JPS6153310B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a hydraulic system that has many advantages, such as greatly reducing power consumption, allowing for larger size, lower noise, less temperature rise of hydraulic oil, and high safety. Regarding elevators.

The present inventor previously developed a ram-type hydraulic elevator in which the ram is raised and lowered by driving the jack of the ram with an electric motor via a variable displacement hydraulic pump. The hydraulic oil is transferred to the jack by driving a variable displacement hydraulic pump whose capacity is adjusted to send hydraulic oil to the jack, and when the ram is lowered, the variable capacity is adjusted to remove hydraulic oil from the jack. A system has been provided in which a capacity type hydraulic pump is driven by the falling energy of an elevator, and the induction generator is forcibly driven by the drive of the pump, so that it works as an induction generator.

According to this method, most of the falling energy of the elevator when descending is recovered as electric power generated by the induction motor that works as an induction generator, and this can be returned to the power source, making it possible to save a large amount of electric energy. ing.

However, the above method requires a variable displacement hydraulic pump and a variable displacement device for varying the displacement, and these devices are extremely expensive compared to the fixed displacement hydraulic pump used in the present invention, and It is difficult to increase the capacity of the hydraulic pump,
The disadvantage is that large hydraulic elevators cannot be manufactured.

The present invention aims to eliminate such drawbacks, and uses a hydraulic pump driven by an electric motor to transfer hydraulic fluid from a tank to a jack and from the jack to a tank to raise and lower an elevator. In a hydraulic elevator, a fixed-displacement hydraulic pump is used for the hydraulic pump, and a cage-type induction motor is used as the electric motor, and when the elevator is going down, this is operated as an induction motor, and the generated electric power is converted into a power source. The hydraulic circuit of the elevator is equipped with an electronically controlled variable flow rate solenoid valve that sets the hydraulic oil flow rate according to each stage of the elevator: stop, slow rise, full speed rise, slow fall, and full speed fall. When the hydraulic oil flow rate deviates from the set value, a flow meter installed in the hydraulic circuit detects the deviation from the set value in the hydraulic oil flow rate as a feedback signal, and uses this feedback signal to control the electronically controlled flow rate to regulate the hydraulic oil flow rate to the set value. The desired results were achieved by automatically adjusting the opening and closing of the solenoid valve.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to explain the hydraulic elevator of the present invention in more detail below, the hydraulic elevator of the present invention will be described in detail based on embodiments shown in the accompanying drawings.

Embodiment 1 FIG. 1 shows a first embodiment of a hydraulic elevator according to the present invention, in which hydraulic oil is transferred from a tank 3 to a jack 4 by a constant displacement hydraulic pump 2 driven by a cage-type induction motor 1. This is a ram-type hydraulic elevator in which the elevator is moved up and down by moving the ram 5 of the jack 4 up and down.

The hydraulic elevator of the present invention is equipped with electronically controlled variable flow rate solenoid valves 6 and 7 in its hydraulic circuit to set the hydraulic oil flow rate corresponding to each stage of elevator stop, slow rise, full speed rise, slow fall and full speed fall. are doing.

Also, if the above hydraulic oil flow rate deviates from the set value,
A flow meter 8 installed in the hydraulic circuit detects deviation of the hydraulic oil flow rate from a set value as a feedback signal, and an electronically controlled variable flow rate solenoid valve 6 is used to regulate the hydraulic oil flow rate to the set value based on this feedback signal. , 7 are configured to automatically adjust the opening and closing of the openings.

The operating functions of this hydraulic elevator will be sequentially explained below for each stage of the elevator: stop, slow rise, full speed rise, slow fall, and full speed fall.

A Stop stage of the elevator: The power to the cage-type induction motor 1 shown in FIG.
The control voltage V of is zero, the former is completely open,
The latter is completely closed.

Therefore, the hydraulic oil is not transferred from the tank 3 to the jack 4, and the movement of hydraulic oil from the jack 4 to the tank 3 due to the free fall of the elevator is also prevented by the check valve 9, so that the elevator is completely closed. is in a stopped state.

B: Slow rise (accelerated rise) stage of the elevator; Start the cage-type induction motor 1 shown in FIG. 10 and is transferred to the hydraulic circuit 11.

When the electric motor 1 is started, the electronically controlled variable flow rate solenoid valve 6 for lift is fully open, and the hydraulic oil is returned to the tank 3 through the variable flow rate solenoid valve 6. Hydraulic pressure is not generated to raise it.

The variable flow rate solenoid valve 6 is operated according to an electronic control program shown in FIG. 2, and the vertical axis indicates the control voltage V or current I for electronically controlling the variable flow rate solenoid valve 6. The horizontal axis indicates the moving distance x or time t of the elevator.

As shown in FIG. 2, when the electric motor 1 is started (x=0 or t=0 position), the voltage V is zero and the variable flow rate solenoid valve 6 is fully open, and as the voltage V increases in the positive direction, Accordingly, the variable flow rate solenoid valve 6 is configured to gradually close.

Therefore, when the variable flow rate solenoid valve 6 is operated according to the program section B for the slow speed increase stage in FIG. Since all the transferred hydraulic oil is returned to the tank 3, no hydraulic pressure is generated in the jack 4 to raise the ram 5, but as the control voltage V of the variable flow rate solenoid valve 6 increases, the valve 6 gradually closes. The flow rate of hydraulic oil transferred to the jack 4 through the check valve 9 increases, and hydraulic pressure is generated to raise the ram 5.

The rising speed of the ram 5 is accelerated as the voltage V increases, causing the elevator to rise at a slow speed in an accelerated manner.

C Full-speed rising phase of the elevator; When the variable flow rate solenoid valve 6 is operated according to the program section C for the full-speed rising phase in Fig. 2, the voltage V is held constant at the maximum voltage Vc, so the flow rate is variable. The solenoid valve 6 is held completely closed or slightly open,
The elevator, which has been accelerated during the slow ascent stage, will ascend at a constant speed.

The full-speed rise speed of the elevator mentioned above can be adjusted to an appropriate value, and the maximum voltage for that speed
This is done by setting Vc appropriately.

B' Slow rise (decelerated rise) stage of the elevator; When the elevator rises at full speed to the position x ₁ directly below the target stop floor, a deceleration signal is input to the variable flow rate solenoid valve 6, that is, the valve 6 is activated in the program section B of Fig. 2. ’.

The voltage V decreases from the maximum voltage Vc, and accordingly, the variable flow solenoid valve 6 opens, the flow rate of hydraulic oil transferred to the jack 4 decreases, and the ascending speed of the elevator decreases.

While decelerating, the elevator ascends to the stop position x ₂ of the target floor and stops.

At this time, the electric motor 1 continues to rotate for several seconds even after the elevator reaches the stop position _x2 , and then stops.

As described above, the elevator of the present invention operates extremely smoothly according to the program shown in FIG. 2 from start to acceleration up, constant speed full speed up, deceleration up, and stop.

D Slow descent (accelerated descent) phase of the elevator; The electronically controlled variable flow rate solenoid valve 7 for descent is operated by the program section D for the slow descent phase of the electronic control program shown in FIG. 7 is configured to gradually open as the control voltage V increases in the negative direction.

Simultaneously with the operation of the variable flow rate solenoid valve 7, the electromagnetic check valve 13 installed in the pilot circuit 12 of the electronically controlled variable flow rate solenoid valve 6 for ascending operates, opening the check valve 13 and closing the pilot circuit 1.
2 to close the electronically controlled variable flow rate solenoid valve 6 for rising, the variable flow rate solenoid valve 7 operates according to the program section D in FIG. 2, and the voltage V changes in the negative direction. When the valve 7 gradually opens as the pressure increases, the hydraulic oil flows from the jack 4 through the variable flow rate solenoid valve 7 to the fixed displacement hydraulic pump 2 and the electric motor 1 of the elevator due to the gravity applied to the elevator. It is transferred to the tank 3 while being rotated in the opposite direction to the direction in which it was raised.

As the voltage V increases in the negative direction, the elevator descends at a slow speed, and the constant displacement hydraulic pump 2 is driven by the falling energy.

When the elevator descends to any point between the stop position x ₂ and the x ₃ position (the point in time when the flow of hydraulic oil returning from the jack 4 to the tank 3 due to the rotation of the electric motor 1 is at its maximum, that is, at the maximum descending speed), cage-type induction occurs. Electric motor 1
This squirrel cage induction motor 1 is energized and operated.
is forcibly driven by the hydraulic pump 2 and works as an induction generator, so that the falling energy of the elevator can be converted into electric power generated by the induction generator.

E full speed down phase of the hydraulic elevator; when the variable flow solenoid valve 7 is actuated according to the program section E for the full speed down phase of FIG. 2, the voltage V is held constant at the maximum voltage -Ve; The variable flow rate solenoid valve 7 is held in a fully open or slightly closed state, and the elevator is accelerated in the slow descent stage, and then descends at full speed at a constant speed, and this falling energy drives the constant displacement hydraulic pump 2. The cage-type induction motor 1, which functions as an induction generator, is driven through the motor to generate electric power.

The full-speed descending speed of the elevator can be set to an appropriate value, and this is done by appropriately setting the maximum voltage -Ve to minimize the resistance of the variable flow rate solenoid valve 7 and the flow rate of hydraulic oil passing through the valve 7. Needless to say, is set within a range that is greater than the flow rate of the hydraulic oil returned to the tank 3 by the hydraulic pump 2.

D' Slow descent (deceleration descent) phase of the elevator; When the elevator descends at full speed to the x ₄ position, a deceleration signal is input to the variable flow rate solenoid valve 7, that is, the valve 7 operates according to the program section D' in Fig. 2. I come to do it.

As the absolute value of voltage V decreases from the maximum voltage Ve, variable flow rate solenoid valve 7 closes and jerks 4.
The flow rate of hydraulic oil transferred from the elevator to the tank 3 decreases, the descending speed of the elevator decreases, and the elevator stops at the stop position _x5 .

At this time, the electric motor 1 is turned off between X ₄ and X ₅ (at the time when it starts to decelerate beyond x ₄ ), and the voltage of the electromagnetic check valve 13 is also turned off.

As described above, the elevator of the present invention has
The vehicle operates extremely smoothly according to the electronic control program shown in FIG. 2, from constant speed full speed descent to deceleration descent.

As described above, the elevator of the present invention rises in response to each stage of elevator stop, slow rise B, B', full speed rise C, slow fall D, D', and full speed fall E in the electronic control program shown in FIG. The hydraulic oil flow rate flowing through the electronically controlled variable flow rate solenoid valve 6 for lowering or the electronically controlled variable flow rate solenoid valve 7 for lowering is configured to be set, and when the elevator is stopped, ascends or descends, the hydraulic pump and piping If the hydraulic oil flow rate deviates from the set value due to the elevator rising or falling rapidly due to an unexpected failure of the electric motor or valve, the flow meter 8 detects this deviation from the set value of the hydraulic oil flow rate as a feedback signal. Based on this feedback signal, the opening and closing of the electronically controlled variable flow rate solenoid valve 6 for ascending or the electronically controlled variable flow rate solenoid valve 7 for descending can be automatically adjusted in order to regulate the hydraulic oil flow rate to the set value. This makes the process even smoother and is equipped with extremely excellent safety equipment.

Furthermore, since the safety device uses an electronically controlled variable flow rate solenoid valve, it has significantly faster response and higher reliability than the mechanical safety device that has been commonly used in conventional hydraulic elevators.

The safety device used in the hydraulic elevator of the present invention works extremely effectively in the following failures.

b) When the power goes out while the elevator is running.

(b) When the motor is disconnected even though it is energized.

C. When the coupling between the electric motor and hydraulic pump breaks down.

(d) When the piping is disconnected.

E When the control voltage is normal and the drive side power supply is defective.

The hydraulic elevator of the present invention can prevent noise and can significantly reduce the pressure loss of the variable flow rate solenoid valves 6, 7.

Furthermore, the hydraulic elevator of the present invention recovers the falling energy of the elevator when it descends as electric power generated by the cage-type induction motor 1 which operates as an induction generator via the constant displacement hydraulic pump 2, and returns it to the power source. You can save a lot of power, but
By reducing the pressure loss in the variable flow rate solenoid valves 6 and 7, power can be saved more effectively.

In conventional hydraulic elevators, most of the falling energy of the elevator is converted into heat, which increases the temperature of the hydraulic oil, but in the hydraulic elevator of the present invention, the falling energy of the elevator can be converted into electric power and recovered, so that heat can be recovered. It is possible to significantly reduce the occurrence of oil temperature rise of hydraulic oil.

Furthermore, the hydraulic elevator of the present invention uses a constant displacement hydraulic pump 2,
Since the capacity of the hydraulic elevator can be increased, it is possible to manufacture a large hydraulic elevator, and it can be manufactured at a low cost.

The hydraulic elevator of the present invention is equipped with a manual on-off valve 14 for safety confirmation, and when a descending signal is applied to the variable flow rate solenoid valve 7 with the electric motor 1 powered off during periodic inspection, the manual on-off valve for safety confirmation is activated. 14
When the elevator is opened and the elevator is allowed to fall rapidly, it can be checked whether the resting device is working properly.

The safety confirmation manual on-off valve 14 is useful not only during periodic inspections but also during inspections and adjustments at the site where the elevator is installed, and allows for easy on-site adjustment of the elevator.

In the embodiment (1) of FIG. 1, 15 is a relief valve that determines the maximum pressure of the hydraulic oil, 16 is a check valve for preventing negative pressure, 17 is a filter, and 18 is a pressure gauge.

Embodiment (1) of the hydraulic elevator of the present invention has been described above. In this embodiment 1, the electric motor 1 is configured to rotate in the normal direction when the elevator is ascending and to rotate in the reverse direction when the elevator is descending.

Next, FIG. 3 shows an embodiment (2) of a hydraulic elevator according to the present invention, in which the electric motor 1 is configured to rotate in the normal direction both when the elevator is ascending and when it is descending.

The operating functions of the hydraulic elevator of Example (2) will be explained below.

The hydraulic elevator is the second one as in the case of Example (1).
It operates according to the electronic control program shown in the figure.

The time when the elevator goes up is the same as in Example (1), so it will be omitted.

When the elevator descends, the electronically controlled variable flow rate solenoid valve 7 for descending operates according to the program sections D, E, and D' in Fig. 2, and as the elevator descends, the hydraulic oil is supplied from the jack 4 to the corresponding one. is transferred to the hydraulic circuit through valve 7, and is transferred to tank 3.
The transferred hydraulic fluid is prevented from moving to the fixed displacement hydraulic pump 2 by the check valve 16'.
It moves to the hydraulic circuit 11 while driving.

At this time, the control voltage of the electronically controlled variable flow rate solenoid valve 6 for lifting is zero and the valve 6 is fully open, so the hydraulic oil that has moved to the hydraulic circuit 11 passes through the variable flow rate solenoid valve 6 to the tank 3. will be transferred to.

The direction of rotation of the constant capacity hydraulic pump 2 is forward rotation, the same as when the elevator is ascending, and therefore the cage-type induction motor 1, which operates as an induction generator, also rotates forward to generate electric power.

In the embodiment (2) of FIG. 3, the hydraulic circuit consisting of the pilot type safety valve 20 and the spring offset type switching valve 21 installed in this pilot circuit is a hydraulic circuit for reducing back pressure, and when the elevator is lowered, the switching valve is 21 is operated from the rest position to the operating position to perform its function.

[Brief explanation of the drawing]

FIG. 1 is an embodiment of the hydraulic elevator of the present invention.
(1), FIG. 2 is a diagram showing an electronic control program used in the hydraulic elevator of the present invention, and FIG. 3 is a hydraulic circuit diagram showing embodiment (2) of the hydraulic elevator of the present invention. They are respectively expressed. 1...Cage-type induction motor, 2...Fixed displacement hydraulic pump, 3...Tank, 4...Jacket, 5...
Ram, 6... Electronically controlled variable flow rate solenoid valve for ascending, 7... Electronically controlled variable flow rate solenoid valve for descending, 8... Flow meter, 9... Check valve, 10...
...Suction filter, 13...Solenoid check valve, 14
... Manual on-off valve for safety confirmation, 15 ... Relief valve, 16 ... Check valve for negative pressure prevention, 17 ... Filter, 18 ... Pressure gauge.

Claims (1)

[Claims] 1. Hydraulic oil is transferred from a tank to a jack and from the jack to a tank by a hydraulic pump driven by an electric motor to move the elevator up and down, and a fixed displacement hydraulic pump is used as the hydraulic pump. , and a hydraulic elevator in which a cage-type induction motor is used as the electric motor and is operated as an induction generator when the elevator is lowered, and the generated power is returned to the power source. Equipped with an electronically controlled variable flow rate solenoid valve that sets the hydraulic oil flow rate in response to each stage of stop, slow rise, full speed rise, slow fall, and full speed fall, and installed in the hydraulic circuit when the hydraulic oil flow rate deviates from the set value. The flow meter detects the deviation of the hydraulic oil flow rate from the set value as a feedback signal, and this feedback signal automatically adjusts the opening and closing of the electronically controlled variable flow rate solenoid valve to regulate the hydraulic oil flow rate to the set value. A hydraulic elevator characterized by: 2. The hydraulic elevator according to claim 1, wherein the electric motor rotates in the normal direction when the elevator is ascending and reversely rotates when the elevator is descending. 3. The hydraulic elevator according to claim 1, wherein the electric motor rotates normally when the elevator ascends and also rotates normally when the elevator descends.