JPS6365064A - Micrometer - Google Patents

Abstract

PURPOSE:To improve the durability and reliability of a micrometer by providing a super hard layer consisting of the carbide, nitride, carbonitride, etc., of specific metals to at least the tips of the measuring parts of the spindle an anvil of the micrometer. CONSTITUTION:An object to be measured is interpoosed between the spindle 2 and anvil 3 of the micrometer and the tip part 2a thereof is advanced and retreated by the rotation of the spindle 2, by which the length, etc. of the object to be measured are measured. The super hard layer consisting of carbide, nitride and carbonitride (for example, TiC, TiN, SiC, etc.) groups IVa Va, VIa metals of the periodic table and Si, diamond, hard carbon, etc., is formed on tips 2a, 3a of the spindle 2 and anvil 3 3 by a vacuum deposition method, sputtering method, ion plating method, CVD method, PVD method, etc. The durability and reliability which are excellent for a long period of time are thus maintained without the wear of the measuring ends 2a, 3a.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a micrometer with improved reliability during durability.

(Prior art) Conventionally, the spindle and anvil of a buikrometer have generally been made of tool steel (JIS 5K931, etc.), which has been heat treated to increase the hardness to HRC 55-85. H-ma 1400-1 at the tip
A brazed cemented carbide tip with a hardness of 800 was used.

(Problems to be solved by the invention) However, tools using the above-mentioned tool steel lack wear resistance and corrosion resistance and are prone to early wear, while tools using cemented carbide have poor hardness. Although the wear resistance is improved somewhat by increasing the size, unevenness and wear scars are unavoidable due to locally applied high loads, and as a result, both result in poor flatness and parallelism and are unsatisfactory. There was a problem that durability was difficult to obtain.

In particular, recently, high-grade micrometers that electrically detect and digitally display the amount of spindle movement have come into widespread use, and the lack of durability of the spindle and anvil has affected the reliability of the micrometer. This was a major cause of losses, and a fundamental solution was desired.

The present invention was made to solve the above-mentioned conventional problems, and an object of the present invention is to provide a highly durable and reliable micrometer.

(Means for Solving the Problems) For this reason, the present invention provides at least the measurement surfaces of the spindle and anvil with the elements (a) of the Periodic Table of Elements.

The gist is that at least one type of coating layer selected from ultra-hard substances such as carbides, nitrides, or carbonitrides of Va, IA group metals or Si, diamond, or hard carbon (amorphous) is provided in one or multiple layers. do.

The micrometer to which the present invention is applied is of any type, and may be a general-purpose micrometer, a micrometer for screw measurement, a micrometer for gear measurement, or the like. Furthermore, the base material of the spindle or anvil is not particularly limited, and may be selected from, for example, special steel such as special tool steel, die steel, and high-strength tool steel, or cemented carbide.

The thickness of the coating layer is preferably about 0.5 to 204 m. This is because if the thickness is less than 0.5 μm, it will be difficult to increase the surface hardness due to the influence of the hardness of the base material. On the other hand 2
This is because if the thickness exceeds 0μ layer, the economical efficiency will deteriorate unnecessarily. In addition, especially when the film thickness is about 0.5 to 3 cm, the surface roughness of the base material will appear as it is on the surface of the coating layer, so if the base material is finished (wrapped, etc.) This eliminates the need for finishing after coating, which is extremely advantageous.

In the present invention, the coating layer may be formed only on the measurement surface of the spindle or anvil, or on the entirety thereof.In particular, when the coating layer is formed on the entirety of the anvil, the durability is improved by improving the wear resistance of the threaded part. Further improvements in performance can be achieved.

In order to make the coating layer multi-layered, for example, a substance A having a high affinity with the base material and being stable against peeling of the coating is used as the first coating layer, and a substance B having high wear resistance is formed on the second coating layer. In this case, a further improvement in peel strength and abrasion resistance can be achieved than with a single layer coating of only substance A or only substance B.

Furthermore, various chemical and physical techniques can be employed to form the coating layer, such as CVD, vacuum evaporation, sputtering, ion plating, and the like.

The coating layer provided in this manner has a high hardness of about 000 Hv for iN, about 3200 Hv for TiC, about 2500 Hv for SiC, and about 10000 Hv for diamond.

(Function) In the micrometer configured as described above, since a coating layer made of an ultra-hard material is provided on the spindle and anvil, the hardness of the measurement surface increases, the friction coefficient thereof decreases, and wear resistance is significantly improved. Ru. Along with this, corrosion resistance has also improved, making it difficult for unevenness or wear and tear to occur on the measurement surface.
The durability and reliability of micrometers as a whole will be significantly improved.

(Example) Hereinafter, an example of the present invention will be described based on the accompanying drawings.

The figure shows a digital display micrometer according to the present invention. In the figure, 1 is a U-shaped W frame, a spindle 2 is rotatably provided at one end of the frame 1, and an anvil 3 is fixedly provided at the other end of the frame 1 opposite to the spindle 2. has been done. A simple 5 is integrally fitted to one end of the spindle 2 extending outside the frame 1 via a fitting part 4, and a simple 5 is integrally fitted to the frame 1, extending between the spindle 2 and the simple 5. A sleeve 8 screwed onto the spindle 2 via a threaded portion 7 is fixed via a holding member 9. That is,
The spindle 2 can move forward and backward toward the anvil 3 following the rotational movement of the simple 5.

Here, this micrometer detects the amount of mechanical displacement of the spindle 2 using an encoder, inputs an electric signal pulse corresponding to this detected amount to a counting circuit, and uses the counting circuit to calculate the output of the encoder. A digital display l provided on the side of the frame l counts the electrical signal pulses generated by the frame l.
It is equipped with means for digital display on the O.

The encoder includes a holding cylinder 11 slidably fitted onto the spindle 2, a rotating cylinder 12 fitted and fixed to the holding cylinder 11, and fixed to the frame 1 at a constant distance from the rotating cylinder 12. It has a fixed cylinder 13. Holding tube 1
1 is urged in the axial direction by a spring 14 seated on the frame 1, and its rotation with respect to the spindle 2 is restricted by a pin 1B that engages with a keyway 15 provided in the spindle 2. As a result, the rotating cylinder 12 is connected to the spindle 2.
It is possible to rotate integrally with the spindle 2 while allowing movement in the axial direction. Although not shown, the stationary tube 13 is provided with a transmitting electrode and a receiving electrode, while the rotating tube 12 is provided with a coupling electrode and a ground electrode for electrostatically coupling the two electrodes. As a result, if the rotary tube 12 is rotated while an alternating current voltage consisting of a rectangular wave or a sine wave with different phases is applied to the transmitting electrode, an output signal with a phase corresponding to the amount of rotational displacement of the rotary tube 12 is output from the receiving electrode. can be obtained. That is, by comparing the phase of the signal output from the receiving electrode with a predetermined reference phase,
The amount of displacement of the spindle 2 can be measured.

Therefore, in this embodiment, a coating layer (indicated by diagonal lines) made of an ultra-hard material is provided on each of the tips 2a and 3a of the spindle 2 and anvil 3.

Ultra-hard substances include Na, Va, and vI in the periodic table of elements.
Carbide, nitride or carbonitride of group a metal or Si,
Alternatively, diamond or hard carbon may be selected as appropriate; for example, Tie, TiC, SiC, hard carbon, etc. can be selected. In addition, the coating layer can be formed by 1, for example, CVD.
Various chemical and physical techniques can be employed, such as the method, vacuum evaporation method, sputtering method, and ion blating method.

Furthermore, it is desirable that the thickness of the coating layer be 0.5 to 20 μm.
N is about 2000 H, TiC is about 3200, S
Hma about 2500 with rC, Hma 1000 with diamond
The hardness is as high as 0.

With this configuration, when the simple 5 is rotated, the spindle 2 is advanced, and the object to be measured is held between the spindle 2 and the anvil 3, the amount of displacement of the spindle 2 is detected electrically, and a digital display is displayed. digitally displayed on 10.

By the way, a coating layer made of an ultra-hard material is provided on the tips 2a and 3a of the spindle 2 and anvil 3, and due to its high hardness and low friction coefficient, there is a gap between the spindle 2 and anvil 3. Not only does the measurement surface not wear out prematurely even when the object to be measured is repeatedly held, but the improved corrosion resistance prevents corrosion on the measurement surface, eliminating the early occurrence of corrosion scratches that cause wear. . As a result, especially in a high-grade micrometer equipped with a digital display function, such as the one in this embodiment, durability commensurate with the product price can be guaranteed, and its reliability is extremely high.

Note that in the above embodiment, the N layer was provided only on the tip ends 2a and 3a of the spindle 2 and anvil 3, but instead of this, the coating layer could be provided only on the end surface of the spindle 2 or anvil 3, or on the entire end surface. Of course, this is a good thing. In particular, when provided throughout the entire body, the threaded portion 7 of the spindle 2 will not wear out prematurely, making it possible to achieve further improvement in durability and Φ reliability.

(Effects of the Invention) As explained above in detail, the micrometer according to the present invention is provided with a coating layer made of an ultra-hard material on at least the measurement surfaces of the spindle and anvil, so that the measurement surfaces can be quickly removed. There was no wear, and there was no early occurrence of unevenness or wear scratches on the measurement surface, resulting in the effect of significantly improving durability and reliability.

[Brief explanation of the drawing]

The figure is a sectional view showing an example of the structure of a micrometer according to the present invention. 2... Spindle 3... Anvil

Claims (1)

[Claims] (1) At least on the measurement surface of the spindle and anvil,
It is characterized by being provided with a coating layer of at least one type selected from metals of groups IVa, Va, and VIa of the Periodic Table of the Elements, carbides, nitrides, or carbonitrides of Si, diamond, or hard carbon, in one layer or in multiple layers. micrometer.