JP2003344002A - Micrometer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a micrometer capable of being readily manufactured, and prolonged in a service life. <P>SOLUTION: A micrometer 1 is provided with a frame 11 which is composed of an arm 111 of U shape, an anvil 112 provided at an end of the frame 11, and a spindle 12 provided at the other end capable of reciprocating to the anvil 112. The frame 11 including the anvil 112 and a sleeve 113 are integrally formed with a synthetic resin containing a nano scale material. Since the number of parts is reduced and manufacturing processes are simplified, a low cost can be attained. Since the rigidity is strengthened, coefficient of linear expansion is reduced and the attrition resistance is improved, the precision of measurement is improved and a service life is prolongated. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a micrometer.

[0002]

2. Description of the Related Art A micrometer is known as a measuring device for measuring the length of a measured portion of an object to be measured. This micrometer is configured to include a frame having a U-shaped arm, an anvil provided at one end of the frame, and a spindle screwed to the other end of the frame and capable of advancing and retracting with respect to the anvil. Has been done. With such a configuration, the size of the object to be measured can be measured from the amount of advance / retreat of the spindle when the object to be measured is sandwiched between the anvil and the spindle. In order to maintain measurement accuracy, generally, in a micrometer, the frame, anvil and spindle must have a rigidity such that they are not deformed by the pressing force of the spindle when the object to be measured is held between the anvil and the spindle. The frame, anvil and spindle are formed of an alloy such as casting as a rigid material.

[0003]

However, machining a metal into a desired form requires a great deal of time and money. Since the frame, anvil and spindle are manufactured through precision machining, problems such as complication of the production line and high cost arise.

In order to maintain the measurement accuracy, it is necessary to suppress the linear expansion within a certain range. For example, thermal expansion of the frame or spindle leads to measurement errors. Therefore, in the conventional micrometer, for example, the temperature is set to 2
The error due to linear expansion is suppressed by limiting to 0 ± 10 degrees. However, in a severe measurement environment, there is a problem that a measurement error occurs due to linear expansion.
A micrometer is a measuring instrument that is held and operated by hand. Therefore, there is a problem that a difference in linear expansion occurs due to the temperature distribution due to the heat of the hand, which easily leads to a measurement error.

When the object to be measured is held between the anvil and the spindle, if the pressing force of the spindle is strong, the anvil, the frame and the spindle are also deformed, which causes a measurement error.

An object of the present invention is to solve the problems of the prior art, to provide a micrometer which is easy to manufacture, has improved measurement accuracy, is lightweight, and has a long service life.

[0007]

In order to achieve the above object, a micrometer of the present invention comprises a frame having a U-shaped arm, an anvil provided at one end of the frame, and the other end of the frame. In the micrometer provided with a spindle that is capable of moving forward and backward with respect to the anvil, the frame is formed of a synthetic resin containing a nanoscale substance.

Generally, synthetic resins are fragile and have a large coefficient of linear expansion, but nanoscale substances (for example, carbon nanofibers) are added to a synthetic resin matrix (for example, polystyrene) to set various conditions as appropriate. Then, strengthening the rigidity,
Effects such as suppression of linear expansion, improvement of abrasion resistance, reduction of friction coefficient, and improvement of thermal conductivity can be obtained. The reason for this is not known exactly, but it is attributed to the fact that nanoscale materials form networks within synthetic resins.

Therefore, when the frame is formed of the synthetic resin containing the nanoscale substance, the rigidity of the frame is enhanced. Therefore, even when the object to be measured is held between the anvil and the spindle, the frame is not deformed by the pressing force of the spindle. As a result, the measurement accuracy of the micrometer can be improved. Since the rigidity is enhanced, the frame can be thinned.

Since the coefficient of linear expansion can be made small, errors due to linear expansion can be eliminated and precise measurement can be performed. If the linear expansion coefficient is small, precise measurement can be performed even under severe conditions without being restricted by the measurement temperature. Since the thermal conductivity is good, even when the frame is grasped by the hand for measurement, the heat of the hand is instantly diffused and the difference in expansion depending on the place does not occur. Therefore, even if it is held in the hand and used, a measurement error due to heat of the hand does not occur, and accurate measurement can be performed.

If the coefficient of friction is small and the wear resistance is improved, for example, even if the frame and the spindle are screwed together, a micrometer with little wear and a long service life can be obtained. Since it is a synthetic resin, the frame can be made lighter. Therefore, since the micrometer can be made lighter, the micrometer can be easily carried and operated. As it is a synthetic resin, it fits better in the hand than metal, and there is no concern about metal allergies.

The frame is preferably formed by injection molding a synthetic resin containing a nanoscale substance.

A synthetic resin containing a nanoscale substance has excellent molding performance, good mold transferability, and precise molding is possible even by injection molding. Furthermore, there is no need for machining or surface finishing after injection molding. Even when performing more precise surface finishing, the finishing process can be shortened. Therefore, if the frame is formed by injection molding, it can be easily manufactured. As a result, the production line and manufacturing process can be simplified, and the cost can be reduced.
At this time, when a female screw is engraved on the frame, this female screw may also be formed by injection molding. With a synthetic resin containing a nanoscale substance, a precise screw shape can be formed.

It is preferable that the anvil is integrally molded with the frame by a synthetic resin containing a nanoscale substance.

By integrally molding the anvil together with the frame with a synthetic resin containing a nanoscale substance, the number of parts and the assembling process can be reduced and the cost can be reduced. Further, since the anvil is integrally formed with the frame, the mounting error is eliminated and the measurement accuracy is improved. The rigidity is enhanced when the anvil is formed of a synthetic resin containing a nanoscale material. Therefore, even when the object to be measured is sandwiched between the anvil and the spindle, the anvil is not deformed by the pressing force. As a result, it is possible to eliminate the measurement error due to the deformation of the anvil and improve the measurement accuracy.

When the micrometer is a graduation type,
A spindle that is screwed into the main body and is capable of axially advancing and retreating by rotation, a main scale that is provided on the main body along the advance and retreat direction of the spindle, and a thimble that is provided outside the main body and rotates integrally with the spindle And a vernier scale provided along the circumference of rotation of the thimble, and at least one of the graduated scale and the vernier scale is a synthetic resin containing a nanoscale substance together with the main body or the thimble. Preferably, it is formed by injection molding.

As described above, the main scale and the subscale are formed by injection molding together with the frame and the thimble, so that the scale can be easily formed. Since the synthetic resin containing the nanoscale substance has good mold transferability and excellent molding performance, precise scales can be formed even by injection molding. Therefore, the manufacturing process can be simplified and the cost can be reduced. Conventionally, after forming a frame or thimble, the scales were engraved by machining, which may cause distortion in the frame or thimble. However, if the frame and thimble are injection-molded together with the scale with a synthetic resin containing a nanoscale substance, it is not necessary to machine the frame and the thimble after the injection molding, including the processing of the scale. Therefore, a precise frame and thimble without distortion can be obtained, and the measurement accuracy can be improved.

In the case of a digital type micrometer, the micrometer is provided with a spindle provided on the frame so as to be movable back and forth in the axial direction.
A scale having an electrode pattern in which conductive portions and non-conductive portions are alternately formed along the axial direction is provided, and the scale is
It is preferably formed by injection molding of a synthetic resin containing a nanoscale substance.

By adding a nanoscale substance and setting various conditions as appropriate, the synthetic resin can be made conductive or insulative. Therefore, for example, the spindle may be injection-molded with a synthetic resin containing a nanoscale substance as an insulator, and then the conductive electrode may be double-molded with a synthetic resin containing a nanoscale substance. Then,
The scale can be easily manufactured at low cost. Compared to the case where a scale that is formed separately from the spindle is attached, if the scale is directly attached to the spindle, the electrodes will not peel off and the electrodes will not warp, so keep the measurement accuracy accurate. You can

In the case of a digital micrometer, it is preferable that a case body having an electric circuit therein is provided, and the case body is formed of a synthetic resin containing a nanoscale substance.

According to this structure, by housing the electric circuit in the conductive case body made of the synthetic resin containing the nanoscale substance, the case body serves as an electromagnetic shield. Therefore, the internal electric circuit can be shielded from the external magnetic field and the external electric field. As a result, it is possible to prevent damage and malfunction of the electric circuit, and it is possible to maintain accurate measurement accuracy.

In the above, the nanoscale substance is
It is preferably either a carbon nanoscale material represented by carbon nanofibers or carbon nanotubes.

The carbon nanoscale substance means a nanoscale substance composed of carbon atoms such as carbon nanotubes and fullerenes, as represented by carbon nanofibers. When such a carbon nanoscale material is added to a base material such as a synthetic resin (for example, polystyrene), rigidity is increased, linear expansion is suppressed, wear resistance is improved, friction coefficient is lowered, thermal conductivity is improved, etc. The effect is obtained. In addition, if various conditions are set appropriately, it is possible to impart conductivity and insulation. Therefore, the performance of the micrometer can be improved by forming the constituent members of the micrometer, such as the frame, the anvil, and the spindle, using the synthetic resin containing the carbon nanoscale substance. Since it is a synthetic resin, it can be molded by injection molding. As a result, the manufacturing process can be simplified and the cost can be reduced.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a scale-type micrometer as a first embodiment of the micrometer of the present invention. The micrometer 1 includes a frame 11 having a U-shaped arm 111 and an anvil 112 provided at one end of the frame 11 so that the micrometer 1 can advance and retreat in the axial direction.
1 is provided with a spindle 12 provided on the other end side and a thimble 13 provided on the outer side of the frame 11 so as to be rotatable integrally with the spindle 12.

The frame 11 comprises an anvil 112 provided at one end of a U-shaped arm 111 and a sleeve 113 provided at the other end of the arm 111 and into which the spindle 12 is inserted. . This sleeve 1
A female screw (not shown) is provided on the inner periphery of 13 and is screwed with the spindle 12. On the outer surface of the sleeve 113, a main scale graduation 114 is formed along the axial direction in which the spindle 12 moves forward and backward.
Is provided. The frame 11 is a U-shaped arm 1
Including the 11, anvil 112 and the sleeve 113, it is injection-molded with a synthetic resin of polystyrene containing carbon nanofibers as a nanoscale material. The main scale 114 of the sleeve 113 during injection molding
And the internal thread is also formed at the same time.

The spindle 12 has a male screw (not shown) which is screwed into the female screw of the sleeve 113.
It is screwed to. The spindle 12 advances and retreats toward the anvil 112 by screwing rotation. Spindle 12
Is injection molded from synthetic resin containing carbon nanofibers including male threads. The thimble 13 has a cylindrical shape that covers the outside of the sleeve 113 in a cylindrical shape. On the outer surface of the thimble 13 on the one end side, a vernier scale 131 for equally dividing the circumference is provided.
Is provided. The other end of the thimble 13 is fixed to the spindle 12, and the thimble 13 and the spindle 12 are integrally rotated. The thimble 13 has a vernier scale 131.
Injection molding is performed using a synthetic resin containing carbon nanofibers.

With this structure, the following effects can be obtained. (1) Frame 11, spindle 12 and thimble 1
Since No. 3 is formed of a synthetic resin containing carbon nanofibers, it has effects of strengthening rigidity, suppressing linear expansion, improving wear resistance, lowering friction coefficient, improving thermal conductivity, and the like.

(2) Frame 11 and anvil 112
Are integrally molded with a synthetic resin containing carbon nanofibers, and the spindle 12 is formed with a synthetic resin containing carbon nanofibers. Therefore, the rigidity of the frame 11, the anvil 112, and the spindle 12 is enhanced.
As a result, the object to be measured is anvil 112 and spindle 12
The frame 11, the anvil 112, and the spindle 12 are not deformed when sandwiched by, and the measurement accuracy is improved. Further, since the rigidity of the frame 11, the anvil 112 and the spindle 12 is strengthened, the frame 11 can be thinned and the diameters of the anvil 112 and the spindle 12 can be reduced while maintaining the strength. Therefore, the micrometer can be downsized.

(3) If the coefficient of linear expansion can be made small, an error due to the linear expansion of the frame 11, the anvil 112 and the spindle 12 can be eliminated and precise measurement can be performed.
Since the coefficient of linear expansion is small, it is possible to perform precise measurement under severe conditions such as high temperature and low temperature without being restricted by the measurement temperature. (4) The frame 11 and the thimble 1 have good thermal conductivity.
Even when 3 is gripped by the hand for measurement, the heat of the hand is instantly diffused and the difference in expansion depending on the place does not occur. Therefore, even if it is held in the hand and used, a measurement error due to heat of the hand does not occur, and accurate measurement can be performed.

(5) Since it is a synthetic resin, the frame 1
1, the spindle 12 and the thimble 13 can be lightened. Therefore, since the micrometer 1 can be made lighter, the micrometer 1 is easy to carry and operate.
Can be As it is a synthetic resin, it fits better in the hand than metal, and there is no concern about metal allergies.

(6) By integrally forming the anvil 112 with the frame 11, the number of parts can be reduced. Further, by integrally forming the anvil 112 on the frame 11, there is no mounting error and the like.
The measurement accuracy can be improved. (7) The synthetic resin containing carbon nanofibers has excellent molding performance and good mold transferability. Therefore, anvil 11
2. The frame 11 can be integrally molded by injection molding including the main scale graduation 114 and the female screw. The vernier scale 131 of the thimble 13 can be integrally formed by injection molding. The spindle 12 including the external thread can be formed by injection molding. At this time, there is no need to perform machining or the like after injection molding. Therefore, the manufacturing process can be simplified and the cost can be reduced. Further, the main scale 114, the subscale 131, the spindle 12
It is possible to precisely form the male screw of the sleeve and the female screw of the sleeve 113. As a result, the measurement accuracy can be improved.

(8) The synthetic resin containing carbon nanofibers has a small friction coefficient and excellent wear resistance. Therefore, it is possible to prevent the threaded engagement between the female screw of the frame 11 and the male screw of the spindle 12 from being worn. Therefore, the service life is long and the measurement accuracy can be maintained.

(Second Embodiment) A digital micrometer will be described as a second embodiment of the micrometer of the present invention. The basic configuration is similar to that of the first embodiment, but the second embodiment differs from the first embodiment in the following points. FIG. 2 shows the spindle 12 of the second embodiment. The spindle is provided with a capacitance type scale 121 along the axial direction. This scale 121
Are conductive parts 121A and insulating parts 121 as electrode patterns.
B are formed at a predetermined pitch along the axial direction of the spindle 12. The insulating portion 121B is the spindle 12 itself, that is, the spindle 12 is formed of a synthetic resin containing carbon nanofibers as an insulator by injection molding. The conductive portion 121A is formed by injection-molding the spindle 12 and then double-molded on the spindle 12 so that conductivity is imparted with a synthetic resin containing carbon nanofibers.

In the sleeve 113 of the frame 11, a detection head 14 for capacitively coupling with the scale 121 of the spindle 12 to detect the amount of advance / retreat of the spindle 12, and an electric circuit for processing the detection value from this detection head. And 15 are provided. Here, the frame 11 is an electric circuit 1
5 is a case body, which is made of synthetic resin containing carbon nanofibers and has conductivity.

According to this structure, the effects (1), (2), (3), (4), (5), (6) and (7) of the first embodiment are obtained.
In addition to the same effect as (8), the following effect can be obtained. (9) Since the frame 11 has conductivity, the frame 1
1 serves as an electromagnetic shield, and the internal electric circuit 15 is shielded from an external magnetic field and electric field. As a result, frame 1
Since the electric circuit 15 in 1 is protected, damage and malfunction can be prevented, and the measurement accuracy can be maintained precisely.

(10) Since the spindle 12 is an insulator, static electricity will not be transmitted from the outside through the spindle 12 and penetrate into the frame 11. For example, even if the spindle 12 is brought into contact with a charged object to be measured, electricity does not propagate through the spindle 12 and enter the internal electric circuit 15. Therefore, damage and malfunction of the electric circuit 15 can be prevented, and the measurement accuracy can be maintained. (11) The electrode pattern of the scale 121 is directly formed on the spindle 12. That is, after the spindle 12 is injection-molded with a synthetic resin containing carbon nanofibers as an insulator, a conductive resin is double-molded with a synthetic resin containing carbon nanofibers. Therefore, the scale 121 can be easily manufactured at low cost. Further, as compared with the case where a scale formed separately from the spindle 12 is attached, the electrode is not peeled off or the electrode is not warped, so that the measurement accuracy can be maintained precisely.

The micrometer of the present invention is not limited to the above embodiment. Needless to say, various changes can be made without departing from the scope of the present invention. For example, in the above embodiment, the frame 1
1, the thimble 13 and the spindle 12 are all made of synthetic resin containing carbon nanofibers, but they need not necessarily be made of synthetic resin containing carbon nanofibers. For example, frame 11
Only one may be formed of a synthetic resin containing carbon nanofire bar. Further, the anvil 112 may be provided separately from the frame 11. Even in this case, the performance of the micrometer can be improved by the property of the synthetic resin containing carbon nanofibers.

In the first embodiment, the frame 11
Main scale graduation 114 and sub scale graduation 131 of thimble 13
Both of them were formed by injection molding together with the frame 11 and thimble 13, but it is not always necessary to form the main scale graduation 114 and the sub-scale graduation 131 by injection molding.
For example, the scale may be formed by laser marking after the frame 11 and the thimble 13 are injection molded. This is because the synthetic resin containing carbon nanofibers has metallic rigidity and can be machined after injection molding. Male screw of spindle 12, sleeve 11
The internal thread 3 may not be formed by injection molding, but may be formed by machining.

In the second embodiment, the scale 121 of the spindle 12 is formed so as to fit inside the frame 11, but the spindle 12 is slid by using the portion where the school 121 is formed as a sliding portion. The scale 121 may sometimes be exposed to the outside of the frame 11. This is because if the scale 121 is made of a synthetic resin containing carbon nanofibers, the scale 121 has excellent wear resistance and slidability, and therefore the scale 121 may serve as a sliding portion. With such a configuration, the length of the spindle 12 can be shortened, and as a result, the micrometer 1 can be downsized.

The nanoscale substance is not limited to carbon nanofibers, but it is possible to use a nanoscale substance such as carbon nanotube or fullerene having carbon atoms as a main constituent element. As the base material of the synthetic resin, polystyrene or polycarbonate can be used.

[0041]

As described above, according to the micrometer of the present invention, it is possible to easily manufacture, the measurement accuracy is improved, the weight is light, and the service life is long.

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment of a micrometer of the present invention.

FIG. 2 is a diagram showing a spindle according to a second embodiment of the micrometer of the present invention.

[Explanation of symbols]

1 micrometer 11 frames 12 spindles 13 thimble 15 Electric circuit 111 arm 112 Anvil 113 sleeve 114 main scale 121 scale 121A conductive part 121B insulation 131 vernier scale

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shuji Hayashida             1-20-1 Sakado, Takatsu-ku, Kawasaki City, Kanagawa Prefecture             Ceremony company Mitutoyo F term (reference) 2F061 AA16 AA24 DD03 DD04 DD09                       DD25 FF04 FF21 FF33 FF61                       FF64 FF73 GG01 GG03 GG04                       GG07 HH04 HH34 HH91 JJ01                       JJ06 JJ08 JJ41 QQ03 QQ12                       QQ14 QQ18 QQ21 QQ23 QQ32                       VV41 VV44 VV46

Claims (7)

[Claims] 1. A micrometer comprising a frame having a U-shaped arm, an anvil provided at one end of the frame, and a spindle provided at the other end of the frame so as to be capable of advancing and retracting with respect to the anvil. 2. The micrometer, wherein the frame is made of a synthetic resin containing a nanoscale substance. 2. The micrometer according to claim 1, wherein the frame is formed by injection molding of a synthetic resin containing a nanoscale substance. 3. The micrometer according to claim 1 or 2, wherein the anvil is integrally molded with the frame by a synthetic resin containing a nanoscale substance. 4. The micrometer according to any one of claims 1 to 3, wherein a spindle that is screwed into the main body and is capable of axially advancing and retreating by rotation is provided on the main body along the advancing and retracting direction of the spindle. A main scale graduation, a thimble provided outside the main body to rotate integrally with the spindle, and a sub-scale graduation provided along the rotation circumference of the thimble, wherein the main scale graduation and the sub-scale graduation are provided. At least one of the above is formed by injection molding of a synthetic resin containing a nanoscale substance together with the main body or the thimble, and a micrometer. 5. A micrometer comprising a spindle provided on a frame so as to be movable back and forth in the axial direction, wherein the spindle comprises a scale having an electrode pattern in which conductive portions and non-conductive portions are alternately formed along the axial direction. The micrometer is characterized in that the scale is formed by injection molding of a synthetic resin containing a nanoscale substance. 6. The micrometer according to claim 1, further comprising a case body having an electric circuit therein, the case body being formed of a synthetic resin containing a nanoscale substance. Characteristic micrometer. 7. The micrometer according to claim 1, wherein the nanoscale substance is either a carbon nanofiber or a carbon nanoscale substance represented by a carbon nanotube. Micrometer.