JPH043213Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field This invention is a measuring instrument for measuring the surface roughness of a mechanical surface, and is particularly suitable for measuring the surface roughness of a machine to be measured. This invention relates to the structure of a measuring electrode in a capacitance type surface roughness measuring device that measures surface roughness by providing an insulating layer and electrically detecting changes in capacitance due to an insulating void formed between the layers. .

(b) Conventional technology Traditionally, methods such as the stylus method, light reflection method, optical interference method, or frictional resistance method have been used to measure the surface roughness of machine surfaces, but all of these methods require complicated equipment. , and has disadvantages or problems, such as requiring time for measurement and often having a limited measurement range. On the other hand, for these surface roughness measurement methods, a measurement electrode is formed between the electrode surface and the surface to be measured via an insulating film of a certain thickness, and the measurement electrode is applied to the surface to be measured with a certain force. A capacitance type surface roughness measuring device is used that measures the surface roughness of the machine surface by pressing the device against the surface of the measuring device and detecting the change in capacitance between the electrode surface of the measuring device and the measurement surface of the object as an electrical signal. ing. This capacitive surface roughness measuring instrument is
Although this method is based on the most advantageous measurement method in principle, it has a drawback in the structure of its measurement electrode.

(c) Problems to be solved by the invention The measurement electrode in the conventional capacitance type surface roughness measuring device described above has a structure in which an insulating sheet is bonded to the surface of a metal plate with an adhesive. Therefore, if the measurement surface of the object to be measured is a mirror surface or a uniform surface such as a lapped surface (RS) as shown in FIG. 3A, the size of the surface irregularities is constant; There were no particular problems with the conventional measurement electrodes as described above. However, as shown in FIG. 3B, for example, when measuring the surface roughness of an irregularly uneven surface that has protrusions caused by hangnails, such as a blasted surface (BS), The insulating film of the measurement electrode is torn by the sharp edge of the electrode, and the electrode and the object to be measured come into contact, resulting in an electrical short circuit, making it impossible to measure capacitance. Therefore, this invention has the above-mentioned drawbacks and is suitable for objects to be measured such as blast-finished surfaces.
In other words, we provide a new measuring electrode for a capacitive surface roughness measuring instrument that prevents electrical short circuits caused by damage to the insulating film on the measuring electrode and enables reliable detection of changes in capacitance. It's about doing.

(d) Means for solving the problem In order to achieve the above-mentioned purpose, this invention specifically uses a measuring electrode provided with an insulating layer on the surface of the electrode surface. is pressed against the surface to be measured of the object to be measured with a constant pressure, and the change in capacitance in the gap formed between the electrode surface of the measurement electrode and the surface to be measured is detected as an electrical signal, and the object to be measured is detected. In a capacitive surface roughness measuring device for measuring surface roughness, the measuring electrode has an electrode base having a connector to the roughness measuring device on one end side and an electrical connection on the other end side. and an electrode forming member attached to the electrical connection portion side of the electrode base through a non-conductive elastic member, and the electrode forming member is attached to one side of the synthetic resin film. It consists of a sheet-like strip having a suitable width with a metal film deposited on its surface, and consists of a measurement surface portion at the center in the length direction of the strip, elastic leg portions extending continuously on both sides of the measurement surface portion, and the elastic leg portions. The electrode forming member is integrally equipped with a mounting portion extending continuously on both sides, and the electrode forming member is
The surface of the synthetic resin film faces outward so as to be in contact with the object to be measured, and the non-conductive elastic member is interposed, and the synthetic resin film is attached to the electrical connection part of the electrode base via the attachment part. This is the structure of a measurement electrode in a capacitive surface roughness measuring device.

(E) Description of Embodiments Hereinafter, the measurement electrodes in the capacitive surface roughness measuring device according to the present invention will be described in detail based on specific embodiments shown in the drawings.

The measuring electrode 1 in this invention basically includes an electrode base 2, an electrode forming member 3, and a non-conductive elastic member 4 interposed therebetween. The electrode base 2 is provided with a connector 5 to a roughness measuring device on one end side, and an electrical connection portion 6 to the electrode forming member 3 on the other end side. On the other hand, the electrode forming member 3 is formed on one side 8 of the synthetic resin film 7.
It is made of a sheet member on which a thin layer of metal film 9 is formed. The synthetic resin film 7 is formed of, for example, a polyester film having a thickness of about 40 to 60 microns. The synthetic resin film 7
If it is thinner than this, it will cause elastic deformation during measurement, making it unsuitable for accurate capacitance measurement, and if it is thicker than this, the change in capacitance due to surface roughness will be small ( deterioration of the S/N ratio), making it unsuitable as a measuring electrode in a capacitive surface roughness measuring device. On the other hand, the metal film 9 formed on one side 8 of the synthetic resin film material 7 is most preferably an aluminum vapor-deposited film having a thickness of about 3 to 5 microns, for example. If the metal film 9 is thinner than this, the electrical resistance will increase and its function as a conductor will be impaired; if it is thicker than this, the elasticity of the insulating film will be impaired, and if the insulating film is torn, the metal film will remains unbroken, causing an electrical short between the electrode and the surface to be measured. The electrode forming member 3 is formed by punching a sheet member formed by vapor-depositing a metal film 9 on one side 8 of a synthetic resin film 7 into the shape shown in FIG. 2, for example. The electrode forming member 3 has attachment parts 10 and 1 to the electrode base 2.
0, and elastic leg portions 11, 11 that curve in the opposite direction.
and a measuring surface portion 13 which substantially limits the area of the measuring surface by the cutouts 12,12. Mounting portion 10 and measurement surface portion 1 of the electrode forming member 3
3 are formed parallel to each other during assembly, and a non-conductive elastic body 4 is placed between them.
is formed so that there is an intervening The elastic body 4
is made of a non-conductive elastic material such as rubber or porous elastic material. The elastic body 4 is made of a material having greater elasticity than the electrode forming member.

(f) Effects of the invention In the measuring electrode of the capacitance type surface roughness measuring device of this invention, which has the above configuration, the electrode forming member that comes into direct contact with the measurement surface of the object to be measured is in contact with the synthetic resin film. It is made up of a sheet-like sheet with a metal film deposited on one side and a strip-like material having an appropriate width, and is thin and highly flexible, and this electrode forming member has an elastic member 4 interposed therebetween. In addition to the fact that the electrode forming member is attached to the electrode base body in a state in which (see A), the insulating film in the electrode forming member is less likely to be damaged. Furthermore, even if the insulating film is broken by the protrusion (see Figure 4B), the metal vapor deposited film will also be broken, so the protrusion of the object to be measured and the electrode will not come into contact with each other. No electrical short circuit occurs. Furthermore, the measuring electrode of this invention has a structure in which an insulating film and a vapor-deposited metal are used, unlike the conventional measuring electrode (see Fig. 5), which has a structure in which an insulating sheet S is bonded to a metal plate M using an adhesive B. Since the bonding is uniform and no adhesive or the like is involved, moisture and dust do not enter between the insulating film and the deposited metal film. Therefore, since the dielectric constant of that part does not change, there is no change in the specific capacitance of the electrode itself, and it can be said to be extremely effective as a measuring electrode for a capacitive surface roughness measuring device.

[Brief explanation of drawings]

FIG. 1 is a side sectional view showing an example of a measuring electrode in the capacitance type surface roughness measuring device of this invention, and FIG. 2 is a plan view showing an expanded state of the electrode forming member.
3A and 3B are enlarged side sectional views showing the state of the measurement surface; FIG. FIG. 4B is a side sectional view showing damage to the electrode surface of the measurement electrode, and FIG. 5 is a side sectional view showing damage to the insulating film of the conventional measurement electrode. DESCRIPTION OF SYMBOLS 1...Measurement electrode, 2...Electrode base, 3...Electrode forming member, 4...Elastic member, 7...Synthetic resin film, 9...Metal film, BS...Blast finished surface.

Claims (1)

[Claims for Utility Model Registration] A measuring electrode with an insulating layer on the surface of the electrode,
The electrode surface of the measurement electrode is pressed against the surface to be measured of the object to be measured with a constant pressure, and the change in capacitance in the gap formed between the electrode surface of the measurement electrode and the surface to be measured is converted into an electrical signal. In a capacitance type surface roughness measuring device that detects and measures the surface roughness of the object to be measured, the measuring electrode is provided with a connector 5 to the roughness measuring device on one end side, and an electrical connection on the other end side. It is a combination of an electrode base 2 having a connecting part 6 and an electrode forming member 3 attached to the electrical connecting part 6 side of the electrode base 2 via a non-conductive elastic member 4, The forming member 3 is made of a sheet-like strip of a synthetic resin film 7 with a metal film 9 vapor-deposited on one side 8 and has an appropriate width. 13. Elastic leg portions 1 that extend continuously on both sides.
1, 11, and mounting portions 10, 10 extending continuously on both sides of the elastic leg portions 11, 11, the electrode forming member 3 is formed such that the surface side of the synthetic resin film 7 thereof is It is attached to the electrical connection part 6 of the electrode base 2 via the attachment parts 10, 10 with the non-conductive elastic member 4 interposed so as to face outward so as to form a contact surface with the object to be measured. The structure of the measuring electrode in the capacitive surface roughness measuring device.