JP2590563Y2 - Tool attachment / detachment 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 tool attachment / detachment device mounted in a main shaft of a machine tool.

[0002]

2. Description of the Related Art In a machine tool having an automatic tool changing device, a tool attaching / detaching device for automatically tightening and holding a tool mounted in a spindle is generally used.
In a tool attachment / detachment device, it is required to firmly and automatically tighten a tool mounted in a spindle in order to improve the performance of a machine tool and cope with a wide range of machining.

[0003] In accordance with such demands, generally, in a tool attaching / detaching device, a tightening force is secured by directly pulling a draw bar inserted into a main shaft and holding a tool only by a spring force. However, an attempt to increase the biasing force of the spring force in order to increase the tightening force of the tool involves a dimensional increase. Further, as another means for enhancing the tightening force, there is a tool gripping member for gripping a tool, and a booster mechanism or a lock mechanism at the rear end of the drawbar.

[0004] As a tool attachment / detachment device employing such a booster mechanism, for example, the one disclosed in Japanese Utility Model Laid-Open No. 2-104906 is known. In this tool attachment / detachment device, a pull-in bar for tightening a tool by a front end claw is inserted into a main shaft, and a tapered sleeve having a wedge surface is fixedly provided at a rear end of the pull-in bar. ,
It is always urged rearward by a spring material. A sphere is disposed between the wedge surface of the tapered sleeve and the inclined surface formed on the inner wall surface of the main shaft. When the tool is tightened, the spring force of the spring material is transmitted to the pull-in bar via the tapered sleeve and the sphere. And the retraction bar is balanced with the pull bar pulled rearward.

When a pulling force acts on the tool, the pulling force is transmitted to the sphere via a pressing member provided on the drawing bar, and is formed on the wedge surface of the tapered sleeve and the inner wall surface of the main shaft through the sphere. The load is shared by the inclined surface and the load on the spring material is reduced by the wedge surface.

[0006]

However, in the conventional tool attachment / detachment device, when the tool is tightened or when the tool is switched from the unfastened state, the pressing member is displaced in the axial direction and the radial direction so that the sphere is displaced. There is a problem that the booster mechanism is complicated because it needs to be moved.

Further, since the pull-in bar is a transmission path of the pull-out force and the spring material is interposed between the hook of the pull-in bar and the tapered sleeve, the pull-out force is transmitted from the hook at the transmission point of the tool pull-out force. The dimension up to the wedge surface of the tapered sleeve at the point of transmission is increased. Therefore, for example, the drawing bar is extended by the drawing force, the drawing force acting on the drawing bar is absorbed in the middle, and it becomes difficult to reliably transmit the drawing force to the wedge surface of the draw bar, and it is possible to securely tighten the tool. There was a problem that it was not possible.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the invention is to securely tighten a tool with a simple structure without increasing the size and complexity of the apparatus and to tighten the tool. An object of the present invention is to provide a tool attachment / detachment device capable of increasing a force.

[0009]

SUMMARY OF THE INVENTION According to the present invention, there is provided a spindle having an insertion hole through which a tool is attached and detached, an inner peripheral wall of the insertion hole having an inner peripheral inclined surface expanding in diameter rearward, and a spindle. A contact portion that is movably inserted into the insertion hole portion, and protrudes outward, and an annular groove portion that is located behind the contact portion and has a front groove wall surface with a wedge surface that is reduced in diameter rearward. A draw bar and an insertion hole, which are disposed on the outer periphery of the draw bar so as to be movable in the axial direction for a predetermined distance, to tighten the tool when closed and to release the tool when opened. Such a claw is provided at the front end, a plurality of holes are provided along the circumferential direction at the rear end, and at a position separated by a predetermined gap from a contact portion of the draw bar when tightening the tool. When the tool is released, the stopper that moves and contacts the contact part of the drawbar The tool gripping member formed in the above, provided in each hole at the rear end of the tool gripping member, and at the time of tightening the tool, on the wedge surface of the annular groove of the draw bar and the inner peripheral inclined surface of the insertion hole of the main shaft. A sphere that abuts and is loosely supported in the annular groove at the time of tool release, and a fixed projection fixed to the inner peripheral wall in the insertion hole of the main shaft at a position behind the inner peripheral inclined surface of the insertion hole. And a spring receiver fixed to the rear end of the drawbar, and mounted between a fixed protrusion in the insertion hole of the main shaft and a spring receiver at the rear end of the drawbar, and constantly urges the drawbar rearward. It is characterized by comprising a spring material and a pusher that does not press the drawbar forward when the tool is tightened and presses the drawbar forward against the urging force of the spring material when the tool is released.

[0010]

According to the present invention, when the push of the draw bar by the pusher is released, the urging force of the spring material causes
The tool is tightened by the claws of the tool gripping member.

In a state where the draw bar is pressed against the urging force of the spring material by the pusher, the tightening of the tool by the claws of the tool holding member is released. That is, when the tool mounted on the spindle is tightened and fixed, the pressing of the drawbar by the pusher is released. As a result, the draw bar is retracted by the urging force of the spring material, and the tool gripping member is also retracted via the sphere with this, whereby the claw of the tool gripping member is closed and the tool is tightened by the claw. The retraction of the tool holding member is stopped by the tool, and the tool holding member is balanced with the biasing force of the spring material. At this time, the sphere moves in the outer diameter direction and abuts against the inner peripheral inclined surface of the insertion hole. In this state, the drawbar is further pulled rearward by the spring material. And pressed. In this state, the sphere is balanced in three-point contact with the wedge surface of the draw bar, the inner peripheral inclined surface of the insertion hole, and the wall surface of the hole of the tool gripping member. Therefore, the wedge surface of the drawbar and the insertion of the spindle
The contact between the three points of the inner peripheral slope of the inlet and the hole of the tool gripping member
The tool gripping member is closed by touch to tighten the tool,
Without increasing the urging force of the spring material, the tool
Increase.

When a pulling force (a force for pulling the tool forward) acts on the tool, the tool gripping member and the drawbar are integrated via the sphere, so that the pulling force is transmitted to the sphere via the tool gripping member. Then, the sphere is pressed forward by the hole of the tool gripping member, and the pulling force transmitted to the sphere is borne by the wedge surface of the draw bar and the inner peripheral inclined surface of the insertion hole.

A pressing force perpendicular to the wedge surface is transmitted to the wedge surface of the draw bar by a sphere, but an axial component of the pressing force acts in the axial direction of the draw bar . tool
The pull-out force is determined by the biasing force of the spring material and the inner circumference of the insertion hole of the spindle.
It balances with the sum of the reaction force that the inclined surface gives to the sphere.

When the tool is removed from the main shaft, when the tool is switched from the tightened state to the tool released state, the drawbar is pressed against the urging force of the spring material by the pusher. As a result, the drawbar advances while the tool gripping member is stopped, and the sphere falls into the annular groove of the drawbar toward the radial center direction. When the draw bar advances by a predetermined distance (gap), it comes into contact with the stopper portion of the tool gripping member, the tool gripping member is moved forward with the advance of the draw bar, and the tool tightening by the claw of the tool gripping member is released.

[0015]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 to 4 show a tool attaching / detaching apparatus according to an embodiment of the present invention.

1 and 2, FIG. 1 is a longitudinal sectional view of a tool front end side of a tool attaching / detaching apparatus, and FIG. 2 is a longitudinal sectional view of a tool rear end side of the tool attaching / detaching apparatus. The tool attachment / detachment device is configured by connecting the chain lines X.

In FIGS. 1 and 2, reference numeral 1 denotes a main shaft having an insertion hole 2, and a tool 3 is attached to and detached from a front end of the insertion hole 2. The tool 3 has a shank 3A fitted and held in a tapered portion 2A formed at the front end of the insertion hole 2 of the main shaft 1, and a pull stud 3B provided at the rear end of the shank 3A.

The main shaft 1 has a sleeve 4 fitted inside the inner peripheral wall 2B of the insertion hole 2, and the sleeve 4 is formed with an inner peripheral inclined surface 5 whose diameter increases rearward. A small-diameter inner peripheral wall 2C protruding inward from an inner peripheral wall 2B is formed in the insertion hole 2 of the main shaft 1. The boundary between the inner peripheral wall 2B and the small diameter inner peripheral wall 2C constitutes a step 2D.

A front sleeve 6 is fixed to the inner peripheral wall 2B in the insertion hole 2 of the main shaft 1 at a position forward of the inner peripheral inclined surface 5 of the insertion hole 2. On the inner peripheral wall of the front sleeve 6, a claw receiving portion 6A having an inclined surface whose diameter increases forward is formed.

In the insertion hole 2 of the main shaft 1, a fixed projection made of a thick collar 7 is fixed to the inner peripheral wall 2B at a position behind the inner peripheral inclined surface 5 of the insertion hole 2. I have. Reference numeral 8 denotes a draw bar, which is movably inserted into the insertion hole 2 of the main shaft 1 along the axial direction, and has a rod-shaped portion 9 and a large-diameter portion 10 formed in the middle of the rod-shaped portion 9 and having a larger diameter than the rod-shaped portion 9. And a contact portion 11 composed of a stepped portion is formed from the rod portion 9 to the front end of the large diameter portion 10.

The draw bar 8 has an annular groove portion 13 which is located behind the large diameter portion 10 and has a wedge surface 12 whose diameter is reduced rearward as a front groove wall surface. A spring receiver 14 is provided at a rear end portion. It is fixed via a double nut 14a.

In the insertion hole 2, a tool gripping member 15 is located on the outer periphery on the front end side of the draw bar 8 and is movably disposed a predetermined distance. The tool gripping member 15 includes a cylindrical base 16 formed on the rear end side, and a plurality of locking members (collect chucks) 17 on the front end side integrated with the cylindrical base 16. The cylindrical base 16 is provided with a hole 18 at a rear end thereof at an equal interval along a circumferential direction and penetrating in a radial direction.
Are provided, and a claw 19 is provided at a tip of each locking member 17. When the claws 19 of the locking member 17 are closed, the pull studs 3B of the tool 3 are fixed and tightened, and when opened, the pull studs 3B of the tool 3 are removed and the tightening of the tool 3 is released. It has become.

On the inner peripheral surface of the cylindrical base portion 16 of the tool gripping member 15, a stopper portion formed of a protruding surface 16A with which the contact portion 11 of the draw bar 8 can freely contact is formed. Tool 3
A gap C is formed between the contact portion 11 of the draw bar 8 and the protruding surface 16A at the time of tightening, and the contact portion 11 of the draw bar 8 comes into contact with the protruding surface 16A when the tool 3 is released. Has become.

As shown in FIG. 3, a sphere 20 is provided in each of the holes 18 at the rear end of the tool gripping member 15, and the sphere 20 is formed in the annular groove 1 of the draw bar 8 when the tool 3 is tightened.
3 and the inner peripheral inclined surface 5 of the insertion hole 2 of the main shaft 1 and the annular groove 13 when the tool 3 is released.
It is to be supported inside.

The collar 7 in the insertion hole 2 of the spindle 1
Between the spring bar 14 and the rear end of the draw bar 8
1 and the disc spring 21 constantly urges the draw bar 8 in a direction of pulling the draw bar 8 backward.

A pusher 22 is arranged on the axis at a position spaced a predetermined distance from the rear end face of the draw bar 8, and this pusher 22 has a piston 22A and is configured to be operated by a hydraulic cylinder. When the tightening is released, the draw bar 8 is pressed against the urging force of the disc spring 21 without pressing the draw bar 8.

In this embodiment, as shown in the upper half of the center line in FIGS. 1 and 2, when the push of the draw bar 8 by the pusher 22 is released, the disc spring 21
The pawl 19 of the tool gripping member 15 is closed by the urging force to grip the pull stud 3B of the tool 3, and the tool 3 is tightened.

As shown in the lower half of the center line in FIGS. 1 and 2, when the draw bar 8 is pressed by the pusher 22 against the urging force of the disc spring 21, the tool gripping member 1
5 is opened, and the tool 3 is released from being tightened.

The details will be described below. After the tool 3 is mounted on the main shaft 1 by the automatic tool switching device, when the tool 3 is tightened and fixed to the main shaft 1, the pressing of the rear end face of the draw bar 8 by the piston 22A of the pusher 22 is released. Thus, the drawbar 8 is pressed by the urging force of the disc spring 21.
Retreats, and accordingly, the tool gripping member 15 also retreats via the sphere 20, the claws 19 of the tool gripping member 15 close, and the claws 1
9, the pull stud 3B provided at the tip of the shank 3A of the tool 3 is gripped, and the tool 3 is tightened.

The retraction of the tool holding member 15 is stopped by the engagement of the pull stud 3B of the tool 3 with the claw 19 of the tool holding member 15, and the tool holding member 15 is balanced with the urging force of the disc spring 21. . At this time, the sphere 20 that has fallen into the annular groove 13 moves in the outer diameter direction and abuts the inner peripheral inclined surface 5 of the insertion hole 2, and in this state, the draw bar 8 is further moved backward by the disc spring 21. , The wedge surface 12 of the draw bar 8 comes into contact with the sphere 20, and the sphere 20 is pressed in a direction perpendicular to the wedge surface 12 to be balanced.

In this state, the sphere 20 is placed on the drawbar 8
The wedge surface 12, the inner peripheral inclined surface of the insertion hole 2, and the wall surface of the hole 18 of the tool gripping member 15 are balanced in three-point contact. Therefore, the wedge surface 12 of the drawbar 8 and the insertion hole of the spindle 1
The inner peripheral inclined surface of the portion 2, the hole 18 of the tool gripping member 15
The contact between the points closes the tool gripping member 15 and tightens the tool 3.
And the biasing force of the disc spring 21 is not increased.
Accordingly, the tightening force of the tool 3 increases. When a pulling force F (a force for pulling the tool 3 forward) is applied to the tool 3 during cutting, the tool gripping member 15 and the drawbar 8 are connected to the sphere 2.
0, the pulling force F is transmitted to the sphere 20 via the tool gripping member 15, and the sphere 20 is connected to the wall 18 of the hole 18 of the tool gripping member 15 as shown in FIG.
A is pushed forward by A, and the pulling force F is borne by the wedge surface 12 of the draw bar 8 and the inner peripheral inclined surface 5 of the insertion hole 2.

Then, a pressing force R perpendicular to the wedge surface 12 is transmitted to the wedge surface 12 of the draw bar 8 via a sphere 20 subjected to a pulling force F. An axial component of the pressure R acts . Tool 3 pull-out force
Is the biasing force of the disc spring 21 and the inner circumference of the insertion hole 2 of the spindle 1.
Fishing with the sum of the reaction force that the inclined surface 5 gives to the sphere 20 and fishing
Fit.

When the tool 3 is removed from the main spindle 1 by the automatic tool changer after the cutting process is completed, when the tool 3 is switched from the tightened state to the tool 3 released state, the piston 22A of the pusher 22 is used to remove the plate. The rear end face of the draw bar 8 is pressed against the urging force of the spring 21. As a result, the draw bar 8 moves forward with the tool gripping member 15 stopped, and the sphere 20 falls into the annular groove 13 of the draw bar 8 toward the radial center direction as shown in FIG. It becomes the state of the dotted line. When the draw bar 8 advances by a predetermined distance (gap C), the contact portion 11 of the draw bar 8 contacts the protruding surface 16A of the tool gripping member 15,
The tool gripping member 15 is moved forward as the draw bar 8 advances, and the tightening of the tool 3 by the claws 19 of the tool gripping member 15 is released. Further, the tool gripping member 15 moves forward, but the front end of the cylindrical base 16 abuts on the step 2D of the inner peripheral wall 2B of the insertion hole 2 and stops.

According to the above construction, the draw bar 8 and the tool gripping member 15 are separated from each other so that the draw bar 8 and the tool gripping member 15 can be moved relative to each other. 20 and this sphere 20
Is located in the annular groove 13 of the drawbar 8,
By moving the draw bar 8 forward or backward, the sphere 20 is moved in the radial direction and the axial direction, whereby the sphere 20 in the annular groove 13 is moved to the wedge surface 12 of the draw bar 8 and the inner peripheral inclined surface of the insertion hole 2 of the main shaft. 5, 3 of the hole 18 of the tool gripping member 15
The contact between the points allows the tool gripping member 15 to be closed and the tool 3 to be tightened. In addition, the tool gripping member 15 is opened while the sphere 20 is loosely supported in the annular groove portion 13 and the tool 3 Tightening can be released. That is, sphere 2
0, no special mechanism for moving the tool gripping member 15 is required.

In the above configuration, the force from the sphere 20 and the urging force of the disc spring 21 are simultaneously applied to the draw bar 8,
By adopting a structure in which a part of the pulling force of the tool 3 is borne by the inner peripheral inclined surface 5 of the insertion hole 2 of the main shaft 1, the tool 3 is pulled out when the tool 3 is tightened due to the above-mentioned three-point contact. the force F, the wedge surface 12 of the drawbar 8 can be borne by the inner circumferential inclined surface 5 of the insertion hole 2 of the spindle 1. Furthermore, the wedge surface 12 of the drawbar 8,
Inner peripheral inclined surface 5 of insertion hole 2 of main shaft 1, tool gripping member 15
Of the contact between the three points of the hole 18, Ku such that increasing the biasing force of the disc spring 21, size of the person the tool attachment apparatus, the clamping force of the tool 3 with a simple structure without complicating In growth
Wear.

The pulling force F acting on the tool 3 is transmitted to the sphere 20 via the tool gripping member 15 and further to the wedge surface 12 of the draw bar 8, and the draw bar 8 itself transmits the drawing force F. Not on route. Also, the disc spring 21
Is not located in the middle of the transmission path of the pulling force F, so that the claw 19 of the tool gripping member 15 to which the pulling force F is applied from the tool 3
And the wedge surface 12 of the draw bar 8 can be brought close to each other. Therefore, the transmission path of the pulling force F can be shortened, the drawbar 8 can be prevented from being stretched and the drawbar 8 can be prevented from being absorbed halfway, and the pulling force F from the claw 19 can be prevented. The wedge surface 12 of the drawbar 8
And the tool 3 can be securely tightened with a simple structure.

[0037]

[Effects of the Invention] As described above, according to the present invention,
Since the draw bar and the tool gripping member are separate bodies and the draw bar and the tool gripping member are configured to be relatively movable, a sphere is provided in the hole of the tool gripping member, and the sphere is located in the annular groove of the draw bar. The sphere is moved in the radial and axial directions by advancing or retreating the draw bar, whereby the sphere in the annular groove is moved by the wedge surface of the draw bar, the inner peripheral inclined surface of the insertion hole of the main shaft, and the hole of the tool gripping member. The tool is clamped by closing the tool gripping member by contact between the three points of the portion, and by releasing the tool gripping by opening the tool gripping member with the sphere loosely supported in the annular groove. it can.
That is, a special mechanism for moving the sphere and the tool gripping member is not required.

In the above configuration, a structure is employed in which the force from the sphere and the urging force of the spring material are simultaneously applied to the draw bar, and a part of the pulling force of the tool is borne by the inner peripheral inclined surface of the insertion hole of the main shaft. Thus, when the tool is tightened by the contact between the three points, the pulling force of the tool can be borne by the wedge surface of the draw bar and the inner peripheral inclined surface of the insertion hole of the main shaft . In addition, the drawbar
Wedge surface, the inner peripheral inclined surface of the insertion hole of the spindle,
The contact between the three points of the hole, such that increasing the urging force of the spring member Ku, size of the equipment, it is possible to increase the clamping force of the tool with a simple structure without complicating.

Further, the pulling force acting on the tool is transmitted from the tool gripping member to the wedge surface of the draw bar via the sphere, and the draw bar itself is not located on the transmission path of the pulling force. Further, since the spring member is not located in the middle of the drawing force transmission path, the claw of the tool gripping member to which the drawing force acts from the tool can be brought close to the wedge surface of the draw bar. Therefore, the transmission path of the pullout force can be shortened, the drawbar can be prevented from being stretched and the drawbar can be prevented from being absorbed in the middle, and the pullout force from the claw can be reliably reduced. The effect is transmitted to the wedge surface, and the tool can be securely tightened with a simple structure.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a front end side of a tool of a tool attaching / detaching apparatus according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of a tool rear end side in the tool attaching / detaching device.

FIG. 3 is a cross-sectional view showing the vicinity of the sphere in FIG. 2;

4 is an enlarged vertical sectional view showing the behavior of the sphere in FIG. 2 in the vicinity of the sphere.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main shaft 2 Insertion hole part 2B Inner peripheral wall 3 Tool 5 Inner peripheral inclined surface 7 Collar (fixed protrusion) 8 Drawbar 11 Contact part 12 Wedge surface 13 Annular groove part 14 Spring support 15 Tool gripping member 16A Projection surface (stopper part) 18 Hole 19 Claw 20 Sphere 21 Disc spring (spring material) 22 Pusher C Clearance

Claims (1)

(57) [Scope of request for utility model registration] 1. An insertion hole through which a tool is attached and detached is formed.
A main shaft having an inner peripheral inclined surface that expands in a rearward direction on an inner peripheral wall of the insertion hole portion, a contact portion movably inserted into the insertion hole portion of the main shaft, and protruding outward; A drawbar having an annular groove portion having a front groove wall surface with a wedge surface which is located rearward of the abutting portion and contracts in a rearward direction, and in an insertion hole portion, which is located on an outer periphery of the drawbar and has a predetermined distance. A claw that is arranged movably in the axial direction and that tightens the tool when closed and releases the tool when opened is provided at the front end, and a hole is formed at the rear end along the circumferential direction. A plurality of stoppers are provided at a position separated by a predetermined gap from the contact portion of the draw bar when the tool is tightened, and are moved inside when the tool is released to be in contact with the contact portion of the draw bar. Tool holding member, and provided in each hole at the rear end of the tool holding member. And a sphere that abuts against the wedge surface of the annular groove of the draw bar and the inner peripheral inclined surface of the insertion hole of the main shaft when the tool is tightened, and is freely supported in the annular groove when the tool is released from being tightened; A fixing projection fixed to the inner peripheral wall at a position behind the inner peripheral inclined surface of the insertion hole, a spring receiver fixed to the rear end of the drawbar, and fixing the main shaft in the insertion hole. A spring material that is mounted between the projection and the spring receiver at the rear end of the drawbar, and constantly urges the drawbar backwards; a tool that does not press the drawbar forward when tightening the tool, and a spring when releasing the tool from being tightened; And a pusher for pressing the drawbar forward against the urging force of the material.