JPH11189379A - Hydraulic elevator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress shocks at over-speed restraint or at emergency stoppage of a hydraulic elevator being lowered that has a large pressure ratio expressed as the cylinder pressure at the full load divided by that at the zero load. SOLUTION: In series with a check valve 100, a two-way valve 300 is arranged which is designed not to fully close or to have its maximum opening angle while an elevator is operated normally and its minimum opening angle at over-speeding or emergency including a service interruption while the elevator is lowered. At an emergency including a service interruption during such lowering operation, the closing action of the check valve 100 is retarded from the switching action of the two-way valve 300 from the maximum opening angle to the minimum opening angle, or the overall passage area of these two valves or the check valve 100 and two-way valve 300 is phased as long as the check valve 100 is fully closed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention controls the flow rate of fluid supplied to or discharged from a hydraulic cylinder by controlling the number of revolutions of a motor for driving a hydraulic pump at a variable speed. , A hydraulic elevator of the type that controls the speed of a car supported directly or indirectly, particularly a hydraulic elevator having a large pressure ratio (expressed as cylinder pressure at 100% loading / cylinder pressure at 0% loading) .

[0002]

2. Description of the Related Art A motor for driving a fluid pressure pump is supplied to a fluid pressure cylinder by controlling the rotation speed of the motor at a variable speed.
Alternatively, in a hydraulic elevator in which the speed of a car supported directly or indirectly on the top of a hydraulic cylinder is controlled by controlling the flow rate of a fluid to be discharged, the position of the car is maintained when the car stops. The stop valve is disclosed, for example, in Japanese Patent Publication No. 4-153171.

[0003]

In the above prior art, when an abnormality occurs in the control of the motor during the descent operation, the occurrence of overspeed during the descent operation is limited even if the pilot valve is delayed in operation. As one method for safely stopping the car, the maximum valve opening is mechanically limited by a stopper.

On the other hand, when a counterweight is added, when the weight of the car is reduced and the load is made equal to the conventional one, or when the load is increased without changing the weight of the car, 100% loading is performed. When the cylinder pressure of the above is set to the full load pressure Pfl and the cylinder pressure at the time of 0% loading is set to the no-load pressure Pnl, and these ratios are expressed by α = Pfl / Pnl, the value of α increases.

[0005] In such a case, if the maximum valve opening is limited in order to limit the overspeed at full load pressure during the descent operation, the valve may be throttled so that the rated speed cannot be obtained at no load pressure. Occurs. A specific example will be described with reference to FIG.

FIG. 9 shows a hydraulic cylinder 200 and a pulley 20.
3, plunger 204, rope 202, car 20
1, a motor 2 driven at a variable speed by an inverter (not shown), a fluid pressure pump 1 driven by the motor 2,
A flow path 222 between the fluid pressure pump 1 and the fluid pressure cylinder 200,
2 shows a hydraulic elevator with a non-return valve 100A, a filter 3 and a tank 4 arranged between 223.

Here, the weight of the car 201 is Wc, the loading capacity of 100% of passengers or luggage, etc. is Wl, the pressure receiving area of the plunger 204 is S, and the check valve 1 which is opened at the time of descending operation.
Let A be the opening area of 00A. The cylinder pressure Pfl at the time of 100% loading is expressed by the following equation.

[0008]

(Equation 1)

The cylinder pressure Pnl at the time of 0% loading is
It is expressed by the following equation.

[0010]

(Equation 2)

Therefore, the pressure ratio α is expressed by the following equation.

[0012]

(Equation 3)

On the other hand, the relationship between the opening area A of the check valve 100A during the descent operation and the flow rate Q corresponding to the car speed is as follows.
It is expressed by the following equation.

[0014]

(Equation 4)

Here, K is a proportionality constant, and P is a check valve 100
A is the pressure loss. For example, when loading 100%, the speed is limited at 140% of the rated speed, that is, the flow rate is limited. If the flow rate at that time is Qmax, the opening area of the check valve 100A is Amax, and the pressure loss of the flow path and the like is ignored, Amax is selected so as to satisfy the following equation.

[0016]

(Equation 5)

On the other hand, the maximum flow rate Q ₀ at 0% loading at Amax can be expressed by the following equation.

[0018]

(Equation 6)

Hereinafter, two cases are assumed.

(1) Case 1 In general, since a hydraulic elevator has Wc ≧ W1, α = 2, for example, even if Wc = Wl. In this case, by selecting the Amax as described above, when determining the maximum flow rate Q ₀ at 0% loading, it expressed the rated speed Qr Tosureba by the following equation.

[0021]

(Equation 7)

Therefore, if all of the cylinder pressure can be used as the loss of the check valve 100A, the rated speed can be secured.

(2) Case 2 On the other hand, by equivalently or directly reducing the weight of the car 201 by means such as attaching a counterweight to the car 201, W
Let c <Wl. For example, if Wc = 0.5 Wl, α = 3. Also in this case, Amax is selected as described above and 0%
The flow rate Q ₀ at the time of loading is obtained. Similarly, assuming that the rated speed is Qr, the flow rate Q ₀ is expressed by the following equation.

[0024]

(Equation 8)

Therefore, the rated speed cannot be obtained even if all of the cylinder pressure is lost in the check valve 100A. Actually, a pressure loss due to the pressure loss of the flow passage 223 and a pressure loss due to packing friction of the fluid pressure cylinder 200 (not shown) are added.

Further, even if the Amax of the check valve 100A can be varied according to the load amount by some means, when the means fails, the check valve 100A may mechanically reach the maximum Amax. is there. To ensure safety,
There is a need for a device having a function capable of mechanically limiting overspeed without depending on control.

As another problem, when the check valve 100A is closed during a descent operation, an emergency such as a power failure, etc., an emergency stop shock generated in the car may increase. In order to ensure safety, it is necessary for the hydraulic elevator to have a function of suppressing an emergency stop shock.

Therefore, the object of the present invention is to provide a pressure ratio (100
(Cylinder pressure at% loading / Cylinder pressure at 0% loading)) is to reduce the overspeed limit during the descending operation of the elevator and reduce the shock at the time of emergency stop.

[0029]

In order to achieve the above-mentioned object, the present invention provides a reverse type in which the opening area is set to be sufficient to obtain the rated speed at the time of the 0% loading lowering operation even in case 2 above. As a means for limiting the overspeed during the descent operation even at 100% loading with a stop valve, supply to the hydraulic cylinder by changing the rotation speed of the motor that drives the hydraulic pump,
Alternatively, in a hydraulic elevator that controls the speed of a car that is directly or indirectly supported on the top of the hydraulic cylinder by controlling the flow rate of the fluid to be discharged, a check is made between the hydraulic cylinder and the hydraulic pump. A two-way valve that is not fully closed is provided in series with the valve. The maximum valve opening is set during normal driving, and the minimum valve opening is set when an overspeed occurs during a descent or in an emergency such as a power failure during a descent.

Further, at the time of descent operation, emergency such as power failure,
As a means for suppressing an emergency stop shock generated in the car when closing the check valve, the closing operation of the check valve in an emergency such as a power failure during a descent operation is performed by setting the two-way valve to the maximum valve opening degree. From the operation to the minimum valve opening degree, or, in the process of fully closing the check valve, changing the total flow area of the two valves including the check valve and the two-way valve to two or more stages. Things.

[0031]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram for explaining a main hydraulic circuit and a control circuit of a hydraulic elevator according to one embodiment of the present invention.

The hydraulic cylinder 200 includes a car 201
Is indirectly driven via a rope 202 and a pulley 203. The car 201 is compensated for a part of its own weight by a counterweight 208 via a rope 206 and a pulley 207.

A two-way valve 100 that is not fully closed is a check valve.
(May be a switching valve or a proportional valve) connected in series to 300,
During normal traveling, the valve opening is the maximum, and in the event of an overspeed at the time of descent or a power failure at the time of descent, the valve opening is the minimum. The fluid pressure pump 1 is driven by a motor 2 and sucks hydraulic oil from a tank 4 via a filter 3. The encoder / pulley rope 209 is fixed to the car 201. The encoder / pulleys 210 and 211 are driven by an encoder / pulley rope 209.

The encoder 212 detects the position of the car 201 based on the rotation angle of the encoder pulley 210. The pressure sensors 220 and 221 detect the pressure of the flow path 222 that connects the hydraulic pump 1 and the check valve 100 and the pressure of the flow path 223 that connects the two-way valve 300 and the hydraulic cylinder 200. The motor 2 is controlled at a variable speed according to a command by a control device 5 including an inverter (not shown).

During the ascending operation, before the check valve 100 opens (in the case of a switching valve or a proportional valve, it is opened), the fluid pressure pump 1
Is once increased to substantially the same pressure as that of the fluid pressure cylinder 200, and then the variable speed operation is performed in the ascending direction along the speed pattern.

During the lowering operation, before the check valve 100 opens (in the case of a switching valve or a proportional valve, it is opened), the fluid pressure pump 1
After the pressure is once increased to substantially the same as the pressure of the fluid pressure cylinder, variable speed operation is performed from the rising direction to the falling direction along the speed pattern. At this time, while the brake is basically applied by the motor 2, the hydraulic oil in the fluid pressure cylinder 200 is discharged to perform the descending operation. The braking energy of the motor 2 is consumed as heat by a resistor (not shown) provided in the control device 5.

The control device 5 takes in the signal of the encoder 212, the signal of the pressure sensors 220 and 221 and the like, and
In addition, the check valve 100 and the like are controlled. In FIG. 1,
Although a fork-shaped indirect hydraulic elevator with a counterweight 208 is shown, the invention is not so limited.

That is, regardless of the presence or absence of the counterweight 208, for example, an underslang shape and a direct shape are also included.
Also, in FIG. 1, since the two-way valve 300 is represented by a hydraulic symbol, it seems that the two-way valve 300 is provided independently between the check valve 100 and the hydraulic cylinder 200. Well, the hydraulic pump 1 and the check valve 1
00 may be provided.

FIG. 2 is a sectional view for explaining a specific structure of the two-way valve 300 shown in FIG. Here, the two-way valve 300 is arranged in series between the check valve 100 and the hydraulic cylinder 200 as shown in FIG.

The two-way valve 300 includes a spool 301, a valve body 302, and a spring 303 as main components, and includes a port 304 communicating with the hydraulic cylinder 200 and a port 305 communicating with the hydraulic cylinder side port of the check valve 100. The spool 301 is provided on the valve body 302 so as to be slidable in the axial direction (lateral direction).

Further, it has two pressure receiving chambers 306 and 307, and guides the cylinder pressure Pc and the pump pressure Pp through the flow paths 308 and 309, respectively. The stopper 310 is located on the pressure receiving chamber 307 side where the pump pressure Pp is led. Is provided. The stopper 310 adjusts the minimum valve opening of the spool 301. The minimum valve opening is set, for example, to be half the rated speed at full load.

The stopper 311 adjusts the maximum valve opening of the spool 301 and adjusts the pressure loss of the two-way valve 300 at the rated speed according to the specification (flow rate) of the hydraulic pressure elevator. . That is, the valve loss in the two-way valve 300 is set to a predetermined valve differential pressure at the time of running at the rated speed.

The land 301 on the left side of the spool 301 in FIG.
A is provided with a seal member 312, and the cylinder port 304 is provided.
Of the working fluid from the pump to the pump port 309, that is, the car 2 when the hydraulic elevator is stopped
It prevents the settlement of 01.

When the pressure is not guided to the pressure receiving chambers 306 and 307, the spool 301 of the two-way valve 300
03 is set so as to always press the stopper 311 in the right direction in the figure, that is, to maintain the maximum valve opening.

The operation of the two-way valve 300 will be described. When incorporated in the hydraulic circuit of FIG. 1, when the car 201 is stopped,
Since the pump pressure Pp is atmospheric pressure, only the cylinder pressure Pc is received, and the minimum valve opening is reached.

Since Pp> Pc during the ascending operation, the two-way valve 300 always maintains the maximum valve opening. Pc during descent operation
> Pp, but the maximum valve opening Xsmax is maintained by the force of the spring 303 in the valve opening direction. And overspeed occurred,
When the pump pressure Pp decreases to a predetermined pump pressure Pp ′,
The valve closing force acting on the pressure receiving chamber 306 overcomes the sum of the valve opening force acting on the pressure receiving chamber 307 and the valve opening force of the spring 303, and operates in the valve closing direction to the minimum valve opening Xsmin.

As a result, the flow rate from the fluid pressure cylinder 200 to the fluid pressure pump 1 is reduced, so that even if the check valve 100 is not closed, the overspeed is limited and the speed Vc of the car 201 is reduced. Therefore, the overspeed can be limited and it is safe. Further, even in an emergency such as a power failure where the torque for driving the hydraulic pump 1 is lost, the pump pressure P
Since p decreases, when the pump pressure decreases to a predetermined pump pressure Pp ′, the same operation is performed, and the minimum valve opening Xsmin is reached. Thereafter, the check valve 100 is fully closed.

By doing so, the flow rate is at least 2
Since the number of steps is reduced, the emergency stop shock at the time of an emergency such as a power failure can be suppressed as compared with when the check valve 100 is fully closed, and the vehicle is stopped in a short traveling distance. When the two-way valve 300 is disposed between the fluid pressure pump 1 and the check valve 100, the same effect can be obtained with the same structure and operation.

FIG. 3 is a diagram for explaining a hydraulic circuit. The same components as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. The main valve section 400 includes a check valve 100 and a two-way valve 300 connected in series with the check valve 100, and its detailed structure is shown in FIG. A component added to FIG.
An operating piston 102, electromagnetic switching valves 106, 107 and 108, which are three pilot valves for controlling a pilot flow rate to the operating piston 102, and a variable throttle 109 provided in the circuit. The electromagnetic switching valve 106 is always closed, and the electromagnetic switching valves 107 and 108 are always open.

Further, there are provided a main relief valve 6, a pilot relief valve 7, a fixed throttle 8, a normally closed electromagnetic switching valve 9, 10, a manual stop valve 11, and a check valve 13.

The operation other than the main valve section 400 will be described. The relief valve 6 is a safety valve provided to release the pressure in the tank 4 when a predetermined pressure is exceeded in the flow path 222 between the fluid pressure pump and the check valve 100.

The pressure is set by a fixed throttle 9 and a relief pilot valve 7 which is a variable throttle. When the electromagnetic switching valve 9 provided in the pilot flow path 250 is excited, the set pressure of the relief valve 6 decreases, and the unload operation of the fluid pressure pump 1 can be performed. Used to warm the working fluid when the temperature of the working fluid in the tank is low.

The electromagnetic switching valve 10 is a valve that lowers a car by using a power supply and a cylinder pressure accumulated in a battery or the like when a power failure occurs. The manual stop valve 11 is an emergency lowering valve that manually lowers the car using cylinder pressure when all the power supply systems fail in an emergency. The check valve 13 is a suction valve that replenishes the working fluid from the tank when the flow path 222 has a negative pressure and prevents cavitation or the like generated in the fluid pressure pump 1.

In the valve body 401 of the main valve section 400,
The main valve 101 of the check valve 100, the operating piston 102, the springs 103 and 104 provided thereon, and the displacement of the operating piston, that is, the main valve 10
A stopper 105 is provided for mechanically adjusting the maximum valve displacement when the valve 1 is displaced. The setting of the maximum valve displacement is set so that the pressure loss at the main valve 101 is sufficiently small so that sufficient flow control can be performed by the motor variable speed operation even at the time of the descending operation and the 0% loading.

The operating piston 102 is connected to the pilot port 1
The piston rod side chamber 112 driven by the pilot flow from the pressure chamber 10 to the pressure receiving chamber 111 and opposed to the pressure receiving chamber 111
Is provided with a drain port 113 communicating with the tank 4.
Reference numeral 114 denotes a pump port that communicates with the flow path 222.

Next, the main valve section 40 during elevator operation
The control method of 0 and the valve operation will be described.

Stopped state The motor 2 and the fluid pressure pump 1 are stopped, and each pilot valve 10 is stopped.
6, 107 and 108 are de-energized. The spool of the two-way valve 300 has the minimum valve opening as described above. In this state, the cylinder pressure Pc is applied to the main valve 101.
, And only the force in the valve closing direction by the spring 103 acts, so that the valve is closed. Therefore, since the flow path 223 of the cylinder port, the flow path 222 of the pump port, and the tank 4 are shut off, the stop position of the car 201 is maintained.

(1) In the case of ascending operation FIG. 5 is a diagram for explaining the control sequence of FIG. 3 during the ascending operation, in which the car speed VC and the main valve opening Xm with respect to time t,
The relationship between the spool opening Xs and the motor excitation signal 501 is shown.

The electromagnetic switching valves 106, 10 of the check valve 100
7, 108 are not excited. Therefore, the main valve 101 operates in the same manner as a normal check valve. That is, the pressure of the pump port 222 is equal to the pressure of the cylinder port 223 and the spring 1
The valve opens when the pressure exceeds the sum of the pressures equivalent to the pressing force of 03, and closes when the pressure is less than the sum. The main valve opening Xm is substantially proportional to the flow rate.

When the motor 2 rotates in the ascending direction according to the motor rotation speed command of the control device 5, the pump pressure Pp rises by the fluid pressure pump 1 and the pressure in the flow path 222 of the pump port increases. Here, the spool 3 of the two-way valve 300
01 is the minimum valve opening X when the pump pressure Pp is equal to or higher than a predetermined pressure.
smin to the maximum valve opening Xsmax. At this time, the main valve 101 is still closed.

When the cylinder pressure Pc becomes substantially equal to the pump pressure Pp, the rotational speed of the motor 2 is controlled to a variable speed according to the speed command, and the pressure and flow rate of the fluid discharged from the fluid pressure pump 1 further increase. Open the valve 101 and open the two-way valve 30
0, the fluid 223 is supplied to the fluid cylinder 200, the plunger 204 rises, and as a result, the car 20
Increase 1

When the rotation speed of the motor 2 is stopped, the pump discharge flow rate decreases, the valve opening Xm of the main valve 101 moves in the closing direction, and when the pump discharge flow rate becomes zero, the main valve 101 is closed and the car 201 is closed. Stops. At this time, since the pump pressure Pp is equal to or higher than the predetermined pressure, the spool 301 still maintains the maximum valve opening Xsmax. Thereafter, the motor 2 is stopped. Then, when the pump pressure Pp decreases and falls below a predetermined pressure, the spool 301 reaches the minimum valve opening Xsmin.

(2) Case of descending operation FIG. 6 is a diagram for explaining the control sequence of FIG. 3 at the time of descending operation, in which the car speed VC and the main valve opening Xm with respect to time t are determined.
The relationship among the spool opening Xs, the motor excitation signal 501, and the excitation signals of the pilot valves 106, 107, 108 is shown. During the descent operation, the electromagnetic switching valves 106, 107 and 108 are controlled to forcibly open the main valve 101.

When the motor 2 rotates in the ascending direction according to the motor speed command from the control device 5, the pump pressure Pp rises by the fluid pressure pump 1 and the pressure in the flow path 222 of the pump port increases. Here, the spool 3 of the two-way valve 300
01 is the minimum valve opening X when the pump pressure Pp is equal to or higher than a predetermined pressure.
smin to the maximum valve opening Xsmax.

When the cylinder pressure Pc becomes substantially equal to the pump pressure Pp, the electromagnetic switching valves 106, 107 and 108 are excited. As a result, the main valve 101 starts opening. After that, the rotation speed of the motor 2 is changed according to the speed command, and the fluid of the fluid pressure cylinder 200 flows from the cylinder port 223 to the
Pump port 2 via directional valve 300 and check valve 100
22, is supplied to the fluid pressure pump 1, the plunger 204 descends, and as a result, the car 201 descends. When the rotation speed of the motor 2 is stopped, the flow rate from the fluid pressure pump 1 to the tank 4 decreases, and when the pump flow rate becomes zero, the car 201 stops.

Here, the electromagnetic switching valves 106, 107, 10
8 is released. As a result, the pilot pressure in the pilot chamber 111 is released to the tank, so that even if the pump port pressure Pp is the same as the cylinder pressure Pc, the spring 103
The main valve 101 is closed by the pressing force. At this time, since the pump pressure Pp is equal to or higher than the predetermined pressure, the spool 301 still maintains the maximum valve opening Xsmax. Thereafter, the motor 2 is stopped. Then, when the pump pressure Pp decreases and falls below a predetermined pressure, the spool 301 reaches the minimum valve opening Xsmin.

(3) In the event of an emergency such as a power failure during ascending operation In FIG. 5, when an emergency stop such as a power failure occurs at t = T1, the motor torque is lost. The brake is applied, and the rotation speed and flow rate become zero. Since the flow rate and the valve opening are proportional, the car is immediately braked without idle running. The strength of the brake is determined by the torque due to the inertia of the motor and the load pressure. But,
Since there is no free running, there is no overspeed in the ascending or descending direction. Therefore, the emergency stop shock is maintained at a sufficiently safe level without being greatly affected by the magnitude of the inertia of the motor.

(4) Case of Emergency such as Power Failure During Descent Operation In FIG. 6, it is assumed that the following emergency state such as power failure occurs at t = T2.

(41) In the case of a power failure, (42) the electromagnetic switching valve breaks down immediately before the power failure, and the check valve is kept open.
Each operation in the case of a power failure will be described with reference to FIGS. FIG.
FIG. 8 shows a spool opening (equivalent to the opening area) Xs and a check valve opening (equivalent to the opening area) of the two-way valve 300 during a power failure during a descent operation in the hydraulic elevator according to one embodiment of the present invention. FIG. 7 is a diagram for explaining the Xm, the car speed Vc, and the car acceleration αc.
Corresponding to

In the cases of (41) and (42), the following operation is performed.

Since the excitation of the electromagnetic switching valves 106, 107 and 108 is released, the pilot pressure drops and the main valve 101 closes. At this time, the electromagnetic switching valve 108 is delayed by the control device 5 to release the excitation. The specific means is, for example, charging a capacitor as disclosed in Japanese Patent Publication No. 05-132247.

Therefore, the pilot fluid uses the variable throttle 10
The valve 9 is released from the electromagnetic switching valve 108 to the tank.
Therefore, the valve is closed more slowly than during normal valve closing. Further, the variable aperture 109 is changed to Japanese Patent Publication 4-153171.
If the throttle area is changed according to the displacement of the operating piston 102 as in the publication, the valve closing speed can be initially increased according to the displacement of the operating piston 102, and can be changed slowly as it approaches the fully closed state. .

During this period, when the motor torque is lost and the pump pressure Pp decreases, an overspeed occurs. When the pump pressure Pp decreases to a predetermined pump pressure Pp ', the valve closing force acting on the pressure receiving chamber 306 decreases. And the valve opening force acting on the spring 3
It overcomes the sum of the valve opening forces of 03 and operates in the valve closing direction up to the minimum valve opening Xsmin. At this time, the check valve 101 has not been fully closed yet.

As a result, the flow from the hydraulic cylinder 200 to the hydraulic pump 1 is restricted by the two-way valve 300, so that the overspeed is limited and the car speed Vc is reduced. Therefore, the overspeed can be limited and it is safe.

Thereafter, the check valve 100 is fully closed. In this way, the flow rate is reduced in at least two stages with respect to time, so suddenly the check valve 1
The emergency stop shock at the time of an emergency such as a power failure can be suppressed as compared with the case where 00 is fully closed, and the vehicle is stopped with a short traveling distance.

In the case of (42), even if the check valve 100 is not closed, the overspeed is limited and the speed is reduced. Therefore, the overspeed can be suppressed to a certain level, and the minimum safety can be secured.

As described above, even when the pressure ratio is large,
Even if a check valve with an opening area large enough to obtain the rated speed during a 0% loading descent operation has an abnormality in motor control during descent operation, and a malfunction of the pilot valve Even if there is, it is possible to limit the overspeed during the descent operation even when the vehicle is fully loaded, and to safely stop the car even in an emergency such as a power failure.

[0078]

According to the present invention, even if the pressure ratio is increased, the overspeed can be suppressed by the two-way valve, and the emergency stop shock in the event of an emergency such as a power failure can be suppressed. Regardless of this, a fluid pressure elevator that can secure the rated speed is realized.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of a hydraulic elevator according to one embodiment of the present invention.

FIG. 2 is a view for explaining the structure of the two-way valve of FIG. 1 which is one embodiment of the present invention.

FIG. 3 is a diagram illustrating a hydraulic circuit according to an embodiment of the present invention.

FIG. 4 is a view for explaining the structure of a main valve section of FIG. 3 which is an embodiment of the present invention.

FIG. 5 is a diagram illustrating a method of controlling a rising operation of a hydraulic elevator according to an embodiment of the present invention.

FIG. 6 is a diagram illustrating a method of controlling the descent operation of the hydraulic elevator according to one embodiment of the present invention.

FIG. 7 is a diagram illustrating a two-way valve, a check valve, a car speed, and a car acceleration at the time of a power failure during a descent operation in the fluid pressure elevator according to one embodiment of the present invention.

FIG. 8 is a diagram illustrating a two-way valve, a check valve, a car speed, and a car acceleration at the time of a power failure during a descent operation in the fluid pressure elevator according to one embodiment of the present invention.

FIG. 9 is a diagram illustrating a fluid pressure elevator.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Fluid pressure pump, 2 ... Motor, 3 ... Filter, 4 ... Tank, 5 ... Control device, 6 ... Main relief valve, 7 ... Pilot relief valve, 8 ... Fixed throttle, 9 ... Electromagnetic switching valve, 10 ...
Electromagnetic switching valve (HALP valve), 11 stop valve, 12 check valve, 100 check valve, 101 main valve, 102 operating piston, 103 spring, 104 spring, 105 stopper, 106 electromagnetic Switching valve, 107: electromagnetic switching valve, 10
Reference numeral 8: electromagnetic switching valve, 109: variable throttle, 110: pilot port, 111: pressure receiving chamber, 112: piston rod side chamber, 113: drain port, 114: pump port, 2
00: fluid pressure cylinder, 201: car, 202: rope, 203: pulley, 204: plunger, 205:
Cylinder, 206 ... rope, 207 ... rope, 208 ...
Counterweight, 209: rope for encoder / pulley, 210: encoder / pulley, 211: encoder / pulley, 212: encoder, 220: pressure sensor,
221, a pressure sensor; 222, a flow path between the fluid pressure pump and the check valve; 223, a flow path between the check valve and the fluid pressure cylinder; 300, a two-way valve; 301, a spool;
... land, 302 ... valve body, 303 ... spring, 304 ...
Cylinder port, 305 pump port, 306 pressure receiving chamber, 307 pressure receiving chamber, 308 flow path, 309 flow path, 3
Reference numeral 10 denotes a stopper, 311 denotes a stopper, 312 denotes a seal member, 400 denotes a main valve portion, 401 denotes a valve body, 501 denotes a motor excitation signal, and 502 denotes an excitation signal of the electromagnetic switching valve 106.
503: excitation signal of the electromagnetic switching valve 107, 504: excitation signal of the electromagnetic switching valve 108.

Continuing on the front page (72) Inventor Katsuharu Shuto 1070 Ma, Hitachinaka City, Ibaraki Prefecture Inside the Mito Plant, Hitachi, Ltd. (72) Inventor Noboru Arahori 1070 Ma, Hitachinaka-shi, Ibaraki Pref.Hitachi, Ltd.Mito Plant (72) Inventor Satoru Sasaki 1-6-6 Kanda Nishikicho, Chiyoda-ku, Tokyo Co., Ltd.Hitachi Building System Co., Ltd.

Claims (5)

[Claims] 1. A flow rate of a fluid to be supplied to or discharged from a hydraulic cylinder is controlled by changing a rotation speed of a motor for driving a hydraulic pump, and the fluid is directly or indirectly supported on the top of the hydraulic cylinder. In a hydraulic elevator for controlling the speed of a car, a two-way valve that is not pre-closed is connected in series with a check valve provided between the hydraulic cylinder and the hydraulic pump, and its opening is set during normal running. Is a maximum valve opening, and a minimum valve opening in an emergency such as when an overspeed occurs during a descent or when a power failure occurs during a descent. 2. The hydraulic elevator according to claim 1, wherein the two-way valve provided in series with the check valve comprises a two-way valve.
A hydraulic pressure elevator having a plurality of pressure receiving chambers, each of which is provided with a stopper for guiding a cylinder pressure and a pump pressure, and for adjusting a minimum valve opening of a two-way valve on the pressure receiving chamber side guiding the pump pressure. . 3. The fluid pressure elevator according to claim 1, wherein the two-way valve is closed from a maximum valve opening degree to a minimum valve opening operation in an emergency such as a power failure during a descent operation. Slower hydraulic elevator operating to valve opening. 4. The fluid pressure elevator according to claim 1, wherein the non-return valve includes the non-return valve and the two-way valve in a process of fully closing the non-return valve in an emergency such as a power failure during a descent operation. A hydraulic elevator that changes the total flow area of two valves in two or more stages. 5. The check valve according to claim 1, further comprising a main valve and an external drain type operation piston, wherein a pressure and a flow rate of a pressure receiving chamber of the operation piston are controlled by three electromagnetic switching valves. One is an electromagnetic switching valve disposed in a flow path between the cylinder pressure and the operation piston chamber, and the other two is an electromagnetic switching valve disposed in a flow path between the operation piston chamber and the tank, and the other two are A fluid pressure elevator having a variable throttle in a flow path provided with at least one of the electromagnetic switching valves.