JP7304205B2 - fluid pressure device - Google Patents

Description

The present invention relates to fluid pressure devices.

In Patent Document 1, a motor pump that supplies oil from an oil tank to a hydraulic circuit, first and second solenoid valves connected in series, and a rod at a connection point with the oil inflow side of the first solenoid valve A double-acting cylinder connected to the cylinder on the side that discharges oil, and the cylinder on the side that stores the rod is connected to the side of the second solenoid valve that flows in oil, and the cylinder of the double-acting cylinder and the first and second A hydraulic control circuit for a double-acting cylinder is disclosed that includes a proportional solenoid valve provided at a connection with the solenoid valve.

JP 2011-214598 A

In the hydraulic circuit disclosed in Patent Document 1, a relief valve is provided in a relief passage branching from a discharge passage that guides hydraulic oil discharged from a motor pump. For example, even when a sudden pressure rise occurs in the discharge passage, such as when the cylinder is operated to the stroke end, the relief valve opens to suppress the sudden pressure rise in the discharge passage. As a result, overloads on the pump and cylinders are suppressed.

On the other hand, in the hydraulic circuit described above, the proportional solenoid valve is operated to control the flow rate of hydraulic oil supplied to the double-acting cylinder, thereby slowing down the speed at which the rod of the double-acting cylinder starts and stops. . When the opening degree of the proportional solenoid valve is reduced to limit the flow rate of hydraulic oil supplied to the double-acting cylinder, the discharge pressure of the motor pump located upstream of the proportional control valve increases. However, even if the discharge pressure of the motor pump increases in this way, the relief valve will not open if the discharge pressure is less than the relief pressure of the relief valve. That is, even if the opening degree of the proportional solenoid valve is controlled to be small and the discharge pressure of the pump increases, the relief valve does not operate quickly, and the discharge pressure of the motor pump increases until it reaches the relief pressure. In this case, the load on the motor pump increases, and the power consumption also increases accordingly.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object thereof is to save energy in a fluid pressure device.

The present invention relates to a fluid pressure device comprising a proportional electromagnetic valve for controlling the flow rate of working fluid supplied from a pump to a fluid pressure actuator, and a discharge passage for guiding the working fluid discharged from the pump and provided with the proportional electromagnetic valve. a relief passage that branches from the discharge passage upstream of the proportional solenoid valve and communicates with the tank; and a relief mechanism that opens and closes the relief passage. When the set differential pressure is reached, the relief passage is opened, and when the pressure on the downstream side of the proportional solenoid valve in the discharge passage reaches the predetermined set pressure, the relief passage is opened and the differential pressure across the proportional solenoid valve reaches the set differential pressure. Then, even if the pressure on the downstream side of the proportional electromagnetic valve in the discharge passage is less than the set pressure, the relief passage is opened, and the set pressure is higher than the set differential pressure.

In this invention, the speed of the fluid pressure actuator is controlled by controlling the flow rate of the working fluid supplied to the fluid pressure actuator by the proportional solenoid valve. When the differential pressure across the proportional solenoid valve reaches the set differential pressure of the relief mechanism, the relief passage is opened and part of the working fluid discharged from the pump is discharged to the tank. In this way, since the relief mechanism operates according to the differential pressure across the proportional solenoid valve, even if the discharge pressure of the pump rises due to the flow rate control by the proportional solenoid valve, the relief mechanism quickly operates and the pump is discharged. Therefore, the load on the pump can be suppressed. Therefore, the load on the electric motor that drives the pump can be reduced. Therefore, power consumption in the fluid pressure device can be suppressed. Further, when the pressure in the discharge passage on the downstream side of the proportional electromagnetic valve reaches the set pressure, the relief passage is opened by the relief mechanism and part of the working fluid discharged from the pump is discharged to the tank. As a result, it is possible to prevent the pump from being overloaded due to a sudden increase in the discharge pressure of the pump. Further, when the differential pressure across the proportional solenoid valve reaches the set differential pressure, even if the pressure on the downstream side of the proportional solenoid valve in the discharge passage is less than the set pressure, the relief passage is opened and the working fluid is discharged from the pump. part of is discharged into the tank. Since the working fluid discharged from the pump can be discharged before the pressure on the downstream side of the proportional solenoid valve in the discharge passage reaches the set pressure, an increase in discharge pressure of the pump can be suppressed when the fluid pressure actuator operates at low speed. Therefore, power consumption can be further suppressed while suppressing overloads on the pump and the electric motor.

In addition, the relief mechanism includes a relief valve provided in a relief passage, a pilot passage for guiding the pressure on the downstream side of the proportional solenoid valve to the relief valve as a pilot pressure exerting an urging force to close the relief passage, and a throttle portion that is provided in the pilot passage and applies resistance to the flow of the working fluid that passes through the pilot passage.

In this invention, even if an external force acts unintentionally during operation of the fluid pressure actuator, the resistance applied by the restrictor suppresses fluctuations in the pressure introduced to the relief valve through the pilot passage. As a result, it is possible to prevent the relief valve from operating unintentionally.

In addition, the relief mechanism includes a relief valve provided in a relief passage, a pilot passage for guiding the pressure on the downstream side of the proportional solenoid valve to the relief valve as a pilot pressure exerting an urging force to close the relief passage, A drain passage that branches from the pilot passage and communicates with the tank, a drain passage that branches from the pilot passage and communicates with the tank, and a check valve provided in the drain passage that allows only the flow of working fluid from the pilot passage to the tank. , wherein the set pressure is a cracking pressure at which the check valve opens, and the set differential pressure is a relief pressure at which the relief valve opens.

In the present invention, a check valve having a cracking pressure, which is a set pressure, is provided in a drain passage that branches off from the pilot passage and communicates with the tank. As a result, the relief mechanism functions as a safety valve that opens at the set pressure, so there is no need to provide a separate safety valve. Furthermore, since a passage for providing a safety valve is not required, the passage configuration in the fluid pressure device can be simplified. Therefore, the fluid pressure device can be made more compact.

According to the present invention, it is possible to save energy in the fluid pressure device.

BRIEF DESCRIPTION OF THE DRAWINGS It is a perspective view which shows a truck vehicle provided with the wing opening/closing apparatus which concerns on embodiment of this invention. 1 is a hydraulic circuit diagram of a wing opening/closing device according to an embodiment of the present invention; FIG. It is a graph chart which shows the relationship of the energization amount and time to the proportional electromagnetic valve of the wing opening/closing apparatus which concerns on embodiment of this invention. It is a hydraulic circuit diagram of a wing opening and closing device according to a comparative example of the embodiment of the present invention.

Hereinafter, fluid pressure devices according to embodiments of the present invention will be described with reference to the drawings. In the following description, the fluid pressure device is a wing opening/closing device 100 that is mounted on a truck 1 having a pair of left and right wings 2 and 3 that cover the luggage compartment 4 and that drives the wings 2 and 3.

First, with reference to Drawing 1 and Drawing 2, the whole wing closing device 100 composition concerning an embodiment is explained.

As shown in FIG. 1, the pair of wings 2 and 3 are rotatably connected to the luggage compartment 4 via pivot shafts 5 provided in the upper part of the luggage compartment 4, respectively.

The left and right wings 2 and 3 are independently opened and closed vertically by a wing opening/closing device 100 when an operation switch (not shown) provided on the truck 1 is operated by an operator. The left and right wings 2 and 3 are never opened and closed at the same time, and are constructed so that when one of the wings is driven, the other wing is not driven. In the following, the opening and closing of the left wing 2 will be mainly described, and the illustration and detailed description of the opening and closing of the right wing 3 will be omitted as appropriate because they have the same configuration.

The wing opening/closing device 100 includes, as shown in FIG. Hydraulic cylinders 20 as a pair of fluid pressure actuators for opening and closing the wings 2 by expanding and contracting with hydraulic oil as a fluid, and a fluid pressure control device 30 for controlling the flow of hydraulic oil supplied to and discharged from the pair of hydraulic cylinders 20. , and a controller 70 for controlling the hydraulic control device 30 .

The electric motor 10 is, for example, a three-phase brassless motor, and is driven by power supply. In this embodiment, the electric motor 10 rotates at a constant speed.

The pump 11 is rotationally driven by the electric motor 10 and pressurizes and discharges hydraulic oil through a discharge passage 13 . A gear pump, for example, is used as the pump 11 . The discharge passage 13 branches into two and guides hydraulic oil to a pair of hydraulic cylinders 20 respectively.

A pair of hydraulic cylinders 20 are provided at the front and rear in the luggage compartment 4 (see FIG. 1). When the pair of hydraulic cylinders 20 synchronously extend and retract, the wing 2 rotates around the rotation shaft 5 and is opened and closed vertically.

Here, the pair of hydraulic cylinders 20 have the same configuration. In addition, in the fluid pressure control device 30, there is provided a configuration between the branch portion of the discharge passage 13 and the hydraulic cylinder 20 to control the operation of the hydraulic cylinder 20 (hereinafter referred to as "control section C1" and "control section C2", respectively). (see FIG. 2) also have the same configuration. Therefore, only the one hydraulic cylinder 20 and the control unit C1 for controlling the operation thereof will be described in detail below. Regarding the other hydraulic cylinder 20, the same reference numerals are assigned to the corresponding structures, and the description thereof is omitted. Further, detailed illustration and description of the other control unit C2 are omitted.

The hydraulic cylinder 20 includes a cylindrical cylinder tube 21, a piston rod 22 inserted into the cylinder tube 21, and a piston 23 provided at the end of the piston rod 22 and sliding along the inner peripheral surface of the cylinder tube 21. , provided.

The inside of the cylinder tube 21 is partitioned into a rod side chamber 24 and a bottom side chamber 25 by a piston 23 . The rod-side chamber 24 and the bottom-side chamber 25 are filled with hydraulic oil.

The fluid pressure control device 30 includes a control valve 40 that controls the operation of the hydraulic cylinder 20 by controlling the flow of hydraulic fluid supplied from the pump 11 to the hydraulic cylinder 20, and the hydraulic fluid supplied from the pump 11 to the hydraulic cylinder 20. and a proportional solenoid valve 50 that controls the flow rate of the The operation of the control valve 40 and the proportional solenoid valve 50 is controlled by the controller 70 .

A control valve 40 is provided in the branched discharge passage 13 . The control valve 40 is a 4-port 3-position electromagnetic switching valve whose positions are switched by the excitation of solenoids 41a and 41b. One port of the control valve 40 is connected to the discharge passage 13 communicating with the pump 11 and the discharge passage 16 communicating with the tank 12 . A rod side passage 14 communicating with the rod side chamber 24 of the hydraulic cylinder 20 and a bottom side passage 15 communicating with the bottom side chamber 25 of the hydraulic cylinder 20 are connected to the port on the other side of the switching valve.

The control valve 40 switches between communication and blocking of the rod side passage 14 and the bottom side passage 15 with respect to the discharge passage 13 and the discharge passage 16 by switching each position. Specifically, the control valve 40 connects the discharge passage 13 and the bottom-side passage 15 and the discharge passage 16 and the rod-side passage 14 to a raised position 40A, and the discharge passage 13 and the rod-side passage 14. It has a lowered position 40B that communicates with the discharge passage 16 and the bottom side passage 15, and a neutral position 40C that communicates both the rod passage and the bottom side passage 15 with the discharge passage 16. The control valve 40 is brought to a neutral position 40C by a pair of return springs 42a and 42b when the solenoids 41a and 41b are deenergized.

The rod-side passage 14 is provided with an operate check valve 31 that allows only the flow of hydraulic oil supplied to the rod-side chamber 24 . The bottom-side passage 15 is provided with a counterbalance valve 35 for preventing sudden drop due to the weight of the wing 2 (load). The operate check valve 31 opens when the pressure of hydraulic fluid in the rod-side passage 14 on the upstream side of the counterbalance valve 35 is guided as pilot pressure, and allows the hydraulic fluid discharged from the rod-side chamber 24 to flow. The counterbalance valve 35 opens when the pressure on the upstream side of the operate check valve 31 is introduced as the external pilot pressure, and allows the flow of hydraulic oil discharged from the bottom side chamber 25 . Since the operate check valve 31 and the counterbalance valve 35 can employ known configurations, a more specific description thereof will be omitted.

The proportional electromagnetic valve 50 is provided in the discharge passage 13 on the upstream side (pump 11 side) of the branched portion of the discharge passage 13 . The proportional solenoid valve 50 is switched from a blocking position 50A that blocks the discharge passage 13 to an opening position 50B that opens the discharge passage 13 as the amount of electricity supplied to the solenoid 51 increases. More specifically, in the proportional electromagnetic valve 50, the valve body (not shown) moves to a position where the electromagnetic force generated by the energization of the solenoid 51 and the spring force of the spring 52 as the biasing member are balanced. The valve is opened to the open position 50B with an opening area (opening degree) corresponding to the position of . The proportional solenoid valve 50 controls the flow rate of hydraulic oil passing through it by changing the opening area according to the amount of electricity supplied to the solenoid 51 . The proportional solenoid valve 50 is of a normally closed type and is in a shutoff position 50A that shuts off the discharge passage 13 by the biasing force of the spring 52 when the solenoid 51 is deenergized. The opening of the proportional solenoid valve 50 increases as the amount of power supplied to the solenoid 51 increases. The differential pressure across 50 becomes smaller.

The controller 70 is composed of a microcomputer having a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and an I/O interface (input/output interface). The RAM stores data in CPU processing, the ROM stores CPU control programs and the like in advance, and the I/O interface is used to input/output information with connected devices. The controller 70 may be composed of a plurality of microcomputers. The controller 70 is programmed so as to be able to execute at least the processing required for control according to each embodiment and modifications. Note that the controller 70 may be configured as one device, or may be divided into a plurality of devices so that each control in the present embodiment is distributed and processed by the plurality of devices.

The controller 70 controls the operation of the control valve 40 , the proportional electromagnetic valve 50 and the electric motor 10 according to the operation input by the operator through the operation switch provided on the truck 1 .

The wing opening/closing device 100 opens and closes the relief passage 17 that branches from the discharge passage 13 between the proportional solenoid valve 50 and the pump 11 (in other words, the upstream side of the proportional solenoid valve 50) and communicates with the tank 12, and the relief passage 17. and a relief mechanism 60 .

The relief mechanism 60 opens the relief passage 17 with two stages of working pressure (a set pressure and a set differential pressure, which will be described later), and discharges part of the working oil in the discharge passage 13 to the tank 12 .

The relief mechanism 60 includes a relief valve 61 provided in the relief passage 17 , a pilot passage 62 that guides the pressure on the downstream side of the proportional solenoid valve 50 as a pilot pressure to the relief valve 61 , and a pilot passage 62 that branches off and communicates with the tank 12 . and a check valve 64 that is provided in the drain passage 63 and allows hydraulic oil to flow from the pilot passage 62 to the tank 12 .

In the pilot passage 62, on the upstream side of the branch point where the drain passage 63 branches (between the branch point for the discharge passage 13 and the branch point where the drain passage 63 branches), resistance is imparted to the flow of hydraulic oil passing through the pilot passage 62. A diaphragm 66 is provided as a diaphragm. A throttle 67 is provided upstream of the check valve 64 in the drain passage 63 (between the branch point of the drain passage 63 with respect to the pilot passage 62 and the check valve 64). Rapid pressure fluctuations in the pilot passage 62 and the drain passage 63 are suppressed by the throttles 66 and 67 .

The relief valve 61 has a relief spring 61a as a biasing member that biases a valve body (not shown) in the valve closing direction. A relief pressure (set differential pressure) at which the relief valve 61 opens is set by the biasing force of the relief spring 61a. The discharge pressure of the pump 11 guided from the discharge passage 13 through the relief passage 17 is guided to the relief valve 61 as an internal pilot. The valve body is urged in the valve opening direction by the discharge pressure of the pump 11 . Further, the valve body is urged in the valve closing direction by pressure on the downstream side of the proportional electromagnetic valve 50 guided through the pilot passage 62 . Therefore, the relief valve 61 opens when the differential pressure between the upstream and downstream pressures of the proportional solenoid valve 50, which is the discharge pressure of the pump 11, exceeds the set differential pressure. By opening the relief valve 61 , part of the hydraulic oil discharged from the pump 11 is discharged from the relief passage 17 to the tank 12 .

The check valve 64 has a check spring 65 that biases a valve element (not shown) in the valve closing direction. The check spring 65 is configured to have a variable biasing force, and the cracking pressure (set pressure) of the check valve 64 is adjusted by adjusting the biasing force of the check spring 65 . The check valve 64 opens when the pressure on the downstream side of the proportional solenoid valve 50 guided through the throttle 66 reaches the cracking pressure, and discharges the hydraulic oil in the pilot passage 62 to the tank 12 .

Next, operation of the wing opening/closing device 100 will be described.

When a worker presses a start switch (not shown) while the truck 1 is stopped, the controller 70 supplies current to the electric motor 10 to drive the electric motor 10 at a predetermined rotational speed.

When an operator inputs an operation to open the wing 2, the controller 70 energizes one solenoid 41a of the control valve 40 and the solenoid 51 of the proportional electromagnetic valve 50, respectively. Therefore, the control valve 40 is switched to the raise position 40A. The proportional solenoid valve 50 opens the discharge passage 13 with an opening degree corresponding to the amount of electricity supplied to the solenoid 51 . The control of the proportional solenoid valve 50 will be explained later in detail.

When the discharge passage 13 is opened by the proportional electromagnetic valve 50 and the control valve 40 is switched to the rising position 40A, the working oil discharged from the pump 11 is guided to the bottom side passage 15 through the discharge passage 13 . The hydraulic oil guided to the bottom side passage 15 opens the counterbalance valve 35 and is supplied to the bottom side chamber 25 of the hydraulic cylinder 20 . Further, when hydraulic fluid is introduced to the bottom side passage 15 , the operate check valve 31 of the rod side chamber 24 is opened to allow the flow of hydraulic fluid discharged from the rod side chamber 24 of the hydraulic cylinder 20 to the tank 12 . Therefore, the hydraulic cylinder 20 is extended and the wing 2 is opened.

When an operator inputs an operation to close the wing 2, the controller 70 energizes the other solenoid 41b of the control valve 40 and the solenoid 51 of the proportional solenoid valve 50, respectively. Therefore, the control valve 40 is switched to the lowered position 40B, and the proportional electromagnetic valve 50 opens the discharge passage 13 at an opening degree corresponding to the amount of power supplied to the solenoid 51. As shown in FIG.

When the discharge passage 13 is opened by the proportional solenoid valve 50 and the control valve 40 is switched to the lowered position 40B, the working oil discharged from the pump 11 is guided to the rod side passage 14 through the discharge passage 13 . The hydraulic oil guided to the rod-side passage 14 opens the operate check valve 31 and is supplied to the rod-side chamber 24 of the hydraulic cylinder 20 . Further, when hydraulic fluid is introduced to the rod-side passage 14 , the counterbalance valve 35 of the rod-side chamber 24 is opened to allow hydraulic fluid to flow from the bottom-side chamber 25 of the hydraulic cylinder 20 to the tank 12 . Therefore, the hydraulic cylinder 20 is contracted and the wing 2 is closed.

Next, control of the energization amount of the proportional electromagnetic valve 50 by the controller 70 will be described.

As shown in FIG. 3, the controller 70 controls the energization rate of the proportional solenoid valve 50 from the detection of the operation input for opening or closing the wing 2 (T=0) until a predetermined time T1 elapses. The initial energization amount (zero in this embodiment) is gradually increased. As a result, the degree of opening of the proportional solenoid valve 50 gradually increases over time, and the flow rate of hydraulic oil supplied to the hydraulic cylinder 20 increases as the degree of opening of the proportional solenoid valve 50 increases. Therefore, the hydraulic cylinder 20 expands and contracts so that the speed gradually increases until the predetermined time T1 has passed since the operation input was detected (acceleration step). As a result, the opening operation and closing operation of the wing 2 are started at a low speed.

When the predetermined time T1 has elapsed since the operation input was detected and the amount of power supplied to the proportional solenoid valve 50 reaches the predetermined value A1, the controller 70 maintains the amount of power supplied to the proportional solenoid valve 50 at the predetermined value A1. As a result, the hydraulic cylinder 20 expands and contracts at a constant speed according to the energization amount A1 (constant speed step).

When the wing 2 moves close to being fully opened or fully closed, the controller 70 gradually decreases the energization rate to the proportional solenoid valve 50 over time until the wing 2 is fully closed or fully opened. As a result, the degree of opening of the proportional solenoid valve 50 gradually decreases, and the flow rate of hydraulic oil supplied to the hydraulic cylinder 20 also decreases as the degree of opening of the proportional solenoid valve 50 decreases. Therefore, the hydraulic cylinder 20 expands and contracts so that the speed gradually decreases (deceleration process). As a result, the opening operation and closing operation of the wing 2 are stopped at a low speed.

The movement of the wing 2 to the vicinity of the fully opened or fully closed state is detected by a detection sensor (not shown) attached to the luggage compartment 4 of the truck 1, for example. When the detection signal of the detection sensor is input to the controller 70, the controller 70 starts the deceleration process.

Further, even if the operator releases the operation switch during the opening/closing operation and the operation input is interrupted, the controller 70 gradually reduces the amount of power supplied to the proportional solenoid valve 50 with the lapse of time. As a result, even when stopping at an intermediate position between the fully open state and the fully closed state, the wing 2 can be decelerated and stopped.

Thus, in the wing opening/closing device 100, the hydraulic cylinder 20 is operated at a low speed when the opening/closing operation of the wing 2 is started and stopped. Thereby, the impact when the wing 2 starts moving and when it stops can be reduced.

In this embodiment, as shown in FIG. 3, the amount of energization to the proportional solenoid valve 50 increases proportionally (linearly) with the passage of time when the opening/closing operation is started, and increases proportionally with the passage of time when the opening/closing operation is stopped. decrease exponentially. It should be noted that the rate of increase/decrease of the amount of energization to the proportional solenoid valve 50 is not limited to this, as long as it changes monotonically with the passage of time. For example, the rate of change in the amount of energization with respect to time may be non-linear, such as exponentially changing.

Next, operation of the relief mechanism 60 will be described.

The relief mechanism 60 is designed so that the pressure in the discharge passage 13 does not rise suddenly and exceed the allowable pressure of seal members (not shown) used in each configuration of the pump 11, the hydraulic cylinder 20, and the wing opening/closing device 100. In addition, it suppresses an excessive increase in the discharge pressure of the pump 11 when the flow rate of hydraulic oil supplied to the hydraulic cylinder 20 is restricted by the proportional electromagnetic valve 50 . The sealing member is used in the pump 11, the hydraulic cylinder 20, the control valve 40, the proportional electromagnetic valve 50, and the like, and serves to prevent leakage of hydraulic oil in each configuration.

First, the function of suppressing an increase in the discharge pressure of the pump 11 when the proportional solenoid valve 50 controls the flow rate will be described.

The smaller the degree of opening of the proportional solenoid valve 50, the greater the pressure loss that occurs in the hydraulic oil passing through it. . In other words, in a state where the proportional solenoid valve 50 is in the shutoff position 50A (opening is zero), or in a state where the opening of the proportional solenoid valve 50 is controlled to be relatively low, such as when the opening/closing operation of the wing 2 is started or stopped, The discharge pressure of the pump 11 increases, and the differential pressure across the proportional solenoid valve 50 increases.

When the differential pressure across the proportional electromagnetic valve 50 becomes greater than the set differential pressure (the relief pressure of the relief valve 61), the relief valve 61 opens. As a result, part of the hydraulic fluid in the discharge passage 13 is discharged to the tank 12 through the relief passage 17, and the differential pressure across the proportional electromagnetic valve 50 is kept below the set differential pressure. That is, the discharge pressure of the pump 11 is kept below a predetermined pressure that causes the set differential pressure.

As the opening degree of the proportional solenoid valve 50 increases, the pressure loss occurring in the proportional solenoid valve 50 decreases, and the differential pressure across the proportional solenoid valve 50 decreases. When the differential pressure across the proportional solenoid valve 50 falls below the set differential pressure of the relief valve 61, the relief valve 61 closes.

Thus, in the wing opening/closing device 100, in the flow rate control by the proportional electromagnetic valve 50, it is possible to suppress the discharge pressure of the pump 11 from rising above the pressure that causes the set differential pressure.

Next, the function of limiting the pressure of the discharge passage 13 so as not to exceed the allowable pressure of the pump 11 etc. will be described.

In the wing opening/closing device 100, when the piston rod 22 reaches the stroke end in the contraction direction and the hydraulic cylinder 20 is in the most contracted state, the wings 2 are fully closed. Further, when the piston rod 22 reaches the stroke end in the extension direction and the hydraulic cylinder 20 reaches the maximum extension state, the wing 2 is fully opened. When the piston rod 22 of the hydraulic cylinder 20 moves to the stroke end in the extension direction or contraction direction, the pressure in the discharge passage 13 rises sharply. Along with this, the pressure of the hydraulic oil guided to the pilot passage 62 also increases.

When the pressure in the pilot passage 62 reaches the cracking pressure of the check valve 64 of the relief mechanism 60, the check valve 64 opens. By opening the check valve 64, the pressure on the downstream side of the proportional solenoid valve 50 that acts on the relief valve 61 as pilot pressure is discharged to the tank 12, and the pressure on the downstream side of the proportional solenoid valve 50 decreases. As a result, the differential pressure across the proportional solenoid valve 50 increases, the differential pressure across the proportional solenoid valve 50 exceeds the relief pressure of the relief valve 61, and the relief valve 61 opens. Therefore, the pressure in the discharge passage 13 is discharged to the tank 12 through the relief passage 17 . Thus, even if the piston rod 22 of the hydraulic cylinder 20 moves to the stroke end, the pressure in the discharge passage 13 is kept below the cracking pressure of the check valve 64 . Therefore, excessive pressure is suppressed from acting on the seal members in each configuration of the pump 11 , the hydraulic cylinder 20 and the wing opening/closing device 100 .

The cracking pressure of the check valve 64 is higher than the pressure used by the pump 11 and the hydraulic cylinder 20 during normal operation, and is set to a pressure that is permissible according to the specifications of the pump 11 and the hydraulic cylinder 20 . That is, the check valve 64 is set not to open during normal operation of the wing opening/closing device 100 . Also, the cracking pressure of the check valve 64 is higher than the pressure on the upstream side of the proportional solenoid valve 50 when the differential pressure across the proportional solenoid valve 50 reaches the set differential pressure, regardless of the degree of opening of the proportional solenoid valve 50. is set to

Here, in order to facilitate understanding of the relief mechanism 60, a comparative example shown in FIG. 4 will be described. The comparative example shown in FIG. 4 differs from the above embodiment in that the relief mechanism 60, specifically, the pilot passage 62, the drain passage 63, and the check valve 64 are not provided. That is, the relief valve 61 according to the comparative example does not open the relief passage 17 in accordance with the differential pressure across the proportional electromagnetic valve 50, and does not have two stages of operating pressure.

In the wing opening/closing device 200 according to the comparative example, the relief pressure of the relief valve 61 is set to a pressure (allowable pressure) higher than the normal operating pressures of the pump 11 and the hydraulic cylinder 20 . In the wing opening/closing device 200 according to the comparative example, the proportional electromagnetic valve 50 does not open even if the differential pressure across the proportional solenoid valve 50 increases, and does not open until the discharge pressure of the pump 11 reaches the relief pressure. Therefore, even if the opening degree of the proportional solenoid valve 50 is controlled to be small and the discharge pressure of the pump 11 rises, the relief valve 61 does not operate quickly, and the discharge pressure of the pump 11 reaches a relatively high relief pressure. Rise. In this case, the load on the pump 11 is large, and the power consumption is accordingly increased.

On the other hand, in this embodiment, even if the discharge pressure of the pump 11 is less than the set pressure which is the allowable pressure of the hydraulic cylinder 20, if the differential pressure across the proportional solenoid valve 50 reaches the set differential pressure, the relief valve 61 opens. Therefore, even if the opening of the proportional solenoid valve 50 is controlled to be small, the relief valve 61 operates quickly to suppress an excessive increase in the discharge pressure of the pump 11, and the discharge pressure of the pump 11 reaches the set pressure. can be prevented.

As described above, in the wing opening/closing device 100, the speed of the expansion and contraction operation of the hydraulic cylinder 20 is controlled by controlling the amount of power supplied to the solenoid 51 of the proportional solenoid valve 50 to adjust the opening degree of the proportional solenoid valve 50. be. Therefore, the opening and closing operation of the wing 2 can be started and stopped at a low speed, and the impact at the start and stop of movement can be reduced.

Further, when the flow rate is controlled by the proportional solenoid valve 50, if the differential pressure across the proportional solenoid valve 50 is greater than the set differential pressure, the discharge pressure of the pump 11 is used in each component of the hydraulic cylinder 20 and the wing opening/closing device 100. The relief valve 61 opens to discharge the pressure in the discharge passage 13 to the tank 12 even when the pressure is lower than the set pressure, which is the allowable pressure of the seal member. Therefore, the discharge pressure of the pump 11 is controlled so as not to exceed the allowable pressure to protect the pump 11 and the hydraulic cylinder 20, and even if the flow rate is controlled by the proportional solenoid valve 50, the increase in the load on the pump 11 is suppressed. , can save energy.

Generally, in order to control the flow rate of the hydraulic oil supplied to the hydraulic cylinder and thereby control the speed of the expansion and contraction of the hydraulic cylinder, the rotation speed of the electric motor is controlled (changed) to control the discharge flow rate of the pump. It is also possible. However, the control of the rotational speed of the electric motor is affected by the inertial force of the rotating electric motor and pump, the load pressure due to the gravity of the wing, and the like. Therefore, even if electric power is supplied to the electric motor so as to achieve a desired rotation speed, a response delay occurs, making it difficult to immediately control the rotation speed of the electric motor to the desired rotation speed.

On the other hand, in the wing opening/closing device 100 , the expansion and contraction operation of the hydraulic cylinder 20 is controlled by controlling the opening degree of the proportional electromagnetic valve 50 . Since the proportional electromagnetic valve 50 is less susceptible to the inertia of the pump 11 and the like and the load pressure, it is possible to control the speed of the expansion and contraction of the hydraulic cylinder 20 with good responsiveness.

Moreover, since it is not the structure which changes the rotation speed of the electric motor 10, in the wing opening/closing apparatus 100, the electric motor 10 can utilize what is called a constant speed motor which operates at a constant speed by supplying an electric current. In general, an electric motor with high-precision controllability has a complicated structure, so its durability is low and its manufacturing cost is high as compared with a constant-speed motor. Therefore, by using a constant-speed motor for the electric motor 10, the manufacturing cost of the wing opening/closing device 100 can be reduced, and since a complicated structure is not required, the durability can be improved. It should be noted that the electric motor 10 is not limited to a constant speed motor, and may be a motor whose rotational speed is controllable. In general, the lower the rotation speed of a pump such as a gear pump, the lower the pump efficiency. Therefore, even if the electric motor 10 is not a constant speed motor, it is desirable to control the rotation speed of the electric motor 10 to be constant. According to this, it is possible to suppress the change in the pump efficiency due to the change in the rotation speed of the electric motor 10, so that the hydraulic cylinder 20 can be stably operated.

Further, when the rotation of the electric motor is controlled, the risk of failure of the electric motor increases due to the rotation speed control, and if the electric motor fails, the wing cannot be opened and closed. On the other hand, since the wing opening/closing device 100 is not configured to control the rotation speed of the electric motor 10, the risk of failure of the electric motor 10 associated with rotation speed control is reduced. Further, even if the proportional solenoid valve 50 fails due to the control of the proportional solenoid valve 50, by providing means for manually switching the proportional solenoid valve 50, the wing 2 can be opened and closed. Therefore, even if the proportional solenoid valve 50 fails, it is possible to prevent the wing 2 from continuing to stop at the intermediate position. It doesn't affect itself. Therefore, by rotating the electric motor 10 at a constant speed and controlling the operation of the hydraulic cylinder 20 by the proportional solenoid valve 50, the wing opening/closing device 100 can be stably operated.

According to the above embodiment, the following effects are obtained.

The wing opening/closing device 100 is not configured to control the number of revolutions of the electric motor 10 , but by adjusting the opening degree of the proportional electromagnetic valve 50 , the expansion and contraction operation of the hydraulic cylinder 20 is controlled. Since the proportional solenoid valve 50 is less susceptible to the inertia of the pump 11 and the like and the load pressure compared to the case of controlling the rotation speed of the electric motor 10, it is possible to control the speed of the expansion and contraction of the hydraulic cylinder 20 with good responsiveness. can. Further, generally, the amount of electric power required for switching the position of the proportional solenoid valve 50 is smaller than the amount of electric power required for controlling the rotational speed of the electric motor 10 . Therefore, in the wing opening/closing device 100, energy can be saved as compared with the case where the electric motor 10 is controlled in rotation speed.

In the wing opening/closing device 100 , when the pressure in the discharge passage 13 reaches the cracking pressure of the check valve 64 , the relief valve 61 opens and part of the hydraulic oil discharged from the pump 11 is discharged to the tank 12 . . As a result, the discharge pressure of the pump 11 is prevented from suddenly increasing and excessive load being applied to the pump 11 . Further, when the differential pressure across the proportional solenoid valve 50 reaches the relief pressure of the relief valve 61, even if the pressure in the discharge passage 13 is less than the cracking pressure of the check valve 64, the relief valve 61 opens to release the pump 11. A portion of the discharged hydraulic oil is discharged to the tank 12 . In this manner, since the hydraulic fluid discharged from the pump 11 can be discharged before the pressure in the discharge passage 13 reaches the cracking pressure of the check valve 64, the discharge pressure of the pump 11 increases when the hydraulic cylinder 20 operates at low speed. can be suppressed and energy can be saved.

Further, in the wing opening/closing device 100, the relief mechanism 60 is provided with the relief valve 61 and the check valve 64, so that the relief passage 17 is opened by operating pressure in two stages. For this reason, according to this embodiment, compared to a form in which two levels of operating pressure are realized by opening two relief passages by two relief valves, the device configuration can be made compact and the manufacturing cost can be reduced. can be reduced.

In addition, in the wing opening and closing device 100, as described above, power consumption can be suppressed and energy can be saved, so the battery (not shown) for driving the electric motor 10 etc. is small in capacity and compact. can do. Thereby, while being able to lighten the weight as the wing opening/closing apparatus 100 whole, the wing opening/closing apparatus 100 can be reduced in size. As the wing opening/closing device 100 is thus reduced in weight and size, the loading weight of the truck 1 on which the wing opening/closing device 100 is mounted can be increased, and the cargo space of the truck 1 can be increased.

In addition, since the wing opening and closing device 100 is not configured to control the rotation speed of the electric motor 10, by using a constant speed motor for the electric motor 10, the manufacturing cost of the wing opening and closing device 100 can be reduced, and durability can be improved. can be improved. Even if a constant speed motor is not used, the rotation speed of the electric motor 10 can be controlled to be constant. can be activated by Furthermore, since there is no need to change the rotation speed of the electric motor 10, the risk of failure of the electric motor 10 due to rotation speed control is reduced.

Further, in general, in the wing opening/closing device, the wing may receive an external force such as wind while the wing is being opened/closed, which may cause the hydraulic cylinder to unintentionally expand and contract. On the other hand, in the wing opening/closing device 100 , the relief mechanism 60 has a throttle 66 provided in the pilot passage 62 and a throttle 67 provided in the drain passage 63 . Therefore, even if an external force that unintentionally expands and contracts acts on the hydraulic cylinder 20 , the pressure fluctuations in the pilot passage 62 and the drain passage 63 are mitigated by the resistance of the throttles 66 and 67 . Therefore, unintentional activation of the relief valve 61 and the check valve 64 is suppressed. More specifically, chattering and hunting of the relief valve 61 and the check valve 64 caused by pressure fluctuations in the pilot passage 62 and the drain passage 63 due to external forces are suppressed. Therefore, the operation of the wing opening/closing device 100 can be stabilized, and failure of the relief valve 61 and the check valve 64 can be suppressed.

Next, modified examples of the present invention will be described.

In the above embodiment, the proportional solenoid valve 50 is of the normally closed type. On the other hand, the proportional solenoid valve 50 may be of a normally open type. However, when the wing 2 is stopped, it is desirable to stop the supply of hydraulic oil to the hydraulic cylinder 20 (more specifically, the control valve 40). Therefore, if the proportional solenoid valve 50 is of the normally open type, it is necessary to turn off the discharge passage 13 by energizing the solenoid 51 in order to stop the supply of hydraulic oil to the hydraulic cylinder 20 . Therefore, the proportional electromagnetic valve 50 is desirably configured such that hydraulic oil is not supplied to the hydraulic cylinder 20 at the time of demagnetization, specifically a normally closed type. According to this, it is not necessary to energize the solenoid 51 in order to stop the supply of hydraulic oil to the hydraulic cylinder 20, so the control of the proportional solenoid valve 50 is facilitated and energy can be saved.

Further, in the above embodiment, the case where the fluid pressure device is the wing opening/closing device 100 has been described. The fluid pressure device is not limited to this, and may be applied to other devices. Further, in the above embodiment, the fluid pressure actuator is the hydraulic cylinder 20 that expands and contracts by supplying and discharging hydraulic oil. The fluid pressure actuator is not limited to this, and may be another type such as a hydraulic (fluid pressure) motor that is rotationally driven by supply and discharge of hydraulic oil.

Further, in the above-described embodiment, the relief mechanism 60 has two stages of working pressure. On the other hand, the configuration in which the relief mechanism 60 has two stages of operating pressure is not essential, and the relief mechanism 60 only needs to operate according to at least the differential pressure across the proportional electromagnetic valve 50 . Further, even if the relief mechanism 60 has two stages of operating pressure, the configuration of the relief mechanism 60 is not limited to that of the above embodiment. Although illustration is omitted, for example, the relief mechanism 60 is provided in a second relief passage branching from the discharge passage 13 instead of the check valve 64 in the above embodiment, and is opened at a relief pressure higher than the relief pressure of the relief valve 61. A configuration having a second relief valve may be employed.

Configurations, functions, and effects of embodiments of the present invention will be collectively described below.

The wing opening/closing device 100 includes a hydraulic cylinder 20 that opens and closes the wing 2 by operating hydraulic fluid discharged from a pump 11 driven by an electric motor 10, and a flow rate of the hydraulic fluid supplied from the pump 11 to the hydraulic cylinder 20. a discharge passage 13 that guides hydraulic fluid discharged from the pump 11 and is provided with the proportional solenoid valve 50; and a relief mechanism 60 for opening and closing the relief passage 17. The relief mechanism 60 opens the relief passage 17 when the differential pressure across the proportional electromagnetic valve 50 reaches a predetermined set differential pressure. .

In this configuration, the speed of the hydraulic cylinder 20 is controlled by controlling the flow rate of hydraulic oil supplied to the hydraulic cylinder 20 by the proportional solenoid valve 50 . When the differential pressure across the proportional solenoid valve 50 reaches the set differential pressure of the relief mechanism 60 , the relief passage 17 is opened and part of the hydraulic fluid discharged from the pump 11 is discharged to the tank 12 . In this manner, the relief mechanism 60 operates according to the differential pressure across the proportional solenoid valve 50. Therefore, even if the discharge pressure of the pump 11 rises due to the flow rate control by the proportional solenoid valve 50, the relief mechanism 60 is quickly released. It is possible to suppress an increase in the discharge pressure of the pump 11 by operating at a high speed. Therefore, power consumption in the wing opening/closing device 100 is suppressed, and energy can be saved.

Further, in the wing opening/closing device 100, the relief mechanism 60 includes a relief valve 61 provided in the relief passage 17 and a pilot pressure exerting an urging force to close the relief passage 17. Relieves pressure on the downstream side of the proportional electromagnetic valve 50. It has a pilot passage 62 that leads to the valve 61 and a throttle 66 that is provided in the pilot passage 62 and provides resistance to the flow of hydraulic oil passing therethrough.

In this configuration, even if an external force that unintentionally expands and contracts the hydraulic cylinder 20 acts, the resistance applied by the throttle 66 suppresses fluctuations in the pressure guided to the relief valve 61 through the pilot passage 62 . Thereby, it is possible to suppress the relief valve 61 from operating unintentionally.

Further, in the wing opening/closing device 100, the relief mechanism 60 is configured to open the relief passage 17 when the pressure in the discharge passage 13 reaches a predetermined set pressure, and the set pressure is higher than the set differential pressure.

In this configuration, when the pressure in the discharge passage 13 reaches the set pressure, the relief passage 17 is opened by the relief mechanism 60 and part of the hydraulic oil discharged from the pump 11 is discharged to the tank 12 . As a result, the discharge pressure of the pump 11 is prevented from suddenly increasing and excessive load being applied to the pump 11 . When the differential pressure across the proportional solenoid valve 50 reaches the set differential pressure, the relief passage 17 is opened and part of the hydraulic oil discharged from the pump 11 is released even if the pressure in the discharge passage 13 is less than the set pressure. is discharged to the tank 12. Since the hydraulic fluid discharged from the pump 11 can be discharged before the pressure in the discharge passage 13 reaches the set pressure, an increase in the discharge pressure of the pump 11 when the hydraulic cylinder 20 operates at low speed can be suppressed. Therefore, power consumption can be suppressed while suppressing overload on the pump 11 and the electric motor 10, and the wing opening/closing device 100 can be further energy-saving.

Further, in the wing opening/closing device 100, the relief mechanism 60 only allows the flow of hydraulic oil from the drain passage 63 branching from the pilot passage 62 and communicating with the tank 12 and the pilot passage 62 provided in the drain passage 63 to the tank 12. The set pressure is the cracking pressure at which the check valve 64 opens, and the set differential pressure is the relief pressure at which the relief valve 61 opens.

In this configuration, a check valve 64 having a cracking pressure, which is a set pressure, is provided in a drain passage 63 that branches off from the pilot passage 62 and communicates with the tank 12 . As a result, the relief mechanism 60 functions as a safety valve that opens at the set pressure, so there is no need to provide a separate safety valve. Furthermore, since a passage provided with a safety valve is not required, the passage configuration in the wing opening/closing device 100 can be simplified. Therefore, the wing opening/closing device 100 can be made more compact.

Although the embodiments of the present invention have been described above, the above embodiments merely show a part of application examples of the present invention, and the technical scope of the present invention is not limited to the specific configurations of the above embodiments. do not have.

Reference Signs List 2, 3 Wing 4 Luggage chamber 10 Electric motor 11 Pump 12 Tank 13 Discharge passage 17 Relief passage 19 Branch passage 20 Hydraulic cylinder (fluid pressure actuator) 40 Control valve 50, 150 Proportional electromagnetic valve 60 Relief mechanism 61 Relief valve 62 Pilot passage 63 Drain passage 64 Check valve 66 Throttle (throttle portion) 100 Wing opening/closing device (fluid pressure device)

Claims (3)

an electric motor rotated by power supply;
a pump driven by the electric motor;
a fluid pressure actuator operated by the working fluid discharged from the pump;
a proportional solenoid valve that controls the flow rate of the working fluid supplied from the pump to the hydraulic actuator;
a discharge passage that guides the working fluid discharged from the pump and is provided with the proportional solenoid valve;
a relief passage that branches from the discharge passage upstream of the proportional solenoid valve and communicates with a tank;
a relief mechanism that opens and closes the relief passage,
The relief mechanism is
opening the relief passage when the differential pressure across the proportional solenoid valve reaches a predetermined set differential pressure;
opening the relief passage when the pressure on the downstream side of the proportional solenoid valve in the discharge passage reaches a predetermined set pressure;
When the differential pressure across the proportional solenoid valve reaches the set differential pressure, the relief passage is opened even if the pressure on the downstream side of the proportional solenoid valve in the discharge passage is less than the set pressure,
A fluid pressure device , wherein the set pressure is higher than the set differential pressure . The relief mechanism is
a relief valve provided in the relief passage;
a pilot passage for guiding the pressure on the downstream side of the proportional solenoid valve to the relief valve as pilot pressure exerting a biasing force to close the relief passage;
2. The fluid pressure device according to claim 1, further comprising a restrictor provided in said pilot passage and applying resistance to the flow of working fluid passing therethrough. The relief mechanism is
a relief valve provided in the relief passage;
a pilot passage for guiding the pressure on the downstream side of the proportional solenoid valve to the relief valve as pilot pressure exerting a biasing force to close the relief passage;
a drain passage that branches from the pilot passage and communicates with the tank;
a check valve that is provided in the drain passage and allows only the flow of working fluid from the pilot passage toward the tank;
The set pressure is a cracking pressure at which the check valve opens,
2. A fluid pressure device according to claim 1 , wherein said set differential pressure is a relief pressure at which said relief valve opens.

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