JP2585899B2 - Correction method of tuning deviation in cylinder mechanism of vehicle maintenance lift - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[Industrial application] A plurality of double-acting cylinder mechanisms for raising and lowering a vehicle support are connected in series, and each cylinder mechanism is moved upward in synchronism, and the piston is forcibly lowered by the reverse flow of hydraulic oil. The present invention relates to a method for correcting a tuning deviation in a cylinder mechanism of a vehicle maintenance lift to be operated.

[0002]

2. Description of the Related Art As a method of correcting a tuning deviation in a cylinder mechanism of a vehicle maintenance lift, for example, as shown in FIG. 3, a communication path 15 for connecting a piston 6 to both cylinder chambers 1a and 1b is provided. 15, a check valve 17 having a check function for the lower cylinder chamber 1b, for example.
And a push-up pin 20 protrudes from the bottom surface of the lower cylinder chamber 1b to lower the piston 6 by the reverse flow of the hydraulic oil. When the piston 6 approaches the lower limit position, the ball 1
7a is raised by the push-up pin 20 and the check valve 1
7, the hydraulic oil is allowed to pass from the upper cylinder chamber 1a to the lower cylinder chamber 1b, from which the piston 6 naturally descends to the lower limit, and the height of the piston 6 is adjusted to the same level at the lower limit position. Attempts have been made to allow hydraulic oil to pass through the cylinder without resistance.

[0003]

The idea of correcting the piston at the lower limit position in the event of a synchronization deviation by forcibly lowering the hydraulic pressure by operating the hydraulic pressure in the reverse direction is, in fact, valid even if it is theoretically valid. Both pistons may not completely descend to the lower limit due to sliding resistance, oil viscosity resistance, etc.As a result, there is no correction, There was a risk of causing this.

[0004]

SUMMARY OF THE INVENTION According to the present invention, a piston is depressed until a lower limit is reached by intentionally providing a restrictor in a communication passage and maintaining a depressing force of the piston even after a check valve is opened. Level is surely adjusted.

[0005]

Each time the lift-down operation is performed, the piston position is corrected so as to coincide with the lower limit at the same time as confirmation, so that there is no trouble and the best tuning state is always maintained, so reliability is high. .

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for correcting a tuning deviation in a cylinder mechanism according to the present invention will be described with reference to the drawings, with reference to an example in which the method is applied to an embedded lift. Reference numerals 1 and 2 denote a pair of double-acting cylinder mechanisms (hereinafter, simply referred to as cylinder mechanisms) housed in the pit 4 in a vertical posture with the protruding directions of the piston rods 3 and 3 facing upward, respectively. Drive-on plates 5, 5, which are vehicle supports, are provided at the upper end of 3,
Are fixed, and the two cylinder mechanisms 1 and 2 are connected in series by a reversible oil passage described later. Since the cylinder mechanisms 1 and 2 are the same model and are confusing, the following description will distinguish 1 as a driving cylinder mechanism and 2 as a driven cylinder mechanism.

The interior of each of the cylinder mechanisms 1 and 2 includes a piston 6
, The upper cylinder chamber 1a of the driving cylinder mechanism 1 and the lower cylinder chamber 2b of the driven cylinder mechanism 2 are connected by a communication oil passage 7, and the lower cylinder chamber 1b of the driving cylinder mechanism 1 is connected. The upper cylinder chamber 2a of the driven cylinder mechanism 2 is connected to a switching valve 10 via a feed oil passage 8 and a return oil passage 9, respectively. Further, the switching valve 10 is provided with a pump 11 and a pressure feed path 13 for sending out the working oil in an oil tank 12 and a return path 14 for sending the working oil back to the oil tank 12. The operation of the switching valve 10 causes the pressure feed path 13 and the return path 14 to be directly connected, and then the pressure feed path 13 and the feed oil path 8 and the return oil path 9 and the return path 14 to connect the hydraulic oil to the drive side. An ascending side for feeding hydraulic fluid in the upper cylinder chamber 2a of the driven cylinder mechanism 2 to the lower cylinder chamber 1b of the driven cylinder mechanism 2 and returning the hydraulic oil to the oil tank 12; And the feed oil passage 8 and the return passage 14 are connected to each other to feed hydraulic oil into the upper cylinder chamber 2a of the driven cylinder mechanism 2 and forcibly lift down the drive cylinder mechanism 2.
A reversible configuration is adopted in which the hydraulic oil in the lower cylinder chamber 1b is switched to the descending side, which circulates in the reverse direction to return to the oil tank 12 (FIG. 2).

Next, the cylinder mechanisms 1 and 2 will be described. Since both cylinder mechanisms have the same structure as described above, only the drive side cylinder mechanism 1 will be described. When sticking,
A communication path 15 is provided which is constituted by a horizontal hole 15a penetrating in a direction orthogonal to the axial direction of the rod and a vertical hole 15b penetrating the center of the piston portion. In the vertical hole 15b, upper and lower cylinder chambers 1a, 1b are provided. Check valves 16 and 17 each having a check function are provided for the
A bush 18 for press-fitting the aperture by narrowing the hole diameter is inserted into a.

The lower end of the piston 6 has a through hole 1 at the center.
A pin holder 19 having a through hole 9a is provided.
The push-up pin 20 is suspended from the push-up pin 20 with the ring body 20a fitted to the intermediate portion thereof being locked and the lower end protruding downward. As a result, when the piston 6 is raised, the check valves 16 and 17 operate to prevent the flow of hydraulic oil between the two cylinder chambers 1a and 1b (a in FIG. 1), and when the piston 6 is lowered, the pin holder 19 is moved.
Immediately before contact with the bottom surface of the cylinder chamber 1b, the push-up pin 20 comes into contact with the bottom surface of the cylinder chamber 1b and is pushed up. As a result, the ball 17a of the check valve 17 is pushed up and the check valve 17 is opened. The flow of the hydraulic oil is allowed from the upper cylinder chamber 1a toward the lower cylinder chamber 1b (FIG. 1B).

In the thus-built embedded lift, when the switching valve is switched to the rising side at the time of lift-up, the hydraulic oil in the oil tank is pumped into the lower cylinder chamber 1b of the drive-side cylinder mechanism 1 by a pump.
The piston 6 of the drive-side cylinder mechanism 1 is pushed up, whereby hydraulic oil in the upper cylinder chamber 1a of the drive-side cylinder mechanism 1 is sent out to the lower cylinder chamber 2b of the driven-side cylinder 2 via the communication oil passage 7, and The piston 6 of the cylinder mechanism 1 is pushed up in synchronization with the piston 6 of the drive-side cylinder mechanism 1, and the operating oil in the upper cylinder chamber 2 a of the driven-side cylinder mechanism 2 is returned to the oil tank, and By setting the cross-sectional areas of the cylinder chamber 1a and the lower cylinder chamber 2b of the driven cylinder mechanism 2 to be equal, the two pistons 6, 6 are raised synchronously.

When the switching valve is switched to the descending side, the operation opposite to the lift-up operation is performed, the pistons 6, 6 are forcibly pushed down, and when the piston 6 reaches the lower limit, the check valve 17 is opened. As a result, the hydraulic oil passes through both cylinders. And a throttle mechanism is configured by press-fitting the bush into the communication path,
In the hydraulic oil passing state, a load is applied to the communication path, and a pressing force acts on the piston. Therefore, even if the piston tends to stagnate just before reaching the lower limit due to sliding resistance or viscous resistance, it is forcibly pushed down to the lower limit.

The throttle mechanism of this embodiment is constructed by press-fitting a bush into the communication passage. However, the degree of throttle can be adjusted by a variable valve, and the degree of throttle can be adjusted from the driven side to the driven side. It is possible to increase the value so that it is corrected in order from the drive side, or when the piston reaches the lower limit, the throttle can be opened to allow the hydraulic oil to pass through without resistance. The throttle may be provided at any position in the communication path by any means. Further, in the embodiment, the embedded lift is described. However, the present invention can be applied to a floor type such as a two-post type, a four-post type, or the like, and the structure of the check valve may be appropriately changed. After the communication passage is opened, a pressure difference is generated by the throttling action, and the piston is forcibly pushed down. The idea of the present invention is that, in a lift without a forced lowering function, the piston is leveled at the upper limit of the cylinder. It is added that the technology can be applied to

[0013]

According to the present invention, when lift-down is performed, it is confirmed that synchronization has been achieved, and at the same time, if there is a synchronization deviation, it is automatically and reliably corrected. You can use it with confidence.

[Brief description of the drawings]

FIGS. 1A and 1B are explanatory views showing a cylinder mechanism of an embedded lift in which a method for correcting a tuning shift in a cylinder mechanism according to the present invention is implemented.

FIG. 2 is a hydraulic circuit diagram of an embedded lift in which a method of correcting a tuning shift in a cylinder mechanism according to the present invention is implemented.

FIG. 3 is an explanatory diagram of a conventional example.

[Explanation of symbols]

1. Drive-side cylinder mechanism, 2. Drive-side cylinder mechanism, 1a, 2a .. upper cylinder chamber, 1b, 2b .. lower cylinder chamber, 3. piston rod, 4. pit, 5.
・ Drive-on plate, 6 ・ ・ Piston, 7 ・ ・ Connection oil path, 8 ・ ・ Feed oil path, 9 ・ ・ Return oil path, 10 ・ ・ Switch valve, 11 ・ ・ Pump, 12 ・ ・ Oil tank,
13 ··· Pressure path, 14 ··· Return path, 15 ·· Communication path, 1
5a horizontal hole, 15b vertical hole, 16, 17 check valve, 17a ball, 18 bush, 19
..Pin holder, 20..Push-up pin.

Claims (1)

(57) [Claims] 1. A plurality of double-acting cylinder mechanisms for raising and lowering a vehicle support are connected in series, and each cylinder mechanism is synchronously raised by supplying hydraulic oil, and a piston is forcibly generated by a reverse flow of hydraulic oil. In a vehicle maintenance lift which is operated to descend downward, a communication path for communicating both cylinder chambers with a piston is provided, and a check valve for opening the piston at a lower limit position is provided in the communication path, and the communication path is intentionally connected to the communication path. Even if the check valve is opened by applying a restrictive force, a pressure difference is generated between the two cylinder chambers, and the piston is reliably pushed down to the lower limit position by the continuous pushing down force. Method.