JPH04121373A - Fluid pressure elevator - Google Patents

Abstract

PURPOSE:To obtain a comfortable ride feeling while realizing a fixed speed characteristic by arranging a pilot operating check valve of type, in which a main valve is closed by discharging pilot pressure fluid when energization of a pilot valve is released, between a liquid pressure pump and a fluid pressure cylinder. CONSTITUTION:Pilot valves 21a, 21b of a control valve 2 are actuated based on a down-command from a control unit 12 to slowly switch a main valve 20, and a fluid pressure cylinder 1 communicates with a fluid pressure pump 6 to balance pressures of flow paths 15a, 15c. Thereafter, a motor 7 is started and accelerated according to a speed signal to return high pressure fluid in the fluid pressure cylinder 1 to a tank 9 by the pump 6. Accordingly, the fluid pressure cylinder 1 and a riding cage 10 are started to perform down-operation and accelerated. The motor 7 is accelerated, driven at a rated speed, decelerated and stopped to stop also the riding cage 10 via a process of acceleration, rated speed running and deceleration. And then, the initial condition is restored by resetting also the main valve 20 when a signal to the pilot valves 21a, 21b is released.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a hydraulic elevator, and more particularly to a method for controlling the flow rate of fluid supplied to or discharged from a hydraulic cylinder to increase the speed of the hydraulic cylinder. The present invention relates to a hydraulic elevator of a type that controls the speed of a car supported directly or indirectly by a cylinder.

[Conventional technology]

In a hydraulic elevator that controls the pressure fluid to control the speed of the hydraulic cylinder and the speed of the car,
A method of controlling pressure fluid using a flow control valve in response to a speed command, and a method of controlling pressure fluid by controlling the rotational speed of a fluid pressure pump using a motor are known. In particular, with advances in electronic control devices and control technology, it has become easier to control the rotational speed of the motor using an inverter, making it more practical for fluid pressure elevators to directly control the rotational speed of the fluid pressure pump with the motor. .

Incidentally, an example of this type of conventional technology is Japanese Patent Application Laid-open No. 57
-81073, JP-A No. 60-57471, etc.

In a method that controls the speed of the car by controlling the motor rotation speed, if the rotation speed exceeds the rated value due to a failure of the control device, etc., the car may rise or fall beyond the rated speed. . Furthermore, if the driving power becomes zero due to a power outage or the like, the one-person car will be in a free fall state, and it is possible that it will descend beyond the safe speed. It is essential to ensure safety even in such an emergency.

[Problem to be solved by the invention]

For hydraulic elevators that control the speed of the car by controlling the rotational speed of the motor, the direction of operation.

Due to changes in the number of passengers and fluid temperature, changes in acceleration at startup become large, reducing ride comfort.

The rate of rise or fall of the car may be greater than permissible. That is, when the check valve for maintaining the position of the car is opened at startup, the fluid is rapidly compressed due to the pressure difference before and after the valve, resulting in large acceleration fluctuations. Furthermore, if the pump is driven at a speed higher than its rated speed due to an abnormality in the control device, or if the driving power is lost due to a power outage, there is a possibility that the pump will run at a speed higher than the allowable speed.

The purpose of the present invention is to realize constant speed characteristics regardless of the operating direction of the elevator, the number of passengers, or the fluid temperature.
It is an object of the present invention to provide a fluid pressure elevator which can obtain good speed characteristics, that is, good riding comfort by quickly reducing the car speed of an elevator even in an emergency, and is highly safe and reliable.

[Means to solve the problem]

The above purpose is to develop a control valve or control valve that improves the structure and control method of a pilot-operated check valve that is normally used between a fluid pressure pump and a fluid pressure cylinder to maintain the position of a car. This is achieved by arranging prevention valves and providing these valves with the ability to control the flow rate at the initial stage of startup and the function of limiting the maximum flow rate. Here, the initial startup control capability refers to the ability to start the motor according to the startup command and control the control valve to ensure smooth startup, while also automatically controlling the control valve when the power source stops in case of an emergency such as a power outage. This is the ability to reduce the flow rate of pressure fluid flowing out from the hydraulic cylinder and decelerate and stop the single-car. In addition, the maximum flow rate limiting function takes advantage of the fact that when the fluid flowing through a control valve exceeds a specified flow rate, the pressure drop at the control valve or overspeed prevention valve increases beyond the specified value. This function narrows the opening area of the valve and limits the flow rate, or directly closes 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 fluid supplied to or discharged from a fluid pressure cylinder by controlling the rotational speed of a fluid pressure pump. Or, in a fluid pressure elevator that indirectly raises or lowers a car, a type is provided between a fluid pressure pump and a fluid pressure cylinder that discharges pilot pressure fluid and closes the main valve when the pilot valve is deenergized. This paper proposes a hydraulic elevator equipped with a pilot-operated check valve.

The valve body of the check valve may be provided with a skirt portion formed with an orifice that gradually increases or decreases the opening area of the check valve as the check valve body operates.

The control means gradually opens a check valve to substantially balance the fluid pressure between the fluid pressure cylinder and the fluid pressure pump with the pressure of the fluid pressure cylinder, and then starts the fluid pressure pump to lower the car. It is desirable to have the following.

In either case, the valve opening when fluid flows in the reverse direction is regulated to be smaller than the valve opening when fluid flows in the forward direction, and when fluid flows in the reverse direction, the force is always in the direction of closing the valve. It is also possible to provide a stopper for the valve body that acts on the valve body.

Further, a piston that opens the check valve so that the fluid flows in the reverse direction according to a 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, the valve body It can also be configured so that only the body moves.

In order to achieve the above object, the present invention also arranges a throttle valve and a control valve between a fluid pressure cylinder and a fluid pressure pump, and operates the control valve by a pressure difference before and after the throttle valve and the control valve. The flow path between the fluid pressure cylinder and fluid pressure pump is blocked to decelerate the car.

This paper proposes a hydraulic elevator with a stop valve.

In either case, a throttle valve and a control valve are arranged between the fluid pressure cylinder and the fluid pressure pump, and the control valve is operated by the pressure difference before and after the throttle valve and the control valve. It is possible to use a valve to decelerate and stop the car by blocking the flow path between the two.

The control valve operates by always receiving the higher fluid pressure of the fluid pressure cylinder and the fluid pressure pump on one side, and shuts off the fluid pressure cylinder and the fluid pressure pump, so that the fluid pressure pump is connected to the fluid tank. It is a valve that communicates with the

A fluid in which a relief valve is provided in a flow path branching from a flow path connecting a fluid pressure pump and a fluid pressure cylinder to discharge fluid discharged from the fluid pressure pump into a fluid tank when the outlet pressure of the fluid pressure pump exceeds a predetermined value. It can also be a pressure elevator.

A relief valve is provided in a flow path branching from the flow path connecting the fluid pressure pump and the fluid pressure cylinder to discharge fluid discharged from the fluid pressure pump into a fluid tank when the outlet force of the fluid pressure pump exceeds a predetermined value. is also possible.

A shaft is provided on the valve body of the relief valve, one of the valve body and the shaft is controlled by the pressure from the pilot relief valve, and the other of the valve body and the shaft is controlled by the pressure from the pilot switching valve. It is also desirable to be able to set the relief pressure and unload pressure.

The pilot chamber is connected to the pilot relief valve and the pilot switching valve, and a stopper is provided to mechanically restrict the position of the valve body of the relief valve when the pilot switching valve is excited, and relief pressure and unload pressure are applied to the relief valve. Make it configurable.

Further, in order to achieve the above object, the present invention disposes a throttle valve and a control valve between the fluid pressure cylinder and the fluid pressure pump, and operates the control valve by the pressure difference before and after the throttle valve and the control valve. The present invention proposes a fluid pressure elevator in which a valve is used to shut off a flow path to a fluid pressure cylinder and discharge fluid discharged from a fluid pressure pump into a fluid tank.

In this case as well, a pilot-operated check valve is placed between the fluid pressure pump and the fluid pressure cylinder, and the opening area of the check valve is gradually increased or decreased as the valve body of the check valve operates. It is possible to provide the valve body of the check valve with a skirt portion in which an orifice is formed.

The valve body is divided into a valve body that switches the direction of fluid flow at the same time it receives pilot pressure, and a valve body that receives pilot pressure. The valve body operates integrally to block the flow path between the fluid pressure pump and the fluid pressure cylinder, while separating into individual valve bodies that operate to regulate the flow rate when the flow rate exceeds a predetermined value. .

A relief valve is provided in a flow path branching from a flow path connecting the fluid pressure pump and the fluid pressure cylinder to discharge fluid discharged from the fluid pressure pump into a fluid tank when the outlet pressure of the fluid pressure pump exceeds a predetermined value.

In addition, a shaft is provided on the valve body of the relief valve, one of the valve body and the shaft is controlled by the pressure from the pilot relief valve, and the other of the valve body and the shaft is controlled by the pressure from the pilot switching valve. To enable setting of relief pressure and unload pressure on a valve.

In either case, the pilot chamber is connected to the pilot relief valve and the pilot switching valve, and a stopper is provided to mechanically restrict the position of the relief valve's valve body when the pilot switching valve is energized. The unloading pressure can be set.

[Effect]

In the present invention, the motor, ie, the pump, is started after the fluid pressures before and after the startup control valve are balanced, so that smooth operation is possible and the riding comfort of the elevator is improved.

Further, a flow control valve or a combination of a flow control valve and a throttle valve is disposed between the fluid pressure pump and the fluid pressure cylinder.

When the flow rate of fluid flowing through the control valve or throttle valve exceeds a specified value, the pressure drop at the flow rate control valve or throttle valve also increases beyond the specified value. In the present invention, this pressure drop is utilized to operate the control valve, automatically narrowing the opening area of the flow control valve, and restricting the flow rate through the control valve. The flow direction of the fluid flowing through the control valve changes in response to the rise or fall of the elevator, but in the present invention, the control valve is changed in the same manner regardless of the fluid flow direction in response only to the pressure drop across the control valve. make it work. Therefore, regardless of the driving direction of the car, the control valve operates only in response to the fluid pressure loss caused by the fluid flowing through the control valve or the control valve and throttle valve combination, and the flow rate of the fluid flowing through the control valve increases. limited. As a result, the car speed of the elevator is limited to a specified value or less and the car is stopped safely, thereby ensuring the safety and reliability of the elevator.

〔Example〕

FIG. 1 is a fluid pressure circuit diagram showing an embodiment of a fluid pressure elevator according to the present invention. In FIG. 1, 1 indicates a car 10.
2 is a control valve (here, a pilot-operated check valve with a flow rate control function), 4 is a relief valve with an unloading function, and 5 is a pump protection 6 is a fluid pressure pump capable of forward and reverse rotation, 7 is a motor, 8 is a filter, and 9 is a fluid tank. 11 is an inverter that drives the motor 7, 12 is an elevator control device, 13 is a pilot valve, and 15, 16, and 17 are flow paths.

The control valve 2 includes a main valve 20 and a pilot valve 21a.

21b, which normally allows flow to the fluid pressure cylinder 1 as shown in the figure, and blocks flow in the opposite direction. pilot valve 21a,
When a command is input to 21b, the main valve 20 is opened and fluid can be discharged from the hydraulic cylinder 1. Although the pilot valves 21a and 21b are ON-OFF valves here, the same effect can be obtained with a 2nd position 3-way valve, and the circuit is not limited to the illustrated circuit.

The relief valve 4 is provided for unloading operation to control the fluid temperature and for protection of the circuit, and the suction valve 5 is provided for the flow path 1.
This is provided to prevent 5a from becoming a vacuum.

In this embodiment having such a configuration, a case where the seat heel 10 is raised and a case where it is lowered will be explained.

(1) When ascending, the inverter 11
(to start the motor 7, the direction of rotation at this time is forward rotation), accelerate to the rated rotational speed according to the speed signal, and drive. The fluid passes through the filter 8, is pressurized by the fluid pressure pump 6, increases in proportion to the pump rotation speed which is proportional to the speed signal, passes through the control valve 2 which acts as a check valve, and is supplied to the fluid pressure cylinder 1. .

As a result, the hydraulic cylinder 1 that directly or indirectly drives the seat 10 is activated, and is gradually accelerated to the rated speed in proportion to the speed signal (motor rotational speed). On the other hand, if the rotation speed of the motor 7 is reduced by the deceleration signal (speed signal), the rotation speed of the fluid pressure cylinder 1 (car 1
0) decelerates and finally comes to a stop. Even if the command is subsequently released, the control valve 2 closes and maintains the position of the car seat 1.

At this time, due to some abnormality, the outlet pressure of the pump 6 is set to the specified value (
When the pressure exceeds the relief pressure (relief pressure), the relief valve 4 acts to discharge fluid discharged from the pump 6 to the tank 9, preventing an abnormal pressure rise in the fluid pressure circuit and preventing damage to equipment and piping.

(2) At the time of descent, the pilot valves 21a and 21b of the control valve 2 are operated based on the descent command from the control device 12, and the main valve 20 is gently operated.
is switched, the fluid pressure cylinder 1 and the fluid pressure pump 6 are communicated with each other, and 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 rotation (reverse rotation), accelerates according to the speed signal, and returns the high pressure fluid in the fluid pressure cylinder 1 to the tank 9 by the pump 6. Therefore, the fluid pressure cylinder 1 and the car 10 are lowered. activated and accelerated.

In this way, the pump is started after the fluid in the flow path between the control valve 2 and the pump 6 is balanced with the fluid in the cylinder 1, so smooth startup is possible during downward startup.
There is no starting blemish, and just like when ascending, motor 7 accelerates, drives at rated speed, decelerates, and stops. After that, if the signals to the pilot valves 21a and 21b are released,
The main valve 20 also returns to its initial state.

If the main valve 20 is suddenly switched at the time of starting the descent.

Since the fluid in the flow path 15a is rapidly compressed, a large shock occurs. Therefore, in order to ensure a good ride comfort in the elevator, it is preferable to switch the main valve 20 gently.
It is even better to use a PWMlf-driven valve or a valve that operates in proportion to the command as b.

At this time, an imbalance occurs between the opening operation of the control valve 2 and the starting operation of the motor 7, and the suction flow rate of the pump 6 is reduced to the cylinder 1.
It is conceivable that the flow rate will be larger than the exhaust flow rate of the pump, but in that case, fluid will be replenished from the tank 9 via the suction valve 5, and the circuit 15a will become vacuum, causing cavitation and damaging the pump 6. prevent.

(3) When the driving power is lost due to an emergency power outage or the like, the ride heel 10 begins to fall due to its own weight at a speed exceeding the allowable speed, which is inconvenient for safety. In such a case, since the control command is canceled, the pilot valves 21a and 21b are de-energized and return to the reference position (the state shown in the figure), and the main valve 20 quickly returns to the state shown in the figure. Therefore, the flow of fluid from the hydraulic cylinder 1 is cut off and the car 10 is decelerated and stopped, thereby dramatically improving safety. Even in an emergency other than a power outage, the elevator can be stopped in the same way by canceling the pilot valve control signal. An example of this is
Possible causes include overspeed descent due to an abnormality in the control device or damage to the coupling between the pump and motor.

FIG. 2 is a fluid pressure circuit diagram showing another embodiment of the present invention. The same symbols as in FIG. 1 indicate parts that have the same function. The difference from the embodiment shown in 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 includes a main valve 30 and a throttle valve 31, and operates when the flow rate of fluid flowing through the valve 3 on the downward side exceeds a specified value. In other words, if the flow rate through this valve exceeds the specified value,
When the pressure difference across the valve becomes large, the main valve 30 operates due to this pressure difference, and the circuit is immediately cut off to stop the ride and heel 10. In this way, in addition to power outages, acceleration due to control device malfunctions can be prevented, improving safety.

FIG. 3 is a sectional view showing the structure of one embodiment of the control valve 2. As shown in FIG. The main valve 20 has a valve main body 22, a valve body 23, a spring 20c, a piston 24, and a stopper 25 as main components, and the boats 22a and 22b have flow paths 15a (15b) and 15, respectively.
connected to c.

The valve body 23 has an orifice 23b in its skirt portion 23a, and the valve body 2 is guided by the skirt portion 23a and the shaft 23c.
2 and is pressed against the valve seat by a spring 20c. The piston 24 is driven by pilot valves 21a and 21b, and drives the valve body 23. The movement range of the piston 24 is limited by a stopper 25.

When excited, the pilot valves 21a, 21b supply pilot fluid to or discharge pilot fluid from the piston chamber 22f. Normally, the piston chamber 22f is open to the tank 9, but when the pilot valve 21a is energized, the throttle 22f is opened to the tank 9.
When the fluid chamber 22d and the piston chamber 22f are connected via 1c and the pilot valve 22b is excited, the fluid chamber 22 is isolated from the tank 9.

(1) The rising operation control valve 2 simply acts as a check valve, and the hydraulic pump 6
The discharge fluid is from port 22a (flow path 15a or 15b)
This becomes a flow (free flow) from the water to the boat 22b (channel 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 spring 20c is set so that the valve body 23 is sufficiently opened.

(2) Lowering operation The pilot valves 21a and 21b are excited by the lowering signal to supply high pressure fluid to the piston chamber 22f, and the piston 24 is pushed to displace the main valve body 23.

The ports 22a and 22b are communicated with each other, and the fluid pressure cylinder 1
The high-pressure fluid is discharged by the fluid pressure pump 6, and the fluid pressure cylinder 1 and the cage 10 are lowered.

At this time, the throttle 21c controls the operating speed of the valve body 23, and the orifice 23b provided in the skirt 23a gradually increases the opening area between the boats 22b and 22a. The orifice 23b and the throttle 21c prevent the occurrence of elevator startup shock. The pilot valve may be configured with a proportional solenoid valve or a PWM control valve that operates in proportion to a command to control the pilot flow rate.

At this time, the stopper 25 limits the displacement of the piston 24, ie, the opening degree of the main valve 20, to provide a constant pressure drop to the flow from the port 22b to the port 22a. In this way, if the driving power is lost due to a power outage, etc., the main valve 2o will automatically close due to the pressure difference behind the valve cylinder, reducing the discharge flow rate from the cylinder 1, decelerating and stopping the single car 10, and improving safety. Improve.

When the lowering is completed, the pilot valve is de-energized, the high pressure fluid in the piston chamber 22f is discharged, the main valve body 23 is returned to the state shown, 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 explained in detail using FIG. 4. This figure shows the movement of the main valve body 23 and the pressure in the port 22a during the ascending and descending operations.

(1) When rising (broken line) When the pump 6 is started, the pressure of the port 22a increases with the discharged fluid, and when the pressure exceeds the cylinder pressure, the fluid pushes against the valve body 23 against the force of the weak spring 20c of the main valve 20. It is pushed open and flows into port 22b (communicating with cylinder 1). When the pump rotation speed increases from acceleration to full speed according to the command,
The flow rate flowing through this valve also increases, and the displacement of the main valve body 2''3 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 equal to the flow rate flowing through this valve. Pu (differential pressure ΔPu) is almost constant regardless of the cylinder pressure and is slightly larger than the cylinder pressure.This is because the main valve 20
This is because it acts as a check valve with low cracking pressure.

When the flow rate of the pump 6 decreases and the ride 10 decelerates and stops, the valve body 23 is displaced and closed in approximately proportion to the flow rate. During this time, the pressure in port 22a remains approximately constant as shown, for the reasons described above.

When the main valve 20 closes, the pressure in the port 22a drops rapidly due to fluid leakage from the pump 6. That is, the valve body 23 is displaced approximately in proportion to the flow rate.

As shown in the figure, acceleration, full speed, and deceleration are clearly visible, but
The pressure in the port 22a is approximately constant while the elevator is running.

(2) When descending (solid line) When the pilot valves 21a and 21b are excited and the piston 24 displaces the valve body 23, the port 22a becomes the port 2.
2b, and the pressure increases.

Thereafter, the pump 8 is driven to accelerate the car 10 and make it run at full speed. The main valve 20 is fully opened slightly earlier than the rotation of the pump 6, but the degree of opening at this time is smaller than when the valve is raised, as described above. Therefore, the difference between the pressure Pd of the port 22a and the cylinder pressure during the downward movement is ΔPd, which is greater than the differential pressure ΔPu during the upward movement.Thereafter, the pump rotation speed is decelerated in accordance with the command.

and the pilot valve 21a after the pump is stopped.

When 21b is de-energized, the main valve 20 also returns to its original state as shown in the figure, completing the lowering operation. The pressure difference ΔPd decreases when deceleration begins and becomes almost zero when the engine stops, and when the control valve 20 closes, the pressure Pu at the port 22a suddenly decreases.

(3) At the time of emergency stop (-dotted chain line) While the hydraulic elevator is running, it may come to an emergency stop for some reason. If the car 10 is rising at this time, the car will temporarily stop due to gravity, and then begin to descend, increasing the descending speed.

If it is descending, the descending speed will continue to increase.

In either case, safety is compromised.Therefore, in the control valve 2 of the present invention, excitation of the pilot valves 21a and 21b is released to discharge the fluid from the piston valve 22f, as shown by the dashed line in FIG. Pressure difference ΔP before and after the valve body 23 of the main valve 20
It is safe because the valve body 23 is forcibly closed by d, and the car 10 is decelerated and stopped.

As described above, according to the control valve of the present invention shown in FIG. 3, the valve can be raised, lowered, and stopped in an emergency manner, and a fluid pressure elevator with good riding comfort and high safety can be provided.

FIG. 5 is a sectional view showing the structure of another embodiment of the control valve 2. As shown in FIG. The same symbols as in FIG. 3 indicate parts with the same function.

This embodiment differs from the embodiment shown in FIG.
This is position 5. In the embodiment shown in FIG. 3, a stopper 25 was provided on the piston 24, but in the embodiment shown in FIG.
The displacement of 3 is directly limited. Since the operation and effect are the same as those shown in FIG. 3, the explanation will be omitted here.

FIG. 6 shows an embodiment similar to the embodiment in FIG. 3 or 4, but the valve body 23 is provided with a communication hole 23e that communicates the fluid chambers 22c and 22g, and the fluid pressure is the same as that of the fluid chamber 22c. This also acts on the fluid chamber 22g, reducing the force from the fluid acting on the valve body 23.

In this way, in the unlikely event that the valve body 23 is
Even if the pressure difference before and after is large, the force for driving the piston 24 can be small. This means that the pressure receiving area of the piston 24 that activates the valve body 23 is small, the flow rate flowing through the pilot valve is small, and the pilot valve may also be small. In this way, when the pilot valve becomes smaller,
This is advantageous because the fluid flow rate for driving the control valve can be saved and the startup shock is small as a hydraulic elevator.

In addition, when it is necessary to close the control valve rapidly, as in the case of an emergency described above, the flow rate of the fluid discharged from the fluid chamber 22f decreases, so the operation of the control valve becomes faster, which is preferable. .

Since the function of the control valve is the same as in the embodiment of FIG. 3 or 4, the explanation thereof will be omitted here. Figure 7 shows control valve 2
FIG. 7 is a sectional view showing still another embodiment of the invention. The same symbols as in FIGS. 3 and 4 indicate parts with the same function. This embodiment differs from the embodiments shown in FIGS. 3 and 4 in that the piston 24. This is the structure of the stopper 25. That is, the piston 24 is slidably provided on the shaft 23c of the valve body 23, and a stopper 23d prevents the piston from coming off. The piston 24 is a piston chamber 22e provided in a member 22c of the valve body 22.

It can slide within 22f, and its range of motion is limited by a stopper 25 while being pushed by a spring 24a.

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

(2) Lowering operation When descending, the pilot valve 21a is activated by command.

21b is energized to supply pilot fluid to the piston chamber 22f, the piston 24 is pulled up against the force and fluid pressure of the spring 20c (the valve body 23 is also pulled up), and the fluid pressure cylinder 1 and the fluid pressure pump 6 are gradually opened. The fluid in the cylinder 1 is discharged by the fluid pressure pump 6, and the seat 10 is started to descend and accelerated. Since the movement of the piston 24 is limited by the stopper 25, the position of the valve body 23 at this time is the maximum valve opening degree when descending, and a constant pressure difference is maintained in the flow from the port 22b to the port 22a. As explained in Figure 3, this pressure difference automatically causes the control valve 2 to open in the event of a power outage.
It becomes the force to close. When decelerating or stopping, the rotational speed of the pump 6 is reduced to reduce the discharge flow rate from the cylinder 1, and when the pump 6 is stopped, the excitation of the pilot valves 21a and 21b is canceled to discharge the fluid in the piston chamber 22f, and the piston 24 and valve The body 23 is returned to its original position.

In the event of an emergency such as a power outage, if the pilot valve 21.21b is de-energized as explained in FIG.
4a, 20c and the fluid chambers 22d, 22 before and after the valve body 23
The pressure difference between ports 22b and 22a immediately blocks the flow path from port 22b to port 22a. This causes the ride 10 to stop.

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

The same symbols as in FIG. 7 indicate parts with the same function. This embodiment differs from the embodiment shown in FIG. 7 in the stopper 25. In the embodiment shown in FIG. 7, only the amount of movement 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 operation and effect are the same as those of the embodiment shown in FIG. 7, the explanation thereof will be omitted here.

FIG. 9 shows an embodiment similar to the embodiment in FIG. 7 or 8, but the valve body 23 is provided with a communication hole 23e that communicates the fluid chambers 22c and 22g, so that the same fluid pressure as in the fluid chamber 22C is provided. It also acts on the fluid chamber 22g to reduce the force from the fluid acting on the valve body 23.

FIG. 10 is a sectional view showing the structure of one embodiment of the overspeed prevention valve 3. It consists of a main valve 30 and a throttle 31. The main valve 30 consists of a valve body 32, a valve body 33, and a spring 3°C, and includes fluid chambers 32c, 32d, and ports 32a and 32 connected to each fluid 1.
It has b. @31 is a baffle plate or the like that adjusts the flow path area according to the flow rate. The valve body 33 includes a pressure receiving part 30a,
30t, respectively, to relieve the pressure of the flow path 15 and port 32a. When the pressure Pa of the port 32a is larger than the pressure Pb of the flow path 15 (P a > P b ), the valve body 33 is in the state shown in the figure, and the ports 32 a and 32 b are brought into communication. In the opposite case (Pa (Pb), the valve body 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 is greater than the specified value 4, the valve body 33 releases the spring. 30c
In other words, when the fluid is immersed in the direction from the port 82b to the port 32a and the flow rate becomes larger than the specified value, the flow path is closed. The ports 32a and 32 are opened by the operation of the valve body 33.
The pressure difference between the valve body and the valve body becomes larger and larger, which facilitates the operation of the valve body.

Therefore, the throttle 31 is adjusted in accordance with the flow rate flowing through the overspeed prevention valve 3.
If this is adjusted, when the flow rate exceeds the specified value, the main valve 30 will act to block the ports 32a and 32b, thereby blocking the flow of fluid. This is to cut off the fluid flowing out of the cylinder 1, and to safely stop the ride wheel 10 without increasing the speed above a specified speed.

In the figure, a single throttle is illustrated as the throttle 31, but the same effect can be obtained by using the control valve 2, and the structure is not limited to that shown in the figure.As mentioned above, the control valve 2 generates a pressure difference when descending. By operating the overspeed prevention valve 3 using a pressure difference, the structure of the valve device can be simplified.

FIG. 11 shows another embodiment of the overspeed prevention valve 3, and FIG. 12 shows its more specific structure.

The overspeed prevention valve 3 consists of a main valve 30, pilot valves 34 and 35, and a throttle 31. The throttle 31 is a baffle plate or the like that adjusts the flow path area according to the flow rate (as explained in FIG. 10, the throttle 31 may be replaced with a fluid resistance of the control valve 2).
, the main valve 30 includes a valve body 32, a valve body 33, and springs 30c, 30.
f and fluid chambers 30c, 30d, and 30f, and ports 3, Oa, 30b, and 30 connected to each fluid chamber.
e, and each port has flow paths 15a, 15b, 16 (
Connected to tank 9). The valve bodies 33d and 33e are the pressure receiving part 33
a.

88b, each receiving pressure from pilot valves 34 and 35. The pilot valves 34, 35 are two-position, three-way switching valve bodies, and have valve bodies 38, 39.
The fluid is switched depending on the operating position of 9. The end faces thereof receive pressure from ports 30a, 30b via channels 37a, 37d and 137b, 37s.

When the pressure Pa of the port 30a is greater than the pressure pb of the port 30b (Pa>Pb), the valve bodies 34 and 35 are in the state shown, and the flows j137b and 37a.

37f and 37e are communicated, and channels 37b and 37d are blocked. In the opposite case (Pa<Pb), the valve bodies 34 and 35 are in the opposite position as shown, and the flow paths 37c and 37b, 37f and 37
d is communicated, and 37a and 37g are cut off. That is, the high pressure side of the port Boa, 30b is connected to the pressure receiving part 33a of the valve body 83d of the main valve, and the low pressure side is connected to the pressure receiving part 33b of the valve body 33. Therefore, the valve bodies 33d and 33e are connected to the ports 30a and 3
It receives a force to the right corresponding to the pressure difference with 0b. When this force becomes larger than the specified value, the valve bodies 33d and 33e move in the direction of closing the flow path between the ports 30a and 30b against the force of the spring 30c.
The pressure difference between 0a and 30b becomes increasingly large, facilitating the movement of the valve body. In other words, if the throttle 31 is adjusted in accordance with the flow rate flowing through the overspeed prevention valve 3, when the flow rate exceeds the set value, the main valve 30 will operate, blocking the port 30b and connecting the ports Boa and 30e. communicate.

This means that when the elevator is going up, the fluid discharged from the pump 6 is returned to the tank 9, closing the flow path to the cylinder 1, and when the elevator is going down, the fluid flowing out of the cylinder 1, as it were, is returned to the tank 9. This is to shut off the pump and supply fluid from the tank 9 to the pump 6, and in either case, it is possible to safely stop the ride and lO without increasing the speed beyond the specified speed. Further, as described above, the pump is protected from abnormally high pump discharge pressure or abnormally low suction pressure (vacuum).

When the temperature of the fluid changes, the viscosity also changes, which changes the control characteristics of the control valve and the volumetric efficiency of the pump, leading to a decrease in ride comfort and an increase in energy loss. used in range. However, using a heater as an energy source to heat this fluid will increase the cost, so in the embodiment of the present invention, the relief valve 4 is provided with a structure that can change the set pressure in two stages so that unloading operation is also possible. , the fluid temperature is increased by unloading 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 is a valve body 40
The main components are a valve body 41, a pilot valve 43, and a pilot valve 44 for setting unload pressure. The valve body 41 is connected to the shaft 4
1a, and there are fluid chambers 40d (back of the poppet), 408 (shaft end surface), and 40 between the valve body 40 and the valve body 40.
c (poppet side). Fluid chamber 40d
communicates with the port 40a via the aperture 42, and the aperture 42a
It communicates with the fluid chamber 40e via. port 40a,
40b are connected to channels 15a and 16, respectively. The pilot valve 43 communicates with the fluid chamber 40d and includes a valve body 43a, a spring 43b, and a screw 43c, and adjusts the pushing force of the spring 43b to set the relief pressure of the fluid chamber 40d.

The other pilot valve 44 communicates with the fluid chamber 40e, and the valve body 4
4a.

Consisting of a spring 44b and a solenoid 44c, it is normally open, but when the solenoid 44c is energized, the fluid chamber 40e opens.
open to the atmosphere.

In the relief valve 4, under normal conditions, the forces acting on the valve body 41 from the fluid chambers 40d and 40e are larger than the forces acting from 40a and 40c, blocking the ports 40a and 40b as shown in Figure 1. 40b is tank pressure). Port 40a
When the pressure becomes higher than the pressure set by the pilot valve 43, the pilot valve 43 opens and the fluid chambers 40d and 4
By discharging the fluid 0e, the poppet 41 is displaced against the force of the spring 41b and the pressure of the fluid chambers 40d and 40e, and the fluid flows from the port 4Qa to 40b, without increasing the pressure of the port 40a any further.

When this relief valve 4 is used as an unloading valve, by energizing the pilot valve 44 and opening the fluid chamber 40e to the tank 9, the force acting on the back surface of the poppet 41 is reduced by the cross-sectional area of the shaft 41a. The main valve opens even if the pressure in 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, regardless of the set value of the relief pressure, the unload pressure is always set smaller than the relief pressure by a fixed value.

FIG. 14 is a sectional view showing the structure of another embodiment of the relief valve. The same symbols as in FIG. 13 represent parts that perform the same functions. Setting of the relief pressure is the same as in the embodiment shown in FIG. 13, and is set by the pilot valve 43. The unloading pressure is set by limiting the amount of displacement of the valve body 41 using a stopper 45.
For unloading, the pilot valve 44 is energized and the fluid chamber 40d is
is opened to the atmosphere and the valve body 41 is moved 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 body 41 is larger during the unload action than during the relief action. Therefore, it becomes possible to set the unload pressure separately from the setting of the relief pressure.

In this case, compared to the embodiment shown in FIG. 13, setting the unload pressure requires more effort, but the structure of the relief valve is simplified.

FIG. 15 is a fluid pressure circuit diagram of a different embodiment from FIGS. 1 and 2 of the hydraulic elevator according to the present invention. In the figure, 1 is a fluid pressure cylinder that directly or indirectly drives the seat 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
1 is a check valve for protecting the pump, 6 is a fluid pressure pump capable of forward and reverse rotation, 7 is a motor, 8 is a filter, and 9 is a fluid tank. 11 is an inverter that drives the motor 7, 12 is an elevator control device, and 15, 16, and 17 are flow paths.

The pilot-operated check valve 2 consists of a main valve 20 and a pilot valve 21, and normally shuts off the flow of fluid from the fluid pressure cylinder 1 and allows the flow to the fluid pressure cylinder 1, as shown in the figure. There is. When a command is input to the pilot valve 21, the main valve 20 is opened and the fluid can be discharged from the hydraulic cylinder 1.The overspeed prevention valve 3 consists of a throttle 31, a main valve 30, and a pilot valve 34,35. Normally, fluid flows through the throttle 31 and the main valve 3o as shown in the figure. If the pressure difference before and after the overspeed prevention valve 3 exceeds a preset specified value, that is, if the flow rate exceeds the specified value, the pilot valve 3
Fluid pressure acting on the main valve 30 through 4.35 switches the main valve 30 to control fluid flow.

In this embodiment having such a configuration, a case in which the seat 10 is raised and a case in which it is lowered will be explained.

(1) When ascending Based on the ascending command and speed signal from the control device 12, the inverter 11 is driven to gradually start and accelerate the motor 7 (the rotational direction at this time is set as forward rotation). Thereafter, the motor 7 is accelerated to the rated rotation speed according to the speed signal, and is further driven at the rated rotation speed. When the fluid pressure pump 6 is activated and accelerated in the forward direction, fluid passes through the filter 8 and is sucked into the fluid pressure pump 6, where the pressure is gradually increased. The high-pressure fluid passes through an overspeed prevention valve 3 and a pilot-operated check valve 2, and is supplied to the fluid pressure cylinder 1. At this time, as the motor rotation speed increases, the discharge flow rate of the fluid pressure pump 6 also increases, and the fluid pressure cylinder 1 is started and gradually accelerated to the rated speed. The car 10, which is driven directly or indirectly by the fluid pressure cylinder 1, is also started and accelerated in proportion to the speed signal (motor rotational speed) to reach the rated speed. On the other hand, if the rotational speed of the motor 7 is reduced by a deceleration signal (speed signal), the speed of the fluid pressure cylinder 1 will be reduced, contrary to the case of acceleration, and will eventually come to a stop. In other words, the vehicle and the vehicle 10 also decelerate and stop.

(2) At the time of descent, the pilot valve 21 of the pilot-operated check valve 2 is operated by the descent start signal from the control device 12, and the main valve 20 is switched. 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 in the opposite direction to the upward movement.
(accelerated negative rotation).

The pump 6 sucks high pressure fluid from the fluid pressure cylinder 1 and returns it to the tank. If the main valve 20 is suddenly switched at this time, the fluid in the flow paths 15a and 15b will be rapidly compressed, resulting in a large shock. Therefore, in order to ensure good elevator ride comfort, it is desirable to switch the main valve 20 gently. In the same way as when ascending, the motor accelerates, drives at rated speed, decelerates, and stops, and the car also accelerates, runs at rated speed, decelerates, and then comes to a stop. After that, when the signal to the pilot valve 21 is released, the main valve 20 also returns to its initial state.

The relief valve 4 is installed to protect the fluid pressure device, and prevents the fluid pressure from becoming abnormally high. Also, pilot valve 13. It operates together with the throttle valve 14 to perform unloading operation. The check valve 5 prevents the pilot-operated check valve 2 and the fluid pressure pump 6 from becoming out of synchronization during the downward movement, thereby preventing the flow path 15 from becoming vacuum. That is, when the pressure in the flow path 15 becomes low, fluid is sucked into the flow path 15 from the tank 9 via the flow path 16.

Regardless of the flow direction of the fluid, the overspeed prevention valve 3 switches the main valve 30 and closes the circuit 15b when the amount of pressure drop across the main valve 30 and the throttle 31 exceeds a specified value, that is, when the flow rate exceeds the specified value. The flow path 15a is connected to the flow path 16.

As a result, the flow of fluid into and out of the hydraulic cylinder 1 is stopped, and the fluid discharged from the pump 6 is returned to the tank 9. When ascending and descending, the operations are as follows.

When rising, fluid flows from the pump 6 to the main valve 30 of the overspeed prevention valve 3.
Throttle valve 31. It flows through a pilot-operated check valve 2 to a hydraulic cylinder. If the amount of pressure drop (Pa-Pb) between the main valve 30 and the throttle valve 31 at this time is larger than the specified value, the pilot valves 34 and 35 will be in the illustrated state. However, Pa
is the pressure in the flow path 15a, and pb is the pressure in the flow path 15b.

Then, the pressure receiving part 3 of the main valve 30, which will be described later with reference to FIG.
Since Pa acts on the pressure receiving part 3a and pb acts on the pressure receiving part 33b (Pa>Pb), the main valve 30 switches against the force of the spring 33C, blocks the flow path 15b, and closes the flow path 15a.
is communicated with the flow path 16. As a result, the supply of fluid to the hydraulic cylinder 1 is stopped, and the fluid discharged from the pump 6 returns to the tank 9.

During descent, fluid flows from the hydraulic cylinder 1 to the pilot operated check valve 2. It flows through the throttle 31° of the overspeed prevention valve 3 and the main valve 30 to the pump 6. At this time, if the pressure drop amount (Pb-Pa) of the throttle valve 31 and the main valve 30 is larger than the specified value, the pilot valves 34 and 35 are switched from the illustrated state, and the main valve 3o
Since pb acts on the pressure receiving part 33a and Pa acts on the pressure receiving part 33b (Pb)Pa), the main valve 30
is switched. Therefore, the discharge of fluid from the fluid pressure cylinder 1 is stopped in the same way as when rising.

FIG. 16 shows the structure of one embodiment of the pilot operated check valve 2. As shown in FIG. The main valve 2o has a valve body 22, a valve body 23, a spring 23c, and a stopper 25a as main components, and its ports 22b and 22c are connected to flow paths 15b and 15c, respectively. The valve body 23 has an orifice 23b in a skirt portion 23a, and its displacement is limited by a stopper 25a.

The pilot valve 21 has a valve body 26, a valve body 27, and a solenoid 28 as its main components, and has ports 26a and 26b.
, 26c are the port 22c and the fluid chamber 22e of the main valve 20, respectively.
, connected to tank 9 0 Normally, port 26a
and 26b are communicated with each other, high pressure fluid from port 22c is introduced into fluid chamber 22e, and valve body 23 is held at the illustrated position. When the solenoid 28 is excited by a command, the valve body 2
7 is driven, ports 26a and 26b are shut off, ports 26b and 26c are communicated, and fluid chamber 23e is connected to tank 9.
open to As a result, the valve body 23 operates against the force of the spring 23c due to the fluid pressure acting on the fluid chamber 22d, thereby communicating the ports 22c and 22b. When raising the elevator, the fluid discharged from the hydraulic pump 6 flows from the port 22b (flow path 15b) to the port 22c (fluid 15c) (
(free flow) and pushes up the hydraulic cylinder 1. When lowering, the solenoid 28 is energized by a lowering signal to connect ports 22c and 22b of the main valve 20, the high pressure fluid in the hydraulic cylinder 1 is discharged by the hydraulic pump 6, and the hydraulic cylinder 1- is lowered. . When the lowering is completed, the solenoid is deenergized, high pressure fluid is introduced into the fluid chamber 22e, and the main valve 20 returns to the state shown. At this time, the throttle valve 29 controls the operating speed of the valve body 23 and the skirt 23
The orifice 23b provided at a gradually increases the opening area between the ports 22c and 22b. This orifice 2
3b and the throttle 29 prevent the occurrence of elevator startup shock.

FIG. 17 is a diagram showing an example of the structure of the overspeed prevention valve 3, and FIG.
The figure is an enlarged view of the pilot valve 33, and FIG. 19 is an enlarged view of the pilot valve 34. The flow path area of the throttle 31 is adjusted using a baffle plate or the like according to the flow rate. Main valve 3
0 consists of a valve body 32, a valve body 33, and a spring 33c, and has a fluid chamber 30d.

30e, 30f and a port 30a connected to each fluid chamber.

30b and 30c, and each port is a flow path 15a.

Connected to 15b and 16 (tank 9). The valve body 33 has pressure receiving parts 33a and 33b, each having a pilot valve 34 and 35.
receive pressure from The pilot valves 34, 35 are two-position, three-way switching valves, with grooves or equivalent parts 38a, 38b.

It has valve bodies 38 and 39 provided with valve bodies 39a, and valve bodies 38°39
The fluid is switched depending on the operating position. A port 30a is connected to the end face through flow channels 37a, 37d, 37b, and 37e.
, 30b. When the pressure Pa of the port 30a is higher than the pressure pb of the port 30b (Pa<Pb), the valve bodies 38 and 39 are in the state shown in the figure, and the flow paths 37a and 37
c, 37e and 37f are communicated, and flow paths 37b and 37d are blocked. In the opposite case (Pa (Pb)), the valve bodies 38 and 39 are in the opposite position to that shown in the figure, and the flow paths 37b and 37c.

37d and 37f are communicated, and 37a and 37e are blocked.

In other words, the high pressure side of the ports 30a and 30b is connected to the main valve body 36.
The low pressure side is connected to the pressure receiving part 36a and the pressure receiving part 26b.

Therefore, the valve body 36 receives a force in the right direction corresponding to the pressure difference between the ports 30a and 30b. When this force becomes larger than a specified value, the valve body 33 moves in the direction of closing the flow path against the spring 33c.
The pressure difference between and 30b becomes increasingly large, facilitating the movement of the valve body. That is, if the throttle 31 is adjusted in accordance with the flow rate flowing through the overspeed prevention valve 3.

When the flow rate exceeds the set value, the main valve 30 acts to block the port 30b and communicate the ports 30a and 30c. This means that if the elevator is going up, the pump discharge fluid is returned to the tank and the flow path to the hydraulic cylinder 1 is closed, and if the elevator is going down,
The purpose is to shut off the fluid flowing out from the fluid pressure cylinder 1, and in either case, the car 10 is stopped safely without increasing the speed above a specified speed.

FIG. 20 shows an example of the structure of the relief valve 4 which also serves as an unload valve. This 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 components. The valve body 41 has a poppet shape with a shaft 41a, and there are fluid chambers 40C (poppet back surface), 40d (shaft end surface), and 408 between the valve body 40 and the valve body 40.
(front of poppet). The fluid chamber 40c communicates with the port 40a via a throttle 45, and communicates with the fluid chamber 40d via a throttle 48. Ports 40a, 40b
are connected to flow paths 15a and 16, respectively. The pilot valve 43 communicates with the fluid chamber 40c, and the valve body 43a and the spring 43
b and a screw 43c, and adjusts the pressing force of the spring 43b to set the relief pressure of the fluid chamber 40c. The other pilot valve 44 communicates with the fluid chamber 40d and includes a valve body 44a, a spring 44b, and a solenoid 44c, and is normally closed, but when the solenoid 44c is energized, the fluid chamber 40d is opened to the atmosphere.

In the relief valve 4, the force acting on the valve body 46 from the fluid chambers 40c and 40d is normally larger than the force acting on the valve body 40e, and the ports 40a and 40b are shut off as shown in the figure.
Port 40b is tank pressure).

When the pressure in port 40a becomes greater than the pressure set by pilot valve 43, pilot valve 43 opens, discharging the fluid in fluid chambers 40c and 40d, displacing poppet 41 against spring 41b, and moving from port 40a to 40b. The fluid is allowed to flow and the pressure in port 40a is not increased any further.

When this relief valve 4 is used as an unloading valve, if the pilot valve 44 is energized to open the fluid chamber 40d to the tank 9, the force acting on the back surface of the poppet 41 is reduced by the cross-sectional area of the shaft 41a. The main valve opens when the port 40a has a pressure 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, regardless of the set value of the relief pressure, the unload pressure is always set smaller than the relief pressure by a fixed value. This means that the vehicle can be stopped safely without increasing the speed beyond the specified speed.

FIG. 20 shows an example of the structure of the relief valve 4 which also serves as an unload valve. This 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 components. The valve body 41 is connected to the shaft 4
1a, and there are fluid chambers 40c (poppet back), 40d (shaft end surface), and 40 between the valve body 40 and the valve body 40.
e (poppet front). Fluid chamber 40c
communicates with the port 40a via a throttle 45, and communicates with the fluid chamber 40d via a throttle 48. Port 40a, 4
0b are connected to flow paths 15a and 16a, respectively. The pilot valve 43 communicates with the fluid chamber 40c, and includes a valve body 43a, a spring 43b, and a screw 43c, and sets the relief pressure of the fluid chamber 40c by adjusting the pressing force of the spring 43b.

The other pilot valve 44 communicates with the fluid chamber 40d, and the valve body 4
The fluid chamber 40d is normally closed, but when the solenoid 44c is energized, the fluid chamber 40d is opened to the atmosphere.

FIG. 21 is a sectional view showing the structure of another embodiment of the relief valve. The same symbols as in FIG. 20 represent parts that perform the same functions. Setting of the relief pressure is the same as in the embodiment shown in FIG. 20, and is set by the pilot valve 43. However, the unload pressure settings are different. When the pilot valve 13 is energized, the fluid in the fluid chamber 40c flows through the pilot valve 44. It passes through the throttle 46 and opens into the tank. Therefore, the unloading pressure is set by adjusting the two throttles 45 and 46.

Note that the overspeed prevention valve 3 shown in FIG. 12 can also be employed in the embodiment shown in FIG. 15. The overspeed prevention valve 3 in FIG.
Although it has the same structure as the overspeed prevention valve shown in FIG. 7, it also has the function of the pump protection check valve (suction valve) 5. That is, the difference from the embodiment shown in FIG. 17 is that the valve body 33 is divided into 33d and 33e, and a spring 33f is added. The valve bodies 33d and 33e work together to prevent overspeeding when the elevator ascends and descends, similar to the case described with reference to FIG. 17. The spring 33f normally prevents the two valve bodies 33d and 33e from performing secondary operation.

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 functions as a suction valve.
Since the pressure is the same as or higher than that, the valve bodies 38 and 39 of the pilot valve are located below, and the flow paths 37c and 37f are
It communicates with 7.b and 37d. Therefore, the valve body 33
A force acts on e from the left, and the left end surface (fluid chamber 30f
) is pushed to the right by the pressure acting on the tank 9, causing the ports 30C and 30a to communicate with each other, and supplying fluid from the tank 9 to the fluid pressure pump 6. This is the function of the suction valve 5 itself.

〔Effect of the invention〕

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

(1) Since the pilot-operated check valve used to maintain the car's position is gradually switched, the pressure in the flow path between the check valve and the fluid pressure pump slowly increases when the elevator starts descending. This prevents the generation of surge pressure and provides smooth downward acceleration characteristics.

(2) The structure is such that pilot fluid pressure is supplied by excitation of the pilot valve to operate the main valve of the control valve, and the excitation is released to return the main valve to normal operation. Therefore, in the event of an abnormality such as a power outage, the control command can be cut off. , the main valve can quickly shut off the flow path and prevent the single car from descending at high speed.

(3) Regardless of the driving direction of the car, if the flow rate of fluid passing through the overspeed prevention valve exceeds a specified value, the overspeed prevention valve will operate, and if the elevator is going up, the pump discharge flow will be returned to the tank. , interrupting the flow path between the hydraulic cylinder and the hydraulic pump and, in the case of elevator descent, interrupting the flow from the hydraulic cylinder, and in both cases safely stopping the elevator car.

(4) The relief valve of the present invention naturally operates as a relief valve, but it can also act as an unload valve by switching the pilot valve, and the unload operation generates heat in the fluid and controls the temperature of the fluid. It also becomes possible.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing one embodiment of a fluid pressure elevator according to the present invention, FIG. 2 is a circuit diagram showing another embodiment of a fluid pressure elevator according to the present invention, and FIG. 3 is a circuit diagram showing an example of a control valve according to the present invention. FIG. 4 is a diagram showing the structure of the embodiment shown in FIG. 3. FIG. 5 is a diagram showing the structure of another embodiment of the control valve. FIG. 6 is a diagram showing the structure of another embodiment of the control valve. 7 is a diagram showing the structure of another embodiment of the control valve, FIG. 8 is a diagram showing the structure of yet another embodiment of the control valve, and FIG. 9 is a diagram showing the structure of another embodiment of the control valve. FIG. 10 is a diagram showing the structure of another embodiment of the overspeed prevention valve according to the present invention.
Fig. 1 is a diagram showing the structure of another embodiment of the overspeed prevention valve according to the present invention, Fig. 12 is a diagram showing a more specific structure of the overspeed prevention valve, and Fig. 13 is a diagram showing a relief valve with an unload function. A diagram showing the structure of one embodiment, FIG. 14 is a diagram showing the structure of another embodiment of the relief valve with an unloading function, and FIG. 15 is a circuit diagram showing another embodiment of the fluid pressure elevator according to the present invention. Figure 16 shows the structure of a pilot-operated check valve, Figure 17 shows the structure of an overspeed prevention valve, and Figures 18 and 19.
Figure 20 shows the structure of the pilot valve of the overspeed prevention valve.
The figure shows the structure of a relief valve that also serves as an unload valve.
FIG. 21 is a diagram showing the structure of another relief valve. 1... Fluid pressure cylinder, 2... Control valve (pilot operated check valve with flow control function), 3... Overspeed prevention valve, 4... Relief valve with unloading function, 5...・
Suction valve (check valve), 6...Fluid pressure pump, 7.
...Motor, 8...Filter, 9...Fluid tank,
10... Car, 11... Inverter, 12...
・Elevator #Leg device, 13...Pilot valve, 15
, 16° 17... Flow path, 20... Control valve main valve, 21
...Pilot valve, 22...Control valve body, 23...
・Skirt portion, 24... Piston, 25... Stopper, 30... Overspeed prevention valve main valve, 31... Throttle valve, 3
2... Overspeed prevention valve body, 33... Valve body, 34, 35
...Pilot valve, 4o...Relief valve body, 41
...Valve body, 42... Throttle, 43... Pilot valve, 44... Pilot valve for setting unload pressure, 45...
...Stopper, 46...Pilot valve body, 47...
- Valve body, 48... orifice.

Claims (1)

[Claims] 1. The flow rate of fluid supplied to or discharged from the fluid pressure cylinder is controlled by controlling the rotation speed of the fluid pressure pump, and the flow rate of fluid supplied to or discharged from the fluid pressure cylinder is directly or indirectly In a fluid pressure elevator that raises or lowers a car, a pilot operated type is provided between the fluid pressure pump and the fluid pressure cylinder, and when the pilot valve is deenergized, the pilot pressure fluid is discharged and the main valve is closed. A fluid pressure elevator characterized by having a check valve installed. 2. In the fluid pressure elevator according to claim 1, the check valve includes a skirt portion formed with an orifice that gradually increases or decreases the opening area of the check valve as the valve body of the check valve operates. A fluid pressure elevator characterized in that it is provided on a valve body of a valve. 3. The hydraulic elevator according to claim 1 or 2, wherein the check valve is gradually opened to substantially balance the fluid pressure between the fluid pressure cylinder and the fluid pressure pump with the pressure of the fluid pressure cylinder, and then A fluid pressure elevator characterized in that the fluid pressure elevator is equipped with a control means for starting the fluid pressure pump and lowering the car. 4. In the fluid pressure elevator according to any one of claims 1 to 3, the valve opening degree when fluid flows in the reverse direction is regulated to be smaller than the valve opening degree when fluid flows in the forward direction through the check valve. A fluid pressure elevator characterized in that it is equipped with a stopper for a valve body that applies a force to the valve body in a direction that always closes the valve when fluid flows in the opposite direction. 5. The fluid pressure elevator according to any one of claims 1 to 4, wherein a piston that opens the check valve so that fluid flows in the opposite direction according to a control command and a valve body that controls the flow of fluid, A fluid pressure elevator characterized in that the valve body is relatively slidably fitted together and only the valve body moves when fluid flows in the forward direction. 6. Control the flow rate of fluid supplied to or discharged from the fluid pressure cylinder by controlling the rotation speed of the fluid pressure pump, and raise or lower the car directly or indirectly with the fluid pressure cylinder. In the fluid pressure elevator, a throttle valve and a control valve are disposed between the fluid pressure cylinder and the fluid pressure pump, and the control valve is operated by the pressure difference before and after the throttle valve and the control valve. A fluid pressure elevator, characterized in that the valve is configured to decelerate and stop the car by blocking a flow path between the car and the fluid pressure pump. 7. The fluid pressure elevator according to any one of claims 1 to 5, wherein a throttle valve and a control valve are disposed between the fluid pressure cylinder and the fluid pressure pump, and the control valve is connected to the throttle valve and the control valve. A fluid pressure elevator characterized in that the valve is operated by a pressure difference before and after the control valve to shut off a flow path between the fluid pressure cylinder and the fluid pressure pump to decelerate and stop the car. 8. The fluid pressure elevator according to claim 6 or 7, wherein the control valve operates by always receiving the higher fluid pressure of the fluid pressure cylinder and the fluid pressure pump, so that the control valve operates by always receiving the higher fluid pressure of the fluid pressure cylinder and the fluid pressure pump. A fluid pressure elevator characterized in that the valve is a valve that isolates a fluid pressure pump from and communicates the fluid pressure pump with a fluid tank. 9. Control the flow rate of fluid supplied to or discharged from the fluid pressure cylinder by controlling the rotation speed of the fluid pressure pump, and raise or lower the car directly or indirectly with the fluid pressure cylinder. In a fluid pressure elevator, when the outlet pressure of the fluid pressure pump exceeds a predetermined value, the fluid discharged from the fluid pressure pump is discharged into a fluid tank in a flow path branching from the flow path connecting the fluid pressure pump and the fluid pressure cylinder. A fluid pressure elevator characterized by being provided with a relief valve. 10. The fluid pressure elevator according to any one of claims 1 to 8, wherein a flow path branching from a flow path connecting the fluid pressure pump and the fluid pressure cylinder has an outlet pressure of the fluid pressure pump at a predetermined value. A fluid pressure elevator characterized in that a relief valve is provided for discharging fluid discharged from a fluid pressure pump into a fluid tank. 11. The fluid pressure elevator according to claim 9 or 10, wherein a shaft is provided on the valve body of the relief valve, and one of the valve body and the shaft is controlled by pressure from a pilot relief valve, and the valve body and the shaft are controlled by pressure from a pilot relief valve. A fluid pressure elevator characterized in that the other of the relief valves is controlled by pressure from a pilot switching valve, and relief pressure and unload pressure can be set in the relief valve. 12. The fluid pressure elevator according to any one of claims 9 to 11, wherein the pilot chamber is connected to a pilot relief valve and a pilot switching valve, and when the pilot switching valve is energized, the valve body of the relief valve is 1. A fluid pressure elevator characterized in that a stopper for mechanically regulating the position is provided, and a relief pressure and an unload pressure can be set for the relief valve. 13. By controlling the rotational speed of the fluid pressure pump, the flow rate of fluid supplied to or discharged from the fluid pressure cylinder is controlled, and the car is raised or lowered directly or indirectly by the fluid pressure cylinder. In the fluid pressure elevator, a throttle valve and a control valve are disposed between the fluid pressure cylinder and the fluid pressure pump, and the control valve is operated by the pressure difference before and after the throttle valve and the control valve. A fluid pressure elevator, characterized in that the valve is a valve that blocks a flow path between the fluid pressure pump and the fluid pressure pump and discharges fluid discharged from the fluid pressure pump into a fluid tank. 14. The fluid pressure elevator according to claim 13, wherein a pilot-operated check valve is disposed between the fluid pressure pump and the fluid pressure cylinder, and the check valve is operated as a valve body of the check valve operates. A fluid pressure elevator characterized in that the valve body of the check valve is provided with a skirt portion in which an orifice is formed to gradually increase or decrease the opening area of the check valve. 15. The fluid pressure elevator according to claim 14, wherein the valve body is divided into a valve body that switches the direction of fluid flow at the same time as it receives pilot pressure, and a valve body that receives pilot pressure, and the valve body is divided into a valve body that switches the direction of fluid flow at the same time as it receives pilot pressure, and a valve body that receives pilot pressure. When the pressure difference between the fluid pressure cylinder and the hydraulic cylinder exceeds a predetermined value, the fluid pressure pump and the fluid pressure cylinder operate integrally to shut off the flow path, while when the flow rate exceeds a predetermined value, the valve body operates individually. A fluid pressure elevator characterized by a valve body that operates separately and regulates the flow rate. 16. In the fluid pressure elevator according to any one of claims 13 to 15, when the outlet pressure of the fluid pressure pump reaches a predetermined value or more, the discharge fluid of the fluid pressure pump is transferred to a flow path branched from the flow path. A fluid pressure elevator characterized by being equipped with a relief valve for discharging into a tank. 17. The fluid pressure elevator according to claim 16, wherein a shaft is provided on the valve body of the relief valve, one of the valve body and the shaft is controlled by pressure from a pilot relief valve, and one of the valve body and the shaft is controlled by pressure from a pilot relief valve. A fluid pressure elevator, characterized in that the other one is controlled by pressure from a pilot switching valve, and a relief pressure and an unload pressure can be set in the relief valve. 18. The fluid pressure elevator according to any one of claims 16 to 17, wherein the pilot chamber is connected to a pilot relief valve and a pilot switching valve, and when the pilot switching valve is energized, the valve body of the relief valve is 1. A fluid pressure elevator characterized in that a stopper for mechanically regulating the position is provided, and a relief pressure and an unload pressure can be set for the relief valve.