JP2571220Y2 - Turntable fixing device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a turntable fixing device provided in a machine tool or the like.

[0002]

2. Description of the Related Art Conventionally, there is a multi-function machine tool in which turning, cutting, drilling, and the like can be performed by a single device, provided with a turntable. In the above-mentioned machine tools, when performing turning, the turntable on which the work is mounted is rotated to process the work, but when performing cutting or drilling, the turntable on which the work is mounted is rotated by a fixing device. Is fixed and processed. In addition, since high-precision machining is difficult if the turntable moves during machining, the rotation of the turntable is conventionally fixed by a fixing device as shown in FIGS. 1 and 2. That is, a disk b is provided at the lower end of a support shaft a rotatably supporting the turntable, and a clamp cylinder c having a plurality of pressure chambers f at equal intervals on the same circumference above and below the disk b. Is installed. In the pressure chambers f of the clamp cylinders c, pistons e having rods d protruding from the disk b are accommodated, respectively.
The disk b is clamped between the rods d of the piston e from above and below so as to fix the rotation of the turntable.

[0003]

In the above-mentioned conventional fixing device, the torque T for fixing the rotation of the turntable is:
Piston diameter d = 6.3 cm, number of pistons N = 2
4. When the friction coefficient μ of the disc is 0.1, the pressure P in the cylinder is 70 kg / cm ² , and the diameter D of the circle on which the cylinders are arranged is D = 32 cm.

[0004]

(Equation 1)

[0005] That is, since the pressure receiving area of the piston e is small in spite of the large installation space, a large clamping force cannot be obtained. Further, if the clamping force is to be increased, the entire device becomes large and requires a large amount of space for installation. There was a problem. This invention has been made for the purpose of improving the above-mentioned conventional problems, and an object thereof is to provide a turntable fixing device capable of obtaining a larger clamping force without increasing the installation space.

[0006]

In order to achieve the above object, the present invention provides a clamp cylinder having ring-shaped pressure chambers above and below a disk fixed to a spindle which rotatably supports a turntable. A ring piston is accommodated in each pressure chamber of the clamp cylinder, and a plurality of rods for clamping the disk from above and below are provided on the surface of the disk of each ring piston.

[0007]

[Operation] Since the pressure receiving area of the piston for obtaining the clamping force can be increased by the above configuration, a larger clamping force can be obtained without increasing the size of the entire apparatus.

[0008]

An embodiment of the present invention will be described in detail with reference to the drawings shown in FIGS. FIG. 3 is a plan view of the fixing device, and FIG. 4 is a cross-sectional view thereof. In these figures, reference numeral 1 denotes a support shaft provided at the center of a turntable (not shown). The support shaft 1 is rotatably supported on a bed (not shown) of a machine tool by a bearing (not shown), and a disk 3 is fixed to a lower end of the support shaft 1 by a fixing tool 2. Reference numeral 4 denotes a ring-shaped clamp cylinder centered on the support shaft 1. A slit 4a is formed in the inner peripheral surface in the horizontal direction. The disk 3 is accommodated in the slit 4a, and the slit 4a A pressure chamber 4b is formed in a ring shape above and below, and a ring piston 4c is housed in these pressure chambers 4b so as to be vertically slidable.

On the inner and outer peripheral surfaces of the ring piston 4c, there are provided O-rings 5 which are in sliding contact with the inner and outer peripheral surfaces of the pressure chamber 4b.
For example, eight rods 4d are provided at equal intervals on the surface of the disk 3 so that they face each other. Each of the rods 4d has a columnar shape, and the disks 3 of the ring pistons 4c are fixed to the side surfaces by fixing members 6 as shown in FIG.
e is inserted slidably up and down with a small gap inside,
Movement in the radial direction is restricted. The disc 3 is clamped from above and below on the surfaces of the rods 4d facing each other to fix the rotation of the turntable.

Next, the operation of the fixing device constructed as described above will be described. When cutting or drilling a workpiece mounted on a turntable, the turntable is indexed and then the rotation is fixed by the fixing device. In this case, the hydraulic pressure P is supplied to each pressure chamber 4b of the clamp cylinder 4. As a result, the ring piston 4c accommodated in the pressure chamber 4a moves toward the disk 3, and the plurality of rods 4d fixed to each ring piston 4c clamp the disk 3 from above and below, thereby fixing the rotation of the turntable. . At this time, the torque for fixing the turntable is such that the outer diameter D ₁ of the ring piston 4c is 38 cm, the inner diameter D _{2 is} 26 cm, the friction coefficient μ of the disk 3 is 0.1, the oil pressure P is 70 kg / cm ² , and the rods 4d are arranged. Assuming that the diameter of the circle D is 32 cm,

[0011]

(Equation 2)

The torque of the conventional fixing device is 8.37.
1.61 times the bulging torque can be obtained for × 10 ⁴ kg · cm. When the pressure receiving area ratio of the conventional fixing device is S ₁ ,

[0013]

(Equation 3)

On the other hand, if the pressure receiving area of the above embodiment is S ₂ ,

[0015]

(Equation 4)

,

[0017]

(Equation 5)

## EQU1 ## Actually, n may not be an integer, and it is necessary to provide a gap between the cylinders, so that the pressure receiving area ratio is further increased.

[0019]

According to the present invention, as described in detail above, a larger clamping force can be obtained when the fixing device is formed in a size that can be installed in the same space as the conventional fixing device.
The turntable can be more securely fixed, and when the clamping force is the same as the conventional one, the size can be further reduced. Therefore, the turntable can be easily installed in a small space.

[Brief description of the drawings]

FIG. 1 is a plan view showing a conventional turntable fixing device.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a plan view showing a turntable fixing device according to an embodiment of the present invention.

FIG. 4 is a sectional view taken along line BB of FIG. 3;

FIG. 5 is an enlarged sectional view of a link piston.

[Explanation of symbols]

1 support shaft, 3 discs, 4 clamp cylinders, 4b
Pressure chamber, 4c ring piston, 4d rod.

Claims (1)

(57) [Scope of request for utility model registration] A clamp cylinder having ring-shaped pressure chambers is provided above and below a disk fixed to a support shaft rotatably supporting a turntable, and each pressure chamber of the clamp cylinder is provided. A turntable fixing device in which a ring piston 4c is accommodated in 4b and a plurality of rods 4d for clamping the disk 3 from above and below are protruded from the surface of the disk 3 of each ring piston 4c.