JPH01146602A - Tool mounting/demounting device - Google Patents

Abstract

PURPOSE:To improve the concentricity of a resilient body with a main spindle to improve balance, by a method wherein an axially sliding pusher is situated inside a draw bar, a pusher is moved forward during unfolding, and the rear end of the draw bar is released from engagement with the resilient body. CONSTITUTION:A cap 32 is pushed forward, a resilient body 24 is pressed, a pusher 16 is pushed to move a groove part 22, and a collet 14 is inclined inwardly to release engagement with the resilient body 24. A large part 20 is engaged with the stepped part of a draw bar 8 to forcibly move forward the draw bar 8, and a chuck 12 is unfolded. When a tool 100 is inserted and the press force of the pusher 16 is gradually released, the draw bar 8 is moved backward through the force of a spring 36, and a chuck 10 grasps a pull stud 102. Further, when the pusher 16 is moved backward, the large part 20 forcibly unfolds the collet 14 to engage the collect 14 with the resilient body 24. When the press of the cap 32 is rendered ineffective, a clamp 28 is moved backward, and the resilient body 24 is expanded. Since the collet 14 is pulled backward and the draw bar 8 is moved backward, a tool 100 gripped by the chuck 10 is pulled in for firm grip.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Applications> The present invention relates to a tool attachment/detachment device in which the elastic body of the chuck is installed so as not to play, thereby improving rotation accuracy.

<Prior Art> A conventional tool attachment/detachment device is shown in FIG. The figure shows attachment/detachment device 5.
0, the upper half of the center line a-ail shows the tool 100 in a clamped state, and the lower half shows the unclamped state.

This attachment/detachment device 50 has a tapered insertion hole 54 in front of a main shaft 52 (left side in the figure) which is the main body of the outer frame, and the tool 100 is inserted through this insertion hole 54 . Main shaft 52
has a cylindrical shape, and a cylindrical drawbar 56 is provided inside to be slidable in the axial direction. A chuck 58 divided into several parts in the circumferential direction is fixed to the front of the drawbar 56 and moves together with the drawbar 56. chuck 58
The front end of the tool pull stud chuck 60 is enlarged.
It becomes. This tool pull stud chuck 60 is
When it moves backward, it comes into contact with the sleeve 62 fixed to the main shaft 52 and is bent inward, causing the pull stud 10 of the tool 100 to
It is designed to hold 2. Drawbar 56 and main shaft 5
2, a plurality of disc springs 64 are installed over the length L. The front side of this disc spring 64 is the sleeve 6
2, and the other end, that is, the rear end, is locked to a locking portion 66 fixed to the drawbar 56.

When the rear end of the drawbar 56 is pushed forward with a force, the tool pull stud chuck 60 protrudes from the sleeve 62 and the chuck 58 is opened and expanded. Accordingly, the disc spring 64 is compressed from the length Ll to L2, and the amount of contraction δ=
L, −L2 elastic force is generated. When the tool 100 is inserted into the insertion hole 54 and the pressure on the drawbar 56 is released, the drawbar 56 is pulled back by the elastic force of the disc spring 64.
Similarly, the pull stud 102 of the tool 100 is gripped by the tool pull stud chuck 60 and the disc spring 64
The tool 10 is further pulled backward by the elastic force of
0 will now be held.

<Problems to be Solved by the Invention> In the conventional tool attachment/detachment device 50, since the tool 100 is gripped by the elastic force of the disc spring 64 as described above, the problem caused by the compression of the disc spring 64 A gap is provided in advance between the disc spring 64, the main shaft 52, and the drawbar 56 to accommodate changes in length in the radial direction. Therefore, these disc springs 64 are slightly eccentric within the main shaft 52 with respect to the center of rotation of the main shaft 52. On the other hand, in recent years, there has been a need to increase the rotational speed of the main shaft 52 to an extremely high speed in order to improve efficiency and the like. In order to achieve this ultra-high speed, the eccentricity of the disc spring 64 causes vibrations due to unbalanced mass, which significantly deteriorates the accuracy of the main shaft 52 and significantly reduces machining accuracy, such as the roundness and surface roughness of the workpiece. let

In addition, in the tool attaching/detaching device 50, in order to grip the tool 100 with sufficient force, the disc spring 64 is placed under considerable compression during clamping, and is further compressed when unclamping to release the tool 100. Because of the configuration, the conditions required for the elastic body are high, and conventional elastic bodies have not been found suitable to replace the disc spring 64, and a decrease in accuracy due to eccentricity of the disc spring 64 has become unavoidable.

Means for Solving the Problems> In order to solve the above problems, the present invention configures a tool attachment/detachment device as follows. That is, a pull stud chuck is attached to the tip of the drawbar, and a tool attachment/detachment device is installed between the outer frame body and the drawbar to open and close the pull stud chuck and attach/detach a tool by operating the drawbar in the axial direction. an elastic body is provided in the drawbar, a pusher that is slidable in the axial direction with respect to the main body and the drawbar is inserted inside the drawbar, and a collet that engages with the elastic body when opened and expanded is formed at the rear end of the drawbar. , the pusher is provided with a relief portion that allows the collet to converge inward so that the pusher is disengaged from the elastic body when the pusher is moved toward the tip of the drawbar, and the elastic body is pressed in the axial direction. It was constructed by providing a clamper to make it possible.

When the pusher is pushed in, the groove (relief) reaches the position of the collet, the collet is removed from the elastic body, the drawbar moves forward, and the chuck releases its grip on the tool. When installing a tool, the pusher is gradually retreated (then the chuck grips the tool, and the collet engages the elastic body. Then, by releasing the compression of the elastic body, the chuck is pulled backward and the tool is removed). grip firmly.

Embodiment> An embodiment of the tool attachment/detachment device according to the present invention will be described. FIG. 1 shows a cross section of the tool attaching/detaching device 2, in which the upper half along the center line a-a shows when the tool 100 is clamped, and the lower half shows when the tool 100 is unclamped, as in the conventional example.

The main shaft 4 has a cylindrical shape, and a tool 10 is attached to its tip (left side in the figure).
A tapered insertion hole 6 into which a 0 is inserted is formed. A drawbar 8 is provided inside the main shaft 2. The drawbar 8 is slidable in the axial direction with respect to the main shaft 2, and has a chuck 10 fixed to the front thereof. The tip of the chuck 10 is divided into several parts, and the end is enlarged to form a pull stud chuck 12. When the pull stud chuck 12 moves rearward, it enters inside a sleeve 11 fixed to the inner periphery of the main shaft 4 and closes.

The rear part of the drawbar 8 is divided into several parts like the tip part,
It is formed as an outwardly projecting collet 14. A pusher 16 is slidably inserted inside the collet 14. The pusher 16 has different diameters at the front and the middle, and the small diameter part 18 at the front just fits inside the drawbar 8, and the large diameter part 20 at the middle just fits into the inside diameter of the collet 14. ing. Larger diameter portion 20
A groove 22 into which the collet 14 falls inward is formed at the rear. An elastic body 24 is disposed between the collet 14 and the main shaft 4, the front end of this elastic body 24 is fixed to the main shaft 4 side by a locking ring 26, and the rear end side is a free end and the collet 14. A ramper 28 is provided on the free end side of the elastic body 24, facing the free end and movable in the axial direction. A cap 32 having a hole 30 is attached to the rear end of the clamper 28 .

Further, a spring 34 whose tip is engaged with the drawbar 8 is attached to the front of the pusher 20, and a spring 36 whose tip is engaged with the sleeve 11 is further attached to the middle outer circumference of the drawbar 8. It is.

Next, the operation of the tool attachment/detachment device 2 will be described. First, the cap 32 is pushed forward and the elastic body 24 is pressed. The pusher 16 is pushed through the hole 30 of the cap 32, the groove 22 is moved to the collet 14, the collet 14 is tilted inward, and the engagement with the elastic body 24 is released. At the same time, the large-diameter portion 20 of the pusher 16 engages with the stepped portion of the drawbar 8 and pushes the drawbar 8 forward.
Expand 2. Such a state is a-a in FIG.
This is the lower half of the line, which is also the lower half in FIG. From this state, the tool 100 is inserted through the insertion hole 6 and the pressing force of the pusher 16 is gradually released. Then, the lever 8 moves back under the action of the spring 36, and the chuck 10 grips the pull stud 102 of the tool 100.

When the pusher 16 further retreats, the large-diameter portion 20 pushes the collet 14 from the inside and spreads it out, causing the collet 14 to engage with the elastic body 24. When the pressure on the cap 32 is released, the clamp 28 retreats and the elastic body 24 expands. Elastic body 24
The extension of the tool 100 held by the chuck 10 pulls the collet 14 backward and moves the drawbar 8 backward.
Pull it inside and grip it firmly.

Therefore, in the tool attaching/detaching device 2, there is no need to press the elastic body 24 holding the tool 100 more strongly when unclamping the tool 100 than when clamping it. Therefore, by using something other than a disc spring for the elastic body 24, the clearance between the elastic body 24, the main shaft 4, and the drawbar 8 can be set to the minimum, and the rotation accuracy of the main shaft 4 can be improved. .

FIG. 3 shows an example of an elastic body. This elastic body 24a is composed of a bead portion 40 and sliding portions 42, 44, and the bead portion 40 is adapted to expand and contract as appropriate due to the pressing force in the axial direction, and therefore has a diameter. It has some clearance with respect to the inner diameter of the main shaft 4. The supporting parts 42 and 44 do not deform due to compressive force in the axial direction, and their diameters have a minimum clearance to the inner diameter of the main shaft 4, that is, a clearance such that they can move within the main shaft 4 by the elastic force of the bellows part 40. It becomes. Therefore, it can be arranged concentrically with the main shaft 4 within the main shaft 4, and the eccentricity of the elastic body 24a can be minimized.Furthermore, another embodiment of the elastic member 24 is shown in FIG. The elastic body 24b consists of a deformable portion 47 formed by cutting slits 46 in a staggered manner on the outer periphery of a cylinder, and support portions 48 and 49 that do not deform, and the elastic body may be configured in this way.

Note that the elastic body of the present invention is not limited to the above two examples.

<Effects of the Invention> In the present invention, a tool attachment/detachment device is provided in which a pull stud chuck is attached to the tip of a drawbar, and the pull stud chuck is opened/closed by operating the drawbar in the axial direction to attach/detach a tool. and the drawbar, a pusher that is slidable in the axial direction with respect to the main body and the drawbar is pushed into the inside of the drawbar, and a collet that engages with the elastic body during expansion and expansion is inserted into the drawbar. a relief portion formed at the rear end of the pusher so that the collet can converge inward so that engagement with the elastic body is released when the pusher is moved toward the distal end of the drawbar; Since the structure is equipped with a clamper that presses the elastic body in the axial direction, the concentricity of the elastic body with respect to the main axis can be greatly increased, eliminating unbalance of the stationary mold and preventing vibration of the main axis even when rotating at high speed. As a result, a highly accurate, high-speed spindle with small runout at the spindle end can be realized.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the tool attaching/detaching device according to the present invention, FIG. 2 is a sectional view taken along A-A R in FIG. The figure is a sectional view of a conventional example. In the drawing, 2.50 is a tool attaching/detaching device, 4.52 is a main shaft, 8.56 is a drawbar 1, 10.58 is a chuck, 14 is a collet, 16 is a pusher, 22 is a groove, 24.24a, 24b are elastic bodies , 28 is a clamper, and 100 is a tool. Patent applicant Mitsubishi Heavy Industries, Ltd. Agent

Claims (1)

[Claims] In the tool attachment/detachment device, a pull stud chuck is attached to the tip of a drawbar, and the pull stud chuck is opened/closed by operating the drawbar in the axial direction to attach/detach the tool. a pusher that is slidable in the axial direction with respect to the main body and the drawbar is inserted inside the drawbar, a collet that engages with the elastic body during expansion and expansion is formed at the rear end of the drawbar; The pusher is provided with a relief portion that allows the collet to converge inward so that engagement with the elastic body is released when the pusher is moved toward the tip of the drawbar, and a clamper that presses the elastic body in the axial direction. A tool attachment/detachment device characterized by being provided with.