JPS62255042A - Clamping device - Google Patents

Abstract

PURPOSE:To enhance positioning accuracy and fix a clamp rigidly, by providing a plane surface portion for positioning axially radially and circumferentially, a taper portion and a taper hole for a fixed body, and fixing it rigidly with respective corresponding portions of a base. CONSTITUTION:The bottom surface of a pallet 5 is provided with a plane surface portion 5a for positioning axially, and a vertically movable pin 6 which is provided on a base 3 is inserted into a taper hole 5e which is provided at a central side, so that relative positioning is carried out. Furthermore, a projected portion 5b is provided for the central portion of the pallet, the neck portion of a pull stud 8 is gripped in balls 9 not to be extracted, the descent of a clamp rod which is slidable to the base 3 lowers the pallet 5 integrally, so that the taper portion 5c of the projected portion is fitted with the taper portion 14b of the clamp rod 10. Next, a piston 11 works so as to push up the taper portion 14b, so that the taper portion 5c of the pallet is fixed fast. Therefore, the pallet 5 can be fixed rigidly in radial, circumferential and axial directions.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a clamp device for positioning objects to be fixed, such as pallets and workpieces, in automatic machine tools such as machining centers.

Prior Art A conventionally known clamping device of this type is one in which a pallet is positioned with two pins relative to a base and is fixed by pressing it against the base side with a clamp piece. It will be done. In addition, with other clamp devices, the tip of the pull stand is inserted into the inside of the cylinder, and the pull stand is prevented from being removed by a locking body such as a ball that can move in the radial direction inside the cylinder. An example of this is a clamping mechanism for a tool shank for a machining center.

The former clamping device has the disadvantage that the clamping device itself is complicated and large-sized, and the pallet exchange device is also complicated. Moreover, the manufacturing cost of the pallet itself becomes high. Therefore, when considering pallets for small items, the above-mentioned pallets and clamping devices are inappropriate.

Furthermore, in the latter clamping device, since the allowable range of the shaft diameter of the tapered portion of the tool is large, the outer diameter cannot be made constant among a plurality of tools. For this reason,
Even if this clamping mechanism is incorporated into a pallet clamping device, the bottom surface of the pallet cannot be brought into close contact with the base surface, resulting in disadvantages in terms of rigidity and problems such as generation of vibration during cutting.

Purpose of the Invention Therefore, an object of the present invention is to be able to position objects to be fixed such as pallets with high accuracy in the axial, radial, and circumferential directions, to make the device itself more compact, and to reduce the manufacturing cost of objects to be fixed such as pallets. It is an object of the present invention to provide a clamping device which can be made inexpensive and also has strong locking properties.

SUMMARY OF THE INVENTION Therefore, the present invention is based on a pull stud type clamp mechanism, and uses this clamp mechanism to regulate the position of a pallet or the like in the axial direction on a reference surface, and then presses a tapered sleeve against a tapered surface on the pallet side. This allows the pallet to be accurately indexed in the radial direction of the shaft on the reference plane and fixed under a wedge action. Here, the holding operation of the pull stand and the driving operation of the tapered sleeve are achieved by differentially moving the two pistons based on the difference in pressure receiving area.

1 to 3 show a clamping device 1 of the present invention. This clamp device 1 is incorporated inside an index table 2, for example. The base 3 of the clamp device 1 has a hollow cylindrical shape, and the index table 2
It is rotatably supported via a bearing 4 inside.

On this base 3, a pallet 5, which is an object to be fixed, is arranged. This pallet 5 is formed in the following shape so that its position with respect to the base 3 is determined.

That is, the outer peripheral part of the bottom surface of the pallet 5 is provided with a flat surface part 5a for determining the position in the axial direction, and the outer peripheral surface of a substantially cylindrical protrusion part 5b that protrudes downward from the center part of the bottom surface of the pallet 5. A tapered portion 5c is provided for centering in the radial direction. Furthermore, this protrusion 5b
In this case, a straight cylindrical portion 5d for rough positioning is formed to further protrude in the radial direction above the tapered portion 5C. Further, in the bottom portion of the pallet 5, for example, one tapered hole 5e is formed closer to the center than the flat portion 5a in order to position the pallet 5 relative to the base 3. A taper pin 6 inserted into a pin hole a provided in the base 3 is fitted into the taper hole 5e. This taper pin 6 is movable in the vertical direction with respect to the base 3, and is pressed against the tapered hole 5e via a disc-shaped spring 7.

Further, a pull stand 8 is fixed to the protruding part 5b of the pallet 5 by screwing a threaded part 8a into the protruding part 5b. The distal end side of the pull stand 8 can be releasably connected to the clamp loft 10 via a ball 9.

This ball 9 is connected to the holding hole 1 at the tip of the clamp rod 10.
0e, it is fitted into the small hole 10a in the radial direction so that it can be taken in and out, and it moves against the cam surface 3d (.

The clamp rod 10 is arranged within the base 3 so as to be slidable in the vertical direction. The vertical movable range of the clamp rod 10 is determined by the contact between the end surface of the cylinder chamber 3C of the base 3 and the piston portion 10b.

Further, another piston 11 is fitted into the upper part of the clamp loft 10 so as to be slidable vertically within the shilling chamber 3e. The piston 11 and the piston portion 10b have opposing surfaces facing the hydraulic chamber 12 side, and the pressure receiving area of the piston 11 is formed to be smaller than the pressure receiving area of the piston portion 10b of the clamp rod 10.

Further, on the upper end side of the piston 11, a plurality of pins 13 are arranged in the circumferential direction. This pin 13 is provided so as to be able to slide into the small hole 3f of the base 3, and is configured to transmit the force of the piston 11 to the tapered sleeve 14. This tapered sleeve 14 can slide in the axial direction using the circular hole 3g of the base 30 as a guide, and the lower end flange portion 14 of this tapered sleeve 14
By the disc spring 15 provided between a and the base 3,
Taper sleeve 14 is always urged downward. This tapered sleeve 14 is configured such that its inner peripheral surface side tapered surface 14b is wedged into the tapered portion 5C of the pallet 5 within its movable range.

Note that a worm wheel 1 is provided on the outer periphery of the base 3.
6 is fixedly attached thereto, and this worm wheel 16 is engaged with a worm 17 on the index table 2 side. Further, a rotary joint 18 is rotatably attached to the lower end side of the clamp rod 10. Hydraulic ports 18a and 18b of this low rigidity joint 18 are annular groove portions that communicate with one of the hydraulic chamber 12 and the cylinder chamber 3C through passages 10c and 10d of the clamp rod 10. Furthermore, the air pressure port 18c is connected to the holding hole toe through the passage 10f of the clamp rod 10 at the annular groove portion, and further branches to communicate with the center hole 6a of the tapered pin 6 through the passage 3b of the base 3. .

Effect of the invention As shown in FIG. 1, when there is no pallet 5 on the base 3,
The clamp rod 10 receives hydraulic pressure from the hydraulic port 18b and is at its forward limit, and the tapered sleeve 14 is moved by the disc spring 15.
is pressed to the rearward limit. As a result, the ball 9 faces the large diameter portion of the cam surface 3d of the base 3.

In this state, when the pallet 5 is carried above the base 3 and placed on the base 3, the pull studs 8 push the balls 9 apart and enter the holding holes 10e of the clamp rods 10.

At this time, the pallet 5 has a tapered hole 5e and a tapered pin 6.
Due to the fit, relative positioning in the circumferential direction is achieved at this fit portion. At this point, the pallet 5 is still in an unclamped state, so the pallet 5 rotates around the taper pin 6, slides on the upper surface of the base 3, and is in a state where it can be accurately positioned during the subsequent clamping operation.

When transitioning from such an unclamped state to a clamped state, first open the hydraulic port 18a of the rotary joint 18.
Pressure is introduced into the hydraulic chamber 12 through the passage 10c.

At this time, the piston portion lOb first moves downward in the drawing, that is, in the retreating (clamping) direction, and as the clamp loft 10 moves, the ball 9 moves along the cam surface 3d of the base 3. Then, this ball 9 is moved toward the center by the small diameter portion of the cam surface 3d, and the pull stud 8
Since the pull stand 8 is prevented from being pulled out from the clamp rod 10 by pinching the neck of the pull stand 8, the pull stand 8 will move downward integrally following the downward movement of the clamp rod 10. Until the flat part 5a of the pallet 5 comes into contact with the base 3 as shown in FIG. It has become. At this time, the piston 11 tries to push the tapered sleeve 14 upward, that is, in the forward direction, through the pin 13 due to the pressure, but the elastic force of the disc spring 15 is stronger than the pressure value of the hydraulic chamber 12. Therefore, the tapered sleeve 14 is still pressed to the retraction limit position. In this way, the pallet 5 is in contact with the mounting surface of the base 3 as a reference surface and is positioned in the axial direction of the clamp rod 10.

After the flat portion 5a of the pallet 5 comes into contact with the base 3, the pressure in the hydraulic chamber 12 increases to the supply pressure. The force with which the piston 11 tries to push the tapered sleeve 14 forward against the disc spring 15 due to this supply pressure is
The elastic force is set to be sufficiently larger than the elastic force of No. 5. Therefore, in the process of being pushed upward, the tapered sleeve 14 touches the pallet 5 with the tapered surface 14b, as shown in FIG.
The tapered portion 5C of the tapered portion 5C is pressed into close contact. At this time,
The tapered sleeve 14 acts like a wedge between the circular hole 3g and the tapered portion 5C. by this,
The pallet 5 is accurately centered by the tapered portion 5C,
At the same time, it will be securely clamped. In addition, during this time, since the piston part 10b has a larger pressure receiving area than the piston 11, the pallet 5 is moved due to the differential force.
It is pressed against base 3.

In this way, the pallet 5 is accurately positioned relative to the base 3 and is clamped with a strong force.

In this state, the workpiece fixed to the pallet 5 is subjected to necessary machining. In this machining process, when the worm 17 is rotated by a predetermined amount, the base 3 rotates relative to the index table 2 while keeping the pallet 5 in a clamped state, thereby indexing the pallet 5 at a desired angle. go. During this rotational indexing, the rotary joint 18 remains stationary and allows the clamp rod 10 to rotate, thereby maintaining the necessary pressure from the piping system.

After machining, when transitioning from the clamped state to the unclamped state, press the hydraulic port 1 of the low clamp joint 18.
Pressure is applied from 8b to the rear end side chamber of the cylinder chamber 3c. Then, the clamp rod 10 moves upward, and at the same time the ball 9 also faces the large diameter part of the cam surface 3d, so the pull stud 8 is released from the locked state with respect to the clamp loft 10, so that the pallet 5 is in an unclamped state. Note that the air pressure port 18c is located in the pin hole 3a of the base 3.
s and the holding hole 10e at the upper end of the clamp rod 10, and by sending air pressure through the air pressure port 18c, chips and the like in the tapered hole 5e and the holding hole 10e are blown away.

Other Embodiments In the embodiments described above, the pull stand 8 is configured to be releasably engaged with the clamp rod 10 via the ball 9, but the invention is not limited to this. For example, the pull stand 8 is clamped. It may be constructed so that it can be releasably engaged with a locking body such as a collet provided on the upper end side of the loft 10.

Further, in the above-described embodiments, a pallet on which a work is placed is used as an example of the object to be fixed, but the object to be fixed may be the work itself. Furthermore, clamp rod 1
0 may be installed not in the vertical direction but in the horizontal direction or at an appropriate inclination angle.

Effects of the Invention The present invention provides the following effects. An object to be fixed such as a pallet has a flat part for determining the axial direction, a tapered part for centering in the radial direction, and a tapered hole for determining the circumferential direction. Highly accurate positioning is possible in the direction and circumferential direction. Further, although the clamping mechanism is based on a tapered portion, the bottom surface of the object to be fixed can also be firmly fixed to the base with the tapered sleeve, resulting in a highly rigid clamped state. Furthermore, since the piston mechanism is used to sequentially perform the removal, stopping, and centering operations, there is no loss in operating time, and since there is only one operating circuit, the circuit configuration can be simplified.

In addition, since the mechanism is simple, the device itself can be made compact and the manufacturing cost can be reduced. Furthermore, since the shape of the object to be fixed can be simplified, the manufacturing cost can also be reduced.

[Brief explanation of drawings]

1 to 3 are cross-sectional views showing various operating states of the clamp device according to the present invention. 1... Clamp device, 3... Base, 3c... Cylinder chamber, 5... Pallet, 5a... Flat part, 5c,... Taper part, 5e... Tapered hole, 6... Taper pin, 8...
Pull stud, 10...clamp rod, 10b...piston part, 11...piston, 14...taper sleeve, 14b...tapered surface, work 5...disc spring.

Claims (1)

[Claims] 1) A base having circumferential positioning pins erected thereon, a positioning hole provided at a position corresponding to the positioning pin of this base, and a positioning hole provided at a predetermined position on the bottom part. The object to be fixed has a flat part for axial positioning and a protruding part protruding from the center of the bottom surface, and a tapered part for centering in the radial direction is formed on the outer circumferential surface of the fixed object. A pull stud fixed to a protruding part of an object, a clamp rod forming a piston part in a cylinder chamber of the base, slidably disposed by the piston part, and capable of engaging with a tip of the pull stud, and the clamp. A piston is slidably fitted into the rod and has a smaller pressure-receiving area than the piston portion, and the piston is placed above the piston and is always urged in the backward direction by a spring, and the fixed object is moved by the forward movement of the piston. 1. A clamping device comprising: a tapered sleeve having a tapered surface that tightly holds a tapered portion of the clamping device. (2) The clamp device according to claim 1, wherein the object to be fixed is a pallet. (3) The clamp device according to claim 1, wherein the object to be fixed is a workpiece. (4) The clamp device according to claim 1, 2, or 3, wherein the base is supported so as to be indexable about the clamp rod as a rotation center.