JPH0919801A - Tool holder - Google Patents

Abstract

(57) [PROBLEMS] To obtain a tool holder having a long tool life in which the radial position of a cutting tool can be adjusted. An eccentric shaft 18 includes a tip portion 28 that is eccentric from a center line L, and an adapter 13 is fitted to the tip portion 28 via a piece 36. The tip portion 28 and the piece 36 are fitted to each other via a rolling bearing 40, and the piece 36 is attached to the linear bearing 4 on the adapter 13 at both side surfaces 45 and 46.
It is fitted via 8, 49. When the eccentric shaft 18 is rotated about the center line L, the tip end portion 28 is revolved about the center line L, the adapter 13 is moved in the diameter direction, and the position of the cutting tool in the radial direction is changed. The rolling bearing 40 and the linear bearings 48, 49 prevent the eccentric shaft 18, the piece 36, and the adapter 13 from being worn and improve the durability. By setting the rolling bearing 40 and the linear bearings 48 and 49 to negative clearances, the processing accuracy can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tool holder capable of adjusting a radial position of a cutting tool with respect to a holder body.

[0002]

2. Description of the Related Art Conventionally, there has been known a tool holder capable of adjusting a radial position of a cutting tool with respect to a holder body. As an example thereof, there is a tool holder shown in FIG. In this tool holder, a central shaft 301 slidably fitted in the holder main body 300 in the axial direction is provided with a first engaging protrusion provided on the outer peripheral surface of the tip portion 302 so as to be inclined with respect to the central line A. It has a portion 304 and a second engagement protrusion 308 that is provided on the outer peripheral surface of the intermediate portion 306 so as to be inclined with respect to the center line A in the direction opposite to the first engagement protrusion 304. A moving member 310 having a tool attachment portion and movably held in the holder main body 300 in the diametrical direction is engaged with the tip portion 302,
A balancer 312, which is movably held in the holder main body 300 in the diametrical direction, is engaged with the intermediate portion 306. The moving member 310 includes the first engaging protrusion 3 of the tip portion 302.
The balancer 3 has an engaging concave portion (not shown) that engages with 04.
Similarly, 12 also has an engagement recess (not shown) that engages with the second engagement protrusion 308.

Therefore, when the central shaft 301 is moved in the axial direction, the moving member 310 is moved in the diametrical direction of the holder main body 300, and the balancer 312 is also in the diametrical direction of the holder main body 300 with respect to the central line of the moving member 310. It is moved in the opposite direction to A. Moving member 310
The cutting tool is moved in the radial direction along with the diametrical movement of the cutting tool. Further, since the moving member 310 and the balancer 312 are moved in the opposite directions to each other with respect to the center line A, even if the position of the cutting tool in the radial direction changes, the balance of the entire tool holder is maintained, or the balance is maintained. The decrease is suppressed. Therefore, even when the cutting tool is rotated at a high speed to process the work piece, it is possible to suppress a decrease in the working accuracy of the work piece.

[0004]

However, when manufacturing the above tool holder, there is a problem that high machining accuracy is required. Moving member 310 and balancer 312
As described above, the holder main body 300 is movably held in the diametrical direction, and the engaging concave portions that engage with the first and second engaging protrusions 304 and 308 of the central shaft 301 are formed. However, in that case, the clearance between the fitting portions must be made small, and the inclination angles of the engaging recesses and the first and second engaging protrusions 304, 308 must be accurately matched. .

A holder body 300 of the first and second engaging projections 304, 308, the moving member 310 and the balancer 312.
When the clearance between the fitting portion with respect to the central shaft 301 is large, the rattling of the moving member 310 and the balancer 312 with respect to the holder main body 300 and the central shaft 301 becomes large,
In addition to causing vibration, the positioning accuracy of the cutting tool in the radial direction decreases, and the processing accuracy of the work piece decreases. If the clearance is reduced, the inclination angle of each engaging recess and the first and second engaging protrusions 3
The moving member 310 and the balancer 312 cannot be moved with respect to the holder body 300 and the central axis 301 unless the inclination angles of 04 and 306 are accurately matched.

In order to solve the above problem, as described above, the cutting tool is not moved in the radial direction by moving the central axis in the axial direction, but is rotated in the radial direction by rotating the eccentric shaft. We have developed a tool holder that can be moved to. This eccentric shaft type tool holder with a balancer includes (1) a holder body, and (2) a holder body that is rotatably held around a first axis and has a second eccentric axis that is eccentric from the first axis. And an eccentric shaft having a second eccentric shaft portion eccentrically provided on the side opposite to the second axis with respect to the first axis, and (3) relatively rotatable and relative to the first eccentric shaft portion. A moving member having a fitting groove that movably fits and a tool mounting portion to which a cutting tool is mounted, and (4) the moving member is opposed to the end surface of the holder body in a direction substantially orthogonal to the fitting groove. A mounting device that is movably mounted, and (5) a balancer that is movably engaged with the second eccentric shaft portion in a direction parallel to the moving direction of the moving member.

In this tool holder, when the eccentric shaft is rotated about the first axis, the first eccentric shaft portion is revolved about the first axis while rotating about the second axis. Accordingly, the moving member is moved in a direction substantially orthogonal to the fitting groove, and the balancer is moved to the side opposite to the moving member. Along with the movement of the moving member, the cutting tool attached to the tool attachment portion is moved in the radial direction of the holder body.

That is, in the present tool holder, since the moving member is moved in the diametrical direction by the rotation of the eccentric shaft, the machining accuracy as high as that of the conventional tool holder is not required. Further, since the balancer is moved to the side opposite to the moving member, even if the cutting tool is moved in the radial direction,
A decrease in the balance of the entire tool holder is suppressed or prevented. Therefore, even when the cutting tool is rotated at a high speed to perform processing on the workpiece, deterioration of the processing accuracy of the workpiece is suppressed.

However, the tool holder has a problem that the moving member is in linear contact with the eccentric shaft in the fitting groove, and is easily worn, and the machining accuracy is lowered, so that the life of the moving member and the eccentric shaft is short. It was This problem is a problem that generally occurs in an eccentric shaft type tool holder regardless of the presence or absence of a balancer. A balancer is not required when processing a workpiece without rotating the cutting tool, and even if the cutting tool is rotated, the balancer can be omitted if the rotation speed is low. Since a holder is also used, the problem of insufficient service life similarly occurs in this type of eccentric shaft type tool holder.

Therefore, the first invention has been made in order to prolong the life of the moving member and the eccentric shaft in the eccentric shaft type tool holder. An object of the second invention is to improve the machining accuracy of the tool holder according to the first invention. An object of the third invention is to satisfactorily avoid vibration generation during rotation of the tool holder according to the first invention and the second invention.

[0011]

[Means for Solving the Problems] The gist of the first invention is that a tool holder is (1) a holder main body, and (2) is rotatably held by the holder main body around a first axis, An eccentric shaft having a first eccentric shaft portion having an eccentric second axis and a second eccentric shaft portion eccentrically provided on the side opposite to the second axis with respect to the first axis; and (3) eccentricity A piece fitted to the shaft portion so as to be relatively rotatable in the fitting hole and having two side surfaces extending parallel to a straight line perpendicular to the second axis, and (4) fitting so as to be relatively movable with the two side surfaces of the piece. A moving member having a fitting groove for fitting and a tool mounting portion to which a cutting tool is mounted,
(5) An attachment device for attaching the moving member to the end surface of the holder body so as to be relatively movable in a direction substantially orthogonal to the fitting groove.

The piece may have any shape as long as it has two side surfaces fitted into the fitting groove, and if it has a rectangular parallelepiped shape, it has a shape with a curved surface portion. May be made. Further, the fitting groove of the moving member that fits the two side surfaces of the piece includes a recess. This is because the recess can be regarded as having both ends of the groove closed.

The gist of the second invention is that the rolling bearing is arranged with a negative clearance between at least one of the two side surfaces of the piece and the fitting groove of the moving member between the eccentric shaft portion and the fitting hole of the piece. is there. The rolling bearing may be provided only between the eccentric shaft portion and the piece, only between the piece and the moving member, or both of them.

Further, the gist of the third invention is that the eccentric shaft is axially separated from the first eccentric shaft portion which is the eccentric shaft portion,
The second eccentric shaft portion is provided eccentrically to the side opposite to the first eccentric shaft portion with respect to the first axis, and the second eccentric shaft portion is parallel to the moving direction of the moving member on the holder body. The balancer movably held in the direction is engaged in the engagement groove extending in the direction perpendicular to the moving direction of the balancer and the first axis. In other words, when the cutting tool is rotated at a high speed to process the work piece, even if the cutting tool is moved in the radial direction, the balance of the tool holder as a whole is suppressed or prevented from deteriorating. Since the balancer that moves in the opposite direction is provided, it can be said that the piece according to the first invention is added to the above-described eccentric shaft type tool holder with a balancer, from a different viewpoint.

[0015]

In the tool holder of the first aspect of the invention, when the eccentric shaft is rotated about the first axis, the eccentric shaft portion is rotated about the second axis and is revolved about the first axis. Along with this, the piece is moved along the fitting groove, and together with the piece, the moving member is moved in a direction orthogonal to the fitting groove, that is, in a direction in which the mounting device allows the movement. The position of the cutting tool attached to the tool attaching portion in the radial direction changes as the moving member moves.

In this tool holder, since the piece engages with the fitting groove of the moving member on the two side surfaces, the fitting groove and the piece are less likely to wear. In the conventional tool holder, the eccentric shaft and the moving member slipped while making a line contact with each other, and were easily worn.However, in the present tool holder, a piece is arranged between the eccentric shaft and the moving member. Since the and the moving member are engaged with each other on their surfaces, they are hard to wear. Further, even between the eccentric shaft and the piece, the outer peripheral surface of the eccentric shaft and the inner peripheral surface of the fitting hole of the piece are engaged with each other, so that they are less likely to wear and the life is extended.

In the tool holder of the second invention, rolling bearings are provided between the eccentric shaft portion and the moving member and between at least one of the two side surfaces of the piece and the moving member, and a negative clearance is provided between them. It Therefore, rattling in at least one of these is substantially eliminated, and the positioning accuracy in the diametrical direction of the moving member is improved. Further, the provision of the rolling bearing makes it more difficult for the engaging portion to wear, and extends the service life.

In the tool holder of the third invention, the eccentric shaft is provided with a second eccentric shaft portion eccentric to the side opposite to the first eccentric shaft portion at a position axially separated from the first eccentric shaft portion. A balancer is engaged with the second eccentric shaft portion. for that reason,
With the rotation of the eccentric shaft, even if the moving member and the balancer are moved in mutually opposite directions and the cutting tool is moved in the radial direction, deterioration of the balance of the entire tool holder is suppressed.

The balancer is held by the tool holder so as to be movable in a direction parallel to the moving direction of the moving member, and the moving member provided on the balancer itself is moved by the second eccentric shaft portion of the eccentric shaft. The engagement groove extends in a direction orthogonal to the direction and the first axis. Therefore, the balancer can be easily engaged with the eccentric shaft.

[0020]

According to the first aspect of the present invention, the piece is disposed between the moving member and the eccentric shaft, and the eccentric shaft and the piece, and the piece and the moving member are engaged with each other, so that they are worn. It is difficult to do so, and the effect of extending the life is obtained. In the second invention, rattling of at least one of the eccentric shaft and the piece, and at least one of the piece and the moving member is reduced. Therefore, in addition to the effect of the first invention, the positioning accuracy in the radial direction of the cutting tool is increased. And the processing accuracy of the workpiece is improved. In addition, the rolling bearing makes it more difficult for the engaging portion of each member to wear, and thus the life is further extended. In the tool holder of the third invention, even if the cutting tool is moved in the radial direction, deterioration of the balance of the entire tool holder is suppressed or prevented. Therefore, in addition to the effects of the first invention,
Even when the cutting tool is rotated at a high speed to process the workpiece, it is possible to suppress or prevent a decrease in the processing accuracy of the workpiece.

[0021]

Supplementary Explanation of the Invention The present invention is, in addition to the embodiments described in the claims,
It can also be implemented in the modes listed below. (1) The rolling bearing is provided both between the eccentric shaft portion and the fitting hole of the piece and between the two side surfaces of the piece and the fitting groove of the moving member. Tool holder described in. By providing a negative clearance both between the eccentric shaft and the piece and between the piece and the moving member, it is possible to eliminate rattling between these and to improve the processing accuracy of the workpiece. it can. Moreover, the durability can be further improved. (2) The tool holder according to claim 3 or aspect 1, wherein the first eccentric shaft portion is formed at a tip end portion of the eccentric shaft, and the second eccentric shaft portion is formed at an intermediate portion. (3) Furthermore, a tool part holding material detachably attached to the tool attachment part of the moving member is included, and the tool part holding material is substantially the radial direction of the cutting tool from the first axis and substantially the fitting. 4. A tool holding part for holding the dowel groove in a direction perpendicular to the longitudinal direction thereof.
The tool holder described in any one of 1. Although it is possible to directly attach the cutting tool to the tool attachment portion of the moving member, in this aspect, a tool portion holding material including a tool holding portion that holds the cutting tool is attached. Since the tool holding material is removable, it is easy to replace the cutting tool. The direction perpendicular to the longitudinal direction of the fitting groove is the moving direction of the moving member. In this aspect, in the state where the tool holding member is attached to the tool attaching portion, the cutting tool is held in the tool holding portion in a direction that is a radial direction from the first axis and is parallel to the moving direction of the moving member. It will be. If the cutting tool is held in a direction parallel to the longitudinal direction of the fitting groove, that is, in a direction orthogonal to the moving direction of the moving member, even if the moving member moves in the diametrical direction, the first axis of the cutting tool The distance from is almost unchanged. Therefore, it is desirable to hold the cutting tool and increase the amount of change in the distance from the first axis of the cutting tool as in the present embodiment. (4) The tool holder according to any one of claims 1 to 3 and modes 1 to 3, wherein the eccentric shaft is rotatably held by the holder body via a bearing having a negative clearance. The rattling of the eccentric shaft with respect to the holder body can be reduced, and the processing accuracy can be improved. (5) The tool holder according to any one of claims 1 to 3 and 1 to 4, wherein the eccentric shaft is rotated by a ball screw device. A ball screw device is a device that converts linear motion into rotational motion. The eccentric shaft can be rotated by moving the axial moving shaft of the ball screw device in the axial direction. The amount of rotation of the eccentric shaft can be adjusted by adjusting the amount of axial movement of the axial moving shaft, and the amount of diametrical movement of the moving member can be adjusted. (6) The eccentric shaft is further axially located at a position opposite to the first eccentric shaft portion with respect to the second eccentric shaft portion, and toward the opposite side of the second eccentric shaft portion with respect to the first axis. The third eccentric shaft portion is provided in an eccentric state, and a balancer movable to the holder main body in a direction parallel to the moving direction of the moving member is held on the third eccentric shaft portion. The tool holder according to any one of 5. In the tool holder according to claim 3, the mass of the balancer held on the second eccentric shaft portion, the amount of eccentricity (distance of the center line of the second eccentric shaft portion from the first axis line), the moving member, the cutting tool, etc. By properly selecting the mass and eccentricity (distance between the first axis and the second axis), etc., the static balance of the entire tool holder should be maintained even if the cutting tool is moved in the radial direction. Is possible. The center of gravity of the entire tool holder that is a rotating body can always be on the first axis that is the rotating shaft. However, even if the static balance of the tool holder is maintained, a moment (unbalanced moment) around the axis perpendicular to the first axis may occur during rotation due to centrifugal force. On the other hand, the tool holder of this aspect includes the third eccentric shaft portion, and the balancer is held by the third eccentric shaft portion. Therefore, in the tool holder of this aspect, in addition to the above requirements, the mass and eccentricity of the balancer held on the third eccentric shaft portion (distance from the first axis of the center line of the third eccentric shaft portion), If the relative positions in the axial direction of the first eccentric shaft portion, the second eccentric shaft portion and the third eccentric shaft portion are appropriately set,
Even if the cutting tool is moved in the radial direction, it is possible to avoid the occurrence of an unbalanced moment. Even if the cutting tool is moved in the radial direction, it is possible to maintain the dynamic balance of the entire tool holder, and as a result, the machining accuracy can be further improved.

[0022]

DETAILED DESCRIPTION OF THE INVENTION A tool holder, which is an embodiment common to the first to third inventions, will be described in detail below with reference to the drawings. In FIG. 1, the tool holder is fitted to a spindle (not shown) at a fitting portion 12 at the rear end (right end in the drawing) of the holder body 10 and fixed by an appropriate fixing means such as a bolt. Tip of holder body 10 (left edge in the figure)
An adapter 13 is attached to the tool mounting portion 14, and the adapter 13 includes a tool mounting portion 14.
A tool holding member (not shown) is detachably attached to the unit 4. The tool part holding member includes a cutting tool holding part that holds a cutting tool. With the rotation of the main shaft, the holder body 10 and the adapter 13 are rotated, and the adapter 13
The cutting tool attached to the workpiece via the tool holding member is also rotated, so that the workpiece (not shown) is subjected to boring.

Through holes 16 are formed in the holder body 10 along the center line L as the first axis, and the through holes 16 are formed.
The eccentric shaft 18 is rotatably held around the center line L via rolling bearings 20 and 21. In addition, a fitting groove 2 extending in the direction of arrow P is provided at the tip of the holder body 10.
4 (see FIGS. 2 and 3) is formed, and the tip end portion 28 of the eccentric shaft 18 is projected from the bottom surface 26 of the fitting groove 24. The tip portion 28 has a center line M as a second axis line that is eccentric from the center line L, and is the first eccentric portion referred to in the claims. The eccentric shaft 18 also includes an intermediate portion 32 as a second eccentric portion at a position separated from the tip portion 28 as the first eccentric portion in the centerline L direction. The center line N of the intermediate portion 32 is eccentric to the center line L on the side opposite to the center line M.

A piece 36 having a generally rectangular parallelepiped shape is fitted in the tip end portion 28 of the eccentric shaft 18 in a fitting hole 38 so as to be relatively rotatable. Between the tip portion 28 and the fitting hole 38,
A rolling bearing 40 is provided. Rolling bearing 40
Is a ball bearing having a double clearance in which double rows of balls are arranged between the inner race and the outer race, and the clearance between the inner race and the outer race is slightly smaller than the diameter of the ball. Since the inner race is tightly fitted in the tip end portion 28 and the outer race is tightly fitted in the fitting hole 38, there is no gap in the fitting portion between the tip end portion 28 and the piece 36.

The piece 36 has two sets of two side surfaces which face each other and are orthogonal to the center line M. Of these, the both side surfaces extending in the arrow P direction are defined as side surfaces 42, 43, and the side surfaces 42, 43
Both side surfaces extending in a direction (arrow Q direction) orthogonal to 43 are defined as side surfaces 45 and 46. On the side surfaces 45 and 46 of the piece 36,
The adapter 13 via the linear bearings 48, 49
Although the fitting groove 52 of is fitted so as to be relatively movable,
Reference numerals 2 and 43 are free side surfaces that are not restrained by other members. In other words, the piece 36 and the adapter 13 are fitted to each other in a state where relative movement in the arrow Q direction in FIG. 2 is permitted and relative movement in the arrow P direction is blocked.

The adapter 13 is provided with a fitting portion 54 having the fitting groove 52 and a tool mounting portion 14,
In the fitting portion 54, the fitting groove 24 of the holder body 10
Is fitted so as to be movable relative to each other. The fitting portion 54 has a rectangular shape whose cross section extends in the arrow P direction, and a fitting groove 52 extends in the arrow Q direction at the center thereof. The side surfaces 45 and 46 of the piece 36 are formed in the fitting groove 52.
Are engaged with the inner side surfaces 56, 58 of the bearings via linear bearings 48, 49. Further, as shown in FIG. 3, notches 62 and 63 extending in a direction perpendicular to the arrow Q (direction of the arrow P) are formed on both edges of the tip surface 60 of the fitting portion 54, and the notches are formed. 62, 63 and holder body 1
Pressing plates 71 and 72 are provided so as to straddle the end faces 68 and 69 of the side walls 65 and 66 of the zero fitting groove 24. The pressing plates 71 and 72 are fixed to the end surfaces 68 and 69 of the holder body 10 by bolts 74 and 75, and are engaged with the notches 62 and 63 of the fitting portion 54.

The adapter 13 is fitted in the fitting groove 52 in the fitting portion 54 so as to be movable in the direction along the side walls 65 and 66 (direction of arrow P), and is held by the holder plates 71 and 72. The escape from 10 is prevented. That is, the notches 62 and 63, the pressing plates 71 and 72, the bolts 74 and 75, and the like constitute an attachment device that attaches the adapter 13 to the holder body 10 so as to be relatively movable in the arrow P direction. When the adapter 13 is attached to the holder body 10, a gap is created between the bottom surface of the fitting groove 52 of the adapter 13 and the end surfaces of the eccentric shaft 18 and the piece 36.
The rotation of the eccentric shaft 18 and the movement of the bridge 36 are allowed.

The linear bearing 48 provided between the inner side surface 56 of the fitting groove 52 of the adapter 13 and the side surface 45 of the piece 36 is bent at both ends into a fitting recess formed with an outer race 78 on the side surface 56. The inner race 82 is fitted in the fitting recess formed in the side surface 45. Outer race 78 and inner race 8
V-grooves having an apex angle of 90 degrees are formed on the surfaces facing each other with respect to 2, and a plurality of cylindrical rollers 84 are provided on both sides of the V-grooves so as to extend along the axis of each roller 84. Are alternately arranged so as to face two directions different by 90 degrees. Adjacent rollers 84 are rotatably held by the retainer 86 without contacting each other. Retainer 8
Both ends of 6 are bent in a V shape to form elastically deformable portions 88, and the elastically deformable portions 88 are brought into contact with both bent end portions of the support plate 80. Therefore, it is ensured that the retainer 86 and the roller 84 held by the retainer 86 are assembled in a state where they are positioned in the central portion of the outer race 78 in the longitudinal direction, and the movement of the retainer 86 as the adapter 13 moves causes the elastic deformation portion 88 to move. Allowed by elastic deformation.

The linear bearing 49 also has the same structure as the linear bearing 48.
The dimensions of each part are determined such that the outer peripheral surface of the roller 84 and the groove side surfaces of the V groove of the outer race 78 and the inner race 82 are pressed against each other in a state where the parts 8 and 49 are assembled to each other to provide a negative clearance. The axial dimension of the roller 84 is slightly smaller than the diameter, so that the roller 84 is not pinched by the outer race 78 and the inner race 82 from both sides in the axial direction and is prevented from rotating.

As described above, the tool holding member (not shown) is attached to the tool mounting portion 14, and the tool holding portion of the tool holding member has a cutting tool perpendicular to the longitudinal direction of the fitting groove 52. It is formed in a position and shape to be held in the direction (arrow P direction). In the present embodiment, the cutting tool is a plate-like throwaway tip, and the rake face of the cutting tool is held by the tool holding portion of the tool holding member in a posture that substantially follows one of the radiation from the center line L of the holder body 10. That is, the one radiation is directed in the direction of arrow P. In other words, the cutting tool is held in the direction parallel to the moving direction of the adapter 13. Therefore, the amount of change in the distance from the center line L of the cutting tool due to the movement of the adapter 13 is substantially equal to the amount of movement of the adapter 13, and the blade edge position of the cutting tool in the radial direction due to the rotation of the eccentric shaft 18 is the radial direction. The amount of change can be increased.

At a portion of the holder body 10 corresponding to the intermediate portion 32 of the eccentric shaft 18, a direction (arrow P direction) orthogonal to the longitudinal direction of the fitting groove 52 of the adapter 13 described above, that is, the adapter 13 A fitting hole 90 extending in a direction parallel to the moving direction is formed, and the fitting hole 90 has a balancer 9
2 is movably held. A U-shaped engaging groove 94 is formed in the central portion of the balancer 92 in a direction orthogonal to the moving direction of the balancer 92 (direction of arrow P) and the center line L (arrow Q).
Direction), that is, in a direction parallel to the longitudinal direction of the fitting groove 52, the intermediate portion 32 is formed in the engaging groove 94.
Are engaged.

A nut 100 of a ball screw device 98 is fixed to the rear end portion 96 of the eccentric shaft 18. Nut 10
0, a screw shaft 102 is fitted through a ball (not shown), axial movement of the nut 100 is prevented by the eccentric shaft 18, and rotation of the screw shaft 102 is prevented by rotation preventing means (not shown). . Therefore, the screw shaft 10
When 2 is moved in the axial direction by an axial driving device (not shown), the nut 100 and the eccentric shaft 18 are rotated around the center line L.

The tool holder configured as described above is used by attaching a tool holding member (not shown) to the tool mounting portion 14 as described above. The tool holding member is tightly fitted into the taper shaft-shaped tool mounting portion 14 in the taper fitting hole, and the end surface is brought into contact with the end surface of the fitting portion 54.
It is firmly and accurately fixed to the adapter 13. In that state, if the eccentric shaft 18 is rotated about the center line L, the tip portion 28 rotates about the center line M and the center line L rotates.
And revolves around the center line L while rotating around the center line N. With the rotation of the tip portion 28, the adapter 13 is moved in the arrow P direction via the piece 36, and the balancer 92 is moved in the direction opposite to the center line L with respect to the adapter 13 in the arrow P direction. With the movement of the adapter 13, the tool holding member and the cutting tool are moved, and the radial position of the cutting edge is changed. By adjusting the amount of movement of the screw shaft 102 in the axial direction, the amount of rotation of the eccentric shaft 18 and the amount of movement of the cutting tool in the radial direction can be adjusted. In the present embodiment, the adapter 13 is defined in claim 1. It functions as a so-called moving member.

When the holder body 10 is rotated along with the rotation of the main shaft, the cutting tool mounted on the tool mounting portion 14 is rotated, and boring is performed on a workpiece (not shown). In the present embodiment, since the position of the cutting tool in the radial direction is changed by the rotation of the eccentric shaft 18, the inner diameter of the hole formed in the workpiece is changed, or the cutting tool is machined after the inner diameter machining of the inner peripheral surface of the hole. It can be retracted to a position where it does not come into contact with.

A rolling bearing 40 having a negative clearance is arranged between the eccentric shaft 18 and the bridge 36,
A linear bearing 4 is provided between the adapter 13 and the piece 36.
Since 8 and 49 are arranged with a negative clearance, the eccentric shaft 18 and the piece 36, and the piece 36 and the adapter 13 are provided.
Since there is no play between and, the positioning of the cutting tool in the radial direction can be performed with high accuracy, and the processing accuracy of the work piece can be improved. Furthermore, at these contacts,
Since each member of the eccentric shaft 18, the bridge 36, and the adapter 13 is not worn, the life of each member can be extended.

Further, since the balancer 92 is moved in the direction opposite to that of the adapter 13 (cutting tool), the balance of the entire tool holder can be kept good and the machining accuracy can be improved.

In the above embodiment, the eccentric shaft 1
8 and the piece 36, and the rolling bearings are arranged both between the piece 36 and the adapter 13 to provide the negative clearance, but the rolling bearings are provided only to one of them to form the negative clearance. May be. If either one is negative clearance,
This is because the processing accuracy of the work piece can be improved. Further, since both members in these contact portions are not worn, the life can be extended. However, it is indispensable to dispose the rolling bearing in order to obtain the negative clearance, but just because the rolling bearing is disposed does not necessarily mean that the negative clearance is required. The life extension effect can be obtained without using negative clearance.

Further, in the first invention, the rolling bearing 40 and the linear bearings 48, 49 are not essential.
Even if the rolling bearing 40 and the linear bearings 48 and 49 are not provided, the durability is improved by disposing the bridge between the eccentric shaft and the moving member such as the adapter 13. This is because the eccentric shaft and the piece, and the piece and the moving member are in contact with each other at their surfaces, so that they are less likely to be worn as compared with the case of line contact.

Further, although the balancer 92 is provided in the above embodiment, the balancer 92 is not essential in the first and second inventions. Even if the balancer 92 is not provided, if the rotation speed of the cutting tool is slow,
There is no problem if the workpiece is rotated without rotating the cutting tool.

Further, in the above embodiment, the eccentric shaft 1
Although 8 is rotated by the ball screw device 98, it is also possible to connect a rotation motor or the like to the eccentric shaft 18 so as to be rotated by the motor.

Further, both the bridge and the roller bearing may be arranged between the balancer 92 and the eccentric shaft 18. As a result, rattling of the balancer 92 can be reduced and the processing accuracy of the workpiece can be improved. Between the balancer 92 and the eccentric shaft 18, only one of the bridge and the roller bearing may be arranged. In the case of disposing only the piece, the piece is relatively rotatably fitted to the intermediate portion 32 and the piece is brought into surface contact with the engagement groove 94 of the balancer 92. The inner race is tightly fitted to the intermediate portion 32, and the outer race is brought into line contact with the engagement groove of the balancer 92, which can reduce wear. However,
In order to fit the inner race of the rolling bearing to the intermediate portion 32, the diameter of at least one of the portions of the eccentric shaft 18 located on both sides of the intermediate portion 32 in the axial direction is set to the intermediate portion 32.
Must be smaller than the diameter of the rolling bearing so that the rolling bearing can be fitted into the intermediate portion 32 by passing through the portion having the smaller diameter. The same applies to the piece, but in the case of the piece, it is not necessary if the piece is divided into two on the position diameter of the fitting hole. In addition, the adapter 13 and the holder body 10
Also, a linear bearing may be arranged between the pressing plates 71 and 72.

Further, in the above embodiment, the mounting device for mounting the adapter 13 on the holder body 10 so as to be relatively movable in the direction of the arrow P includes the notches 62, 63 and the pressing plate 7.
Although it was constituted by 1, 72, bolts 74, 75, etc., the mounting device can be of another form. 4 and 5, the adapter 150 as the moving member is
A fitting portion 152 and a tool mounting portion 14 each having a generally disc shape are provided. A fitting groove 154 extending in the direction of arrow Q is formed in the center of the fitting portion 152, and the outer peripheral edge portion of the fitting portion 152 has a direction (arrow) orthogonal to the longitudinal direction of the fitting groove 154. U-shaped notch 15 extending in the P direction)
6, 158 are formed.

On the other hand, the end surface 1 of the holder body 160
Female screw holes 164 and 166 are formed at positions corresponding to the cutouts 156 and 158 of the adapter 150, and bolts 170 and 172 are respectively screwed through the cutouts 156 and 158. The shaft portions of the bolts 170 and 172 are thicker than the male screw portion, the stepped surface formed between the shaft portion and the male screw portion is in contact with the end surface of the holder body 160, and the diameter of the shaft portion is notched 156. , 158 and are only slightly smaller than the width of the adapter 158, the adapter 150 has notches 156, 15
8 is substantially immovable in the width direction. That is, the adapter 150 is attached to the holder body 160 so as to be relatively movable in the direction orthogonal to the longitudinal direction of the fitting groove 154. Further, the bolts 170 and 172 have disc springs 174 and 176 and a flat washer 17 respectively.
8 and 180 are fitted, and the adapter 150 is pressed against the holder body 160 by the elastic force of the disc springs 174 and 176.

In this embodiment, the holder body 160
No fitting groove is formed at the tip end of the eccentric shaft 18, and the tip end 28 of the eccentric shaft 18 is projected from the end surface 162 which is a flat surface.
50 fits. As described above, since the relative movement of the adapter 150 in the arrow P direction is guided by the notches 156, 158 and the bolts 170, 172, a groove (side wall) for guiding the movement of the adapter 150 is formed at the tip of the holder body 160. There is no need to provide it.

Also in this embodiment, similarly to the above-mentioned embodiment, the adapter 150 is moved in the direction of the arrow P along with the rotation of the eccentric shaft 18, and the position of the cutting tool in the radial direction is changed. Although the fitting groove 154 is formed in the adapter 150 in the above embodiment,
A fitting hole having a size that allows relative movement in the arrow Q direction may be formed. Although not specifically exemplified, the present invention can be implemented in various modified and improved modes based on the knowledge of those skilled in the art without departing from the scope of the claims.

[Brief description of the drawings]

FIG. 1 is a front sectional view of a tool holder which is an embodiment common to the first invention to the third invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

3 is a sectional view taken along line III-III in FIG.

FIG. 4 is a front sectional view of a tool holder which is another embodiment common to the first invention to the third invention.

FIG. 5 is a sectional view taken along line VV of FIG. 4;

FIG. 6 is a front sectional view of a conventional tool holder.

[Explanation of reference numerals] 10,160 Holder body 13,150 Adapter (moving member) 14 Tool mounting part 18 Eccentric shaft 28 Tip part 32 Intermediate part 36 Piece 38 Fitting hole 40 Rolling bearing 45,46 Side surface 48,49 Linear bearing 52 , 154 Fitting groove 62, 63 Notch 71, 72 Holding plate 74, 75 Bolt 92 Balancer 156, 158 Notch 170, 172 Bolt

Claims (3)

[Claims] 1. A holder main body, and a holder main body rotatably held around the first axis,
An eccentric shaft having an eccentric shaft portion having a second axis line that is eccentric from the first axis line, and the eccentric shaft portion is rotatably fitted in the fitting hole so as to be parallel to a straight line perpendicular to the second axis line. A moving member having a piece having two extending side surfaces, a fitting groove that fits with the two side surfaces of the piece so as to be movable relative to each other, and a tool attachment portion to which a cutting tool is attached, and the moving member is an end surface of the holder body. And a mounting device mounted so as to be relatively movable in a direction substantially orthogonal to the fitting groove. 2. Between the eccentric shaft portion and the fitting hole of the bridge,
2. The tool holder according to claim 1, wherein a rolling bearing is arranged with a negative clearance in at least one of the two side surfaces of the piece and the fitting groove of the moving member. 3. A second eccentric shaft portion at a position axially separated from the first eccentric shaft portion, which is the eccentric shaft portion, and a second eccentric shaft portion with respect to the first axis line. Is provided in a state of being eccentric to the opposite side, and a balancer movably held by the holder main body on the second eccentric shaft portion in a direction parallel to the moving direction of the moving member is the same as the moving direction of the balancer. The tool holder according to claim 1 or 2, wherein the tool holder is engaged in an engagement groove extending in a direction perpendicular to the one axis.