JPH0534272B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention supplies and discharges pressure oil to and from a cylinder of a hydraulic ram through a flow control valve, and moves a plunger of the hydraulic cylinder up and down to raise a car. and a lowering hydraulic elevator, particularly the structure of the flow control valve.

[Background of the invention]

Conventional hydraulic elevators of this kind have been provided with flow rate control valves for ascending and descending in order to move the plunger of the hydraulic cylinder up and down, and also provided with a check valve for the purpose of preventing leakage of pressure oil. In addition, the speed control of raising and lowering the car was performed using a main valve, a pilot valve, and a restrictor installed in a flow path connecting these two valves, so the structure and control method were complicated. However, since the running characteristics of the elevator change depending on the operating conditions of the elevator, this has the disadvantage of making the ride uncomfortable for passengers.

[Purpose of the invention]

In view of the above, it is an object of the present invention to provide a hydraulic elevator with excellent controllability and economy using a simple and compact flow control valve.

[Summary of the invention]

In order to achieve the above object, the present invention provides a hydraulic elevator that raises and lowers a car by supplying and discharging pressure oil to and from a cylinder of a hydraulic ram through a flow control valve, in which the flow control valve is disposed within a valve body. The structure houses each main control valve for ascending and descending, each pilot valve, and a reverse switching valve, and corresponds to the operating conditions of the hydraulic elevator.The pulse train drive current has a pulse width proportional to the operating command signal. By driving the pilot valve at
The present invention is characterized in that it is configured to control each main control valve corresponding to each pilot valve.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram showing the basic configuration of this embodiment.
A is a hydraulic source, B is a flow control valve, and C is a hydraulic cylinder.
The hydraulic ram consists of Ca and plunger Cb, and D is the elevator car. When raising the car D, the hydraulic source A is driven to supply pressure oil to the hydraulic cylinder Ca, and the plunger Cb is pushed up to raise the car D. When lowering the car D, the pressure oil is discharged from the hydraulic cylinder Ca and the car D is lowered in the opposite manner to the above. In this case, the flow rate control valve B controls the flow rate of the pressure oil, and the hydraulic ram C controls the raising and lowering of the car D.

The details of the flow rate control valve B are as shown in the sectional view shown in FIG. That is, the flow rate control valve B includes a valve body 10 having ports 10a to 10c.
Main control valves 20 and 30 for ascending and descending,
Pilot valves 80a, 80b and 90a, 90 control these main control valves 20, 30, respectively.
b, and a check valve 40 provided between the ports 10a and 10b are integrated.
The ports 10a to 10c are hydraulic power source A in FIG.
Each is connected to a hydraulic cylinder Ca and an oil tank (not shown).

The above main control valve 20 for rising is connected to the port 10.
A skirt 21 inserted into the communication path 11a between a and 10c and provided with a notch 21b through which hydraulic pressure flows.
b, a spool 22 integrally formed with the poppet 21, a sleeve 23 into which the spool 22 is inserted and slidably provided on the upper wall of the valve body 10; a stopper 24 that is attached to a wall and limits the stroke range of the poppet 21; and a stopper 24 that limits the stroke range of the poppet 21;
1 and a spring 25 interposed between the lower wall of the valve body 10. The main control valve 20 for rising is installed between the ports 10a and 10c, and controls the flow rate of pressure oil between both ports.

The poppet 21 is housed in an oil chamber 27 communicating with the port 10a so as to be movable up and down.
When the poppet 21 moves up and down, the valve body 1
Since the opening area of the notch 21b of the skirt 21a changes due to the valve seat 26 provided at 0, the opening area of the communication path 11a through which the pressure oil flows also changes. In this case, the spool 22 also moves up and down together with the poppet 21, thereby blocking or switching communication between the oil passages 23a and 23b provided in the sleeve 23.

On the other hand, by changing the relative position of the sleeve 23 with respect to the valve body 10, the displacement of the poppet 21 and the timing of switching between the oil passages 23a and 23b are adjusted. Also, the poppet 21 is connected to the oil chamber 27.
The hydraulic pressure acting on the poppet 21 is driven by the force of the spring 25 and the hydraulic pressure acting on the oil chamber 28 in the poppet 21. The oil pressure in the oil chamber 28 is controlled by the pilot valve 80.
a, 80b.

The pilot valves 80a and 80b have the same structure. That is, one of them 80a is the valve body 81
A ball 82a and a ball 82 are placed in a valve chamber 81a provided inside the valve chamber 81a.
A solenoid 84a and a core 85 are housed outside the valve body 81.
It is configured by providing a. In such a pilot valve 80a, since the ball 82a is normally pushed up by the force of the spring 83a, the flow paths 89a and 8
7a is in communication, but when the solenoid 84a is energized, the core 85a is attracted and lowered.
The ball 82a is pressed against the valve seat 86a and breaks communication between the flow paths 89a and 87a.

The other pilot valve 80b has the same structure as the above-mentioned pilot valve 80a and performs the same function, so a description thereof will be omitted. The valve chamber 81a of the pilot valve 80a communicates with the port 10c of the valve body 10 through a passage 89a, and also communicates with the oil passage 23a of the spool 23, the oil chamber 28 in the poppet 21, and the throttle through a passage 87a. The ports 10a of the valve body 10 are communicated through valves 88, respectively. On the other hand, the valve chamber 81b of the pilot valve 80b communicates with the valve chamber 81a via a passage 89b, and also communicates with the oil passage 23 of the spool 23 via a passage 87b.
It communicates with b.

The check valve 40 has a poppet 41 that opens and closes a communication path 11c between the ports 10a and 10b of the valve body 10.
It is composed of a rod 42 directly connected to this poppet 41 and inserted into a guide groove 44 provided on the upper wall of the valve body 10, and a spring 43 interposed between the upper wall and the poppet 41. There is. Such a check valve 40 is housed in an oil chamber 45 that communicates with the port 10b, and is connected to the poppet 41.
is normally pressed against a valve seat 46 provided in the valve body 10 by the force of a spring 43, and prevents pressure oil from flowing from the port 10b side to the port 10a side.
When the pressure on the port 10a side becomes higher than the pressure on the port 10b side, the poppet 41 is pushed up against the force of the spring 43, so that the pressure oil flows from the port 10a side to the port 10b side.

The descending main control valve 30 differs from the ascending main control valve 20 only in that a spring 35 is provided in the oil chamber 38 in the poppet 31, and the other structures are the same, and its operation is also the same. The explanation will be omitted from here. This descending control valve 30 is housed in an oil chamber 37 that communicates with the port 10b of the valve body 10, and the skirt 31a of the main control valve 30 is connected to the port 10b.
It is inserted into the communication path 11b between and 10c.

Pilot valve 90 that controls the main control valve 30
One of the pilot valves 90a and 90b is different from the pilot valve 80a in that the flow passage 96 communicating with the valve chamber 91a is communicated with the passage 77 via the throttle valve 99.
The only difference is that the other structures are the same. Further, the other pilot valve 90b has the same structure as the pilot valve 80b, and the functions of both pilot valves 90a and 90b are also the same as that of the pilot valve 80b.
Since it is the same as 0a and 80b, the explanation will be omitted.

The pilot valves 80a, 80b, 90a, 9
0b applies a drive current having a pulse width proportional to the command signal to the solenoids 84a, 84b, 94.
It operates by applying voltage to a and 94b. That is, as shown in FIG. 3a, the values of the triangular wave signal G with period T and the command signal E or F are compared, and the value of the triangular wave signal G when the command signal E or F crosses the triangular wave signal G is calculated. Figure b corresponds to the valley width.
A pulsed current is applied to the solenoid 84 as shown in FIG.
a, 84b, 94a, 94b. Only when these solenoids are energized,
Cores 85a, 85b, 95a, 95b are shown in Figure 3c.
, and at other times, the spring 8
Ball 82a, by the force of 3a, 83b, 93a, 93b,
82b, 92a, 92b are pushed up. In this way, the pilot valves 80a, 80b, 90a,
90b performs ON-OFF operation.

Therefore, if the command signal E changes to F as shown in Figure 3a, the current pulse Ea applied to the solenoid will change to the current pulse width as shown in Figure 3b.
Fa, the width Eb of the core displacement changes to Fb as shown in c in the same figure. As a result, the output flow rate Q changes from Ec to Fc.

Next, the operation of this embodiment having the above-mentioned flow rate control valve B will be explained.

When the elevator is ascending, high-pressure oil is generated by operating hydraulic source A, and this high-pressure oil is passed through flow control valve B.
When supplied to the port 10a of the rise main control valve 2
0 through the opening of the notch 21b and the port 10
It is returned to the tank from c. In this case, a constant pressure is generated in the oil chamber 27 depending on the relationship between the supply flow rate of the pressure oil and the opening area of the notch 21b. The magnitude of this pressure can be freely selected by adjusting the opening area of the notch 21b via the stopper 24.

On the other hand, the pressure oil also flows into the oil chamber 28 and the valve chamber 81a of the pilot valve 80a through the throttle 88 and the flow path 87a, but since the pilot valve 80a is in the open state, this pressure oil flows through the flow path 89a. port 10c
It is returned to the tank.

Next, when a pulse current having a width proportional to the command signal for lifting is applied to the pilot valves 80a and 80b, it flows through the flow path 87a and reaches the port 10.
The flow rate discharged from c decreases, and the pressure oil flows into the oil chamber 28.
A larger amount flows into. Since the poppet 21 is pushed down by the hydraulic pressure acting on the oil chamber 28 against the force of the valve 25, the opening area of the notch 21b is reduced, and the flow rate is also reduced. As a result, the check valve 40 is opened due to an increase in the hydraulic pressure in the oil chamber 27, so that pressurized oil is supplied from the port 10b to the cylinder Ca (FIG. 1) of the hydraulic ram. When the poppet 21 is seated on the valve seat 26, the entire amount of pressure oil supplied from the hydraulic source A flows into the cylinder Ca, so the car D rises at full speed.

In response to the deceleration command signal, the pilot valve 80
When the pulse width of the current applied to b is reduced, the pilot valve 80b is opened for removal, so that the pressure oil in the oil chamber 28 flows through the flow paths 87a, 23a, 23b,
It passes through 87a, 89b, and 89a and is discharged from port 10c. Therefore, the poppet 21 gradually rises due to the force of the spring 25 and the hydraulic pressure in the oil chamber 27, and the opening area of the notch 21b provided in the skirt 21a increases, so that the amount of pressure oil supplied from the hydraulic source A is reduced. Car D decelerates because a portion of it bleeds off to the tank.

As the poppet 21 rises, the edge portion 22a of the spool 22 increases the fluid resistance between the flow paths 23a and 23b, and the force of the spring 25 and the hydraulic pressure in the oil chamber 27 and the hydraulic pressure in the oil chamber 28 are balanced. At this point, the poppet 21 stops. For this reason, the notch 2
Since the opening area of 1b is constant and a constant amount of pressure oil is discharged from port 10c to the tank, car D rises at a constant low speed.

Then, when the pulse width of the current applied to the pilot valve 80a is reduced by a stop command signal,
Pressure oil in the oil chamber 28 of the poppet 21 is discharged from the port 10c via the flow path 87a, the valve chamber 81a, and the flow path 89a. Therefore, the poppet 21 is pushed up by the force of the spring 25 and the hydraulic pressure of the oil chamber 27, the opening area of the notch 21b increases, and the entire amount of pressure oil from the port 10a is discharged from the port 10c. Therefore, the poppet 41 of the check valve 40 is seated on the valve seat 46 by the force of the spring 43,
Pressure oil enters the hydraulic ram cylinder Ca from port 10b.
Since there is no supply to car D, car D stops. At this time, by seating the poppet 41 on the valve seat 46,
It is possible to prevent the pressure oil inside the cylinder Ca from leaking.

The case of descending the elevator is similar to the case of ascending, and when a pulse current having a width proportional to the descending command signal is applied to the pilot valves 90a and 90b, the flow path 96 opens to the port 10c via the flow path 77. As the pressure decreases, the pressure oil in the oil chamber 38 of the poppet 31 flows through the flow paths 96 and 77 to the port 1.
It is discharged to the tank from 0c. On the other hand, the load pressure of the oil chamber 37 pushes up the poppet 31 against the working pressure of the oil chamber 38 and the force of the spring 35, and the notch 31
10 from port 10b by increasing the opening area of port 10b.
Increase the flow rate to c, i.e. the discharge flow rate to the tank. Therefore, the car D accelerates downward, and when the poppet 31 comes into contact with the stopper 34, the opening area of the notch 31b becomes maximum, so the car D descends at full speed.

In response to the deceleration command signal, the pilot valve 90
When the pulse width of the current applied to b is reduced, the flow path 98 is closed and the pressure in the oil chamber 38 increases, so the poppet 31 gradually descends and the opening area of the notch 31b decreases. Therefore, the flow rate of oil discharged from the cylinder Ca of the hydraulic ram decreases, and the car D decelerates. The poppet 31 descends, and the edge portion 32a of the spool 32 closes the oil passage 3.
The fluid resistance between 3a and 33b increases, and the poppet 31 stops at the point where the force of the spring 35, the hydraulic pressure in the oil chamber 38, and the hydraulic pressure in the oil chamber 37 are balanced. Therefore, the opening area of the notch 31b is constant, and a constant amount of pressure oil is discharged from the port 10c to the tank, so that the car D descends at a constant low speed.

Then, when the pulse width of the current applied to the pilot valve 90a is reduced by a stop command signal,
Since the pressure in the oil chamber 38 of the poppet 31 increases due to the closing of the flow path 96, the poppet 31
and the hydraulic pressure of the oil chamber 38. Therefore, the poppet 31 is seated on the valve seat 36,
Since the discharge of pressure oil from the cylinder Ca to the tank is stopped, the car D is stopped. The running waveform of the car at this time is as shown by the solid line H in FIG.

According to this embodiment, since the number of throttle resistances in the pilot system is the minimum, almost constant running characteristics can be obtained regardless of changes in elevator operating conditions (changes in oil temperature and pressure). However, since a throttle resistor is used in the main control valve, there is a risk that the running characteristics may change if the operating conditions vary greatly. That is, as shown by broken lines J and K in FIG. 4, there is a risk of deviation from the target solid line H. The broken lines J and K show the running characteristics when the deceleration increases and when the deceleration decreases, respectively. In such a case, the elevator ride becomes uncomfortable, which is not preferable.

However, in this embodiment, good running characteristics can be obtained even in the above case. That is, as described above, since the pilot valve is capable of controlling the flow rate approximately proportional to the specified current, it is possible to correct the above-mentioned fluctuations in the running characteristics.

FIG. 5 is a block diagram showing an example of a method for performing the above correction. In the same figure, 1 and 2 are oil temperature sensors and pressure (load) installed in the elevator.
The sensor corrects the pilot valve command signal based on the sensor signal. Reference numeral 3 denotes an operating device that issues commands to raise and lower the elevator, and 4 a comparison device, which compares the detected values from the oil temperature sensor 1 and the pressure sensor 2 based on the commands from the operating device 3.
The operating conditions are determined and the results are sent to the correction/pulse device 6. Reference numeral 5 denotes a cooling signal generating device, which generates an elevator speed pattern based on a command from the operating device 3.

The correction/pulse device 6 corrects the signal from the command signal generator 5 based on the determination result from the comparator 4, converts the correction result into a pulse train, and sends the pulse train to the solenoid of the pilot valve. The correction method is as follows.

First, when the deceleration increases as indicated by the broken line J in FIG. 4, the command signal is changed to a larger value as indicated by the broken line M in FIG. 6, and vice versa. When the deceleration becomes small as in
The command signal is changed so that it becomes smaller as indicated by the broken line N shown in FIG. The reason why the broken lines J and K deviate from the solid line H of the target characteristics is that there is a certain tendency in response to changes in oil temperature and pressure. All you have to do is input the temperature, pressure, and correction coefficient.

For example, in the case of a rise, when the oil temperature becomes high or the load becomes large, the acceleration increases at the valve speed as shown by the broken line J (Fig. 4), and conversely, in the case of a fall, the acceleration increases as shown by the broken line K. Acceleration decreases during deceleration. For the command signal corrected in this way, if the pulse width ΔT is changed and applied to the pilot valve solenoid as shown in Figure 3b, the running characteristics of the elevator will match the target characteristics shown by the solid line H in Figure 4. Become. Therefore, according to this embodiment, it is possible to keep the running characteristics constant against fluctuations in oil temperature and load pressure, and to easily correct even when the range of fluctuations is very large. be.

In the above embodiment, the balls 82 and 92 were housed in the valve chambers 81 and 91 of the pilot valves 80 and 90, but
Instead, in other embodiments shown in FIGS. 7a and 7b, namely pilot valves 80X and 90X, the valve chamber 8
The only difference is that the spools 100 and 101 are housed in the spools 1 and 91, respectively, and the other structures are the same. With this configuration, the spool 10
The forces acting on 0 and 101 are only the force of the spring 83 and the electromagnetic force of the solenoid 84, and the force of the spring 93 and the electromagnetic force of the solenoid 94, respectively, and the unbalanced hydraulic force becomes zero. Therefore, solenoid 8
The forces required for springs 4 and 94 are the same as those for springs 83 and 94, respectively.
93, which has the advantage of being relatively small.

〔Effect of the invention〕

As explained above, according to the present invention, the structure of the flow control valve is simplified and made more compact, and fluctuations in control characteristics due to fluctuations in oil temperature and pressure are reduced, thereby improving the controllability and economy of hydraulic elevators. can improve sex. Further, since it can be easily corrected in response to changes in load and oil temperature, it is possible to improve riding comfort.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of the basic configuration of an embodiment of a hydraulic elevator according to the present invention, Fig. 2 is a sectional view of a flow control valve of the same embodiment, and Fig. 3 a, b, and c are pilot valves in the flow control valve. FIG. 3a is a diagram showing the relationship between the triangular wave signal and the command signal, FIG. 3b is a diagram showing the relationship between the pulse signal and the solenoid drive time, and FIG. A diagram showing the relationship between the core and the solenoid opening/closing time, FIG. 4 is a running waveform diagram of the elevator, FIG. 5 is a block diagram showing the configuration of the correction method, FIG. 6 is a pattern diagram of the correction speed, and FIG. 7 is a , b are sectional views of main parts of a modified example of the pilot valve, FIG. 7a is a view corresponding to the pilot valves 80a and 80b in FIG. 2, and FIG.
This figure corresponds to the pilot valves 90a and 90b shown in the figure. B...Flow control valve, Ca...Hydraulic cylinder, D
... Car, 1 ... Temperature sensor, 2 ... Pressure sensor, 6 ... Correction/pulse device, 10 ... Valve body, 20 ... Main control valve for ascending, 30 ... Main control valve for descending, 40 ...Check valve, 80a, 80b...Pilot valve for ascending, 90a, 90b...Pilot valve for descending.

Claims (1)

[Claims] 1. In a hydraulic elevator that raises and lowers a car by supplying and discharging pressure oil to and from a hydraulic cylinder via a flow control valve, the flow control valve is provided within a valve body for raising and lowering. It has a structure that houses each main control valve, each pilot valve, and a check valve, and drives the pilot valve with a pulse train drive current having a pulse width proportional to the operation command signal corresponding to the operating conditions of the hydraulic elevator. A hydraulic elevator characterized in that the hydraulic elevator is configured to control each main control valve corresponding to each pilot valve. 2. The method according to claim 1, wherein at least one of the load and oil temperature of the hydraulic elevator is detected before operation, and the operation command signal is corrected in accordance with the detected value. Hydraulic elevator.