JP2005313263A - Collet chuck tool holder and collet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem wherein holding accuracy is affected due to imparting of distortion to a cutting tool by pulling of the cutting tool by a collet fastening operation when fixing the cutting tool of a small diameter at a prescribed position by a tool holder of a collect chuck system. <P>SOLUTION: In this tool holder, a cylindrical part is extended and formed continuously to a tapered part of the collet, a screw hole is formed in the cylindrical part, a member for positioning the cutting tool is screwed and mounted. The tool holder is integrally provided with a cutting tool end receiving part on an end face side, and an adjusting screw structure for adjusting the position of the constituting tool at the rear part inside the collet. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a collet chuck type tool holder for holding a drill or the like, and more particularly to a tool holder for accurately and reliably holding a cutting tool such as a small-diameter drill.

  Conventionally, such a collet chuck type tool holder has been widely used for holding a cutting rotary tool such as a drill. For example, a structure as clearly shown in FIG. 3 is known. This tool holder has a collet chuck portion 12 configured on the opposite side of the holder main body 10 having a shank portion 11 to be mounted on the spindle end S of the machine tool. The collet chuck portion 12 is a holder main body. 10, a tapered hole 10a formed in the end portion, an outer shape taper 21 to be inserted into the tapered hole 10a, a through hole 22 in the center, a collet 20 in which a slit is formed from the front and rear, and an end portion of the holder body 10 A tightening nut 30 that is screwed into the threaded portion 10b formed on the outer periphery, and the collet 20 is pushed inward of the holder body 10 by rotating the tightening nut 30 and is radially inward at the taper coupling portion. The cutting tool T that has been reduced in diameter and attached to the through hole 22 is gripped. In the figure, 50 is a steel ball, 60 is a ring member that is axially connected to the steel ball inside the tightening nut 30 and engages the outer shape of the collet to interlock the collet 20 with the tightening nut 30.

Incidentally, in such a collet chuck type tool holder, conventionally, as shown in FIG. 4, an adjusting screw 40 for setting the protruding length of the cutting tool to a predetermined length is provided following the tapered hole 10a in the holder body 10. What is attached to the screw hole 10c formed in the hole is used, and since it can be easily adjusted simply by turning the screw 40, it is frequently used.

However, in this conventional structure, particularly when holding a cutting tool having a small diameter, the cutting tool T is inserted into the tool holder body 10 and the rear end is engaged with the adjusting screw 40 as shown in FIG. After making contact with the hole 41, the tightening nut 30 is turned to perform attachment work. At that time, as described with the arrows shown in the figure, when the tightening nut 30 is first turned, the nut 30 moves to the left ( Arrow a). Then, the collet 20 is pushed into the taper hole 10a, and the diameter is reduced in the radial direction (arrow b), and further drawn into the back (arrow c). Therefore, the cutting tool T is pulled together (arrow d), and the rear end of the cutting tool T acts as a strong pushing force on the contact portion 41 of the adjusting screw 40. Therefore, a reaction force against the pushing force acts on the adjusting screw 40 as shown by an arrow e. For this reason, a strong force acts on the shank portion of the cutting tool from both sides in the axial direction, and in the case of a cutting tool with a small diameter as shown in the figure, the seat as shown by a two-dot chain line in the figure. This causes problems such as bending and adverse effects caused by the bending, for example, a decrease in shake accuracy.
In addition, the cutting tool may be cooled through the coolant fluid into such a tool holder or sprayed to the cutting point. In this case, the same adjusting screw is used, which has the same problems. It was.
For this reason, as shown in Patent Document 1, a tool positioning member made of an elastic body such as hard rubber has been proposed. Furthermore, similar structures as shown in Patent Document 2 to Patent Document 4 are also known.

   In the structure shown in this patent document, when the cutting tool is pressed as described above, the cutting tool is pushed in, but since the distortion is absorbed by the elasticity of the positioning member, the influence as described above is reduced.

However, with such a structure, as described above, the axial force when the cutting tool T is retracted by the operation of the tightening nut 30 is considerably strong, so that the tool contact portion of the positioning member is plastically deformed. If the cutting tool is removed and replaced, the mounting position may be out of order, and if the coolant fluid is allowed to flow inside, the sealing performance may be reduced. It was also a thing. Furthermore, depending on the type of coolant fluid, there is a material that deteriorates rubber and resin. In such a case, there is a problem in versatility because it cannot be used.

JP 2001-150269 A No. 5-13476 Japanese Utility Model Publication No. 6-34920 JP-A-8-141878

The problem to be solved is that when a small-diameter cutting tool is fixed at a predetermined position using a collet chuck type tool holder, the drawing of the cutting tool due to the collet tightening operation distorts the cutting tool, which affects the holding accuracy. It is in the point which gives.

  The present invention is characterized in that an adjustment screw structure for adjusting a tool position, which has been conventionally configured on the tool holder side, is integrally provided at the rear part inside the collet, and is a shank to be mounted on a spindle end of a machine tool. A collet chuck configured on the opposite side of the holder main body having a portion, and the collet chuck includes a tapered hole formed at an end of the holder main body, an outer taper and a center inserted into the tapered hole A collet that has a through hole for inserting a cutting tool in the shaft core part, and has a slit groove for radial deformation into the through hole, and a screw that is screwed into a screw part formed on the outer periphery of the end of the holder body The collet is pushed inward of the holder body by rotating the tightening nut, and the cutting tool mounted in the collet through-hole is reduced in diameter in the radial direction at the taper coupling portion. In the collet chuck tool holder, a cylindrical portion extending form following the tapered section of the collet, the cylindrical portion to form the screw hole, the cutting tool positioning member, characterized in that the threaded attachment.

  Since the present invention is configured as described above, when mounted on a collet chuck type tool holder as described above, the collet is retracted in the axial direction even if the collet is reduced in diameter by rotating the tightening nut. No force is generated, the cutting tool is not distorted, and the cutting tool can be reliably held.

The objective of holding the cutting tool with high holding accuracy without affecting the cutting tool due to the collet tightening operation is achieved by a simple configuration in which the tool position adjusting means is built in the collet itself. I was able to.

  The present invention will be described based on the illustrated embodiment. First, as shown in FIG. 1, the tool holder according to the embodiment has a shank portion 102 attached to the spindle end S of the machine tool (this portion is the same as FIG. 3 showing the conventional example, and is omitted in this figure). A collet chuck portion 112 configured on the opposite side of the holder main body 110 having a taper hole 110a formed at the end of the holder main body 110 and the taper hole 110a. An outer shape taper 121 to be inserted, a through hole 122 in the center, a collet 120 formed with slits from the front and rear, and a tightening nut 130 to be screwed into a screw portion 110b formed on the outer periphery of the end portion of the holder body 110 are provided. By rotating the tightening nut 130, the collet 120 is pushed inward of the holder main body 110, and the diameter is reduced inward in the radial direction at the taper coupling portion. The collet 120 of the present invention forms a cylindrical portion 122 following the outer shape taper 121, and a screw hole 123 is formed in the center from the rear end surface. It is communicated with the cutting tool insertion hole 122 formed from the front end side. An adjustment screw 140 as shown in the above-described known example is screwed into the screw hole 123. Therefore, as shown in FIG. 1, the rear end of the cutting tool T is abutted against a conical receiving surface 141 formed at the front end of the adjusting screw 140 as in the prior art. Further, as shown in the external view of FIG. 2, a plurality of slits 124 are formed in the outer tapered portion 121 on the distal end side of the collet 120 from the distal end surface side beyond the outer tapered portion 121 portion. In the figure, 150 is a steel ball, 160 is a ring member that is axially connected to the steel ball 150 inside the tightening nut 130 and engages the outer shape of the collet 120 to interlock the collet 120 with the tightening nut 130. This is the same as the conventional structure.

Since it is configured in this manner, the cutting tool is configured so as not to be affected by the axial movement of the collet due to the axial movement caused by the turning operation of the tightening nut 130. Since it can be made to act effectively, distortion and buckling of a cutting tool can be prevented effectively. Furthermore, since the adjustment screw portion is formed inside the collet as compared with the conventional case, the position can be adjusted before being attached to the tool holder body in advance, and a secondary effect that adjustment work is facilitated can be obtained. In addition, it is possible to easily achieve more accurate position adjustment by measuring the amount of axial movement when turning the tightening nut and pushing the collet in advance, and setting the adjustment screw position taking that amount into account. is there.

  In the example, the slot formed on the collet has been described as being formed only from the front end. However, in the same manner as in the case of a normal collet, the groove is alternately formed from both the front end side and the rear end side. it can. That is, the directionality and number of slots are not limited. Furthermore, the shape of the adjusting screw is not limited to the embodiment, and the cutting tool rear end abuts on a flat surface or other shapes can be adopted.

In the embodiment, the rear end portion of the tool holder, that is, the mounting portion to the spindle end S is shown in a so-called BT shank shape. Even if it has such a special mounting shank portion, it can be similarly adopted.

1 shows an overall view in partial section of a tool holder according to the invention. The external view of the collet of FIG. 1 is shown. The whole figure which carried out the partial cross section which shows a prior art example is shown. Explanatory drawing of the effect | action of the partial cross section of a prior art example.

Explanation of symbols

110 Tool holder body
110a
Taper hole
110b Screw part
120 collet
121 Tapered hole
122 Cutting tool insertion hole

123 Screw hole

124 Slotting groove

130 Tightening nut

140 Adjustment screw

141 Conical receiving surface T
Cutting tools

Claims (2)

A collet chuck configured on the opposite side of the holder main body having a shank portion to be attached to the spindle end of the machine tool, the collet chuck including a tapered hole formed at the end of the holder main body, A collet having an outer shape taper to be inserted into the taper hole and a through-hole for inserting a cutting tool in the central shaft core portion, and a slit groove for radially deforming the through-hole, and an outer periphery of the end portion of the holder body A tightening nut that is screwed into the formed threaded portion, and by rotating the tightening nut, the collet is pushed inward of the holder body, and the diameter is reduced radially inward by the taper coupling portion. In a collet chuck tool holder for gripping a cutting tool mounted in a through hole, a cylindrical portion is extended after a tapered portion of the collet, a screw hole is formed in the cylindrical portion, and the position of the cutting tool Collet chuck tool holder, characterized in that the eye member is screwed attached. A collet chuck configured on the opposite side of the holder main body having a shank portion to be attached to the spindle end of the machine tool, the collet chuck including a tapered hole formed at the end of the holder main body, A collet having an outer shape taper to be inserted into the taper hole and a through-hole for inserting a cutting tool in the central shaft core portion, and a slit groove for radially deforming the through-hole, and an outer periphery of the end portion of the holder body A tightening nut that is screwed into the formed threaded portion, and by rotating the tightening nut, the collet is pushed inward of the holder body, and the diameter is reduced radially inward by the taper coupling portion. Collet chuck that holds the cutting tool mounted in the through hole. The collet is mounted on the tool holder, and the cylindrical part is extended from the outer tapered part of the collet, and a screw hole is formed in the cylindrical part. Rutotomoni, collet, characterized in that the cutting tool positioning member is screwed attached.

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