JPH029513A - Mounting and demounting method for main shaft tool - Google Patents

Abstract

PURPOSE:To obtain a strong tool clamping force and shorten tool mounting and demounting time by having both the first and the second springs work while cutting is ongoing and opening a collet when a tool exchange command is issued, by keeping only the second spring in a state of non-working before a tool is pulled out, and keeping the first spring in a state of non-working while the second spring is in non- working condition when the tool is being pulled out. CONSTITUTION:While cutting is ongoing, the first disc spring 6 for retracting and holding a tool and the second disc spring 12 for reinforcing retractive force are made to work. When a tool exchange command is issued, the second disc spring force is removed before the tool is pulled out, and when the tool is being pulled out, the first disc spring force is removed in the said condition to open a collect which is holding the tool. As the result, tool clamping force is intensified to prevent an inserted tool from getting loose. Furthermore, when a tool exchange command is issued, the force of the second disc spring 12 is made not to work on a pulling rod 3, so that the inconvenience of increased time for unclamping is eliminated. Furthermore, the arrangement allows a high speed operation of pistons, 14 and 17, with less amount of oil, hence the tool exchange time can be furtherly shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for attaching and detaching a spindle tool to a machine tool, particularly a machining center, a boring machine, a radial drilling machine, etc.

Conventional technology Conventionally, tools that are attached to the tip of the spindle are held in place by gripping the pull stand at the tip of the shank with a collet and pulling it with a tension rod biased by dozens of disc springs. . Also, a method is used in which a tapped hole is provided at the tip of the tool shank, a screw of a pull rod is screwed into the tool shank, and the tool is firmly tightened and fitted.

Problems to be Solved by the Invention In the former case, when large cutting forces are applied, such as in the case of mold machining, the conventionally commonly used methods do not provide sufficient clamping force, resulting in loosening during work. There was a problem that accurate processing was not possible. Additionally, if the spring is made stronger, a larger force is required to release it, and the diameter of the cylinder that pushes the pull rod becomes larger, requiring a larger amount of oil. Further, in the case where a force increasing mechanism is provided, the length of the cylinder becomes long and a large amount of oil is required, making it difficult to tighten and release tools at high speed.

In the latter method, the tightening force is strong, but there is a problem in that it takes time to turn the threaded rod and the tool change time is prolonged.

Therefore, the present invention was developed in view of the problems of the present invention and the prior art, and its purpose is to provide a method for attaching and detaching a spindle tool that provides strong tool tightening force and does not prolong the tool attachment and detachment time. This is what we are trying to provide.

Means for Solving the Problems In order to achieve the above-mentioned objects, the present invention provides a method for attaching and detaching a spindle tool by applying and deactivating a spring force acting on a pull rod that retracts a collet that grips the tool. A first spring that pulls in and holds the tool and a second spring that strengthens the retraction force are both activated, and when a tool change command is issued, only the second spring is deactivated before the tool is removed, and when the tool is removed, the second spring is activated. The collet is opened by making the first spring inactive in a state where no force is applied.

Example Embodiments of the present invention will be described below based on the drawings.

A main shaft 2 rotatably supported by a main shaft sleeve 1 has a hole in the center through which a tension rod 3 passes, and a taper hole in which a taper shank 4 of a tool is mounted at the tip. At the tip of the pull rod 3 is a pull stand 4a at the tip of the tool shank 4.
A well-known collet 5 mechanism that locks with the collet 5 is provided,
Several dozen laminated first plate springs 6 are interposed between the central flange 3a and the long leg 2a of the main shaft 2, and are always biased in the direction of pulling the tool. Further, a stopper 7 having a tapered surface 7a with a large angle formed by an inclined surface pushing the ball 8 in the radial direction is screwed onto the inner end of the tension rod 3 and fixed with a nand. A retainer 9 in the shape of a storage cup that holds a plurality of balls 8 so that they can move in the radial direction on the same circumference and do not fall off is fitted on the tension rod 3, and the end surface of the stopper in contact with the balls 8 is attached to the handle 9a. Tapered surface 7
A sleeve 10 having a female tapered surface 10a that is more acute than the angle a is fitted. The end surface 10b of the sleeve 10 is pressed toward the stopper 7 side by dozens of second disc springs 12 interposed between the end face 10b of the sleeve 10 and the washer that is stopped by the stride 2b of the main shaft 2 through the backing plate 11. and tapered surface 10a
are constantly in contact with each other via the ball 8 and are biased to pull the tension rod 3 in addition to the force of the first disc spring 6. A second cylinder tube 13 is fixedly installed on the end face of the main shaft sleeve l, in the same position as the main shaft 2, and a tension rod 3. A hollow second piston 14 having a hole diameter that does not interfere with the stopper 7 and the retainer 9 is fitted, and when pressure oil is sent from the pressure oil port 15 that opens into the oil chamber 13a, the piston 14 moves to the right in the figure. The end face 14b presses the end face of the sleeve 10 and compresses the second disk spring 12 so that it does not act on the tension rod 3. The second cylinder tube 13 has a first cylinder which is longer than the second cylinder tube.
A cylinder tube 16 is fixedly installed, and a first piston I7 is fitted into this cylinder. A push rod 18 is integrally attached to the center of the first piston 17, and one side passes through the end wall of the second cylinder tube 13 and the second piston 14, and the second piston 14 is extended at the flange 18a at the end of the push rod. The gap between the end surface of the collar engaged with 14a and the end surface of the shaft of the tension rod 3 is configured to be larger than the gap between the end surface of the second piston 14 and the end surface of the sleeve IO. A dog 19 is attached to the other end. Inside the cylinder of the first cylinder tube 16, a pullback spring 20 is interposed between the first piston 17 and the end wall of the second cylinder tube 13, and urges the first piston 17 to the left in the figure. Possibly push rod 18
The collar portion pulls the second piston 14 back to the left end. 1st
Pressure oil ports 21 and 22 are opened in the oil chamber of the cylinder cylinder 16, respectively, and are connected to the pressure oil side and the discharge side. A switch mounting tube 2 is provided on the end surface of the first cylinder tube 16.
3 is fixedly installed, and limit switches LSI and LS2 are mounted opposite the dog 19 of the push rod 18 protruding from the center.
．． LS3 is attached, and the limit switch LSI is attached to the first disc spring 6. in accordance with the axial position of the push rod. When the second disc spring 12 is acting, the limit switch L
When only the first disc spring 6 is acting, the limit switch LS3 is activated by the first disc spring 6.S2. Both the second disc spring 12 does not work and a confirmation signal indicating that the tool is loose is output.

Next, the action will be explained. Pressure oil is sent to the pressure oil ports 15 and 22, and the second piston 14 moves to the right and presses the sleeve 10, compressing the second disc spring 12 via the receiving plate 11, and the spring force is applied to the tension rod 3. The first piston 17 is moved to the right, and the push rod 18 pushes the tension rod 3 against the spring force of the first disc spring 6, so that the collet 5 is opened and the limit switch LS3 is turned on. A confirmation signal for fully loosening is output. In this state, when the tool shank 4 is attached to the hole of the spindle 2 by an automatic tool changer (not shown), the pressure oil is sent to the pressure oil port 21, and the pressure oil ports 22 and 15 are connected to the discharge side. . Therefore, the first piston 17 moves both the push rod 18 and the second piston 14 to the left, and the pull rod 3. To release the pressure on the sleeve lO, there is a first
The spring force of the disc spring 6 acts on the flange 3a, and the force of the second disc spring 12 acts on the sleeve 10 via the receiving plate 11, causing the female tapered surface 10a of the stopper 7 fixed to the tension rod 3 via the ball 8. A double force acts on the tapered surface 7a, moves the pull rod 3 to the left, closes the collet 5, grips the pull stud 4a of the tool shank 4, and acts to pull it in, crimping the tapered surfaces together and moving the tool onto the spindle 2. Attach with strong force. Dog 19 turns on the limit switch LSI and clamps everything! i1m A recognition signal is issued. Upon receiving this signal, the spindle moves to the machining position and begins machining. When a large cutting force is applied, such as when machining a mold, the tool receives a force in the direction of loosening.When the tension rod 3 is pulled, the slanted surface of the large-angle tapered surface 7a of the stopper 7 at the end of the shaft causes the tool to loosen slightly in the axial direction. As the ball 8 is pushed outward in the radial direction, the inner slope of the acute female tapered surface 10a of the sleeve 10 expands and moves the sleeve in the direction of the disc spring, compressing the second disc spring 12 and causing the spring to spring out. Increases force and automatically prevents tools from loosening.

Is there a restriction when a tool change is specified? The second piston member, which can be operated by the J device during non-cutting, is activated by the pressure oil port 1 of the second cylinder cylinder 13 while the main shaft sleeve 1 is moving to the replacement position, for example.
5, the second piston 14 moves to the right and pushes the end surface of the sleeve 10.

The sleeve 10 slides on the retainer 9 and compresses the second disc spring 12, cutting the edge so that the force does not act on the tapered surface 7a of the stopper 7.

At this time, the push rod 18 is also moved to the right along with the second piston 14 against the force of the spring 20, but the end face of the collar 18a does not come into contact with the tension rod 3. Grip the tool with just one hand. When the main shaft 2 is positioned in response to a tool exchange command and a tool exchange arm (not shown) grips a tool, the pressure oil port 21 of the first cylinder cylinder 16 is connected to the discharge side, and when pressure oil is sent to the pressure oil port 22, the first piston 17
:! , the push rod 18 and the second
The sliding portion with the piston 14 slides, and only the push rod 18 is pushed to the right to push the shaft end of the tension rod 3, thereby causing the first disc spring 6 to
is compressed, the collet 5 is released, the pull stand 4a of the shank 4 is released, and the tool exchange arm can pull out the tool.

Second piston 14. Even when the hydraulic pressure that moves the first piston 17 to the left decreases, the spring 20 biases the first piston 17 to the left, so the second piston 14 engaged with the push rod 18 t of the second piston end 14a and the push rod 18 also maintains the left row end position:! l 18 a is the sleeve 10. Since it does not come into contact with the tension rod 3, no interference occurs when the main shaft 2 rotates.

In this embodiment, the force increasing mechanism is created by selecting the angle between the stopper 7 tapered surface 7a and the sleeve female tapered surface 10a, but this is not necessarily necessary and the purpose can be achieved if the second disk spring 12 is strong.

Effects As detailed above, the present invention applies the first spring for holding the tool retraction and the second spring for reinforcing the retraction force during cutting, and when a tool change command is issued, removes the second spring force before removing the tool. When removing the tool, the first spring force is removed and the collet gripping the tool is released in this state, so the tightening force of the tool is strong, and even for heavy-duty cutting and heavy-duty tools, there is no loosening of the fitted tool. can be prevented. Also, the tool exchange fingers.

Since the force of the second disc spring does not act on the tension bar when the command is issued, the inconvenience of an increase in the time for tightening and releasing does not occur, and the strength of the first disc spring is the minimum required to hold the tool. The force of the pressure oil pushing the first piston is reduced, the amount of oil is reduced, and the piston can be moved at high speed. Strong tightening provides force while further shortening tool change time. It has the characteristics of being able to

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a tool gripping portion, and FIG. 2 is a longitudinal sectional view of a cylinder portion and a force increasing mechanism portion for releasing the tool holding force. 2. Main shaft 3. Tension rod 5. Collet 6. First disc spring 7. Stopper 8. Ball 10. Sleeve 12. Second disc spring 13. Second.
Cylinder tube 14.17... Piston 18... Push rod 16... 1st
cylinder tube

Claims (1)

[Claims] (1) In a method of attaching and detaching a spindle tool by applying and inactivating a spring force acting on a pull rod that pulls in a collet that grips the tool, during cutting, the first spring that pulls in and holds the tool and the second spring that strengthens the pulling force are used. When a tool change command is issued, only the second spring is made inactive before the tool is removed, and when the tool is removed, the first spring is made inactive while the force of the second spring is not applied. A method for attaching and detaching a spindle tool, characterized in that the collet is opened by: