JPH0747269B2 - Vacuum chuck and suction holding method using the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum chuck and a suction holding method using the same.

[0002]

2. Description of the Related Art Conventionally, in a vacuum chuck that opens and closes a suction hole with a valve, if foreign matter such as chips adheres to the gap between the valve and the inner wall of the suction hole, the sealing of the valve deteriorates and the degree of vacuum decreases and the suction force is lost. There was a problem.

[0003]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and does not cause a decrease in vacuum degree due to the adhesion of foreign matter such as chips and the like, and always holds the object to be held with a stable suction force. It is intended to be adsorbed and held by.

[0004]

A first aspect of the present invention for solving the above problems is to provide a retractable elastic valve in a valve chamber provided with an arc-shaped valve seat having a small hole communicating with the vacuum chamber. The elastic valve is characterized in that a plurality of fine holes which can be expanded in diameter are formed in the elastic valve except for a small hole shielding portion which shields a small hole of the valve seat. The second invention is an elastic valve of the vacuum chuck, the elastic
When the valve is stretched due to the pressure difference between the inside and the outside, the elastic valve is transparently installed.
The diameter of the fine holes becomes larger and the pressure difference between inside and outside becomes smaller,
As a result, when the elastic valve contracts, the diameter of the fine holes decreases.
Repeating a series of movements that increases the internal and external pressure difference
Thus, the object to be held is sucked and held while being vibrated.

[0005]

The present invention will be described in detail below with reference to the drawings. Reference numeral 1 denotes a vacuum chamber, and a top plate portion of the vacuum chamber 1 is provided with a large number of valve chambers 3 provided with arc-shaped valve seats 2. 4 is a small hole formed in the arc-shaped valve seat 2, and the small hole 4 is a vacuum chamber 1
And the valve chamber 3 are communicated with each other. 5 is a large number of suction holes 6
Is a transparent suction plate, and the suction hole 6 of the suction plate 5 is connected to the valve chamber 3. Reference numeral 7 denotes a stretchable elastic valve provided in the valve chamber 3. The elastic valve 7 is provided with a plurality of fine holes 9 except for a small hole shielding portion 8 that closes the small hole 4. The diameter of the hole 9 is increased according to the expansion and contraction of the elastic valve 7. Reference numeral 10 denotes an exhaust hole of the vacuum chamber 1.

[0006]

With this structure, when the vacuum chamber 1 is at atmospheric pressure, there is no pressure difference between the inside and the outside of the elastic valve 7, so that the fine holes 9 are maintained in a state in which they are hardly vented as shown in FIG. But,
When the vacuum chamber 1 becomes a negative pressure and the held body is placed on the suction hole 6 of the suction plate 5, a negative pressure acts on the elastic valve 7 and the elastic valve 7 is sucked toward the valve seat 2 side. As it is stretched and stretched, it is shown in FIG.
As described above, the diameter of the fine holes 9 is expanded, and the air in the suction holes 6 is sucked and exhausted into the vacuum chamber 1 through the small holes 4. As a result, when the pressure difference between the inner and outer pressures of the elastic valve 7 becomes smaller, the contraction force of the elastic valve 7 itself wins and the elastic valve 7 contracts. The valve 7 will be extended again to the valve seat 2 side. In this way, the elastic valve 7 vibrates as shown in FIG. 4, so that the intrusion of foreign matter such as chips generated by cutting or the like is prevented.

Further, even if chips enter the valve chamber 3 through the fine holes 9, the contact area between the valve seat 2 of the valve chamber 3 and the elastic valve 7 is large, so that the vacuum degree of the valve chamber 3 is lowered. There is no.
When the suction hole 6 is opened to the outside, the suction hole 6
The air sucked in further flows between the arc-shaped valve seats 2 through the expanded fine holes 9 of the elastic valve 7 and is exhausted to the vacuum chamber 1 through the small holes 4. At this time, as shown in FIG. As shown, the flow velocity of the air flow flowing on the valve seat 2 side is faster than the air flow flowing on the suction hole 6 side of the elastic valve 7, so that a negative pressure is generated on the valve seat side 2 and the small hole shield of the elastic valve 7 is expandable. Since the portion 8 comes into close contact with the valve seat 2 and shields the small hole 4 of the valve seat 2, the vacuum degree of the vacuum chamber 1 does not decrease due to the inflow of a large amount of air, and the suction force is always maintained. The object to be held is adsorbed and held accurately.

[0008]

As is apparent from the above description, the present invention has the expandable elastic valve formed with the fine hole capable of expanding the diameter. Therefore, the elastic valve vibrates during the adsorption of the object to be held and is cut by the cutting. Prevents chips from entering through fine holes,
Even if foreign matter enters through the fine holes, the seal area of the elastic valve and the valve seat is large, so that the foreign matter does not incompletely seal the elastic valve. Moreover, when the vacuum pump is stopped, the fine holes of the elastic valve are almost closed, and the accumulated cutting oil and the like do not flow into the vacuum chamber through the fine holes, which adversely affects the vacuum pump. As a vacuum chuck and a suction holding method using the vacuum chuck, which have solved the conventional problems, they are extremely significant in that they contribute to industrial development.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of the present invention.

FIG. 2 is a sectional view of the elastic valve showing a state in which a negative pressure is not applied to the vacuum chamber.

FIG. 3 is a sectional view of the elastic valve showing an initial state in which a held body is sucked into the suction hole.

FIG. 4 is a sectional view showing a vibrating state of the elastic valve when the held body is sucked.

FIG. 5 is a sectional view of the elastic valve similarly showing a state in which the suction hole is opened to the outside.

[Explanation of symbols]

 1 vacuum chamber 2 valve seat 3 valve chamber 4 small hole 7 elastic valve 8 small hole shield 9 fine hole

Claims (2)

[Claims] 1. A retractable elastic valve is provided in a valve chamber having an arc-shaped valve seat through which a small hole communicating with the vacuum chamber is provided, and the elastic valve is provided with a small hole shielding portion for shielding the small hole of the valve seat. Except for the above, a vacuum chuck is characterized by forming a plurality of fine holes that can be expanded in diameter. 2. The elastic valve of the vacuum chuck according to claim 1, wherein the elastic valve is transparently provided on the elastic valve when the elastic valve is extended due to a pressure difference between the inside and outside.
The inside and outside pressure difference is small due to the large diameter of the fine holes
As a result, when the elastic valve contracts, the diameter of the fine holes becomes small.
Repeat a series of movements that increase
A suction-holding method, wherein the held body is sucked and held while being vibrated by being returned .