JP2001252841A - Tool holder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To from a hollow part having a thickness as thin as achieving a required bending resistance strength at each periphery at an inside of a grasping tool engaging part, at an inside of a tool holding part positioned at an end thereof and an inside of a shank part positioned at another end thereof, and to reduce a whole weight. SOLUTION: This tool holder is provided with a tool holding part at an end, a shank part at another end, and a grasping tool engaging part at an intermediate part. A thickness as thin as achieving a required bending resistance strength at each periphery is formed at an inside of the grasping engaging part, an inside of the tool holding part and an inside of the shank part to form a large hollow part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a milling machine, a drill,
The present invention relates to a tool holder for attaching various other cutting blades to a main shaft of a machine tool.

[0002]

2. Description of the Related Art A tool holder 5 shown in FIG. 3 is an example of a conventionally widely known tool holder (see, for example, Japanese Patent Application Laid-Open No. Hei 5-337768). Therefore, a conventional example will be described with reference to FIG. Reference numerals 1 to 4 denote the structure of a known machine tool. Reference numeral 1 denotes a frame, 2 denotes a rotatable main shaft, 3 denotes a tapered hole provided at the front end of the main shaft, and 4 denotes a pulling tool. Next, 5 shows a main body of the tool holder. In this example, a tool holder provided with a mounting portion (shank portion 8) for the main shaft is shown. Reference numeral 6 denotes a tool holding portion of the tool holding tool. Reference numeral 7 denotes a cutting blade holder for cutting a workpiece W provided at the front end of the tool holding unit in the main body 5, and for example, a plurality of, for example, three cutting blades 7d are provided around the front end. Reference numeral 8 denotes a shank provided at the rear end of the main body 5, and the outer periphery is formed in a tapered shape corresponding to the tapered hole 3. 9 is a shank portion provided at the rear end of the main body 5
Shows a pull stud attached in an embedded manner. Reference numeral 10 denotes a flange portion provided on the outer periphery of the main body 5, which is a portion to be gripped by a gripper of a tool changer (not shown), and has a groove 11 for gripper fitting for use as a gripper fitting portion. Have. The flange portion 10 is provided at a position where a gap can be formed between the rear surface 16 and the front end surface 15 of the main shaft 2, and a gap for interposing a vibration isolator as is generally known is provided in the gap. It has become. A concave fitting portion 12 is formed in a part of the flange portion 10 so that a driving piece on the machine tool side can be fitted to the fitting portion 12 as is well known.

[0003]

In the conventional tool holder, the outer shape is naturally large due to the thickness of the front end of the main shaft 2, the shape of the taper 3 provided therein, and the shape of the cutting blade holder 7. Become something. Therefore, its own weight is heavy, and when the tool holder 5 is quickly replaced during the operation due to the convenience of the operation, when the tool holder is to be gripped by the gripper of the tool changer (not shown), the tool holder is held by the tool holder. If the weight of the tool is heavy, it often falls off. Note that even in a configuration in which a cooling liquid passage hole is provided in the center of the tool holder or an operation hole for operating an internal adjustment member in the tool holder, the weight of the tool does not change much. Accident prevention effect cannot be expected. Also, if the weight of the tool holder is heavy, and it is attached to the front end of the spindle 2 and rotated at high speed, even if there is a slight deviation in the adjustment of the rotational balance, if the weight of the holder is heavy, its inertia will be high. As a result, there is also a problem that the runout of the core is caused and the machining accuracy is remarkably reduced.

[0004] The tool holder of the present application is provided to solve the above-mentioned problems of the prior art. The purpose of the present application is to provide a thin wall thickness enough to provide bending resistance on the outer periphery of the inside of the gripper fitting portion, the inside of the tool holding portion located on both sides thereof, and the inside of the shank portion. An object of the present invention is to provide a tool holder in which a large hollow portion is formed while leaving it, and the overall weight is reduced. Another object is to form the shank portion and the tool holding portion separately from each other, form a hollow portion for each, and combine them to form a large hollow portion for weight reduction in the main body of the tool holder. An object of the present invention is to provide a tool holder that can be formed. Another object of the present invention is to provide a tool for joining the edges of both openings of the shank portion and the tool holding portion by means for preventing unexpected bending stress from concentrating on the joint portion of the two. It is intended to provide a holder. Another object is to form the tool holder with a shank portion and a tool holder having a different material property from the shank portion, thereby widening the natural frequency of the tool holder during high-speed rotation to reduce the center runout. An object of the present invention is to provide a tool holder in which a decrease in cutting accuracy is prevented in advance. Other objects and advantages will be more readily apparent from the drawings and the following description associated therewith.

[0005]

According to the present invention, there is provided a tool holder provided with a tool holder at one end in an axial direction of a main body.
The other end in the axial direction of the main body is provided with a corresponding tapered shank portion adapted to fit the main body into a tapered hole provided in the main shaft of the machine tool, and a gripper fitting portion is provided at an intermediate portion. In the tool holder, the inside of the gripping tool fitting portion, the inside of the tool holding portion on one side, and the inside of the shank portion on the other side have bending strength on the outer periphery, respectively. In this case, a large hollow portion is formed while leaving a small wall thickness enough to obtain a weight reduction. In the tool holder, the shank portion and the tool holding portion are formed separately from each other,
The inside of the shank portion is formed in a hollow shape with an opening on the side of the tool holding portion, and the gripping tool fitting portion is provided around the opening, while the inside of the tool holding portion is Is formed to be hollow with an opening on the side of the shank, and both the shank and the tool holder are integrated with the edges of both openings being joined together. Further, the means for joining the edges of both openings of the shank portion and the tool holding portion is joined by friction welding. Furthermore, by making the properties of the material of the shank and the tool holder different from each other, the natural frequency of the shank and the tool holder at the time of high-speed rotation is made different, thereby reducing the runout of the tool holder. It is like that.

[0006]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention. In FIGS. 1 and 2, the functions, properties, characteristics, and the like of the components and members and the like denoted by the same reference numerals as those in FIG. 3 described above are the same as those described above except for new members, configurations, combinations, and the like described below. Therefore, a duplicate description will be omitted.

The tool 5 has a tool holding portion 6 at one end in the axial direction thereof, and the tool 5 is fitted into the tapered hole 3 provided in the main shaft 2 of the machine tool at the other end of the tool 5 in the axial direction. A tool holder having a corresponding tapered shank portion 8 to be held, and a gripper fitting portion 10 provided around the middle portion is shown.

A cutting blade holder 7 for attaching a cutting blade 7d for cutting, such as a milling cutter, to the main shaft 2 of the machine tool via a tool holder 5 at the tips 6c and 6d of the tool holding unit 6, or A cutting blade holder such as a chuck capable of detachably mounting an arbitrary cutting tool such as a drill is mounted and used. The receiving surface 6c and the convex portion 6d of the holding portion 6 are connected to the inner surface of the contact surface 7b and the inner periphery of the concave portion 7a of the holder 7 so as to be separated and replaceable (replaceable with a drill chuck or the like), respectively. It is integrated. Reference numeral 7e denotes a bolt inserted into the hole 7c, which fastens the holding portion 6 and the holder 7 by screwing into a female screw hole 6g provided in the projection 6d. At the rear part of the holding part 6, an opening 6 of a hollow 6b for weight reduction formed inside is provided.
a is provided. The thickness of the outer peripheral structure 6f of the hollow portion 6b is adjusted to the thickness of the flange 10, but it may be formed as thin as possible within a range where a predetermined bending strength can be obtained. The front wall 6g of the hollow portion 6b may be formed separately from the structure 6f at a position indicated by a dashed line in FIG.

The peripheral wall 8b of the shank portion 8 is formed with a hollow 8c on the inside in order to reduce the diameter and reduce the weight as described later. The thickness of the peripheral wall 8b of the shank portion 8 is, for example, about 10% of the diameter of the maximum diameter portion of the shank portion 8 in order to obtain bending resistance and to have necessary and sufficient rigidity against bending. In addition, it is preferable that the thickness of the shank 8 is uniform throughout the circumferential direction in order to prevent displacement of the shaft when the shank 8 is reduced in diameter. A flange 10 is formed on the outer periphery of the opening 8d of the hollow portion 8c of the shank 8 so that the thickness is further increased to reinforce the front side of the shank 8.
(The inside is a hollow portion 10a). Further, the front end face 8e thereof and the rear end face 6e of the opening 6a in the holding portion 6 are formed.
Means that they are integrally joined by a joining means by friction welding. The flange 10 is formed with a gripper fitting portion 10 having a well-known concave groove 11.

The positions of the joints 8e and 6e are such that the gripper fitting portion 10 is in the middle, the inside 10a thereof, the inside 6b of the tool holding portion 6 on one side, and the shank on the other side. The inside 8c of the portion 8 is connected to the cylindrical structural portions 6f, 10f, 10 having a thickness small enough to provide bending resistance on the outer periphery.
b and 8b are formed in a large hollow portion for reducing the weight, and the whole is reduced in weight, so that the weight balance relating to the volume of the hollow portion on the left side 8c and the hollow portion on the right side 6d when viewed from the position of the fitting portion 10. It is preferable that the entirety of the tool holder 5 be made lighter in a state where the values are uniformly taken.

Further, the materials of the shank portion 8 and the tool holding portion 6 may be completely the same or different. If the same material is used, the cylindrical member (8
b, 6f), or by using different materials, for example, materials having different specific gravities, to make the natural frequencies of the two at high speed rotation different from each other. It is preferable to reduce the natural vibration of the motor to prevent the runout of the core during high-speed rotation.

The specific gravity of the constituent material is exemplified below. In using the shank portion 8 and the tool holding portion 6 as materials, it is preferable to use different materials among them. Mechanical structural steel: specific gravity of about 7.8, stainless steel: specific gravity of about 7.6, titanium alloy: specific gravity of about 4.5, aluminum alloy: specific gravity of about 2.7.

In the above configuration, the tool holder 5 is attached to the main shaft 2 so that the tool holder 5 can be mounted on the machine tool for use.
When mounting, as is well known, the shank portion 8 is
The shank portion 8 is pulled in through the pull stud 9 screwed into the female screw hole 8f of the shank portion 8 with the pulling tool 4. Then, first, the outer peripheral surface 8a of the shank portion 8 contacts the inner peripheral surface of the tapered hole 3 as shown in FIG. Further, when the shank portion 8 is pulled toward the deep portion of the tapered hole 3, the shank portion 8 is slightly guided toward the deep portion of the tapered hole 3 while being guided by the inner peripheral surface thereof to reduce the diameter of the shank portion 8. And
It will be in a predetermined mounting state. In the attached state, the shank 8
The axis of the main shaft 2 and the axis of the main body 5 accurately coincide with each other due to the close contact between the outer peripheral surface 8a and the inner peripheral surface of the tapered hole 3.

[0014]

As described above, according to the present invention, the inner side of the gripper fitting portion 10, the inner side of the tool holding portion 6, and the inner side of the shank portion 8 are of such a degree that bending resistance can be obtained on the outer periphery. Since the large hollow portions 10a, 6b, 8c are formed while leaving a small thickness, the overall weight of the tool holder 5 becomes extremely light, and when the tool holder is replaced during the cutting operation, the tool changer is required. The burden on the gripper is reduced, and there is an effect that the accident that the tool holder falls off from the gripper of the tool changer is significantly reduced.

Even if a hollow portion for reducing the weight is formed inside the tool holder 5, the inside of the separately formed tool holding portion 6 is previously formed in the hollow 6b, and the inside of the separate shank portion is formed. Are also formed in the hollow 8c, and both of them
Since the edges of d and 6a are integrated in a state where they are joined together, the construction method has an effect of being extremely simplified. Moreover, when the edges 8e and 6e of both openings are joined together,
In the case where the friction welding means is used, the joining of the two becomes extremely smooth, and there is an effect that the stress is prevented from being concentrated on the joining portion and the life can be extended.

In addition, since the shank portion 8 and the tool holding portion 6 are formed separately from each other, different materials having different natural frequencies can be used for these two materials. There are features. Thereby, there is an effect that the center runout of the tool holder 5 at the time of high-speed rotation can be made extremely small. Moreover, since the inside of the main body 5 of the tool holder is hollow as described above, the weight is lighter than that of the solid body, and the burden on the spindle 2 during rotation is reduced.
From this point as well, an excellent effect of preventing runout of the core during high-speed rotation is exhibited.

[Brief description of the drawings]

FIG. 1 is a partially cutaway view of a shank portion and a tool holding portion formed separately.

FIG. 2 is a partially broken view showing a state in which a tool holder is mounted on a main shaft of a machine tool.

FIG. 3 is a partially cutaway view showing a state in which a conventional tool holder is mounted on a main shaft of a machine tool.

[Explanation of symbols]

2 ... spindle, 3 ... tapered hole, 5 ... tool holder, 6 ... tool holder, 6a ... opening, 6b ...
· Hollow part, 6f · · · outer peripheral structure, 7 · · · cutting blade holder, 8 · · · shank part, 8a · · · outer peripheral surface, 8b · · · ·
・ Peripheral wall, 8c: hollow part, 8d: opening part, 10 ・
..Grip fitting part.

Claims (4)

[Claims] 1. A tool holding part is provided at one end in the axial direction of a main body, and the main body is fitted into a tapered hole provided in a main shaft of a machine tool at the other end in the axial direction of the main body. In the tool holder provided with a tapered shank portion, the intermediate portion is provided with a gripper fitting portion, inside the gripper fitting portion, inside the tool holding portion on one side, A tool holder characterized in that a large hollow portion is formed on the inside of the shank portion on the other side, leaving a small thickness on the outer periphery so that bending resistance can be obtained, thereby reducing the weight. . 2. A tool holding part is provided at one end in the axial direction of the main body, and the other end in the axial direction of the main body is adapted to fit the main body into a tapered hole provided in a main shaft of a machine tool. In a tool holder having a tapered shank portion and a gripper fitting portion in an intermediate portion, the shank portion and the tool holding portion are formed separately from each other, and the inside of the shank portion is a tool. While being formed in a hollow state with an opening on the side of the holding portion, the gripper fitting portion is provided around the opening thereof, while the inside of the tool holding portion is on the side of the shank portion. A tool holder characterized in that it is formed hollow with an opening, and both a shank portion and a tool holding portion are integrated so that edges of both openings are joined together. 3. The tool holder according to claim 2, wherein the means for joining the edges of both the openings of the shank portion and the tool holding portion is joined by friction welding. 4. The center runout of the tool holder can be reduced by changing the natural frequency of the shank and the tool holder during high-speed rotation by making the material properties of the shank and the tool holder different from each other. 4. The tool holder according to claim 2, wherein the tool holder is reduced.