JP2546427Y2 - Magnetic attraction force measuring device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring a magnetic attraction force of an electromagnet or the like.

[0002]

2. Description of the Related Art Conventionally, when measuring the magnetic attraction force on a working surface (electromagnet) of an electromagnetic chuck used for a surface grinding machine, for example, as shown in FIG. Then, the hook 4 of the commercially available spring balance 3 is engaged with the probe 2, and the spring balance 3 is pulled up.
The measuring element 2 comes off the work surface 1 at the moment when the load from the spring balance 3 overcomes the suction force of the work surface. At the moment when the load comes off, the maximum tensile load is measured from the scale 6 indicated by the pointer 5. Read visually and repeat this measurement several times,
The arithmetic average of the measured values is defined as the magnetic attraction force of the work surface 1.

[0003]

In the conventional measuring means using the spring balance 3, it is difficult to accurately pull the center of the tracing stylus 2 in the vertical direction with respect to the work surface 1, and it is liable to be suspended obliquely. , It is difficult to obtain accurate measurements.

In the spring balance 3, the measuring element 2 is
It is difficult to accurately read the scale 6 at the moment when the scale deviates from the point of view, and there is no other way but to rely on the memory, so that anxiety always remains, requiring skill.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described circumstances, and has as its object to provide a magnetic attraction force measuring apparatus in which even a beginner can easily obtain an accurate measured value of the magnetic attraction force.

[0006]

According to a first aspect of the present invention, there is provided a measuring instrument supporting structure mounted on a surface to be measured with a magnetic attraction force, and an object for measuring the magnetic attraction force on an upper portion of the measuring instrument supporting structure. Measuring instrument that measures the tensile load and displays the maximum load value with a measuring axis that is movably provided in the direction perpendicular to the surface and protrudes vertically toward the surface to be measured for magnetic attraction force, and a measuring axis of this measuring instrument A probe that is concentrically connected to the tip of the probe via a connecting member and that is magnetically attracted to the surface to be measured for magnetic attraction force, and that the probe that is provided at the lower portion of the measuring instrument support structure is movable while being concentric with the measurement axis. And a non-magnetic guide for guiding the magnetic force.

According to a second aspect of the present invention, both ends of the connecting member according to the first aspect are interposed via balls fixed to the both ends,
The magnetic attraction force measuring device is engaged with the center hole of the measuring shaft and the center hole of the measuring element.

[0008]

According to the first aspect of the present invention, the measuring device provided on the upper part of the measuring device supporting structure and the measuring element guided by the non-magnetic guide at the lower portion are kept concentric, and these are magnetic. It is kept on a vertical line with respect to the surface to be measured.
Then, when an upward force is applied to the measuring device, a tensile load is concentrically applied to the measuring axis of the measuring device from the tracing stylus attracted to the magnetic attraction force measurement target surface via the connecting member. The maximum load applied to the measurement axis when the probe comes away from the surface to be measured is measured by a measuring instrument and displayed.

According to a second aspect of the present invention, the balls at both ends of the connecting member are concentrically engaged with the center hole of the measuring shaft and the center hole of the measuring element, and the measuring shaft, the connecting member and the measuring element are automatically aligned. Aligned.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the embodiments shown in FIGS. This example is used for a performance test of an electromagnetic chuck used for a surface grinder.

As shown in FIG. 1, a stand 12 as a measuring instrument support structure is placed on an electromagnetic chuck working surface 11 as a magnetic attraction force measuring surface. This stand 12
It comprises a lower base plate 13, a column 14 erected on the base plate 13, and a measuring instrument guide 15 fitted to the column 14 so as to be able to move up and down.
The measuring device guide 15 is fixed to the column 14 by a tightening screw 16.

A measuring instrument 21 is attached to the measuring instrument guide 15 on the upper portion of the stand so as to be movable in a direction perpendicular to the work surface 11, and is guided by a handle 22 attached to the guide side surface.
The measuring device 21 is moved up and down via an internal mechanism such as a pinion rack provided in the device 15. When no force is applied to the handle 22, the measuring device 21 is pushed up by a compression coil spring 24 provided between the upper surface of the measuring device guide 15 and a locking plate 23 projecting behind the measuring device 21. At the same time, the elevation of the locking plate 23 is locked at a fixed position by a stopper 25 projecting from the upper surface of the guide.

The measuring device 21 measures the tensile load applied to a measuring shaft 26 projecting vertically downward and digitally displays the tensile load. The principle is that the tensile load applied to the measuring shaft 26 is measured by a strain gauge, a piezoelectric It has a digital display function with a peak hold that converts it into an electric quantity by an element or the like, holds the maximum load value by an electronic circuit, and displays it on the liquid crystal display unit 27. For example, full-scale measuring instruments
Known are those with 50 kg, a minimum scale of 0.1 kg, and a display error of 0.3% FS.

A measuring element (iron block) 32 which is magnetically attracted to the electromagnetic chuck working surface 11 is connected to a tip of a measuring shaft 26 of the measuring device 21 via a connecting wire 31 as a connecting material. .

A frame-shaped non-magnetic guide 33 is fitted and attached to the base plate 13 under the stand. Inside the non-magnetic guide 33, the tracing stylus 32 is concentric with the measuring shaft 26 on the work surface. It is guided to move vertically with respect to 11.

As shown in FIG. 2, the non-magnetic guide
33, a flange portion 42 fixed to the upper surface of the base plate by screws 41 is integrally formed on the upper portion of the cylindrical portion 40 fitted to the end face notch portion 13a of the base plate 13, and a pair of convex ridges is formed on the end surface of the cylindrical portion 40. A portion 43 is formed integrally, and a probe fitting recess 44 is provided between the pair of ridges 43. The side surfaces of the pair of ridges 43 are closed by a non-magnetic plate 46 fixed by screws 45, and the tracing stylus 32 is fitted in a square frame having only the upper and lower surfaces open so as to be vertically movable. Is done. The non-magnetic guide 33 and the non-magnetic plate 46 are formed of, for example, acrylic resin.

As shown in FIG.
Are inserted into a small-diameter central hole 52 of an attachment 51 and a small-diameter central hole 53 of a tracing stylus 32, respectively, which are screwed to the measuring shaft 26, and are further drilled into the diameter portions of upper and lower balls (steel balls) 54. The caulking 55 is provided so as to be inserted into each of the holes and not to come out of the small holes.

In this way, the balls 54 fixed to the upper and lower ends of the connecting wire 31 are provided with a large-diameter center hole 56 screwed to the measuring shaft 26 and a large-diameter center hole drilled from the lower surface of the tracing stylus 32. Hole 57
And are respectively engaged with tapered surfaces 58 formed at the inner ends of the center holes 56 and 57. The small-diameter center holes 52 and 53 are provided at the centers of the tapered surfaces 58, respectively.

As described above, the four sides of the tracing stylus 32 are surrounded by the frame-shaped non-magnetic guide 33 and the non-magnetic plate 46, and the center of the measuring axis of the measuring device 21 and the center of the tracing stylus 32 are perpendicular to the work surface 11. When the tension is applied to the connecting wire 31, the connecting wire 31
The balls 54 arranged at both ends of the 31 are concentrically engaged with the center hole 52 at the tip of the measuring shaft 26 and the center hole 53 of the measuring element 32, and the center of the measuring shaft 26, the connecting wire 31 and the measuring element 32 As a result, the center of the tracing stylus 32 can always be pulled up vertically.

Next, the operation of this embodiment will be described.

The base plate 13 of the stand 12 is placed on the work surface 11 of the electromagnetic chuck, and the height position and the like of the measuring instrument guide 15 attached to the column 14 of the stand 12 are adjusted. A vertically movable measuring instrument 21 is pushed upward by a handle 22 along the guide 15.

When an upward force is applied to the measuring device 21, the connecting wire 32 is connected to the measuring element 32 attracted to the electromagnetic chuck working surface 11.
A tensile load acts on the measuring shaft 26 of the measuring device 21 via the 31, and a change in the tensile load is digitally displayed on the liquid crystal display unit 27 every moment.

When the probe 32 separates from the work surface 11 of the electromagnetic chuck due to a tensile load exceeding the limit of the magnetic attraction force, the tensile load suddenly decreases at that moment.
The maximum load value applied to 26 is held as it is digitally displayed on the liquid crystal display 27 of the measuring instrument 21 having the peak hold function. The maximum display value of the measuring device 21 at the moment when the tracing stylus 32 comes off from the work surface 11 is defined as the magnetic attraction force of the work surface 11.

The use of the measuring device of the present invention is not limited to the performance test of an electromagnetic chuck used for a surface grinding machine, but is widely used for measuring the magnetic attraction force of an electromagnet, a permanent magnet, or the like. It is.

[0025]

According to the present invention, the center of the measuring axis of the measuring instrument and the center of the measuring element are measured by the non-magnetic guide provided at the lower part of the measuring instrument supporting structure. Since center deviation can be prevented by always keeping the plane perpendicular to the surface, accurate magnetic attraction force measurement values can always be easily obtained. In addition, since a measuring device that displays the maximum load value is used, even beginners can easily obtain accurate magnetic attraction force measurement values from the maximum load value at the moment when the probe comes away from the magnetic attraction force measurement target surface. Thus, workability and reliability related to the measurement of the magnetic attraction force can be improved.

According to the second aspect of the present invention, the connecting portions between the both ends of the connecting member and the measuring shaft and the measuring element are automatically aligned by the balls. can do.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of a magnetic attraction force measuring device of the present invention.

FIG. 2 is a perspective view showing a non-magnetic guide mounting portion in the measuring device.

FIG. 3 is a cross-sectional view showing a connection portion at both ends of a connecting member in the measuring device.

FIG. 4 is a perspective view showing a conventional magnetic attraction force measuring means.

[Explanation of symbols]

11 Electromagnetic chuck working surface as the surface to be measured for magnetic attraction force 12 Stand as measuring device support structure 21 Measuring device 26 Measuring shaft 31 Connecting wire as connecting material 32 Measuring element 33 Non-magnetic guide 52 Center hole 53 Center hole 54 Ball

Claims (2)

(57) [Scope of request for utility model registration] 1. A measuring device support structure mounted on a surface to be measured for magnetic attraction force, and a magnetic attraction device provided above the measuring device support structure so as to be movable in a direction perpendicular to the surface to be measured for magnetic attraction force. A measuring instrument that measures the tensile load and displays the maximum load value with a measuring shaft that projects vertically toward the force measurement target surface, and that is connected concentrically to the tip of the measuring shaft of this measuring instrument via a connecting material and connected magnetically. A measuring element that is magnetically attracted to a surface to be measured for attracting force; and a non-magnetic guide that is provided below the measuring instrument support structure and that guides the measuring element movably while being concentric with the measurement axis. Magnetic attraction force measuring device. 2. The magnetic attraction according to claim 1, wherein both ends of the connecting member are engaged with a center hole of the measuring shaft and a center hole of the measuring element via balls fixed to the both ends. Force measuring device.