fluid chamber 21 shown in FIG. It is the graph which showed transition of each characteristic value at the time of setting to a primary frequency (frequency "1" of Drawing 3 = 88Hz). In addition, FIG. 8A is a graph which shows the time transition of the opening degree of the high voltage | pressure side switch 3H and the low voltage | pressure side switch 3L. 8B to 8E correspond to the control of the switch shown in FIG. 8A. FIG. 8B is a graph showing the time transition of the pressure fluctuation of the hydraulic oil in the vicinity of the fluid chamber outlet 210 of the inertial fluid chamber 21. FIG. 8C is a graph showing the time transition of the flow rate of hydraulic oil in the vicinity of the fluid chamber outlet 210 of the inertial fluid chamber 21, the flow rate of hydraulic oil in the high pressure side switch 3H, and the flow rate of hydraulic fluid in the low pressure side switch 3L. It is. FIG. 8D is a graph showing the frequency response of hydraulic oil pressure fluctuation (FIG. 8B) in the vicinity of the fluid chamber outlet 210 of the inertial fluid chamber 21. FIG. 8E is a graph showing the frequency response of the flow rate fluctuation (FIG. 8C) of the hydraulic oil in the vicinity of the fluid chamber outlet 210 of the inertial fluid chamber 21.

A region H in FIG. 8C is a state where the inertial fluid chamber 21 communicates with the high-pressure source HP, but there is a time during which the hydraulic oil flows backward from the high-pressure source HP toward the inertial fluid chamber 21 (the high-pressure side). The flow rate through the switch is-). As shown in FIG. 8D, when the duty ratio d = 0.75, unlike the case where the duty ratio d = 0.5, the excitation frequency generated in the system includes an even number in addition to a frequency that is an odd multiple of the switching frequency. Double frequency is included. That is, the excitation frequency is an integral multiple of the fundamental frequency (= switching frequency f) (arrows “1”, “2”, “3” in FIG. 8D). Further, since the inertial fluid chamber 21 has a linear and uniform cross-sectional shape, the resonance frequency is twice the anti-resonance frequency. For this reason, the resonance primary frequency (arrow “2” in FIG. 8D) exists near the secondary frequency (double frequency) of the fundamental frequency (arrow “1” in FIG. 8D). As a result, the secondary component of the fundamental frequency of flow fluctuation (arrow “2” in FIG. 8E) is greatly excited, and a backflow of hydraulic oil occurs. In this case, it becomes difficult to prevent a decrease in the amount of recovered energy when recovering the energy of the hydraulic oil.

<When switching frequency f is set to an anti-resonance frequency with respect to inertia fluid chamber 22 (duty ratio d = 0.75)>
On the other hand, FIG. 9 group shows the switching frequency f of the high pressure side switch 3H and the low pressure side switch 3L at the duty ratio d = 0.75 in the energy recovery device 1 having the inertial fluid chamber 22 shown in FIG. It is the graph which showed transition of each characteristic value at the time of setting to an antiresonance primary frequency (frequency "1" of Drawing 3 = 88Hz). In addition, FIG. 9A is a graph which shows the time transition of the opening degree of the high voltage | pressure side switch 3H and the low voltage | pressure side switch 3L. 9B to 9E correspond to the control of the switch shown in FIG. 9A. FIG. 9B is a graph showing the time transition of the pressure fluctuation of the hydraulic oil in the vicinity of the fluid chamber outlet 220B of the inertial fluid chamber 22. FIG. 9C is a graph showing the time transition of the flow rate of hydraulic oil in the vicinity of the fluid chamber outlet 220B of the inertial fluid chamber 22, the flow rate of hydraulic oil in the high pressure side switch 3H, and the flow rate of hydraulic fluid in the low pressure side switch 3L. It is. FIG. 9D is a graph showing the frequency response of hydraulic oil pressure fluctuation (FIG. 9B) in the vicinity of the fluid chamber outlet 220 B of the inertial fluid chamber 22. FIG. 9E is a graph showing the frequency response of the flow rate fluctuation (FIG. 9C) of the hydraulic oil in the vicinity of the fluid chamber outlet 220B of the inertial fluid chamber 22.

Region H in FIG. 9C is a state where the inertial fluid chamber 22 communicates with the high-pressure source HP, and there is a time during which hydraulic oil flows backward from the high-pressure source HP toward the inertial fluid chamber 22 (high-pressure side opening / closing). The flow rate through the container is-). However, in FIG. 9C, the backflow of the hydraulic oil is less than in FIG. 8C. Also in this case, as shown in FIG. 9D, when the duty ratio is d = 0.75, the excitation frequency is an integral multiple of the fundamental frequency (= switching frequency) (arrows “1”, “1” in FIG. 9D). 2 "," 3 "). However, since the inertial fluid chamber 21 includes the intermediate fluid chamber 223, the secondary frequency of the fundamental frequency (arrow “2 ′” in FIG. 7) from the resonance primary frequency of the system (arrow “2” in FIG. 7), FIG. 9D arrow “2”) is off (shifted). For this reason, the secondary frequency component (arrow “2” in FIG. 9E) of the fundamental frequency of flow fluctuation in FIG. 9E is smaller than the arrow “2” in FIG. 8E. As a result, as shown in FIG. 9C, the flow rate of the working oil that flows backward is smaller than that in FIG. 8C, and a decrease in the energy recovery amount is suppressed when the energy of the working oil is recovered.

As described above, in the present embodiment, the inertial fluid chamber 22 has a frequency that is twice the primary anti-resonance frequency of the hydraulic oil flow path deviates from the primary resonant frequency of the hydraulic oil flow path. It has a shape. For this reason, even when a frequency twice as high as the primary anti-resonance frequency of the hydraulic oil flow path is excited, fluctuations in the flow volume of the hydraulic oil that occur due to resonance of the hydraulic oil flow path are suppressed. be able to.

In particular, the inertial fluid chamber 22 is a cylindrical member extending along the direction of hydraulic oil flow, and includes a first fluid chamber 221 (first pipe line) communicating with the piston-side chamber 203, and a first fluid chamber 221. To the intermediate fluid chamber 223 (second pipe) having an inner diameter larger than that of the first fluid chamber 221, and to the intermediate fluid chamber 223 and the switch channel (low pressure side branch channel 31, high pressure side branch channel 32). And a second fluid chamber 222 (third pipe line) having an inner diameter smaller than that of the intermediate fluid chamber 223. For this reason, even when a frequency twice as high as the primary anti-resonance frequency of the hydraulic oil flow path is excited, the flow fluctuation of the hydraulic oil generated due to the resonance of the hydraulic oil flow path is stabilized. Can be deterred.

<Comparison by duty ratio d>
4 and 8 are compared, the energy recovery device 1 including the inertial fluid chamber 21 formed of a cylindrical member (straight pipe shape) extending linearly along the direction of the flow of the hydraulic oil. Thus, the recoverability of hydraulic oil when the duty ratio d is different can be examined. That is, when the duty ratio d = 0.5, a frequency component that is an odd multiple of the fundamental frequency (= switching frequency f) is excited, whereas when the duty ratio d = 0.75, the fundamental frequency An integer frequency component is excited. For this reason, when the inertial fluid chamber according to the present invention is linear, such as the inertial fluid chamber 21, and the cross-sectional shape is uniform, the duty of the pulses for controlling the low pressure side switch 3L and the high pressure side switch 3H By controlling the ratio to be close to d = 0.5, the secondary frequency component of the fundamental frequency of the flow rate fluctuation can be reduced. For this reason, the fluctuation | variation of the flow volume of the hydraulic oil which generate | occur | produces with the resonance of the flow path of hydraulic oil can be suppressed. As a result, when recovering the energy of the hydraulic oil, it is possible to prevent a decrease in the amount of recovered energy.

As described above, when the duty ratio is controlled to be close to d = 0.5, the control unit 5 desirably sets the duty ratio d in the range of 0.45 to 0.55. . In this case, it is possible to stably suppress fluctuations in the flow rate of the hydraulic fluid that occurs in association with the resonance of the hydraulic fluid passage including the inertia fluid chamber 21 and the switch passage.

Next, a third embodiment of the present invention will be described. In addition, in this embodiment, since it differs in the point provided with the inertial fluid chamber 23 instead of the inertial fluid chamber 21 compared with previous 1st Embodiment, it demonstrates centering on the said difference and is a common point The description of is omitted.

In the present embodiment, the energy recovery device 1 (FIG. 1) includes an inertial fluid chamber 23. FIG. 10 is a cross-sectional view of the inertial fluid chamber 23. Region (A) in FIG. 10 corresponds to a cross-sectional view of inertial fluid chamber 23 cut along the longitudinal direction (direction in which hydraulic oil flows), and region (B) represents inertial fluid chamber 23 in the radial direction (operational). This corresponds to a cross-sectional view taken along the direction in which the oil flows.

The inertial fluid chamber 23 has a cylindrical internal space communicating with the piston side chamber 203 of the hydraulic cylinder 20 (FIG. 1). The inertial fluid chamber 23 receives hydraulic oil discharged from the piston side chamber 203 as the piston 202 moves. As an example, in this embodiment, the inertial fluid chamber 23 has a pipe shape, and the inertial fluid chamber 23 has a circular cross-sectional shape. The volume of the internal space of the inertial fluid chamber 23 is smaller than the volume of the internal space of the hydraulic cylinder 20. The internal space of the inertial fluid chamber 23 is filled with hydraulic oil. The inertial fluid chamber 23 includes a fluid chamber inlet 230A, a fluid chamber outlet 230B, and a plurality of sub-fluid chambers (a third fluid chamber 231, a fourth fluid chamber 232, and a fifth fluid chamber 233) (a plurality of pipelines). . The fluid chamber inlet 230 A is an inlet of the inertial fluid chamber 23 and communicates with the piston-side chamber 203 of the hydraulic cylinder 20. The fluid chamber outlet 230B is an outlet of the inertial fluid chamber 23, and the low pressure pipe PL and the high pressure pipe PH (FIG. 1) are connected (communicated) in parallel.

As described above, the inertial fluid chamber 23 includes the third fluid chamber 231 on the most downstream side, the fourth fluid chamber 232, and the fifth fluid chamber 233 on the most upstream side. As shown in FIG. 10, the fifth fluid chamber 233, the fourth fluid chamber 232, and the third fluid chamber 231 are sequentially arranged from the fluid chamber inlet 230A to the fluid chamber outlet 230B, and the flow of hydraulic oil The cross-sectional area of each fluid chamber in the cross section orthogonal to the direction is set so as to gradually decrease along the flow direction of the hydraulic oil. Note that the cross-sectional areas of the third fluid chamber 231, the fourth fluid chamber 232, and the fifth fluid chamber 223 are constant. In this embodiment, the inertial fluid chamber 23 includes a three-stage pipeline, but as described later, the inertial fluid chamber 23 may include a four-stage or more pipeline.

Referring to FIG. 10, the total length of inertial fluid chamber 23 along the direction of hydraulic oil flow is defined as L (mm). In the present embodiment, the lengths of the third fluid chamber 231, the fourth fluid chamber 232, and the fifth fluid chamber 233 are set to L / 3, in other words, one third of L. The cross-sectional areas of the third fluid chamber 231, the fourth fluid chamber 232, and the fifth fluid chamber 233 are defined as A _P1 , A _P2 , and A _P3 , respectively (A _P1 <A _P2 <A _P3 ). In this case, it is desirable that the ratio of each cross-sectional area satisfies the following

expressions

2 and 3.
a ₂ = A _P2 / A _P1 <5 (Formula 2)
a ₃ = A _P3 / A _P1 <5 (Formula 3)

When the energy recovery apparatus 1 including the inertial fluid chamber 23 according to the present embodiment is applied to a high-pressure pipe such as a construction machine, the 1/2 inch pipe has an inner diameter φ16.1 (mm), and 1+ (1/4 ) Inch piping has an inner diameter of φ35.5 (mm). Therefore, when the relationship between the inner diameters is converted into the ratio of the cross-sectional area, 4.84 (= (35.5 / 16.1) ² ) is obtained. For this reason, in view of the mounting on construction machines and the like, from the viewpoint of the mountability and cost of the energy recovery device 1, the ratios a ₂ and a ₃ of the cross-sectional areas of the pipelines are as shown in

Formulas

2 and 3, respectively. It is desirable to set it to less than 5. It is more desirable that the relations 2 <a ₂ <2.5 and 4.5 <a ₃ are satisfied. Furthermore, as a result of intensive experiments and verifications by the present inventors, it is most preferable that a ₂ = 2.25 and a ₃ = 5 are set in the case of a three-stage configuration. The desirable setting values of a ₂ = 2.25 and a ₃ = 5 are applicable when the lengths of the inertial fluid chambers 23 are changed and the lengths of the three stages of pipes are the same.

11 and 12 show an example of the relationship between the frequency of the pressure fluctuation generated in the hydraulic oil flow path and the flow fluctuation of the hydraulic oil (frequency response of the flow fluctuation) in the energy recovery device 1 according to the present embodiment. And corresponds to FIG. 3 of the first embodiment. That is, in FIG. 1, an inertial fluid chamber 23 is arranged instead of the inertial fluid chamber 21, the opening of the high-pressure side switch 3H is fully opened (free end), and the opening of the low-pressure side switch 3L is fully closed ( In the state of the fixed end, a pressure fluctuation that fluctuates in a sine wave is forcibly applied to the high-pressure source HP. FIGS. 11 and 12 are waveforms showing the flow rate variation (frequency response) of the hydraulic oil in the vicinity of the fluid chamber outlet 230B of the inertial fluid chamber 23 in this case, and correspond to FIG. 3 of the first embodiment. In FIG. 11, the total length L of the inertial fluid chamber 23 is set to 3 m, and in FIG. 12, the total length L of the inertial fluid chamber 23 is set to 9 m. The ratio of the cross-sectional area of the inertial fluid chamber 23 is set to a ₂ = 2.25 and a ₃ = 5. The data in FIGS. 11 and 12 may be calculated by simulation as in FIG. 3, or may be measured by a flow meter provided experimentally near the fluid chamber outlet 230B.

Referring to FIG. 11 in the case where the total length L of the inertial fluid chamber 23 is set to 3 m, the flow rate variation of the hydraulic fluid is determined according to the frequency of the applied pressure variation from the vibration characteristics provided in the entire hydraulic fluid flow path. The size changes. Here, “1” shown in the graph of FIG. 11 is the anti-resonance primary frequency of the flow path (system), “2” is the resonance primary frequency, and “3” is the anti-resonance secondary frequency. Yes, “4” is the resonant secondary frequency, and “5” is the anti-resonant tertiary frequency (the same applies to FIG. 12). Thus, also in FIG. 11, the antiresonance frequency and the resonance frequency appear alternately. Then, as shown in FIG. 10, the sectional areas of the fifth fluid chamber 233, the fourth fluid chamber 232, and the third fluid chamber 231 are reduced stepwise along the direction of the hydraulic oil flow, 11 is set to a ₂ = 2.25 and a ₃ = 5, the anti-resonant secondary frequency in FIG. 11 is twice the anti-resonant primary frequency (133 Hz) (266 Hz), and the anti-resonant secondary frequency is The resonance tertiary frequency is three times (399 Hz) the anti-resonance primary frequency.

Similarly, also in FIG. 12 when the total length L of the inertial fluid chamber 23 is set to 9 m, the antiresonance secondary frequency is twice (90 Hz) the antiresonance primary frequency (45 Hz), and the antiresonance tertiary frequency is Is three times the anti-resonant primary frequency (135 Hz).

Further, in the group of FIG. 13, the switching frequency f of the high pressure side switch 3 H and the low pressure side switch 3 L in the inertial fluid chamber 23 having a total length of 3 m shown in FIG. = 133 Hz) is a graph showing the transition of each characteristic value. 13A to 13E correspond to FIGS. 3A to 3E of the first embodiment. In the group shown in FIG. 13, the aforementioned duty ratio d is set to 0.75.

As in this embodiment, the inertial fluid chamber 23 has a shape in which a plurality of sub-fluid chambers (pipes) are reduced in stages, so that the flow rate fluctuation of the hydraulic oil is reduced and the energy regeneration rate is improved. To do. In the inertial fluid chamber 21 according to the first embodiment, at the duty ratio d = 0.75, the switching frequency f of the high-pressure side switch 3H and the low-pressure side switch 3L is set to the anti-resonant primary frequency (frequency in FIG. 3). Each characteristic value when set to “1” = 88 Hz) is shown in FIG. Here, compared with the periodic reverse flow (portion where the flow rate is zero or less) generated in the flow rate near the inertial fluid chamber outlet in FIG. 8C, in FIG. The occurrence time of periodic backflow is reduced. As a result, the flow fluctuation of the hydraulic oil is reduced, and the energy of the hydraulic oil can be efficiently regenerated. In FIG. 8 group, since the frequency (secondary fundamental frequency) twice the switching frequency f of the high-voltage side switch 3H and the low-voltage side switch 3L is close to the resonance primary frequency of the system, The flow fluctuation of the frequency component is large (FIG. 8E). On the other hand, in the result shown in FIG. 13 group, the flow fluctuation of the secondary frequency component of the fundamental frequency is suppressed (FIG. 13E).

Similarly, in the group of FIG. 14, the switching frequency f of the high pressure side switch 3 H and the low pressure side switch 3 L is set to the anti-resonant primary frequency (frequency “1” in FIG. 12). It is a graph showing transition of each characteristic value when set to “= 45 Hz”. In the group in FIG. 14 as well, the aforementioned duty ratio d is set to 0.75. And in FIG. 14C, compared with FIG. 8C, the generation | occurrence | production time of the periodic backflow which has generate | occur | produced in the inertia fluid chamber exit vicinity passage flow rate has shrunk | reduced. As a result, even when the switching frequency f of the high-pressure side switch 3H and the low-pressure side switch 3L is set to a low frequency, the flow fluctuation of the hydraulic oil is reduced and the energy of the hydraulic oil can be efficiently regenerated. . In the results shown in FIG. 14 group as well, the flow fluctuation of the second-order fundamental frequency component is suppressed (FIG. 14E). In addition, in the results shown in FIG. 14 group, the switching frequency f can be set lower than that in FIG. 13 group. Accordingly, since the switching response performance required for the high-pressure side switch 3H and the low-pressure side switch 3L can be lowered, the energy regeneration of the hydraulic oil can be realized at a lower cost.

As described above, in this embodiment, the inertial fluid chamber 23 includes a plurality of sub fluid chambers from the fluid chamber inlet 230A toward the fluid chamber outlet 230B. These fluid chambers are connected so that the cross-sectional area is gradually reduced. Then, when the ratio of each cross-sectional area is set to a predetermined value and optimized so that the switching frequency f is set to the anti-resonant primary frequency of the hydraulic oil flow path, the flow fluctuation of the hydraulic oil is changed. Can be reduced. Thus, by setting the shape of the inertial fluid chamber 23, the frequency response curve can be changed as shown in FIG. 3, FIG. 11, and FIG. Then, by reducing the cross-sectional area of the inertial fluid chamber 23 in stages, the primary anti-resonance frequency of the system is increased compared to the straight pipe shape (straight), and the third-order anti-resonance frequency is increased. Decrease. On the other hand, the secondary antiresonance frequency does not change greatly. As a result, by optimizing the cross-sectional area of the inertial fluid chamber 23, the secondary and tertiary antiresonance frequencies approach an integral multiple (2 times, 3 times) of the primary antiresonance frequency.

Note that the shape of the inertial fluid chamber 23 is not limited to a three-stage configuration. The inertial fluid chamber 23 may have four or five or more stages. Also in this case, the cross-sectional area of the inertial fluid chamber 23 is reduced stepwise, and the ratio of the cross-sectional areas is set as described above, so that fluctuations in the flow rate of the hydraulic oil are reduced and a high energy regeneration rate is achieved. Secured. Further, in FIGS. 13 and 14 described above, the duty ratio is 0.75, but the same effect is exhibited under other conditions. In the inertial fluid chamber 23, the present invention is limited to the anti-resonant secondary frequency being twice the anti-resonant primary frequency and the anti-resonant tertiary frequency being three times the anti-resonant primary frequency. is not. Depending on the shape of the inertial fluid chamber 23, the antiresonance secondary frequency may be in the vicinity of twice the antiresonance primary frequency, and the antiresonance tertiary frequency may be in the vicinity of three times the antiresonance primary frequency. Further, at least the antiresonant secondary frequency may be in the vicinity of twice the antiresonant primary frequency. In this case, the neighborhood may be set in a range of ± 5% of the target frequency.

<Setting range of switching frequency f>
As described above, the switching frequency f of the low pressure side switch 3L and the high pressure side switch 3H controlled by the control unit 5 is set in the vicinity of the anti-resonance frequency of the flow path (system) through which the hydraulic oil (working fluid) flows. It is desirable. In this case, the antiresonance frequency is not limited to the first order, and may be a second order or third order (Nth order, N is a natural number) antiresonance frequency. As shown in FIG. 3, there is a region where the flow rate fluctuation increases as the order increases even at the anti-resonance frequency. For this reason, it is desirable that the switching frequency f be set in the vicinity of the primary anti-resonance frequency.

Here, in FIG. 3, the primary anti-resonance frequency (arrow “1”) is frn (Hz), the primary resonance frequency (arrow “2”) is frt (Hz), and the flow rate of hydraulic oil at each frequency When the fluctuations are Vfrn (L / min / (kgf / cm ² )) and Vfrt (L / min / (kgf / cm ² )), it is desirable that the set switching frequency f satisfies the following formula 4. .
f ≦ (frn + frt) / 2 (Formula 4)
In this case, the switching frequency f is set at a position closer to the primary anti-resonance frequency frn than at least the primary resonance frequency frt. Therefore, increase in flow rate fluctuation and backflow of hydraulic oil are suppressed. As a result, it is possible to stably suppress fluctuations in the flow rate of the hydraulic fluid that occurs in association with the resonance of the hydraulic fluid passage including the inertia fluid chamber 21 (inertial fluid chamber 22) and the switch passage.

Further, it is desirable that the set switching frequency f satisfies the following formula 5.
f ≧ frn / 2 (Formula 5)
In other words, the switching frequency f is desirably a frequency that is at least higher than half the frequency of the first-order antiresonance frequency frn. In this case, the switching frequency f is not too close to 0, and an increase in flow rate fluctuation is suppressed (FIG. 3). Therefore, it is possible to more stably suppress fluctuations in the flow rate of the hydraulic oil that occurs with the resonance of the flow path of the hydraulic oil.

Further, assuming that the flow rate fluctuation at the switching frequency f is Vf, it is desirable that Vf satisfies the following expression (6).
Vf ≦ (Vfrn + Vfrt) / 2 (Expression 6)
In this case, the flow rate fluctuation Vf at the switching frequency f is set in a region closer to the flow rate fluctuation Vfrn at the primary anti-resonance frequency frn than at least the flow rate fluctuation Vfrt at the primary resonance frequency frt. Therefore, increase in flow rate fluctuation and backflow of hydraulic oil are suppressed. As a result, it is possible to more stably suppress fluctuations in the flow rate of the hydraulic oil that occurs with the resonance of the flow path of the hydraulic oil. In this case as well, it is more desirable that the above Expression 5 is satisfied.

Furthermore, a more preferable setting range of the switching frequency f will be described. FIG. 15 is a graph group corresponding to FIG. 4C, and is a graph showing the time transition of the flow rate of the hydraulic oil in the vicinity of the fluid chamber outlet 210 of the inertial fluid chamber 21 in the energy recovery device 1 shown in FIG. 1. 15A, the switching frequency f is set to 72.5 Hz, the switching frequency f is set to 80 Hz in FIG. 15B, the switching frequency f is set to 88 Hz in FIG. 15C, the switching frequency f is set to 100 Hz in FIG. In FIG. 15E, the switching frequency f is set to 105 Hz, in FIG. 15F, the switching frequency f is set to 110 Hz, and in FIG. 15G, the switching frequency f is set to 125 Hz. In either case, the aforementioned duty ratio d = 0.5.

In FIG. 15A, the flow rate of the hydraulic oil in the vicinity of the fluid chamber outlet 210 of the inertial fluid chamber 21 is periodically negative, and a reverse flow is generated. In FIG. 15B, the flow rate of the hydraulic oil instantaneously becomes negative, but no back flow actually occurred. Further, in FIGS. 15C and 15D, the flow rate of the hydraulic oil in the vicinity of the fluid chamber outlet 210 of the inertial fluid chamber 21 is continuously positive, and the hydraulic oil is stably recovered by the high-pressure source HP. . Further, in FIG. 15E, as in FIG. 15B, although the flow rate of the hydraulic oil is instantaneously negative, no back flow actually occurred. 15F and 15G, similarly to FIG. 15A, the flow rate of the hydraulic oil in the vicinity of the fluid chamber outlet 210 of the inertial fluid chamber 21 is periodically negative, and a backflow is generated.

FIG. 16 is an enlarged graph around the anti-resonance frequency (primary) and the resonance frequency (primary) in the graph of FIG. From the results of FIG. 15A to FIG. 15G, when the switching frequency f is set in the range of 77.5 Hz to 100 Hz (the following expression 7), the backflow of hydraulic oil does not occur and stable energy recovery can be realized. It is said. That is, when the anti-resonance frequency (primary) of the flow path of the energy recovery device 1 is 88 Hz,
77.5 ≦ f ≦ 100 (Hz) (Expression 7)
It is desirable that this relationship is satisfied.
The inventors of the present invention changed the length of the inertial fluid chamber 21 of the energy recovery device 1 and the lengths of the low pressure side branch path 31 and the high pressure side branch path 32 at a plurality of levels, and evaluated the same as described above. As a result, it was confirmed that when the following formula 8 is satisfied, energy recovery in which backflow is similarly suppressed is realized.

If the anti-resonance frequency frn of the system is
0.88 × frn ≦ f ≦ 1.13 ≦ × frn (Formula 8)

<About energy recovery methods>
As described above, the energy recovery method according to the present invention is an energy recovery method for recovering the energy of hydraulic oil, which is a fluid chamber in which hydraulic oil is enclosed, and the volume of the fluid chamber is variable. Between the fluid chamber, the inertial fluid container communicating with the fluid chamber, the low-pressure side container and the high-pressure side container communicating in parallel with the inertial fluid container on the opposite side of the fluid chamber, and the inertial fluid container and the low-pressure side container Low pressure side switch for switching the flow of hydraulic oil, high pressure side switch for switching the flow of hydraulic oil between the high pressure side container and the inertial fluid container, the low pressure side switch and the high pressure side switch from the inertial fluid container And a switch passage for guiding the working fluid is prepared. Then, according to the reduction in the volume of the fluid chamber, the inertial fluid container at a switching frequency near the Nth-order (N is a natural number) anti-resonance frequency of the hydraulic fluid flow path including at least the inertial fluid container and the switch flow path. When the working fluid flows toward the low-pressure side container by controlling the high-pressure side switch and the low-pressure side switch so as to alternately switch the communication destination between the low-pressure side container and the high-pressure side container, The working fluid is caused to flow into the high-pressure side container by the inertial force generated in the container.

According to this method, the working fluid can be caused to flow into the high-pressure side container by the inertial force generated in the inertial fluid container when the working fluid flows from the inertial fluid container toward the low-pressure side container. Further, since the switching frequency for controlling the switching operation of the high-pressure side switch and the low-pressure side switch is set to a frequency in the vicinity of the Nth-order anti-resonance frequency of the flow path of the working fluid, the inertia fluid container and the switch flow It is possible to suppress fluctuations in the flow rate of the working fluid that occurs due to resonance of the flow path of the working fluid including the passage. For this reason, it becomes possible to suppress the fall of the energy recovery rate resulting from the flow volume fluctuation | variation of the working fluid in a flow path.

The energy recovery apparatus 1 and the energy recovery method according to each embodiment of the present invention have been described above. The present invention is not limited to these forms. The following modified embodiments are possible as the energy recovery device and the energy recovery method according to the present invention.

(1) In each of the above-described embodiments, the inertia fluid chamber 21, the inertia fluid chamber 22, and the inertia fluid chamber 23 have been described as having a circular cross section, but the present invention is not limited to this. The cross sections of the inertial fluid chamber 21, the inertial fluid chamber 22, and the inertial fluid chamber 23 may have shapes other than a circle.

(2) In the second embodiment described above, the inertial fluid chamber 22 includes the intermediate fluid chamber 223, so that the frequency twice the primary anti-resonance frequency of the hydraulic oil flow path can be reduced. Although the embodiment has been described in a manner deviating from the primary resonance frequency of the road, the present invention is not limited to this. Due to the shape of the inertia fluid chamber 22 having a curved pipe with a curved flow path, a frequency twice the primary anti-resonance frequency of the hydraulic oil flow path is the primary resonant frequency of the hydraulic oil flow path. The mode may be deviated or may be based on other shapes and structures.

Provided by the present invention is an energy recovery device that recovers the energy of a working fluid. The energy recovery apparatus includes a fluid chamber in which the working fluid is sealed, the fluid chamber having a variable volume, and a first internal space communicating with the fluid chamber. An inertia fluid container that receives the working fluid discharged from the fluid chamber as the size of the fluid chamber decreases, and a second internal space that is set at a lower pressure than the fluid chamber and communicates with the first internal space of the inertia fluid container. A low-pressure side container that receives the working fluid that has flowed out of the inertial fluid container, and a third internal space that is set at a higher pressure than the second internal space of the low-pressure side container and communicates with the first internal space of the inertial fluid container A high-pressure side container that receives the working fluid that has flowed out of the inertial fluid container, and a low-pressure side opening that allows the working fluid to flow between the inertial fluid container and the low-pressure side container A low-pressure side switch that operates to open and close the low-pressure side opening, and a high-pressure side opening that allows the working fluid to flow between the high-pressure side container and the inertial fluid container. A high-pressure side switch that operates to open and close the opening, a switch passage that is arranged from the inertial fluid container to the low-pressure side switch and the high-pressure side switch, and guides the working fluid; and the fluid Controls the opening / closing operation of the high-pressure side switch and the low-pressure side switch so that the communication destination of the inertial fluid container is alternately switched between the low-pressure side container and the high-pressure side container according to the reduction in the volume of the chamber And a switch controller that causes the working fluid to flow into the high-pressure side container by an inertial force generated in the first internal space of the inertial fluid container when the working fluid flows toward the low-pressure side container. . The switch controller controls a switching frequency for switching a communication destination of the inertial fluid container between the low-pressure side container and the high-pressure side container, and includes at least the inertial fluid container and the switch channel. It is set to a frequency in the vicinity of the Nth order (N is a natural number) anti-resonance frequency of the flow path.

According to this configuration, the switch controller controls the high-pressure side switch and the high-pressure side switch so that the communication destination of the inertial fluid container is alternately switched between the low-pressure side container and the high-pressure side container according to the reduction in the volume of the fluid chamber. Controls the opening / closing operation of the low-voltage side switch. As a result, when the working fluid flows from the inertial fluid container toward the low pressure side container, the working fluid can flow into the high pressure side container by the inertial force generated in the first internal space of the inertial fluid container. Furthermore, the switching frequency for controlling the switching operation of the high-pressure side switch and the low-pressure side switch is set to a frequency in the vicinity of the Nth-order anti-resonance frequency of the flow path of the working fluid. For this reason, the flow volume fluctuation | variation of the working fluid which generate | occur | produces with the resonance of the flow path of the working fluid containing an inertial fluid container and a switch flow path can be suppressed. As a result, it is possible to suppress a decrease in energy recovery rate caused by fluctuations in the flow rate of the working fluid in the flow path.

In the above-described configuration, it is preferable that the switch control unit sets the switching frequency to a frequency in the vicinity of a primary anti-resonance frequency of the flow path of the working fluid.

According to this configuration, it is possible to further suppress fluctuations in the flow rate of the working fluid that occurs in association with the resonance of the flow path of the working fluid including the inertial fluid container and the switch flow path.

In the above configuration, it is desirable that the frequency in the vicinity of the primary anti-resonance frequency is a frequency closer to the primary anti-resonance frequency than the primary resonance frequency of the flow path of the working fluid.

According to this configuration, it is possible to stably suppress fluctuations in the flow rate of the working fluid that occurs with the resonance of the flow path of the working fluid including the inertial fluid container and the switch flow path.

In the above configuration, it is desirable that the frequency in the vicinity of the primary anti-resonance frequency is a frequency that is at least larger than half the frequency of the primary anti-resonance frequency.

According to this configuration, it is possible to more stably suppress fluctuations in the flow rate of the working fluid that occurs due to resonance of the flow path of the working fluid including the inertial fluid container and the switch flow path.

In the above configuration, the frequency in the vicinity of the primary anti-resonance frequency is greater than the flow rate fluctuation of the working fluid generated in the flow path at the primary resonance frequency of the flow path of the working fluid. It is desirable that the frequency of the flow rate of the working fluid be close to the flow rate variation of the working fluid at the anti-resonance frequency.

In the above configuration, the inertial fluid container has a shape in which a frequency twice as high as a primary anti-resonance frequency of the flow path of the working fluid deviates from a primary resonance frequency of the flow path of the working fluid. It is desirable to have.

According to this configuration, even when a frequency twice as high as the primary anti-resonance frequency of the flow path of the working fluid is excited, the resonance of the flow path of the working fluid including the inertial fluid container and the switch flow path. Therefore, fluctuations in the flow rate of the working fluid that occur along with this can be suppressed.

In the above configuration, the inertial fluid container is a cylindrical member extending along the flow direction of the working fluid, and communicates with the first conduit and the first conduit that communicate with the fluid chamber. A second pipe having a larger inner diameter than the first pipe; and a third pipe having a smaller inner diameter than the second pipe and communicating with the second pipe and the switch passage. It is desirable.

According to this configuration, even when a frequency twice as high as the primary anti-resonance frequency of the flow path of the working fluid is excited, the resonance of the flow path of the working fluid including the inertial fluid container and the switch flow path. Therefore, fluctuations in the flow rate of the working fluid that occur along with this can be stably suppressed.

In the above configuration, the inertial fluid container is a cylindrical member extending linearly along the flow direction of the working fluid, and the switch controller controls the communication destination of the inertial fluid container with the low pressure It is desirable to set the duty ratio for switching between the side container and the high-pressure side container to be close to 0.5.

According to this configuration, it is possible to suppress fluctuations in the flow rate of the working fluid that occurs in association with the resonance of the flow path of the working fluid including the inertial fluid container and the switch flow path.

In the above configuration, it is preferable that the switch control unit sets the duty ratio in a range of 0.45 to 0.55.

In the above configuration, in the inertial fluid container, the secondary anti-resonance frequency of the flow path of the working fluid is in the vicinity of twice the primary anti-resonance frequency of the flow path of the working fluid. It may be provided with such a shape.

In the above configuration, the inertial fluid container has a third-order anti-resonance frequency of the flow path of the working fluid in the vicinity of a frequency that is three times the primary anti-resonance frequency of the flow path of the working fluid. It may be provided with such a shape.

In the above configuration, the inertial fluid container is a cylindrical member extending along the flow direction of the working fluid, and the inertial fluid container includes a container inlet communicating with the fluid chamber, and the switch flow. A plurality of conduits in a cross section orthogonal to the direction of the flow of the working fluid, the container outlet communicating with the passage, and a plurality of conduits sequentially disposed from the container inlet to the container outlet The cross-sectional area may be set so as to gradually decrease along the flow direction of the working fluid.

According to this configuration, it is possible to stably suppress fluctuations in the flow rate of the working fluid that occurs due to the resonance of the flow path of the working fluid including the inertial fluid container and the switch flow path.

Claims

An energy recovery device for recovering the energy of a working fluid,
A fluid chamber in which the working fluid is enclosed, wherein the volume of the fluid chamber is variable;
An inertial fluid container having a first internal space communicating with the fluid chamber and receiving the working fluid discharged from the fluid chamber as the volume of the fluid chamber decreases.
A low-pressure side container that includes a second internal space that is set at a lower pressure than the fluid chamber and communicates with the first internal space of the inertial fluid container, and that receives the working fluid flowing out of the inertial fluid container;
A high pressure side that has a third internal space that is set at a higher pressure than the second internal space of the low pressure side container and communicates with the first internal space of the inertial fluid container, and that receives the working fluid that has flowed out of the inertial fluid container A container,
A low-pressure side switch that operates to open and close the low-pressure side opening by forming a low-pressure side opening that allows the working fluid to flow between the inertial fluid container and the low-pressure side container;
Forming a high-pressure side opening that allows the working fluid to flow between the high-pressure side container and the inertial fluid container, and a high-pressure side switch that operates to open and close the high-pressure side opening;
A switch passage that is arranged from the inertial fluid container to the low-pressure side switch and the high-pressure side switch, and leads the working fluid;
Opening and closing of the high-pressure side switch and the low-pressure side switch so that the communication destination of the inertial fluid container is alternately switched between the low-pressure side container and the high-pressure side container in accordance with a reduction in the volume of the fluid chamber. By controlling the operation, when the working fluid flows toward the low pressure side container, the opening and closing of the working fluid to flow into the high pressure side container by the inertial force generated in the first internal space of the inertial fluid container A device controller;
With
The switch controller controls a switching frequency for switching a communication destination of the inertial fluid container between the low-pressure side container and the high-pressure side container, and includes at least the inertial fluid container and the switch channel. An energy recovery device that is set to a frequency in the vicinity of the Nth-order (N is a natural number) anti-resonance frequency of the flow path.
The energy recovery device according to claim 1, wherein the switch control unit sets the switching frequency to a frequency in the vicinity of a primary anti-resonance frequency of the flow path of the working fluid.
The energy recovery according to claim 2, wherein the frequency in the vicinity of the primary anti-resonance frequency is a frequency closer to the primary anti-resonance frequency than the primary resonance frequency of the flow path of the working fluid. apparatus.
4. The energy recovery apparatus according to claim 3, wherein the frequency in the vicinity of the primary anti-resonance frequency is a frequency that is at least higher than half the frequency of the primary anti-resonance frequency.
The frequency in the vicinity of the primary anti-resonance frequency is higher than the primary anti-resonance frequency than the flow fluctuation of the working fluid generated in the flow path at the primary resonance frequency of the flow path of the working fluid. The energy recovery device according to claim 2, wherein the energy recovery device has a frequency at which the flow rate fluctuation of the working fluid close to the flow rate fluctuation of the working fluid generated in the flow path is generated in the flow path.
The inertial fluid container has a shape such that a frequency twice as high as a primary antiresonance frequency of the flow path of the working fluid deviates from a primary resonance frequency of the flow path of the working fluid. The energy recovery device according to claim 1.
The inertial fluid container is a cylindrical member extending along the direction of flow of the working fluid, the first conduit communicating with the fluid chamber, and the first conduit communicating with the first conduit. A second pipe line having a larger inner diameter, and a third pipe line communicating with the second pipe line and the switch channel and having a smaller inner diameter than the second pipe line. The energy recovery device described.
The inertial fluid container is a cylindrical member extending linearly along the direction of the flow of the working fluid,
The energy recovery device according to claim 1, wherein the switch control unit sets a duty ratio for switching a communication destination of the inertial fluid container between the low-pressure side container and the high-pressure side container in the vicinity of 0.5.
The energy recovery device according to claim 8, wherein the switch control unit sets the duty ratio in a range of 0.45 to 0.55.
The inertial fluid container has a shape such that the secondary antiresonance frequency of the flow path of the working fluid is in the vicinity of twice the primary antiresonance frequency of the flow path of the working fluid. The energy recovery device according to claim 2.
The inertial fluid container has a shape such that a third-order anti-resonance frequency of the flow path of the working fluid is in the vicinity of a frequency that is three times the primary anti-resonance frequency of the flow path of the working fluid. The energy recovery device according to claim 10.
The inertial fluid container is a cylindrical member extending along the flow direction of the working fluid, and the inertial fluid container is a container inlet communicating with the fluid chamber and a container communicating with the switch channel. An outlet and a plurality of pipes arranged in order from the container inlet to the container outlet, and a cross-sectional area of the plurality of pipes in a cross section orthogonal to the direction of the flow of the working fluid is The energy recovery device according to claim 10 or 11, wherein the energy recovery device is set so as to be reduced stepwise along the direction of flow of the working fluid.
An energy recovery method for recovering the energy of a working fluid,
A fluid chamber in which the working fluid is sealed, wherein the volume of the fluid chamber is variable; an inertial fluid container communicating with the fluid chamber; and the inertial fluid on a side opposite to the fluid chamber A low-pressure side container and a high-pressure side container communicating in parallel with the container, a low-pressure side switch for switching the flow of the working fluid between the inertial fluid container and the low-pressure side container, the high-pressure side container and the inertia A high-pressure switch that switches the flow of the working fluid to and from the fluid container, and a switch that leads from the inertial fluid container to the low-pressure switch and the high-pressure switch to guide the working fluid And a flow path,
In response to a reduction in the volume of the fluid chamber, at least a switching frequency in the vicinity of the Nth-order (N is a natural number) anti-resonance frequency of the working fluid flow path including the inertial fluid container and the switch flow path, By controlling the high-pressure side switch and the low-pressure side switch so that the communication destination of the inertial fluid container is alternately switched between the low-pressure side container and the high-pressure side container, the working fluid is supplied to the low-pressure side container. An energy recovery method in which the working fluid is caused to flow into the high-pressure side container by an inertial force generated in the inertial fluid container when flowing toward the high pressure side.