JP2013145181A - Hardening process evaluation device and method for evaluating hardening process - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hardening process evaluation device capable of highly accurately determining a level of hardening depth by a hardening process.SOLUTION: The hardening process evaluation device includes: voltage application means for applying an AC exciting voltage to exciting coils 45 and 55; receiving coils 46 and 56 capable of detecting an induced voltage and an induced current caused by an eddy current generated in an inspection object component 1 by application of the AC exciting voltage; and coordinate transformation means that measures an amplitude value of the induced voltage and a phase difference between the induced voltage and the induced current and transforms the amplitude value of the induced voltage and the phase difference into polar coordinates. The level of the hardening depth by the hardening process performed on the inspection object component 1 is determined on the basis of the polar coordinates.

Description

  The present invention relates to a quenching process evaluation apparatus and a quenching process evaluation method capable of accurately determining the degree of quenching depth by quenching process applied to a part to be inspected.

  Conventionally, as this type of quenching processing evaluation apparatus, an apparatus that evaluates the quenching depth of a component to be inspected nondestructively using an eddy current sensor has been proposed.

Japanese Patent No. 3087499 JP 2002-14081 A

In the apparatus disclosed in Patent Document 1, the correlation between the phase difference with respect to the AC excitation signal of the detection signal caused by the eddy current generated when the AC excitation signal is excited on the component to be inspected, and the actual hardened and hardened layer depth is obtained. By using the obtained regression line as a calibration curve, the hardening hardening layer depth is obtained from the phase difference, but the hardening hardening layer depth cannot be uniquely determined only by the phase difference of the detection signal with respect to the AC excitation signal. There is also an opinion (Patent Document 2).
In the case of induction hardening, as shown in FIG. 7, the distribution of the hardened layer depth is clear and can be determined by the apparatus disclosed in Patent Document 1, but in the case of carburizing and quenching, As shown in FIG. 8, the distribution of the hardened layer depth is gentle, and the measurement method as disclosed in Patent Document 1 has a problem that the variation becomes large and the determination becomes difficult. There was room for further improvement in determining the layer depth with high accuracy.

An object of the present invention is to provide a quenching treatment evaluation apparatus and a quenching treatment evaluation method that can accurately determine the degree of quenching depth by quenching treatment applied to a part to be inspected, and achieve at least a part of this object. The following measures were taken.
The quenching treatment evaluation apparatus of the present invention is
A quenching process evaluation device for evaluating a quenching process performed on a part to be inspected,
Voltage application means for applying an AC excitation voltage;
Detecting means capable of detecting induced voltage and induced current caused by eddy current generated in the inspection target component by applying the AC excitation voltage to the inspection target component by the voltage applying means;
Measuring means for measuring an amplitude value of the induced voltage and a phase difference between the induced voltage and the induced current;
Coordinate conversion means for converting the measured amplitude value of the induced voltage and the phase difference into polar coordinates;
Determination means for determining the degree of quenching depth by the quenching process applied to the inspection target component based on the polar coordinates;
It is a summary to provide.

  The quenching processing evaluation apparatus of the present invention detects induced voltage and induced current caused by eddy current generated when an AC excitation voltage is excited on a component to be inspected, and detects the amplitude value of the induced voltage, the induced voltage, and the induced voltage. The phase difference from the induced current is converted into polar coordinates, and the degree of quenching depth by the quenching treatment applied to the inspection target part is determined based on the converted polar coordinates, and the degree of quenching depth is accurately determined. be able to.

Further, in the quenching processing evaluation apparatus according to the present invention, the determination means determines the depth of the quenching process by determining in which region of the degree-specific regions that are set in advance is based on the degree of the quenching depth. It may be a means for determining the degree of the length.
By doing so, it is only possible to determine in which region of the different regions set in advance based on the degree of quenching depth, the degree of quenching depth can be easily determined.

Further, in the quenching processing evaluation apparatus for determining in which region of the degree-specific region the polar coordinate is, the degree-specific region is set based on a distribution of the polar coordinates for the plurality of parts to be inspected. You can also
By so doing, it is possible to easily set the degree-specific areas.

Further, in the quenching processing evaluation apparatus that determines in which region of the degree-specific region the polar coordinate is, the degree-specific region may be set only within the range of the standard value of the quenching depth. it can.
By so doing, it is possible to set the degree-specific area more easily.

Moreover, in the quenching treatment evaluation apparatus of the present invention, the determination means determines whether or not the polar coordinates are within a preset quenching depth standard range, and the polar coordinates are within the quenching depth standard range. It can also be a means for determining the degree of the depth of the quenching process only when it is determined.
By doing so, it is only necessary to determine the degree of the depth of the quenching process when the degree of the quenching depth by the quenching process is within the standard range, so that the determination can be made quickly.

In addition, in the quenching process evaluation apparatus of the specification that determines the degree of the depth of the quenching process only when it is determined that the polar coordinates are within the standard range,
The voltage application means is means capable of exciting the AC excitation voltage continuously in a time-division manner at a plurality of frequencies with respect to one part to be inspected.
The measuring means is a means for measuring a plurality of amplitude values of the induced voltages corresponding to the plurality of frequencies and a plurality of the phase differences corresponding to the plurality of frequencies,
The coordinate conversion means is means for converting the measured amplitude values of the induced voltages and the phase differences into polar coordinates,
The determination means may be means for determining the degree of the depth of the quenching process only when it is determined that all of the plurality of polar coordinates corresponding to the plurality of frequencies are within the standard range. .
In this way, the degree of the quenching layer depth can be determined more accurately.

Moreover, the quenching treatment evaluation method of the present invention is:
A quenching process evaluation method for evaluating a quenching process performed on a part to be inspected,
(A) applying an AC excitation voltage to the inspection target component;
(B) detecting an induced voltage and an induced current caused by an eddy current generated in the inspection target component by application of the AC excitation voltage;
(C) measuring the amplitude value of the induced voltage and the phase difference between the induced voltage and the induced current;
(D) converting the measured amplitude value of the induced voltage and the phase difference into polar coordinates;
(E) The gist is to determine the degree of quenching depth by the quenching treatment applied to the inspection target part based on the polar coordinates.

  According to the quenching evaluation method of the present invention, the induced voltage and induced current caused by the eddy current generated when the AC excitation voltage is excited on the inspection target component are detected, and the amplitude value and induced voltage of the induced voltage are detected. The phase difference between the current and the induced current is converted into polar coordinates, and the degree of quenching depth by the quenching treatment applied to the part to be inspected is judged based on the converted polar coordinates. Can be judged well.

It is a schematic block diagram of the quenching process evaluation apparatus 1. 3 is an electric circuit diagram schematically showing an electrical connection state of exciting coils 45 and 55 and receiving coils 46 and 56 in measuring jigs 4 and 5. FIG. It is a flowchart which shows an example of the program of the quenching layer depth evaluation process. FIG. 5 is a relationship diagram showing a relationship between induced voltage V and induced current I. It is a figure which shows an example of a hardened layer depth specification range map. It is a figure which shows an example of a quenching layer depth grade map. It is a figure which shows distribution of the hardened layer depth of induction hardening. It is a figure which shows distribution of the hardened layer depth of carburizing quenching.

Next, the form for implementing this invention is demonstrated using an Example.
FIG. 1 is a schematic configuration diagram of a quenching treatment evaluation apparatus 1.
In addition, in an Example, the case where a test object component is a gear is illustrated, and the grade of the hardening depth by the hardening process currently given to the tooth surface of the tooth part 2a of the gear 2 can be determined. In particular, it is a quenching treatment evaluation apparatus 1 that can accurately determine the depth of a quenching layer that has been subjected to carburizing and quenching that has been difficult to determine.

The quenching processing evaluation apparatus 1 according to the embodiment includes a measurement jig 4 that can set a gear 2 to be evaluated, which is a component to be inspected, and a measurement jig that can set a correction gear 3 that is used to suppress the influence of temperature to some extent. 5, the measuring jig 4 and the AC power source 6 electrically connected to the measuring jig 5, the measuring instrument 7 also electrically connected to the measuring jig 4 and the measuring jig 5, and the entire apparatus are controlled. The electronic control unit 8 is provided.
The gear 2 to be evaluated, which is a component to be inspected, has a shaft hole 2b formed at the center, and a carburizing and quenching process is performed on the tooth surface of the outer peripheral tooth portion 2a to form a hardened layer.
In the embodiment, the correction gear 3 is used in order to suppress the influence of temperature to some extent and improve the measurement accuracy. The correction gear 3 has the same shape as the gear 2 to be evaluated. In the embodiment, the shaft hole 3b is formed in the center, and the quenching treatment of the tooth surface of the outer peripheral tooth portion 3a is within the quenching layer depth standard range. Therefore, the median value was used. The correction gear 3 may be one that has not been quenched.

The measuring jigs 4 and 5 are made of the same material and have the same shape. For example, the base parts 41 and 51 made of nylon, the outer peripheral frames 42 and 52 made of nylon and formed in a cylindrical shape, and the outer circumference It consists of exciting coils 45 and 55 and receiving coils 46 and 56 installed in the frames 42 and 52.
Columnar convex portions 41a and 51a projecting upward are formed at the central portions of the base portions 41 and 51. The shaft holes of the gear 2 and the correction gear 3 to be evaluated on the outer circumferences of the convex portions 41a and 51a, respectively. It is possible to set the gear 2 and the correction gear 3 to be evaluated by fitting 2b and 3b.

The excitation coils 45 and 55 are coils made of a conductor, and generate induction currents (eddy currents) corresponding to the respective frequencies in the gear 2 and the correction gear 3 to be evaluated by applying AC voltages having a plurality of different frequencies. It is something to be made. The exciting coils 45 and 55 are installed concentrically with the outer peripheral frames 42 and 52 in the outer peripheral frames 42 and 52, and in the embodiment, are arranged at positions where the height from the base portions 41 and 51 is about 15 mm. To do.
The receiving coils 46 and 56 are configured as coils having the same characteristics as the exciting coils 45 and 55, and induced voltages V 1 and V 2 due to induced currents (eddy currents) generated in the gear 2 to be evaluated and the correction gear 3. Is detected. The receiving coils 46 and 56 are arranged concentrically with the exciting coils 45 and 55 inside the exciting coils 45 and 55. In the embodiment, the toothed portion 2a of the gear 2 to be evaluated and the correction gear 3 are set. It was supposed to be arranged near the center of the tooth width of 3a.

In order to adjust the positional relationship among the excitation coils 45 and 55, the reception coils 46 and 56, the gear 2 to be evaluated, and the correction gear 3, a ring-shaped spacer is provided between the base portions 41 and 51 and the outer peripheral frame pairs 42 and 52. 43 and 53 are disposed, and ring-shaped spacers 44 and 54 are disposed between the base portions 41 and 51 and the gear 2 and the correction gear 3 to be evaluated.
The positional relationships among the exciting coils 45 and 55, the receiving coils 46 and 56, the gear 2 to be evaluated, and the correction gear 3 are not limited to the above-described relationships, and are optimal depending on the shape and evaluation portion. The positional relationship is changed.

FIG. 2 is an electric circuit diagram schematically showing an electrical connection state of the exciting coils 45 and 55 and the receiving coils 46 and 56 in the measuring jigs 4 and 5.
As shown in FIG. 2, the exciting coils 45 and 55 are connected in series with each other and both ends thereof are connected to an AC power source 6 described later, thereby forming a closed circuit.
Further, the receiving coils 46 and 56 are connected in series with each other and both ends thereof are connected to the measuring instrument 7 to form a closed circuit.
Here, the winding method of each coil and the circuit configuration are such that when the gear 2 to be evaluated is not set in the measuring jig 4 (in the exciting coil 45 and the receiving coil 46) or the correction gear 3 is used as the gear 2 to be evaluated. Is designed so that the measuring instrument 7 outputs a value of 0 when a tissue or shape that completely matches is set.
In other words, the measuring instrument 7 has the induced voltage V1 caused by the induced current generated in the gear 2 to be evaluated and the induced voltage V2 caused by the induced current generated in the correction gear 3 of the induced current I1 and the induced current I2. The induced voltage V and the induced current I are measured as relative values. Thus, by measuring the induced voltage V and the induced current I as relative values (difference values), the influence of temperature can be suppressed to some extent.

The AC power source 6 is configured as a power source that generates an AC voltage having a predetermined frequency and having a predetermined frequency, and selectively supplies an AC voltage (AC excitation signal V1) having a plurality of frequencies to the excitation coils 45 and 55. The excitation signal lines 6a and 6b are electrically connected to both ends of the excitation coils 45 and 55 so as to be continuously applied in the division.
The electronic control unit 8 is configured as a microprocessor centered on the CPU 8a, and includes a ROM 8c for storing a processing program, a RAM 8b for temporarily storing data, and an input / output port (not shown) in addition to the CPU 8a. The induced voltage V and induced current I from the measuring instrument 7 are input to the electronic control unit 8 through the input port. Further, an application signal to the AC power source 6 is output from the electronic control unit 8 through an output port.

Next, the quenching layer depth evaluation process executed by the electronic control unit 8 of the quenching process evaluation apparatus 1 configured as described above will be described.
FIG. 3 is a flowchart showing an example of a quenching layer depth evaluation process program executed by the electronic control unit 8 in the quenching process evaluation apparatus 1. This processing program is stored in the ROM 8c.

When the quenching layer depth evaluation process is executed, the CPU 8a of the electronic control unit 8 first applies the AC power supply 6 to the excitation coils 45 and 55 so that AC voltages of a plurality of different frequencies are continuously applied in time division. An application signal is output (step S1).
Here, in the embodiment, a plurality of different frequencies are determined and set in advance by experimentation or the like so that it is easy to determine that they are poorly quenched. That is, when polar coordinates P (X, Y), which will be described later, in a hardened defective product are plotted on a quench layer depth standard range map, which will be described later, the polar coordinates P (X, Y) are the quench layer depth of the quench layer depth standard range map. A frequency is selected that is plotted at a position greatly deviating from the standard range M.

Next, a plurality of induced voltages V and induced currents I corresponding to the respective frequencies are read from the measuring instrument 7 (step S2), and the phase difference φ between the induced voltage V and the induced current I is determined for each frequency. It is obtained every time (step S3). And the process which converts the induced voltage V and phase difference (phi) corresponding to each frequency into the polar coordinate P (X, Y) is implemented (step S4).
FIG. 4 is a relationship diagram showing the relationship between the induced voltage V and the induced current I. As shown in FIG. 4, there is a phase difference φ between the induced voltage V and the induced current I, and polar coordinates P (X, Y between the amplitude value V1 of the induced voltage V and the phase difference φ. ) Is well known to correlate with the quenching layer depth, and therefore detailed description thereof is omitted. Here, X = V1cosφ and Y = V1sinφ.

When the polar coordinates P (X, Y) corresponding to the respective frequencies are thus obtained, processing for determining whether or not these polar coordinates P (X, Y) are within the hardened layer depth standard range M is executed (step S5). .
Here, the hardened layer depth standard range M is a non-defective product, that is, a polar coordinate P ′ (X ′, Y ′) is obtained for a plurality of gears 2 to be evaluated that are known to be within the hardened layer depth standard range. A hardened layer depth standard range is set from the distribution of the plurality of polar coordinates P ′ (X ′, Y ′) and stored in the ROM 8c in advance as a hardened layer depth standard range map. Is plotted, the polar coordinates P (X, Y) are within the hardened layer depth standard range M by plotting the polar coordinates P (X, Y) on the hardened layer depth standard range map stored in the ROM 8c. Judgment was made on whether or not.
The hardened layer depth standard range map is set for each frequency. The quenching layer depth standard range M was 0.65 mm to 0.90 mm in the examples. An example of the hardened layer depth standard range map is shown in FIG.
Note that the correction gear 3 used in the calculation of the polar coordinates P ′ (X ′, Y ′) is also used when creating a hardened layer depth degree determination map described later and determining the hardened layer depth in the future.

If it is determined that the polar coordinates P (X, Y) corresponding to each frequency are all within the hardened layer depth standard range M (0.65 mm to 0.90 mm), then the degree of the hardened layer depth is determined. The process to perform is executed (step S6).
Here, the degree determination of the hardened layer depth is determined by using a plurality of evaluation gears 1 within a hardened layer depth standard range (0.65 mm to 0.90 mm) and having a known hardened layer depth of a predetermined width ( For example, polar coordinates P ″ (X ″, Y ″) are obtained for each quenching layer depth of 0.05 mm, and polar coordinates P ′ for each quenching layer depth having a predetermined width (for example, 0.05 mm) are obtained. A region for each depth of the hardened layer having a predetermined width (for example, 0.05 mm) is set from the distribution of '(X ″, Y ″), and is stored in advance in the ROM 8c as a hardened layer depth degree map. When P (X, Y) is given, the polar coordinates P (X, Y) are plotted on the hardened layer depth degree map by plotting the polar coordinates P (X, Y) on the hardened layer depth degree map stored in the ROM 8c. The determination is made by determining which region the image belongs to.
In the embodiment, the quenching layer depth degree determination is not performed for all of a plurality of different frequencies, but is performed for one representative frequency. The representative frequency may be selected by selecting a frequency at which the boundary of each region becomes clear when the hardened layer depth degree map is created. An example of the hardened layer depth degree map is shown in FIG.

As shown in FIG. 6, the hardened layer depth degree map includes a region M1 having a hardened layer depth of 0.65 mm to 0.70 mm, a region M2 having a hardened layer depth of 0.70 mm to 0.75 mm, and a hardened layer depth. Area M3 having a thickness of 0.75 mm to 0.80 mm, area M4 having a quenching layer depth of 0.80 mm to 0.85 mm, area M5 having a quenching layer depth of 0.85 mm to 0.90 mm, and areas M1 to M5 NG region (region where the quenching layer depth is less than 0.65 mm and greater than 0.90 mm). In this way, the hardened layer depth degree map can be easily created and judged easily because only the hardened layer depth degree map is created based on the distribution of multiple polar coordinates with known hardened layer depths. It can be.
When the degree of quenching layer depth is determined in this way, the fact that the gear 2 to be evaluated is “non-defective” and the degree of quenching layer depth (for example, 0.65 mm to 0.70 mm) is output (step S7). On the other hand, in the determination of whether or not the polar coordinates P (X, Y) are within the hardened layer depth standard range M in step S5, the polar coordinates P (X, Y) are the hardened layer depth standards. When it is determined that the value is outside the range M, a message indicating “defective product” is output (step S8), and this process is terminated.

  According to the quenching processing evaluation apparatus 1 of the embodiment described above, the induced voltage V and the induced current I resulting from the difference between the eddy currents generated in the gear 2 to be evaluated and the correction gear 3 are measured, and the induced The phase difference φ between the voltage V and the induced current I is calculated, the induced voltage V and the phase difference φ are converted into polar coordinates P (X, Y), and the polar coordinates are set in any region on the hardened layer depth degree map. Since it is determined whether P (X, Y) belongs, the degree of the quenching layer depth can be determined easily and accurately. In addition, since the difference between the eddy currents generated in the gear 2 to be evaluated and the correction gear 3 is detected, the influence of temperature can be suppressed to some extent, and the measurement accuracy can be improved.

  Further, according to the quenching treatment evaluation apparatus 1 of the example, first, it is determined whether or not the polar coordinates P (X, Y) are within the quenching layer depth standard range, and are within the quenching layer depth standard range. Since only the degree of the quenching layer depth is determined, it can be quickly determined.

  Furthermore, according to the quenching treatment evaluation apparatus 1 of the embodiment, the quenching layer depth standard range map corresponding to a plurality of AC voltages of different frequencies is provided, and measured according to the AC voltages of a plurality of different frequencies. The degree of the quenching layer depth is determined only when all of the plurality of polar coordinates P (X, Y) are within the corresponding quenching layer depth specification range. That is, since the degree of the quenching layer depth is determined after confirming that the measured polar coordinates P (X, Y) are surely within the quenching layer depth specification range, the degree of the quenching layer depth is determined quickly and accurately. Can be determined.

  In the quenching treatment evaluation apparatus 1 of the example, first, it is determined whether or not the polar coordinates P (X, Y) are within the quenching layer depth standard range, and only when the quenching layer depth is within the quenching layer depth standard range. Although the degree of the depth is determined, the degree of the quenched layer depth may be directly determined without determining whether the depth is within the standard range of the quenched layer depth.

  In the quenching treatment evaluation apparatus 1 of the example, the region where the quenching layer depth degree can be determined only within the quenching layer depth standard range is set, but the quenching layer depth is also outside the quenching layer depth standard range. An area where the degree can be determined may be set. In this way, it is possible to estimate how far the standard deviates.

  In the quenching treatment evaluation apparatus 1 of the embodiment, an AC voltage having a plurality of different frequencies is applied to the excitation coils 45 and 55, but an AC voltage having a single frequency is applied to the excitation coils 45 and 55. There is no problem.

  In the quenching treatment evaluation apparatus 1 of the example, the correction gear 3 is such that the quenching treatment of the tooth surface of the tooth portion 3a is within the quenching layer depth standard range and is almost the median value. As long as it is within the range, for example, it may be the upper limit value or the lower limit value of the hardened layer depth standard range.

  In the quenching evaluation apparatus 1 of the embodiment, the correction gear 3 is used to suppress the influence of temperature to some extent, but the correction gear 3 may not be used.

  In the quenching processing evaluation apparatus 1 of the embodiment, the apparatus for evaluating the degree of quenching depth in the gears has been described. However, quenching processing of shaft members, bearings, and the like, in particular, the parts to be inspected that have been carburized and quenched are similarly quenched. It goes without saying that the degree of depth can be evaluated. In this case, the measurement jigs 4 and 5, the excitation coils 45 and 55, and the reception coils 46 and 56 may be formed in a shape, material, and arrangement corresponding to the inspection target component.

1 Quenching evaluation device 2 Gears (parts to be inspected)
2a, 3a Tooth part 3 Correction gear 4 Measurement jig (for gear)
5 Measuring jig (for correction gear)
6 Power supply 7 Measuring instrument 8 Electronic control unit 41, 51 Base part 42, 52 Outer frame body 45, 55 Excitation coil 46, 56 Reception coil

Claims (7)

A quenching process evaluation device for evaluating a quenching process performed on a part to be inspected,
Voltage application means for applying an AC excitation voltage;
Detecting means capable of detecting induced voltage and induced current caused by eddy current generated in the inspection target component by applying the AC excitation voltage to the inspection target component by the voltage applying means;
Measuring means for measuring an amplitude value of the induced voltage and a phase difference between the induced voltage and the induced current;
Coordinate conversion means for converting the measured amplitude value of the induced voltage and the phase difference into polar coordinates;
Determination means for determining the degree of quenching depth by the quenching process applied to the inspection target component based on the polar coordinates;
A quenching processing evaluation apparatus comprising:   The determination means is means for determining the degree of the depth of the quenching process by determining in which region of the degree-specific regions that are set in advance based on the degree of the quenching depth, the polar coordinates are present. The quenching treatment evaluation apparatus according to 1.   The quenching processing evaluation apparatus according to claim 2, wherein the degree-specific region is set based on a distribution of the polar coordinates for a plurality of parts to be inspected.   The quenching process evaluation apparatus according to claim 2 or 3, wherein the degree-specific region is set only within a range of a standard value of the quenching depth.   The determination means determines whether or not the polar coordinates are within a preset quenching depth standard range, and only when it is determined that the polar coordinates are within the quenching depth standard range, the depth of the quenching process. The quenching processing evaluation apparatus according to any one of claims 1 to 4, wherein the quenching processing evaluation apparatus is a means for determining the degree of the above. The voltage application means is means capable of exciting the AC excitation voltage continuously in a time-division manner at a plurality of frequencies with respect to one part to be inspected.
The measuring means is a means for measuring a plurality of amplitude values of the induced voltages corresponding to the plurality of frequencies and a plurality of the phase differences corresponding to the plurality of frequencies,
The coordinate conversion means is means for converting the measured amplitude values of the induced voltages and the phase differences into polar coordinates,
The said determination means is a means which determines the grade of the depth of the said quenching process, only when it determines with all the several said polar coordinates corresponding to the said several frequency being in the said specification range. Quenching evaluation device. A quenching process evaluation method for evaluating a quenching process performed on a part to be inspected,
(A) applying an AC excitation voltage to the inspection target component;
(B) detecting an induced voltage and an induced current caused by an eddy current generated in the inspection target component by application of the AC excitation voltage;
(C) measuring the amplitude value of the induced voltage and the phase difference between the induced voltage and the induced current;
(D) converting the measured amplitude value of the induced voltage and the phase difference into polar coordinates;
(E) A quenching process evaluation method for determining a degree of quenching depth by the quenching process performed on the inspection target part based on the polar coordinates.

Images