JPH08245107A - Hydraulic elevator - Google Patents

Abstract

PURPOSE: To easily confirm oil leakage of a hydraulic circuit without removing a valve at the time of maintenance and inspection by providing a pressure sensor and a timer between the side of a hydraulic jack of a flow rate control valve and a stop valve and computing existence of oil leakage by way of detecting pressure lowering speed from these measured values. CONSTITUTION: A hydraulic elevator absorbs oil in an oil tank 10 by a hydraulic pump 12 at the time of elevating a cage up and delivers the pressure oil to a hydraulic jack in an elevation track by a piping through a flow rate control valve 14, a silencer 18 and a stop valve 19. In this case, a pressure sensor 20 is installed on the silencer 18, the stop valve 9 is totally closed after changing a hydraulic circuit control device over to a maintenance and inspection mode at the time of maintenance and inspection, and oil is confined between the flow rate control valve 14 and the stop valve 19. Thereafter, pressure lowering quantity is found by measuring pressure of oil residing in a power unit and the piping, continuously existence of oil leakage of the flow rate control valve 14 is computed, and abnormality is indicated by an indicator.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to hydraulic elevators.

[0002]

2. Description of the Related Art Generally, there are two types of hydraulic elevators, a direct type in which a car is lifted up and down directly from below by a hydraulic jack, and an indirect type in which a car is lifted up and down using a hydraulic jack, a sheave, and a rope. Both of these types are equipped with a hydraulic power unit that drives a hydraulic jack. Here, as a conventional example, the configuration of a direct hydraulic elevator will be described with reference to FIG.

A direct hydraulic elevator is a hoistway 1 in a building.
A hydraulic jack 2 is erected at the bottom of the cylinder with the cylinder 3 embedded therein, a car 5 is placed directly on the plunger 4, and the hoistway 1 is moved up and down along a guide rail 6.

A hydraulic power unit 7 which is a drive source of the hydraulic jack 2 is generally installed in a machine room 8 adjacent to the hoistway 1.

As shown in the figure, the hydraulic power unit 7 includes an oil tank 10 installed on a frame 9, a hydraulic pump 12 for sucking and discharging the oil in the oil tank 10 through a filter 11, and a hydraulic pump 12 for this. Drive motor 13
And the flow control valve 1 provided on the discharge side of the hydraulic pump 12.
4 and a pipe 15 for connecting the same to the cylinder 3 of the hydraulic jack 2 and the like.

When the car 5 is raised, the hydraulic pump 12 works to suck the oil in the oil tank 10 through the filter 11 and control the flow rate of the generated pressure oil through the flow rate control valve 14 on the discharge side. While silencer 18
Through the pipe 15 to the cylinder 3 of the hydraulic jack 2 in the hoistway 1. As a result, the plunger 4 of the hydraulic jack 2 rises, the car 5 above it is pushed up, and rises to the destination floor.

To lower the car 5, the flow control valve 14 is switched so that the weight of the car 5 causes the oil in the cylinder 3 of the hydraulic jack 2 to flow from the pipe 15 to the flow control valve 14.
It is returned to the oil tank 10 while controlling the flow rate through. With this, the basket 4 together with the plunger 4 of the hydraulic jack 2
Goes down to the destination floor.

[0008]

However, in the hydraulic elevator having such a configuration, the check valve in the flow rate control valve, the check valve in the descending path, the electromagnetic control valve in the pilot path, etc. may be damaged due to a defective seal, foreign matter being caught, or the like. May cause oil leakage. In the case of such an oil leak, a large amount of oil does not leak in a short time and gradually leaks. Therefore, it is difficult for the elevator manager to notice this oil leak, and it is often not noticed during maintenance and inspection.

The above-mentioned oil leakage normally does not hinder the operation of the elevator at all, and when the car arrives at the floor, the releveling operation is performed when the car descends by a certain distance or more. However, if the oil leakage becomes larger than the standard, the releveling operation is repeated more than necessary, and the speed control during normal traveling is also adversely affected.

When these abnormalities occur, it is necessary to remove the valve from the power unit, bring it back to the factory or the like, and carry out a single item test in order to determine whether or not the above-mentioned abnormality is caused by oil leakage of the valve. , Was spending time and money.

The object of the present invention is to calculate whether or not there is an abnormality in pressure reduction with the passage of time with the stop valve fully closed, and to confirm the amount of oil leakage without removing the valve during maintenance and inspection. When the amount of leakage is above the standard, it is to be able to notify the replacement of the control valve due to an oil leakage abnormality.

[0012]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention detects a pressure of oil mounted on a silencer between a tank and a stop valve and transmits a signal, and a pressure based on a signal from the pressure sensor. The present invention is characterized in that a control device that calculates whether or not there is an abnormality in the amount of oil leakage from the amount of drop and that makes a predetermined value of the pressure drop rate variable, and an indicator that displays the abnormality are provided.

[0013]

With the above construction, the amount of oil leakage is confirmed without removing the flow control valve or the like at the time of maintenance and inspection of the hydraulic elevator, and when the oil leakage is significant, an instruction to replace the valve is displayed. Further, the predetermined value of the pressure drop rate of the hydraulic circuit control device can be changed.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described based on the embodiments shown in FIGS.

A silencer 18 is connected between the tank 10 and the stop valve 19.

A pressure sensor 20 is attached to the silencer 18 to detect the pressure of oil and generate a signal. During maintenance / inspection, after switching the hydraulic circuit control device 17 to the maintenance / inspection mode, the stop valve 19 is fully closed and the jack 2, cylinder 3, and plunger 4 are disconnected. Control valve 1 at this time
Since 4 is closed, the pressurized oil is trapped between the control valve 14 and the stop valve 19.

The pressure of this oil, that is, the oil remaining in the power unit 9 and the pipe 15 is measured, and the hydraulic circuit control device 17 determines whether or not there is an oil leak amount in the control valve 14 according to a flow chart according to the following equation ( The oil leak amount is calculated according to 1).

Oil leak calculation formula

[Formula 1] ΔP = (ΔV / V _c ) · K (1) where ΔP: Pressure drop rate (kgf / cm ² / min) ΔV: Oil leak volume (cm ³ / min) K: Volume Elastic coefficient (kgf / cm ² ) V _c : Confined volume (cm ³ ) If the standard of oil leakage is 1 (cm ³ / min) or less, temperature is 37.8 ° C., and bulk elastic coefficient is 1.825 × 10. ⁴ (kgf / c
m ² ), the confined volume is 32,000 (cm ³ ) (power unit A), and 50,000 (cm ³ ) (power unit B), the reference of the pressure drop amount is as shown in the characteristic curve of graph 1. Here, the trapped volume is the volume of oil remaining between the control valve 14 and the stop valve 19.

If the amount of oil leakage is above the reference level, that is, if the power unit A has a pressure drop amount exceeding the reference line A of the characteristic curve (Fig.), It means that the pressure drop is abnormal (abnormal oil leakage amount), and the control is performed. The oil leak abnormality of the valve 14 is displayed.

When the enclosed volume is larger (power unit B), the B reference line in the figure serves as a reference, and when it exceeds the reference line, the pressure drop becomes abnormal. In this way, the pressure drop rate changes depending on the trapped volume, and thus it is possible to change the predetermined value as the reference. In this way, it is possible to confirm the oil leak without removing the valve, and the labor and cost can be greatly reduced.

[0021]

According to the present invention, it is possible to easily check the presence or absence of oil leakage in the hydraulic circuit of the hydraulic elevator without removing the valve during maintenance and inspection, and it is possible to improve the reliability of the elevator.

[Brief description of drawings]

FIG. 1 is a configuration block diagram of a power unit of a hydraulic elevator according to the present invention,

FIG. 2 is a flowchart of the present invention,

FIG. 3 is a pressure drop characteristic curve diagram of power unit oil leakage,

FIG. 4 is a configuration diagram of a conventional hydraulic elevator.

[Explanation of symbols]

 1 ... Hoistway 10 ... Oil tank 2 ... Hydraulic jack 12 ... Hydraulic pump 3 ... Cylinder 13 ... Motor 4 ... Plunger 14 ... Flow control valve 5 ... Basket 15 ... Piping 7 ... Oil cooler 17 ... Hydraulic circuit controller 8 ... Machine room 18 ... Silencer 9 ... Hydraulic power unit 19 ... Stop valve 20 ... Pressure sensor

Claims (3)

[Claims] 1. A hydraulic elevator for raising and lowering a car by a hydraulic power unit including an oil tank, an oil pump, a flow control valve, a stop valve, a hydraulic circuit control device, and the like, and a hydraulic jack connected to the hydraulic power unit. An oil leak calculation control circuit device is provided between the hydraulic jack side and the stop valve, which has a pressure sensor for detecting oil pressure and a timer, and detects the pressure drop speed from these measured values to calculate the presence or absence of oil leak. Hydraulic elevator characterized by. 2. An indicator for displaying an oil leak when the pressure drop rate measured by the pressure sensor from the time when the stop valve is fully closed is equal to or more than a predetermined value is regarded as an oil leak. The hydraulic elevator according to claim 1. 3. The hydraulic pressure according to claim 1 or 2, wherein the predetermined value of the pressure drop rate is variably set according to the oil volume value in the pipe between the flow control valve and the stop valve. elevator.