JP3353694B2 - Tool holder mounting device and tool holder temporary holding method - 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 holder mounting device for inserting and fixing a hollow taper shank of a tool holder into a tapered hole of a main shaft of a machine tool, and a method for temporarily holding a tool holder.

[0002]

2. Description of the Related Art In an automatic machine tool such as a machining center equipped with an automatic tool changer (ATC), a plurality of tools suitable for a predetermined cutting process are respectively mounted on a tool holder. The exchange device exchanges a new tool with a tool that has already been mounted on the tip of the spindle of the machine tool and has been machined.

[0003] In the exchange operation, for example, an ATC arm provided with a tool gripper at each end capable of gripping another tool and rotatable around a central portion in the longitudinal direction at a predetermined position is provided. Is moved to the center of the tool grip at one end, that is, the ATC position. After the replacement, the spindle is moved to the original position, and machining is performed with the newly mounted tool.

FIG. 12 shows a state in which a tool holder 3 having a tool (not shown) is mounted on a left end of a main shaft 1 of a machine tool such as a machining center in the drawing.
Shows a state in which the tool holder 3 is temporarily held on the main shaft 1.

The main shaft 1 is rotatable via a bearing with respect to a housing (not shown) of the machine tool. The main shaft 1 has a tapered hole 5 at the tip, and a hollow tapered shank 7 of the tool holder 3 is inserted into the tapered hole 5. I have. In the tool holder 3, the outer peripheral surface of the hollow taper shank 7 and the flange end surface 3 a are tightly constrained to the main shaft 1 side, and are restricted.
This is a so-called two-plane constraint type, and corresponds to high-speed cutting.

[0006] A pair of collets 9 are accommodated in the tapered hole 5 so as to be movable in the radial direction of the main shaft 1.
It is held on the main shaft 1 by an engagement holding portion 9a at the right end in the drawing. The left end of the collet 9 has a locking portion 9b.
On the inner surface of the tapered hole 5, a locking portion 7a that can be locked to the locking portion 9b is formed. Further, inside the collet 9 in the tapered hole 5, a drawbar 11 movable in the left-right direction in the drawing is accommodated.

When the draw bar 11 is moved rightward from the state shown in FIG. 13, the collet 9 is expanded, and the locking portion 9b is locked in the locking portion 7a on the tapered hole 7 side, so that the hollow taper shank is formed. 7 is elastically deformed radially outward. As a result, the outer peripheral surface of the hollow tapered shank 7 comes into close contact with the tapered hole 5 and the flange end surface 3a comes into close contact with the end surface of the main shaft 1, so that the tool holder 3 is held on the main shaft 1 as shown in FIG. .

A through hole 7b for temporary support is formed at a position in the circumferential direction of the hollow tapered shank 7 opposite to each other. On the other hand, a sphere 13 such as a steel ball and a spring 15 for pressing the sphere 13 into the through-hole 7b are provided on the main shaft 1 at a position facing the through-hole 7b.

When the sphere 13 is pressed by the spring 15 and partially enters the through hole 7b, the tool holder 3
Is held on the spindle 1 side, and as shown in FIG.
1 is located on the left side in the figure, and the tool holder 3 is temporarily held in a state where the tool holder 3 is not held by the collet 9.

As another tool holder mounting device provided with such a temporary holding mechanism, there is one described in Japanese Patent Application Laid-Open No. 8-118118. In this publication, holding levers for temporarily holding a tool holder are provided at positions facing each other in a circumferential direction between a plurality of collets arranged in the circumferential direction. .

The holding lever itself is made of a material which is easily elastically deformable, such as spring steel, and has a structure in which the locking portion at the tip is pressed against the locking portion on the inner surface of the hollow taper shank to temporarily hold the holding lever. Has become. The holding lever has such an elastic force that it can be elastically deformed in the radial direction of the main shaft by the attachment / detachment force of the tool holder to the main shaft by the automatic tool changer.

[0012]

However, in the tool holder mounting device shown in FIGS. 12 and 13, the hollow tapered shank 7 is used as a temporary holding mechanism.
When the hollow tapered shank 7 is pushed radially outward by the collet 9 and is elastically deformed, stress is concentrated in the through hole 7b, so that cracks are easily formed, and the durability of the tool holder 3 is improved. Have difficulty.

Further, since the hollow tapered shank 7 has the through holes 7b, (1) the area of the fastening surface of the main shaft 1 with respect to the tapered hole 5 is reduced, and (2) deformation due to location when elastically deformed. Differences in the amount occur, and (3) the gravity balance deteriorates. For these reasons, the fastening force is reduced and the unbalance during rotation is increased. There is a problem that it cannot sufficiently adapt to the high-speed rotation corresponding to the holder.

On the other hand, the tool holder mounting device disclosed in Japanese Patent Application Laid-Open No. Hei 8-118118 has a configuration in which the inner surface of the hollow taper shank is temporarily held by the holding lever, so that it is necessary to provide a through hole in the hollow taper shank. Not
Therefore, the above-mentioned problem is solved. However, this is the same as the tool holder mounting device shown in FIGS. 12 and 13, except that the tool holder is provided with a hollow and lightweight hollow tapered shank and the center of gravity is located closer to the tool holding side. Since such a tool holder is temporarily held on the main shaft at two points facing each other in the circumferential direction, a moment due to its own weight acts, the positioning stability at the time of temporary holding deteriorates, and the hollow taper due to the collet. There is a problem that the locking operation with respect to the shank is not reliably performed.

Further, in any of the above tool holder mounting devices, since the portion of the tool holder temporarily held is located on the hollow taper shank, the moment due to the above-mentioned own weight is large, and the positioning stability at the time of the temporary holding is improved. It will be extremely bad.

Therefore, the present invention prevents the tool holder from deteriorating in durability and can be adapted to high-speed rotation.
The purpose is to improve the positioning stability during temporary holding.

[0017]

In order to achieve the above object, a first aspect of the present invention is a hollow taper shank of a tool holder inserted into a tapered hole of a main shaft, and a radially outer portion provided in the tapered hole. To the inner peripheral surface of the hollow taper shank inserted into the tapered hole by moving to the inner peripheral surface of the tapered hole. A tool holder mounting device having a draw bar for moving the collet radially outward, wherein the collet is formed continuously from the hollow hole of the hollow taper shank toward the tool holding portion side of the tool holder in the tool holder. A hollow portion is provided, and an enlarged portion inserted into the hollow portion is provided at the tip of the drawbar, and the drawbar moves forward in the main shaft so that the enlarged portion is hollow. In the state where the collet is located radially inward, the temporary holding portion for temporarily holding the tool holder with respect to the main spindle, the outer peripheral surface of the enlarged portion of the draw bar, and the hollow portion of the hollow taper shank Provided between the inner surface, the temporary holding portion, the concave portion provided in one of the enlarged portion and the hollow portion, and provided in a state where the movement in the axial direction is restricted to one of the other, in the concave portion And an elastic body that enters.

According to the tool holder mounting device having such a configuration, the tool is moved in a state in which the draw bar moves forward of the main shaft, the collet is positioned radially inward, and the holding of the tool holder by the collet with respect to the main shaft is released. The holder is temporarily held in a stable state on the main shaft side by a temporary holding portion made of an elastic body and a concave portion provided between the enlarged outer peripheral surface of the draw bar and the inner surface of the hollow portion in the tool holder.

[0019]

[0020]

According to a second aspect of the present invention, in the configuration of the first aspect, the concave portion is an annular groove, and the elastic body is a substantially annular elastic ring partially open.

According to the above arrangement, for example, the elastic ring provided on the drawbar side enters the annular groove provided on the tool holder side by its elastic force, whereby the tool holder is temporarily held on the main spindle side.

According to a third aspect of the present invention, in the configuration of the second aspect, sleeves are mounted on the inner surface of the hollow portion of the tool holder and the outer peripheral surface of the draw bar, respectively, and each of the sleeves is provided with an annular groove or an elastic ring. Is provided.

According to the above construction, for example, the elastic ring provided on the outer peripheral surface of the sleeve mounted on the draw bar is inserted into the annular groove provided on the inner peripheral surface of the sleeve mounted on the tool holder. Temporarily held on the side.

According to a fourth aspect of the present invention, in the configuration of the first aspect, the elastic member includes a pair of arc-shaped members provided at positions opposed to each other in a circumferential direction, and a pair of the arc-shaped members having a concave portion. An elastic member that presses against the side, and the concave portion is configured by a groove into which the arc-shaped member enters.

According to the above configuration, for example, the arc-shaped member provided on the draw bar side is pressed by the elastic member and enters the groove on the tool holder side, whereby the tool holder is temporarily held on the main spindle side.

According to a fifth aspect of the present invention, in the configuration of the first aspect, the elastic body includes a pair of arc-shaped members provided at positions facing each other in a circumferential direction, and an outer peripheral surface of each of the arc-shaped members. A spherical body protruding radially outward at at least two places along the circumferential direction, and an elastic member that presses the pair of arc-shaped members toward the concave side so that the spherical body enters the concave part. ing.

According to the above configuration, for example, a sphere provided on the drawbar side is pushed into the recess on the tool holder side by being pressed by the elastic member through the arc-shaped member, whereby the tool holder is temporarily held on the main spindle side. Is done.

According to a sixth aspect of the present invention, in the configuration of the fourth or fifth aspect, locking pieces to be locked to a tool holder or a drawbar are fixed to both ends of the pair of arc-shaped members, respectively. Is constituted by a spring that presses the arc-shaped member through the locking piece.

According to the above construction, for example, when the locking piece locked to the draw bar is pressed by the spring, the arc-shaped member or the sphere enters the concave portion on the tool holder side, whereby the tool holder is rotated by the spindle. Temporarily held on the side.

According to a seventh aspect of the present invention, in the configuration of the sixth aspect, the elastic body is provided on an outer peripheral surface of the draw bar,
The spring is disposed between the locking pieces provided at the ends of the pair of arc members, and simultaneously presses the pair of arc members in directions away from each other.

According to the above construction, the locking pieces provided at the ends of the pair of arc-shaped members are simultaneously pressed by the spring, whereby the arc-shaped member or the sphere enters the recess on the tool holder side.

According to an eighth aspect of the present invention, in the configuration of the first aspect, the elastic body includes a sphere that enters the recess and a spring that presses the sphere, and these are provided at at least three locations in the circumferential direction. ing.

According to the above construction, for example, the spheres provided at at least three positions in the circumferential direction of the draw bar are pressed by the spring, so that the spheres enter the recesses on the tool holder side, whereby the tool holder is moved to the main spindle side. Temporarily held.

According to a ninth aspect of the present invention, in the configuration of the fifth or eighth aspect, the concave portion is formed by an annular groove.

According to the above configuration, for example, the spheres provided at at least three positions in the circumferential direction of the draw bar are pressed by the spring, so that the spheres enter the annular groove on the tool holder side.

According to a tenth aspect of the present invention, when the hollow taper shank of the tool holder is inserted into the tapered hole of the main spindle, the collet on the outer peripheral side is moved outward in the radial direction by the rearward movement of the draw bar provided on the main spindle. When moving and fixing the tool holder to the main shaft, or when releasing the fixation, the enlarged part of the tip of the draw bar continuously extends from the hollow hole of the hollow taper shank toward the tool holding part side of the tool holder. In the state inserted in the hollow part formed by
An elastic body provided in a state in which movement in the axial direction is restricted in one of the other, into the concave portion provided in any one of the enlarged portion and the hollow portion, so that the tool holder is attached to the main shaft. This is a temporary holding method for temporarily holding.

According to the above temporary holding method, the draw bar moves forward of the spindle, the collet is positioned radially inward, and the tool holder is held in the state of being released from the collet by the tool holder. The temporary holding portion made of an elastic body and a concave portion provided between the outer peripheral surface of the enlarged portion and the inner surface of the hollow portion in the tool holder is temporarily held in a stable state on the spindle side.

[0039]

According to the first aspect of the present invention, the tool holder is temporarily held on the inner surface of the hollow portion in the tool holder formed continuously with the hollow hole of the hollow taper shank via the enlarged portion at the tip of the draw bar. With this configuration, the portion of the tool holder that is temporarily held is closer to the center of gravity, so that the moment due to its own weight during the temporary holding is reduced, and the positioning stability during the temporary holding can be improved. In addition, since it is not necessary to provide a through hole in the hollow taper shank as a temporary holding portion, it is possible to prevent a decrease in the durability of the hollow taper shank, reduce a fastening area with respect to the main shaft side, a difference in elastic deformation amount depending on a place, or a gravity Deterioration of balance can be avoided, and this can be applied to high-speed rotation. Furthermore, the elastic body provided on one of the enlarged part at the tip of the drawbar and the inner surface of the hollow part in the tool holder enters the recess provided on the other, so that the tool holder can be temporarily held securely on the main spindle side. .

[0040]

According to the second aspect of the present invention, the elastic ring provided on one of the draw bar and the tool holder enters the annular groove provided on the other by its elastic force.
Since the tool holder can be temporarily held securely on the drawbar on the main spindle side, and almost the entire circumference is temporarily held by the elastic ring, the positioning stability at the time of temporary holding can be improved.

According to the third aspect of the present invention, an annular groove or an elastic ring is provided in the sleeve mounted on each of the inner surface of the tool holder and the outer peripheral surface of the draw bar. The cost can be reduced as compared with the case where a tool holder and a drawbar newly provided with an annular groove or an elastic ring are newly prepared.

According to the fourth aspect of the present invention, the arc-shaped member provided on one of the draw bar and the tool holder is pressed by the elastic member and enters the groove provided on the other, so that the tool holder is connected to the spindle. The temporary holding can be reliably performed, and the temporary holding by the arc-shaped member can improve the positioning stability during the temporary holding.

According to the fifth aspect of the present invention, the sphere provided on one of the draw bar and the tool holder is pressed by the elastic member via the arc-shaped member and enters the groove provided on the other, thereby providing a tool. The holder can be temporarily held securely on the spindle side, and at least two holders provided on each arc-shaped member can be provided.
Since the spheres are temporarily held, the positioning stability at the time of the temporary holding can be improved.

According to the sixth aspect of the present invention, the locking piece locked to one of the draw bar and the tool holder is pressed by the spring so that the arc-shaped member or the sphere enters the recess provided in the other. Thus, the tool holder can be securely temporarily held on the spindle side.

According to the seventh aspect of the present invention, the pair of arc-shaped members are simultaneously pressed by the springs disposed between the locking pieces at the ends of the pair of arc-shaped members. The holding operation becomes uniform, and the positioning stability at the time of temporary holding is improved.

According to the invention of claim 8, the spheres provided at at least three places in the circumferential direction in one of the draw bar and the tool holder are pressed by the spring and enter the recess provided in the other, so that the tool can be used. The holder can be temporarily held securely on the main spindle side, and since the holder is temporarily held by at least three spheres, the positioning stability during the temporary holding can be improved. Furthermore, in the case of a tool holder temporarily held on a horizontally arranged spindle,
Since the load of the spring can be changed depending on whether the elastic body including the sphere and the spring is located at the upper part and the elastic body located at the lower part, a more stable temporary holding state can be secured.

According to the ninth aspect of the present invention, since the sphere provided on one of the draw bar and the tool holder is inserted into the annular groove provided on the other, there is no need to position the sphere and the recess. Thus, the work of temporarily holding can be simplified.

According to the tenth aspect of the present invention, the tool holder is temporarily held on the inner surface of the hollow portion of the tool holder formed continuously with the hollow hole of the hollow taper shank via the enlarged portion at the tip of the draw bar. As a result, the portion of the tool holder that is temporarily held is closer to the center of gravity side, the moment due to its own weight during temporary holding is reduced, and the positioning stability during temporary holding can be improved. In addition, since it is not necessary to provide a through hole in the hollow taper shank as a temporary holding portion, it is possible to prevent a decrease in the durability of the hollow taper shank, reduce a fastening area with respect to the main shaft side, a difference in elastic deformation amount depending on a place, or a gravity Deterioration of balance can be avoided, and this can be applied to high-speed rotation. Furthermore, the elastic body provided on one of the enlarged part at the tip of the drawbar and the inner surface of the hollow part in the tool holder enters the recess provided on the other, so that the tool holder can be temporarily held securely on the main spindle side. .

[0050]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a cross-sectional view of the vicinity of the tip of a main shaft 17 of a machine tool such as a machining center according to a first embodiment of the present invention. The normal holding state in which the holder 19 is fastened and fixed to the main shaft 17 is shown in the upper part of FIG.
Reference numeral 9 denotes a temporary holding state where the temporary holding is performed on the main shaft 17 side.

The main shaft 17 is rotatable with respect to a housing of a machine tool (not shown), and a hollow taper shank 23 of a tool holder 19 is inserted into a taper hole 21 provided at an end of the main shaft 17. The tool holder 19 has a flange 25 on the base side of the hollow taper shank 23, and the outer peripheral surface 23 a of the hollow taper shank 23 is attached to the inner peripheral surface of the tapered hole 21 in a state where the tool holder 19 is fastened and fixed to the main shaft 17. At the same time, the end face 25a of the flange 25 comes into close contact with the end face 17a of the main shaft 17. Therefore, the tool holder 19 is of a two-face restraint type in which the tool holder 19 is restrained on the main shaft 17 side by the two faces.

At the left end of the tool holder 19 in the drawing,
A tool (not shown) is mounted, and in this tool mounting state, a tool change is performed by holding a holding groove 25b formed on the outer periphery of the flange 25 by an automatic tool changing device (not shown). Here, it is assumed that the main shaft 17 moves with respect to the automatic tool changer.

A central hole 27 is formed in the main shaft 17 so as to be continuous with the bottom of the tapered hole 21 in the axial direction. The part extending from the center hole 27 to the tapered hole 21 is
A pair of collets 29 movable in the radial direction are accommodated. The pair of collets 29 are divided in the vertical direction in the figure, and are not shown, but the right end in the figure is formed by an engagement holding portion as shown in FIGS. 12 and 13. It is held on the main shaft 17 side.

An outer locking surface 29a is formed outside the left end of the collet 29 in the drawing. The outer locking surface 29a serves to hold the tool holder 19 by locking to the inner locking surface 23b formed on the inner surface of the hollow taper shank 23 when the collet 29 moves radially outward. .

Further inside the collet 29, a draw bar 31 movable in the left and right directions in the figure by a hydraulic mechanism (not shown) is accommodated. The drawbar 31 has a large-diameter enlarged portion 31b whose left end in the figure is larger than the shaft portion 31a.
The pressing contact surface 31c is formed between the enlarged portion 31b and the shaft portion 31a. When the draw bar 31 moves rightward, the pressing surface 31c presses the inside of the tip end of the collet 29 to expand the collet 29 radially outward.

In the flange 25 of the tool holder 19, a hollow portion 25c is formed which is continuous with the hollow hole 23c of the hollow taper shank 23, and the enlarged portion 31b of the draw bar 31 is inserted into the hollow portion 25c during temporary holding. Has become.

At the center of the bottom of the hollow portion 25c, a coolant through nozzle 33 is fixed. The coolant through nozzle 33 is inserted movably in the axial direction into a through hole 31 d formed in the draw bar 31 in the axial direction. A seal member 35 is provided on the inner peripheral surface of the draw bar 31 facing the outer peripheral surface of the coolant through nozzle 33. At the time of cutting, a coolant, which is a coolant, is supplied from the through hole 31d of the draw bar 31 to the tool and the workpiece through the coolant through nozzle 33 and the coolant passage 19a in the tool holder 19 to cool them.

The outer peripheral surface of the enlarged portion 31b and the hollow portion 25c
Annular sleeves 37 and 39 are fixed to the inner peripheral surface by press fitting or the like, respectively. FIG. 3 is an enlarged view around the temporary holding portion in the upper part of FIG. 1 showing the temporary holding state, and FIG. 4 is an enlarged view around the temporary holding part in the lower part of FIG. 1 showing the normal holding state. As shown in these figures, a fitting groove 37a is formed on the outer peripheral surface of the sleeve 37 on the outer periphery of the enlarged portion. As shown in FIG. 2, an elastic ring 41 having a circular cross section made of spring steel as an approximately annular elastic body with a part opened is fitted into the fitting groove 37 a. The fitting groove 37a
The bottom of the elastic ring 41 is formed in a spherical shape having substantially the same curvature as the circular section of the elastic ring 41, and the side surface is formed in the inner surface of the cylinder. The elastic ring 41 can be displaced in the fitting groove 37a in the direction indicated by the arrow R in FIG. 4 along the inner surface of the cylinder.

As shown in FIG. 4, the elastic ring 41 fitted in the fitting groove 37a has a circular center located in the fitting groove 37a and a part thereof protruding from the outer peripheral surface of the sleeve 37. A gap 43 is formed between the fitting groove 37a and the bottom so that the elastic ring 41 can be displaced toward the bottom of the fitting groove 37a. The end of the elastic ring 41 protruding from the outer peripheral surface of the sleeve 37 is connected to the tool holder 1.
It is located radially outward by a dimension t from the inner peripheral surface of the sleeve 39 on the 9th side.

On the other hand, on the inner peripheral surface of the sleeve 39 on the tool holder 19 side, there is formed an annular groove 39a having an arc-shaped cross section as a concave portion into which the elastic ring 41 enters while being elastically pressed. . The annular groove 39a has a depth substantially equal to or slightly smaller than the dimension t.
The draw bar 31 is formed at a position where the elastic ring 41 enters with the distal end surface 31e of the draw bar 31 almost in contact with the bottom of the hollow portion 25c. The annular groove 39a and the elastic ring 41 constitute a temporary holding portion.

The sleeve 39 on the inner periphery of the hollow portion 25c is formed with an inclined surface 39b so that the end on the side of the hollow taper shank 23 is continuous with the curved portion 23d on the inner surface of the hollow hole 23c. The inclined surface 39b serves as a guide for easily moving the elastic ring 41 to the inside of the sleeve 39 when the tool holder 19 is temporarily held.

Next, the operation when the tool holder 19 is mounted on the main shaft 17 will be described. When the draw bar 31 protrudes toward the distal end as shown in the upper part of FIG. 1, the collet 29 is located radially inward. In this state, when the hollow tapered shank 23 of the tool holder 19 gripped by the tool gripping portion of the automatic tool changer is inserted into the tapered hole 21 of the main shaft 17, the elastic ring 41 provided on the outer periphery of the tip of the draw bar 31 becomes Slope 39 of sleeve 39
While being guided by b, it is elastically deformed toward the bottom of the fitting groove 37a and reaches the inner surface of the sleeve 39.

When the tool holder 19 is further pushed into the tapered hole 21, the elastic ring 41 is
Into the annular groove 39a of the tool holder 1
9 is temporarily held on the main shaft 17 side. In this temporary holding state, the distal end surface 31e of the draw bar 31 is
5c, while the outer peripheral surface 23a of the hollow tapered shank 23 has a predetermined gap formed with the tapered hole 21 and the flange end surface 25a has a predetermined gap formed with the main shaft end surface 17a. .

In the temporarily held state, the gripping of the tool holder 19 by the tool gripper of the automatic tool changer is released, and the spindle 17 moves away from the tool changer and moves to the machining position.

When the draw bar 31 is moved rightward in the drawing in the process of moving the main shaft 17 to the machining position, the elastic ring 41 is disengaged from the annular groove 39a and simultaneously pressed by the pressing contact surface 31c of the draw bar 31. The collet 29 moves rightward in the figure while moving outward in the radial direction. Due to this movement, the outer locking surface 29a of the collet 29 is locked to the inner locking surface 23b of the hollow tapered shank 23, and the hollow tapered shank 23 is elastically deformed radially outward, so that the outer peripheral surface 23a is At the same time as the inner surface is in close contact, the flange end surface 25a is also in close contact with the spindle end surface 17a.

As a result, the tool holder 19 is held at the lower part of FIG.
When the movement of the spindle 7 to the machining position is completed, the cutting is performed by the rotation of the main shaft 17. As described above, the spindle 17 can be moved to the processing position while performing the operation of changing from the temporary holding state to the normal holding state, so that the overall operation time can be reduced.
When the tool (tool holder 19) used for processing is removed, the draw bar 31 is protruded and moved from the regular holding state to the temporary holding state in the process of moving the spindle 17 to the tool changing position by the automatic tool changing device. By doing so, the overall work time is reduced.

The temporary holding portion including the elastic ring 41 and the annular groove 39a for temporarily holding the tool holder 19 is provided on the outer peripheral surface of the draw bar 31 and in the hollow portion 25c. As shown in FIG. 13, by providing a through hole in the hollow taper shank, a decrease in the strength of the hollow taper shank is avoided, and the durability of the tool holder 19 is ensured. It can be adapted to high-speed rotation.

Further, since the above-mentioned temporary holding mechanism is configured to hold substantially the entire peripheral portion of the tool holder 19 by the elastic ring 41 provided on the draw bar 31, the positioning stability at the time of the temporary holding is improved. Further, the portion where the tool holder 19 is temporarily held is set at a position closer to the center of gravity on the left side in the figure than the hollow taper shank 23, so that the moment due to its own weight at the time of temporary holding becomes smaller than before.
This also improves the positioning stability. By improving the positioning stability, the locking operation of the outer locking surface 29a of the collet 29 with respect to the inner locking surface 23b of the hollow taper shank 23 is ensured, and the spring force of the elastic ring 41 in the temporary holding mechanism is also reduced. Can be set,
The work of temporarily holding the work becomes easy.

FIG. 5 shows a second embodiment of the present invention. This embodiment eliminates the sleeves 37 and 39 on the outer periphery of the enlarged portion 31b of the draw bar 31 and the inner periphery of the hollow portion 25c on the tool holder 19 side in FIG. The elastic ring 41 is fitted into the fitting groove 31f formed on the outer peripheral surface, and an annular groove 25d is formed on the inner peripheral surface of the hollow portion 25c.

In the example of FIG. 5, the same operation and effect as those of FIG. 1 are obtained. In addition, the thing of the said FIG.
This can be achieved by attaching sleeves 37 and 39 to the tool holder 19 and the main shaft 17 (draw bar 31) in existing equipment not provided with the temporary holding mechanism.
As in the example of FIG. 5, the elastic ring 41 and the annular groove 25
There is no need to newly set the draw bar 31 and the tool holder 19, each of which is directly provided with d, and the cost is lower than that of FIG.

FIGS. 6 and 7 show a third embodiment of the present invention. FIG. 6 is a side view of the vicinity of the expanded portion 45a at the tip of the draw bar 45, and FIG. 7 is a sectional view taken along the line AA of FIG. Fitting grooves 45b are formed at mutually opposing positions on the outer periphery of the enlarged portion 45a, and a pair of arc-shaped members 47 made of spring steel having a circular cross section and being elastically deformable are fitted into the fitting grooves 45b.

The locking pieces 4 are provided at both ends of the arc-shaped member 47.
9 is fixed. The fitting groove 4 on the outer periphery of the enlarged portion 45a
A cutout recess 45c in which the locking piece 49 is disposed is formed at a position opposed to each other at a position displaced by 90 degrees in the circumferential direction with respect to the portion where the 5b is formed. The locking projections 49a of the locking pieces 49 are locked to the step portions 45d at both upper and lower ends in the drawing of the cutout concave portion 45c, so that the arc-shaped member 47 is attached to the enlarged portion 45a.

A spring positioning projection 45e is provided on the mutually opposing surfaces of the locking piece 49 in the notch recess 45c, and a spring 51 as an elastic member positioned by the projection 45e is accommodated in the notch recess 45c. Have been. The spring 51, the locking piece 49, and the arc-shaped member 47 constitute an elastic body.

The spring 51 urges the one arc-shaped member 47 in the direction of separating the arc-shaped members 47 from each other via the locking piece 49, whereby the arc-shaped member 47 is moved to the tool holder 19 shown in FIG. In the hollow groove 25d on the inner surface of the hollow portion 25c, and the tool holder 19 is temporarily held. When the locking piece 49 is pressed by the spring 51 and the locking projection 49a of the locking piece 49 is in contact with the step 45d, the gap between the arc-shaped member 47 and the fitting groove 45b is the same as that of FIG. The elastic ring 41 and the fitting groove 37 in FIG.
A gap similar to the gap 43 is formed between them.

In the example shown in FIGS. 6 and 7, the same operation and effect as those of the first and second embodiments can be obtained, and the pair of arc-shaped members 47 are circularly attached to the tool holder 19. Since the parts opposing each other in the circumferential direction are evenly pressed, the positioning stability at the time of temporary holding is more stable than the one provided with the elastic ring 41 in FIG. 1 or FIG. The performance is further improved.

FIG. 8 shows a fourth embodiment of the present invention. In this embodiment, a sphere 55 made of a steel ball or the like and an inner peripheral surface of the hollow portion 25c of the tool holder 19 are provided on the outer peripheral portion of the expanded portion 53a of the draw bar 53 via a washer-shaped spring receiver 57 on the outer periphery of the expanded portion 53a. As shown in FIG. 9, an elastic body having a spring 59 pressed toward
It is provided at four locations at equal intervals in the circumferential direction.

An elastic body receiving hole 53b for accommodating the elastic body is formed in the outer peripheral portion of the enlarged portion 53a, and a sphere locking piece 61 is press-fitted or screwed into the opening of the elastic body receiving hole 53b. Has been fixed by. A small hole 61a is formed in the center of the spherical locking piece 61, and a spring 59
The sphere 55 pushed by this slightly protrudes from the small hole 61a. The protruding part of the sphere 55 is formed by an annular groove 25 d formed on the inner surface of the hollow part 25 c of the tool holder 19.
As a result, the tool holder 19 is temporarily held on the main shaft 17 side.

In the case of this embodiment, since the set loads of the four springs 59 can be changed, for example, when the main shaft 17 is arranged horizontally, the load of the spring 59 located at the upper part is reduced. By setting it stronger than the spring 59 located at the lower part, the positioning in the temporary holding becomes more stable.

In the examples of FIGS. 8 and 9 described above, if at least three elastic bodies including the sphere 55 and the spring 59 are provided, the positioning during the temporary holding can be stabilized. .

FIG. 10 and FIG. 11 show a fifth embodiment of the present invention. FIG. 10 is a side view around the enlarged portion 63a at the tip of the drawbar 63, and FIG.
It is -B sectional drawing. This embodiment is different from the third embodiment shown in FIG. 6 and FIG.
In this embodiment, two arc-shaped members 65 corresponding to the arc-shaped member 47 in the third embodiment are combined with the sphere 55 in the fourth embodiment. And three spheres 67 are provided.

The arc-shaped member 65 is formed with a through hole 65a whose outer peripheral side is narrowed, and a part of a sphere 67 inserted into the through hole 65a from the inner peripheral side protrudes toward the outer peripheral side. In this state, a screw plug 69 is fastened to a female screw portion formed on the inner surface of the through hole 65a to fix the ball 67. Other configurations are basically the same as those shown in FIGS.

If at least two spheres 67 are provided for one arc-shaped member 65, the positioning stability at the time of temporary holding is ensured.

[Brief description of the drawings]

FIG. 1 is a sectional view of a tip end portion of a main shaft of a machine tool such as a machining center, showing a tool holder mounting device according to a first embodiment of the present invention.

FIG. 2 is a front view of an elastic ring used in the tool holder mounting device of FIG.

FIG. 3 is an enlarged sectional view showing a temporary holding state in a temporary holding section of the tool holder mounting device of FIG. 1;

FIG. 4 is an enlarged cross-sectional view showing a state where the tool holder mounting device of FIG. 1 is not temporarily held in a temporary holding section.

FIG. 5 is a cross-sectional view of a tip end of a main shaft of a machine tool such as a machining center, showing a tool holder mounting device according to a second embodiment of the present invention.

FIG. 6 is a side view of a tip of a drawbar, showing a tool holder mounting device according to a third embodiment of the present invention.

FIG. 7 is a sectional view taken along the line AA of FIG. 6;

FIG. 8 is a cross-sectional view of a tip end of a spindle of a machine tool such as a machining center, showing a tool holder mounting device according to a fourth embodiment of the present invention.

9 is a cross-sectional view showing a temporary holding portion at the tip of the drawbar in FIG. 8, cut along a plane perpendicular to the axis of the main shaft.

FIG. 10 is a side view of a tip of a drawbar, showing a tool holder mounting device according to a fifth embodiment of the present invention.

FIG. 11 is a sectional view taken along line BB of FIG. 10;

FIG. 12 shows a tool holder mounting device according to a conventional example.
FIG. 2 is a cross-sectional view of a spindle tip of a machine tool such as a machining center.

13 is a cross-sectional view showing a state where the tool holder is temporarily held by the tool holder mounting device of FIG.

[Explanation of symbols]

 17 Main shaft 19 Tool holder 21 Taper hole 23 Hollow taper shank 25c Hollow part 29 Collet 31 Drawbar 37, 39 Sleeve 39a, 25d Annular groove (recess, temporary holding part) 41 Elastic ring (elastic body, temporary holding part) 47, 65 Arc-shaped member (elastic body) 49 Locking piece 51,59 Spring (elastic member, elastic body) 55,67 Spherical body (elastic body)

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B23B 31/117 B23Q 3/157

Claims (10)

(57) [Claims] 1. A hollow taper shank of a tool holder inserted into a tapered hole of a main shaft, provided in the tapered hole,
A collet that presses the inner peripheral surface of the hollow taper shank inserted into the tapered hole by moving outward in the radial direction and makes the same outer peripheral surface adhere to the inner surface of the tapered hole, and is located inside the collet and moves toward the main shaft rear side. And a draw bar for moving the collet radially outward by the movement of the tool holder, in the tool holder, continuously from the hollow hole of the hollow taper shank toward the tool holding portion side of the tool holder. Along with the formed hollow portion, an enlarged portion inserted into the hollow portion is provided at the tip of the draw bar, the draw bar moves forward in the main shaft, the enlarged portion is inserted into the hollow portion, and the collet is radially inward. In the position, the temporary holding portion for temporarily holding the tool holder with respect to the main spindle is provided on the outer peripheral surface of the enlarged portion of the draw bar and the hollow taper. Provided between the inner surface of the hollow portion of the tank, the temporary holding portion is provided with a concave portion provided in one of the expanded portion and the hollow portion, and provided in a state in which the movement in the axial direction is regulated by the other. A tool holder mounting device comprising: an elastic body that enters the recess. 2. The tool holder mounting device according to claim 1, wherein the concave portion is an annular groove, and the elastic body is a substantially annular elastic ring partially open. 3. The tool according to claim 2, wherein sleeves are respectively mounted on the inner surface of the hollow portion of the tool holder and the outer peripheral surface of the draw bar, and each sleeve is provided with an annular groove or an elastic ring. Holder mounting device. 4. The elastic body includes a pair of arc-shaped members provided at positions facing each other in a circumferential direction, and an elastic member that presses the pair of arc-shaped members toward a concave portion, wherein the concave portion includes: The tool holder mounting device according to claim 1, wherein the tool holder mounting device is configured by a groove into which the arc-shaped member enters. 5. The elastic body includes a pair of arc-shaped members provided at positions facing each other in a circumferential direction, and a radial direction at at least two positions along a circumferential direction on an outer peripheral surface of each of the arc-shaped members. The tool holder according to claim 1, further comprising: a sphere protruding outwardly; and an elastic member that presses the pair of arc-shaped members toward the concave side to cause the sphere to enter the concave part. Mounting device. 6. At both ends of a pair of arc-shaped members,
The locking piece locked to the tool holder or the drawbar is fixed, and the elastic member is constituted by a spring that presses the arc-shaped member through the locking piece. Tool holder mounting device. 7. An elastic body is provided on an outer peripheral surface of the draw bar, and a spring is arranged between locking pieces provided at ends of the pair of arc members to separate the pair of arc members from each other. 7. The tool holder mounting device according to claim 6, wherein the tool holders are simultaneously pressed in the directions. 8. The tool holder according to claim 1, wherein the elastic body comprises a sphere that enters the recess and a spring that presses the sphere, and these are provided at at least three positions in the circumferential direction. Mounting device. 9. The tool holder mounting device according to claim 5, wherein the recess is formed by an annular groove. 10. With the hollow taper shank of the tool holder inserted into the tapered hole of the main spindle, the collet on the outer peripheral side moves radially outward by the rearward movement of the draw bar provided on the main spindle side, and the tool is moved. When the holder is fixed to the main shaft or when the fixing is released, the enlarged portion of the draw bar tip is formed continuously from the hollow hole of the hollow taper shank toward the tool holding portion side of the tool holder. When inserted into the hollow portion, the elastic body provided in a state where the movement in the axial direction is restricted to one of the concave portion provided in one of the enlarged portion and the hollow portion is provided in the other. And temporarily holding the tool holder with respect to the spindle.