Determination method and determination program of gear working condition

Abstract

To provide a determination method of a gear working condition and a determination program of a gear working condition which can reduce vibration, in finishing of a gear.SOLUTION: A determination method of a gear working condition includes: a first step of measuring the shape of workpiece having a gear shape, and thereby acquiring a pitch error of the workpiece; a second step of performing frequency analysis of the pitch error, and thereby acquiring a rotation order component of a cumulative pitch error; a third step of multiplying the rotation order component of the pitch error by the number of rotation when the workpiece is worked, and thereby acquiring a frequency component of working load fluctuation by the pitch error; and a fourth step of setting the number of rotation when the workpiece is worked, so that a peak frequency of the working load fluctuation and resonance frequency of a gear working device are shifted from one another.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a method for determining gear machining conditions and a program for determining gear machining conditions. [Background technology]

[0002] In gear machining, finishing processes such as shaving and honing are performed (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-14124 Summary of the Invention [Problem to be solved by the invention]

[0004] However, it is known that depending on the gear shape, vibrations can increase during finish machining, making it difficult to achieve the required shape precision. The present invention has been made to solve the above problem, and its object is to provide a method for determining gear machining conditions and a program for determining gear machining conditions that can reduce vibrations during gear finish machining. [Means for solving the problem]

[0005] Item 1. A first step of measuring the shape of a gear-shaped workpiece to obtain the pitch error of the workpiece; a second step of acquiring rotational order components of the pitch error by frequency analyzing the pitch error; a third step of multiplying a rotational order component of the pitch error by the rotational speed when machining the workpiece, thereby acquiring a frequency component of a machining load variation due to the pitch error; a fourth step of setting a rotation speed when machining the workpiece so that a peak frequency of the machining load fluctuation and a resonance frequency of the gear machining device are shifted from each other; A method for determining gear machining conditions, comprising:

[0006] Item 2. A method for determining gear machining conditions according to Item 1, wherein in the fourth step, the rotation speed when machining the workpiece is set so that the peak frequency of the machining load fluctuation is higher than the resonance frequency of the gear machining device.

[0007] Section 3. Computer A first step of measuring the shape of a gear-shaped workpiece to obtain the pitch error of the workpiece; a second step of acquiring rotational order components of the pitch error by frequency analyzing the pitch error; a third step of multiplying a rotational order component of the pitch error by the rotational speed when machining the workpiece, thereby acquiring a frequency component of a machining load variation due to the pitch error; a fourth step of setting a rotation speed when machining the workpiece so that a peak frequency of the machining load fluctuation and a resonance frequency of the gear machining device are shifted from each other; Equipped with A program for determining gear machining conditions.

[0008] Item 4. A program for determining gear machining conditions according to Item 3, wherein in the fourth step, the rotation speed when machining the workpiece is set so that the peak frequency of the machining load fluctuation is higher than the resonance frequency of the gear machining device. [Effects of the Invention]

[0009] According to the present invention, vibrations can be reduced during finishing of gears. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a partial perspective view showing a schematic configuration of a gear machining device according to an embodiment of the present invention. FIG. [Figure 2] FIG. 2 is a block diagram of FIG. 1. [Figure 3] Graph showing cumulative pitch error of a workpiece. [Figure 4] 10 is a graph showing rotation order components of a cumulative pitch error of a workpiece. [Figure 5] 10 is a graph showing the relationship between the frequency of a workpiece and the processing load. [Figure 6] 1 is a graph showing the relationship between frequency and vibration of a gear machining device. [Figure 7] 1 is a graph showing the relationship between frequency and vibrations generated in a gear machining device during machining. [Figure 8] 10 is a graph showing the relationship between the frequency of a workpiece and the processing load. [Figure 9] 1 is a graph showing the relationship between frequency and vibrations generated in a gear machining device during machining. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, a gear machining device according to an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a partial perspective view showing a schematic configuration of the gear machining device according to this embodiment, and Fig. 2 is a block diagram of Fig. 1.

[0012] As shown in Figures 1 and 2, the gear processing device is a device that performs shaving, which is a finishing process for gears, and is equipped with a support unit 1 that supports an external gear-shaped workpiece W, which is the gear to be processed, and a processing tool unit 2 that has a processing tool for processing the workpiece W.

[0013] The support unit 1 includes a support table 11 that sandwiches the shaft portion W1 of the workpiece W, and a tailstock 12. The support table 11 includes a first shaft member 111 and a main body portion 112 that rotatably supports the first shaft member 111. On the other hand, the tailstock 12 includes a second shaft member 121 and a main body portion 122 that rotatably supports the second shaft member 121.

[0014] The first shaft member 111 and the second shaft member 121 are arranged in the same straight line as the shaft portion W1 of the workpiece W, and when the support table 11 and the tailstock 12 approach each other, the shaft portion W1 of the workpiece W is sandwiched between the first shaft member 111 and the second shaft member 121. Therefore, the main body portion 112 of the support table 11 and the main body portion 122 of the tailstock 12 are configured to be movable toward and away from each other. With this configuration, the support table 11 and the tailstock 12 can move in the feed direction Y while holding the workpiece W therebetween, and the workpiece W can be moved in the feed direction during machining.

[0015] The processing tool unit 2 includes an external gear-shaped processing tool 21 and a main body 22 that rotatably supports the processing tool 21. The main body 22 is configured to move the processing tool 21 toward and away from the workpiece W sandwiched between the support base 11 and the tailstock 12. The main body 22 also incorporates a reducer 221 and a spindle motor 222, and the main shaft of the spindle motor 222 is connected to the shaft 211 of the processing tool 21 via the reducer 221. The processing tool 21 is rotated by the spindle motor 222 and the reducer 221. That is, the main body 22 moves the processing tool 21 to mesh with the workpiece W (in the Z direction in FIG. 2 ), and the meshed processing tool 21 is rotated by the spindle motor 222, causing the workpiece W to rotate together. At this time, by driving the main body 22 and moving the processing tool 21 toward the workpiece W, the tooth surface of the workpiece W is ground (shaved). The shaft members 111, 121 of the support base 11 and the tailstock 12 are not driven, but rotate together with the rotation of the processing tool 21.

[0016] The main body 22 is also provided with a controller 23 that controls the driving of the processing tool 21 and the like.

[0017] The controller 23 can be configured by a PLC or a general-purpose computer having a CPU, RAM, and a storage unit, and controls the driving of the reducer 221 and the spindle motor 222.

[0018] Next, a method for determining the machining conditions will be described. The memory unit of the controller 23 stores a control program for driving the spindle motor 222, the reducer 221, etc. and determining the machining conditions, and a machining condition determination program. When these programs are loaded into the RAM, they are interpreted and executed by the CPU, and function as a computer having a software configuration including a rotation control unit 231 and a calculation unit 232. The rotation control unit 231 controls the rotation of the processing tool 21, and the calculation unit 232 performs calculations to determine the machining conditions. These will be described in detail below.

[0019] First, the outer shape of the workpiece W to be machined is measured, and the cumulative pitch error of the teeth is obtained in advance. This cumulative pitch error is then input into the calculation unit 232. FIG. 3 is a graph showing the obtained cumulative pitch error, with the horizontal axis representing the tooth number and the vertical axis representing the cumulative pitch error. Next, the calculation unit 232 performs frequency analysis such as a Fourier transform on the obtained cumulative pitch error to obtain the rotational order component of the cumulative pitch error, as shown in FIG. 4. FIG. 4 is a graph obtained as a result of the frequency analysis, with the horizontal axis representing the rotational order and the vertical axis representing the value of the rotational order component of the pitch error.

[0020] Next, the calculation unit 232 multiplies the rotational order component of the cumulative pitch error by the rotational speed of the workpiece during machining to determine the frequency component of the machining load fluctuation of the workpiece W due to the cumulative pitch error. The rotational speed of the workpiece W during machining is a preset rotational speed of the workpiece W, which is set as the initial value. Figure 5 is a graph obtained as a result, with the horizontal axis representing the frequency of the load fluctuation and the vertical axis representing the machining load. The machining load is an estimate of the frequency at which the load increases depending on the magnitude of the pitch error. In the example of Figure 5, a peak of the machining load appears near frequency X.

[0021] Meanwhile, the vibration characteristics of the gear cutting machine are acquired in advance and input to the calculation unit 232. FIG. 6 shows an example. In FIG. 6, the horizontal axis is frequency and the vertical axis is vibration (for example, in units of m / s 2) shows the resonant frequency of this gear cutting device. According to this graph, frequency Y is the resonant frequency of this gear cutting device. Therefore, for example, by multiplying the machining load of the workpiece W shown in FIG. 5 by the vibration of the gear cutting device shown in FIG. 6, it is possible to estimate the vibration that occurs in the gear cutting device when cutting this workpiece W, as shown in FIG. 7. In the example of FIG. 7, frequency X at which the peak of the machining load of the workpiece W appears roughly coincides with the resonant frequency Y of the gear cutting device, so vibrations in the vicinity of these frequencies X and Y become large during cutting.

[0022] Therefore, the results shown in Figure 7 are undesirable because large vibrations occur in the gear cutting device during cutting. Therefore, the calculation unit 232 increases the rotation speed of the workpiece W and recalculates the cutting load for each frequency. That is, the calculation performed when calculating Figure 5 above is performed. As a result, the frequency indicating the peak of the cutting load shifts to the higher frequency side, as shown in Figure 8. As a result, the frequency X indicating the peak of the cutting load deviates from the resonant frequency of the gear cutting device, thereby suppressing the generation of large vibrations. That is, by multiplying the cutting load of the workpiece W shown in Figure 8 by the vibration of the gear cutting device shown in Figure 6, the vibrations occurring in the gear cutting device when cutting the workpiece W can be obtained, as shown in Figure 9. In the example shown in Figure 9, the frequency X at which the peak of the cutting load of the workpiece W appears is different from the resonant frequency Y of the gear cutting device, so the vibrations occurring in the gear cutting device during cutting are dispersed, preventing large vibrations from occurring.

[0023] 9, in order to reduce vibrations generated in the gear machining device during machining, the calculation unit 232 sets the rotation speed of the workpiece so that the peak frequency of the machining load appears at a location, for example, about 5 to 30 Hz away from the resonance frequency. Once the rotation speed of the workpiece W is set by the calculation unit 232 in this way, the rotation control unit 231 performs machining in accordance with this.

[0024] If the vibration value shown in FIG. 7 or FIG. 9 is equal to or less than a predetermined threshold value, the rotation speed of the workpiece W is not reset, and processing is performed at the initial value of the rotation speed.

[0025] As described above, according to this embodiment, the frequency at which the machining load peaks is calculated based on the cumulative pitch error of the workpiece W, and the rotation speed of the workpiece W is set so that this frequency does not coincide with the resonance frequency of the gear machining device. This makes it possible to reduce vibrations of the gear machining device during machining, and as a result, improve machining accuracy.

[0026] Although one embodiment of the present invention has been described above, the present invention is not limited to this embodiment, and various modifications are possible without departing from the spirit of the present invention.

[0027] In the above embodiment, the rotation speed of the workpiece is increased to shift the frequency at which the peak of the machining load appears from the resonance frequency of the gear machining device, but it can also be decreased. Also, in the above embodiment, the machining conditions are determined using the cumulative pitch error as the pitch error, but a single pitch error can also be used.

[0028] In the above embodiment, the calculation for resetting the rotation speed of the workpiece W is performed by the controller of the gear processing device, but it is also possible to perform the calculation for resetting by a computer outside the gear processing device, and input the calculated rotation speed of the workpiece W into the rotation control unit to perform processing.

[0029] The support unit 1 and processing tool unit 2 for the workpiece W shown in the above embodiment are just examples, and are not particularly limited as long as they are configured to allow shaving or honing of the workpiece W while engaging the processing tool 21. [Explanation of symbols]

[0030] 1 Support Unit 2 Tool unit

Claims

1. a first step of measuring a shape of a gear-shaped workpiece to obtain a pitch error of the workpiece; a second step of acquiring rotational order components of the pitch error by frequency analyzing the pitch error; a third step of multiplying a rotational order component of the pitch error by a rotational speed when machining the workpiece, thereby acquiring a frequency component of a machining load variation due to the pitch error; a fourth step of setting a rotation speed when machining the workpiece so that a peak frequency of the machining load fluctuation and a resonance frequency of the gear machining device are different from each other; A method for determining gear machining conditions, comprising:

2. 2. The method for determining gear machining conditions according to claim 1, wherein in the fourth step, a rotation speed when machining the workpiece is set so that a peak frequency of the machining load fluctuation is higher than a resonance frequency of the gear machining device.

3. On the computer, a first step of measuring a shape of a gear-shaped workpiece to obtain a pitch error of the workpiece; a second step of acquiring rotational order components of the pitch error by frequency analyzing the pitch error; a third step of multiplying a rotational order component of the pitch error by a rotational speed when machining the workpiece, thereby acquiring a frequency component of a machining load variation due to the pitch error; a fourth step of setting a rotation speed when machining the workpiece so that a peak frequency of the machining load fluctuation and a resonance frequency of the gear machining device are different from each other; Equipped with A program for determining gear machining conditions.

4. 4. The program for determining gear machining conditions according to claim 3, wherein in the fourth step, a rotation speed when machining the workpiece is set so that a peak frequency of the machining load fluctuation is higher than a resonance frequency of the gear machining device.

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