JPH09155609A - Collet and sleeve and tool holder therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve oscillation precision of a machined hole. SOLUTION: A collet 21 is provided with a guide part 26 and changed diameter parts 23 and 24. The guide part 26 has approximately the same diameter as that of the guide surface 29 of a sleeve 28, and consists of a surface paralleling an axis. The changed diameter parts 23 and 24 are formed in succession to the guide part 26. The guide surface 29 of the sleeve 28 are formed in a shape conforming to that of the guide part 26 of the collet 21. Namely, a positioning reference surface between the collet 21 and the sleeve 28 constitutes of the guide part 26 and the guide surface 29. When the collect 21 is fixed at the sleeve 28, the collet 21 is slidably guided in parallel to the sleeve 28 and positioning and fixing are carried out with high precision without the occurrence of microinclination. This constitution prevents fixing of a drill in a microinclination state and improves oscillation precision of a machined hole.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for positioning and fixing a tool or a work by using a collet.

[0002]

2. Description of the Related Art When fixing a drill to a rotary shaft, a method is well known for positioning by interposing a collet between a sleeve provided on the rotary shaft and the drill. As shown in FIG. 5, the collet 1 has a substantially cylindrical shape, and a drill, which is a member to be fixed, is inserted into the inner peripheral portion 2. Further, the outer peripheral portion of the collet 1 is composed of only the tapered surfaces 3 and 4 whose diameter is reduced toward the end. A plurality of slits 5 reaching the inner peripheral portion 2 are formed on the tapered surfaces 3 and 4, and the collet 1 can be reduced in diameter by reducing the distance between the slits. Therefore, in this description, the tapered surfaces 3 and 4 are referred to as variable diameter portions.

The collet 1 is fitted into a sleeve 8 fixed to a rotary shaft 7 together with a drill 6 as shown in FIG.
Further, the lock nut 9 is tightened with the sleeve 8. Further, the distal end opening 10 of the sleeve 8 and the inner peripheral surface 11 of the lock nut 9 are tapered so that they respectively come into close contact with the variable diameter portions 3, 4 of the collet 1. Then, as the tightening amount of the lock nut 9 is increased, the pressure applied to the variable diameter portions 3 and 4 is increased, and the collet 1 is reduced in diameter to grip the drill 6. In addition, the variable diameter portion 4 formed of the tapered surface of the collet 1
Is guided by the tapered tip opening 10 of the sleeve 8 to cause slippage between the tapered surfaces, self-correcting the center position and inclination of the collet 1, and centering the drill 6. Has become. In addition, a pin 12 that penetrates the sleeve 8 and reaches the collet 1 is provided to prevent the collet 1 from rotating.

[0004]

The structure for positioning and fixing the drill having the above-mentioned structure has the following drawbacks. First, when the center of the drill 6 is positioned, the collet 1 and the sleeve 8 are positioned by bringing only the tapered surfaces into contact with each other, so that there is no universal positioning reference surface between them and Inclination tends to occur in the range of angles. Moreover, in the state where a slight angle of inclination is generated, the frictional force of the contact surface and the force for self-correcting the inclination are balanced, slippage between the tapered surfaces is suppressed, and the drill 6 remains inclined at a small angle. It was sometimes fixed. If you rotate the drill 6 in this state,
There is a problem that the runout as shown by A in FIG. 6 occurs and the runout accuracy of the machined hole is reduced.

Further, since the outer peripheral portion of the collet 1 is composed of only the variable diameter portions 3 and 4 formed of the tapered surface, the slit 5 cannot be positioned in the outer peripheral portion when machining. It was difficult to obtain a predetermined processing accuracy. Further, for example, when the variable diameter portion 3 is clamped to form the slit 5 in the variable diameter portion 4 after forming the slit 5 in the variable diameter portion 3, the variable diameter portion 3 has already been provided with the slit 5. It was elastically deformed, making positioning and fixing for processing difficult.

The present invention has been made in view of the above problems, and an object thereof is to improve the workability of the collet and to improve the positioning accuracy when positioning the collet on the sleeve. is there. Further, by using the collet and the sleeve as a tool holder, it is possible to improve the runout accuracy of the machined hole.

[0007]

A collet according to the present invention for solving the above problems is used by interposing between a sleeve and a fixed member, and the collet is a guide portion and a variable diameter portion. And the guide portion is formed of a surface having substantially the same diameter as the distal end opening portion of the sleeve and parallel to the axis, and the variable diameter portion is provided continuously to at least one end portion of the guide portion. It is characterized by being.

Further, a sleeve according to the present invention for solving the above-mentioned problems supports the collet, and the tip opening into which the collet is fitted has a shape that follows the guide portion of the collet. Has a guide surface that
Further, it is characterized in that it has a pressing portion for applying a radial pressure to the variable diameter portion of the collet.

Further, a tool holder according to the present invention for solving the above problems is characterized by including the collet and the sleeve.

By the way, the collet according to the present invention has a guide portion which has a diameter substantially the same as that of the distal end opening of the sleeve and which is constituted by a surface parallel to the axis, and is used when the collet is machined. Used as a positioning reference plane.

Further, in the sleeve according to the present invention, a guide surface having a shape similar to the guide portion of the collet is provided at the tip opening portion into which the collet is fitted, and the guide surface and the guide portion of the collet are provided. And form a positioning reference surface between the sleeve and the collet.

Further, the tool holder according to the present invention comprises the collet and the sleeve, and constitutes a positioning reference plane between the sleeve and the collet.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings. In the figure, the same or corresponding parts as those of the conventional example are designated by the same reference numerals, and detailed description thereof will be omitted.

FIG. 1 shows a sectional view of a tool holder 20 according to a first embodiment of the present invention. The collet 21 is fitted together with the drill 6 into the sleeve 28 fixed to the rotary shaft 7, and is further fastened to the sleeve 28 with the lock nut 9. By the way, the collet 21 used here has a structure as described below.

As shown in FIG. 2, the collet 21 has a substantially cylindrical shape, and the drill 6 (FIG. 1), which is a member to be fixed, is inserted into the inner peripheral portion 2. The outer peripheral portion of the collet 21 has a guide portion 26 and variable diameter portions 23, 24. The guide portion 26 has substantially the same diameter as the tip end opening portion 29 of the sleeve 28 shown in FIG. 1, and is configured by a single-diameter cylindrical surface that is a surface parallel to the axis of the rotating shaft 7. The variable diameter portions 23 and 24 are connected to the guide portion 26.
Are formed continuously at both ends of the. The variable diameter portions 23 and 24 are
A plurality of slits 25 (see FIG. 3) are formed, which are formed by a tapered surface whose diameter decreases toward the end and reach the inner peripheral portion 2 from the outer peripheral portion. The diameter can be elastically reduced or expanded by changing the interval between the slits.

Next, the sleeve 28 will be described. FIG.
As shown in FIG.
In order to fit with the guide portion 26, the guide portion 26 has a single-diameter cylindrical surface, following the guide portion 26. That is, the tip opening
Reference numeral 29 denotes a surface that guides the collet 21 without tilting, and the tip opening portion 29 is referred to as a guide surface in the following description. When setting the diameter of this guide surface 29, the guide portion 26 of the collet 21
It is desirable to set the fitting dimensions so that can slide. Further, the sleeve 28 has a tapered surface which is continuous with the guide surface 29 and whose diameter is gradually reduced. This tapered surface is referred to as a pressing portion 30 in the following description.

In the state shown in FIG. 1, the inner peripheral surface of the lock nut 9 is increased each time the lock nut 9 is closed.
The variable diameter portion 23 of the collet 21 is pressed at 11. Then, the collet 21 is pushed downward in FIG. 1, and the variable diameter portion 24 is pressed against the pressing portion 30 of the sleeve 28. At this time, the variable diameter part of collet 21
23 is the inner peripheral surface 11 of the lock nut 9
The pressing portion 30 of the sleeve 28 applies a pressure in the diameter reducing direction 24 to firmly clamp the drill 6. At this time, since the guide portion 26 of the collet 21 is slidably guided by the guide surface 29 of the sleeve 28 in parallel to the axis of the rotating shaft 7,
The drill 6 can be positioned and fixed with high accuracy without causing a slight inclination.

Further, although the collet 21 is prevented from rotating with respect to the sleeve 28 by the pin 12, as another example, it is replaced with the pin 12 by forming splines, serrations or the like on the guide portion 26 and the guide surface 29. You can also

By the way, since the guide portion 26 of the collet 21 is constituted by a surface parallel to the axis line such as a cylindrical surface having a single diameter, it can be used as a reference surface when processing the collet 21. . Further, since the slit 25 is not formed in the guide portion 26, the collet 21 can be reliably clamped without being elastically deformed by an external force. Therefore, it is possible to perform positioning and fixing when processing the slit 5 by the guide portion 26, and it is possible to easily perform high-precision processing.

The operation and effect obtained from the first embodiment of the present invention having the above configuration are as follows. Collet
21 has a guide portion 26 having a single diameter and a cylindrical surface having substantially the same diameter as the guide surface 29 of the sleeve 28, and positioning the collet 21 between the guide portion 26 and the guide surface 29. Thus, highly accurate positioning can be performed. Further, the guide portion 26 can also be used as a positioning reference surface when processing the collet 21 itself, and the workability and processing accuracy of the collet 21 can be improved.

Further, the tip end opening of the sleeve 28 is a guide surface 29 having a shape following the guide portion 26 of the collet 21,
The guide surface 29 and the guide portion 26 form a positioning reference surface between the sleeve 28 and the collet 21. Since both the guide surface 29 and the guide portion 26 are surfaces parallel to the axis of the rotary shaft 7, the collet 21 is slidably guided in parallel to the sleeve 28 and does not cause a minute inclination, thus achieving high accuracy. Can be positioned and fixed to.

Therefore, the collet 21 and the sleeve 28 are
A tool holder 20 comprising a sleeve 21 and a collet
Since the positioning between the 28 can be performed with high accuracy, there is no possibility that the drill 6 is fixed while being tilted by a small angle, and the runout accuracy of the machined hole can be improved.

Next, a second embodiment of the present invention will be described with reference to FIG. The second embodiment is an application of the present invention to a jig for positioning and fixing a work.

FIG. 4 shows a sectional view of a main portion of a jig 40 according to the second embodiment of the present invention. The jig 40 has the following structure in order to position and fix the workpiece W that is the member to be fixed. The main body 41 has a sleeve 42, and a tip end opening portion of the sleeve 42 is a guide surface 43 having a single diameter. An elastic member such as a disc spring is provided on the bottom surface 44 of the guide surface 43.
45 is arranged, and the collet 46 is slidably fitted to the guide surface 43. Further, a taper cone 48 is fixed to a tip end portion of a draw bar 47 penetrating the sleeve 42 and the collet 46, and the taper cone 48 pushes down the collet 46. Workpiece W, the reference hole W _H is engaged and the collet 46 is placed on the support member 49 fixed to the body 41. The upper surface of the support member 49 is formed as a horizontal reference plane.

Here, the collet 46 according to the present embodiment will be described. The collet 46 has a substantially cylindrical shape, and has a guide portion 50 and a variable diameter portion 51. The outer periphery of the guide portion 50 has a diameter substantially the same as the guide surface 43 of the sleeve 42, and the draw bar
It is composed of a surface (a cylindrical surface of a single diameter or the like) parallel to the central axis of the. Further, the inner peripheral portion 52 of the guide portion 50 has a diameter such that the draw bar 47 can slide. Variable diameter part 51 of collet 46
Has a diameter substantially the same as that of the guide portion 50, and the inner peripheral portion 53 is a tapered surface whose diameter increases toward the upper end. Further, like the collet 21 according to the first embodiment, the variable diameter portion 51 has a plurality of slits (not shown) formed therein, and the distance between the slits is changed to elastically reduce or expand the diameter. Is something that can be done.

The taper cone 48 is fixed to the draw bar 47 by bolts 54, and the outer peripheral portion 55 is a collet.
The tapered surface has a diameter increasing toward the upper end so as to correspond to the inner peripheral portion 53 of 46.

When the draw bar 47 is pulled down, the outer peripheral portion 55 of the taper cone 48 and the inner peripheral portion 53 of the collet 46 come into close contact with each other, and the collet 46 descends while the guide portion 50 is slidably guided by the guide surface 43. At this time, the disc spring 45 arranged below the collet 46 functions to prevent the collet 46 from descending. Therefore, the pressing from the outer peripheral portion 55 of the taper cone 48 to the inner peripheral surface 53 of the collet changing diameter portion 51 also works in the direction of expanding the diameter changing portion 51, so that the changing diameter portion 51 of the collet 46 serves as a reference hole for the workpiece W. W
_The workpiece W is positioned and fixed in close contact with _H.

That is, in the second embodiment,
The outer peripheral portion 55 of the taper cone 48 and the disc spring 45 respectively function as the pressing portion 30 and the lock nut 9 in the first embodiment.

The operational effects obtained from the second embodiment of the present invention having the above structure are as follows. Collet
The guide portion 50 of 46 is slidably guided by the guide surface 43 of the sleeve 42 and descends straight along the center axis of the draw bar 47, so that the center position is not displaced and the work W can be positioned with high accuracy. It can be carried out. Also collet
Since the guide portion 50 of 46 has a cylindrical shape with the same diameter, it can be used as a processing reference surface when processing the collet 46 itself, and the processing accuracy of the collet 46 is the same as that of the first embodiment. Can be improved.

[0030]

According to the present invention, the following effects are obtained. When a collet is formed between the sleeve and the member to be fixed, a guide portion having a diameter substantially the same as that of the tip opening of the sleeve and parallel to the axis is formed on the collet. By setting the positioning reference surface on this guide portion, the workability and processing accuracy of the collet can be improved.

Further, a guide surface having a shape similar to the guide portion of the collet is provided at the tip end opening of the sleeve, and the guide surface and the guide portion of the collet are arranged between the sleeve and the collet. Since the positioning reference surface is formed, when the collet is fixed to the sleeve, the collet is slidably guided in parallel with the sleeve, and the positioning and fixing can be performed with high precision without causing a slight inclination.

Further, since the tool holder according to the present invention is provided with the collet and the sleeve and constitutes the positioning reference plane between the sleeve and the collet, the drill can be fixed at a slight angle. Without, it is possible to improve the runout accuracy of the processed hole.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a tool holder according to a first embodiment of the present invention.

FIG. 2 is a perspective view of the collet shown in FIG.

FIG. 3 is a side view of a main part of the collet shown in FIG.

FIG. 4 is a sectional view showing a jig for positioning and fixing a work according to a second embodiment of the present invention.

FIG. 5 is a perspective view showing a conventional collet.

FIG. 6 is a sectional view showing a conventional tool holder.

[Explanation of symbols]

 6 Drill 20 Tool holder 21 Collet 23 Variable diameter part 24 Variable diameter part 26 Guide part 28 Sleeve 29 Guide surface 30 Pressing part

Claims (3)

[Claims] 1. A collet which is used by being interposed between a sleeve and a fixed member, wherein the collet has a guide portion and a variable diameter portion, and the guide portion has substantially the same diameter as the tip opening portion of the sleeve. A collet characterized in that it is constituted by a surface parallel to the axis line and the variable diameter portion is provided continuously to at least one end portion of the guide portion. 2. A sleeve for supporting a collet, comprising:
The tip opening into which the collet is fitted has a guide surface having a shape that follows the guide portion of the collet, and further has a pressing portion that applies a radial pressure to the variable diameter portion of the collet. A sleeve characterized by that. 3. The collet according to claim 1 and claim 2.
A tool holder comprising: