JP2000343365A - Work holding jig for machine tool and processing method - Google Patents

Abstract

(57) [Problem] To provide a work holding jig that can be firmly fixed to a machine tool even when the work has a low strength such as a thin object, has high processing accuracy, and prevents deformation during processing. provide. SOLUTION: In a machine tool for processing a work W, a holding jig 10 is used to hold the work W by bringing a tool 14 into contact with the work W and relatively moving the tool W and the tool 14. A shrink fit portion 26 for fixing the work W by shrink fit and a supported portion 25 supported by the support means 13 of the machine tool are provided. Since the work W is fixed to the support means 13 of the machine tool via the holding jig 10, there is no fear that the work W is deformed even if the chuck pressure is increased. Can be fixed firmly.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a lathe, a drilling machine,
TECHNICAL FIELD The present invention relates to a holding jig used for fixing a work to a support means of a machine tool in a machine tool such as a milling machine, an NC machine tool, and a method of processing a work using the holding jig.

[0002]

2. Description of the Related Art In the field of, for example, metal working, a cutting tool (cutting) is required to obtain a work such as a machine part.
2. Description of the Related Art A material is cut with a cutting tool such as a tool and processed into a desired shape. In a machine tool such as a lathe that performs such processing, it is general to perform processing by directly supporting a work (material) by a support means such as a chuck.

Here, a case where a workpiece is machined by a lathe, which is an example of a machine tool, will be described.
As shown in FIG. 5, a work (material) W ′ is gripped by a chuck 100 provided on a lathe so that the work W ′
Is fixed. Next, as shown in FIG. 10, while rotating the work W 'by the operation of the lathe, the cutting tool (cutti) is used.
The cutting tool 101 such as ng tool is brought into contact with the surface of the work W ′ to generate chips, thereby shaving the surface of the work W ′ and cutting the work W ′ into a desired shape. And by removing from the chuck 100,
As shown in FIG. 11, a work W ′ processed into a predetermined shape can be obtained.

[0004]

However, when a workpiece is machined by such a procedure, there are the following problems. That is, a machine tool such as a lathe is usually a method in which a work is gripped and fixed at several places (for example, three places) from around by a chuck, but when the shape of the work is complicated, the work is securely fixed by the chuck. There were cases where it was difficult to do. In addition, if the chuck pressure is increased in order to firmly fix the workpiece, the workpiece is deformed at the fixing location, the deformation remains after processing, and the workpiece may be deformed into an elliptical shape or a tapered shape. In particular, when the work is a thin material such as a thin pipe, the work is easily deformed, so that the chuck pressure cannot be increased, and it is difficult to securely fix the work.
In addition, if the work is thin, the work is easily deformed during machining, and the work may be damaged due to biting of the cutting tool, or the work may be cut (relieved) to reduce the amount of work cut, resulting in reduced machining accuracy and processing time. , Resulting in an increase in man-hours.

An object of the present invention is to provide a work holding jig which can be firmly fixed to a machine tool even when the work has a low strength such as a thin object, has a high processing accuracy, and can prevent deformation during the processing. Another object of the present invention is to provide a method of processing a work using the work holding jig.

[0006]

In order to achieve this object, a first aspect of the present invention relates to a machine tool for machining a workpiece by bringing a tool into contact with a workpiece and relatively moving the tool with the workpiece. A holding jig used for holding a work, comprising: a shrink-fit portion for fixing the work by shrink-fitting; and a supported portion supported by a support means of the machine tool. I have.

In the work holding jig of the first aspect, the work is shrink-fitted by the shrink-fitting portion, the supported portion is supported by the support means of the machine tool, and the work is held through the holding jig. The work is fixed to the support means of the machine. Then, the workpiece is machined by bringing the tool into contact with the workpiece and moving the workpiece and the tool relatively. Then, after processing is completed, the processed work can be obtained by removing the work from the shrink-fit portion of the holding jig.

According to the work holding jig of the first aspect,
Since the work is fixed to the support means of the machine tool via the holding jig, there is no concern that the work will be deformed even if the chuck pressure is increased, and even thin work can be firmly fixed by shrink fitting. can do. In addition, since the work can be machined with the work firmly fixed, there is no risk of the work being deformed during machining, and even if the work is thin, the work will not be damaged by the bite of the cutting tool.
Also, there is no deformation (runaway) of the workpiece, and the machining accuracy is improved, and there is no fear that the machining time and man-hours are unnecessarily increased.

In the work holding jig of the first aspect,
Machine tools include, for example, lathes, drilling machines, milling machines, N
C machine tools, broaching machines, etc. For a machine tool such as a lathe that rotates and rotates a work and a tool relative to each other, the center axis of the holding jig in a state where the work is shrink-fitted as described in claim 2, for example. And the central axis of the workpiece is preferably substantially coincident. Then, when the work is fixed to the lathe or the like, the center axis of the work substantially coincides with the center axis of the main shaft of the lathe or the like, so that the work can be processed smoothly.

[0010] As described in claim 3, the shrink-fit portion is formed, for example, by inserting a part of the holding jig into a hollow portion formed in the work and forming the work on an outer peripheral surface of the holding jig. Wherein the supported portion projects outward from the cavity while the work is shrink-fitted to the shrink-fitting portion, and is supported by the support means of the machine tool. Configuration. In this case, a part (shrink fit) of the holding jig is inserted into the cavity while the work is heated and expanded.
Next, the work is cooled and shrunk, and the work is shrink-fitted on the outer peripheral surface (shrink fit portion) of the holding jig. When the workpiece is shrink-fitted in this way, the supported part protruding outside from the cavity of the workpiece is supported by the supporting means of the machine tool, thereby supporting the machine tool via the holding jig. The work can be fixed to the means.

In the case where the work is shrink-fitted on the outer peripheral surface of the shrink-fit portion of the holding jig as in the third aspect, the holding jig is more than the work. It is preferable to use a material having a small coefficient of thermal expansion. Then, if the work and the work are heated together when the work is removed from the shrink fit of the work, the work will expand more than the work. The work can be easily removed from the shrink fit.

In the case where the work is shrink-fitted on the outer peripheral surface of the shrink-fitting portion of the holding jig, the outer diameter of the holding jig in the shrink-fitting portion is set at room temperature. 0.01 to 0.02 than the inner diameter of the cavity of the work
mm is preferred. If the outer diameter of the shrink-fit part of the holding jig is less than 0.01 mm larger than the inner diameter of the cavity of the work, the adhesion between the work and the holding jig will be weak and the work will be removed from the holding jig during processing. There is a possibility of slipping off. On the other hand, if the outer diameter of the shrink-fit portion of the holding jig is larger than the inner diameter of the cavity of the work by 0.02 mm, the work shrinks when the holding jig is removed, and the dimension becomes out of tolerance. .

In the case where the work is shrink-fitted on the outer peripheral surface of the shrink-fit portion of the holding jig, a hole for circulating air is formed inside the holding jig. It is preferred that Then, the heat radiation of the holding jig is improved, and for example, the holding jig heated when the work is removed from the shrink fit portion is cooled in a short time.

On the other hand, for a machine tool such as a broaching machine for machining the inner surface of a work, for example,
As described in the above, the shrink-fit portion is configured to insert the work into a cavity formed in the holding jig and shrink the work on the inner peripheral surface of the holding jig. Is preferred. In this case, the work is inserted into the cavity (shrink fit) with the holding jig heated and expanded. Next, the holding jig is cooled and contracted, and the work is shrink-fitted on the inner peripheral surface (shrink fit portion) of the holding jig. In such a state where the work is shrink-fitted, by supporting the supported portion on the support means of the machine tool, it is possible to fix the work to the support means of the machine tool via the holding jig. Become.

In the case where the work is shrink-fitted on the inner peripheral surface of the shrink-fit portion of the holding jig according to the seventh aspect, the holding jig may be moved from the workpiece by the work. It is also preferable that the material be made of a material having a large coefficient of thermal expansion. Then, if the work and the work are heated together when the work is removed from the shrink fit of the work, the work will expand more than the work. The work can be easily removed from the shrink fit.

In the case where the work is shrink-fitted on the inner peripheral surface of the shrink-fit portion of the holding jig, the inner diameter of the cavity formed in the holding jig is set at room temperature. Is preferably smaller by 0.01 to 0.02 mm than the outer shape of the work. If the inner diameter of the shrink-fit part of the holding jig is smaller than the inner diameter of the cavity of the work by less than 0.01 mm, the adhesion between the work and the holding jig becomes weak, and the work comes off the holding jig during processing. There is a possibility that idle.
On the other hand, if the inner diameter of the shrink fit portion of the holding jig is smaller than the inner diameter of the hollow portion of the work by 0.02 mm, the work expands when the holding jig is removed, and the dimensions are out of tolerance. .

The invention of claim 10 is the invention of claims 1, 2, 3,
A method of processing a work using a work holding jig for a machine tool of any one of 4, 5, 6, 7, 8, and 9,
The work is shrink-fitted by the shrink fit portion of the holding jig, the supported portion is gripped by the support means of the machine tool, and the work is supported by the support means of the machine tool via the holding jig. The method includes a step of fixing, and a step of processing the work by bringing a tool into contact with the work and relatively moving the work and the tool.

According to the processing method of the tenth aspect, by fixing the work to the support means of the machine tool via the holding jig, the work is deformed through the holding jig by shrink fitting without deforming the work. The work can be firmly fixed to the machine. In addition, there is no fear that the work is deformed during the processing, and even when the work is a thin work, the processing can be performed with high accuracy, and the processing time and man-hours do not needlessly increase.

[0019]

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In the following embodiment, a workpiece W is used by using a lathe as an example of a machine tool.
An example in which is machined will be described.

FIG. 1 is a sectional view of a work W to be machined in the embodiment of the present invention. In FIG.
Is shown in the state of the material that has not been processed yet.
The work W is, for example, steel, SUS, copper, aluminum,
It may be made of a metal material such as various alloys, and the size may be any as long as it can be processed by a lathe. In this example, the work W
Has the shape of a hollow cylinder. In the state of the unprocessed material, the length L of the work W is the same size as the length (e + f + g) of the work W after finishing the work.
The outer diameter D is about 1 mm longer at each end than the maximum outside diameter of the work W after the processing is completed, for example, 5 m.
m, and the inner diameter H is smaller than the minimum inner diameter (c) of the work W after finishing the machining.

First, as shown in FIG. 2, the inner surface of the work W is cut and processed, and a large diameter portion 1 having an inner diameter a and a length e, an inner diameter b, a middle diameter portion 2 having a length f, an inner diameter c, and a length g are provided. The hollow portion 4 including the small diameter portion 3 is formed.

Next, a holding jig 10 is prepared. First, FIG.
A material 11 as shown in FIG. The material 11 is longer than the length (e + f + g) of the work W by, for example, about 40 mm, and has a cylindrical shape whose outer diameter is larger than the inner diameter a of the large diameter portion 1 of the work W. A hole 12 is formed in the base end surface of the material 11 (the left end surface of the material 11 in FIG. 3), and air can flow through the hole 12. As the material of the raw material 11, for example, a material having a small coefficient of thermal expansion such as SKD-11 and DC-53 specified in JIS is used.

As shown in FIG. 4, the base end side of the material 11 (the left end side of the material 11 in FIG. 4) is a supported portion 25, and the supported portion 25 is a chuck 13 provided on a lathe.
While supporting (gripping) the material 11 and rotating the material 11 by the operation of the lathe, cutting tool (cutting to
ol) or the like, the cutting tool 14 is brought into contact with the surface, and the outer peripheral surface of the material 11 is cut to form the holding jig 10. As shown in FIG. 4, a large-diameter portion 21 having an inner diameter A and a length E, a middle-diameter portion 2 having an inner diameter B and a length F are provided on the outer peripheral surface of the holding jig 10.
2. By providing a small diameter portion 23 having an inner diameter C and a length G,
The front end side of the holding jig 10 (the right end side of the holding jig 10 in FIG. 4) is formed in the shrink fit portion 26. In this case, the large diameter part 2
The inner diameter A of the large diameter portion 1 in the cavity 4 on the inner surface of the work W described above with reference to FIG. In addition, the medium diameter portion 22
Is 0.01 to 0.02 m at room temperature, which is smaller than the inner diameter b of the middle diameter portion 2 in the hollow portion 4 on the inner surface of the work W.
m. The inner diameter C of the small diameter portion 23 is
The inner diameter c of the small-diameter portion 3 in the hollow portion 4 on the inner surface is made larger by 0.01 to 0.02 mm at room temperature. Also,
The length E of the large diameter portion 21 is preferably longer than the length e of the large diameter portion 1 in the hollow portion 4 on the inner surface of the work W, for example, by about 40 mm. Further, the length F of the middle diameter portion 22 and the length G of the small diameter portion 23 are equal to the inner diameter f of the middle diameter portion 2 and the length g of the small diameter portion 3 in the hollow portion 4 on the inner surface of the work W, respectively. The depth of the hole 12 (depth from the base end face of the material 11) is
It is preferable to make the depth smaller than the sum of the length E of the large diameter portion 21 and the length F of the middle diameter portion 22, and to set the inner diameter K of the hole 12 to be smaller than the inner diameter C of the small diameter portion 23.

Further, the holding jig 10 obtained by cutting in this manner may be further quenched and polished.

Next, the work W described with reference to FIG. 2 is expanded by heating. In this case, heating may be performed by a heater or the like, or may be performed by a burner. Heating temperature is 2
The temperature may be about 00 ° C., and the heating time is preferably about 15 to 20 minutes. If the temperature is too high, the surface of the work W is discolored, which is not preferable.

With the work W expanded in this way, the shrink fit 26 of the holding jig 10 described above with reference to FIG. 4 is inserted into the cavity 4 on the inner surface of the work W described with reference to FIG. .
In this case, since the work W has increased due to thermal expansion,
Shrink fit 26 can be easily inserted into cavity 4. In addition, shrink fit 2
6 is desirably inserted.

Next, the work W is cooled and contracted.
The work W is shrink-fitted on the outer peripheral surface of the shrink-fit portion 26 as shown in FIG. The cooling is performed, for example, by first cooling the atmosphere and then cooling the water. Thus, when the work W is shrink-fitted into the shrink-fitting portion 26 of the holding jig 10, the shrink-fitting portion 2
6, a large diameter part 21, a medium diameter part 22, and a small diameter part 23
Are firmly adhered to the large-diameter portion 1, the medium-diameter portion 2, and the small-diameter portion 3 formed in the hollow portion 4 of the work W from the inside, respectively, and the work W is firmly fixed to the holding jig 10. You.

Also, the work W is held by the holding jig 10 as described above.
In the shrink-fitted state, the supported portion 25 formed on the base end side of the holding jig 10 (the left end side of the holding jig 10 in FIG. 5) is, for example, 40 mm from the hollow portion 4 of the work W.
Since the projecting portion protrudes to the outside, the supported portion 25 can be firmly grasped by the chuck 13, and can be firmly fixed via the holding jig 10 without deforming the work W.

Next, the outer surface of the work W is cut by bringing the cutting tool 14 such as a cutting tool into contact with the surface of the work W while rotating the work W by operating the lathe. When performing the lathe processing in this manner, the work W can be processed while being firmly held from the inner surface side, so that there is no fear that the work W is deformed during the processing, and even if the thin work W is processed, the cutting tool 14 can be used. Work W by biting into
Will not be damaged. Further, during the processing, the deformation (runaway) of the work W is also eliminated, the processing accuracy is improved, and there is no fear that the processing time and the number of steps are unnecessarily increased. During lathing,
Since the center axis of the work W and the center axis of the holding jig 10 substantially coincide with the center axis (rotation center) of the main axis of the lathe,
The cutting of the work W is performed smoothly.

After completion of the cutting, the work W is heated and expanded again, and the work W is removed from the shrink fit portion 26 of the holding jig 10. In this case, only the work W may be heated and expanded, but if the holding jig 10 is made of a material having a smaller thermal expansion coefficient than the work W, the work W and the holding jig 10 may be heated integrally. . Then, the work W expands more than the holding jig 10, and the work W can be easily removed from the shrink fit portion 26 of the holding jig 10. Thus, as shown in FIG. 6, it is possible to obtain a work W processed into a desired shape. The holding jig 10 can be reused.

Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment. For example, the holding jig of the present invention can be used for other machine tools such as a drilling machine other than a lathe, a milling machine, an NC machine tool, and a broaching machine.

The holding jig 50 shown in FIG.
The workpiece W is fixed to the shrink fit portion 55 formed on the inner surface of the work by shrink fitting. A cylindrical space portion 51 is formed in the holding jig 50, and a hollow cylindrical work W is fixed in close contact with the inner surface (shrink fit portion 55) of the space portion 51. On the outer peripheral surface of the holding jig 50, a supported portion 56 to be gripped by the support means of the machine tool is formed. When the work W is fixed to the holding jig 50 as described above, first, the work W is inserted into the space 51 while the holding jig 50 is heated and expanded.
After the insertion, the holding jig 50 is cooled and contracted, so that the work W is placed on the inner surface (shrink fit portion 55) of the space 51.
Can be fixed by closely contacting the outer peripheral surfaces thereof. When removing the work W from the holding jig 50, the holding jig 5
The workpiece W can be taken out of the space 51 by heating the 0 and expanding it. As described above, the work W is fixed to the inner surface (shrink fit portion 55) of the holding jig 50 by shrink fitting. In order to fix the work W to the inner surface (shrink fit portion 55) of the holding jig 50 by shrink fitting, the holding jig is preferably made of a material having a larger thermal expansion coefficient than the work. In addition, the inner diameter of the space 51 formed in the holding jig 50 is smaller than the outer diameter of the workpiece W by 0.0.
It is preferably smaller by 1 to 0.02 mm.

FIG. 8 shows that the supported portion 56 of the holding jig 50 described in FIG. 7 is gripped by a machine tool 57 such as a broaching machine.
By shrink-fitting the work W on the inner surface (shrink fit portion 55) of the holding jig 50, the work W
Is fixed to a machine tool 57, and a cutting tool 58 such as a broach is fixed.
Indicates a state in which the inner surface of the work W is being cut. As described above, by fixing the work W to the inner surface of the holding jig 50 by shrink fitting, the work W can be formed as shown in FIGS.
Similar to the embodiment described in the above, there is no fear that the work W is deformed during the processing, and even if the thin work W is processed, the work W is not damaged by the cutting tool 58 biting. In addition, during processing, deformation (runaway) of the workpiece W is eliminated, processing accuracy is improved, and there is no fear that processing time and man-hours are unnecessarily increased.

[0034]

EXAMPLE A work was actually cut in accordance with the procedure described above with reference to FIGS. Outer diameter φ100mm, inner diameter φ65
A thin pipe as shown in FIG. 6 was prepared by cutting using a stainless steel pipe having a length of 140 mm and a length of 140 mm. First, fix the material to the chuck provided on the lathe,
The inner surface was cut by rotation. The inner surface was machined as described with reference to FIG. 2, and a = φ90 mm, b = φ80 mm, c =
Finished to a size of φ70 mm. Next, a holding jig shown in FIG. 4 was prepared. The outer diameter of the shrink fit part of the holding jig
A = φ90.15mm, B = φ80.15mm, C
= 70.015 mm. The material of the holding jig was JIS SKD-11. Next, the work was heated with a heater, and the temperature was increased to 20 over 15 minutes while checking with a contact thermometer.
0 ° C. Next, insert the holding jig into the cavity of the work,
The work and the holding jig are both air-cooled and then water-cooled.
The work and the holding jig were brought into close contact. Next, after cooling, the outer surface of the work was processed as described in FIG. Next, the work and the holding jig were reheated, and the work was removed from the holding jig. The condition of reheating was the same as above, heating with a heater, and keeping the temperature at 200 ° C. over 15 minutes while checking with a contact thermometer. The thickness of the thin portion of the processed work was 0.4 mm, which was a perfect circle.

Next, as a comparative example, the material was directly held by a chuck without using a holding jig, and cutting was performed in the order of outer surface processing and inner surface processing. As a result, the thin part was deformed and became an elliptical work.

[0036]

According to the first to tenth aspects, the work is fixed to the support means of the machine tool via the holding jig.
Even if the chuck pressure is increased, there is no concern that the workpiece will be deformed.
Even thin workpieces can be firmly fixed by shrink fitting. In addition, since the work can be machined while the work is firmly fixed, there is no fear that the work will be deformed during the processing. Even if the work is thin, it will not be damaged by the bite of the tool, ) Is eliminated, processing accuracy is improved, and there is no fear that processing time and man-hours are unnecessarily increased.

[Brief description of the drawings]

FIG. 1 is a sectional view of a work in a state of a raw material that has not been processed.

FIG. 2 is a cross-sectional view of a work whose inner surface is cut.

FIG. 3 is a side view of a material for forming a holding jig.

FIG. 4 is a side view of a holding jig supported by a chuck of a lathe.

FIG. 5 is a sectional view of a work shrink-fitted to a holding jig.

FIG. 6 is a cross-sectional view of the work after processing.

FIG. 7 is a cross-sectional view of a holding jig in which a work is shrink-fitted on an inner surface.

FIG. 8 is an explanatory view showing a state where a work shrink-fitted on the inner surface of a holding jig is being machined.

FIG. 9 is an explanatory diagram of a conventional technique.

FIG. 10 is an explanatory diagram of a conventional technique.

FIG. 11 is an explanatory diagram of a conventional technique.

[Explanation of symbols]

 W Work 10 Holding jig 12 Hole 13 Chuck 14 Cutting tool 25 Supported part 26 Shrink fit part

Claims (10)

[Claims] 1. A holding jig used for holding a work in a machine tool for processing the work by bringing the tool into contact with the work and relatively moving the tool and the tool. A work holding jig for a machine tool, comprising: a shrink-fit portion for fixing the work by means of a support; and a supported portion supported by support means of the machine tool. 2. The apparatus according to claim 1, wherein a center axis of said holding jig substantially coincides with a center axis of said work when said work is shrink-fitted.
A workpiece holding jig for a machine tool according to claim 1. 3. The shrink-fitting part is configured to insert a part of the holding jig into a cavity formed in the work and shrink the work on the outer peripheral surface of the holding jig. The supported portion is configured to protrude outside from the hollow portion in a state where the work is shrink-fitted to the shrink-fit portion, and is supported by the support means of the machine tool. A work holding jig for a machine tool according to claim 1 or 2. 4. The work holding jig for a machine tool according to claim 3, wherein said holding jig is made of a material having a smaller thermal expansion coefficient than said work. 5. The work according to claim 4, wherein the outer diameter of the holding jig in the shrink-fitting part is larger by 0.01 to 0.02 mm than the inner diameter of the cavity of the work at room temperature. Work holding jig for machine. 6. The holding jig is provided with a hole for flowing air inside the holding jig.
Or, a work holding jig for a machine tool according to 5. 7. The shrink-fit portion is configured to insert the work into a cavity formed in the holding jig and shrink the work on an inner peripheral surface of the holding jig. 3. A workpiece holding jig for a machine tool according to claim 1, wherein 8. The work holding jig for a machine tool according to claim 7, wherein the holding jig is made of a material having a larger thermal expansion coefficient than the work. 9. An inner diameter of a cavity formed in the holding jig is 0.01 to 0.01 at a normal temperature relative to an outer shape of the work.
9. The method according to claim 7, wherein the distance is 0.02 mm smaller.
Work holding jig for machine tools. 10. The method according to claim 1,2,3,4,5,6,7,
8. A method of processing a work using a work holding jig for a machine tool according to any one of 8 and 9, wherein the work is shrink-fitted to a shrink-fit portion of the holding jig, and the supported portion is Fixing the work to the support means of the machine tool via the holding jig by holding the support means of the machine tool;
Machining the work by bringing a tool into contact with the work and relatively moving the work and the tool.