JP4025089B2 - Hydraulic detector for lift device for vehicle - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention mainly relates to a pressure detector that is optimal for detecting when the hydraulic pressure of hydraulic oil drops below a predetermined value in a hydraulic cylinder of a lift device for a vehicle.
[0002]
[Prior art]
For inspection and maintenance of vehicles, particularly passenger cars, vehicle lift devices composed of a pair of vehicle receiving plates that move up and down in synchronization are used.
[0003]
The vehicle lift device is installed in a pit provided on the floor, and an interlocking hydraulic cylinder composed of a double-acting hydraulic cylinder and a single-acting hydraulic cylinder is used as a hydraulic cylinder for raising and lowering the vehicle receiving plate. The other single-acting hydraulic cylinder is operated by the secondary side hydraulic pressure of one double-acting hydraulic cylinder.
[0004]
However, if the hydraulic circuit of hydraulic fluid of these hydraulic cylinders cracks and causes oil leakage, the hydraulic pressure of the hydraulic oil does not increase. In particular, the vehicle that is moving up and down falls due to oil leakage in the secondary hydraulic circuit. It may lead to an accident. Therefore, when the oil pressure in the secondary side hydraulic circuit does not increase to a specified value, a vehicle lift device equipped with a low oil pressure alarm device that sounds an alarm device to inform the lift device operator of a decrease in oil pressure is known. Yes. (See Japanese Patent Application No. 2000-396591)
[0005]
Conventionally, as this type of pressure detector, a resistance wire type or piezoelectric pressure sensor or the like has been used, and the pressure of the hydraulic circuit is detected by an electric signal to operate the oil pressure drop alarm device of the hydraulic circuit. It was.
[0006]
[Problems to be solved by the invention]
However, in a device in which hydraulic circuits for the primary and secondary hydraulic fluids are buried in the ground, such as a vehicle lift device, an electric leakage is caused from a signal extraction unit from the electric pressure sensor. There is a problem that it is easy and maintenance of the pressure sensor is inconvenient.
[0007]
It is an object of the present invention to provide a pressure detector that solves these problems, is easy to maintain, and has no fear of leakage.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the present invention presses a pin formed so as to be slidable and movable in the cylindrical body toward the bottom surface of the cylindrical body using the spring force of the spring. A part of the lower end portion of the pin is formed so as to be in contact with the bottom surface portion of the cylindrical body, and the hydraulic oil is provided in a gap portion where the lower end portion of the pin and the bottom surface portion of the cylindrical body are not in contact with each other. When the hydraulic oil pressure rises above a predetermined pressure value, the pin rises over the spring force of the spring, and the head of the pin protrudes above the cylindrical body. An air vent hole having a spherical valve, a funnel-shaped valve seat and a set screw is provided at the center of the pin, and the air vent hole is connected to the introduction portion of the hydraulic oil. And
[0009]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the hydraulic pressure detector of the present invention will be described with reference to FIGS.
[0010]
In the present embodiment, the hydraulic detector of the present invention is applied to a vehicle lift device used for inspection and maintenance of a vehicle such as a passenger car in an automobile maintenance factory.
[0011]
That is, FIG. 1 is a side view of the vehicle lift device 1 of the present embodiment, and FIG. 2 is a plan view thereof.
[0012]
The vehicle lift device 1 has two sets of double-acting hydraulic cylinders 2a and 2b and two sets of single-acting hydraulic cylinders 3a and 3b in a pit P provided on the floor surface. On the pit P, there are a pair of vehicle receiving plates 4a, 4b. The two sets of double acting hydraulic cylinders 2a, 2b support one vehicle receiving plate 4a, and the two sets of single acting hydraulic cylinders 3a. 3b supports the other vehicle receiving plate 4b.
[0013]
A pair of swing arms 5a, 5b or 5c, 5d are pivotally mounted on the vehicle receiving plates 4a, 4b so as to be extendable and turnable.
[0014]
Receiving metal fittings 5e for supporting the vehicle body project upward from the respective tip portions of the swing arms 5a to 5d.
[0015]
Reference numerals 2c and 2d denote cylinder heads of the double-acting hydraulic cylinders 2a and 2b, respectively.
[0016]
6a is a connection port to the primary side hydraulic pipeline of each of the double acting hydraulic cylinders 2a, 2b, and 6b is a connection port to the secondary side hydraulic pipeline of each of the double acting hydraulic cylinders 2a, 2b. is there.
[0017]
6c is a secondary side hydraulic line, and the secondary side hydraulic line 6c connects the connection port 6b of the double acting hydraulic cylinder 2a or 2b and the connection port 6d of the single acting hydraulic cylinder 3a or 3b, respectively. Connected to each other.
[0018]
FIG. 3 is a detailed view of the double-acting hydraulic cylinder 2a or 2b, partly in cross section.
[0019]
That is, 2e is a cylinder, 2f is a piston that slides up and down in the cylinder 2e, 2g is a ram that stands on the piston 2f, and the ram 2g passes through the cylinder 2e together with the piston 2f. The portion through which the ram 2g passes the cylinder head 2c or 2d is formed to slide oil-tightly.
[0020]
Below the piston 2f is a primary side hydraulic chamber 6e connected to a primary hydraulic line via a connection port 6a, and above the piston 2f is a secondary side hydraulic pressure via a connection port 6b. There is a secondary hydraulic chamber 6f that communicates with the pipeline 6c.
[0021]
The cylinder heads 2c and 2d are each provided with a hydraulic pressure detector 7 of the present invention, and the hydraulic pressure of the secondary hydraulic chamber 6f is introduced below each hydraulic pressure detector 7.
[0022]
The details of the hydraulic pressure detector 7 and its mounting portion are shown in FIG.
[0023]
That is, the oil pressure detector 7 is inserted and locked in a vertical hole 2h provided in each upper part of the cylinder heads 2c and 2d. The oil pressure detector 7 includes a cylindrical sleeve 7a and an inner sleeve 7a. And a spring 7c that presses the pin 7b toward the bottom surface of the vertical hole 2h with a predetermined force.
[0024]
The pin 7b has an air vent hole 7d passing through the center thereof, and the upper half of the air vent hole 7d is formed as a large-diameter screw groove 7e, and between the screw groove 7e and the lower half of the air vent hole 7d. A funnel-shaped valve seat 7f is provided between the cap screws 7g, and a holding screw 7g screwed into the screw groove 7e presses the spherical valve 7h against the valve seat 7f to stop the hydraulic oil from flowing out. ing.
[0025]
Further, the pin 7b has a contact portion 7i at a part of the lower end portion and is seated in contact with the bottom surface portion of the vertical hole 2h, and between the other portion of the lower end portion and the bottom surface portion of the vertical hole 2h. There is a gap 7j between them.
[0026]
Furthermore, the lower end portion of the pin 7b has a columnar protruding portion 7k protruding downward, and the protruding portion 7k is loosely inserted through the guide hole 6h provided in the bottom surface portion of the vertical hole 2h. ing.
[0027]
Since the center of the projecting portion 7k is in an eccentric position with respect to the axial center of the pin 7b, the pin 7b does not rotate together even if the holding screw 7g is tightened or loosened.
[0028]
The protrusion 7k is inserted into the guide hole 6h sufficiently deeper than the stroke of the pin 7b, and even if the pin 7b rises to the top dead center, the protrusion 7k is removed from the guide hole 6h. Never get out.
[0029]
The gap 7j communicates with the air vent hole 7d and communicates with the secondary hydraulic chamber 6f through the guide hole 6h and the communication path 6g.
[0030]
In addition, 7m is an oil seal.
[0031]
Next, the operation of the vehicle lift device 1 of the present embodiment will be described.
[0032]
A vehicle to be lifted up is stopped on the pit P, and a pair of vehicle receiving plates 4a is formed so that the receiving metal 5e at each end of each of the swing arms 5a to 5d abuts on a supporting point of the vehicle. 4b is raised.
[0033]
That is, when the primary side hydraulic pressure is supplied to the primary side connection ports 6a of the two sets of double acting hydraulic cylinders 2a and 2b that support the vehicle receiving plate 4a, the primary side hydraulic chamber 6e shown in FIG. The hydraulic oil on the next side is fed, and the piston 2f and the ram 2g are raised to raise the vehicle receiving plate 4a.
[0034]
At the same time, the secondary hydraulic fluid is pushed out from the secondary hydraulic chamber 6f above the piston 2f, and the connection ports of the single-acting hydraulic cylinders 2c and 2d from the connection port 6b through the secondary hydraulic line 6c. 6d, the pistons and rams (not shown) of the single-acting hydraulic cylinders 2c and 2d are raised, and the other vehicle receiving plate 4b is raised. The oil pressure of the secondary hydraulic chamber 6f generated at this time acts on the gap 7j of the oil pressure detector 7, and the oil pressure increases the pin 7b by overcoming a predetermined pressing force by the elastic force of the spring 7c. The head of the pin 7b protrudes above the sleeve 7a.
[0035]
That is, when the pin 7b rises slightly due to the oil pressure applied to the gap 7j, the oil pressure also acts on the contact portion 7i, so that the pin 7b rises to the upper stop position all at once.
[0036]
Above the pin 7b, there is a normally closed micro switch, which operates so that the low oil pressure alarm is not activated while the head of the pin 7b is pressing the micro switch.
[0037]
Should an oil leak occur due to a crack or the like in one of the two secondary side hydraulic pipes 6c, the hydraulic oil pressure in the single-acting hydraulic cylinder on the failed side will drop. It is impossible to move up and down in synchronization with the other single-acting hydraulic cylinder. This is dangerous because it causes the vehicle receiving plate 4b to be inclined. When the secondary hydraulic pressure becomes lower than the set value, the pin 7b is lowered by the elastic force of the spring 7c, and the microswitch by its head is used. It is possible to release the press and immediately actuate a hydraulic pressure drop alarm to notify the operator of the vehicle lift device that a failure has occurred and prevent an accident.
[0038]
The oil pressure detector 7 has an air vent part of the secondary side hydraulic circuit. This is because the oil pressure detector 7 is located above the cylinder heads 2c and 2d of the double-acting hydraulic cylinders 2a and 2b so that people can easily approach and have excellent accessibility, and at the top of the secondary hydraulic circuit. This makes use of the advantage that air can easily escape.
[0039]
In the air venting method, the holding screw 7g is loosened to provide a gap between the valve 7h and the valve seat 7f so that the air in the air vent hole 7d is released to the outside through the screw groove 7e.
[0040]
【The invention's effect】
As described above, according to the present invention, since a mechanically operated hydraulic pressure detector can be provided, there is no fear of electric leakage, and if the hydraulic pressure detector is applied to a hydraulic pressure drop alarm device of a vehicle lift device, Since the access to the detector is good and the air of the hydraulic circuit can be easily vented, the maintenance of the lift device is facilitated and the safety is improved.
[Brief description of the drawings]
FIG. 1 is a side view of a lift device for a vehicle according to an embodiment of the present invention.
FIG. 2 is a plan view of the lift device.
FIG. 3 is a detailed view of a partially double-acting hydraulic cylinder of the lift device.
FIG. 4 is a detailed view of a partial hydraulic pressure detector and its mounting portion of the lift device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Vehicle lift apparatus 2a, 2b Double acting hydraulic cylinder 2c, 2d Cylinder head 3a, 3b Single acting hydraulic cylinder 7 Oil pressure detector 7a Cylindrical body (sleeve)
7b Pin 7c Spring 7d Air vent hole 7f Funnel-shaped valve seat 7g Holding screw 7h Spherical valve 7i Contact part 7j Gap part 7k Protrusion part

Claims (2)

A pin formed so as to be slidable in the cylindrical body is pressed toward the bottom surface of the cylindrical body using the elastic force of a spring, and a part of the lower end of the pin is part of the cylindrical shape. The hydraulic oil is introduced into a gap portion where the lower end portion of the pin and the bottom surface portion of the cylindrical body are not in contact with each other, and the pressure of the hydraulic oil is reduced. said pin when increased to above a predetermined pressure value is increased by overcoming the resilient force of the spring is formed so as to protrude the pin head above the cylindrical body, the central portion of the pin An oil pressure detector for a vehicle lift device, characterized in that an air vent hole having a spherical valve, a funnel-shaped valve seat and a set screw is provided, and the air vent hole is connected to the introduction portion of the hydraulic oil. A protrusion projecting downward is formed at the lower end of the pin at a position eccentric with respect to the axial center of the pin, and the protrusion plays a guide hole provided in the bottom surface of the cylindrical body. The hydraulic pressure detector for a vehicle lift device according to claim 1, wherein the hydraulic pressure detector is fitted and inserted .

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