JPH0369643B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotary hydraulic cylinder for chucking in a machine tool.

FIG. 1 shows a conventional device for this,
1 is a sleeve having a hydraulic oil supply pipe port 1a and a return pipe port 1b (which are alternately reversed) and a drain outlet 1c; 2 is a cylinder body including a rotary valve 2a, a cylinder box 2b, and a cylinder; The piston 3 is slidably housed in the cylinder case. At this time, oil passages 4a and 4b are provided in the rotary valve 2a, and oil passages 5a and 5b are provided in the cylinder case 2b and cylinder cover 2c, respectively, and these oil passages are provided in the sleeve 1. The pressure oil is communicated with the feed pipe port 1a and the return pipe port 1b, which are connected to each other, to feed and discharge pressure oil into the cylinder box.Specifically, if 1a is the feed side, the pressure The oil enters the chamber A side of the cylinder box through oil passages 4a, 5a, and 5b and moves the piston 3 in the direction of arrow v, whereas the pressure oil that had entered the chamber R side flows through oil passage 4b. The water is then returned to the tank (not shown) through the return pipe port 1b. This operation is performed by switching a solenoid valve (not shown) to the feed pipe port 1.
The reverse operation is achieved by changing the flow of pressure oil to a and the return pipe port 1b.Specifically, assuming that the chuck means (not shown) is gripped by sliding of the piston 3 in the direction of the arrow v, the chuck For release, 1b becomes the pressure oil supply side and arrow w
This is done by sliding in the direction.

5 is a guide pin fixed to the piston 3, and during the sliding operation, both ends P and P' of the guide pin 5 are guided into pin holes 6a and 6b drilled in the cylinder cover and the rotary valve side. As a result, free rotation is inhibited. In the drawings, 7a and 7b are ball bearings, and 8 is a sleeve cover.

As mentioned above, in the conventional device, a part of the rotary valve that supplies and discharges pressure oil into the cylinder casing protrudes toward the sleeve side, which serves as the tank port.
In addition, the cylinder device is rotatably supported on a shaft within the sleeve, and therefore the overall length l of the cylinder device is relatively large, which has been a bottleneck in making it more compact and saving space. Furthermore, a large value of l is not preferable in terms of vibration damping effect.

The present invention aims to solve and eliminate the above problems, and is characterized in that the center of the piston is formed into a hollow or hollow tube structure, while the sleeve is fixed in position. The center part is formed into a protrusion that protrudes a certain length toward the piston, and a pressure oil supply path and return path are bored in the protrusion to fit into the cavity or hollow pipe of the piston, and the front surface of the cylinder casing is The lid has a central portion formed into a tube that projects a certain length toward the piston on the outer periphery of the sleeve protrusion, and has an oil passage that communicates with the inside of the tube with the supply path and return path on the sleeve side. This is because we have established

Hereinafter, embodiments of the present invention will be described based on the drawings from FIG. 2 onwards.

In FIGS. 2A and 2B, 10 is a sleeve connected to a tank port, and a vertical portion 10a is provided with a pressure oil supply pipe 11a and a discharge pipe 11b, which are used for tightening or discharging the chuck. It is the same as before that 11c alternates with the release operation and that 11c is a drain outlet port, but the sleeve 10 is fixed in position and has a shape in which the central part protrudes a certain length in the horizontal direction. The above-mentioned pipes 11a,
Oil passages 12a and 12b and a drain passage 12c for the oil passages 11b and 11c are respectively bored.

Reference numeral 13 denotes a cylinder lid, which in this example is a tube body 13b whose central portion protrudes a certain length toward the piston, and is rotatably supported on the horizontal portion 10b of the sleeve 10 via ball bearings 14a, 14b. Become. 15a and 15b are oil passages bored in the pipe body 13b;
The oil passage 12a on the side communicates with the oil passage 12b on the latter side.

16 is a cylinder case, 17 is a piston therein, and a cavity 18 is formed in the center thereof into which the horizontal part 10b of the sleeve 10 and the tube body 13b of the rotary valve 13 are fitted; 22 reciprocates in chambers A and B while in contact with the tube body 13b and the inner wall surface of the cylinder 16 via O-rings 19, 20 and 21.
and 23 are through holes and notches for feeding and discharging pressure oil from the oil passages to and from each chamber (a) and (b).

Specifically, the oil from the oil passage 12a is transferred to the oil passage 15a.
It flows out into the cavity 18 through the hole 22 through the gap 24 formed between the outer periphery of the tubular body 13b and the cavity 18, and is then sent into the chamber 1 through the through hole 22. On the other hand, the oil in the chamber is returned into the tank from the discharge pipe via the oil passages 15b and 12b.

As can be seen in the drawings, in the device according to the invention both bearing means 14a and 14b for the sleeve 10 are provided within the cylinder body. In the drawings, 25 is a cover that covers the piston side of the bearing 14b (however, an oil passage 26 for communicating with the cavity 18 is provided at a location corresponding to the oil passage 15a), and 27 is a cover that covers the piston side of the bearing 14b. The guide pins 28 and 29 fixed to the piston 17 are pin holes bored in the cylinder cover 13 and the cylinder casing 16 facing the guide pin 27, and when the piston 17 reciprocates, the guide pins 27 Both ends P, P' of are guided into these pin holes 28, 29, thereby preventing free rotation.

In this example, in order to slide the piston 17 in the direction of arrow v and tighten the chuck means (not shown), pressurized oil sent from the supply pipe 11a is applied to the oil pipes 12a and 15.
This is done by sending the oil into the chamber A through the oil passages 15b and 22 and returning the oil in the chamber A to the tank side through the oil passages 15b and 12b. Arrow in the opposite direction
To release the discharge pipe by sliding it in the direction
By setting b to the pressure oil feeding side, that is, pressure oil is sent to chamber RO via oil passages 12b and 15b, whereas pressure oil in chamber ② is sent to oil passages 26 and 15.
a, 12a, etc., and then returned to the tank side from the feed pipe 11a.

As described above, the present invention forms a hollow or hollow structure in the center of the piston, and a sleeve having an oil passage is fitted into the cavity or hollow pipe of the piston, and is fixed so that it does not move on the outside of the sleeve. The lid on the front surface of the cylinder casing has a center portion formed into a tube that protrudes a certain length toward the piston on the outer circumferential surface of the sleeve protrusion, and the sleeve side is fed into the inside of the tube. As a result of providing an oil passage that communicates with the return passage and the return passage, the cylinder length l can be reduced to approximately 1/2 to 1/3 of the conventional size, making the entire lathe device more compact and space-saving. It is a great contribution. In addition, the small cylinder length l also provides an excellent vibration damping effect for this part.

In addition, since the sleeve 10 does not move, the above-mentioned total length can be shortened, and the device is well-balanced, does not pinch the hands, and can prevent vibration.

[Brief explanation of drawings]

Figure 1 is a vertical sectional view showing a conventional device, Figure 2A,
B shows the device of the present invention, A is a longitudinal sectional view, and B is a longitudinal sectional view.
is a side view. 1a...Feed pipe port, 1b...Return pipe port, 2...
Cylinder body, 3...Piston, 10...Sleeve, 12a, 12b, 12c...Oil passage, 13...
... Cylinder lid, 14a, 14b ... Ball bearing, 15a, 15b ... Oil passage, 16 ... Cylinder casing, 17 ... Piston, 18 ... Cavity,
19, 20, 21... O-ring, 27... Guide pin, 34... Guide tube.

Claims (1)

[Claims] 1. The inner center of the piston that slides within the cylinder casing is formed into a hollow or hollow tube structure, while the sleeve is fixed in position and the center portion is formed into a protrusion that protrudes a certain length toward the piston, A supply path and a return path for pressure oil are bored in the protrusion, and the pressure oil is inserted into the cavity or hollow tube of the piston, and the lid on the front surface of the cylinder casing has its center portion on the outer periphery of the sleeve protrusion on the piston side. A fluid pressure cylinder for chucking in a machine tool, characterized in that it is formed into a tubular body that projects a certain length from the cylinder, and has an oil passage inside the tubular body that communicates with the feed passage and the return passage on the sleeve side. .