JPH0511564B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for accurately measuring the diameter of extremely small pores.

When measuring the inner diameter with a displacement electric transducer such as an electric micrometer, it is common to insert two probes into the hole to be measured and expand them in the diametrical direction. In this case, the probe becomes very thin, which has disadvantages such as deformation, causing deflection errors due to pressure measurement, etc., and damage during insertion, and there is a limit to the minimum hole diameter that can be measured. In addition, when using an air micrometer, measurements are taken by inserting an air jet that blows in the diametrical direction into a small hole to be measured, but it is difficult to manage the loss of accuracy due to jet wear and to handle it to prevent damage. In addition, since the air jet requires machining and forming an axial ventilation hole and a diametrical jet nozzle in a small diameter member, the smaller the diameter, the more difficult the machining and manufacturing become. For this reason, conventionally, the minimum measurable pore diameter is
It has been said that the electric type with two probes can be used up to about φ2mm, and the pneumatic type with an air jet can be used up to about φ1mm.

The present invention was invented and developed in order to improve these conventional techniques, and enables electrical measurement using a single probe with an extremely small inner diameter, and can be applied to smaller diameters compared to conventional devices. To provide an extremely small inner diameter measuring instrument that is accurate, causes little damage to the probe, and is relatively easy to operate.

First, an overview of the configuration of the present invention will be explained with reference to FIG. 2 shown in the right part of the figure is one probe lever having a fulcrum 1. A contact 3 is provided at the right end of this probe lever 2, and this is inserted into the hole 4 to be measured. Contact 3 around fulcrum 1
In the figure, the detector 5 is swung vertically along the plane of the paper so that it comes into contact with the diameter position of the hole 4, and the output of the detector 5 at this time is detected. Then, the maximum value and minimum value of the detection signal are determined, the difference between them, that is, the amplitude is calculated, this is compared with the master amplitude that has been measured and stored in advance, and the difference is output as a measured value.

An example of a swing drive mechanism for swinging the probe lever 2 up and down is shown in the left part of FIG. An eccentric cam 7 is attached to the motor 6, and the eccentric cam 7 is connected to the left end of the upper lever 8 (swinging lever) supported by a fulcrum 9 and the lower lever 10 (swinging lever) supported by a fulcrum 11. Its outer periphery is opposite to the left end of the figure. Moreover, between the right end of the upper lever 8 and the right end of the lower lever 10,
The left end of the probe lever 2 is located via upper and lower balancing springs 12 and 13.

With this configuration, when the motor 6 is rotated, the eccentric cam 7 rotates, and the upper and lower levers 8 and 10 are tilted by the lift thereof.
The probe lever 2 swings about the fulcrum 1 in the vertical direction along the plane of the paper in the figure, and the contactor 3 comes into contact with the diameter position of the hole 4 to be measured as described above, and the maximum and minimum is detected as the displacement of

FIG. 2 shows an embodiment of the configuration of the present invention described above. In the figures, parts having the same features as shown in FIG. 1 are designated with the same reference numerals. In this embodiment, the probe lever 2 has an arcuate shape and is supported on a fixed part by a frictionless leaf spring fulcrum 1. A core that can move forward and backward is attached to a coil bobbin fixed to the
A differential transformer 5 is formed. The probe having the contactor 3 can be replaced and used by being attached to the probe lever 2 when it is worn out, damaged, or when the object to be measured is changed. Upper/lower levers 8, 10
The center portion is attached to one end of a rigid body in which thin elastic fulcrums 9 and 10 are formed. The right end of the upper and lower levers 8 and 10 is connected to the probe lever 2 via the balancing coil springs 12 and 13.
The rear ends of the levers 8 and 10 are held in place, and the other ends of the levers 8 and 10 are in contact with the outer periphery of an eccentric cam 7 attached to the shaft of the motor 6 via contact pieces 15 and 16. Further, these main components are housed compactly within the cylindrical casing 17.

In the above configuration, when the contact 3 is inserted into the hole to be measured and the motor 6 is started, the rotation is as follows: rotation of the eccentric cam 7 → vertical movement of the pieces 15 and 16 → upward movement about the fulcrums 9 and 10 , rotation of the lower levers 8 and 10, → rotation of the probe lever around the fulcrum 1, and the contact 3 contacts the upper and lower diameter positions of the inner diameter 4 to be measured, and the The position is detected by the detector 5 as explained with reference to FIG.

FIG. 3 is a block diagram showing the processing of the detector output. As shown in the figure, the detector output when the contactor is applied to the inner peripheral surface to be measured, for example, the lower part in Figure 2, is stored as the minimum value, and the detector output when it is applied to the upper part is stored as the maximum value. Then, both detected values are calculated and the difference between them is output as an amplitude. On the other hand, by detecting, calculating, and storing the minimum value, maximum value, and amplitude of the master in advance using the same procedure as above, and calculating them with the amplitude value of the inner circumference to be measured, the measured value of the inner diameter to be measured can be set to the master inner diameter. It is calculated as the deviation from

Further, the detector is not limited to a differential transformer, and other detectors such as a capacitance type detector can be used in the same manner.

As detailed above, according to the present invention, unlike the conventional technology in which two probes are inserted into the inner diameter of the object to be measured, only one probe is inserted. It can be applied up to an inner diameter of about 0.7 mm, for example, and if the inner diameter to be measured is the same, damage and deflection can be prevented by making the probe thicker and stronger.

In addition, compared to the conventional method using a single probe using an air micrometer, it does not require machining of vertical and horizontal ventilation holes inside the probe, so it is possible to measure smaller hole diameters using a smaller diameter probe. becomes possible,
Excellent effects can be obtained, such as eliminating the need to manage dimensions, lifespan, etc. to deal with deterioration of accuracy due to probe wear.

Further, according to the present invention, the swing lever is swung by the rotation of the eccentric cam, and the amount of swing of the swiveling lever is transmitted to the probe lever via the elastic member, so that the probe lever is connected to the hole to be measured. It is possible to prevent the probe lever from being damaged when it comes into contact with it.

Furthermore, according to the present invention, since the rotating element of the eccentric cam is transmitted to the probe lever via the swing lever, the degree of freedom in design is improved and the miniaturized inner diameter measuring instrument can be easily made compact. can.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the outline of the configuration of the present invention, and FIG.
The figure is a sectional view of one embodiment of the present invention, and FIG. 3 is a block diagram showing the processing output of a detection signal in the embodiment of the present invention. 1... Fulcrum, 2... Probe lever, 3... Contact, 5... Detector, 6... Motor, 7... Eccentric cam, 8, 10... Upper and lower levers, 9, 11... Fulcrum , 12, 13... Balance spring.

Claims (1)

[Scope of Claims] 1. A probe lever having a contact at its tip and swingably supported via a fulcrum, and a probe lever located on the opposite side of the contact of the probe lever across the fulcrum. a detector that detects each position of the swinging contact and outputs a detection signal; and a swing lever that is connected to the probe lever via an elastic member and is swinged by rotation of an eccentric cam of the swing lever. a swinging drive mechanism that swings the probe lever to move the contactor in the diametrical direction and contacts two points at opposing positions in the diametrical direction of the hole to be measured; 1. An extremely small inner diameter measuring device, characterized in that the inner diameter of the hole to be measured is measured based on the difference between a maximum detection value and a minimum detection value output when a child touches two points on the diameter of the hole to be measured.