JPH08243814A - Clamp mechanism of tool - Google Patents

Abstract

PURPOSE: To provide the clamp mechanism of a tool capable of exhibiting its efficient clamp force between the tool and its main body by movably attaching a contact member to a clamp sleeve and providing an engaging surface making contact with a contact member on the inner wall of a cylindrical tool holder. CONSTITUTION: When a draw bar 20 is moved in an arrow mark direction, a ball 24 is moved upward while making contact with the slant surface 32 of the draw bar 20 and brought in contact with the engaging surface 14 of the inner wall of a tool holder 12. Owing to contact of ball 24 with the engaging surface 14 of the inner wall of the tool holder 12 in this way, the tool holder 12 becomes impossible to be released so as to be clamped to a main body 16. In this case, the slant angle of the engaging surface 14 of the tool holder 12 is set larger than the slant angle of the slant surface 34 of a hole 28 leading to both inside and outside of a clamp sleeve 18. Therefore, when the ball 24 is positioned in the outside of the hole, the ball 24 makes certain contact with the engaging surface 14 of the tool holder 12 so that the tool holder 12 can be intensively clamped to the main body 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clamping mechanism for fastening a cutting tool in a high speed rotating spindle,
In particular, the present invention relates to a clamp mechanism that obtains a large fastening force with a small force.

[0002]

2. Description of the Related Art The structure of a conventional tool clamping mechanism is shown in FIG.
FIG. 7 shows an enlarged cross-sectional view of the essential part in the state shown in FIG. The tool 40 is connected to a tool holder 42 that supports the tool 40, and the side of the tool holder 42 opposite to the tool 40 is formed in a tubular shape. Tool 4
The main body 44 of the rotating means for rotating 0 is formed in a tubular shape, and the tool holder 42 is housed inside the tip of the tubular main body 44. Inside the cylindrical main body 44, a draw bar 46 that is movable in the axial direction with respect to the main body 44 and an engaging member 48 that is fixed to the outer periphery of the distal end of the draw bar 46 are provided. On the outside of the engagement member 48, a tubular clamp collet 50 is arranged so as to face the inner wall of the tubular tool holder 42 and the inner wall of the tubular main body 44.

On the outer surface of the cylindrical clamp collet 50,
A first engaging inclined surface 52 and a second engaging inclined surface 54 are formed. An inclined surface 56 that engages with the first engaging inclined surface 52 is provided on the cylindrical inner wall of the main body 44. The clamp collet 50 always keeps the same positional relationship as the main body 44. That is, the clamp collet 50
Is urged in one direction by a disc spring 60 via an intermediate member 58, and the first engaging inclined surface 52 of the clamp collet 50 and the inclined surface 56 of the main body 44 are always brought into contact with each other by the urging force of the disc spring 60. As a result, the main body 44 and the clamp collet 50 are always kept in the same positional relationship.

In the clamp collet 50, on the side facing the tool 40, a plurality of slits 62 are provided in the axial direction.
Are formed (FIG. 8). The engaging member 48 fixed to the draw bar 46 is set to have a size and a shape that come into contact with the inner wall of the clamp collet 50 in which the slot 62 is formed. That is, when the draw bar 46 is displaced and the engaging member 48 contacts the inner wall of the clamp collet 50, the outer diameter of the clamp collet 50 at the place where the slot 62 is formed becomes relatively large (FIG. 6). When the engaging member 48 does not contact the inner wall of the clamp collet 50, the outer diameter of the clamp collet 50 at the place where the slot 62 is formed is relatively small (FIG. 7).

On the cylindrical inner wall of the tool holder 42, the second engaging inclined surface 5 of the clamp collet 50 is provided.
An inclined surface 64 is provided for engaging with 4. here,
When the engaging member 48 contacts the inner wall of the clamp collet 50 and the outer diameter of the clamp collet 50 is relatively increased, the second engaging inclined surface 54 of the clamp collet 50.
Engage the inclined surface 64 of the tool holder 42. By this engagement, the tool holder 42 does not come off from the clamp collet 50, and the tool 40 and the main body 48 are connected (FIG. 6). On the contrary, when the engaging member 48 stops contacting the inner wall of the clamp collet 50, the outer diameter of the clamp collet 50 becomes relatively small, and the second engaging inclined surface 54 of the clamp collet 50 and the tool holder 42. The inclined surface 64 is no longer engaged. As a result, the tool holder 42 is no longer connected to the clamp collet 50, and the tool 40 can be removed from the main body 48 (FIG. 7).

[0006]

In this conventional clamp mechanism, the portion of the clamp collet 50 where the slit 62 is formed spreads outward, and the second engaging inclined surface 54 of the clamp collet 50 is located on the tool holder 42. Inclined surface 64
By engaging with, the tool 40 and the main body 48 are connected. Therefore, depending on the position of the clamp collet 50, the divided collets are not always fixed at the same position with respect to the rotation center XX depending on the posture at the time of clamping, and the dynamic balance is adversely affected. Further, when the tool holder 42 is not provided, the position of the clamp collet 50 is unstable. In addition, the respective inclined surfaces 54 and 6 to be engaged
4 and the inclined surfaces 52 and 56 are in surface contact with each other, so that the clamping force loss due to friction is large.

The present invention has been made in view of the above point, and the tool is tightly fastened to the main body of the rotating means so that the dynamic balance is good and the pulling force of the drawbar is efficiently used as the clamping force of the tool. The purpose is to provide.

[0008]

In order to achieve the above object, the present invention detachably mounts a cylindrical tool holder integrally formed with a tool inside a cylindrical body of a means for rotating the tool. A tool clamping mechanism, wherein a tubular clamp sleeve is fixed to the main body in a state where at least a part is located inside the tubular tool holder,
The cylindrical clamp sleeve is provided with a hole that communicates with the inside and outside of the cylinder, and a contact member that can pass through the hole is movably attached to the clamp sleeve, and the axial direction of the clamp sleeve is inside the cylindrical clamp sleeve. An inner wall of the cylindrical tool holder having a movable drawbar, and forming a protrusion adjusting surface on the surface of the drawbar for adjusting the degree of contact with the contact member and protruding the contact member from the hole. An engaging surface for contacting the contact member is provided, and the contact member projects outside the clamp sleeve and contacts the engaging surface of the tool holder to fasten the tool holder and the main body. The tool holder and the body by tightening the contact member so that the contact member does not contact the engaging surface of the tool holder. In which it was to be divided.

[0009]

When connecting the main body and the tool holder, the ball is projected outward from the hole of the clamp sleeve and brought into contact with the engaging surface of the inner wall of the tool holder. In this way, by directly contacting the ball with the engagement surface of the tool holder, the clamping force loss due to the frictional force can be reduced as compared with the conventional fastening by engaging the inclined surfaces with each other. As a result, the tool holder can be efficiently clamped. Further, since only this ball moves in the radial direction, the mass is small with respect to the clamp collet and the influence on the dynamic balance is small.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of an embodiment showing a clamp state of a tool clamping mechanism according to the present invention, FIG. 2 is a sectional view showing a non-clamping state of a tool clamping mechanism according to the present invention, and FIG.
FIG. The tip of the cylindrical tool holder 12 of the tool 10 has a cylindrical shape.
An engagement surface 14 is formed on the inner wall of the tubular member 2. The main body 16 of the rotating means for rotating the tool 10 is formed in a tubular shape, and the tool holder 12 is housed inside the tip of the tubular main body 16. A tubular clamp sleeve 18 is provided inside the tubular body 16 in a state of being fixed to the body 16. A part of the clamp sleeve 18 is located inside the tubular shape of the tool holder 12. A draw bar 20 is provided inside the cylindrical clamp sleeve 18 so as to be movable with respect to the clamp sleeve 18.

A plurality of stopper plates 22 are swingably attached to the clamp sleeve 18.
A ball 24 as a contact member is rotatably attached to the swinging tip of 2 (FIG. 4). A through hole 26 is provided in the ball 24 for inserting the stopper plate 22. The diameter of the through hole 26 is set to be sufficiently larger than the diameter of the stopper plate 22. The contact member is preferably a ball 24, but is not limited to this shape. A plurality of holes 28 (FIG. 2) communicating with the inside and outside of the cylinder are formed in the clamp sleeve 18, and the balls 24 are set so as to be able to move in and out of the clamp sleeve 18 through the holes 28. A recess 30 for fitting with the ball 24 is formed on the outer wall of the draw bar 20, and an inclined surface 32 is formed from the position of the recess 30 toward the tip end of the draw bar 20. The recess 30 and the inclined surface 32 are projection adjusting surfaces for adjusting the degree to which the ball 24 projects from the hole 28.

As shown in FIG. 5, the clamp sleeve 18
The wall surface of the hole 28 formed in the above is an inclined surface 34. This inclined surface 34 moves the ball 24 along the inclined surface 34 when the ball 24 comes into contact therewith, and
The inclination angle is set so that 4 contacts the draw bar 20. Further, as shown in FIG. 5, the tool holder 1
The engaging surface 14 of the inner wall of 2 is inclined by an angle α ° with respect to the surface perpendicular to the axial direction of the tool holder 12. The inclined surface 34 formed in the hole 28 that communicates with the inside and outside of the clamp sleeve 18 is in a state of being inclined at an angle β ° with respect to the surface of the clamp sleeve 18 that is perpendicular to the axial direction. Drawbar 2
The inclined surface 32 formed at 0 is inclined by an angle γ ° with respect to the central axis of the drawbar 20. Where α
Set so that> β.

As described above, the ball 24 contacts the inclined surface 34 of the clamp sleeve 18, and the inclination angle of the inclined surface 34 causes the ball 24 to always contact the draw bar 20. Here, the draw bar 20 is moved in the arrow direction from the state of FIGS. 1 and 5 in which the ball 24 is in contact with the inclined surface 34 of the clamp sleeve 18 and the inclined surface 32 of the draw bar 20. This movement of the draw bar 20 causes the ball 24 to move upward in FIGS. 1 and 5 while contacting the inclined surface 32 of the draw bar 20.
Contacts the engagement surface 14 on the inner wall of the tool holder 12.
In this way, the ball 24 comes into contact with the engagement surface 14 of the inner wall of the tool holder 12 so that the tool holder 1
When the tool holder 12 does not come off, the tool holder 12 is fastened to the main body 16. At this time, the inclination angle α of the engagement surface 14 of the tool holder 12 is set to be larger than the inclination angle β of the inclination surface 34 of the hole 28 that communicates with the inside and outside of the clamp sleeve 18, so that the ball 24 is outside the hole 28. When it is positioned at, the ball 24 surely contacts the engaging surface 14 of the tool holder 12, and the tool holder 12 can be tightened to the main body 16 with a strong tightening force. As a result, the abutting surface 36 between the tool holder 12 and the main body 16, the tool holder 12 and the main body 1
The taper joint surface 38 and 6 can be closely adhered.

Next, when the fastening between the tool holder 12 and the main body 16 is released, the draw bar 20 is moved in the direction opposite to the arrow from the state shown in FIGS. Since the ball 24 is always in contact with the draw bar 20, when the draw bar 20 is moved in the direction opposite to the arrow, the ball 24 will be in the recess 30.
(Fig. 2). In the state of FIG. 2 in which the ball 24 is aligned with the recess 30, the ball 24 does not project outside the outer surface of the clamp sleeve 18. As a result, ball 2
4 does not hinder the movement of the tool holder 12, and the tool holder 12 can be removed from the main body 16. Since the ball 24 is attached to the clamp sleeve 18 via the stopper plate 22, even when the tool holder 12 is detached from the main body 24, the ball 24 is attached to the main body 24.
It does not come off.

[0015]

As described above, according to the tool clamping mechanism of the present invention, the tool and the rotating means main body are attached by bringing the ball attached to the main body into contact with the engaging surface of the tool holder. Is. In this way, the ball directly presses the engaging surface of the tool holder, so that a higher clamping effect can be obtained as compared with the conventional one in which the inclined surfaces are simply engaged with each other.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment showing a clamped state of a tool clamping mechanism according to the present invention.

FIG. 2 is a cross-sectional view showing a non-clamping state of a clamping mechanism for a tool according to the present invention.

FIG. 3 is a sectional view taken along line AA of FIG. 1;

FIG. 4 is a configuration diagram of a ball and a clasp used in the present invention.

5 is an enlarged cross-sectional view of a main part of FIG.

FIG. 6 is a cross-sectional view of a conventional clamp mechanism.

FIG. 7 is an enlarged cross-sectional view showing a non-clamped state of the conventional clamp mechanism shown in FIG.

FIG. 8 is a cross-sectional view of a clamp collet used in a conventional clamp mechanism.

[Explanation of symbols]

 10 Tool 12 Tool Holder 14 Engagement Surface 16 Main Body 18 Clamp Sleeve 20 Drawbar 22 Stopper 24 Ball 28 Hole 30 Recess 32 Slope 34 Slope

[Procedure amendment]

[Submission date] April 19, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction content]

Next, when the fastening between the tool holder 12 and the main body 16 is released, the draw bar 20 is moved in the direction opposite to the arrow from the state shown in FIGS. Since the ball 24 is always in contact with the draw bar 20, when the draw bar 20 is moved in the direction opposite to the arrow, the ball 24 will be in the recess 30.
(Fig. 2). In the state of FIG. 2 in which the ball 24 is aligned with the recess 30, the ball 24 does not project outside the outer surface of the clamp sleeve 18. As a result, ball 2
4 does not hinder the movement of the tool holder 12, and the tool holder 12 can be removed from the main body 16. Since the ball 24 is attached to the clamp sleeve 18 via the stopper plate 22, the tool holder 12 is attached to the main body.
Even in a state which was removed from the 16, the ball 24 is the main body 16
It does not come off.

Claims (2)

[Claims] 1. A clamp mechanism for a tool, wherein a tubular tool holder coupled to a tool is detachably attached to an inside of a tubular body of a means for rotating the tool, the inside of the tubular tool holder. A cylindrical clamp sleeve is fixed to the main body in a state where at least a part thereof is located, a hole communicating with the inside and outside of the cylinder is provided in the cylindrical clamp sleeve, and a contact member capable of passing through the hole is provided in the clamp sleeve. A draw bar movable in the axial direction of the clamp sleeve is provided inside the cylindrical clamp sleeve, the draw bar being in contact with the contact member and projecting the contact member from the hole. A protrusion adjusting surface for adjusting the degree is formed, and an engagement surface for contacting the contact member is provided on the inner wall of the cylindrical tool holder, and the contact member is The tool holder and the main body are fastened by projecting to the outside of the clamp sleeve and contacting the engaging surface of the tool holder, and the contact member retracts inside the clamp sleeve so that the contact member does not contact the engaging surface of the tool holder. By doing so, the tool clamping mechanism is characterized in that the fastening between the tool holder and the main body is released. 2. A clamp mechanism for a tool according to claim 1, wherein a stopper plate is swingably attached to the clamp sleeve, the contact member is a ball, and the ball is rotatably attached to the stopper plate. .