JPH06305675A - Vacuum sucking device - Google Patents

Abstract

PURPOSE:To provide a vacuum sucking device which is less in air consumption and of which sucking force can be raised in a short time after vacuum rupture. CONSTITUTION:A venturi 10 is connected to an air source 6 through a venturi valve 8. A vacuum pad 12 is connected to the negative pressure part of the venturi 10 through a check valve 14. The air source 6 is connected to the vacuum pad 12 through a vacuum rupture valve 18a and a vacuum rupture path 21. Also it is detected by a pressure sensor 16 whether the vacuum pressure of the vacuum pad 12 is larger or smaller than a specified limit and, only when it is below the specified limit, the venturi valve 8 is operated to open. Then a pressure sensitive stop valve 24 operated to open by a pressure from the air source 6 is located in the vacuum rupture path 21 between the vacuum pad 12 and the vacuum rupture valve 18a.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a vacuum adsorption device.

[0002]

2. Description of the Related Art A vacuum adsorption device is used for adsorbing and holding a thin steel plate or the like for conveyance. This vacuum adsorption device 2 has a plurality of units (only two units are shown in the illustrated example) at the tip of the robot arm 4 as shown in FIG. 5, for example.
Used by mounting. These vacuum adsorption devices 2
It is a dedicated product for each type of work to be adsorbed, and the vacuum adsorption device 2 can be replaced together when changing the stage of the work.

FIG. 6 shows a piping structure of the vacuum adsorption device 2 shown in FIG. 5 and 6, 6 is an air source, and 8
Is an electromagnetic venturi valve, 10 is a venturi, 11 is a horizontal frame, 12 is a plurality of vacuum pads supported by the horizontal frame 11, 16 is a pressure sensor for detecting a negative pressure of the vacuum pad 12, and 18 is a vacuum pad 1.
An electromagnetic vacuum breaking valve for forcibly introducing a positive pressure (vacuum breaking pressure) into 2 and a vacuum breaking passage 21.

In the vacuum adsorption device 2, when the air from the air source 6 passes through the venturi 10, a negative pressure is generated in the throat of the venturi 10. This negative pressure is introduced into the vacuum pad 12 and sucks and supports the plate-like work 20 such as a thin steel plate.

When the work 20 is released, the venturi valve 8 is closed to stop the generation of negative pressure, and the vacuum break valve 18 is opened to forcibly introduce the positive pressure from the air source 6 to the vacuum pad 12. The suction force of the vacuum pad 12 is instantly set to zero.

[0006] The vacuum adsorption device 2 is the work 2
Since air from the air source 6 continues to flow to the venturi 10 while 0 is adsorbed, energy is wasted and exhaust sound from the venturi 10 becomes noise. Also,
Since the vacuum break valve 18 is generally distant from the vacuum pad 12, even if the venturi valve 8 is opened to adsorb a new work 20 after the work 20 is vacuum broken to release the work 20, the vacuum break passage 21 is placed in the vacuum break passage 21. It takes time to exhaust the remaining air, and the suction force of the vacuum pad 12 does not rise quickly, which is an obstacle in increasing the work transfer cycle speed.

Therefore, as shown in FIG. 7, the venturi 10 is used.
The check valve 14 is disposed between the vacuum pad 12 and the vacuum pad 12, and the venturi valve 8 and the venturi 1 are provided.
0, the check valve 14, the vacuum breaking valve 18, etc. are integrated as a unit 19 to reduce the air consumption and shorten the vacuum breaking passage 21. In the figure, 86 is an air relief valve, and 88 is a pressure switch.

[0008]

The improved vacuum adsorption device 2a of FIG. 7 has a small number of piping points because it is unitized, but three valves 8, 18 are provided for each unit 19.
Since 86 is incorporated, increasing the number of vacuum pads 12 inevitably increases the number of units 19 and thus the total number of valves, which complicates the routing of control lines for these valves. Further, since the unit 19 is a valve built-in type and is expensive, it is costly to hold the configuration from the unit 19 to the vacuum pad 12 as a dedicated product for each type of the work 20.

Further, as a problem common to the apparatuses of FIGS. 6 and 7, there is a problem of the sealing property of the vacuum break valve 18. That is, the vacuum breaking valve 18 constantly seals the vacuum pressure while the work piece 20 is adsorbed by the vacuum pad 12, and therefore a highly accurate vacuum sealing performance is required to keep the vacuum in particular.

To prevent the vacuum pressure from acting on the vacuum breaking valve 18, a check valve may be provided in the vacuum breaking passage 21. However, in that case, it becomes impossible to send the vacuum breaking pressure to the vacuum pad 12.

An object of the present invention is that the venturi valve, the vacuum break valve and the venturi are not integrated into a unit, and yet the time until re-adsorption after vacuum break is as short as before, and the vacuum break valve is It is an object of the present invention to provide a vacuum adsorption device capable of significantly improving the durability of the valve by preventing the vacuum pressure from acting even while adsorbing and holding a workpiece, and at the same time introducing the vacuum breaking pressure into the vacuum pad.

[0012]

A feature of the present invention is that the venturi valve and the vacuum break valve are independent of each other, a check valve is provided between the venturi and the vacuum pad, and the vacuum pad and the vacuum break valve are connected to each other. The pressure-sensitive open / close valve that is opened by the pressure from the air source is installed in the vacuum break passage between them.

[0013]

[Function] After the work is adsorbed and supported by the vacuum pad, the venturi valve is closed. Since the vacuum pressure of the vacuum pad is held by the check valve, the work remains adsorbed and supported by the vacuum pad even when the venturi valve is closed.

Next, when the vacuum breaking valve is opened, the positive pressure from the air source acts on the pressure-sensitive opening / closing valve to open the same. As a result, the positive pressure is introduced into the vacuum pad, the suction force thereof instantly becomes zero, and the workpiece suction-supported by the vacuum pad separates from the vacuum pad.

The pressure sensitive opening / closing valve is located closer to the vacuum pad side than the vacuum breaking valve, and when the vacuum breaking valve is closed after the vacuum breaking and the venturi valve is opened to adsorb and support a new work, the pressure sensitive opening / closing valve is pressed. The on-off valve is already closed, and the air trapped in the vacuum break passage between the valve and the vacuum break valve is not sucked out to the venturi side. Therefore, the suction force of the vacuum pad rises quickly. During the suction and support of the work, the vacuum pressure is shut off by the pressure sensitive opening / closing valve and does not affect the vacuum breaking valve at all.

[0016]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows the same view as FIG. 5, and the same parts are denoted by the same reference numerals. This vacuum adsorption device 2b is different from that shown in FIG. 5 in that, as shown in FIG. 2, a conventional check valve 14 and a new pressure-sensitive open / close valve 24 are housed in an adsorption holding unit 22, and a vacuum break valve 18a is normally installed. That is, the atmospheric pressure is introduced into the pressure sensitive on-off valve 24.

More specifically, as shown in FIG. 2, the pressure sensitive on-off valve 24 is a two-position switching type two-port valve, and when a pressure higher than a predetermined pressure acts on the vacuum breaking passage 21, the valve automatically opens. The ports on both sides communicate with each other.

A specific example of the suction holding unit 22 is shown in FIGS. In the figure, 26 is an integral housing, 28 is a cover plate, and the cover plate 28 is fixed to the upper surface of the housing 26 by a plurality of bolts 30. Of the two holes 32, 34 formed in the cover plate 28, one hole 32 is connected to the throat (negative pressure part) of the venturi 10 by the passage 36, and the other hole 34 is vacuum-break by the vacuum break passage 21. It is connected to the valve 18a. The hole 40 formed in the lower surface of the housing 26 is connected to the vacuum pad 12 by a passage 42. Further, the hole 44 formed in the side surface of the housing 26 is provided with the passage 46 so that the pressure sensor 1
Connected to 6.

In the housing 26, a check valve 14 is provided in a vertical hole 48 which vertically connects the hole 32 and the hole 40.
Is provided. The intermediate portion of the vertical hole 48 also communicates with the pressure sensor 16 via the hole 44. The check valve 14 is a hollow cylindrical valve body 5 having an upper end closed and a lower end opened.
0 and the valve seat 5 is integrally fitted around the upper end of the valve body 50.
It is composed of a rubber ring member 52 seated on the No. 4 and a spring 56 for urging the valve body 50 downward. The valve body 50
A communication hole 58 that communicates the inside and the outside of the valve body 50 is formed in the peripheral wall of the.

A rubber diaphragm 62 is disposed on the side of the vertical hole 48. This diaphragm 62
Are constantly urged upward by a compression spring 66 arranged between the lower support plate 64 and the lower support plate 64. The periphery of the upper surface of the diaphragm 62 is communicated with the vacuum break valve 18 a through the passage 63, the hole 34, and the vacuum break passage 21. The periphery of the central thick portion of the diaphragm 62 is always seated on the valve seat 68, and the upper surface of the central thick portion communicates with the inside and outside of the peripheral wall portion of the valve body 50 of the check valve 14 via the passage 70.

Next, the operation of the vacuum adsorption device 2b will be described. In the rest state of the device 2b, as shown in FIG. 2, the venturi valve 8 and the pressure sensitive on-off valve 24 are closed,
The vacuum break valve 18a closes the air source 6 side, and opens the pressure sensitive opening / closing valve 24 side to the atmosphere.

When the venturi valve 8 is opened by a control circuit (not shown) in order to suck and support the work 20 with the vacuum pad 12, air is flown into the venturi 10 and a negative pressure is generated in the throat. Due to this negative pressure, the valve body 50 of the check valve 14 rises against the spring 56 in FIG. 3, and a gap is formed between the ring member 52 and the valve seat 54. Negative pressure is introduced into the vacuum pad 12 through this gap to adsorb and support the work 20. At this time, a negative pressure acts on the upper surface of the thick center portion of the diaphragm 62, and the diaphragm 62 is pushed upward by the force of the compression spring 66, so that the valve seat 68 of the diaphragm 62 is closed.

The pressure sensor 16 detects whether or not the vacuum pressure of the vacuum pad 12 is a predetermined value or more, and if it is the predetermined value or more, the venturi valve 8 is controlled by a control circuit (not shown).
To block. Even if the venturi valve 8 is closed, the vacuum pressure of the vacuum pad 12 is maintained by the check valve 14, so that the work 20 remains adsorbed and supported by the vacuum pad 12. Further, when the work 20 is adsorbed and supported for a long time, the vacuum pressure of the vacuum pad 12 gradually decreases due to air leakage from the vacuum pad 12, etc., but when the vacuum pressure becomes a predetermined value or less, the venturi valve 8 is opened and the vacuum pressure is reduced. Negative pressure is supplied to the pad 12.

Next, the work 20 is attached to the vacuum pad 12
When releasing from, the venturi valve 8 is closed and the vacuum break valve 18a is opened. As a result, the supply of vacuum pressure to the vacuum pad 12 is stopped, and the positive pressure from the air source 6 acts on the pressure-sensitive open / close valve 24 through the vacuum break valve 18a, causing the diaphragm 62 of the valve 24 to act as a compression spring 66. Then, the positive pressure is forcedly introduced into the vacuum pad 12 through the passage 70, the communication hole 58, the vertical hole 48 and the passage 42. Therefore, the negative pressure in the vacuum pad 12 is quickly eliminated, the suction force is instantly reduced to zero, and the work 20 separates from the vacuum pad 12.

[0025]

As described above, according to the present invention, the venturi valve and the vacuum break valve are separately configured, the check valve is provided between the venturi and the vacuum pad, and the vacuum break valve and the vacuum pad are separated from each other. Since a pressure sensitive on-off valve is installed between them, one venturi valve and one vacuum break valve can configure the air supply system, so even if each valve is a large flow type, the impact on cost and weight is minimal. Moreover, since a large number of venturi and vacuum pads can be connected to one venturi valve, the cost of the adsorption device as a whole can be reduced. In addition, when negative pressure is applied to the vacuum pad after breaking the vacuum, the air on the upstream side of the pressure-sensitive on-off valve is not sucked out to the venturi side, so the suction force of the vacuum pad can rise faster, which makes it easier The cycle time can be shortened, and the vacuum break valve does not act on negative pressure, so its durability can be improved, and the vacuum holding function of the vacuum pad by the check valve can reduce the air source consumption, thus saving energy and noise. It also has a reduction effect. Further, even if the vacuum breaking valve is arranged far away from the vacuum pad, there is no problem in the rise of the suction force of the vacuum pad, so that the degree of freedom in valve arrangement is improved. Also, if the check valve and the pressure-sensitive on-off valve are integrated as a suction holding unit, the number of piping points will be reduced, and assembly work will be saved.

[Brief description of drawings]

FIG. 1 is a schematic view of a vacuum adsorption device according to the present invention.

FIG. 2 is a piping diagram of the vacuum adsorption device.

FIG. 3 is a cross-sectional view of a suction holding unit.

FIG. 4 is a plan view of a suction holding unit.

FIG. 5 is a schematic view of a conventional vacuum adsorption device.

FIG. 6 is a piping diagram of the vacuum adsorption device.

FIG. 7 is a piping diagram of a conventional vacuum adsorption device in which each valve, venturi, and the like are unitized. 18 Vacuum Breaking Valve 20 Work 21 Vacuum Breaking Passage 22 Adsorption Holding Unit 24 Pressure Sensitive Open / Close Valve 26 Housing 62 Diaphragm

Claims (2)

[Claims] 1. A vacuum break of a venturi connected to an air source via a venturi valve, a vacuum pad connected to a negative pressure portion of the venturi via a check valve, and the air source and the vacuum pad. A vacuum break passage communicating through a valve, and connected to the vacuum pad to detect whether the vacuum pressure of the vacuum pad is above or below a predetermined value, and to open the venturi valve only when the vacuum pressure is below a predetermined value. In a vacuum adsorption device equipped with a sensor, a vacuum sensitive passage which is opened by a pressure from the air source is arranged in a vacuum breaking passage between the vacuum pad and the vacuum breaking valve. Adsorption device. 2. A vacuum adsorption device in which the check valve and the pressure-sensitive on-off valve are housed in an integral housing.