JPH0790999B2 - Fluid pressure elevator - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid pressure elevator, and more particularly to controlling the flow rate of fluid supplied to or discharged from a fluid pressure cylinder to control the speed of the fluid pressure cylinder. The present invention relates to a hydraulic elevator that controls and controls the speed of a car that is directly or indirectly supported by a cylinder.

[Conventional technology]

In a fluid pressure elevator that controls the pressure fluid to control the speed of the fluid pressure cylinder and the speed of the car,
Known methods include a method of controlling pressure fluid with a flow control valve in response to a speed command, a method of controlling pressure fluid by controlling the rotation speed of a fluid pressure pump with a motor, and the like. In particular, with the progress of electronic control devices and control technologies, it has become easier to control the rotation speed of a motor by an inverter, and therefore the practicality of a fluid pressure elevator in which the rotation speed of a fluid pressure pump is directly controlled by the motor is increasing. .

As an example showing this type of conventional technique, Japanese Patent Laid-Open No. 57-
81073 and JP-A-60-57471 are available.

In the method of controlling the speed of the car by controlling the number of rotations of the motor, if the number of rotations exceeds the rated value due to a failure of the control device, etc., it may be possible to go up or down beyond the rated speed of the car. . In addition, when the driving power becomes zero due to a power outage or the like, the car may be in a free fall state and may drop beyond the safe speed. In such a case, it is essential to ensure safety.

[Problems to be Solved by the Invention]

In a fluid pressure elevator that controls the speed of a car by controlling the rotation speed of a motor, changes in the driving direction, the number of passengers, and the fluid temperature cause a large change in acceleration at the time of start-up, which reduces ride comfort. The speed at which the car ascends or descends can be unacceptably high. That is, when the check valve for holding the position of the car is opened at the time of startup, the fluid is rapidly compressed due to the pressure difference between the front and the rear of the valve, resulting in a large acceleration fluctuation. Further, when the pump is driven at a speed higher than the rated speed due to an abnormality in the control device or when the driving power is lost due to a power failure or the like, the vehicle may travel at a speed higher than the allowable speed.

An object of the present invention is to realize a constant speed characteristic regardless of the driving direction of the elevator, the number of passengers, and the fluid temperature, and
It is an object of the present invention to provide a fluid pressure elevator which can obtain a good speed characteristic, that is, a good ride comfort by rapidly decelerating the car speed of an elevator even in an emergency, and has high safety and reliability.

[Means for Solving the Problems]

The above-mentioned object is a control valve or a control valve improved in the structure and control method of a pilot operated check valve which is usually used in a flow path connecting a fluid pressure pump and a fluid pressure cylinder for holding the position of a car. And an overspeed prevention valve are arranged, and these valves are provided with the flow rate control capability in the initial stage of startup and the maximum flow rate limiting function. Here, the control capability at the initial stage of startup means that the motor is started in accordance with the start command and the control valve is also controlled to smoothly start, while the control valve is automatically operated when the power source is stopped in case of an emergency such as a power failure. Is the ability to reduce the flow rate of the pressure fluid flowing out of the fluid pressure cylinder to decelerate and stop the car. The maximum flow rate limiting function is used to automatically control the control valve by utilizing the fact that when the fluid flowing through the control valve exceeds the specified flow rate, the pressure drop at the control valve and overspeed prevention valve also exceeds the specified value and increases. The function is to narrow the opening area, limit the flow rate or close the valve to stop the flow (stop the car).

That is, in order to achieve the above object, the present invention controls the flow rate of the fluid supplied to or discharged from the fluid pressure cylinder by controlling the rotation speed of the fluid pressure pump, and directly controls the fluid pressure cylinder. Or, in a fluid pressure elevator that indirectly raises or lowers the car, between the fluid pressure pump and the fluid pressure cylinder, when the pilot valve is de-energized, the pilot pressure fluid is discharged to close the main valve. Operated check valve is installed to regulate the valve opening when the fluid flows in the reverse direction to be smaller than the valve opening when the fluid flows in the forward direction. The present invention proposes a fluid pressure elevator equipped with a stopper for a valve body that applies a force in the closing direction to the valve body.

The valve body of the check valve may be provided with a skirt portion having an orifice that gradually increases or decreases the opening area of the check valve according to the operation of the valve body of the check valve.

Further, a control means for gradually opening the check valve to almost balance the fluid pressure between the fluid pressure cylinder and the fluid pressure pump with the pressure of the fluid pressure cylinder and then activating the fluid pressure pump to lower the car is provided. It is desirable to prepare.

Further, a piston that opens the check valve so that the fluid flows in the reverse direction according to the control command and a valve body that controls the flow of the fluid are relatively slidably fitted together, and when the fluid flows in the forward direction, It can also be configured such that only the valve body moves.

In order to achieve the above object, the present invention also controls the flow rate of the fluid supplied to or discharged from the fluid pressure cylinder by controlling the rotation speed of the fluid pressure pump, and the fluid pressure cylinder directly controls the flow rate. Alternatively, in a fluid pressure elevator that indirectly raises or lowers a car, if the outlet pressure of the fluid pressure pump reaches or exceeds a predetermined value in the flow channel that branches from the flow channel that connects the fluid pressure pump and the fluid pressure cylinder. A relief valve for discharging the fluid discharged from the pump to the fluid tank is arranged, a shaft is provided on the valve body of the relief valve, and one of the valve body and the shaft is controlled by the pressure from the pilot relief valve to control the valve body and the shaft. A fluid pressure elevator in which the other one is controlled by the pressure from the pilot switching valve and the relief valve and the unload pressure can be set in the relief valve is proposed.

The pilot chamber is connected to the pilot relief valve and the pilot switching valve, and a stopper that mechanically restricts the position of the valve element of the relief valve when the pilot switching valve is excited is provided, and the relief valve is provided with relief pressure and unload pressure. To be configurable.

[Action]

In the present invention, the motor, that is, the pump is started after waiting for the equilibrium of the fluid pressures before and after the start-up control valve, so that smooth operation is possible and the ride comfort of the elevator is improved.

Further, a flow rate control valve or a combination of a flow rate control valve and a throttle valve is arranged in the flow path that connects the fluid pressure pump and the fluid pressure cylinder. When the flow rate of the fluid flowing through the control valve or the throttle valve exceeds the specified value, the pressure drop at the flow control valve or the throttle valve also exceeds the specified value and becomes large. In the present invention, the control valve is operated by utilizing this pressure drop, the opening area of the flow control valve is automatically narrowed, and the flow rate flowing through the control valve is limited. Although the flow direction of the fluid flowing through the control valve changes in response to the rise or fall of the elevator, in the present invention, only the pressure drop in the control valve is dealt with regardless of the flow direction of the fluid. To operate. Therefore, the control valve operates irrespective of the operation direction of the car only in accordance with the pressure loss of the fluid generated by the fluid flowing through the control valve or the combination of the control valve and the throttle valve, and the flow rate of the fluid flowing through the control valve is Limited. As a result, the car speed of the elevator is limited to the specified value or less and the elevator is stopped safely, and the safety and reliability of the elevator are secured.

〔Example〕

FIG. 1 is a fluid pressure circuit diagram showing an embodiment of a fluid pressure elevator according to the present invention. In the figure, 1 is a fluid pressure cylinder that directly or indirectly drives the car 10 (here, a direct drive system), 2 is a control valve (here, a pilot operated check valve with a flow rate control function), 4 is an unload function With relief valve, 5 is a suction valve for protecting the pump, 6 is a fluid pressure pump capable of rotating in the forward and reverse directions, 7 is a motor, 8 is a filter,
9 is a fluid tank. 11 is an inverter for driving the motor 7, 12 is an elevator control device, 13 is a pilot valve,
15, 16 and 17 are flow paths.

The control valve 2 is a pilot operated check valve consisting of a main valve 20 and pilot valves 21a, 21b, and normally allows a flow to the fluid pressure cylinder 1 as shown in the figure and shuts off the reverse flow. is doing. When a command is input to the pilot valves 21a and 21b, the main valve 20 is opened and the fluid can be discharged from the fluid pressure cylinder 1. Here, turn the pilot valves 21a and 21b ON-O.
Although the FF valve is used, a two-position three-way valve has the same effect and is not limited to the illustrated circuit.

The relief valve 4 is provided for unloading operation for controlling the fluid temperature and protection of the circuit, and the suction valve 5 is for the flow path 15
It is provided to prevent a from becoming a vacuum.

In this embodiment having such a configuration, a case where the car 10 is raised and a case where the car 10 is lowered will be described.

(1) At the time of rising The inverter 11 is driven based on the rising command from the control device 12 to start the motor 7 (the rotation direction at this time is positive rotation), and the motor is accelerated to the rated speed according to the speed signal and driven. To do. The liquid passes through the filter 8, is pressurized by the fluid pressure pump 6, increases in proportion to the pump speed proportional to the speed signal, passes through the control valve 2 acting as a check valve, and is supplied to the fluid pressure cylinder 1. .

As a result, the fluid pressure cylinder 1 that directly or indirectly drives the car 10 is activated, and the speed signal (motor rotation speed)
Is gradually increased to the rated speed in proportion to. On the other hand, if the number of rotations of the motor 7 is reduced by the deceleration signal (speed signal),
Contrary to the case of acceleration, fluid pressure cylinder 1 (car 10)
Slows down and eventually stops. After that, even if the command is released, the control valve 2 is closed and the position of the car 1 is maintained.

At this time, if the outlet pressure of the pump 6 becomes higher than the specified value (relief pressure) due to some abnormality, the relief valve 4 operates to discharge the discharge fluid of the pump 6 to the tank 9 and prevent the abnormal pressure rise of the fluid pressure circuit. , Prevent damage to equipment and piping.

(2) At the time of lowering The pilot valves 21a and 21b of the control valve 2 are operated based on the lowering command from the control device 12, the main valve 20 is gently switched, and the fluid pressure cylinder 1 and the fluid pressure pump 6 are made to communicate with each other.
The pressures in the flow paths 15a and 15c are balanced. After that, the motor 7 is started in the opposite direction to the upward movement (reverse rotation), accelerated according to the speed signal, and the pump 6 returns the high-pressure fluid in the fluid pressure cylinder 1 to the tank 9. Therefore, the fluid pressure cylinder 1 and the car
10 is descent activated and accelerated.

In this case, the pump is started after the fluid in the fluid cylinder 1 in the flow path between the control valve 2 and the pump 6 is in equilibrium, so that the smooth start can be performed at the time of the descent start and there is no start shock. The acceleration of the motor 7
By driving at rated speed, decelerating, and stopping, the car 10 also accelerates,
Stops after traveling through the rated speed and deceleration. After that, if the signals to the pilot valves 21a and 21b are released, the main valve 20 also returns and returns to the initial state.

When the main valve 20 is suddenly switched at the time of the descent start, the fluid in the flow path 15a is rapidly compressed, which causes a large shock. Therefore, in order to secure a good ride comfort of the elevator, it is preferable to switch the main valve 20 gently. For that purpose, it is more preferable to use, as the pilot valves 21a and 21b, a PWM driven valve or a valve that operates in proportion to a command.

At this time, an imbalance occurs between the opening operation of the control valve 2 and the starting operation of the motor 7, so that the suction flow rate of the pump 6 is increased by the cylinder 1.
However, in that case, the fluid may be replenished from the tank 9 via the suction valve 5, the circuit 15a may be evacuated, and cavitation may occur, which may damage the pump 6. To prevent.

(3) In an emergency When the driving power is lost due to a power failure or the like, the car 10 starts to drop at an excessive speed due to its own weight, which is inconvenient for safety. In such a case, the control command is released, so
The excitation of the pilot valves 21a and 21b is released, the pilot valves 21a and 21b return to the reference position (state shown), and the main valve 20 quickly returns to the state shown. Therefore, the flow of the fluid from the fluid pressure cylinder 1 is cut off to decelerate and stop the car 10, so that the safety is dramatically improved. Even in an emergency other than a power failure, the elevator can be stopped in the same manner by releasing the control signal from the pilot valve. Examples of such cases include overspeed lowering due to an abnormality in the control device and breakage of the coupling between the pump and the motor.

FIG. 2 is a fluid pressure circuit diagram showing another embodiment of the present invention. The same symbols as those in FIG. 1 indicate parts having the same functions. The difference from the embodiment of FIG. 1 is that an acceleration prevention valve 3 is added to the flow path 15a between the control valve 2 and the pump 6. The acceleration prevention valve 3 is composed of a main valve 30 and a throttle valve 31, and operates when the flow rate of the fluid flowing through the valve 3 on the descending side exceeds a specified value.
That is, when the flow rate flowing through this valve exceeds the specified value and the pressure difference before and after this valve becomes large, the main valve 30 operates due to this pressure difference, and the circuit is quickly interrupted to stop the car 10. By doing so, in addition to power failure, acceleration due to malfunction of the control device can be prevented, and safety is improved.

FIG. 3 is a sectional view showing the structure of an embodiment of the control valve 2. The main valve 20 includes a valve body 22, a valve body 23, a spring 20c, and a piston 2
The ports 22a and 22b are connected to the flow paths 15a (15b) and 15c, respectively, with 4 and the stopper 25 as main constituent elements. The valve body 23 has an orifice 23b in its skirt portion 23a, and the skirt portion 23a
It can slide on the valve body 22 using a and the shaft 23c as a guide, and
It is pressed against the valve seat with c. The piston 24 is driven by the pilot valves 21a and 21b, and drives the valve body 23. Piston 2
The operation range of 4 is limited by the stopper 25.

When excited, the pilot valves 21a, 21b supply or discharge pilot fluid to the piston chamber 22f. Normally, the piston chamber 22f is opened to the tank 9, but when the pilot valve 21a is excited, the fluid chamber is opened via the throttle 21c.
When 22d and the piston chamber 22f are connected and the pilot valve 22b is excited, the fluid chamber 22 is shut off from the tank 9.

(1) Ascending operation The control valve 2 simply acts as a check valve, and the fluid pressure pump 6
The discharged fluid becomes a flow (free flow) from the port 22a (flow path 15a or 15b) to the port 22b (flow path 15c), and pushes up the fluid pressure cylinder 1. At this time, in order to reduce the pressure loss of the fluid flowing through the valve 2, the valve body 23 should be opened sufficiently so that the spring 20
Set c. The speed of the car 10 is controlled by controlling the rotation speed of the pump 6.

(2) Lowering operation The lowering signal excites the pilot valves 21a and 21b to supply high-pressure fluid to the piston chamber 22f, push the piston 24 to displace the main valve body 23, and establish communication between the ports 22a and 22b. The high-pressure fluid in the pressure cylinder 1 is discharged by the fluid pressure pump 6, and the fluid pressure cylinder 1 and the car 10 are lowered. At this time, the throttle 21c controls the operating speed of the valve body 23, and the skirt 23a
The orifice 23b provided in the section gradually increases the opening area between the ports 22b and 22a. This orifice 23b and diaphragm 21c
This prevents the start-up shock of the elevator from occurring. The pilot flow rate may be controlled by configuring the pilot valve with a proportional solenoid valve that operates in proportion to the command, a PWM control valve, or the like.

At this time, the stopper 25 limits the displacement of the piston 24, that is, the opening degree of the main valve 20, so that a constant pressure drop amount is provided with respect to the flow from the ports 22b to 22a. In this way, if the driving power is lost due to a power outage, etc., the main valve 20 will automatically close due to the pressure difference before and after this valve to reduce the discharge flow rate from the cylinder 1, slow down and stop the car 10, and improve safety. Let

When the lowering is completed, the excitation of the pilot valve is released, the high pressure fluid in the piston chamber 22f is discharged, the main valve body 23 is returned to the illustrated state, and the lowering operation is completed. At this time, the pilot valve outlet pressure is atmospheric pressure, and the fluid is discharged from the piston chamber 22f in a short time, so the response time of the main valve is short.

This will be described in detail with reference to FIG. This figure shows the movement of the main valve body 23 and the pressure at the port 22a during the ascending and descending operations.

(1) When rising (dashed line) When the pump 6 is started, the pressure of the port 22a increases due to the discharged fluid, and when the pressure exceeds the cylinder pressure, the fluid flows to the main valve 20
The valve body 23 is pushed open against the force of the weak spring 20c and flows into the port 22b (communication with the cylinder 1). When the pump speed increases from acceleration to full speed according to the command, the flow rate of the valve also increases and the displacement of the main valve body 23 also increases. At this time, the force acting on the main valve body 23 is a small spring force, so the pressure at the port 22a is almost constant regardless of the flow rate of the valve, and is slightly larger than the cylinder pressure Pu (differential pressure ΔPu).
Is. This is because the main valve 20 acts as a check valve with a low cracking pressure.

When the flow rate of the pump 6 decreases and the car 10 stops after decelerating, the valve body 23 displaces and closes substantially in proportion to the flow rate. During this time, the pressure at the port 22a is substantially constant as shown for the reasons described above. When the main valve 20 is closed, the fluid leaking from the pump 6 causes the pressure at the port 22a to drop sharply. That is, the valve body 23 is displaced substantially in proportion to the flow rate, and acceleration, full speed, and deceleration are clearly shown as shown in the figure, but the pressure at the port 22a is a substantially constant value during traveling of the elevator.

(2) When descending (solid line) Energize the pilot valves 21a, 21b and use the piston 24 to move the valve body 2
When 3 is displaced, port 22a communicates with port 22b and the pressure rises. After that, the pump 8 is driven to accelerate the car 10 and run at full speed. The main valve 20 is fully opened slightly earlier than the rotation of the pump 6, but the opening degree at this time is smaller than that at the rising time as described above. Therefore, the port when descending
The difference between the pressure Pd of 22a and the cylinder pressure is ΔPd, which is larger than the differential pressure ΔPu when rising. After that, the pump speed is decelerated and stopped according to the command, and after the pump is stopped, the pilot valve
When the excitation of 21a and 21b is released, the main valve 20 is also returned and the lowering operation is completed as shown in FIG. The pressure difference ΔPd becomes small when the deceleration starts and becomes almost zero at the time of stop, and when the control valve 20 is closed, the pressure Pu at the port 22a suddenly drops.

(3) Emergency stop (dashed-dotted line) An emergency stop may occur for some reason while the fluid pressure elevator is running. At this time, if the car 10 is rising, gravity causes the car to stop temporarily, and then starts to descend, and the descending speed increases. If it is descending, the descending speed increases as it is.

In either case, safety is impaired. Therefore, in the control valve 2 of the present invention, the excitation of the pilot valves 21a, 21b is released to discharge the fluid of the piston valve 22f, and as shown by the alternate long and short dash line in FIG. Valve body 23 due to pressure difference ΔPd
Is forcibly closed to slow down and stop the car 10, which is safe.

As described above, according to the control valve of the present invention shown in FIG. 3, it is possible to provide a fluid pressure elevator which is capable of ascending, descending, and emergency stop, and which is comfortable to ride and highly safe.

FIG. 5 is a sectional view showing the structure of another embodiment of the control valve 2. The same symbols as those in FIG. 3 indicate parts having the same functions.
This embodiment is different from the embodiment of FIG. 3 in that the stopper 25
Is the position. In the embodiment of FIG. 3, the piston 24 is provided with the stopper 25, but in the embodiment of FIG. 5, the displacement of the valve body 23 is directly limited. Since the operation and effect are the same as those in FIG. 3, the description is omitted here.

FIG. 6 is an embodiment similar to the embodiment shown in FIG. 3 or FIG. 4, but has a communication hole for communicating the fluid chambers 22c and 22g with the valve body 23.
23e is provided, and the same fluid pressure as that of the fluid chamber 22c also acts on the fluid chamber 22g to reduce the force exerted by the fluid acting on the valve element 23.
By doing so, even if the pressure difference between the valve body 23 and the valve body 23 is large when the fluid pressure elevator is started, the force for driving the piston 24 can be small. This means that the piston that drives the valve body 23
This means that the pressure receiving area of 24 is small, the flow rate through the pilot valve is small, and the pilot valve may be small. As described above, when the pilot valve is small, the flow rate of the fluid for driving the control valve can be saved, and the startup shock of the fluid pressure elevator is reduced, which is advantageous. Further, when it is necessary to rapidly close the control valve as in the emergency described above, the flow rate of the fluid discharged from the fluid chamber 22f is reduced, and thus the control valve operates at high speed, which is preferable. .

Since the function of the control valve is the same as that of the embodiment shown in FIG. 3 or 4, description thereof will be omitted here. FIG. 7 shows control valve 2
It is sectional drawing which shows the other Example of this. The same symbols as those in FIGS. 3 and 4 indicate parts having the same functions. This embodiment is the third,
The difference from the embodiment of FIG. 4 is the structure of the piston 24 and the stopper 25. That is, the piston 24 is provided slidably on the shaft 23c of the valve body 23, and the stopper 23d prevents the piston 24 from coming off. The piston 24 is slidable in piston chambers 22e and 22f provided in the member 22c of the valve body 22, and its operating range is limited by the stopper 25 while being pushed by the spring 24a.

(1) Ascending operation As in the embodiment shown in FIG. 3, when the elevator is ascending, the pressure fluid from the pump 6 flows from the port 22a, pushes up the valve body 23, and flows into the cylinder 1 from the port 22b. At this time, the piston 24 does not act on the valve element 23, only the valve element 23 operates, and only functions as a check valve.

(2) Lowering operation When lowering, the pilot valves 21a and 21b are excited by a command to supply pilot fluid to the piston chamber 22f, and the piston 24 is pulled up according to the force and fluid pressure of the spring 20c (valve element 23
Also, the fluid pressure cylinder 1 and the fluid pressure pump 6 are gradually communicated with each other, the fluid in the cylinder 1 is discharged by the fluid pressure pump 6, and the car 10 is started down and accelerated. Since the movement amount of the piston 24 is limited by the stopper 25,
At this time, the position of the valve body 23 is the maximum valve opening when descending, and the port
There is a certain pressure difference in the flow from 22b to 22a. As described in FIG. 3, this pressure difference automatically becomes the force for closing the control valve 2 in the event of a power failure or the like. When decelerating and stopping, the rotation speed of the pump 6 is reduced to reduce the discharge flow rate from the cylinder 1, and when stopped, the excitation of the pilot valves 21a and 21b is released and the fluid in the piston chamber 22f is discharged, and the piston 24 and the valve are discharged. Return the body 23 to its original position.

In the event of an emergency such as a power outage, if the pilot valves 21 and 21b are de-excited, the fluid in the piston chamber 22f is discharged, and the valve body 23 is operated by the force of the springs 24a and 24c and the valve, as described in FIG. It is pulled downward due to the pressure difference between the fluid chambers 22d and 22c in the front and rear of the body 23, and the flow path from the ports 22b to 22a is quickly shut off. This causes the car 10 to stop.

FIG. 8 is a sectional view showing the structure of still another embodiment of the control valve 2.

The same symbols as those in FIG. 7 indicate parts having the same functions. The difference between this embodiment and the embodiment of FIG. 7 is the stopper 25. In the embodiment shown in FIG. 7, only the movement amount of the piston 24 is limited, but in the embodiment shown in FIG. 8, the displacement of the valve body 23 is directly limited. Since the action and effect are the same as those of the embodiment shown in FIG. 7, the explanation is omitted here.

FIG. 9 shows an embodiment similar to the embodiment shown in FIG. 7 or FIG. 8 except that the valve body 23 has a communication hole 23 for communicating the fluid chambers 22c and 22g.
By providing e, the same fluid pressure as that of the fluid chamber 22c also acts on the fluid chamber 22g to reduce the force from the fluid acting on the valve element 23.

FIG. 10 is a sectional view showing the structure of an embodiment of the overspeed prevention valve 3. It is composed of a main valve 30 and a throttle 31. Main valve 30 is valve body 32
A valve body 33 and a spring 30c, and has fluid chambers 32c and 32d and ports 32a and 32b connected to the fluid chambers. The throttle 31 is a baffle plate or the like that adjusts the flow passage area according to the flow rate. Disc
The reference numeral 33 has pressure receiving portions 30a and 30b, and receives the pressures of the flow path 15 and the port 32a, respectively. When the pressure Pa of the port 32a is higher than the pressure Pb of the flow path 15 (Pa> Pb), the valve body 33 is in the state shown in the figure, and the ports 32a and 32b are communicated with each other. In the opposite case (Pa <Pb), the valve element 33 receives a force corresponding to the pressure difference between the flow path 15 and the port 32a in the right direction, and when this force becomes larger than the specified value, the valve element
33 moves in the direction of closing the flow path against the spring 30c. That is, when the car 10 is in the lowered state, the fluid flows from the ports 32b to 32a.
When the flow rate exceeds the specified value while flowing in the direction of, the flow path is closed. Ports 32a and 32b due to operation of valve body 33
The pressure difference between and increases further, which encourages movement of the valve disc.

Therefore, if the throttle 31 is adjusted according to the flow rate flowing through the overspeed prevention valve 3, if the flow rate exceeding the specified value flows, the main valve 30
Acts to shut off the ports 32a and 32b and shut off the flow of fluid. This means that the fluid flowing out of the cylinder 1 is shut off, and the car 10 can be safely stopped without increasing the speed higher than the specified speed.

In the figure, a single throttle is illustrated as the throttle 31, but the control valve 2
The same effect can be obtained by using, and is not limited to the illustrated structure. As described above, since the control valve 2 causes a pressure difference when it descends, the structure of the valve device can be simplified by operating the overspeed prevention valve 3 using the pressure difference.

FIG. 11 shows another embodiment of the overspeed prevention valve 3, and FIG. 12 shows its more specific structure. The overspeed prevention valve 3 includes a main valve 30, pilot valves 34 and 35, and a throttle 31. The throttle 31 is a baffle or the like that adjusts the flow passage area according to the flow rate (the throttle 31 may be replaced with the fluid resistance of the control valve 2 as described in FIG. 10). The main valve 30 is composed of a valve body 32, a valve body 33, and springs 30c, 30f, and has fluid chambers 30c, 30d, 30f and ports 30a, 30b, 30e connected to the respective fluid chambers, and each port has a flow path 15
It is connected to a, 15b, 16 (tank 9). The valve bodies 33d and 33e are pressure receiving parts 3
3a and 33b, and receive pressure from pilot valves 34 and 35, respectively. The pilot valves 34, 35 are two-position three-way switching valve bodies, have valve bodies 38, 39, and switch the fluid depending on the operating position of the valve bodies 38, 39. The flow paths 37a, 37d and 37b, 3 are provided on the end surface.
Pressure from ports 30a and 30b is received via 7e.

The pressure Pa at port 30a is greater than the pressure Pb at port 30b (Pa
> Pb), the valve bodies 34 and 35 are in the state shown in the figure, and
37a, 37f and 37e are communicated with each other, and the flow paths 37b and 37d are blocked. In the opposite case (Pa <Pb), the valve bodies 34 and 35 are in the opposite positions to the positions shown in the figure, and connect the flow paths 37c and 37b, 37f and 37d, and block the 37a and 37e. That is, the high pressure side of the ports 30a and 30b is connected to the valve body 3 of the main valve.
The low pressure side of the pressure receiving portion 33a of 3d is connected to the pressure receiving portion 33b of the valve body 33. Therefore, the valve elements 33d and 33e receive a force corresponding to the pressure difference between the ports 30a and 30b in the right direction. When this force becomes larger than the specified value, the valve elements 33d and 33e move against the force of the spring 30c to close the flow path between the ports 30a and 30b. Disc
Due to the action of 33, the pressure difference between the ports 30a and 30b becomes larger and larger, which promotes the action of the valve body. That is, if the throttle 31 is adjusted according to the flow rate flowing through the overspeed prevention valve 3, the main valve 30 operates when the flow rate exceeding the set value flows, shutting off the port 30b, and opening the ports 30a and 30e. To communicate.

This means that the discharge fluid of the pump 6 is returned to the tank 9 and the flow path to the cylinder 1 is closed when the elevator is rising, and the fluid flowing out of the cylinder 1 is removed when the elevator is descending. To shut off and supply fluid from the tank 9 to the pump 6, in either case
10 will be stopped safely without increasing the speed above the specified speed. Further, as described above, the pump is protected from an abnormal increase in pump discharge pressure or an abnormal low pressure (vacuum) in suction pressure.

When the temperature of the fluid changes, the viscosity also changes, the control characteristics of the control valve and the volumetric efficiency of the pump change, leading to a decrease in riding comfort and an increase in energy loss. Used in the range. However, using a heater as an energy source for heating this fluid causes an increase in price. Therefore, in the embodiment of the present invention, the relief valve 4 is provided with a structure in which the set pressure can be changed in two stages so that the unload operation can be performed, and the fluid temperature is raised by the unload operation.

FIG. 13 is a sectional view showing the structure of an embodiment of the relief valve 4 which also serves as an unload valve. The relief valve 4 has a valve body 40, a valve body 41, a pilot valve 43, and an unload pressure setting pilot valve 44 as main constituent elements. The valve body 41 is a poppet type having a shaft 41a, and forms fluid chambers 40b (back surface of the poppet), 40e (shaft end surface) and 40c (side surface of the poppet) between the valve body 40 and the valve body 40. The fluid chamber 40d communicates with the port 40a via the throttle 42, and communicates with the fluid chamber 40e via the throttle 42a. port
40a, 40b are connected to the flow paths 15a, 16 respectively. The pilot valve 43 communicates with the fluid chamber 40d, and has a valve body 43a, a spring 43b, and a screw 4
3c and adjust the pressing force of the spring 43b to adjust the fluid chamber 4
Set 0d relief pressure. The other pilot valve 44 communicates with the fluid chamber 40e and includes a valve element 44a, a spring 44b and a solenoid 44c and is normally closed. However, when the solenoid 44c is excited, the fluid chamber 40e is opened to the atmosphere.

In the relief valve 4, the force acting on the valve body 41 from the fluid chambers 40d, 40e at normal times is larger than the force acting on 40a, 40c, and the ports 40a and 40b are shut off as shown in the figure (port 40b
Is the tank pressure). When the pressure of the port 40a becomes larger than the pressure set by the pilot valve 43, the pilot valve 43 opens and the fluid in the fluid chambers 40d and 40e is discharged to change the poppet 41 to the force of the spring 41b or the pressure of the fluid chambers 40d, 40e. Displace against
The fluid is made to flow from the ports 40a to 40b, and the pressure at the port 40a is not increased further.

When the relief valve 4 is operated as an unload valve, the pilot valve 44 is excited to open the fluid chamber 40e to the tank 9, so that the force acting on the back surface of the poppet 41 is reduced by the cross-section integral of the shaft 41a. The main valve opens even when the pressure at the port 40a is lower than the relief pressure. This pressure is the unload pressure, and the difference between the relief pressure and the unload pressure is determined by the size of the shaft 41a. That is, the unload pressure is always set smaller than the relief pressure by a constant value regardless of the set value of the relief pressure.

FIG. 14 is a sectional view showing the structure of another embodiment of the relief valve. The same symbols as those in FIG. 13 represent the parts having the same functions.
The relief pressure is set in the same manner as in the embodiment shown in FIG. 13, and is set by the pilot valve 43. Stopper for setting the unload pressure
The amount of displacement of the valve element 41 is limited by 45, and this is performed. For unloading, the pilot valve 44 is excited to open the fluid chamber 40d to the atmosphere, and the valve body 41 is displaced to the stopper 45 to convert energy loss in this gap into heat. Since the unload pressure is lower than the relief pressure, the amount of displacement of the valve element 41 is greater during unloading than during relief. Therefore, the unload pressure can be set separately from the relief pressure.
In this case, compared with the embodiment shown in FIG. 13, the setting of the unload pressure requires more labor, but the structure of the relief valve is simplified.

FIG. 15 is a fluid pressure circuit diagram of an embodiment different from FIGS. 1 and 2 of the fluid pressure elevator according to the present invention. In the figure, 1 is a fluid pressure cylinder that directly or indirectly drives a car 10, 2 is a pilot operated check valve, 3 is an overspeed prevention valve, 4 is a relief valve that also serves as an unload valve, and 5 is pump protection. Check valve, 6 is a fluid pressure pump capable of rotating in the forward and reverse directions, 7 is a motor, 8 is a filter and 9 is a fluid tank. Reference numeral 11 is an inverter for driving the motor 7, 12 is an elevator control device, and 15, 16, 17 are flow paths.

The pilot operated check valve 2 has a main valve 20 and a pilot valve 21.
In the normal state, the flow of fluid from the fluid pressure cylinder 1 is shut off as shown in the figure, and the flow to the fluid pressure cylinder 1 is allowed. When command is input to pilot valve 21, main valve 20
Is opened, and the fluid can be discharged from the fluid pressure cylinder 1. The overspeed check valve 3 includes a throttle 31, a main valve 30, and a pilot valve 3
It consists of 4 and 35, and normally the fluid is squeezed 31
And through the main valve 30. When the pressure difference before and after the overspeed prevention valve 3 exceeds a preset specified value, that is, when the flow rate exceeds the specified value, the main valve 30 passes through the pilot valves 34, 35.
The main valve 30 is switched by the fluid pressure that acts on the fluid to control the flow of fluid.

In this embodiment having such a configuration, a case where the car 10 is raised and a case where the car 10 is lowered will be described.

(1) At the time of rising Based on the rising command and the speed signal from the control device 12, the inverter 11 is driven to gradually start the motor 7 and accelerate it (the rotation direction at this time is forward rotation). Then, according to the speed signal, the motor 7 is accelerated to the rated rotation speed and further driven at the rated rotation speed. The fluid pressure pump 6 starts in the forward direction,
When accelerated, the fluid passes through the filter 8 and the fluid pressure pump 6
Is inhaled and the pressure is gradually increased. The high-pressure fluid is supplied to the fluid pressure cylinder 1 through the overspeed prevention valve 3 and the pilot operated check valve 2. At this time, the discharge flow rate of the fluid pressure pump 6 also increases as the motor rotation speed increases, and the fluid pressure cylinder 1 is activated and gradually accelerated to the rated speed. The car 10 driven directly or indirectly by the fluid pressure cylinder 1 is also started and accelerated in proportion to the speed signal (motor speed) to reach the rated speed. On the other hand, if the rotation speed of the motor 7 is reduced by the deceleration signal (speed signal), the speed of the fluid pressure cylinder 1 is decelerated, contrary to the case of acceleration, and finally stops. That is, the car 10 also slows down and stops.

(2) At the time of descending The pilot valve 21 of the pilot operated check valve 2 is operated by the descending start signal from the control device 12 to switch the main valve 20. As a result, the fluid pressure cylinder 1 and the pump 6 communicate with each other via the check valve 2 and the overspeed prevention valve 3. Then, according to the speed signal, the motor 7 is started and accelerated in the opposite direction to the upward movement (negative rotation), the high pressure fluid in the fluid pressure cylinder 1 is sucked by the pump 6 and returned to the tank. At this time, when the main valve 20 is rapidly switched, the fluid in the flow paths 15a and 15b is rapidly compressed,
It causes a big shock. Therefore, in order to ensure a good ride comfort of the elevator, it is desirable to gently switch the main valve 20. The acceleration of the motor,
Rated speed drive, deceleration. When the car is stopped, the car also undergoes acceleration, rated speed travel, and deceleration, and then stops. After that, if the signal to the pilot valve 21 is released, the main valve 20 will also return,
Return to the initial state.

The relief valve 4 is provided to protect the fluid pressure device and prevents the fluid pressure from becoming an abnormally high pressure. Further, it operates together with the pilot valve 13 and the throttle valve 14 to perform the unload operation. The check valve 5 prevents the flow passage 15 from becoming a vacuum when the pilot operated check valve 2 and the fluid pressure pump 6 are out of synchronism with each other during the lowering operation. That is, when the flow path 15 becomes low in pressure, the fluid is sucked into the flow path 15 from the tank 9 through the flow path 16.

Regardless of the fluid flow direction, the overspeed prevention valve 3 switches the main valve 30 and switches the main valve 30 when the pressure drop amount at the main valve 30 and the throttle 31 exceeds a specified value, that is, when a flow rate exceeds the specified value.
Is cut off and the flow path 15a is connected to the flow path 16. As a result, the inflow / outflow of the fluid to / from the fluid pressure cylinder 1 is stopped, and the fluid discharged from the pump 6 is returned to the tank 9. When rising and falling, it operates as follows.

When rising, the liquid flows from the pump 6 to the fluid pressure cylinder through the main valve 30, the throttle valve 31, and the pilot operated check valve 2 of the overspeed prevention valve 3. If the pressure drop amount (Pa-Pb) of the main valve 30 and throttle 31 at this time is larger than the specified value, the pilot valves 34, 35
Is in the illustrated state. However, Pa is the pressure of the flow path 15a, Pb
Is the pressure in the flow path 15b. Then, Pa acts on the pressure receiving portion 33a of the main valve 30 described later with reference to FIG. 17, and Pa acts on the pressure receiving portion 33b.
Since Pb acts (Pa> Pb), the main valve 30 switches against the force of the spring 33c, shuts off the flow passage 15b, and connects the flow passage 15a to the flow passage 16. As a result, the supply of fluid to the fluid pressure cylinder 1 is stopped, and the fluid discharged from the pump 6 returns to the tank 9.

When descending, the fluid flows from the fluid pressure cylinder 1 to the pump 6 via the pilot operated check valve 2, the throttle 31 of the overspeed prevention valve 3 and the main valve 30. At this time, the pressure drop amount of the throttle valve 31 and the main valve 30 (Pa
-Pb) is larger than the specified value, the pilot valves 34, 35 are switched from the illustrated state, Pb acts on the pressure receiving portion 33a of the main valve 30, and Pa acts on the pressure receiving portion 33b (Pb> Pa). The main valve 30 is switched in the same manner as when rising. Therefore, the discharge of the fluid from the fluid pressure cylinder 1 is stopped as in the case of rising.

FIG. 16 shows the structure of an embodiment of the pilot operated check valve 2. The main valve 20 has a valve body 22, a valve body 23, a spring 23c, and a stopper 25a as main constituent elements, and its ports 22b, 22c.
Are connected to the flow paths 15b and 15c, respectively. The valve body 23 has an eufis 23b in the skirt portion 23a, and its displacement is limited by the stopper 25a. The pilot valve 21 has a valve body 26 and a valve body.
27 and solenoid 28 as main components, and its port 26
The a, 26b and 26c are connected to the port 22c, the fluid chamber 22e of the main valve 20 and the tank 9, respectively. Normally, the ports 26a and 26b are communicated with each other, and the high-pressure fluid at the port 22c is introduced into the fluid chamber 22e so that the valve body
23 is held in the position shown. Solenoid on command
When 28 is excited, valve 27 is driven and ports 26a and 26b
Is closed, the ports 26b and 26c are communicated with each other, and the fluid chamber 23e is opened to the tank 9. As a result, the valve body 23 operates against the force of the spring 23c by the fluid pressure acting on the fluid chamber 22d, thereby connecting the ports 22c and 22b. When raising the elevator, the fluid discharged from the fluid pressure pump 6 is the port 22b (flow path 15b).
From the port to the port 22c (fluid 15c) (free flow),
Push up the fluid pressure cylinder 1. When lowering, the solenoid 28 is excited by the lowering signal and the port 22 of the main valve 20 is energized.
By communicating with c and 22b, the high pressure fluid of the fluid pressure cylinder 1 is discharged by the fluid pressure pump 6, and the fluid pressure cylinder 1 is lowered. When the descent is complete, the solenoid is de-energized,
High-pressure fluid is introduced into the fluid chamber 22e, and the main valve 20 returns to the illustrated state. At this time, the throttle valve 29 controls the operating speed of the valve body 23, and the orifice 23b provided in the skirt 23a is connected to the ports 22c and 2c.
The opening area between 2b and 2b is gradually increased. The orifice 23b and the diaphragm 29 prevent the occurrence of an elevator start shock.

FIG. 17 is a diagram showing an example of the structure of the overspeed prevention valve 3, FIG. 18 is an enlarged view of the pilot valve 33, and FIG. 19 is an enlarged view of the pilot valve 34. The throttle 31 adjusts the flow passage area with a baffle plate or the like according to the flow rate. The main valve 30 is composed of a valve body 32, a valve body 33, and a spring 33c, and has fluid chambers 30d, 30e, 30f and ports 30a, 30b, 30c connected to the respective fluid chambers, and each port is a flow passage 15a, 15b. , 16 (Tank 9). The valve body 33 is a pressure receiving part
33a and 33b, and receive pressure from pilot valves 34 and 35, respectively. The pilot valves 34, 35 are two-position three-way switching valves, and have valve bodies 38, 39 provided with grooves or portions 38a, 38b, 39a that perform the same function, and fluid is supplied depending on the operating position of the valve bodies 38, 39. Switch. The end surface receives the pressure of the ports 30a, 30b through the flow paths 37a, 37d and 37b, 37e. Port 30a pressure Pa
Is greater than the pressure Pb at port 30b (Pa <Pb), valve body 3
8 and 39 are in the state shown in the figure, connecting the flow paths 37a and 37c, 37e and 37f, and blocking the flow paths 37b and 37d. In the opposite case (Pa <Pb), the valve bodies 38, 39 are in the opposite positions to those shown in the figure, and the flow paths 37b, 37c, 37
Connect d and 37f, and cut off 37a and 37e. That is, the high pressure side of the ports 30a and 30b is connected to the pressure receiving portion 36a of the main valve body 36, and the low pressure side is connected to the pressure receiving portion 26b. Therefore, the valve body 36 is
A force corresponding to the pressure difference between 0a and 30b is received in the right direction. When this force becomes larger than the specified value, the valve element 33 moves against the spring 30c in the direction of closing the flow path. Due to the operation of the valve element 33, the pressure difference between the ports 30a and 30b is further increased, which promotes the operation of the valve element. That is, if the throttle 31 is adjusted according to the flow rate of the overspeed prevention valve 3, when the flow rate of a set value or more flows, the main valve 30 operates to shut off the port 30b, and the ports 30a and 30c. To communicate. This means that the discharge fluid of the pump is returned to the tank and the flow path to the fluid pressure cylinder 1 is closed when the elevator is rising, and it flows out from the fluid pressure cylinder 1 when the elevator is descending. This is to shut off the fluid, and in either case, the car 10 can be stopped safely without increasing the speed higher than the specified speed.

FIG. 20 shows an example of the structure of the relief valve 4 which also serves as an unload valve. The relief valve 4 includes a valve body 40 and a valve body.
41 and pilot valve 43 and unload pressure setting pilot valve
44 is the main component. The valve body 41 is a poppet type having a shaft 41a and forms fluid chambers 40c (back surface of the poppet), 40d (shaft end surface) and 40e (side surface of the poppet) between the valve body 40 and the valve body 40. The fluid chamber 40c communicates with the port 40a via the throttle 45, and communicates with the fluid chamber 40d via the throttle 48. Port 4
0a and 40b are connected to the flow paths 15a and 16, respectively. The pilot valve 43 communicates with the fluid chamber 40c, and has a valve body 43a, a spring 43b, and a screw 43c.
The pressure of the spring 43b is adjusted and the fluid chamber 40c
Set the relief pressure of. The other pilot valve 44 is a fluid chamber
It is in communication with 40d and consists of a valve element 44a, a spring 44b and a solenoid 44c and is normally closed. However, when the solenoid 44c is excited, the fluid chamber 40d is opened to the atmosphere.

In the relief valve 4, the force exerted on the valve body 46 from the fluid chambers 40c, 40d at normal times is larger than the force exerted on 40e, and the ports 40a and 40b are shut off as shown in the figure (the port 40b is connected to the tank pressure). ). When the pressure of the port 40a becomes larger than the pressure set by the pilot valve 43, the pilot valve 43 is opened, the fluid in the fluid chambers 40c and 40d is discharged, and the poppet 41 is moved to the spring 41b.
Displaced against, and flow the fluid from port 40a to 40b,
Do not raise the pressure at port 40a any further.

When the relief valve 4 is operated as an unload valve, the pilot valve 44 is excited to open the fluid chamber 40d to the tank 9, and the force acting on the back surface of the poppet 41 is reduced by the cross-sectional integral of the shaft 41a. The main valve opens at a pressure lower than the relief pressure in the port 40a. This pressure is the unload pressure, and the difference between the relief pressure and the unload pressure is determined by the size of the shaft 41a.
That is, the unload pressure is always set smaller than the relief pressure by a constant value regardless of the set value of the relief pressure. It will stop safely without increasing the speed above the specified speed.

FIG. 21 is a sectional view showing the structure of another embodiment of the relief valve. The same symbols as in FIG. 20 represent the parts that perform the same functions.
The relief pressure is set in the same manner as in the embodiment shown in FIG. 20, and is set by the pilot valve 43. However, the setting of unload pressure is different. When the pilot valve 13 is excited, the fluid in the fluid chamber 40c is released to the tank through the pilot valve 44 and the throttle 46. Therefore, the unload pressure is set by adjusting the two throttles 45 and 46.

The overspeed check valve 3 shown in FIG. 12 can also be used in the embodiment shown in FIG. The overspeed check valve 3 in FIG. 12 has the same structure as the overspeed check valve shown in FIG. 17, but also has the function of a check valve (suction valve) 5 for protecting the pump. That is, the point different from the embodiment of FIG. 17 is that the valve element 33 is divided into 33d and 33e, and the spring 33f is added. The valve elements 33d and 3
3e and 3e operate integrally, and are similar to the case described in FIG. The spring 33f prevents the two valve bodies 33d and 33e from operating separately in the normal state.

The function as a suction valve is that when the port 30a communicating with the fluid pressure pump 6 has a lower pressure than the port 30c communicating with the tank 9, the port 30b has the same pressure as or higher than the port 30a. The valve bodies 38, 39 of the valve are located below, and the flow paths 37c, 37f communicate with 37b, 37d, respectively. Therefore, a force from the left acts on the valve element 33e, and is further pushed to the right by the pressure acting on the left end face (fluid chamber 30f),
Fluid is supplied from the tank 9 to the fluid pressure pump 6 by connecting the ports 30c and 30a. This is the action itself of the suction valve 5.

〔The invention's effect〕

 According to the present invention, the following effects can be obtained.

(1) Since the pilot operated check valve for holding the position of the car is gradually switched, the pressure in the flow path between the check valve and the fluid pressure pump slowly rises when the elevator is started to descend. The surge pressure is prevented from occurring and smooth downward acceleration characteristics are obtained.

(2) The structure is such that the pilot fluid pressure is supplied by the excitation of the pilot valve to operate the main valve of the control valve, and the excitation is released to restore the main valve, so if the control command is interrupted in the event of an abnormality such as a power failure. The main valve quickly shuts off the flow path and prevents the car from descending at high speed.

(3) Regardless of the operating direction of the car, if the flow rate of the fluid passing through the overspeed protection valve exceeds the specified value, the overspeed protection valve operates, and if the elevator rises, the pump discharge flow rate is returned to the tank. , Shuts off the flow path between the fluid pressure cylinder and the fluid pressure pump, shuts off the flow from the fluid pressure cylinder when the elevator is descending, and in either case, safely stops the elevator car.

(4) In the relief valve of the present invention, of course, the relief valve main body operates, but the pilot valve can be switched to act as an unload valve, and the fluid is heated by the unload operation to control the temperature of the fluid. It also becomes possible.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the fluid pressure elevator according to the present invention, FIG. 2 is a circuit diagram showing another embodiment of the fluid pressure elevator according to the present invention, and FIG. 3 is a control valve according to the present invention. FIG. 4 is a diagram showing the structure of an embodiment, FIG. 4 is a diagram for explaining the operation of FIG. 3 embodiment, FIG. 5 is a diagram showing the structure of another embodiment of the control valve, and FIG. 6 is still another of the control valve. FIG. 7 is a diagram showing the structure of another embodiment of FIG. 7, FIG. 7 is a diagram showing the structure of another embodiment of the control valve, FIG.
FIG. 9 is a diagram showing the structure of yet another embodiment of the control valve, FIG. 9 is a diagram showing the structure of another embodiment of the control valve, and FIG. 10 is a diagram showing one embodiment of the overspeed prevention valve according to the present invention. Figure showing structure, No. 11
FIG. 12 is a view showing the structure of another embodiment of the overspeed protection valve according to the present invention, and FIG. 12 is a view showing a more specific structure of the overspeed protection valve,
FIG. 13 is a diagram showing the structure of an embodiment of a relief valve with an unloading function, FIG. 14 is a diagram showing the structure of another embodiment of a relief valve with an unloading function, and FIG. 15 is a fluid pressure according to the present invention. FIG. 16 is a circuit diagram showing another embodiment of the elevator, FIG. 16 is a diagram showing the structure of a pilot operated check valve, FIG. 17 is a diagram showing the structure of an overspeed check valve, and FIGS. 18 and 19 are overspeed. FIG. 20 is a diagram showing a structure of a pilot valve of the prevention valve, FIG. 20 is a diagram showing a structure of a relief valve which also serves as an unload valve, and FIG. 21 is a diagram showing a structure of another relief valve. DESCRIPTION OF SYMBOLS 1 ... Fluid pressure cylinder, 2 ... Control valve (pilot operated check valve with flow rate control function), 3 ... Overspeed prevention valve, 4 ... Relief valve with unload function, 5 ... Suction valve (check valve), 6 ... fluid pressure pump, 7 ... motor, 8 ... filter,
9 ... Fluid tank, 10 ... Car, 11 ... Inverter, 12 ...
Elevator control device, 13 ... Pilot valve, 15, 16, 17 ... Flow path, 20 ... Control valve main valve, 21 ... Pilot valve, 22 ... Control valve body, 23 ... Skirt part, 24 ... Piston, 25 ... Stopper, 30
… Overspeed check valve main valve, 31… Throttle valve, 32… Overspeed check valve body,
33 ... Valve body, 34, 35 ... Pilot valve, 40 ... Relief valve body, 41 ... Valve body, 42 ... Restrictor, 43 ... Pilot valve, 44 ... Unload pressure setting pilot valve, 45 ... Stopper, 46 ... Pilot valve Body, 47 ... Valve, 48 ... Throttle.

Front Page Continuation (72) Inventor Tadahiko Nogami 502 Jinritsu-cho, Tsuchiura-shi, Ibaraki Machinery Research Laboratories, Ltd. (72) Inventor Yoshimichi Akasaka 502 Jin-machi, Tsuchiura-shi, Ibaraki Machinery Research Co., Ltd. In-house (72) Inventor Eiichi Sasaki 1070, Moe, Katsuta-shi, Ibaraki Hitachi, Ltd. Mito Plant (56) Reference JP-A-64-34879 (JP, A)

Claims (6)

[Claims] 1. A control system for controlling the number of revolutions of a fluid pressure pump to control the flow rate of fluid supplied to or discharged from the fluid pressure cylinder, and to directly or indirectly drive a car with the fluid pressure cylinder. In a fluid pressure elevator for raising or lowering, a pilot operated check valve of a type between the fluid pressure pump and the fluid pressure cylinder, which discharges pilot pressure fluid when the pilot valve is de-energized to close the main valve. The valve opening degree when the fluid flows in the reverse direction is regulated to be smaller than the valve opening degree when the fluid flows in the reverse direction, and the force that always closes the valve when the fluid flows in the reverse direction. A fluid pressure elevator comprising a valve body stopper that causes the valve body to act on the valve body. 2. The fluid pressure elevator according to claim 1, further comprising a skirt portion formed with an orifice that gradually increases or decreases the opening area of the check valve in accordance with the operation of the valve body of the check valve. A fluid pressure elevator provided on the valve body of the check valve. 3. The fluid pressure elevator according to claim 1, wherein the check valve is gradually opened so that the fluid pressure between the fluid pressure cylinder and the fluid pressure pump is substantially balanced with the pressure of the fluid pressure cylinder. In addition, after that, the fluid pressure elevator is provided with a control means for activating the fluid pressure pump and lowering the car. 4. A fluid pressure elevator according to any one of claims 1 to 3, wherein a piston that opens the check valve so that the fluid flows in a reverse direction according to a control command, and a valve body that controls the flow of the fluid. Is relatively slidably fitted to each other, and when the fluid flows in the forward direction, only the valve body moves. 5. The flow rate of fluid supplied to or discharged from the fluid pressure cylinder is controlled by controlling the rotational speed of the fluid pressure pump, and the car is directly or indirectly driven by the fluid pressure cylinder. In a fluid pressure elevator that raises or lowers, the discharge fluid of the fluid pressure pump is fluidized when the outlet pressure of the fluid pressure pump becomes a predetermined value or more in a channel branched from the channel connecting the fluid pressure pump and the fluid pressure cylinder. A relief valve for discharging to a tank is arranged, a shaft is provided on a valve body of the relief valve, and one of the valve body and the shaft is controlled by pressure from a pilot relief valve to control the other of the valve body and the shaft. A fluid pressure elevator characterized in that a relief pressure and an unload pressure can be set in the relief valve by controlling the pressure from a pilot switching valve. 6. A fluid pressure elevator according to claim 5, wherein a pilot chamber is connected to a pilot relief valve and a pilot switching valve, and when the pilot switching valve is excited, the valve element of the relief valve is mechanically positioned. A fluid pressure elevator characterized in that a relief pressure and an unload pressure can be set in the relief valve by providing a stopper for restricting the pressure on the relief valve.