JP2007286017A - Gear meshing state evaluation method and apparatus - Google Patents

Abstract

A gear meshing state evaluation method and a gear meshing state evaluation device are provided that have a high correlation with noise when the gears are actually meshed and rotationally driven and can be quantitatively evaluated.
A gear meshing state evaluation method includes a tooth surface shape measuring step S100 for measuring a three-dimensional shape of a tooth surface 11a of a driving gear 11 and a three-dimensional shape of a tooth surface 12a of a driven gear 12, and a driving gear 11 A power spectrum creating step S200 for creating a power spectrum by performing two-dimensional Fourier transform on the three-dimensional shape of the tooth surface 11a and the three-dimensional shape of the tooth surface 12a of the driven gear 12, and each of the driving gear 11 and the driven gear 12 A difference power spectrum creating step S300 for creating a difference power spectrum by calculating a difference between the power spectra of the two, and a meshing state determining step S400 for judging a meshing state of the drive gear 11 and the driven gear 12 based on the difference power spectrum; Are provided.
[Selection] Figure 9

Description

  The present invention relates to a method and apparatus for evaluating the meshing state of gears.

  Conventionally, it is known that the meshing state of a gear has a close relationship with the noise and vibration generated when the gear rotates while meshing, and the noise and vibration during driving of a device equipped with the gear is reduced. For this purpose, methods for evaluating the meshing state of gears have been studied.

As such an evaluation method, a method of actually engaging and rotating the gear and evaluating the meshing state of the gear based on noise and vibration generated from the gear and other information is performed.
For example, as described in Patent Document 1.

  In the method described in Patent Document 1, a transmission error is caused by a rotary encoder provided on an input shaft and an output shaft while meshing a gear fitted on an input shaft and a gear fitted on an output shaft and actually rotating the gear. A signal is detected, and a noise component is removed from the transmission error signal by Fourier-transforming the detected transmission error signal, and the meshing state of the gear is evaluated.

  However, this method usually has a low workability because a pair of gears is actually set in a state of being engaged with each other in a state where they are meshed with each other, and these must be driven to rotate. There is a problem that it is not suitable for the purpose of evaluating with high accuracy.

As a method different from the above method, the meshing state of the gear is determined by measuring the shape of the tooth surface of the gear with a contact or non-contact shape measuring device and comparing the measurement result with the shape of the reference tooth surface. Evaluation methods are being considered. As a method of measuring with a non-contact type shape measuring apparatus, the method described in Patent Document 2 can be cited.
As the simplest example of such a method, there is a method of measuring a shape by scanning a specific part of the tooth surface of the gear once with a probe or a laser beam, but in this case, the measurement result obtained by scanning only once is obtained. It is difficult to say that it reflects the overall shape of the tooth surface of the gear, and the correlation between the measurement result and the noise and vibration when the gear is actually driven to rotate is not high.

  Therefore, the operation of scanning the tooth surface of the gear in the tooth height direction using a probe or laser light is performed a plurality of times while slightly shifting in the tooth direction, thereby measuring the three-dimensional shape of the entire gear tooth surface. A method for evaluating the meshing state of the gear by comparing the solid shape of the entire tooth surface with the solid shape of the reference tooth surface has been studied.

However, the gear determined to be non-defective by this method has an error within a predetermined range from the reference tooth surface, but the relative shape error when these gears mesh with each other is Some combinations may be larger. In such a case, the correlation between the evaluation result of the gear meshing state and the measurement result of noise and vibration when the gear is actually meshed is low, and as a result, the reliability of the evaluation result of the gear meshing state is reliable. There is a problem that the nature is not high.
JP-A-1-199132 Japanese Unexamined Patent Publication No. 7-71942

  In view of the situation as described above, the present invention has a high correlation with noise and vibration when the gear is actually meshed and rotationally driven, and a gear meshing state evaluation method capable of quantitative evaluation and a gear meshing state. An evaluation apparatus is provided.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

That is, in claim 1,
Tooth surface shape measuring step for measuring the three-dimensional shape of the tooth surfaces of the pair of gears,
A power spectrum creating step for creating a power spectrum by two-dimensional Fourier transform for each of the three-dimensional shapes of the tooth surfaces of the pair of gears measured in the tooth surface shape measuring step;
A differential power spectrum creating step of creating a differential power spectrum by calculating a difference in power spectrum for each of the pair of gears created in the power spectrum creating step;
An engagement state determination step of determining an engagement state of the pair of gears based on the difference power spectrum created in the difference power spectrum creation step;
It comprises.

In claim 2,
In the meshing state determination step,
When the frequency component in the tooth height direction of the differential power spectrum becomes a predetermined intensity or more, it is determined that the meshing state is bad.

In claim 3,
Tooth surface shape measuring means for measuring the three-dimensional shape of the tooth surfaces of the pair of gears,
A power spectrum creating means for creating a power spectrum by performing two-dimensional Fourier transform on each of the three-dimensional shapes of the tooth surfaces of the pair of gears measured by the tooth surface shape measuring means;
Differential power spectrum creating means for creating a difference power spectrum by calculating a difference in power spectrum for each of the pair of gears created by the power spectrum creating means;
Meshing state determining means for determining the meshing state of the pair of gears based on the differential power spectrum created by the differential power spectrum creating means;
It comprises.

In claim 4,
The meshing state determining means includes
When the frequency component in the tooth height direction of the differential power spectrum becomes a predetermined intensity or more, it is determined that the meshing state is bad.

  As effects of the present invention, the following effects can be obtained.

  In Claim 1, it is possible to evaluate quantitatively the meshing state of a pair of gears.

  In Claim 2, it is possible to evaluate quantitatively the meshing state of a pair of gears.

  In claim 3, it is possible to quantitatively evaluate the meshing state of the pair of gears.

  In Claim 4, it is possible to evaluate quantitatively the meshing state of a pair of gears.

Below, the evaluation apparatus 1 which is one Embodiment of the meshing state evaluation apparatus of the gear which concerns on this invention using FIG. 1 is demonstrated.
The evaluation device 1 is a device for evaluating the meshing state of the drive gear 11 and the driven gear 12 that are a pair of gears, and mainly includes a shape measuring device 20, a control device 30, and the like.

The driving gear 11 and the driven gear 12 are an embodiment of a pair of gears according to the present invention, and are a pair of helical gears that can mesh with each other.
The gear according to the present invention is not limited to the helical gear such as the driving gear 11 and the driven gear 12 of the present embodiment, but is a spur gear, an internal gear, a rack, a straight bevel gear, a Hasuba bevel gear, a crown gear, The present invention can be applied to various gears such as a face gear, a zero roll bevel gear, a spiral bevel gear, a hypoid gear, a screw gear, and a worm gear.

The shape measuring device 20 is an embodiment of the tooth surface shape measuring means according to the present invention, and more specifically, the three-dimensional shape of the driving gear 11 and the driven gear 12, more precisely, the three-dimensional shape and the surface of the tooth surface 11 a of the driving gear 11. The three-dimensional shape of the tooth surface 12a of the drive gear 12 is measured.
The shape measuring device 20 is a contact-type shape measuring device and includes a probe 21.
The shape measuring device 20 scans the probe 21 while making contact with the tooth surface 11a of the driving gear 11 and the tooth surface 12a of the driven gear 12, so that the tooth surface 11a and the unevenness of the tooth surface 12a, that is, the tooth surface 11a and the tooth surface. The profile of the tooth surface shape of the surface 12a is acquired.
At this time, as shown in FIG. 2 (a), the shape measuring device 20 slightly scans the probe 21 in the tooth height direction (the gear tooth height direction) in the tooth width direction (the gear tooth width direction). A plurality of tooth profile profiles having different coordinates in the tooth width direction are obtained as shown in FIG.
In this way, the shape measuring apparatus 20 measures the three-dimensional shapes of the tooth surface 11a and the tooth surface 12a by acquiring a plurality of tooth surface shape profiles having different coordinates in the tooth width direction.

The shape measuring device 20 of the present embodiment is a contact-type shape measuring device, and the three-dimensional shape of the tooth surface 11a and the tooth surface 12a is obtained by acquiring a plurality of tooth surface shape profiles having different coordinates in the tooth width direction. However, the tooth surface shape measuring means according to the present invention is not limited to this, and any other structure may be used as long as the three-dimensional shape of the tooth surface of the gear can be measured.
Other configurations of the tooth surface shape measuring means according to the present invention include a non-contact type three-dimensional shape measuring device, for example, using an optical method such as laser light irradiation, or projecting a lattice pattern or the like onto the tooth surface. In addition, there is an apparatus that measures a three-dimensional shape of a tooth surface by processing an image captured by an imaging unit such as a camera.

  The control device 30 is a device for controlling various operations of the evaluation device 1. The control device 30 includes a control unit 31, an input unit 32, a display unit 33, and the like.

The control unit 31 is essentially a program (operation control program) for performing the operation of the evaluation apparatus 1, a program (power spectrum creation program) related to creation of power spectra of the tooth surface 11a and the tooth surface 12a described later, Storage means for storing a program (difference power spectrum creation program) relating to creation of a differential power spectrum, which will be described later, a program (meshing state judgment program) relating to determination of the meshing state of the tooth surface 11a and the tooth surface 12a, which will be described later, and the like An expansion means for expanding a program or the like, an operation means for performing a predetermined operation in accordance with these programs, a storage means for storing a power spectrum, an evaluation result, and the like are provided. More specifically, the control unit 31 may be configured such that a CPU, ROM, RAM, HDD, or the like is connected by a bus, or may be configured by a one-chip LSI or the like.
The control unit 31 may be a dedicated product, but can also be achieved by using a commercially available personal computer or workstation.

The control unit 31 is connected to the shape measuring device 20, can transmit a signal for operating the shape measuring device 20, and has a three-dimensional shape of the tooth surface 11a and the tooth surface 12a measured by the shape measuring device 20. It is possible to acquire the information concerning.
Details of the control unit 31 will be described later.

The input unit 32 is used by an operator or the like to input data relating to the operation of the evaluation apparatus 1 and the evaluation result to the control unit 31.
The input unit 32 may be a dedicated product, but can be achieved using a commercially available keyboard, touch panel, or the like.

The display unit 33 displays data input by the input unit 32, evaluation results, and the like.
The display unit 33 may be a dedicated product, but can also be achieved using a commercially available monitor, liquid crystal display, or the like.

Below, the detail of the control part 31 is demonstrated.
The control unit 31 includes a storage unit 31a, an operation control unit 31b, a power spectrum creation unit 31c, a differential power spectrum creation unit 31d, and a meshing state determination unit 31e.

The storage unit 31a stores various data such as the evaluation result of the meshing state of the driving gear 11 and the driven gear 12.
In the present embodiment, the various data is stored in the storage means (HDD or the like) of the control unit 31, thereby fulfilling the function as the storage unit 31a.

The operation control unit 31b controls the operation of the evaluation device 1.
In the present embodiment, a function (operation control program) for performing the operation of the evaluation device 1 stored in the storage unit of the control unit 31 is executed, thereby functioning as the operation control unit 31b.

The power spectrum creation unit 31 c is an embodiment of the power spectrum creation means according to the present invention, and the three-dimensional shape of the tooth surface 11 a of the driving gear 11 and the tooth surface 12 a of the driven gear 12 measured by the shape measuring device 20. The three-dimensional shape is subjected to two-dimensional Fourier transform, and power spectra in the tooth height direction and the tooth width direction as shown in FIGS. 3 and 4 are created.
In the present embodiment, a program (power spectrum creation program) related to creation of the power spectrum of the tooth surface 11a and the tooth surface 12a stored in the storage means of the control unit 31 is executed, so that the power spectrum creation unit 31c Fulfills the function.

  The power spectrum creation unit 31c performs two-dimensional Fourier transform on the information related to the three-dimensional shape of the tooth surface 11a of the drive gear 11, that is, the aggregate of the tooth surface shape profile of the tooth surface 11a, and generates the tooth of the drive gear 11 shown in FIG. A power spectrum for the surface 11a is created.

Here, “two-dimensional Fourier transform” is one of information processing methods used in the field of image processing and the like, and generally three axes that are orthogonal to each other, the X axis, the Y axis, and the Z axis are set. In the generated three-dimensional coordinate system, the frequency characteristics of the three-dimensional wave traveling on the XY plane while vibrating in the Z-axis direction, the frequency characteristics of the two-dimensional wave obtained by projecting the three-dimensional wave on the XZ plane, and the three-dimensional wave It is obtained as a combination of the frequency characteristics of the two-dimensional wave projected on the YZ plane.
As a two-dimensional Fourier transform technique, a known technique such as FFT (Fast Fourier Transform) can be employed.
“Frequency characteristics” represents the degree of coincidence (intensity) between a sine wave having a certain frequency and a target wave.
In addition, the “power spectrum” is on a plane whose vertical and horizontal axes represent the frequencies in two directions (X-axis direction and Y-axis direction) perpendicular to the vibration direction (Z-axis direction) of the two-dimensional Fourier transform, respectively. It represents the relationship between the combination of the frequency in the X-axis direction and the frequency in the Y-axis direction and the degree of coincidence (intensity) between the three-dimensional wave.

In the case of the present embodiment, as shown in FIG. 2, the power spectrum generator 31 c sets the tooth height direction as the X-axis direction, the tooth width direction as the Y-axis direction, and the tooth surface direction as the Z-axis direction. The three-dimensional shape of 11a is captured as a three-dimensional wave, and the frequency characteristics of the three-dimensional shape of the tooth surface 11a are obtained.
Next, based on the frequency characteristics of the three-dimensional shape of the tooth surface 11a, a power spectrum for the tooth surface 11a of the drive gear 11 as shown in FIG. 3 is created.
As shown in FIG. 3, in the case of the drive gear 11 of this embodiment, it can be seen that the intensity of the low frequency component is slightly large in both the tooth height direction and the tooth width direction.

Similarly, the power spectrum creation unit 31c captures the three-dimensional shape of the tooth surface 12a of the driven gear 12 as a three-dimensional wave, and obtains the frequency characteristics of the three-dimensional shape of the tooth surface 12a.
Next, based on the three-dimensional frequency characteristics of the tooth surface 12a, a power spectrum for the tooth surface 12a of the driven gear 12 as shown in FIG. 4 is created.
As shown in FIG. 4, in the case of the driven gear 12 of the present embodiment, the strength of the low frequency component is slightly large in both the tooth height direction and the tooth width direction, but is smaller than the strength of the low frequency component of the previous driving gear 11. I understand that.

The differential power spectrum creation unit 31d is an embodiment of the differential power spectrum creation unit according to the present invention, and the tooth surface 11a of the drive gear 11 and the tooth surface 12a of the driven gear 12 created by the power spectrum creation unit 31c. The difference power spectrum as shown in FIG. 5 is created by calculating the difference between the power spectra in the tooth height direction and the tooth width direction for each.
In the present embodiment, the function as the differential power spectrum creation unit 31d is achieved by executing a program (differential power spectrum creation program) related to creation of the differential power spectrum stored in the storage unit of the control unit 31.

The difference power spectrum creation unit 31d subtracts the power spectrum in the tooth height direction and the tooth width direction for the tooth surface 12a of the driven gear 12 from the power spectrum in the tooth height direction and the tooth width direction for the tooth surface 11a of the drive gear 11. That is, the difference in the degree of coincidence is calculated for each corresponding frequency combination.
Next, the difference power spectrum creation unit 31d represents the difference in the calculated degree of coincidence on a plane with the frequency in the tooth height direction as the vertical axis and the frequency in the tooth width direction as the horizontal axis, as shown in FIG. Create the differential power spectrum shown.
As shown in FIG. 5, in the case of the combination of the driving gear 11 and the driven gear 12 of the present embodiment, the strength of the low frequency component is large in both the tooth height direction and the tooth width direction, and particularly the strength of the low frequency component in the tooth height direction. You can see that it ’s big.

The meshing state determination unit 31e is an embodiment of the meshing state determination unit according to the present invention, and the meshing state of the drive gear 11 and the driven gear 12 is determined based on the differential power spectrum created by the differential power spectrum creation unit 31d. Judgment.
In the present embodiment, the engagement state determination unit 31e is executed by executing a program (engagement state determination program) related to determination of the engagement state of the tooth surface 11a and the tooth surface 12a stored in the storage unit of the control unit 31. Fulfills the function.
More specifically, the meshing state determination unit 31e determines whether the frequency component in the tooth height direction of the differential power spectrum, in particular, the low frequency component in the tooth height direction of the differential power spectrum is greater than or equal to a predetermined intensity. When it is determined that the meshing state of the driven gear 12 is poor and the low frequency component in the tooth height direction of the differential power spectrum is less than a predetermined strength, it is determined that the meshing state of the driving gear 11 and the driven gear 12 is good. .

  Hereinafter, the relationship between the differential power spectrum of the driving gear 11 and the driven gear 12 and the meshing state will be described with reference to FIGS.

  First, four drive gears 11, 11, 11, 11 and one driven gear 12 are prepared. At this time, four drive gears 11, 11, 11, 11 are prepared in advance with different three-dimensional shapes of the tooth surfaces 11 a. Hereinafter, the four drive gears 11, 11, 11, and 11 are referred to as drive gears A, B, C, and D, respectively. One driven gear 12 is referred to as a driven gear E.

Next, the three-dimensional shape of the tooth surface 11a (12a) is measured using the evaluation device 1 for the driving gears A, B, C, and D and the driven gear E, and a power spectrum is created for each.
Subsequently, using the evaluation apparatus 1, the combination of the driving gear A and the driven gear E, the combination of the driving gear B and the driven gear E, the combination of the driving gear C and the driven gear E, and the driving gear D and the driven gear A differential power spectrum for each of the combinations of E is created.
Finally, a combination of the driving gear A and the driven gear E, a combination of the driving gear B and the driven gear E, a combination of the driving gear C and the driven gear E, and a combination of the driving gear D and the driven gear E, respectively. Measures the sound that is generated when it is rotationally driven while actually engaging.

  FIG. 6 shows the frequency component in the tooth height direction at the lowest frequency in the tooth width direction of these differential power spectra (the degree of coincidence of the lines in the left and right directions at the substantially vertical center of the differential power spectrum shown in FIG. 5). Show.

  From FIG. 6, the combination of the driving gear A and the driven gear E has particularly higher strength of the low frequency component (portion surrounded by an ellipse in FIG. 6) than the other combinations.

  FIG. 7 shows the frequency component in the tooth width direction in the portion where the frequency in the tooth height direction is the lowest among these difference power spectra (the degree of coincidence of the vertical lines in the left and right central portions of the difference power spectrum shown in FIG. 5). Show.

From FIG. 7, the combination of the driving gear D and the driven gear E has a high strength from the low frequency component to the high frequency component, and the combination of the driving gear B and the driven gear E has a low strength from the low frequency component to the high frequency component.
In addition, the combination of the driving gear A and the driven gear E and the combination of the driving gear C and the driven gear E have high strength at the low frequency component but low strength at the high frequency component.

FIG. 8 shows a combination of the driving gear A and the driven gear E, a combination of the driving gear B and the driven gear E, a combination of the driving gear C and the driven gear E, and a combination of the driving gear D and the driven gear E. The measurement result of the sound generated when it is rotationally driven while actually engaging is shown.
From FIG. 8, the sound (sound pressure) generated when the combination of the drive gear A and the driven gear E is rotationally driven while actually engaging is larger than the other combinations over a wide frequency range.
Further, from FIG. 6, FIG. 7 and FIG. 8, the magnitude of the sound (FIG. 8) that is generated when actually rotating while meshing is the frequency component in the tooth height direction of the difference spectrum in the tooth height direction, In particular, it can be seen that there is a strong correlation with the intensity of the low frequency component (the part surrounded by an ellipse in FIG. 6).

6 to 8, whether or not the intensity (degree of coincidence) of the frequency component in the tooth height direction, particularly the low frequency component, of the differential power spectrum is equal to or greater than a predetermined intensity (whether it exceeds a predetermined threshold). By determining the meshing state of the drive gear 11 and the driven gear 12, that is, whether the noise is large when the drive gear 11 and the driven gear 12 are actually meshed and rotationally driven, Can be performed with high accuracy.
The “predetermined strength (predetermined threshold)” is the difference power spectrum created by the evaluation device 1 between the driving gear 11 and the driven gear 12 and the sound during actual rotational driving of the driving gear 11 and the driven gear 12. It is obtained in advance by repeatedly conducting an experiment for comparing the pressure.

In the present embodiment, the mesh state of the drive gear 11 and the driven gear 12 is evaluated using the frequency component in the tooth height direction of the differential power spectrum. However, the mesh state evaluation of the gear according to the present invention is performed. An apparatus is not limited to this, It is also possible to evaluate using the other element of a difference power spectrum according to the shape and kind of gear.
For example, it is possible to evaluate the meshing state of a pair of gears by using the frequency component in the tooth width direction or by comprehensively determining the frequency component in the tooth height direction and the frequency component in the tooth width direction. .
Further, in this embodiment, the direction of viewing the frequency characteristics of the power spectrum is two directions of the tooth height direction and the tooth width direction, but the gear meshing state evaluation device according to the present invention is not limited to this, and the shape of the gear and The direction of viewing the frequency characteristics of the power spectrum may be changed according to the type and the like.
For example, one of the directions for viewing the frequency characteristics of the power spectrum is the meshing traveling direction of the gears (the direction in which the contact portions of the tooth surfaces of the pair of gears move when the pair of gears are rotationally driven while meshing). It is good also as a structure including.

  The evaluation device 1 of the present embodiment is configured such that the power spectrum creation unit 31c, the difference power spectrum creation unit 31d, and the meshing state determination unit 31e are integrated, but the gear meshing state evaluation device according to the present invention is not limited thereto. Instead, the power spectrum creation unit 31c, the difference power spectrum creation unit 31d, and the meshing state determination unit 31e may be separate from each other.

  Below, one Embodiment of the meshing state evaluation method of the gear which concerns on this invention is described using FIG.

  One embodiment of the gear meshing state evaluation method according to the present invention is a method for evaluating the meshing state of the drive gear 11 and the driven gear 12 using the evaluation device 1, mainly the tooth surface shape measurement step S100, power spectrum. A creation step S200, a differential power spectrum creation step S300, and a meshing state determination step S400 are provided.

The tooth surface shape measuring step S100 is a step of measuring the three-dimensional shape of the tooth surface 11a of the drive gear 11 and the three-dimensional shape of the tooth surface 12a of the driven gear 12.
In the tooth surface shape measurement step S <b> 100, the shape measuring device 20 slightly scans in the tooth width direction while making the probe 21 contact the tooth surface 11 a of the drive gear 11 and the tooth surface 12 a of the driven gear 12. The three-dimensional shape of the tooth surface 11a of the driving gear 11 and the three-dimensional shape of the tooth surface 12a of the driven gear 12 are obtained by shifting a plurality of times and acquiring profiles of a plurality of tooth surface shapes having different coordinates in the tooth width direction. Measure each.
If tooth surface shape measurement process S100 is complete | finished, it will transfer to power spectrum creation process S200.

The power spectrum creation step S200 performs two-dimensional Fourier transform on the three-dimensional shape of the tooth surface 11a of the driving gear 11 and the three-dimensional shape of the tooth surface 12a of the driven gear 12 measured in the tooth surface shape measuring step S100, respectively. This is a step of creating a power spectrum in the tooth width direction.
In the power spectrum creation step S200, the power spectrum creation unit 31c sets the tooth height direction as the X-axis direction, the tooth width direction as the Y-axis direction, and the tooth surface direction as the Z-axis direction. The frequency characteristic of the three-dimensional shape of the tooth surface 11a is obtained by capturing the original wave.
Next, the power spectrum creation unit 31c creates a power spectrum for the tooth surface 11a of the drive gear 11 based on the three-dimensional frequency characteristics of the tooth surface 11a.
Similarly, the power spectrum creation unit 31c captures the three-dimensional shape of the tooth surface 12a of the driven gear 12 as a three-dimensional wave, and obtains the frequency characteristics of the three-dimensional shape of the tooth surface 12a.
Next, the power spectrum creation unit 31c creates a power spectrum for the tooth surface 12a of the driven gear 12 based on the three-dimensional frequency characteristics of the tooth surface 12a.
When the power spectrum creation step S200 ends, the process proceeds to the differential power spectrum creation step S300.

The difference power spectrum creation step S300 is a step of creating a difference power spectrum by calculating the difference between the power spectra for each of the drive gear 11 and the driven gear 12 created in the power spectrum creation step S200.
In the differential power spectrum creation step S300, the differential power spectrum creation unit 31d uses the power spectrum in the tooth height direction and the tooth width direction for the tooth surface 11a of the drive gear 11 and the tooth height direction for the tooth surface 12a of the driven gear 12 and The power spectrum in the tooth width direction is subtracted, that is, the difference in the degree of coincidence is calculated for each combination of the corresponding frequencies, and the difference in the degree of coincidence calculated is the frequency in the tooth height direction as the vertical axis and the tooth width direction. A differential power spectrum is created by expressing the frequency on a plane having the horizontal axis.
When the differential power spectrum creation step S300 is completed, the process proceeds to the meshing state determination step S400.

The meshing state determination step S400 is a step of determining the meshing state of the drive gear 11 and the driven gear 12 based on the differential power spectrum created in the differential power spectrum creation step S300.
In the meshing state determination step S400, the meshing state determination unit 31e drives the drive gear 11 when the frequency component in the tooth height direction of the differential power spectrum, in particular, the low frequency component in the tooth height direction of the differential power spectrum becomes equal to or greater than a predetermined intensity. When the low-frequency component in the tooth height direction of the differential power spectrum is less than a predetermined strength, it is determined that the meshing state of the driving gear 11 and the driven gear 12 is good. To do.
When the meshing state determination step S400 is finished, the embodiment of the gear meshing state evaluation method according to the present invention is finished.

As described above, one embodiment of the gear meshing state evaluation method according to the present invention is as follows.
A tooth surface shape measuring step S100 for measuring the three-dimensional shape of the tooth surface 11a of the driving gear 11 and the three-dimensional shape of the tooth surface 12a of the driven gear 12, and
A power spectrum creation step of creating a power spectrum by performing two-dimensional Fourier transform on the three-dimensional shape of the tooth surface 11a of the driving gear 11 and the three-dimensional shape of the tooth surface 12a of the driven gear 12 measured in the tooth surface shape measurement step S100. S200,
A differential power spectrum creation step S300 for creating a differential power spectrum by calculating a difference in power spectrum for each of the drive gear 11 and the driven gear 12 created in the power spectrum creation step S200;
An engagement state determination step S400 for determining the engagement state of the drive gear 11 and the driven gear 12 based on the difference power spectrum created in the difference power spectrum creation step S300;
It comprises.
With this configuration, it is possible to quantitatively evaluate the meshing state of the driving gear 11 and the driven gear 12 without actually driving the driving gear 11 and the driven gear 12 to be engaged and rotating. is there. In other words, when the drive gear 11 and the driven gear 12 are actually meshed and rotationally driven, it is possible to accurately determine whether or not the noise is large.
In particular, as in the conventional evaluation method, it is effective to generate a large noise or vibration when the gears determined to be within the allowable range compared to the reference gear are actually meshed and driven to rotate. It is possible to prevent.

An embodiment of the gear meshing state evaluation method according to the present invention is as follows:
In the meshing state determination step S400,
When the frequency component in the tooth height direction of the differential power spectrum becomes a predetermined intensity or more, it is determined that the meshing state is bad.
With this configuration, the meshing state of the drive gear 11 and the driven gear 12 can be easily and accurately evaluated.

Moreover, the evaluation apparatus 1 which is one embodiment of the gear meshing state evaluation apparatus according to the present invention includes:
A shape measuring device 20 for measuring the three-dimensional shape of the tooth surface 11a of the driving gear 11 and the three-dimensional shape of the tooth surface 12a of the driven gear 12;
A power spectrum creation unit 31c that creates a power spectrum by performing two-dimensional Fourier transform on the three-dimensional shape of the tooth surface 11a of the driving gear 11 and the three-dimensional shape of the tooth surface 12a of the driven gear 12 measured by the shape measuring device 20. When,
A difference power spectrum creation unit 31d that creates a difference power spectrum by calculating a difference in power spectrum for each of the drive gear 11 and the driven gear 12 created by the power spectrum creation unit 31c;
An engagement state determination unit 31e that determines the engagement state of the drive gear 11 and the driven gear 12 based on the difference power spectrum generated by the difference power spectrum generation unit 31d;
It comprises.
With this configuration, it is possible to quantitatively evaluate the meshing state of the driving gear 11 and the driven gear 12 without actually driving the driving gear 11 and the driven gear 12 to be engaged and rotating. is there. In other words, when the drive gear 11 and the driven gear 12 are actually meshed and rotationally driven, it is possible to accurately determine whether or not the noise is large.
In particular, as in the conventional evaluation method, it is effective to generate a large noise or vibration when the gears determined to be within the allowable range compared to the reference gear are actually meshed and driven to rotate. It is possible to prevent.

The meshing state determination unit 31e of the evaluation device 1 is
When the frequency component in the tooth height direction of the differential power spectrum becomes a predetermined intensity or more, it is determined that the meshing state is bad.
With this configuration, the meshing state of the drive gear 11 and the driven gear 12 can be easily and accurately evaluated.

The figure which shows one Embodiment of the meshing state evaluation apparatus of the gear which concerns on this invention. The figure which shows the tooth surface profile of a gearwheel. The figure which shows the power spectrum of the tooth surface of one gearwheel. The figure which shows the power spectrum of the tooth surface of the other gearwheel. The figure which shows a difference power spectrum. The figure which shows the relationship between the frequency component and the intensity | strength of the tooth height direction in a differential power spectrum. The figure which shows the relationship between the frequency component of the tooth width direction in a difference power spectrum, and intensity | strength. The figure which shows the relationship between the combination of a pair of gears, and the sound pressure at the time of rotational drive. The flowchart which shows one Embodiment of the meshing state evaluation method of the gearwheel which concerns on this invention.

Explanation of symbols

1 Evaluation device (gear meshing state evaluation device)
11 Drive gear (gear)
11a Tooth surface 12 Driven gear (gear)
12a tooth surface 20 shape measuring device (tooth surface shape measuring means)
31c Power spectrum creation unit (power spectrum creation means)
31d Difference power spectrum creation unit (difference power spectrum creation means)
31e meshing state determination unit (meshing state determination unit)

Claims (4)

Tooth surface shape measuring step for measuring the three-dimensional shape of the tooth surfaces of the pair of gears,
A power spectrum creating step for creating a power spectrum by two-dimensional Fourier transform for each of the three-dimensional shapes of the tooth surfaces of the pair of gears measured in the tooth surface shape measuring step;
A differential power spectrum creating step of creating a differential power spectrum by calculating a difference in power spectrum for each of the pair of gears created in the power spectrum creating step;
An engagement state determination step of determining an engagement state of the pair of gears based on the difference power spectrum created in the difference power spectrum creation step;
A method for evaluating the meshing state of a gear. In the meshing state determination step,
The gear meshing state evaluation method according to claim 1, wherein when the frequency component in the tooth height direction of the differential power spectrum is equal to or greater than a predetermined intensity, it is determined that the meshing state is bad. Tooth surface shape measuring means for measuring the three-dimensional shape of the tooth surfaces of the pair of gears,
A power spectrum creating means for creating a power spectrum by performing two-dimensional Fourier transform on each of the three-dimensional shapes of the tooth surfaces of the pair of gears measured by the tooth surface shape measuring means;
Differential power spectrum creating means for creating a difference power spectrum by calculating a difference in power spectrum for each of the pair of gears created by the power spectrum creating means;
Meshing state determining means for determining the meshing state of the pair of gears based on the differential power spectrum created by the differential power spectrum creating means;
A gear meshing state evaluation device comprising: The meshing state determining means includes
The gear meshing state evaluation device according to claim 3, wherein when the frequency component in the tooth height direction of the differential power spectrum becomes equal to or greater than a predetermined intensity, the meshing state is determined to be bad.

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