JPS63293306A - Cylinder with cushion - Google Patents

Abstract

PURPOSE:To prevent the damage of a part, a product, and the like by connecting a piston and a piston rod through a compression spring in a cylinder with cushion which is used for an industrial robot for assembling works. CONSTITUTION:A piston 14 and a piston rod 13 are connected through a compression spring 16. As a result, the piston 14, the piston rod 13, and the compression spring 16 are operated as a unitary body in a normal condition. On the other hand, in a misassembled condition where the unit strikes an obstacle, for example, the piston rod 13 slides bending the compression spring 16 separately from the piston 14, and the damage of a part, a product, and the like can be prevented.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a cushioned air cylinder used in an assembly industrial robot, and more specifically to a cushioned air cylinder used in fitting and assembly work. be.

(Prior Art) Conventionally, when automating an assembly operation, the basic operation is to assemble from above, and the product is designed based on this from the product design stage.

A conventional air cylinder for an industrial robot used in automatic assembly work will be explained with reference to FIGS. 6 and 7.

FIG. 6 is an overhead view of the automatic assembly line, in which a parts supply device 2 is placed on the front side of the belt conveyor 1, and a robot 3 is placed on the opposite side. A product 5 having an installation shaft 4 is placed on the belt conveyor 1, and is brought to an assembly position and stopped. The arm 7 of the robot 3, which has an air cylinder 6 attached to its tip, extends, and the air cylinder 6 comes to rest above the component extraction port of the component supply device 2. On the other hand, the parts 8 placed in the hopper of the parts supply device 2
teeth,! They are arranged in 11 rows and sent out one by one to the parts extraction port. The air cylinder 6 is operated, the piston rod 9 is lowered, the chuck 10 attached to the tip thereof grabs the part 8, and the product 5 which has risen and is stopped on the belt conveyor 1 is attached to the shaft 4. The parts 8 are then carried upwards and lowered again to be assembled by fitting the parts 8 onto the shaft 4.

FIG. 7 is an enlarged sectional view of the main parts of the parts gripping part of the robot 3.
The piston rod 9 of the air cylinder 6 has a
Slide rods 10a and 10b having heads that slidably fit into the guide holes 9a and 9b are attached to the guide holes 9a and 9b, and the back side of the chuck 10.
A compression coil spring 11 housed in a bottomed hole at the center of the head of the piston rod 9 urges the chuck 10 downward to provide a cushioning function.

If there is an error in positioning, the component 8 will not fit onto the shaft 4 during installation, and the chuck 10 that grips the component 8 at the tip of the shaft 4 will be pushed up, but the compression coil spring 11 will contract and the guide hole 9a will be pushed up. The sliding rods 10a and 10b fitted to the parts 8 and 9b slide, and the chuck 10 retreats, and the part 8
Or prevent damage to the product 5.

(Problems to be Solved by the Invention) However, in the above configuration, there are problems in that not only the number of parts is large and the cost is high, but also the chuck portion becomes large.

The present invention solves the above problems and provides a small cushioned cylinder with a built-in cushioning mechanism.

(Means for Solving the Problems) In order to solve the above problems, the present invention provides an air cylinder provided with compressed air supply ports at both ends.

A slidable piston is slidably guided by bearings provided at both ends of the air cylinder, and a slidable piston rod is hermetically accommodated in the through hole of the piston, and the piston and screw are slidably guided by bearings provided at both ends of the air cylinder. A compression spring is inserted between the two rods to transmit the movement of the piston to the piston rod.

(Function) According to the above configuration, 1. During normal operation, the movement of the piston is transmitted to the piston rod via the compression spring and moves simultaneously, but the piston rod collides with an obstacle and the movement is blocked. In this case, the compression spring is deflected and the piston rod is retracted regardless of the movement of the piston. Therefore, parts, products, etc. will not be damaged by the thrust of the piston.

(Embodiment) An embodiment of the cushioned cylinder according to the present invention will be described with reference to FIGS. 1 to 5.

FIG. 1 is a front sectional view of the embodiment, and the cushioned cylinder has compressed air supply ports 12a and 12b at both upper and lower ends.
The piston rod 13 is slidably fitted into the bearing holes 12c and 12d provided at both ends of the air cylinder 12, and the piston rod 13 is slidably fitted into the cylindrical sliding inner diameter surface 12a of the air cylinder 12. and a through hole 14 in the center through which the piston rod 13 is inserted airtightly and slidably.
a piston 14 and the above-mentioned piston rod 13
Stopper 15 fitted to the stepped part provided at the lower end and the upper end of
It consists of a compression coil spring 16 inserted between a piston 14 and a piston 14 mounted close to each other. Note that the bearing holes 12c and 12d of the air cylinder 12, the inner diameter surface of the through hole 14a of the piston 14, and the outer diameter surface of the piston 14 are provided with packings 17, 18, 19 and 19, respectively, which slide while maintaining airtightness. 20 is attached.

The operation of the cushioned cylinder configured in this way will be explained.

In the cushioned cylinder shown in FIG. 1, a chuck 21 is attached to the tip of the piston rod 13.

A cushioned cylinder mounted vertically on the tip of a robot arm (both not shown) is moved by the robot to a position directly above a component ejection opening (both not shown) of a component supply device. First, the fingers 22 of the chuck 21 open, and then,
When compressed air is sent from the air supply port 12a at the upper end of the air cylinder 12, the piston 14 slides and descends. At the same time, the piston rod 13 is pushed down via the compression coil spring 16.

Next, the chuck 21 operates, and its fingers 22 grip the outer diameter of the protrusion of the component 23. During this time, compressed air is being supplied from the air supply port 12a at the upper end, but when gripping is finished, the air supply is switched to the air supply port 12b at the lower end, and the piston 14 rises. The piston 14 is connected to the biscuit rod 1 via the stopper 15.
Push up 3. In this state, the robot operates and moves directly above the product 24 on the conveyor (not shown). When the movement is completed, the air supply is switched again to the air supply port 12a at the upper end, the piston rod 13 is pushed down, and the chuck 2
To attach the product 24, the gripped part 23 of 1 is fitted onto the shaft 24a and assembled. 0 When the assembly is completed, the fingers 22 of the chuck 21 open, the supply air is switched again to the air supply port 12b at the lower end, and the piston rod 13 is pulled up. .

FIG. 2 shows the state when the above-mentioned fitting and assembly is completed.

As shown in FIG. 3, due to variations in the parts 23 or products 24 or other causes, the product 24 cannot be mounted on the shaft 24a.
If the part 23 cannot be fitted to the piston rod 13,
is pushed up while bending the compression coil spring 16 regardless of the piston 14, so one part 23 or product 24
damage can be prevented.

In addition, in this embodiment, as shown in FIG.
7.18 and 19 are used, the precompression force of the compression coil spring 16 is equal to the above three packings 17.18.
and 19 sliding resistance. Therefore, depending on the part or product, if it is damaged by an extremely weak force that is smaller than the sum of the bending force of the compression coil spring 16 and the sliding resistance of the packings 17, 18 and 19, the sliding gap may be removed without using the packing. It is sufficient to maintain airtightness by keeping the pressure to a few micrometers, and furthermore, use a compression coil spring 16 with a small spring constant to reduce the amount of preliminary compression. However, in this case,
Since the fitting gap between the through hole 14a of the piston 14 and the piston rod 13 is small, it is necessary to strictly suppress the perpendicularity of the lower body abutment surface 12f of the air cylinder 12. FIG. 4 is a cross-sectional view of a main part showing a case where the perpendicularity of the cylinder thrusting surface 12f is poor. The piston 14 is pressed against the cylinder thrusting surface 12f which has a poor perpendicularity, and in order to learn from this, the piston 14 is attached to the piston rod 13 and tilts, penetrating. The piston rod 13 is located at the symmetrical portions of both ends of the hole 14a.
This will force the Therefore, the sliding resistance increases significantly and the cushion mechanism becomes inoperable.

Therefore, when used for normal assembly work, it is desirable that the length of the piston 14 be larger than the diameter, and that the piston 14 be guided by the outer diameter surface.

FIG. 5 is a perspective view of a cushioned cylinder according to the present invention provided with a rotation prevention mechanism and an assembly error detection mechanism.
The cylinder with a cushion is equipped with a detent rod 25 parallel to the upper end of the piston rod 13, and a detent rod 25 mounted on the upper end of the air cylinder 12.
A guide groove 12f is provided to engage with the guide groove 12f. Furthermore, an L-shaped light shielding plate 26 is attached to the side surface of the upper end of the piston rod 13, and two photosensors 27 and 2 are mounted on the side surface of the air cylinder 12 to detect the movement of the light shielding plate 26.
8 is divided into upper and lower parts.

(Effects of the Invention) As explained above, according to the present invention, the piston and the piston rod, which are slidable relative to each other, are connected via the compression spring, so that they move as one body during normal operation and do not interfere with obstacles. In the event of an assembly error, the compression spring is bent and the piston rod slides separately from the piston, so there is no damage to parts or products, and the compression spring is built-in.

Since the structure is simple, it is a small and inexpensive cylinder with a sheath.

[Brief explanation of drawings]

Fig. 1 is a front sectional view of a cylinder with a cushion according to the present invention, Figs. 2 and 3 are front sectional views for explaining its operation, and Fig. 4 is a state in which an air cylinder with poor shape accuracy is used. FIG. 5 is a perspective view of a cushioned cylinder according to the present invention equipped with a rotation prevention and assembly error detection mechanism, and FIG. 6 is an assembly line for explaining assembly work using a conventional cylinder. 7 is a cross-sectional view of a conventional cushioned cylinder. 1... Belt conveyor, 2... Parts supply device,
3...Robot, 4,24a...Axle for installation, 5
．． 24...Product, 6.12...Air cylinder, 7.
・・Arm, 8,23・・Parts, 9,13・
...Piston rod, 9a, 9b...Guide hole,
10.21-...Chuck, 10a, 10b-
sliding rod. 11, 16... compression coil spring, 12a, 12
b...Air supply port, 12c, 12d...Bearing hole, 1
2e... Cylindrical sliding circular diameter surface, 12f... Trunk thrusting surface, 12g... Guide groove, 14... Piston, 14
a...Through hole, 15...Stopper, 17.18
．． 19゜20... Packing, 22... Chuck finger, 25... Stopping rod, 26... Light shielding plate, 27゜28... Photo sensor. Patent applicant: Matsushita Electric Industrial Co., Ltd.
Mouth 12C, 12d -1-Bearing pull-in 12e-Cylindrical eyebrow trimmer, dI! 113-hi°stonro・1. Do 14
-2-Bikutono 14a-Kantatsurei 15-St"l Tsuma 16-, -ffJ! Coil 1 piece'η17.18.1
9.20-Pa,,kin Fig. 2 Fig. 3 12-Air 5 cylinder 12a, 12b -J tip
13. -Head-in throat/throat 14-Piston 15-
Strike, 7pa 16-0 Pressure Yu Coil 1 Gowa 21-1 Su4
・Tsuku 22-Finger 23 Part 24-Product 24
a-Installation j axle Fig. 4 12-, F cylinder 12f-, body butt S city 13
-H°in Donoro・, Do 14, -Goston 14 a
-1j$LL 20- / Figure 5 12-Air Relay) 129-Guide groove 13-Piston port, 21-0±7, 2500 times Seal stop port, 7 3. -Greetings 2nd floor 28-Photo sensor Figure 6

Claims (2)

[Claims] (1) An air cylinder having air supply ports at both ends, a piston rod that slidably fits into the bearing holes at both ends, and a piston rod that slidably fits into the inner diameter surface of the air cylinder, and A piston that is slidably fitted to the piston rod;
A cushioned cylinder comprising a compression spring inserted between the piston rod and the piston, and transmitting movement of the piston to the piston rod via the compression spring. (2) The cushioned cylinder according to claim (1), wherein the length of the piston is larger than its outer diameter, and the cylinder slides while being guided by the inner diameter surface of the air cylinder.