JP3695176B2 - Air cylinder - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an air cushion mechanism of an air cylinder that is reciprocated by air.
[0002]
[Prior art]
As an actuator for a reciprocating operation in an electronic component mounting apparatus, an air cylinder having a simple structure and a compact structure is often used. The reciprocating operation of the air cylinder is controlled by the pressure and flow rate of the supplied air, and in general, an air cushion mechanism for absorbing shock is provided at the stroke end. This air cushion mechanism allows a part of the piston to be hermetically fitted into a fitting portion provided at an end portion in the cylinder at the stroke end, and is discharged from the air chamber formed by closing the fitting portion at this time. By reducing the amount of air to be absorbed, the impact at the stroke end is absorbed. Generally, an air cushion mechanism of a commercially available air cylinder is provided with an adjustable throttle, and a required cushion effect is obtained by adjusting the opening of the throttle according to the purpose of use.
[0003]
[Problems to be solved by the invention]
By the way, in the electronic component mounting process, a smooth operation with high impact and minimal impact is required. Therefore, an air cushion mechanism is indispensable for an air cylinder used in an electronic component mounting apparatus. For this reason, in the adjustment work of the electronic component mounting apparatus, the diaphragm adjustment work for obtaining the optimum air cushion effect is performed for each air cylinder. This operation has been conventionally performed by operating an adjustment screw of each air cylinder by an operator.
[0004]
However, an electronic component mounting apparatus uses an extremely large number of air cylinders, and many air cylinders of the same purpose are used. Depending on the type of apparatus, 100 or more of the same one may be used per apparatus. is there. For this reason, when starting up the apparatus after assembly or during maintenance adjustment, the air cushion diaphragm adjustment work requires a great deal of time and effort.
[0005]
Therefore, an object of the present invention is to provide an air cylinder that does not require an aperture adjustment operation in an air cushion mechanism.
[0006]
[Means for Solving the Problems]
The air cylinder according to claim 1 is an air cylinder that reciprocally drives a piston fitted to the cylinder by supplying air into the cylinder, the fitting portion provided at an end portion in the cylinder, A protrusion provided on the piston at a stroke end of the reciprocating motion of the piston and hermetically inserted into the insertion portion; A fixed throttle that is provided in the air introduction hole and restricts discharge of the air in the air chamber to a predetermined amount, and the fixed throttle is an opening portion of a predetermined diameter provided in a plate member, and the plate The member is pressed and fixed on the lower surface of the screw member .
[0008]
According to the present invention, the throttle of the air cushion mechanism of the air cylinder is a fixed throttle having a predetermined opening determined in advance, so that the throttle adjustment work after the device is incorporated is not required.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings. 1 is a perspective view of a mounting head of an electronic component mounting apparatus using an air cylinder according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of the mounting head of the electronic component mounting apparatus using the air cylinder, and FIG. FIG. 4 is a sectional view of a cushion orifice of the air cylinder.
[0010]
First, the mounting head of the electronic component mounting apparatus will be described with reference to FIGS. 1 and 2, the mounting head 1 is mounted on a Z-axis table 3 driven by a Z-axis motor 2. The mounting head 1 includes a lifting block 4 coupled to a box-shaped member 5, and six air cylinders 6 are disposed on the upper surface of the box-shaped member 5 at equally spaced positions on the circumference.
[0011]
As shown in FIG. 2, the air cylinder 6 is a double rod type, and the rod 6a protrudes in both the upper and lower directions. The downwardly projecting rod 6a is rotatably coupled to the nozzle lifting / lowering rod 7, and the nozzle lifting / lowering rod 7 is inserted into the slide unit 8 and connected to the nozzle 9 mounted at the lower end. By vacuum suction from the lower end portion 10 of the nozzle 9 by suction means (not shown), the nozzle 10 sucks the electronic component into the suction hole of the lower end portion 10.
[0012]
An electromagnetic valve 11 is connected to the supply / exhaust port of the air cylinder 6 via an air pipe, and air is supplied to the electromagnetic valve 11 via a regulator 12. The direction of air is switched by operating the solenoid valve 11, and the air cylinder 6 moves up and down according to the direction of the supplied air. As described above, the air cylinder 6 is for vertically moving the nozzle 9 that sucks the electronic component. The vacuum suction of the electronic component is performed at the bottom dead center, and the rod 6a protrudes upward to cause the nozzle 9 to move upward. In this state, the electronic component is moved down to the mounting point and then lowered again to mount the electronic component that has been suctioned and held at the bottom dead center at the mounting position, and the suction is released and mounting is performed.
[0013]
In recent years, electronic components such as semiconductor chips have become very small in size, and extremely precise operation control is required for adsorption and handling during mounting. Furthermore, in the electronic component mounting process, improvement in mounting work efficiency is required, and the mounting tact time tends to be shortened. That is, an air cylinder that drives the electronic component suction nozzle up and down is required to have characteristics that enable both precise operation control and high-speed operation.
[0014]
The air cylinder 6 used for applications requiring such functions and characteristics will be described with reference to FIGS. In FIG. 3, the air cylinder 6 includes a cylinder tube 20 constituting a cylinder as a fixed portion, and a cylinder head 21 fixed to both ends of the cylinder tube 20. A piston 23 which is a reciprocating portion is fitted to the cylinder tube 20, and rods 6 a which protrude outward and reciprocate together with the piston 23 are coupled to both sides of the piston 23. Seal members 22 and 24 are respectively attached to the sliding portion between the rod 6a and the cylinder head 21 and the sliding portion between the piston 23 and the inner surface of the cylinder tube 20 to seal the sliding gap.
[0015]
Cushion portions 25 that are protrusions are provided on both sides of the piston 23, and a seal member 26 is attached to the cushion portion 25. The cylinder head 21 which is the end of the cylinder is provided with a fitting portion 27 corresponding to the outer diameter of the cushion portion 25. When the piston 23 moves to the vicinity of the stroke end, the cushion portion 25 is fitted into the fitting portion 27. At this time, the inside of the fitting portion 27 is kept airtight by the seal member 26, and an airtight air chamber 28 is formed.
[0016]
The air chamber 28 is connected to the throttle portion 30 via the air guide hole 29, and the throttle portion 30 includes an orifice ring 32 and a fixing screw member 31 that fixes the orifice ring 32. The throttle portion 30 communicates with the air supply / exhaust port 34 through the air guide hole 33. As shown in FIG. 4, the orifice ring 32 is provided with an orifice 32 a having a hole diameter d, and a cross groove 31 a is provided on the lower surface of the screw member 31 that presses and fixes the orifice ring 32.
[0017]
In a state where the screw ring 31 is pressed against the orifice ring 32 by the screw portion 31b and the orifice ring 32 is fixed, the orifice 32a communicates with the cross groove 32a, and therefore, the gap between the air introduction hole 29 and the air introduction hole 33 is via the orifice 32a. Communicate. The air discharged from the air chamber 28 is throttled by the orifice 32a, and the throttle effect at this time is determined by the orifice diameter d. That is, the orifice 32a, which is an opening portion of a predetermined diameter provided in the orifice ring 32, which is a plate member, is a fixed throttle that restricts the discharge of air in the air chamber 28 to a predetermined amount.
[0018]
Next, the function of the throttle unit 30 during the operation of the air cylinder 6 will be described. In the figure, when the piston 23 moves to the vicinity of the stroke end, the orifice portion 25 is fitted into the fitting portion 27, and the air chamber 28 in the fitting portion 27 is sealed by the seal member 26. As the piston 23 further approaches the stroke end, the air in the air chamber 28 is compressed and discharged to the air supply / exhaust port 34 through the air introduction hole 29, the throttle portion 30 and the air introduction hole 33.
[0019]
The flow rate of the air discharged at this time is determined by the orifice diameter d of the throttle portion 30, and the discharge speed of air from the air chamber 28 can be controlled by appropriately setting the orifice diameter d. Therefore, the speed of the piston 23 at the stroke end can be reduced, and the piston 23 can be smoothly stopped without causing an impact at the stroke end. Since this cushion effect is determined by the orifice diameter d, the cushioning characteristic does not change even during the long-term use of the air cylinder, and the throttle method using a conventional adjustment needle that requires regular readjustment work. Compared to the above, a stable cushion effect can be obtained.
[0020]
As described above, by using a fixed throttle as the throttle of the cushion mechanism of the air cylinder 6 and preferably using the orifice ring 32 having a hole in the plate member, the air cylinder for the same application is manufactured in advance and has the same standard. By simply mounting the orifice ring provided with the aperture portion, it is possible to omit the diaphragm adjustment work conventionally required. This labor-saving effect is extremely great for an apparatus that uses a large number of air cylinders of the same standard for the same application, such as the electronic component mounting apparatus described above.
[0021]
In the present embodiment, an example of an air cylinder used for a mounting head of an electronic component mounting apparatus is shown. However, the present invention is not limited to this, for example, a tape feeder for supplying electronic components. The present invention can be applied to an air cylinder that is used for tape pitch feed driving and requires high-speed and high-accuracy operation and many are used in the same application.
[0022]
【The invention's effect】
According to the present invention, the throttle of the air cushion mechanism of the air cylinder is a fixed throttle having a predetermined opening obtained in advance, so that it is not necessary to adjust the throttle after the device is installed and is stable for a long time. The cushioning effect can be maintained.
[Brief description of the drawings]
FIG. 1 is a perspective view of a mounting head of an electronic component mounting apparatus using an air cylinder according to an embodiment of the present invention. FIG. 2 is a mounting of an electronic component mounting apparatus using an air cylinder according to an embodiment of the present invention. FIG. 3 is a partial sectional view of an air cylinder according to an embodiment of the present invention. FIG. 4 is a sectional view of a cushion orifice of the air cylinder according to an embodiment of the present invention.
6 Air cylinder 6a Rod 20 Cylinder tube 23 Piston 25 Cushion part 27 Insertion part 28 Air chamber 29, 33 Air guide hole 30 Restriction part 32 Orifice ring 32a Orifice

Claims (1)

An air cylinder that reciprocally drives a piston fitted to the cylinder by supplying air into the cylinder, the fitting being provided at an end in the cylinder, and a reciprocating motion of the piston provided in the piston. A protrusion that is airtightly inserted into the insertion portion at the stroke end, a gas introduction hole that communicates the air chamber formed by fitting the projection into the fitting portion to the outside, and provided in the air conduction hole. A fixed throttle that restricts the discharge of air to the outside by a predetermined amount, and the fixed throttle is a hole portion of a predetermined diameter provided in the plate member, and the plate member is pressed by the lower surface of the screw member. An air cylinder characterized by being fixed .

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