JP2022190536A - Tool holder and machine tool - Google Patents

Abstract

To make it possible to add damping properties stably for a long period of time, and to obtain high vibration suppression effect at even a position near a tool tip.SOLUTION: A tool holder 10 includes a base 2 having a tool insertion hole 3 in which a base end part 33a of a tool 33 is inserted, and tool fixing bolts 5, 5 which fix the base end part 33a inserted in the tool insertion hole 3 in the base 2, and comprises a sleeve 11 that is attached to the tool 33 and is fixed to the base 2. The sleeve 11 has a slit 15 extending in an axial direction, and an adjustment bolt 12 which can adjust a size of an inner diameter of the sleeve 11. By the adjustment bolt 12, the sleeve 11 can grip the tool 33 with a gripping force which is lower than a fixing force by the tool fixing bolts 5, 5, and which can permit movement of the tool 33 relative to the sleeve 11 when vibration has occurred due to processing.SELECTED DRAWING: Figure 6

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present disclosure relates to a tool holder having a function of suppressing vibration generated in the tool during machining, and a machine tool including the tool holder in a machine tool that performs machining while relatively moving the tool and the workpiece. .

In a machine tool that supports a tool on a rotatable work and moves the tool and work relative to each other while feeding the work, when the tool is used with a large overhang as in boring, the tool rigidity is reduced. A decrease in the cutting force may cause large machining vibration (hereafter referred to as chatter), which causes problems such as tool breakage and poor machined surface quality.
Therefore, as a conventional technique for improving vibration damping properties to suppress chatter, Patent Document 1 describes an invention for suppressing tool vibration by providing a tool holder with a space filled with a viscous fluid. It is Patent Document 2 describes an invention in which a damping member is interposed between a tool and a tool holder. Patent Document 3 describes an invention in which a viscoelastic body such as nitrile rubber is pressed against a tool.
In addition, Non-Patent Document 1 describes a vibration isolation tool that improves holding rigidity by inserting a tool into a tool insertion hole having a slotted structure and tightening it with a bolt.

Japanese Patent No. 6177602 Japanese Utility Model Laid-Open No. 5-88804 Japanese Patent No. 5131826

"Ultimate anti-vibration tool" Silent Tools SANDVIK Electronic catalog page 4 "How to clamp the tool", [searched on May 31, 2021], Internet <https://www.sandvik.coromant.com/ SiteCollectionDocuments/downloads/en/brochures/CG-036J-R2_SilentTools.pdf＞

However, in the methods of Patent Documents 1 to 3, while it is possible to add damping properties, it is necessary to use rubber or damping materials, which generally have lower durability than metal, and the tool tip, which is the processing position, must be used. There is concern about the durability of long-term use in a place close to
In addition, in the methods of Patent Documents 1 and 3 and Non-Patent Document 1, while it is possible to add a certain damping property, it is thought that the greater the vibration amplitude, the greater the damping property can be obtained. If the damping mechanism is installed near the root of the tool, where the vibration amplitude becomes smaller, there is a risk that the damping performance will be improved only to a limited extent.

Therefore, the present disclosure has been made in view of the above problems, and is a tool that can stably add damping properties for a long period of time and can obtain a high vibration suppression effect even at a position near the tip of the tool. The object is to provide a holder and a machine tool.

In order to achieve the above object, a first configuration of the present disclosure includes a base provided in a machine tool and having a tool insertion hole into which a proximal end of a tool is inserted; and the base inserted into the tool insertion hole. fixing means for fixing the end portion within the base, comprising:
A sleeve is provided that is fitted over at least a protruding portion of the tool from the base and is fixed to the base, and the sleeve has at least one slit extending in the axial direction and an inner diameter of the sleeve that can be adjusted. and an adjustment mechanism,
The adjusting mechanism allows the sleeve to grip the tool with a gripping force that is lower than the fixing force of the fixing means and that allows relative movement of the tool with respect to the sleeve when vibration occurs due to processing. It is characterized by
Another aspect of the present disclosure is characterized in that, in the above configuration, the sleeve has a length enough to be inserted also into the tool insertion hole.
In another aspect of the present disclosure, in the above configuration, the inner diameter of the sleeve is formed to be smaller than the outer diameter of the tool, and the adjustment mechanism is capable of widening the opening width of the slit, and the adjustment The tool can be inserted and removed by increasing the width of the opening by means of a mechanism, and the sleeve can grip the tool with the gripping force without increasing the width of the opening. .
In another aspect of the present disclosure, in the above configuration, the inner diameter of the sleeve is formed to be larger than the outer diameter of the tool, and the adjustment mechanism is capable of narrowing the opening width of the slit. A mechanism enables insertion and removal of the tool without reducing the width of the opening, and the sleeve is capable of gripping the tool with the gripping force with the width of the opening being reduced. .
To achieve the above object, a second configuration of the present disclosure is a machine tool comprising the tool holder of the first configuration of the present disclosure.

According to the present disclosure, it is possible to stably add damping properties for a long period of time without using materials with low durability other than metal. In addition, it is possible to stably impart high damping performance for general use even at a position near the tip of a tool where vibration amplitude is large when chatter occurs for any tool. Therefore, highly efficient machining can be realized.

1 is a schematic configuration diagram of a conventional tool holder; FIG. FIG. 2 is a schematic configuration diagram of the AA cross section of FIG. 1; 1 is a schematic diagram of a tool holder of the present disclosure; FIG. 4 is a schematic diagram showing the shape of the sleeve of FIG. 3; FIG. FIG. 4 is a schematic configuration diagram of a BB cross-sectional portion of FIG. 3; FIG. 4 is a schematic configuration diagram of a CC cross-sectional portion of FIG. 3; FIG. 11 is a perspective view showing a modified example of the sleeve; FIG. 11 is a perspective view showing another modification of the sleeve; FIG. 5 is a schematic configuration diagram showing a modified example of the tool holder; FIG. 10 is a schematic configuration diagram of a DD cross-sectional portion of FIG. 9; FIG. 5 is a schematic configuration diagram showing another modification of the tool holder;

First, the structure of a conventional tool holder will be explained with reference to the drawings.
FIG. 1 is a schematic configuration diagram showing the configuration of a conventional tool holder 1. As shown in FIG. FIG. 2 is a schematic configuration diagram showing a cross section along AA in FIG. 1 (a cross section along a plane defined in the front-rear and up-down directions; the same shall apply hereinafter).
In this example, the tool holder 1 is applied to a turning turret 31 of a lathe 30, which is an example of a machine tool. A tool 33 held by the tool holder 1 has a substantially circular cross section and a tip 34 at its tip. For the sake of convenience, the tip side (tip 34 side) of the tool 33 in FIG.
The tool holder 1 has a block-shaped base 2 fixed to a mounting surface 32 on the outer periphery of a swivel turret 31 . A tool insertion hole 3 into which a tool 33 is inserted from the rear end is formed through the base 2 in the front-rear direction. Three base fixing bolts 4, 4, . Two tool-fixing bolts 5, 5 are screwed in the front-rear direction at the center of the base 2 in the left-right direction above the tool insertion hole 3. As shown in FIG.
A base end portion 33a of the tool 33 having the tip 34 attached to the tip thereof is inserted into the tool insertion hole 3 from the front. In this state, when the tool fixing bolts 5 and 5 are screwed into the base 2 from above, the base end portion 33a of the tool 33 is pressed against the lower inner wall of the tool insertion hole 3 . As a result, the tool 33 is fixed to the base 2 with the tip portion 33b protruding from the tool insertion hole 3. As shown in FIG.

Next, embodiments of the present disclosure will be described with reference to the drawings. However, the same components as those of the conventional tool holder 1 are denoted by the same reference numerals, and overlapping descriptions are omitted.
FIG. 3 is a schematic configuration diagram showing an example of the tool holder 10 of the present disclosure. FIG. 4 is a schematic diagram showing the shape of the sleeve 11 that constitutes the tool holder 10. As shown in FIG. Here also, front and rear and up and down are explained in the same directions as in FIG. 5 is a schematic configuration diagram of the BB cross section of FIG. 3, and FIG. 6 is a schematic configuration diagram of the CC cross section of FIG.
The tool holder 10, like the tool holder 1, includes a base 2, base fixing bolts 4, and tool fixing bolts 5. As shown in FIG. In addition to this, the tool holder 10 further includes a sleeve 11 and three adjustment bolts 12, 12, .
The sleeve 11 has a sleeve inner hole 13 with an inner diameter smaller than the outer diameter of the tool 33 , and a collar portion 14 that determines the retracted position of the sleeve 11 in the axial direction on the end face of the base 2 . A slit 15 is formed in the side surface of the sleeve 11 over the entire length in the axial direction. In the sleeve 11 above the slit 15, adjustment bolt holes 16, 16, . ing. On the upper surface of the sleeve 11 on the rear side of the flange 14, there are bolt through holes 17, 17 for holding the tool 33 by pressing it against the inner wall of the sleeve inner hole 13 with the tool fixing bolts 5, 5. is formed in

A procedure for mounting the tool 33 in the tool holder 10 configured as described above will be described below.
First, the base 2 is fixed to the mounting surface 32 of the turning turret 31 with the base fixing bolts 4 . Next, the sleeve 11 is inserted into the tool insertion hole 3 until the flange 14 hits the end surface of the base 2 . Next, by tightening the adjusting bolt 12 and pressing the lower end against the lower surface of the slit 15 , the opening width of the slit 15 is widened and the inner hole 13 of the sleeve is made larger than the outer diameter of the tool 33 . Next, after inserting the tool 33 into the sleeve inner hole 13 from the rear end and adjusting the position so that the tool protrudes by a predetermined amount, the adjustment bolt 12 is loosened and the inner diameter of the sleeve inner hole 13 is adjusted to the inner diameter of the sleeve inner hole 13 by the tool 33 . , the tool 33 is held by the sleeve 11. Finally, through the bolt holes 17, 17, the base end portion 33a of the tool 33 is pressed against the inner wall of the sleeve inner hole 13 by the tool fixing bolts 5, 5, and the sleeve 11 is pressed against the inner wall of the tool insertion hole 3. The proximal end portion 33 a of the tool 33 and the sleeve 11 are fixed to the base 2 by abutting.

Turning is performed on a lathe 30 using this tool holder 10, and when machining vibration occurs, the sleeve 11 and the proximal end portion 33a of the tool 33 near the base 2 tightened with the tool fixing bolt 5 , are held and fixed with high pressure (fixing force) that does not move relative to each other. On the other hand, the tip 33b side of the tool 33 contacts the sleeve 11 with a low pressure (gripping force) that causes relative movement. At this time, relative movement occurs while the objects rub against each other, thereby exhibiting high damping properties due to energy consumption.
Since the area where relative movement is generated is not tightened with bolts, the contact pressure is determined by the interference between the tool 33 and the sleeve inner hole 13 regardless of the operator's setting method, and performance variations can be suppressed. can. As a result, during machining, the tool position does not change due to the rigid fixation of the tool holder 10 at the rear, and stable frictional damping occurs in the front contact area, making it possible to suppress machining vibration.

As described above, the tool holder 10 and the lathe 30 of the above configuration have the base 2 having the tool insertion hole 3 into which the base end portion 33a of the tool 33 is inserted, and the base end portion 33a inserted into the tool insertion hole 3. 2, and a sleeve 11 that is mounted on the tool 33 and fixed to the base 2, and the sleeve 11 has a slit 15 extending in the axial direction. and an adjustment bolt 12 (adjustment mechanism) capable of adjusting the size of the inner diameter of the sleeve 11, and the adjustment bolt 12 allows the sleeve 11 to have a lower fixing force than the tool fixing bolts 5, 5, In addition, the tool 33 can be gripped with a gripping force that allows relative movement of the tool 33 with respect to the sleeve 11 when vibration occurs due to machining.
Therefore, it is possible to stably add damping properties for a long period of time without using materials other than metals, which generally have low durability. In addition, it is possible to stably impart high damping performance for general use even at a position near the tip of a tool where vibration amplitude is large when chatter occurs for any tool. Therefore, highly efficient machining can be realized.

In particular, since the sleeve 11 has a length enough to be inserted into the tool insertion hole 3 , the tool 33 can be inserted into the tool insertion hole 3 together with the sleeve 11 and fixed with the tool fixing bolts 5 , 5 .
The inner diameter of the sleeve 11 is smaller than the outer diameter of the tool 33 , and the adjustment bolt 12 can widen the opening width of the slit 15 . The sleeve 11 is capable of gripping the tool 33 with a gripping force that enables relative movement of the tool 33 without widening the width of the opening while allowing the insertion and removal of the tool 33 . Therefore, the tool 33 can be gripped by the sleeve 11 with an appropriate gripping force simply by loosening the adjustment bolt 12 .

Modifications of the present disclosure will be described below.
FIG. 7 shows a modified sleeve 11A. In the above-described embodiment, the slit 15 was provided over the entire length in order to improve the openability of the sleeve 11. However, the portion of the tool 33 that has a large amount of vibration due to machining and a large relative displacement is located where the damping effect due to friction is large. Since it is only on the tip side, in this sleeve 11A, the slit 15 is provided only on the tip side of the tool 33 in front of the collar portion 14 . Other configurations of the tool holder 10 are the same as those of the above embodiment.
FIG. 8 shows another modified sleeve 11B. In this sleeve 11B, two slits 15, 15 are provided only on the tip side of the tool 33 in front of the collar portion 14 on both left and right side surfaces. Other configurations of the tool holder 10 are the same as those of the above embodiment. Note that the slits may be provided not only on the left and right but also on the top and bottom, or may be provided at three or more locations.

FIG. 9 is a schematic configuration diagram showing a modification of the tool holder. FIG. 10 is a schematic configuration diagram of the DD section of FIG.
In the tool holder 10A shown in FIG. 9, a short sleeve 11C with slits 15 (or a plurality of slits) in the side surface is used. A collar portion 18 provided at the rear end of the sleeve 11C is fixed to the end surface of the base 2 by sleeve fixing bolts 19, 19, .
The tool 33 has an outer diameter equal to the inner diameter of the tool insertion hole 3 and is inserted into the tool insertion hole 3 in the same manner as the conventional tool holder 1 .
Therefore, after inserting the tool 33 into the sleeve inner hole 13 and the tool insertion hole 3 from the rear end and adjusting the position so that the tool protrudes by a predetermined amount, the adjustment bolt 12 is loosened to remove the sleeve inner hole 13. The inner diameter is made smaller than the outer diameter of the tool 33, and the tip 33b of the tool 33 is gripped by the sleeve 11C. In this state, the base end portion 33a of the tool 33 is fixed to the base 2 by the tool fixing bolts 5,5.

It should be noted that the configuration of the tool holder of the present disclosure is not limited to the aspects described in the above embodiments, and can be appropriately modified as necessary without departing from the gist of the present invention.
For example, in the above embodiment, the adjustment bolt 12 is tightened to increase the diameter of the sleeve inner hole 13 whose inner diameter is smaller than the outer diameter of the tool 33, and the tool 33 is inserted. Although the sleeve 11 (11A to 11C) grips the tool 33 with a predetermined gripping force, it can be modified as shown in FIG.
In the tool holder 10B of FIG. 11, the adjustment bolt 12 is screwed to the bottom of the slit 15 using a sleeve 11D in which the inner diameter of the sleeve inner hole 13 is larger than the outer diameter of the tool 33 . Therefore, the tool 33 can be inserted into and removed from the sleeve 11D without tightening the adjustment bolt 12. As shown in FIG. The gripping force of the sleeve 11D is adjusted by tightening the adjustment bolt 12 to reduce the opening width of the slit 15 and reduce the inner diameter of the sleeve inner hole 13. As shown in FIG. In this case, the tool 33 can be easily inserted and removed, although the damping performance is less stable than in the above embodiment.
11, the sleeve may be a short sleeve as shown in FIG. 9, or may have a plurality of slits.

In the above embodiment, the inner diameter of the sleeve is adjusted using the adjusting bolt as the adjusting mechanism, but the inner diameter of the sleeve may be adjusted using an adjusting mechanism such as a spring or a lever.
Furthermore, in the above embodiment, the base and the sleeve are composed of one member, but it goes without saying that they may be composed of a plurality of members joined together.
On the other hand, the cross-sectional shapes of the inner holes of the base and sleeve are not limited to circular. Other shapes such as elliptical or polygonal may be used to match the cross-sectional shape of the sleeve or tool.
In addition, the tool holder of the present invention can also be applied to machine tools other than lathes.

1, 10, 10A, 10B Tool holder 2 Base 3 Tool insertion hole 4 Base fixing bolt 5 Tool fixing bolt 11, 11A to 11D Sleeve 12 Adjustment bolt 13 Sleeve inner hole 14, 18 Collar portion 15 Slit 16 Adjustment bolt hole 17 Bolt through hole 19 Sleeve fixing bolt 30 Lathe, 31 Turning turret, 32 Mounting surface, 33 Tool.

Claims (5)

A tool provided on a machine tool, comprising: a base having a tool insertion hole into which a proximal end of the tool is inserted; and fixing means for fixing the proximal end inserted into the tool insertion hole within the base. a holder,
A sleeve is provided that is fitted over at least a protruding portion of the tool from the base and is fixed to the base, and the sleeve has at least one slit extending in the axial direction and an inner diameter of the sleeve that can be adjusted. and an adjustment mechanism,
The adjusting mechanism allows the sleeve to grip the tool with a gripping force that is lower than the fixing force of the fixing means and that allows relative movement of the tool with respect to the sleeve when vibration occurs due to processing. A tool holder characterized by: 2. The tool holder according to claim 1, wherein the sleeve has a length enough to be inserted into the tool insertion hole. The inner diameter of the sleeve is smaller than the outer diameter of the tool, and the adjusting mechanism can widen the opening width of the slit. 3. The tool holder according to claim 1 or 2, wherein said sleeve can grip said tool with said gripping force without widening said opening width. The inner diameter of the sleeve is formed to be larger than the outer diameter of the tool, and the adjusting mechanism can reduce the opening width of the slit. 3. The tool holder according to claim 1, wherein the sleeve can be inserted and removed, and the sleeve can grip the tool with the grip force when the width of the opening is reduced. A machine tool comprising the tool holder according to any one of claims 1 to 4.

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