JPH11175793A - Surface shape detection sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To precisely detect the surface shape of a body to be measured without contact. SOLUTION: The tip of a rod type core 3 is arranged so as to move while facing the surface of an uneven body 10 to be measured in a magnetic field produced by an exciting coil 6, while the rod type core 3 is provided with a detection coil 5 for detecting magnetic flux variation generated due to the uneven shape of the body 10 be measured. The sensor sensitivity is improved by providing at different positions a step part 17 as a fitting support for the exciting coil 6 fitted surrounding the rod type core 3 and a groove 16 as a fitting support for the detection coil 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a sensor for detecting a surface shape. More specifically, the present invention relates to a surface shape detection sensor that detects unevenness on the surface of an object to be measured in a non-contact manner based on a change in magnetic flux.

[0002]

2. Description of the Related Art Conventionally, there is a dial gauge that can accurately measure the uneven shape of the surface of an object to be measured, has a simple structure and is inexpensive. However, since the dial gauge measures the object by fixing the object to be measured and bringing the probe into contact with the uneven surface, the measurement takes a long time. For this reason, it is difficult to instantaneously detect the uneven shape of the surface of the object to be measured, and it cannot be applied to the application of detecting the uneven shape of the surface of the moving object one after another.

[0003] As described above, there has been no device that has a simple structure and is inexpensive and can successively detect irregularities on the surface of the object to be measured in a non-contact manner. An identification device or the like includes a plurality of sensors to collect various types of data on inserted coins and determine the type and authenticity of coins. Here, there is an eddy current sensor as one of the sensors installed in the coin identification device. The eddy current sensor is installed to face the coin passage, and electrically detects a change in magnetic flux when the coin passes. That is, since the resistivity differs depending on the material and thickness of the coin, the eddy current loss differs for each coin. The eddy current sensor electrically detects the change of the magnetic flux due to the eddy current loss and outputs it. Therefore, the coin discriminating device judges the material, thickness, diameter, etc. of the inserted coin based on the change in the detection output of the eddy current sensor, and also judges data based on the detection output of other sensors. By comparing these results with data stored in advance, the type and authenticity of the inserted coin are determined.

[0004]

However, in recent years,
There is a demand for the development of an inexpensive surface shape detection device that can detect the uneven shape of the surface of the object to be measured in a non-contact manner and has a simple structure. For example, with regard to coin identification devices incorporated in vending machines, etc., in the current situation where forgery and forgery of coins are becoming more sophisticated, the type and type of coin based on the complex and fine irregularities attached to the surface of the coin There is a request to determine the authenticity.

Here, as a method for detecting the unevenness of the surface in a non-contact manner, a method of processing an image taken by a CCD camera or a method of irradiating a semiconductor laser onto the uneven surface and capturing the reflected light by a photodiode or the like. There are methods. However, in these methods, the rust and dirt on the uneven surface are all different, which is an obstacle to identification, and expensive devices dedicated to the uneven shape are separately provided to detect the uneven shape of the coin surface. Since it is installed, the production cost is increased and the size of the apparatus is increased, which is not appropriate. Furthermore, in the method of capturing an image with a CCD camera, the uneven shape is processed as planar image data, so that it is impossible to distinguish a fake coin on which a photograph of a real coin is attached, for example. On the other hand, when irradiating light at a shallow angle from the periphery to make it easier to obtain unevenness information optically, if the central part is depressed, it is difficult to obtain reflected light, and there is a danger that it may be mistaken for a hole and a hole may be mistaken. is there. Therefore, in the coin identification device and the like, the existing sensor for detecting the material and the like which has been conventionally provided is developed to enable non-contact detection of the uneven shape of the coin surface, and the coin surface and the data of the coin material and the like are used together. If it is possible to obtain data on the uneven shape, it is convenient.

The development of such a surface shape detection sensor is required not only for coin identification but also for other applications.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a surface shape detecting sensor which can detect irregularities on the surface of an object to be measured in a non-contact manner, has good sensitivity, has a simple structure, and can be manufactured at low cost. I do.

[0008]

In order to achieve the above object, according to the present invention, the tip of a rod-shaped core is movably opposed to an uneven surface of an object to be measured in a magnetic field generated by an exciting coil. A surface shape detection sensor comprising a rod-shaped core and a detection coil for detecting a magnetic flux change generated due to the uneven shape of the object to be measured, wherein the excitation coil is mounted so as to surround the rod-shaped core. And the mounting support for the detection coil are provided at different positions.

Since the output of the detection sensor section changes in accordance with the uneven shape of the surface of the object to be measured, the tip of the rod-shaped core is detected when the rod-shaped core is moved relative to the object to be measured. The uneven shape of the surface of the object to be measured can be detected by a change in the output of the section. Since the mounting support for the excitation coil and the support for mounting the detection coil are provided at different positions and these coils are arranged at different positions,
The output of the detection coil greatly changes as compared with a case where these coils are arranged at the same position. That is, the rate of change of the output of the detection coil can be increased.

Further, in the surface shape detecting sensor according to the second aspect, the different positions of the respective mounting supporting portions may be radial directions centering on the rod core or different positions in the length direction of the rod core. is there. Therefore, when the detection coil and the excitation coil are installed on each mounting support, the detection coil and the excitation coil are arranged apart from each other in the radial direction around the rod core or in the length direction of the rod core.

According to a third aspect of the present invention, there is provided a sensor for detecting a surface shape, wherein auxiliary cores for forming a magnetic flux path are disposed on both sides of the rod-shaped core, and a detection coil is wound around the rod-shaped core and the auxiliary core is provided. In which an exciting coil is wound. Therefore, an auxiliary core is formed separately from the rod-shaped core provided with the detection coil. By winding an excitation coil for generating a magnetic field through which the object to be measured passes around the auxiliary core, the auxiliary coil is formed. It can be arranged apart from the detection coil.

According to a fourth aspect of the present invention, there is provided a sensor for detecting a surface shape, wherein an auxiliary core for forming a magnetic flux path having a cylindrical shape is disposed around a rod-shaped core having a round bar shape, and a detection coil is wound around the rod-shaped core. And an exciting coil wound around the auxiliary core. Therefore, the profile of the cross section of the rod-shaped core and the auxiliary core is circular, and the uneven shape of the surface of the object to be measured is similarly measured regardless of the direction in which the relative movement between the object to be measured and each core is 360 degrees. can do.

According to a fifth aspect of the present invention, there is provided a sensor for detecting a surface shape, wherein a rod-shaped core and an auxiliary core are formed as an integral core body, and a detection coil installation groove is formed between the rod-shaped core and the auxiliary core. An excitation coil installation step is formed outside the auxiliary core. Therefore, the detection coil installation groove serves as a detection coil attachment support, and the excitation coil installation step serves as an excitation coil attachment support. That is, each coil is arranged at a position apart from the auxiliary core.

In the surface shape detecting sensor according to the present invention, a high-frequency signal is applied to the exciting coil. Therefore, the magnetic flux penetrating the DUT changes in a short period corresponding to the frequency of the high-frequency signal, and it is possible to detect fine irregularities.

Further, in the surface shape detecting sensor according to the present invention, the object to be measured is a coin, and the width of the tip in the relative movement direction of the tip of the rod-shaped core is 2 mm or less. Since the detection sensor unit detects a change in magnetic flux affecting the tip of the rod-shaped core, the resolution of the sensor is determined by the size of the tip surface of the rod-shaped core. The surface of the coin has fine irregularities, but the width of the tip of the rod-shaped core in the relative movement direction is set to 2 mm or less, so that the irregularities on the coin surface can be detected with the resolution required for discriminating coins. be able to.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described below in detail based on the best mode shown in the drawings.

FIG. 1 shows an example of an embodiment of a surface shape detecting sensor to which the present invention is applied. The surface shape detecting sensor 1 has the tip of the rod-shaped core 3 movably opposed to the surface of the uneven object 10 in the magnetic field generated by the exciting coil 6, and the rod-shaped core 3 A detection coil 5 for detecting a change in magnetic flux generated due to the uneven shape of the coil is provided, and a mounting support for the excitation coil 6 and a mounting support for the detection coil 5 are mounted so as to surround the rod-shaped core 3. They are provided at different positions.

Auxiliary cores 7 for forming a magnetic flux path are disposed on both sides of the rod-shaped core 3 therebetween. The rod-shaped core 3 and the two auxiliary cores 7 are constituted by an integral core body 2. I have. Between the rod-shaped core 3 and each auxiliary core 7, a detection coil installation groove 16 which is a support portion for mounting the detection coil 5 is formed, and outside the auxiliary core 7, a support for mounting the excitation coil 6 is provided. An exciting coil installation step 17 is formed. That is, the mounting supporting portions of the coils 5 and 6 are provided at different positions in the radial direction around the rod-shaped core 3.

The distances L3, L4 between the bottom 16a of the detection coil installation groove 16 and the excitation coil installation step 17 from the tip of the rod-shaped core 3 are different. In other words, the bottom 16a of the detection coil installation groove 16 and the excitation coil installation step 1
7 is formed differently. In the present embodiment, the detection coil installation groove 1 is smaller than the excitation coil installation step 17.
6 is formed near the tip of the rod-shaped core 3. Therefore, when the detection coil 5 is installed in the detection coil installation groove 16, the coil 5 is wound around the rod-shaped core 3, and the excitation coil 6 is connected to the excitation coil installation step 1.
7, the coil 6 is wound around the auxiliary core 7.
Protrudes toward the tip end of the rod-shaped core 3 by a distance t, and the rod-shaped core 3
The distance L1 from the tip of the rod-shaped core 3 to the excitation coil 6 is different from the distance L2 from the tip of the rod-shaped core 3 to the detection coil 5.

Assuming now that the relative movement direction of the DUT 10 is the direction of the arrow in the figure, the width w of the distal end face 3a of the rod-shaped core 3 in the moving direction, that is, the distal end face 3 of the rod-shaped core 3
Length w of two sides along the relative movement direction among four sides of a
Is set smaller than the width of the uneven shape to be detected. For example, when the DUT 10 is a coin, the coin 10
Is set to a value smaller than the width of the uneven shape of the surface, for example, a value of 2 mm or less. When the width w becomes larger than 2 mm,
This is because the resolution of detection is rough for the uneven shape of the surface of the coin 10 and it is difficult to detect a fine uneven shape, and the data used for discriminating the authenticity of the coin 10 is inferior in resolution. . However, the width w is not necessarily 2 m
It is not necessary to set the width w to an appropriate value according to the width of the uneven shape. In addition, when it is sufficient to roughly detect the uneven shape, it is not always necessary to set the width w to be smaller than the width of the uneven shape. The width w may be set to the calculated value.

That is, irregularities of various widths may be mixed depending on the irregularities to be detected. In this case, the width w of the rod-shaped core 3 is set based on the minimum width of the irregularities. I do. For example, when detecting the uneven shape of a one-yen coin shown in FIG. 22A, the minimum width is the convex portion of the edge as shown in FIG. Set w. By setting the width w to a smaller value based on the minimum width, it is possible to detect all the uneven shapes. By doing so, the rod-shaped core 3
Irrespective of whether the relative movement locus is the P-line or the Q-line shown in FIG. However, it is not necessary to set the width w to a value smaller than the value based on the convex portion of the edge. For example, when it is sufficient to detect the uneven shape of the pattern portion without detecting the shape of the convex portion of the edge In this case, the width w of the rod-shaped core 3 may be smaller than the smallest width among the widths of the concavo-convex shape of the pattern portion to be detected. For example, in the case of (B), the width w of the bar-shaped core 3 may be smaller than the width of the uneven shape to be detected, for example, W1, W2. In other words, it is only necessary to determine the width of the concave / convex shape to be detected to be detected and to make the width smaller than the width. In this case,
Asperities having a width of a size desired to be detected can be clearly detected, while rough shapes having a small width which need not be detected can be roughly grasped.

A circuit shown in FIG. 2 is connected to the surface shape detecting sensor 1. For example, a high-frequency signal 14 is applied to the excitation coil 6 to generate a magnetic field in a space where the device under test 10 relatively moves. When the DUT 10 passes through this magnetic field, the magnetic flux changes. The change in the magnetic flux depends on the distance between the tip end surface 3a of the rod-shaped core 3 and the DUT 10 or the DUT 10
Since the degree of the change varies depending on the material of the object 10, the output of the detection coil 5 changes according to the uneven shape and the material of the surface of the device under test 10. The output of the detection coil 5 is an amplifier circuit 11
After that, the signal is half-wave rectified by the detection circuit 12 and the peak hold circuit 13 and subjected to envelope detection, and becomes an output signal having a waveform proportional to the uneven shape of the device under test 10. In this case, the order of amplification and detection may be reversed. In addition,
When the DUT 10 is, for example, a metal, the DUT 1
Since the eddy current generated at 0 reduces the magnetic flux affecting the rod-shaped core 3, the output signal of the detection coil 5 changes. When the device under test 10 is, for example, a magnetic material, the device under test is Since the leakage of the magnetic flux from 10 decreases, the output signal of the detection coil 5 changes, and therefore,
The surface shape detecting sensor 1 of the present invention can detect the unevenness of the surface not only when the measured object 10 is a metal or the like but also when it is a magnetic material or the like.

In this surface shape detection sensor 1, if the positions of the detection coil installation groove 16 which is the support for mounting the detection coil 5 and the excitation coil installation step 17 which is the support for the excitation coil 6 are different. Therefore, the detection coil 5 and the excitation coil 6 are arranged apart from each other, and the rate of change of the detection output, that is, the sensor sensitivity can be improved.

As in the case where the detection coil 5 and the excitation coil 6 are spaced apart from each other, if the distance L1 from the tip of the rod-shaped core 3 to the excitation coil 6 and the distance L2 from the tip of the rod-shaped core 3 to the detection coil 5 are different. By doing so, the rate of change of the detection output, that is, the sensor sensitivity can be improved. In FIG.
The effect of the difference between the interval L1 and the interval L2 on the sensor sensitivity is shown. The projecting distance of the detecting coil 5 from the exciting coil 6 is t
(= L1−L2), where T is the width of the exciting coil 6, t
When the value of / T is 0 (L1 = L2), the detection output becomes the maximum value A but the sensor sensitivity becomes the minimum value B. Then, as the value of t / T increases or decreases, that is, the detection coil 5 is made to protrude greatly from the excitation coil 6 (L1>).
L2) or withdrawing the detection coil 5 largely inside the exciting coil 6 (L1 <L2), the detection output decreases while the sensor sensitivity increases. Since the detection output can be amplified by the amplifier circuit 11 shown in FIG. 2, the surface shape detection sensor 1 should be set so that the sensor sensitivity is good even if the magnitude of the detection signal is somewhat sacrificed. By setting the absolute value of t / T to, for example, 0.1 or more, it is possible to obtain a sensor having a large change rate of the output signal of the detection coil 5 and capable of capturing the surface shape of the device under test 10. Further, the detection coil 5 is connected to the detection coil installation groove 1.
6 and the exciting coil 6 is connected to the exciting coil setting step 17.
, The relative positional relationship between the coils 5 and 6 is accurately regulated, and the distance between the coils 5 and 6 and t
A change in the value of / T can be prevented, and the sensor sensitivity can be stabilized.

Next, the outline of the manufacturing process of the surface shape detecting sensor 1 of the present invention is shown in FIG. First, the groove 18a and the step 18b are machined into the ferrite block 18 shown in (a) to obtain the state shown in (b), and the ferrite block 18 is cut into an appropriate thickness and shown in (c). Thus, the core body 2 is manufactured. The groove 18a is the groove 16 for installing the detection coil.
The step 18b becomes the step 17 for installing the exciting coil. Then, as shown in (d), the detection coil 5 and the excitation coil 6
Is installed.

The surface shape detecting sensor 1 configured as described above is arranged so that the measured object 10 relatively moves in the magnetic field generated by the exciting coil 6. For example, when used as a coin identification sensor incorporated in a coin identification device or the like of a vending machine, the surface shape detection sensor 1 is arranged near a coin passage, and a high-frequency signal of 1 MHz, for example, is output to the excitation coil 6 as a high-frequency signal. Apply a signal. Then, when the coin 10 as an object to be measured passes while opposing the distal end face 3a of the rod-shaped core 3, an output signal shown in FIG. 5, for example, is obtained. This output signal becomes low corresponding to the convex portion of the coin 10 and becomes high corresponding to the concave portion. Further, until the coin 10 is opposed to the rod-shaped core 3, the output is further higher than in the case where the coin 10 corresponds to the concave portion. If the coin 10 has a hole in the middle, the same high output can be obtained. In other words, the waveform of the output signal corresponds to the uneven shape of the surface of the coin 10, but at the same time, information 2 about the difference in height between the edge and the center of the coin 10.
1. Information on edge width 22, information on diameter 2
3. Information 24 on the material and thickness can be obtained. Therefore, when used as a coin identification sensor, it is possible to simultaneously detect such information 21 to 24 in addition to the information on the surface irregularities. That is, in order to detect the uneven shape of the surface of the device under test 10,
There is no need to provide a dedicated sensor separately, and low cost and downsizing can be achieved. However, the use of the surface shape detection sensor 1 of the present invention as a coin identification sensor is merely an example, and it is a matter of course that the present invention is not limited to coin identification applications.

In the surface shape detecting sensor 1 of FIG. 1, the step 17 for installing the exciting coil is formed outside each auxiliary core 7, but as shown in FIG.
The formation of 7 may be omitted. In this case, the portion 7a of each auxiliary core 7 to which the excitation coil 6 is fixed becomes a mounting support for the excitation coil 6. Further, in the surface shape detection sensor 1 of FIG. 1, the bottom 16a of the detection coil installation groove 16 is formed closer to the tip of the rod-shaped core 3 than the excitation coil installation step 17 as shown in FIG. As described above, the excitation coil installation step 17 may be formed closer to the tip of the rod-shaped core 3 than the bottom 16 a of the detection coil installation groove 16. That is, in the surface shape detection sensor 1 of FIG. 1, the detection coil 5 is made to protrude (L1> L2) from the excitation coil 6, but the excitation coil 6 is detected as in the surface shape detection sensor 1 of FIG. It may be made to protrude from the coil 5 (L1 <L2). Further, in the surface shape detecting sensor 1 of FIG. 1, the auxiliary cores 7 are formed on both sides of the rod-shaped core 3, but the surface shape detecting sensor 1 (only the core body 2 is shown in FIG. 8) shown in FIG. As described above, the auxiliary core 7 may be formed only on one side of the rod-shaped core 3. Further, as in the core body 2 shown in FIG.
The return path core 8 may be formed outside the auxiliary core 7.

Next, a second embodiment of the surface shape detecting sensor 1 to which the present invention is applied will be described with reference to FIG. In the surface shape detecting sensor 1, the formation of the auxiliary core 7 is omitted, and the detection coil 5 and the excitation coil 6 are provided around the rod-shaped core 3. The rod-shaped core 3 is provided with a detection coil installation step 19 which is a support for mounting the detection coil 5 and an excitation coil installation step 17 which is a support for mounting the excitation coil 6 in a stepped shape, that is, the rod-shaped core 3. Are formed at different positions in the length direction. Therefore, when the detection coil 5 and the excitation coil 6 are installed on each of the steps 19 and 17, the distance between the detection coil 5 and the excitation coil 6 is t (L1-L2).
It is arranged only shifted.

However, it is not always necessary to form both the detection coil installation step 19 and the excitation coil installation step 17 on the rod-shaped core 3, and the excitation coil installation step 17 is formed as shown in FIG. The step portions 17 and 19 may be omitted as shown in FIG. In such a case, the portions 3b and 3c of the rod-shaped core 3 to which the respective coils 5 and 6 are fixed become the support for mounting the detection coil 5 or the support for mounting the exciting coil 6. Further, FIG.
As shown in FIG. 3, the exciting coil installation step 17 as the mounting support for the exciting coil 6 is made to extend in the longitudinal direction of the rod-shaped core 3 more than the detection coil installing groove 16 as the mounting support for the detection coil 5. The detecting coil 5 and the exciting coil 6 may be formed so as to be shifted from each other so as to be formed at different positions on the distal end side so that the interval L1 is smaller than the interval L2.

Next, a third embodiment of the surface shape detecting sensor 1 to which the present invention is applied will be described with reference to FIG. In the surface shape detecting sensor 1, the auxiliary core 7 has a cylindrical shape surrounding the periphery of the rod-shaped core 3. Also,
The rod-shaped core 3 has a round bar shape having a width, that is, a diameter w.
Between the rod-shaped core 3 and the auxiliary core 7, a detection coil installation groove 16 which is a support for mounting the detection coil 5 is provided.
An excitation coil installation step 17 which is a support portion for mounting the excitation coil 6 is formed on the outer periphery of each of them. That is, the detection coil installation groove 16 and the excitation coil installation step 17 are
The coils 5 and 6 are formed at different positions in the radial direction around the rod-shaped core 3, and the coils 5 and 6 are arranged apart from each other in the radial direction of the rod-shaped core 3. In the surface shape detecting sensor 1, the auxiliary core 7 has a cylindrical shape, and the rod-shaped core 3 has a round bar shape. Even if the relative movement direction between the DUT 10 and each of the cores 3 and 7 is any direction of 360 degrees, the unevenness of the surface of the DUT 10 can be measured with the same resolution. The bottom 16a of the detection coil installation groove 16
The step 17 for installing the exciting coil is formed in a stepped shape, and a distance L1 from the tip of the rod-shaped core 3 to the exciting coil 6 is formed.
Is the distance L2 from the tip of the rod-shaped core 3 to the detection coil 5.
Is bigger than.

However, the step 1 for installing the exciting coil is not necessarily required.
It is not necessary to form the step 7, and as shown in FIG. 15, the step 17 for installing the exciting coil may be omitted. In this case,
The portion 7a of the auxiliary core 7 to which the excitation coil 6 is fixed is a mounting support for the excitation coil 6. Further, the interval L2 does not necessarily need to be smaller than the interval L1, and the exciting coil 6 may be made to protrude from the detecting coil 5 so that the interval L1 may be smaller than the interval L2.

Next, a fourth embodiment of the surface shape detecting sensor 1 to which the present invention is applied will be described with reference to FIG. In the surface shape detection sensor 1, the detection coil 5
By interposing the spacer 9 between the coil and the exciting coil 6, the mounting support 32 of the detection coil 5 and the mounting support 33 of the excitation coil 6 are located at different positions in the radial direction around the rod-shaped core 3. Provided. By replacing the spacer 9 with a different size, the positional relationship of the rod-shaped cores 3 of the coils 5 and 6 in the radial direction can be adjusted.

The above embodiments are examples of preferred embodiments of the present invention, but are not limited thereto, and various modifications can be made without departing from the gist of the present invention. For example, it is not always necessary to make the interval L1 and the interval L2 different. If the support for mounting the detection coil 5 and the support for mounting the excitation coil 6 are provided at different positions, for example, as shown in FIG. The coils 5 and 6 may be arranged at the same height (L1 = L2).

In each of the above embodiments, the DUT 1
The relative movement direction of each core 3 is indicated by an arrow in each figure.
Although the direction along the line 7 is used, it is a matter of course that the uneven shape of the surface can be detected even if the relative movement direction of the DUT 10 is a direction other than the direction indicated by the arrow.

Instead of the detection coil 5 wound around the rod-shaped core 3, a magnetoresistive element attached to the rod-shaped core 3 may be used.

Further, the signal applied to the excitation coil 6 is not necessarily limited to a high-frequency signal, but may be a signal corresponding to the DUT 10 or its detection resolution. However, when used as a coin identification sensor, it is preferable to use an AC signal having a frequency of 1 kHz to 10 MHz. If the frequency is less than 1 kHz, the resolution of data for discriminating the type and authenticity of the coin is inferior. If the frequency exceeds 10 MHz, the impedance rises, driving the sensor becomes difficult, and the magnetic circuit becomes harder. This is because the jump noise between signal wirings that does not pass through increases.

[0037]

EXAMPLE In order to confirm that the sensor sensitivity is improved by making the interval L1 and the interval L2 different, the back side of a 500 yen coin is actually used by using the surface shape detecting sensor 1 shown in FIG. Was detected. When the value of t / T is 1 (L
1 ≠ L2). For comparison, the value of t / T is set to 0 (L
The same detection was performed with a surface shape detection sensor in which 1 = L2). The width w of the tip of the rod-shaped core 3 is 0.3 mm,
The frequency of the high-frequency signal 14 applied to the exciting coil 6 is 1 M
Hz. FIG. 18 shows the detection coil 5 when t / T = 1.
FIG. 19 shows the waveform of the output signal of the detection coil 5 when t / T = 0. As is clear from these figures, it was confirmed that by making the interval L1 and the interval L2 different, the sensor sensitivity was improved and the uneven shape could be more clearly detected.

Further, in order to investigate the relationship between the width w of the tip end surface 3a of the rod-shaped core 3 and the resolution for detecting the unevenness, an experiment was conducted in which the value of the width w was changed to detect the surface shape of a 500-yen coin. FIG. 20 shows the waveform of the output signal of the detection coil 5 when the width w is 0.5 mm, and FIG. 21 shows the waveform of the output signal of the detection coil 5 when the width w is 3 mm. 3m width w
m (FIG. 21), the shape of the output waveform becomes entirely flat, and information 21 on the height difference between the edge and the center of the 500-yen coin, information 2 on the diameter 2
3. Although information 24 and the like relating to the thickness of the material can be confirmed, it has been difficult to detect the uneven shape of the surface. In contrast, when the width w is 0.5 mm (FIG. 20), the change in the shape of the output signal follows the change in the surface shape of the 500-yen coin well. Thus, it was confirmed that by reducing the width w, it was possible to detect fine features of fine irregularities better. In addition, it was found that by setting the width w to 0.5 mm, it was possible to obtain a resolution sufficient for use as a sensor for discriminating the type and authenticity of coins.

[0039]

As described above, in the surface shape detecting sensor according to the first aspect, the mounting support for the excitation coil and the mounting support for the detection coil, which are mounted so as to surround the rod-shaped core, are located at different positions. Since the detection coil and the excitation coil are disposed apart from each other, the output of the detection coil greatly changes as compared with a case where each coil is arranged at the same position and the sensor sensitivity is changed. Can be improved. In addition, since a detection coil is provided on the rod-shaped core to detect a magnetic change caused by the uneven shape on the surface of the object to be measured, the structure of the sensor itself becomes simple, and the uneven shape is detected without contact. The sensor can be provided at low cost.

Further, in the surface shape detecting sensor according to the second aspect, the supporting portion for mounting the exciting coil and the supporting portion for mounting the detecting coil are radially centered on the rod-shaped core or in the length direction of the rod-shaped core. Since the coils are provided at different positions, by placing each coil on each mounting support portion, these coils are arranged radially around the rod core or in the length direction of the rod core, thereby reducing the sensor sensitivity. Can be improved.

In the surface shape detecting sensor according to the third aspect, auxiliary cores for forming a magnetic flux path are disposed on both sides of the rod-shaped core, and the detection coil is wound around the rod-shaped core and the auxiliary core is formed. Since the excitation coil is wound around the auxiliary coil, the excitation coil can be wound around the auxiliary core, and the excitation coil can be arranged away from the detection coil, so that the sensor sensitivity can be improved.

In the surface shape detecting sensor according to the present invention, an auxiliary core for forming a magnetic flux path having a cylindrical shape is disposed around a rod-shaped core having a round bar shape, and a detection coil is wound around the rod-shaped core. In addition, since the excitation coil is wound around the auxiliary core, the cross-sectional contours of the rod-shaped core and the auxiliary core can be made circular, and the relative movement direction between the object to be measured and each core is three.
In any direction of 60 degrees, the uneven shape of the surface of the object to be measured can be similarly measured.

Further, in the surface shape detecting sensor according to the fifth aspect, the rod-shaped core and the auxiliary core are constituted by an integral core body, and a detection coil installation groove is formed between the rod-shaped core and the auxiliary core. Since the excitation coil installation step is formed outside the auxiliary core, the detection coil installation groove serves as the detection coil attachment support, and the excitation coil installation step serves as the excitation coil attachment support. Is installed, the coil is disposed at a position distant from the auxiliary core.

In the surface shape detecting sensor according to the present invention, a high frequency signal is applied to the exciting coil.
The magnetic flux penetrating the DUT changes in a short period corresponding to the high-frequency signal, and it is possible to detect fine irregularities.

Further, in the surface shape detecting sensor according to the present invention, since the object to be measured is a coin and the width of the tip in the moving direction of the rod-shaped core is 2 mm or less, the resolution required for discriminating the coin is obtained. An uneven pattern on the coin surface can be detected.

[Brief description of the drawings]

FIG. 1 shows a first embodiment of a surface shape detection sensor to which the present invention is applied.
It is a perspective view which shows embodiment.

FIG. 2 is a circuit diagram connected to the surface shape detection sensor of the present invention.

FIG. 3 is a diagram illustrating a relationship between a value of t / T, a detection output, and a sensor sensitivity.

4A and 4B schematically show a manufacturing process of the surface shape detecting sensor of FIG. 1, wherein FIG. 4A is a perspective view of a ferrite block, and FIG.
Is a perspective view showing a state in which grooves and steps are machined in the ferrite block, (c) is a perspective view of a core body obtained by cutting the ferrite block, and (d) is a perspective view showing a state where a detection coil and an exciting coil are installed in the core body. FIG.

FIG. 5 is a diagram showing an example of an output signal of the surface shape detection sensor according to the present invention.

FIG. 6 is a perspective view showing a first modification of the surface shape detection sensor of FIG. 1;

FIG. 7 is a perspective view showing a second modification of the surface shape detection sensor of FIG. 1;

FIG. 8 is a perspective view showing a core body of a third modified example of the surface shape detection sensor of FIG. 1;

FIG. 9 is a perspective view showing a core body of a fourth modification of the surface shape detection sensor of FIG. 1;

FIG. 10 is a cross-sectional view showing a second embodiment of the surface shape detection sensor to which the present invention is applied.

FIG. 11 is a cross-sectional view showing a first modification of the surface shape detection sensor of FIG.

FIG. 12 is a side view showing a second modification of the surface shape detection sensor of FIG. 10;

FIG. 13 is a sectional view showing a third modification of the surface shape detecting sensor of FIG. 10;

FIG. 14 is a perspective view showing a third embodiment of a surface shape detection sensor to which the present invention is applied.

FIG. 15 is a perspective view showing a modification of the surface shape detection sensor of FIG. 14;

FIG. 16 is a sectional view showing a fourth embodiment of a surface shape detection sensor to which the present invention is applied.

FIG. 17 is a perspective view showing a fifth embodiment of a surface shape detection sensor to which the present invention is applied.

FIG. 18 is a diagram illustrating a surface shape detection sensor having a t / T value of 1;
It is a figure which shows the output signal at the time of measuring the uneven | corrugated shape of the back surface of a 00 yen coin.

FIG. 19 is a diagram illustrating a surface shape detection sensor having a t / T value of 0;
It is a figure which shows the output signal at the time of measuring the uneven | corrugated shape of the back surface of a 00 yen coin.

FIG. 20 is a diagram showing a sensor output in the case where the width w of the tip end surface of the rod-shaped core is set to 0.5 mm and an uneven pattern of a 500-yen coin is measured.

FIG. 21 shows a case where the width w of the tip end surface of the rod-shaped core is set to 3 mm and 50
It is a figure which shows the sensor output at the time of measuring the uneven | corrugated pattern of a 0 yen coin.

FIG. 22 is a view for explaining the relationship between the width w of the tip end surface of the rod-shaped core and the width of the uneven shape of the measured object;
FIG. 2A is a plan view of a one-yen coin (object to be measured), and FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Surface shape detection sensor 2 Core body 3 Bar-shaped core 3b Fixed part of detection coil (support part for mounting detection coil) 3c Fixed part of excitation coil (support part for mounting of excitation coil) 5 Detection coil 6 Excitation coil 7 Auxiliary Core 7a Fixed portion of excitation coil (support portion for mounting excitation coil) 10 Coin (measurement object) 14 High frequency signal 16 Groove for mounting detection coil (support portion for mounting detection coil) 17 Step portion for mounting excitation coil (excitation) (Supporting part for mounting coil) 19 Step part for installing detection coil (supporting part for mounting detection coil) 32 Supporting part for mounting detection coil 33 Supporting part for mounting excitation coil

Claims (7)

[Claims] In a magnetic field generated by an exciting coil, a tip of a rod-shaped core is relatively movably opposed to a surface of an object to be measured having irregularities, and the rod-shaped core is caused by the irregular shape of the object to be measured. A surface shape detection sensor provided with a detection coil for detecting a change in generated magnetic flux, wherein the support portion for mounting the excitation coil and the support portion for mounting the detection coil are mounted so as to surround the rod-shaped core. Is provided at a different position. 2. The surface shape detecting device according to claim 1, wherein the different position is a radial direction centered on the rod-shaped core or a position different in a length direction of the rod-shaped core. Sensor. 3. An auxiliary core for forming a magnetic flux path is disposed on both sides of the rod-shaped core, and the detection coil is wound around the rod-shaped core and the excitation coil is wound around the auxiliary core. The surface shape detection sensor according to claim 1 or 2, wherein: 4. An auxiliary core for forming a magnetic flux path having a cylindrical shape is disposed around the rod-shaped core having a round bar shape, and the detection coil is wound around the rod-shaped core, and the exciting coil is wound around the auxiliary core. The surface shape detecting sensor according to claim 1, wherein the sensor is wound. 5. The rod-shaped core and the auxiliary core are formed as an integral core body, and a detection coil installation groove is formed between the rod-shaped core and the auxiliary core, while an excitation coil is installed outside the auxiliary core. 5. The surface shape detecting sensor according to claim 3, wherein a step portion is formed. 6. The surface shape detecting sensor according to claim 1, wherein a high-frequency signal is applied to the exciting coil. 7. The surface shape detection sensor according to claim 6, wherein the object to be measured is a coin, and a width of the tip of the rod-shaped core in the relative movement direction is 2 mm or less.