JP2005180924A - Gear damage detector and gear damage detection method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gear damage detection method for specifying a damaged gear, in a gear transmission mechanism part comprising a plurality of gears. <P>SOLUTION: According to this damage detection method for a gear in a rotating drive device, made by connecting the gear transmission mechanism part, comprising the plurality of gears to the output shaft of a motor, a torque value and rotative speed of the motor are inputted, to calculate the fluctuation frequency of torque, then a torque value related to the fluctuation frequency is compared with a previously found threshold value to determine whether the torque value is anomalous, difference in the fluctuating frequency from a normal rotative frequency of each gear is found, when the torque value is determined to be anomalous; and then the difference in frequency is compared with an allowance of the rotative frequency of a relevant gear to determine that gear damage exists, when the difference in the frequencies is smaller than the allowance. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a gear breakage detection device and a gear breakage detection method provided in a rotary drive device having a plurality of gears.

  Some rotary drive devices have a gear transmission mechanism portion composed of a plurality of gears for reducing the rotational speed linked to the output shaft of the motor, and any gear is damaged when used. For example, when this rotary drive device is used for an object positioning mechanism, a problem arises. Therefore, in this type of rotary drive device, it is necessary to detect gear breakage.

By the way, as a method of detecting the breakage of the gear, it is conceivable to monitor the torque value of the motor, which is disclosed in Patent Document 1, for example.
This patent document 1 discloses a tool breakage detection method capable of detecting when some blades are broken in a tool having a plurality of blades.

This tool breakage detection method removes a specific frequency component of the disturbance load torque that is determined by the observer that calculates the disturbance load torque of the spindle motor from the torque command value and the speed feedback value, and the number of blades and the rotation speed of the tool. And a comparator that compares the output signal of the band cutoff filter with a predetermined reference value and outputs a signal indicating that the tool has been damaged when the output signal falls below the reference value. When the tool blade is damaged, the output signal removed by the band cutoff filter is attenuated, and this is monitored by the comparator.
Japanese Patent Laid-Open No. 7-51999 (refer to pages 2 to 5 and FIG. 1)

  However, according to the conventional method described above, it is possible to detect that the blade of the tool is damaged, but, for example, the configuration is not disclosed so that the damaged tool can be specified when there are a plurality of tools. Therefore, there is a problem that a damaged gear cannot be specified when there are a plurality of gears as in the gear transmission mechanism described above.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a gear breakage detection device and a gear breakage detection method that can identify a damaged gear in a gear transmission mechanism portion composed of a plurality of gears.

In order to solve the above problems, a gear breakage detection device of the present invention is a gear breakage detection device in a rotary drive device in which a gear transmission mechanism composed of a plurality of gears is connected to an output shaft of a motor. ,
A torque sensor and a speed sensor provided in the motor; a storage unit storing the number of teeth of each gear provided in the gear transmission mechanism;
A torque fluctuation frequency calculation unit for calculating a torque fluctuation frequency or fluctuation period (hereinafter referred to as a fluctuation frequency, etc.) by inputting a torque value from the torque sensor and a rotation speed from the speed sensor;
A torque value abnormality determination unit that determines whether or not the torque value is abnormal by comparing the torque value related to the torque variation frequency obtained by the torque variation frequency calculation unit and a preset threshold value;
When the torque value abnormality determining unit determines that the torque value is abnormal, the rotational speed from the speed sensor and the number of teeth of each gear are input from the storage unit, and the input rotational speed is A rotational frequency or rotation period (hereinafter referred to as a rotational frequency, etc.) and a permissible value for each gear according to the rotational frequency,
A difference calculation unit for sequentially inputting the torque fluctuation frequency and the like from the torque fluctuation frequency and the like calculation unit and the rotation frequency and the like from the rotation frequency and the like calculation unit to obtain the difference between these two frequencies,
This is composed of a gear breakage determination unit that compares the difference in frequency and the like obtained by the difference calculation unit with the obtained allowable value to determine whether or not the gear is broken.

A gear breakage detection method according to the present invention is a gear breakage detection method in a rotary drive device in which a gear transmission mechanism composed of a plurality of gears is connected to an output shaft of a motor.
The torque value and rotation speed of the motor are input to calculate the torque fluctuation frequency or fluctuation cycle (hereinafter referred to as fluctuation frequency, etc.)
Next, it is determined whether or not the torque value is abnormal by comparing the torque value related to the fluctuation frequency and the like with a predetermined threshold value.
When it is determined that the torque value is abnormal, the difference between the fluctuation frequency or the like and the rotation frequency or rotation cycle (hereinafter referred to as rotation frequency or the like) of each gear is obtained.
Next, the difference is compared with an allowable value such as a rotation frequency of each gear, and when the difference is smaller than the allowable value, it is determined that the gear is damaged.

  According to each of the above configurations, when a plurality of gears are provided and the torque value related to the fluctuation frequency is abnormal, the difference between the fluctuation frequency and the rotation frequency of each gear is compared, Since it is determined whether or not the rotational frequency of the gear is substantially the same, a damaged gear can be specified in the gear transmission mechanism having a plurality of gears.

[Embodiment]
Hereinafter, a gear breakage detection device and a gear breakage detection method in a rotary drive device according to an embodiment of the present invention will be described with reference to FIGS.

  The rotary drive device according to the present embodiment is provided in a data storage in which, for example, a plurality of magnetic tape cartridges are accommodated and a necessary magnetic tape is moved to a recording / reproducing unit. Will be described as being used as a drive source for a tape delivery mechanism in a moving device that moves the recording / reproducing unit.

  As shown in FIG. 1, the rotary drive device 1 includes a motor 2 and a drive input shaft portion (hereinafter also referred to as a driven shaft) of a tape holding portion in a tape delivery mechanism that is interlockedly connected to an output shaft 2a of the motor 2. A gear transmission mechanism 3 for rotating the motor 2 and a control device 4 for controlling the motor 2 based on a predetermined operation command.

  The control device 4 includes a program storage unit (ROM is used) 11 in which a system program is stored, and a data holding unit (an example of a storage unit that stores control data such as parameters necessary for various controls). 12), an arithmetic processing unit (consisting of a CPU) 13 for reading at least a program from the program storage unit 11 and executing various operation instructions, and a control command from the arithmetic processing unit 13 are input. A motor control circuit 14 for generating a motor control signal, a motor driver 15 for driving the motor 2 by inputting a control signal from the motor control circuit 14, and a torque from a torque sensor 16 provided in the motor 2. A torque detection circuit 17 that detects a torque value by inputting a signal, and a speed sensor 18 that is also provided in the motor 2. A rotation speed detection circuit 19 for detecting a rotation speed by inputting a degree signal, and the control device 4 includes a torque value and a rotation detected by the torque detection circuit 17 and the rotation speed detection circuit 19. A gear breakage detecting function for detecting breakage of the gear of the gear transmission mechanism section 3 based on the speed and data held in the data holding section 12 is provided. The configuration of the gear breakage detection device that realizes the gear breakage detection function will be described later.

Here, a configuration example of the gear transmission mechanism unit 3 will be described.
As shown in FIG. 2, the gear transmission mechanism unit 3 includes a gear between a driving side gear attached to the output shaft 2a of the motor 2 serving as a driving shaft portion and a driven side gear attached to the driven shaft. A case where four columns are arranged will be described.

  Hereinafter, specific examples of the number of teeth in the drive side gear, the input side gear and the output side gear in each gear train, and the driven side gear are shown in [Table 1] below.

すなわち、モータ２の出力軸２ａに取り付けられた駆動側歯車２１の歯数は１４、この駆動側歯車２１に噛合する第１歯車列の入力側歯車２２の歯数は５８でその出力側歯車２３の歯数は１４、この出力側歯車２３に噛合する第２歯車列の入力側歯車２４の歯数は５８でその出力側歯車２５の歯数は１４、この出力側歯車２５に噛合する第３歯車列における伝達歯車２６の歯数は６０、この伝達歯車２６に噛合する第４歯車列の入力側歯車２７の歯数は３０でその出力側歯車２８の歯数も３０で、この出力側歯車２８に噛合する被動軸３０に取り付けられた被動側歯車２９の歯数は３７６である。例えば、モータ２が７０００ｒｐｍで回転した場合には、第１歯車列は１６９０ｒｐｍで、第２歯車列は４０８ｒｐｍで、第３歯車列は９５ｒｐｍで、第４歯車列は１９０ｒｐｍで回転し、最後の被動側歯車２９は１５ｒｐｍでもって回転されることになる。

That is, the number of teeth of the drive side gear 21 attached to the output shaft 2a of the motor 2 is 14, the number of teeth of the input side gear 22 of the first gear train meshing with the drive side gear 21 is 58, and the output side gear 23 thereof. The number of teeth of the second gear train meshed with the output side gear 23 is 58, the number of teeth of the output side gear 25 is 14, and the number of teeth of the output side gear 25 is 14, the third number of meshing with the output side gear 25. The number of teeth of the transmission gear 26 in the gear train is 60, the number of teeth of the input side gear 27 of the fourth gear train meshing with the transmission gear 26 is 30, and the number of teeth of the output side gear 28 is 30. The number of teeth of the driven gear 29 attached to the driven shaft 30 that meshes with 28 is 376. For example, if the motor 2 rotates at 7000 rpm, the first gear train is 1690 rpm, the second gear train is 408 rpm, the third gear train is 95 rpm, the fourth gear train is rotated at 190 rpm, and the last driven The side gear 29 is rotated at 15 rpm.

  The gear breakage detection function detects the breakage of each gear described above (for example, tooth loss). As a principle of detection, if there is a broken gear, the rotation speed of the gear is detected. That is, attention is paid to the fact that the torque value fluctuates in accordance with the rotation frequency (or the reciprocal rotation period).

By the way, the gear breakage detection function is realized by software (program), and the gear breakage detection function realized by this software will be described below.
As shown in FIG. 3, the gear breakage detection function realized by this software inputs the torque value detected by the torque detection circuit 17 and the rotation speed detected by the rotation speed detection circuit 19 to input torque. Torque fluctuation frequency calculating section (or an example of a torque fluctuation frequency calculating section, which may be a torque fluctuation period calculating section) 31 for calculating a fluctuation frequency (or a reciprocal fluctuation period) of The torque value related to the fluctuation frequency obtained by the calculation unit 31 and a preset threshold value (an upper limit value (also referred to as a normal torque determination value) for determining that it is within the normal torque range), for example, the data holding unit 12 an abnormal torque value abnormality determination unit 32 that determines whether the torque value is abnormal, in the torque value abnormality determination unit 32 compares the held) (T _REF) to If it is determined, the rotational speed from the rotational speed detection circuit 19 and gear data (for example, data such as the gear number and the number of teeth in each gear) held in the data holding unit 12 are input to the motor. The normal rotation frequency (F _n ) (which may be the reciprocal of the rotation frequency) of each gear (drive side gear, gear in each gear train, driven side gear) n and its allowable value [ Gear rotation frequency calculation unit (an example of a calculation unit for gear rotation frequency etc.) that calculates (% of rotation frequency or rotation period (range of control stable region), for example, about 3% and is an allowable rotation frequency range) (F _A ) And the torque rotation frequency calculation unit 33) and the torque fluctuation frequency (F _V ) determined to be abnormal by the torque value abnormality determination unit 33 and the gear rotation frequency calculation. Difference calculation for calculating the difference (F _V −F _n ) from the normal rotation frequency (F _n ) in each gear (driving side gear, gear in each gear train, driven side gear) n obtained by the calculation unit 33 The frequency difference obtained by the unit 34 and the difference calculation unit 34 and the obtained allowable value (F _A ) (by comparing the absolute value of the frequency difference and the allowable value). And a gear breakage judgment unit 35 for judging whether or not is abnormal. In addition, the value calculated | required by each said calculating part is memorize | stored in the temporary memory part (for example, RAM is used) 20, for example as needed.

  Therefore, the gear breakage detection device includes the torque sensor 16, the speed sensor 18, the data holding unit 12, the torque fluctuation frequency calculation unit 31, the torque value abnormality determination unit 32, the gear rotation frequency calculation unit 33, and the difference calculation. It comprises a part 34 and a gear breakage judgment part 35.

The operation for detecting a damaged gear in the above configuration will be described with reference to the flowchart shown in FIG.
For example, when a gear breakage detection operation is started by the software during data storage maintenance, first, as shown in step 1, the torque value of the motor 2 is detected by the torque sensor 16 and the rotational speed of the motor 2 is detected by the speed sensor 18. It is detected and stored in the temporary storage unit 20. Since at least the torque value is detected as an analog value, it is stored as a digital value in an A-D conversion unit (not shown). In the detection operation, detection is performed by driving the motor 2 for a predetermined time. At this time, the rotational speed from the speed sensor 18 is input to the motor control circuit 14 and the rotational speed of the motor 2 is constant. Feedback control is performed so that

Next, as shown in step 2, the torque value and the rotational speed are input to the torque fluctuation frequency calculation unit 31, and the torque fluctuation frequency (F _V ) is obtained.
Next, as shown in step 3, the threshold value (T _REF ), which is a normal torque determination value held in advance in the data holding unit 12, is read out to the torque value abnormality determination unit 33, and is larger or smaller than the above torque value. Are compared.

In step 3, when the torque value is equal to or greater than the threshold value, it is determined that the torque value is abnormal, and the process proceeds to step 4 where the gear rotation frequency calculation unit 33 determines each gear during normal rotation of the motor 2. The rotational frequency and an allowable value (allowable rotational frequency) (F _A ) that is an allowable variation are obtained and held in, for example, the temporary storage unit 20.

In step 3, when the torque value is smaller than the threshold value, it is determined that the gear is not damaged and is normal.
Next, in step 5, in order to sequentially check the abnormality of the plurality of gears, the gear number n is set to 1, and then the process proceeds to step 6 where the gear number n exceeds the final number (total number of gears) N. If it is less than or equal to the final number N, the process proceeds to step 7.

In step 7, the difference calculation unit 34 obtains the difference (F _V −F _n ) between the fluctuation frequency (F _V ) of the torque value and the normal rotation frequency (F _n ) of the gear obtained in step 4. It is done.

Next, in Step 8, the absolute value of the frequency difference (F _V −F _n ) obtained in Step 7 and the allowable value (F _A ) related to the gear obtained in Step 4 by the gear breakage determination unit 35. Are compared to determine whether or not the gear is abnormal.

  In step 8, when the absolute value of the frequency difference is less than or equal to the allowable value, the torque fluctuation frequency substantially coincides with the rotation frequency of the gear in the normal state, and therefore the torque related to the fluctuation frequency. It is determined that the portion where the value is generated is the gear, and an output indicating that the gear is damaged is output.

For example, using the numerical values shown in [Table 1] (Note that in Table 1, the numerical values are RPM, but for the sake of simplicity, the numerical values are expressed here as frequencies (for example, 7000 RPM). 7000 cycles)), assuming that the torque fluctuation frequency (F _V ) is 400 cycles, the normal rotation frequency (F _n ) of the second gear train (gear 24 or 25) is 408 cycles. The absolute value (8 cycles) of the difference between the two frequencies is smaller than an allowable value (for example, about 14 cycles if it is several percent of 408 cycles, for example, 3%) (F _A ). It can be seen that the gears 24 or 25 in FIG.

  On the other hand, if the absolute value of the frequency difference is larger than the allowable value in step 8, it is found that the frequency of the variable torque is not the rotational frequency of the gear, and therefore it is determined that the gear is normal. After the gear number n is increased by 1 in step 9, the process returns to step 6 and steps 7 and 8 are executed to compare with the rotational frequency of the gear corresponding to the next number.

  If it is determined in step 8 that there is no breakage, the gear number is sequentially increased in step 9, but in step 6, the gear number n exceeds the total number N of gears. At that time (because all gears have been inspected), an output indicating that the gears in the gear transmission mechanism unit 3 are normal is output.

  Thus, when a plurality of gears are provided and the fluctuation torque value is abnormal, the difference between the fluctuation frequency of the torque and the normal rotation frequency of each gear is compared, and the fluctuation frequency and each Since it is determined whether or not the rotational frequency of the gear is substantially the same, the damaged gear can be specified in the gear transmission mechanism section 3 having a plurality of gears.

  In the above-described embodiment, the description has been made so as to detect the presence or absence of breakage of each gear among the plurality of gears, but the first to fourth gears provided with the input side gear and the output side gear. For a gear train, an abnormality of a gear provided in the gear train can be detected, but it cannot be specified whether the input side gear or the output side gear in the gear train is damaged.

  In the above embodiment, the case of detecting the breakage of the gear of the gear transmission mechanism of the mobile device in the data storage has been described. However, the configuration according to the present invention can also be applied to the following. .

  For example, when a DC brushless motor and a plurality of gear mechanisms are used for positioning, it is common to use an FG signal (motor rotation detection signal) obtained from the output of the Hall element when detecting the speed. And when counting and using the FG signal used for speed detection for positioning, by preparing another sensor in one place, the FG signal with the other sensor as the origin is used. Speed detection and positioning detection are possible. However, if the gear of the gear mechanism is damaged, the positioning position is deviated from the target position, resulting in a positioning error. However, a warning can be issued when the gear is detected to be broken. In addition, when the gear breakage position is a damage that has little influence on the positioning position, the normal operation is continued as it is despite the gear being damaged, or the operation is switched to another operation. Is also possible. As a specific example, when the mechanism to be driven is a rotating body, it is conceivable to adopt a configuration that crosses another sensor in one rotation. That is, it is considered that the total number of FG signals when the gear is damaged is larger than usual when compared with the total number of FG signals obtained by one rotation of the mechanism unit, and therefore is assumed when the gear is damaged. If the increment of the FG signal obtained from the amount of misregistration is the same, the increment of the FG signal due to the damage is added to the amount of the FG signal used for normal positioning when moving the position. In spite of being damaged, it is possible to maintain normal positioning accuracy. Further, when the mechanism portion is a rotating body, it is possible to maintain normal positioning accuracy by measuring the increase in the FG signal even if the gears at a plurality of locations are damaged.

  The gear breakage detection device and the gear breakage detection method according to the present invention use a motor because a broken gear can be identified in a rotary drive device in which a gear transmission mechanism having a plurality of gears is connected to a motor. However, it is useful in applications where gear breakage is a problem. In particular, when the motor is positioning, it is most suitable for an application that needs to avoid positioning errors and prompt the user of the apparatus.

It is a block diagram which shows schematic structure of the rotary drive device with which the gear breakage detection apparatus which concerns on this Embodiment was comprised. It is a schematic diagram which shows the specific example of the gear transmission mechanism part of the rotation drive device. It is a block diagram which shows the specific example of the gear breakage detection function in the rotation drive device. It is a flowchart explaining the gear breakage detection operation | movement in the rotation drive device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rotation drive apparatus 2 Motor 2a Output shaft 3 Gear transmission mechanism part 4 Control apparatus 11 Program memory | storage part 12 Data holding part 13 Operation processing part 16 Torque sensor 17 Torque detection circuit 18 Speed sensor 19 Rotation speed detection circuit 21 Drive gears 22-28 Gear 29 Driven gear 31 Torque fluctuation frequency calculation unit 32 Torque value abnormality determination unit 33 Gear rotation frequency calculation unit 34 Difference calculation unit 35 Gear breakage determination unit

Claims (2)

A gear breakage detection device in a rotary drive device in which a gear transmission mechanism composed of a plurality of gears is connected to an output shaft of a motor,
A torque sensor and a speed sensor provided in the motor; a storage unit storing the number of teeth of each gear provided in the gear transmission mechanism;
A torque fluctuation frequency calculation unit for calculating a torque fluctuation frequency or fluctuation period (hereinafter referred to as a fluctuation frequency, etc.) by inputting a torque value from the torque sensor and a rotation speed from the speed sensor;
A torque value abnormality determination unit that determines whether or not the torque value is abnormal by comparing the torque value related to the torque variation frequency obtained by the torque variation frequency calculation unit and a preset threshold value;
When the torque value abnormality determining unit determines that the torque value is abnormal, the rotational speed from the speed sensor and the number of teeth of each gear are input from the storage unit, and the input rotational speed is A rotational frequency or rotation period (hereinafter referred to as a rotational frequency, etc.) and a permissible value for each gear according to the rotational frequency,
A difference calculation unit for sequentially inputting the torque fluctuation frequency and the like from the torque fluctuation frequency and the like calculation unit and the rotation frequency and the like from the rotation frequency and the like calculation unit to obtain the difference between these two frequencies,
A gear breakage detecting device comprising: a gear breakage determining unit that compares the frequency difference obtained by the difference calculation unit with the obtained permissible value to determine whether the gear is broken or not. . A method for detecting a breakage of the gear in a rotary drive device in which a gear transmission mechanism composed of a plurality of gears is connected to an output shaft of a motor,
The torque value and rotation speed of the motor are input to calculate the torque fluctuation frequency or fluctuation cycle (hereinafter referred to as fluctuation frequency, etc.)
Next, it is determined whether or not the torque value is abnormal by comparing the torque value related to the fluctuation frequency and the like with a predetermined threshold value.
When it is determined that the torque value is abnormal, the difference between the fluctuation frequency or the like and the rotation frequency or rotation cycle (hereinafter referred to as rotation frequency or the like) of each gear is obtained.
Next, this difference is compared with an allowable value such as a rotation frequency in each gear, and if the difference is smaller than the allowable value, it is determined that the gear is damaged.

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