JP2020056669A - Measurement device - Google Patents

Abstract

To provide a measurement device which reduces accuracy degradation by reducing inertial force of an indicator needle.SOLUTION: A measurement device provided herein includes a needle-type display unit. An indicator needle thereof is made of resin and formed to have thickness decreasing from a based end thereof toward a tip end such that the tip end is thinner than the based end.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a measuring instrument. Specifically, the present invention relates to a measuring instrument having a pointer-type display unit, for example, a dial gauge.

  Dial gauges are known. The dial gauge mainly compares and measures a master or a block gauge with a measurement object (work), and inspects whether or not there is a processing error and whether or not the error is within a tolerance. The comparative measurement by the dial gauge plays a very important role in the inspection of the dimensional accuracy of the product.

  The dial gauge displays the displacement of the tracing stylus as the amount of rotation of the pointer. The linear movement amount of the tracing stylus is converted into a rotational movement, expanded by a built-in gear train, and transmitted to the hands. Then, the pointer rotates.

  When using the dial gauge, install the dial gauge on a stand or the like. The user lifts the tracing stylus upward by hand, and sets the master or work directly below the tracing stylus. Then, when the user releases his / her hand from the stylus, the stylus lowers due to its own weight and the biasing force of the built-in spring, and the stylus comes into contact with the master or the work. Read the scale (measured value) on the scale plate indicated by the pointer when the stylus comes into contact with the master or the work.

  When using the dial gauge, the user raises and lowers the stylus by hand, and the stylus lowers suddenly due to its own weight and the urging force of the spring. At this time, the pointer suddenly starts rotating at high speed and stops suddenly. In the movement of sudden rotation or sudden stop, a considerable force acts on the pointer vertically and horizontally. Thus, the dial gauge pointer is made of a metal-based material (metal material) such as an iron alloy or a copper alloy so as to withstand such a force.

Patent 3675587 Patent 4399186

If the pointer is formed of a metal material, the pointer can withstand a certain amount of force. However, guidelines made of metallic materials have some weight. Then, when the stylus stops suddenly, a large inertial force is generated on the metal pointer, which acts on the gear train and deforms the tooth surfaces of the rack, pinion, and gear train, leading to deterioration in accuracy and damage. There was fear.
Some metal hands have a balancer in order to eliminate the difference in measuring force during one rotation of the hand. That is, the pointer having the balancer has the balancer for balancing the pointer portion pointing to the scale on the opposite side across the rotation axis. The metal pointer having such a balancer has an increased inertia force due to the increase in weight, and the load applied to the gear train has been considerably large.

  Therefore, an object of the present invention is to provide a measuring instrument in which the inertial force of the pointer is reduced and the deterioration in accuracy is reduced.

The measuring instrument of the present invention
A measuring instrument having a stylus that comes into contact with a measurement target, and having a pointer-type display unit that converts a displacement of the stylus into a rotation amount of a pointer by enlarging the displacement by an enlargement mechanism and displays the rotation.
The pointer is formed of a resin.

In one embodiment of the present invention,
It is preferable that the pointer has a thickness on the proximal end side larger than that on the distal end side.

In one embodiment of the present invention,
The pointer is a surface far from the scale plate, the front surface is a surface perpendicular to the rotation axis,
It is preferable that the back surface, which is the surface close to the scale plate, is a surface that is inclined so as to move away from the scale plate from the base end toward the distal end.

In one embodiment of the present invention,
The pointer is a surface close to the scale plate, the back surface is a surface perpendicular to the rotation axis,
It is preferable that the front surface, which is a surface farther from the scale plate, be inclined so as to approach the scale plate from the base end toward the distal end.

In one embodiment of the present invention,
Furthermore, it has a metal pointer holder having a cylindrical part for fitting the pointer shaft,
It is preferable that the pointer is formed with the pointer holder inserted.

In one embodiment of the present invention,
It is preferable that the cylindrical portion has a flat surface or irregularities on its outer periphery.

In one embodiment of the present invention,
It is preferable that the pointer is integrally formed in a shape having a cylindrical portion into which the pointer shaft is fitted.

In one embodiment of the present invention,
Preferably, the pointer shaft has a knurl.

In one embodiment of the present invention,
The measuring instrument is preferably a lever type dial gauge or a dial gauge.

It is a front view of the dial gauge 10 (measuring device). FIG. 3 is an exploded view of the dial gauge 10 (measuring device). FIG. 2 is a plan view (A) and a side view (B) of the resin pointer 100. FIG. 2 is a plan view (A) and a side view (B) of the resin pointer 100. FIG. 3 is a diagram illustrating a pointer holder 200. FIG. 3 is a diagram illustrating a pointer holder 200. It is a figure which illustrates the pointer integrally formed including the cylindrical part. It is sectional drawing in the state where the pointer | guide was attached to the pinion shaft of the last stage. FIG. 2 is a diagram illustrating an example of a pointer provided with a balancer; FIG. 2 is a plan view (A) and a side view (B) of the resin pointer 100.

Embodiments of the present invention are illustrated and described with reference to the reference numerals assigned to each element in the drawings.
(1st Embodiment)
FIG. 1 is a front view of the dial gauge 10 (measuring device).
FIG. 2 is an exploded view of the dial gauge 10 (measuring device).
The dial gauge 10 displays the displacement of the tracing stylus 51 as the amount of rotation of the pointer 100.

The dial gauge 10 includes a main body case 40, a spindle 50, an enlargement mechanism 30, and a main body cover 20.
The main body case 40 is a short cylindrical case body whose one end face is open. A stem 60 and an upper bush (70) protrude from a side surface of the main body case 40, and the spindle 50 is supported by the stem 60 and the upper bush (70).

  The spindle 50 has a tracing stylus 51 at the distal end, and the base end is housed in the main body case 40. The spindle 50 is supported by a stem 60 and an upper bush (70), and is supported so as to be able to advance and retreat in the axial direction.

The magnifying mechanism 30 is a combination of a plurality of gears that magnify the linear displacement of the tracing stylus 51 and converts it into the amount of rotation of the pointer 100, and is housed inside the main body case 40.
Here, the linear displacement of the spindle 50 is converted into the rotation of the pinion by a pinion (not shown) meshing with a rack (not shown) provided on the spindle 50, and the rotation of the pinion is expanded by a plurality of gear trains. To go.

The main body cover 20 has an outer frame portion 21 and a cover plate 22.
The outer frame portion 21 is a short cylinder having both ends opened, and is attached to an opening end face of the main body case 40 via an O-ring 41, for example. A scale plate 42 is attached to the outer frame 21. Further, a pointer 100 is arranged on the scale plate 42, and the pointer 100 is connected to the pinion 32 which is the final stage of the enlargement mechanism 30.

  Here, the pointer 100 and the scale plate 42 constitute a pointer type display unit.

  The outer frame 21 is rotatable with respect to the main body case 40. When the outer frame 21 is rotated, the scale plate 42 is rotated together with the outer frame 21.

  The cover plate 22 is a transparent disk-shaped thin plate. It may be glass or may be formed of a transparent resin such as acrylic. The cover plate 22 is fixed to the end surface of the outer frame 21 so as to close the opening of the outer frame 21.

The pointer 100 is formed of a resin.
FIG. 3 is a plan view (A) and a side view (B) of the resin pointer 100.
In the plan view (A), the resin pointer 100 is wide at the base end and gradually narrows toward the front end. In addition, in the side view (B), the base end is thick and gradually becomes thinner toward the tip.

A conventional metal pointer also has a shape that tapers from a base end to a front end in a plan view.
However, regarding the thickness, the conventional metal pointer is manufactured by punching a thin metal plate, so that the thickness in the side view is the same on the base end side and the tip end side. With a metal pointer, rigidity can be maintained even with a thin plate due to the characteristics of the metal material. Therefore, in order to reduce the weight, the base end side and the distal end side are thinned with the same thickness.
On the other hand, in the resin pointer 100, rigidity cannot be maintained if the whole is made thin. Therefore, the base end is made thick to maintain rigidity.
However, if the tip is also made thick, a large inertial force is generated when the pointer 100 rotates rapidly (high-speed rotation) and stops suddenly, so the tip side is made thin.

Now, as the length of the pointer, the length from the rotation axis to the distal end of the pointer is L, the thickness at the proximal end is Hr, and the thickness at the distal end is He. Further, the thickness at the middle point is represented by Hh.
Hr / L is preferably in the range of 0.03-0.09 if the thickness can be slightly reduced, and should be in the range of 0.03-0.15 if the thickness should be slightly increased. Is preferred.
Hh / L is preferably in the range of 0.02 to 0.05.
He / L is preferably in the range of 0.005 to 0.01.

In addition, the width at the tip is We, and the width at the midpoint is Wh.
At this time, if the width is large, the rigidity can be maintained even if the width is small.
Hh ≦ {Hr / (L / 2 + Wh)}
He ≦ {Hr / (L + We)}

Here, when the thickness of the pointer 100 is reduced from the base end to the tip end, in FIG. 3, the front surface (the surface far from the scale plate) is flat, and the back surface is directed from the base end to the tip end. As a result, the surface is inclined away from the scale plate 42.
In other words, considering the rotation axis Ax of the pointer 100 as a reference, the front surface of the pointer 100 is a plane perpendicular to the rotation axis Ax, and the back surface is a surface inclined with respect to the rotation axis Ax. I have. The tip of the pointer 100 swings up and down when the pointer 100 rotates rapidly (high-speed rotation) or stops suddenly. This is to prevent the tip of the pointer 100 from touching the scale plate 42 even in such a case.

  In addition, for example, the back surface of the pointer 100 may be a curved surface (projecting upward) as illustrated in FIG.

In attaching the pointer 100 to the shaft of the pinion 32 at the final stage, a pointer holder 200 illustrated in FIG. 5 is used. (The axis of the final stage pinion 32 is a pointer axis.) The pointer holder 200 has a disk-shaped head plate portion 210 and a cylindrical portion 220 protruding from the back surface of the head plate portion 210. ing.
Here, the pointer holder 200 is made of metal. By pressing the shaft (pointer shaft) of the pinion 32 into the cylindrical hole of the cylindrical portion 220, the pointer holder 200 is attached and fixed to the shaft (pointer shaft) of the pinion 32.

  Here, in this embodiment, since the hands 100 are made of resin, the hands 100 made of resin can be injection-molded (insert-molded) with the hand holder 200 inserted. Thus, the number of steps for attaching the pointer holder 200 and the pointer 100 in a later step can be reduced. (In the case of the conventional metal pointer, the pointer and the pointer holder were connected by press fitting and caulking.)

At this time, in order to prevent slippage from occurring between the pointer holder 200 and the resinous pointer 100, it is preferable to provide unevenness or a flat surface on the pointer holder 200 to prevent slipping. In FIG. 5, a part of the base of the cylindrical portion 220 is a flat surface 221. That is, the entire circumference of the cylindrical part 220 is not circular, but the plane part 221 is provided.
Here, the two flat surfaces 221 are provided so as to face each other with the central axis therebetween, but may be one surface or a more polygonal shape. FIG. 6 shows an example in which irregularities (knurls) 222 are provided at the base of the cylindrical portion 220.

In the examples of FIGS. 5 and 6, the metal pointer holder 200 is insert-molded into the resin pointer 100, but the pointer 100 including the cylindrical part corresponding to the cylindrical part 220 of the pointer holder 200 is integrally formed of resin. Is also good. That is, as illustrated in FIG. 7, the entire pointer 100 is formed of resin, and a cylindrical portion 220 that receives the shaft (pointer shaft) of the pinion 32 is provided at the base end.
The shaft of the pinion 32 (pointer shaft) is inserted into the cylindrical portion 220, and the pointer 100 is attached to the shaft of the pinion 32 (pointer shaft). However, sliding is performed between the cylindrical portion 220 and the shaft of the pinion 32 (pointer shaft). In order to prevent the occurrence of the rotation, it is preferable that the shaft (pointer shaft) of the pinion 32 is provided with unevenness (knurl) 33 for stopping rotation.
FIG. 8 is a cross-sectional view showing a state where the pointer 100 is attached to a shaft (pointer shaft) of the pinion 32.

In the present embodiment, since the hands 100 are made of resin, even when the hands 100 are rapidly rotated (high-speed rotation) or stopped suddenly, the inertia force generated in the hands 100 is reduced, and as a result, the force applied to the gear train Becomes smaller. This prevents the rack, the pinion, and the gear train from deteriorating or being damaged, and maintains the measurement accuracy of the dial gauge (measuring device) 10.
In addition, the shape of the resin pointer 100 is made sufficiently thick at the base end and thinner toward the distal end, so that the rigidity of the pointer 100 is sufficiently maintained and the weight of the pointer 100 is reduced. be able to.

  It should be noted that the present invention is not limited to the above-described embodiment, and configurations that are appropriately changed without departing from the spirit of the present invention belong to the technical scope of the present invention.

In the above embodiment, when the pointer 100 is made thinner from the base end to the tip end, the front surface (the surface farther from the scale plate) is flat, and as the back surface goes from the base end to the tip end. The surface was inclined away from the scale plate 42 (FIG. 3).
On the contrary, as shown in FIG. 10, for example, the front surface (the surface far from the scale plate) is an inclined surface, and the back surface is a flat surface (a surface parallel to the scale plate). Is also good. The closer the distance between the scale plate 42 and the tip of the pointer 100 is, the easier it is to read the scale indicated by the pointer 100.

  In the above embodiment, the dial gauge 10 is exemplified, but the present invention is also effective for a lever type dial gauge, a needle display type caliper or a micrometer. That is, the present invention is effective as long as it is a small measuring instrument of a pointer display type.

  As illustrated in FIG. 9, the pointer 100 may be provided with a balancer 120. In other words, the pointer 100 is provided with a balancer 120 for balancing the pointer 110 on the opposite side to the pointer 110 indicating the scale. Of course, the pointer 100 including the balancer 120 is formed of resin. Since the hands 100 are made of resin, the hands 110 can be colored (for example, black or red) and the balancer 120 can be transparent.

DESCRIPTION OF SYMBOLS 10 Dial gauge 20 Main body cover 21 Outer frame part 22 Covering plate 30 Enlargement mechanism 32 Final stage pinion 40 Main case 41 O-ring 42 Scale plate 50 Spindle 51 Measuring element 60 Stem 100 Pointer 110 Pointer part 120 Balancer 200 Pointer holder 210 Head plate Part 220 cylindrical part 221 flat part

Claims (9)

A measuring instrument having a stylus that comes into contact with a measurement target, and having a pointer-type display unit that converts a displacement of the stylus into a rotation amount of a pointer by enlarging the displacement by an enlargement mechanism and displays the rotation.
The said indicator is formed with resin, The measuring device characterized by the above-mentioned. The measuring device according to claim 1,
The pointer is characterized in that the thickness at the proximal end is greater than the thickness at the distal end. The measuring device according to claim 2,
The pointer is a surface far from the scale plate, the front surface is a surface perpendicular to the rotation axis,
A measuring instrument characterized in that the back surface, which is the surface closer to the scale plate, is inclined so as to move away from the scale plate from the base end toward the distal end. The measuring device according to claim 2,
The pointer is a surface close to the scale plate, the back surface is a surface perpendicular to the rotation axis,
A measuring instrument characterized in that the front surface, which is the surface farther from the scale plate, is inclined so as to approach the scale plate from the base end toward the distal end. The measuring device according to any one of claims 1 to 4,
Furthermore, it has a metal pointer holder having a cylindrical part for fitting the pointer shaft,
The measuring instrument, wherein the pointer is formed with the pointer holder inserted. The measuring device according to claim 5,
The measuring device, wherein the cylindrical portion has a flat surface or unevenness on an outer periphery thereof. The measuring device according to any one of claims 1 to 4,
The measuring instrument, wherein the pointer is integrally formed in a shape having a cylindrical portion into which the pointer shaft is fitted. The measuring device according to claim 7,
The said pointer axis | shaft has a knurl. The measuring device characterized by the above-mentioned. The measuring instrument according to any one of claims 1 to 8,
The measuring instrument is a lever type dial gauge or a dial gauge.