JPH0699386A - Vacuum sucker device - Google Patents

Abstract

PURPOSE:To surely suck a sucked object with no necessity for accurate control of on-timing of a sucking source by providing a bypass means for connecting a sucking chamber to a sucking passage by a flow sufficiently smaller than the sucking passage in the case of closing the sucking chamber and the sucking passage by a movable valve. CONSTITUTION:When sucker pads P8 of a vacuum sucker device are brought into contact with a hole or the like of a printed board 7, a movable valve 25 is lifted by sucking force to close a sucking passage 20, and the other vacuum sucker device total unit connected by the sucking passage 20 holds a vacuum condition, to suck the printed board 7 conveyed. Here by roughing a work surface of a contact surface part 65 to serve as a bypass means, a fine amount of air is fed to the sucking passage 20. A pressure of air in the sucking passage 20 is thus equalized to that of a sucking chamber 2, and the movable valve 25 is moved by its own weight to suck the printed board 7. In this way, the valve in a spot of imperfect suction is automatically controlled, and suction can be surely performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum suction device, and more particularly to a structure for automatically opening and closing a valve of a suction pad which is not completely sucked by an object to be sucked.

[0002]

2. Description of the Related Art Generally, in the step of mounting electronic parts and the like on a printed board (mounting step), each part or printed board is transported to a necessary step. A belt conveyor or a vacuum suction device is used for this transportation.

In order to carry using this vacuum suction device, usually one suction source is provided with a plurality of suction pads to suck the printed board. The suction is performed by applying the suction pad to the printed board and sealing the suction pad.

However, the printed board may have holes or dents. Even if the suction pad is applied to such a place, the opening of the suction pad is not completely closed. Therefore, even if suction is performed, that portion does not become a vacuum, and the suction pressure at the suction source becomes low even if suction is performed by another suction pad. In other words, the suction pressure is low as a whole and the print board cannot be sucked and cannot be conveyed. Therefore, it was an obstacle to automation of the production line.

Therefore, conventionally, a structure has been proposed in which only the suction operation of the vacuum suction device in which the suction of the suction pad is not sealed is stopped. This structure is shown in FIG.

As shown in FIG. 4, the transfer device 80 is provided with seven vacuum suction devices S1 to S7 for suctioning the printed board 7. Suction pads P1 to P7 are provided on the vacuum suction devices S1 to S7, respectively. An air filter 26 is provided in each of the vacuum suction devices S1 to S7, and the movable valve 25 is located above the air filter 26. Printed board 7
In the case of adsorbing, the transport device 80 descends and contacts the printed board 7. The print board 7 has dents D1 to D3.

First, the operation of the vacuum suction device, for example, S1 which is not in contact with the depressions D1 to D3 will be described with reference to FIG. 5A. The printed board 7 is in contact with the suction pad P1,
At this time, the suction pad P1 is in a sealed state. When the suction pad P1 is sealed, the suction force from the suction source reaches the suction chamber 2 through the suction passage 20. Then, the air in the suction chamber 2 is momentarily pushed up in the direction of arrow 30, but the movable valve 25 cannot be moved in the direction of arrow 30. Due to such suction, the inside of the suction chamber 2 becomes a vacuum eventually. That is, the print board 7 is sucked by the suction force of the suction source reaching the suction pad P1. This suction state is the same in the vacuum suction devices S3, S5 and S7 shown in FIG.

On the other hand, if the printed board has holes or dents, it will not be sealed even if the suction pad is applied to the holes or the like. The same applies to the case where the suction pad of the vacuum suction device is displaced and is not applied to the printed board.

In such a case, a vacuum suction device, for example, S
The operation No. 2 will be described with reference to FIGS. 5B, 5C and 5D. In this case, since there is a dent D1 on the printed board 7, the suction pad P2 is not sealed. If the suction pad P2 is not hermetically closed, the suction pad P2 continues to suck air from the dent D1 due to the suction force of the suction source. Then, the continuously sucked air passes through the air filter 26 and moves in the direction of arrow 30 through the suction chamber 2 and the suction passage 20. At this time, the movable valve 25 in the suction chamber 2 is also pushed up and moved in the direction of arrow 30 (FIGS. 5B and 5C). Then, the movable valve 25 continues to move in the direction of the arrow 30, and the upper surface thereof reaches the maximum reaching position Pa, blocking the suction chamber 2 and the suction passage 20 (FIG. 5D).

Therefore, the suction passage 20 is closed by the movable valve 25, and the suction passage 20 is evacuated. Then, thereafter, the suction pad P2 does not suck in the air in the recess D1. Movable valve 25 as described above
The movement of the same occurs also in the vacuum suction devices S4 and S6 shown in FIG.

Therefore, in the case of FIG. 4 in which one suction source uses a plurality of vacuum suction devices, it is possible to perform suction without lowering the pressure of the suction source as a whole.

[0012]

However, the vacuum suction device as described above has the following drawbacks. When a mechanism for automatically opening and closing the movable valve 25 as shown in FIGS. 4 and 5 is provided, for example, if the suction source is turned on before the suction pad hits the printed board, all the movable valves 2 are automatically turned on.
5 will be closed. Once the movable valve 25 is automatically closed, it is necessary to open the movable valve 25 again, that is, to input the OFF switch, which is troublesome.

In addition, when performing high-speed suction, conveyance operation, etc.,
If the suction pad is applied to the printed board during suction, the suction pad may be repelled on the printed board. If the suction source is turned on at the time of this rebound, the valves of all or part of the vacuum suction device may be closed. Therefore, since the vacuum suction device with the valve closed does not perform suction, the suction of the entire transport device is weak and the print board may drop during transport.

Therefore, it is necessary to turn on the suction pad for the first time after confirming that the suction pad has surely come into contact with the printed board, and it is necessary to control the timing of turning on the suction source.

Further, when sucking print boards having different heights, it is necessary to adjust the suction position (movement amount) of the suction pad depending on the print board each time. If this adjustment is not done properly, parts may not be adsorbed or may be damaged.

It is assumed that the adsorbate 7 is adsorbed as shown in FIG. 6A. At this time, the suction pad P8 sucks the print board 7 at the surface position L4. Next, the print board is changed and the suction pad P8 sucks the print board whose surface position is L3. In this case, suction is continued without adjusting the lowering position of the suction pad P8. Then, even when the print board whose surface position is L3 is sucked, the suction pad P8 tries to descend to the surface position L4 of the previous print board 7. And the surface position is L
3 is pressed by the suction pad P8 by a position difference L5 between the surface positions L3 and L4 and an unreasonable force is applied. Therefore, the printed board 7 may be damaged due to the pressing by the position difference L5. As described above, if the height at which the suction pad P8 descends during suction is not adjusted, the printed board may be damaged and yield or the like may be reduced.

Therefore, the present invention eliminates the need for precise control of the ON timing of the suction source, and can reliably adsorb an object to be adsorbed, that is, a printed board, and even for printed boards having different thicknesses. An object of the present invention is to provide a vacuum suction device that does not require height adjustment.

[0018]

According to a first aspect of the present invention, there is provided a vacuum suction device, which has a suction passage for transmitting a suction force of a suction source, a suction chamber having an opening communicating with the suction passage and in contact with an object to be suctioned, and a suction chamber. A movable valve provided in the chamber, which is normally held at a position where the suction passage is not blocked by gravity or a biasing means, and when suction is performed through the suction passage when the object to be attracted does not contact the opening. In a vacuum adsorption device having a movable valve that closes the suction passage, a bypass that communicates between the suction chamber and the suction passage at a flow rate sufficiently smaller than the suction passage when the suction chamber and the suction passage are closed by the movable valve. It is characterized by having means.

A vacuum suction device according to a second aspect is the first aspect.
The vacuum suction device is characterized by including a holding plate that holds the vacuum suction device and moves in a direction of approaching the object to be adsorbed, and elastic means provided between the holding plate and the vacuum suction device.

[0020]

In the vacuum suction device according to the first aspect, when the movable valve closes the suction chamber and the suction passage, the bypass means for communicating the suction chamber and the suction passage with a flow rate sufficiently smaller than the suction passage is provided. Has been.

Therefore, even when the object to be adsorbed does not come into contact with the opening, a small flow rate of air is flowing between the suction chamber and the suction passage, and it is possible to carry out adsorption only by abutting the object to be adsorbed. .

In the vacuum suction device according to claim 2,
An elastic means is provided between the vacuum suction device and a holding plate that holds the vacuum suction device and moves in a direction toward the object to be attracted. Therefore, when the moving distance of the holding plate is larger than the distance from the opening to the object to be attracted, the elastic means contracts.
That is, the contraction of the elastic means automatically adjusts the moving distance of the opening, and the opening appropriately contacts the object to be attracted.

[0023]

EXAMPLE A vacuum suction device is often used as a transfer device for transferring precision parts, such as transferring electronic parts to a mounting process. This is provided with one vacuum generator that is a suction source,
The printed board is sucked by using a plurality of vacuum suction devices. However, depending on the printed board, there may be holes or dents on the surface. If the suction pad hits such a hole or dent, the opening is not sealed. Therefore, air flows into the suction pad through the holes or dents, and the suction force of other vacuum suction devices is reduced. For this reason, the suction force of the entire transport device is reduced, and suction cannot be performed.

Therefore, there is a transfer device that automatically closes the valve of the vacuum suction device at a location where the suction pad is not sealed (see FIG. 4). That is, by closing the valve of the vacuum suction device in which the suction pad is not sealed, the vacuum state of the entire transport device is maintained and suction is performed. Operation control of such a vacuum suction device is performed by a movable valve provided in a suction chamber in the vacuum suction device.

An embodiment of the vacuum suction device according to the present invention, which is a vacuum suction device provided with such a movable valve, will be described with reference to the drawings. FIG. 1 shows a sectional view of an embodiment of the present invention. The vacuum suction device is provided with a suction passage 20, a suction chamber 2, and a suction pad P8. Also suction chamber 2
A movable valve 25 and an air filter 17 are provided inside.

FIG. 1A is a sectional view of the vacuum suction device of this embodiment when the vacuum generator is turned on before the suction pad hits the printed board due to an accident or the like. The movable valve 25 is a maximum reaching position P that closes the suction chamber 2 and the suction passage 20.
It is located at a. Therefore, the vacuum condition is such that the movable valve 25
It is blocked by and stops at the suction passage 20.

The movable valve reaching portion 6 in which the upper surface of the movable valve 25 in this embodiment shown in FIG. 1 is in contact with the upper wall of the suction chamber 2
An enlarged view of No. 5 is shown in Fig. 2. Here, the surface of the movable valve 25 is provided with fine irregularities 28 with reduced processing accuracy. Therefore, even when the upper surface of the movable valve 25 is in contact with the upper wall of the suction chamber 2, a small amount of air in the suction chamber 2 always flows into the suction passage 20 as indicated by an arrow 90.

Next, the operation of the vacuum suction device that suctions the printed board with the movable valve 25 closing the suction chamber 2 will be described with reference to FIGS. 1B and 1C. Printed board 7
When the suction pad P8 is brought into contact with the suction pad P8, the suction pad P8 is sealed by the printed board 7 (FIG. 1B). Then, external air does not flow into the suction pad P8. Even at this time, a small amount of air in the suction chamber 2 always flows into the suction passage 20 through the unevenness 28 on the movable valve 25 as shown in FIG. Therefore, the suction passage 2 in the vacuum state
The difference between 0 and the vacuum pressure in the suction chamber 2 gradually decreases.

However, the movable valve 25 is in the state shown in FIG. 1 for a while due to the suction force of the vacuum pressure of the vacuum generator, that is, at the maximum reaching position Pa (FIG. 1B). Eventually, the difference in vacuum pressure becomes small, and the suction force due to the vacuum pressure becomes
When the movable valve 25 cannot support the weight of the movable valve 25, the movable valve 25 gradually descends from the highest position Pa to the normal position Pb by its own weight (FIG. 1C). Then, the suction chamber 2 and the suction passage 20 are in communication with each other. Then, the air in the suction chamber 2 flows into the suction passage 20 and the vacuum pressures of the both become equal. Therefore, the printed board 7 contacting the suction pad P8 is surely sucked by the suction force of the vacuum generator.

Although the unevenness 28 is provided on the upper surface of the movable valve 25 as the bypass means in this embodiment, other bypass means, for example, FIG.
The bypass pipe 29 shown in FIG. 2 may be provided (see FIG. 2).

Next, FIG. 3 shows a carrying device provided with a height adjusting and adjusting function. A plurality of vacuum suction devices are provided in the main body 40 of the carrying device, and suction pads P8 and P9 project from the main body 40. Further, the main body portion 40 is connected to the holding plate 50 via the columns 36. Further support 3
The coil spring 35 is provided on the body 6, and the main body portion 40 also moves as the holding plate 50 moves when carrying. Then, the main body 40 moves up and down with respect to the holding plate 50.
The suction pad P provided on the main body 40 that moves up and down
8 and P9 come into contact with the printed board 7 to be adsorbed.

The operation of such a height adjusting mechanism will be described below. At the same time, it is assumed that the print board 7 at the surface position L1 is first sucked and then the print board at the surface position L2 is sucked. Then, the positions where the suction pads P8 and P9 contact the printed board 9 differ by the surface position difference LD between the surface position L2 and the surface position L1. However, in the present embodiment, the coil spring 3 is provided between the holding plate 50 and the moving plate 40 of the transfer device.
5 is provided and can be moved up and down. Therefore, the coil spring 35 contracts in the direction of arrow 100 to absorb the movement of the surface position difference LD.

That is, by providing the coil spring 35 between the holding plate 50 and the moving plate 40, it is possible to continuously attract print boards having different thicknesses without adjusting the position of the suction pad.

Although the coil spring is used as the elastic means in this embodiment, other elastic members may be used.

[0035]

In the vacuum suction device according to the first aspect of the present invention, even when the object to be adsorbed does not come into contact with the opening, a small flow rate of air is always flowing between the suction chamber and the suction passage, and Adsorption can be performed only by abutting.

Therefore, it is possible to automatically control the valve at the portion where the suction is not perfect and to perform the reliable suction. or,
Even if the opening does not come into contact with the object to be adsorbed for some reason after adsorption, it is possible to perform adsorption again if the object comes into contact with the opening, so it is necessary to control the operation timing of the suction source. Absent.

In the vacuum suction device according to claim 2,
When the moving distance of the holding plate is larger than the distance from the opening to the object to be attracted, the elastic means contracts. That is, the contraction of the elastic means automatically adjusts the moving distance of the opening,
The opening appropriately contacts the object to be attracted.

Therefore, it is possible to surely adsorb the object to be adsorbed without adjusting the moving distance of the holding plate in advance.

[Brief description of drawings]

FIG. 1 is a sectional view showing an operation of a vacuum suction device according to the present invention.

FIG. 2 is a partially enlarged sectional view of the vacuum suction device shown in FIG.

FIG. 3 is a side view showing a state in which a spring mechanism is provided in the transfer device.

FIG. 4 is a cross-sectional view showing an opening / closing operation when a plurality of conventional vacuum suction devices are provided in a transfer device to perform suction.

5 is a cross-sectional view showing the vacuum suction device shown in FIG.

FIG. 6 is a side view showing a surface position related to a change in the thickness of an object to be adsorbed.

[Explanation of symbols]

 2 ... Suction chamber 7 ... Printed board P8, P9 ... Suction pad 20 ... Suction passage 25 ... Movable valve

Claims (2)

[Claims] 1. A suction passage for transmitting a suction force of a suction source, a suction chamber having an opening communicating with the suction passage and in contact with an object to be sucked, and a movable valve provided in the suction chamber, the gravity valve or A vacuum suction device having a movable valve that is normally held at a position that does not close the suction passage by the biasing means and that closes the suction passage when suction is performed through the suction passage when the object to be attracted does not contact the opening. 2. The vacuum suction device according to claim 1, further comprising a bypass means for communicating between the suction chamber and the suction passage at a flow rate sufficiently smaller than the suction passage when the suction valve and the suction passage are closed by the movable valve. 2. The vacuum suction device according to claim 1, further comprising: a holding plate that holds the vacuum suction device and moves in a direction of approaching an object to be attracted; an elastic means provided between the holding plate and the vacuum suction device.
A vacuum suction device comprising: