JPS6131769Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a tool holder suitable for powerful cutting work such as end milling, and in particular, a tool shank in which a thin tapered cylindrical portion of the chuck body is elastically deformed in the diametrical direction and attached to the inner diameter of the holder. This invention relates to an improvement of a tool holder configured to grip a tool holder.

Conventionally, such a tool holder has a structure as shown in, for example, Japanese Utility Model Publication No. 44-23894. In such a structure, the gripping force is obtained only by the tightening force of the screw, and it is easy to loosen due to vibrations caused by cutting, so a means to prevent loosening is required, which makes the structure more complicated. Moreover, it has the disadvantage that high clamping force cannot be obtained and strong cutting is difficult.

The present invention solves the above-mentioned drawbacks and provides a tool holder that can obtain high clamping force and also has a loosening prevention function to enable powerful cutting.The details will be explained below using examples. do.

As shown in FIGS. 1 to 3, the tool holder according to the present embodiment has a machine tool spindle (not shown) at one end.
It has a shank 1a that can be attached to a tapered hole, a flange 1b in the middle in the longitudinal axis direction, and a thin tapered cylindrical part 1d having an inner diameter 1c for receiving a shank T of a tool to be gripped at the other end. and a chuck body 1 having an external thread 1e bored between it and the flange 1b on the outer diameter continuing from the thin tapered cylindrical portion 1d, and a taper on the inner diameter that engages with the thin tapered cylindrical portion 1d of the chuck body 1. It has a cylindrical shape with a hole 2a, and a small diameter cylindrical part 2c is formed at one end (small inner diameter side) of this cylindrical outer diameter 2b, and a cylindrical outer diameter 2b end periphery on the small diameter cylindrical part 2c side. As shown in FIGS. 2 and 3, the groove wall 2d ₁ extends in the axial direction and is approximately parallel to the axis (in the embodiment, at an angle of β° (approximately 20' to 30') to the axis). ) and groove wall 2d ₂ inclined at α° with respect to the axis.
and a ring 2 having a roughly U-shaped groove 2d connected by an R surface _2d3 , and a ring 2 housed in the groove 2d of the ring 2 in a state inclined at α° with respect to the axis as shown in FIG. It has three cylindrical levers 3 with both ends spherically finished, and inner diameters 4a and 4b that are located outside the ring 2 and accommodate an outer diameter 2b and a cylindrical portion 2c. A hemispherical groove 4c for receiving one end of the lever 3 is formed in three equally divided positions on the circumference corresponding to the groove 2d, and the collar is rotatable within the operating range of the lever 3 in the groove 2d with respect to the ring 2. 4, an inner diameter 6a which is rotatably and integrally connected in the axial direction to the open end of the inner diameter 4a of this collar 4 via a steel ball 5 and accommodates the outer diameter 2b of the ring 2 therein; A screw hole 6b that is screwed into the male screw 1e of the chuck body 1 formed by
It is composed of a tightening nut 6 having a.

To further explain the groove 2d of the ring 2 in the above embodiment, first, before the tool is attached, the tightening nut 6 is closer to the right than the position shown in FIG. The housed lever 3 is assembled in a state in which it is tilted at α° to one side, that is, in a state in which it is in contact with the groove wall 2d ₂ of the groove 2d, as shown by the solid line in FIG.
In this state, the shank of the tool T to be gripped is inserted into the inner diameter 1c of the chuck body 1.

Then, the tightening nut 6 is rotated in the tightening direction. This operation causes the threaded connections (1e and 6b) with the chuck body 1 to act as an axial force on the ring 2 via the collar 4 and the lever 3, pulling the ring 2 to the left in FIG. Therefore, due to the movement of the ring 2, the thin tapered cylindrical portion 1d of the chuck body 1 is elastically deformed in the diametrical direction and reduced in diameter, thereby gripping the tool T. When the tightening nut 6 is further rotated, the ring 2 is further drawn to the left in the axial direction, and finally the left end surface of the tightening nut 6 abuts the right end surface of the flange 1b of the chuck body 1, and the ring 2 is stopped in the axial direction.

Next, the collar 4 is rotated in the tightening direction (arrow) as shown in FIG. This causes the lever 3 to rise from its tilted position to the position shown by the two-dot chain line in FIG. The length of the lever 3 as shown in Figure 3
The axial distance _S2 from the bottom of the rounded surface _2d3 of the groove 2d of the ring 2 to the bottom of the hemispherical groove 4c of the collar 4 is set smaller than S1, and the collar ₄ is tightened via the steel ball 5. Since it is fixed in the axial direction by the nut 6, the force in the axial direction due to the rise of the lever 3 is applied to the ring 2, and the ring 2
is moved by an amount St in the axial direction (arrow), and therefore a stronger gripping force is applied to the tool T.
Further, when the collar 4 has been rotated in the tightening direction, the axis of the lever 3 is at a stable position beyond the axis of the chuck body 1 by β degrees, that is, beyond the operational dead center of the lever 3. In reality, this β° may be a small angle of 20 to 30 minutes, and can be considered to be approximately parallel to the axis.

In addition to the embodiment described above, as shown in FIG. 4, a flange-like projection 10 is formed that projects inward at the front end of the collar 4, and this projection 10 is engaged with the front end of the ring 2 to tighten it. Similar effects can be obtained even if the structure is such that the tightening force of the nut 6 is directly transmitted from the collar 4 to the ring 2. Further, as shown in FIG. 4, by providing a spiral groove or an annular groove 11 at an appropriate pitch on the outer periphery of the thin tapered cylindrical portion 1d of the chuck body 1, elastic deformation is facilitated and the gripping effect is increased. It is also possible. In addition, in this embodiment, the tightening nut 6 and the collar 4 are configured to be operated separately, but the practical effects can be further enhanced by changing the design so that both can be operated integrally.

As explained above, the double locking method of tightening with screws and lever is used, which significantly increases the gripping force compared to the conventional method and enables powerful cutting. Since it is configured to abut against the flange, the rigidity is improved, and the lever structure provides a stable gripping force without loosening due to vibration or the like. Furthermore, it is possible to provide a tool holder with high practical effects such as excellent dust-proofing effects.

[Brief explanation of the drawing]

FIG. 1 is a front sectional view of the embodiment of the present application, FIG. 2 is a sectional view taken along line AA in FIG. 1, and FIG. 3 is a sectional view taken along line B--
B sectional view and FIG. 4 are partial sectional views showing other embodiments, respectively. Explanation of symbols, 1...chuck body, 2...ring, 3...lever, 4...collar, 5...steel ball,
6...Tightening nut, T...tool.

Claims (1)

[Claims for Utility Model Registration] 1. Has a shank attached to the machine tool spindle hole at one end, has a flange in the middle in the longitudinal direction,
a chuck body having a thin-walled tapered cylindrical portion having an inner diameter formed to receive a shank of a tool to be held at the other end, and having a male thread on an outer diameter continuous to the thin-walled tapered cylindrical portion between the chuck body and the flange; It has a tapered hole that engages with a thin tapered cylindrical portion, extends in the axial direction to predetermined equally divided positions on the outer periphery of one end side, and is generally formed by connecting a groove wall that is substantially parallel to the axis and an inclined groove wall with an R surface. a cylindrical ring having a U-shaped groove; a lever housed in the groove of the ring in a state inclined with respect to the axis; a lever located outside the ring and corresponding to the groove of the ring; a collar that has a groove on its inner diameter bottom surface for receiving one end of the lever and is rotatable relative to the ring within the operating range of the lever; a collar that is rotatably connected to the collar and has a ring receiving hole in its inner diameter; A tool holder comprising: a tightening nut having a screw hole that is screwed into a male thread of a main body; 2. The tool holder according to claim 1, wherein a flange-like projection is formed inward at the front end of the collar, and this projection is engaged with the front end of the ring. 3. The tool holder according to claim 1 or 2, which is provided with a spiral groove or an annular groove of an appropriate pitch on the outer periphery of the thin tapered cylindrical portion of the chuck body.