JPH0796435A - Holding tool - Google Patents

Abstract

PURPOSE:To install a holding tool on a spindle in their state where their shaft centers correctly match each other by providing an annular contact member which acts as a contact surface to being the end surface on the side of a shank part in contact with the end surface of the periphery of a tapered hole in the spindle at a position foward the shank part side from a receiving part, in the axial direction of a main body in the state of freely advancing and retreating. CONSTITUTION:In the case of installing a holding tool 5 on the spindle 2 of a workpiece, when a shank part 10 is inserted into the tapered hole 3 of the spindle 2, firstly the contact surface 14 of a contact member 12 makes contact with the end surface 2a of the hole edge of the spindle 2. When a force added to the shank part 10 in the depth direction of the tapered hole 3, while the contact surface 14 keeps contact with the end surface 2a, the contact member 12 relatively moves against a main body 6 to the opposite side of the shank part 10 against against force added thereto, the shank part 10 slightly moves in the depth direction, and its outer peripheral surface is stack to the inner peripheral surface of the tapered hole 3. Consequently, mutual matching of centers of the spindle 2 and the holding tool 5 is carried out in high precision, and machining precision of an article to machined is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a holder for holding a cutting member such as a drill or a workpiece to be processed in a machine tool.

[0002]

2. Description of the Related Art In a conventional holder, a shank portion provided at one end of a main body for mounting on a spindle of a machine tool has a tapered shape corresponding to the tapered hole of the spindle, and the shank portion has a tapered hole. On the other hand, by fitting the former outer peripheral surface and the latter inner peripheral surface so as to be in close contact with each other, the axis line of the main shaft and the axis line of the main body can be attached with high accuracy.

[0003]

In this conventional holder, when a main shaft is rotated for processing, when a large lateral force is applied to the main body, a bend is generated between the shank portion and the main body, and the main shaft is bent. On the other hand, there was a problem that the main body was eccentric and the processing accuracy was lowered.

In order to increase the strength against the lateral force and prevent the runout of the core, when the shank portion is fitted into the taper hole of the main shaft, a collar provided around the main body is attached to the main shaft. A technique has been devised for exactly contacting the end face, but for that purpose, there is a problem that the holder needs to be formed with extremely high working accuracy. Therefore, in order to avoid the problem, a rubber plate is attached to the surface of the collar facing the end surface of the spindle, and when the shank portion enters the taper hole, the rubber plate first contacts the end surface of the spindle. It has been attempted to compress the rubber plate by making the shank portion go deeper so that the outer peripheral surface of the shank portion comes into close contact with the inner peripheral surface of the tapered hole (Japanese Patent Application No. 4-177370).

However, with such a structure, if the rubber plate is crushed within a short period of time when repeatedly attached and detached, there is a problem that the desired core runout preventing effect is lost.

The present invention has been made to solve the above-mentioned problems (technical problems) of the prior art. It can be mounted in a state in which the axis of the machine tool is correctly aligned with the spindle, and machining work can be performed in the mounted state. It is an object of the present invention to provide a holder that can fulfill the function of preventing core runout when it is carried out and, in addition, can exert its effects even after repeated use over a long period of time.

[0007]

In order to achieve the above object, the holder according to the present invention is provided with a holding portion for an object to be held at one end in the axial direction of the main body, and the main body is machined at the other end. A holder provided with a shank portion having a corresponding tapered shape adapted to be fitted into a taper hole provided at an end portion of the main shaft for mounting in a state where an axis line coincides with a main shaft of a machine, A brim-shaped receiving portion is formed on the outer periphery so as to face the end surface of the main shaft, and the shank portion-side end surface is located at a position closer to the shank portion than the receiving portion, and a peripheral edge of the tapered hole in the main shaft. An annular contact member, which is a contact surface for contacting the end surface of, is provided so as to be movable back and forth in the axial direction of the main body, and between the receiving portion and the contact member,
An elastic hydraulic chamber is provided for urging the contact member toward the shank portion to press the contact surface against the end surface of the main shaft.

[0008]

When the shank portion is inserted into the taper hole of the main shaft, the contact surface of the contact member first contacts the end surface of the hole edge of the main shaft. Further, when a force is applied to the shank portion in the direction of the depth of the tapered hole, the contact member is kept in contact with the end face, and the member is opposed to the shank portion against the biasing force applied thereto. While relatively moving with respect to the shank portion, the shank portion slightly moves in the direction of the deep portion, and the outer peripheral surface thereof is in close contact with the inner peripheral surface of the tapered hole. In this state, the core of the main shaft and the core of the holder coincide with each other with high accuracy. Further, even if a large lateral force is applied to the main body of the holder, this member is in the state of a big rod, and the main body is bent with respect to the shank portion to prevent the holder from centering.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, 1 to 4 show a well-known configuration in a machine tool, 1 is a frame, 2 is a rotatable spindle, 3
Indicates a tapered hole for mounting a holding tool, and 4 indicates a pulling tool. Next, the holder 5 will be described in detail with reference to FIGS.
Reference numeral 6 denotes a main body of the holder, which is formed to have a thickness having necessary and sufficient rigidity. Reference numeral 7 denotes a brim-shaped receiving portion that faces the end surface 2a of the main shaft 2, and a mounting portion 7a for a member to be described later is formed on the outer periphery of the main body 6 so as to have a brim-like shape. Here is an example: It may be formed in a brim shape protruding from the outer periphery of the main body 6. Reference numeral 8 denotes a fitting portion of the transmission member formed on a part of the mounting portion 7a. Reference numeral 9 denotes a holding portion of the held object provided at one end of the main body 6, and a cutting tip as an example of the held object.
9a is fixedly held. The holding part may be a cutting member such as a drill or a chuck that detachably holds the workpiece as the held object. Reference numeral 10 denotes a shank portion provided at the other end of the main body 6, the outer peripheral surface of which is formed integrally with the main body 6 in a tapered shape corresponding to the inner peripheral surface of the tapered hole 3.
Reference numeral 11 denotes a pull stud provided at the tip of the shank portion 10.

Next, 12 is a member provided on the outer periphery of the main body 6,
It is formed in an annular shape and extends along the mounting portion 7a along the axis 6a of the main body 6.
It is equipped to move back and forth in any direction. Reference numeral 13 denotes a fitting portion provided on a part of the outer periphery of the corresponding member 12, which is a drive piece provided on the main shaft 2.
It is a part for fitting 2c. Reference numeral 14 is a surface which is in contact with the end surface 2a of the main shaft 2 and is a surface which is divided into a plurality of parts in the circumferential direction in order to keep various members 25, 26 and 27 described later, but it may be formed as a continuous surface. 15 is a fitting portion formed on the inner peripheral surface of the member,
Reference numeral 16 denotes a transmission member for transmitting a rotational force from the member 12 to the main body 6. Reference numeral 18 denotes an elastic hydraulic chamber formed between the receiving portion 7 of the main body 6 and the contact member 12, and the outer peripheral surface of the mounting portion 7a and the receiving portion 7
, A pressure receiving surface 7b facing the shank portion 10, a pressure receiving surface 12b facing the receiving surface 7b of the contact member 12, an outer peripheral wall 19 integrally formed with the contact member 12, and an O-ring 2 for preventing oil leakage.
The oil 20 is filled with an internal space surrounded by 1 and 22 as an example. When the member 12 is moved to the receiving portion 7 side and the oil 20 is pressurized, for example, the O-rings 21 and 22 are pressed and deformed by the oil 20 so that the elastic hydraulic chamber 18 is elastic. Cause The elastic force may be generated by the deformation of part of the member 12. The oil in the hydraulic chamber 18 is initially filled in a large amount, and the member 12 is attached to the receiving portion 7 with a predetermined axis line as shown in FIG. 5 while allowing the oil 20 to flow out from the oil drain hole 26 communicating with the elastic hydraulic chamber 18. The oil drain hole 26 is closed with the stopper 27. 23 is an elastic hydraulic chamber for adjusting the amount of oil in the elastic hydraulic chamber 18
A cylinder provided in a state of communicating with 18, and provided with a piston 24 for adjusting the amount of oil so that the piston 24 can move back and forth. The piston 24 is for adjusting the amount of the oil 20 in the elastic hydraulic chamber 18 so that when the contact surface 14 is in pressure contact with the end surface 2a as shown in FIG. The adjustment is performed by operating the push screw 25 while the holder 5 is not attached to the spindle 2. The cylinder 23 may be provided in the main body 6 so as to communicate with the hydraulic chamber 18. Reference numeral 28 denotes a retaining ring for the member 12.

In the above structure, the holder 5 is attached to the main shaft 2.
When installing the shank part 10, taper hole 3
As shown in Fig. 5, pull stud with pulling tool 4
Pull the shank portion 10 through 11. Then, first, as shown in FIG. 6, the contact surface 14 of the contact member 12 contacts the end surface 2a of the main shaft 2.
At this time, the inner peripheral surface 3a of the tapered hole 3 and the outer peripheral surface of the shank portion 10
A slight gap remains with 10a. When the shank portion 10 further penetrates deeply into the tapered hole 3 by a slight dimension, the outer peripheral surface 10a comes into close contact with the inner peripheral surface 3a as shown in FIG.
The axis 2b of 2 and the axis 6a of the main body 6 coincide with each other. In this case, the abutting member 12 slightly moves toward the receiving portion 7 side with respect to the main body 6 in the abutting state, the oil 20 in the elastic hydraulic chamber 18 is pressurized and the pressure increases, and the abutment 14 Is in a state of being pressed against the end surface 2a with a large pressure. The distance between the pressure receiving surface 7b and the pressure receiving surface 12b may be of a size that allows the slight movement of the contact member 12 as described above.

When the main shaft 2 is rotated in the attached state, the holder 5 is integrally rotated. In this case, the turning force of the main shaft 2 is transmitted from the drive piece 2c to the member 12 via the fitting portion 13, and further to the main body 6 via the transmission member 16. By turning the holder 5, the workpiece W is cut by the tip 9a. In the case of the cutting, even if a large lateral force is applied to the main body 6 of the holder 5 to bend the shank portion 10 against the main body 6 of the holder 5 due to the cutting resistance exerted on the tip 9a, the contact surface 14 is on the outer peripheral side of the shank portion 10. Since it is pressed against the end face 2a at
The main body 6 is given a large resistance against the lateral force, the bend is prevented, and as a result, the runout of the holder main body 6 with respect to the spindle 2 is prevented.

For example, when a force is applied to tilt the axis 6a of the main body 6 in the direction of arrow 31 in FIG.
The oil 20 on the side indicated by reference numeral 18a has a stronger compressive force, and the oil 20 on the side indicated by reference numeral 18b
20 has a weaker compression force. Then, the pressure of the receiving surface 7b in the elastic hydraulic chamber 18a increases, and the pressure of the receiving surface 7b in the elastic hydraulic chamber 18b weakens. As a result, the body 6 receives a force in the direction opposite to the direction of the arrow 31, and the bend is prevented. In the above case, the holder 5 is in the rotating state, and the force for bending is applied to the number of the chips 9a per unit time at the number of rotations of the main shaft 2 (for example, several hundreds to several thousands RPM). It is performed at such a high speed that it is repeated by the number of times. Therefore, even if the elastic hydraulic chamber 18a and the elastic hydraulic chamber 18b are continuous, pressure cannot be transmitted between them (for example, because of the viscosity of the oil 20), and as a result, the arrow 31 Is applied with force in the opposite direction. In order to perform such an action, it is preferable to use the oil having higher viscosity as the number of rotations of the main shaft per unit time is smaller. As a result of the above-described bend prevention, the axis 6a of the main body 6 is kept in a state of being coincident with the axis 2b of the main shaft 2,
The work piece can be cut with high precision.

Next, when there is a margin in the movable size of the contact member 12 with respect to the axial direction of the main body 6, the right angle accuracy of the end face 2a of the main shaft 2 is low, or as shown in FIG. Even if the member 12 is tilted when the holder 5 is attached to the main shaft 2 by catching dust 32 with the contact surface 14, the oil 20 remains in the elastic hydraulic chamber in that state.
Since the pressure is constant in the entire 18, the bend preventing action as described above is performed without any difference.

Next, FIG. 8 shows a different embodiment of the present invention, and shows an example in which a metal spring is provided between the receiving portion 7e and the member 12e as a means for applying a biasing force. An example of the metal spring is a disc spring 33, which is interposed between the receiving surface 7be and the pressure receiving surface 12be. In addition, parts that are considered to be the same or equivalent in configuration to those in the previous figure in terms of function are denoted by the same reference numerals as those in the previous figure with the letter e added to omit redundant description.

[0016]

As described above, according to the present invention, when the holder 5 is attached to the spindle 2 of the machine tool, when the shank portion 10 is inserted into the taper hole 3 of the spindle 2, first the contact surface of the contact member 12 is reached. 14
Comes into contact with the end surface 2a of the hole edge of the main shaft 2 and further a force is applied to the shank portion 10 in the direction of the depth of the tapered hole 3,
While the contact surface 14 is in contact with 2a, the contact member 12 moves relative to the main body 6 on the side opposite to the shank portion 10 against the biasing force applied thereto, while the shank portion 10 is deeper than the deep portion. It has a feature that it moves slightly in the direction, and its outer peripheral surface 10a comes into close contact with the inner peripheral surface 3a of the tapered hole 3. As a result, the cores of the main shaft 2 and the holder 5 are accurately aligned,
It has the effect of improving the processing accuracy of the work piece,
Even if a large lateral force is applied during the machining operation, there is an effect that the center runout of the tool holder 5 with respect to the spindle 2 can be prevented and highly accurate machining can be performed.

Moreover, the urging force of the contact member 12 is due to the elastic hydraulic chamber.
Since it has a highly durable structure of 18 or metal spring 33, even if the holder 5 is repeatedly attached to and detached from the main shaft 2, the function of urging the member 12 can be retained, and as a result, long-term There is an advantage that the above-mentioned core runout preventing effect can be surely exhibited over the use of.

[Brief description of drawings]

FIG. 1 is a side view showing a usage state.

FIG. 2 is an enlarged cross-sectional view of a main part in FIG.

FIG. 3 is a view showing a state where the holder is viewed from the shank portion side.

FIG. 4 is a sectional view taken along line IV-IV in FIG.

FIG. 5 is a view similar to FIG. 2 showing a state before attachment to the spindle.

FIG. 6 is a view similar to FIG. 2 showing a state during mounting on the spindle.

FIG. 7 is an enlarged sectional view of an essential part showing an example in which the usage state is different.

FIG. 8 is an enlarged cross-sectional view of a main part showing a different embodiment.

[Explanation of symbols]

 6 Main body 7 Receiving part 9 Holding part 10 Shank part 12 This member 18 Elastic hydraulic chamber 33 Metal spring

Claims (2)

[Claims] 1. A main body is provided with a holding portion for an object to be held at one end in the axial direction, and the other end is provided at the other end for attaching the main body in a state where the main shaft of the machine tool is aligned with the axis. In a holder provided with a shank portion having a corresponding taper shape adapted to be fitted in a taper hole provided in the portion, a brim-shaped receiving portion facing the end face of the main shaft is formed on the outer periphery of the main body. At the same time, at a position on the shank portion side of the receiving portion, an annular contact member whose end surface on the shank portion side is an abutting surface for abutting the end surface of the peripheral edge of the tapered hole in the spindle, An elastic hydraulic pressure is provided between the receiving portion and the abutting member so as to urge the abutting member toward the shank portion so that the abutting surface is pressed against the end surface of the main shaft. A holder provided with a chamber. 2. A main body is provided with a holding portion for an object to be held at one end in the axial direction, and the other end is provided at the other end for attaching the main body in a state where the main body is aligned with the main shaft of the machine tool. In a holder provided with a shank portion having a corresponding taper shape adapted to be fitted in a taper hole provided in the portion, a brim-shaped receiving portion facing the end face of the main shaft is formed on the outer periphery of the main body. At the same time, at a position on the shank portion side of the receiving portion, an annular contact member whose end surface on the shank portion side is an abutting surface for abutting the end surface of the peripheral edge of the tapered hole in the spindle, A metal spring which is provided so as to be movable back and forth in the axial direction of the main body, and between the receiving portion and the contact member, the contact member is urged toward the shank portion to press the contact surface against the end surface of the spindle. A holder characterized by being provided with.