JP4125204B2 - Detection torque correction method of magnetostrictive torque sensor - Google Patents

Description

  The present invention relates to a method for correcting a detected torque detected by a magnetostrictive torque sensor, and more particularly to a detected torque correcting method for a magnetostrictive torque sensor when the zero point of a torque detection shaft is not clear.

  There is a so-called magnetostrictive torque sensor that uses a change in a magnetic field to detect a torque applied to a shaft. This magnetostrictive torque sensor has a magnetostrictive ring made of a ferromagnetic material and a magnetic sensor. A magnetostrictive ring is press-fitted into a shaft to be detected by torque, and a change in magnetic field generated when torque is applied to the shaft is magnetized. The torque detected by the sensor and applied to the shaft is detected.

  In such a magnetostrictive torque sensor, the magnetization of the magnetostrictive ring cannot be made constant, and the residual stress at the time of press-fitting the magnetostrictive ring with respect to the axis varies depending on the part. Unevenness (hereinafter referred to as “regular unevenness”) occurs. Such regular unevenness causes measurement errors, and there is a torque sensor disclosed in JP-A-6-317493 as a technique for correcting the measurement errors.

This torque sensor detects the zero point variation due to the rotation angle when the torque of the torque detection shaft is not loaded, and stores it as zero point error data, and stores the zero point by the stored shaft rotation angle. The error data is read at the time of torque measurement, and the torque measurement value is corrected to correct the error due to regular unevenness.
JP-A-6-317493

  By the way, it can be considered that this type of magnetostrictive torque sensor is attached to a power transmission device or the like that connects the vehicle engine and the traveling device, and the torque of the engine is directly measured. If the torque sensor disclosed in Patent Document 1 is used as such a torque sensor, it is impossible to create a state in which the propeller shaft serving as the torque detection shaft is not loaded. Therefore, in this case, the method disclosed in Patent Document 1 cannot correct an error caused by regular unevenness.

  In addition, it may be assumed that the torque is not loaded when the load is light or when the fuel is cut, but in reality there is a load due to road load (load from the road), brakes or vehicle vibration. As a result, the torque cannot be applied.

  Accordingly, an object of the present invention is to provide a detection torque correction method of a magnetostrictive torque sensor that can correct an error due to regular unevenness even when a zero point cannot be grasped.

The present invention that has solved the above-described problems is a magnetostrictive torque that detects a magnetic field generated by a magnetostriction ring attached to a torque detection shaft including a shaft that transmits engine rotation in a vehicle , and detects the torque of the torque detection shaft. A method for correcting torque detected by a magnetostrictive torque sensor for correcting torque detected by a sensor, wherein the rotational speed of the torque detection shaft is detected, the magnetic field detected by the magnetic sensor is converted into a magnetic field signal, and the torque detection shaft Is converted into a rotation speed signal, the magnetic field signal and the rotation speed signal are supplied to the resonance circuit, the regular unevenness component of the magnetic field change detected by the magnetic sensor is extracted by the resonance circuit, and the regular unevenness component is removed. Then, the detected torque detected by the magnetostrictive torque sensor is corrected, and the detected torque correction method for the magnetostrictive torque sensor is provided.

  In the detected torque correction method according to the present invention, the rotational speed of the torque detection shaft and the magnetic field change in the magnetostrictive ring attached to the torque detection shaft are converted into electrical signals and supplied to the resonance circuit. In the resonance circuit, regular unevenness components are extracted from the electrical signals of these rotational speeds and magnetic field changes. Therefore, even when the zero point cannot be grasped, the regular unevenness component can be taken out and the regular unevenness component can be removed.

  Here, the resonance frequency in the resonance circuit can be set to an integer multiple of the rotation speed of the torque detection shaft.

  Alternatively, the resonance frequency in the resonance circuit may be set to a predetermined value, and the magnetic field may be detected by the magnetic sensor when the resonance frequency is an integral multiple of the rotation speed of the torque detection shaft.

  In any of these aspects, the regular unevenness component can be extracted by the resonance circuit from the electric signal of the rotation speed of the torque detection shaft and the change in the magnetic field.

Furthermore, the present invention that has solved the above-described problems detects a magnetic field generated by a magnetostriction ring attached to a torque detection shaft including a shaft that transmits engine rotation in a vehicle by a magnetic sensor, and detects torque of the torque detection shaft. A method for correcting torque detected by a magnetostrictive torque sensor that corrects torque detected by a magnetostrictive torque sensor, detecting the number of rotations of the torque detection shaft, and detecting by the magnetic sensor while the torque detection shaft rotates a plurality of times. Converting the magnetic field generated into a magnetic field signal, converting the rotational speed into a rotational speed signal, averaging the waveform of the magnetic field change at each rotation of the torque detection shaft detected by the magnetic sensor, and extracting a regular unevenness component, Compensating the detected torque detected by the magnetostrictive torque sensor by removing the regular unevenness component and correcting the detected torque of the magnetostrictive torque sensor It is a method.

  In the detected torque correction method according to the present invention, the regular unevenness component is obtained by averaging the waveform of the magnetic field change for each rotation of the magnetic field change detected by the magnetic sensor while the torque detection shaft rotates a plurality of times. Take out. Therefore, even when the zero point cannot be grasped, the regular unevenness component can be taken out and the regular unevenness component can be removed.

  Here, the rotation speed of the torque detection shaft is compared with the frequency of the magnetic field change detected by the magnetic sensor, and when the rotation speed of the torque detection shaft and the frequency of the magnetic field change detected by the magnetic sensor are shifted, It is preferable that the torque correction is stopped.

In addition, the regular unevenness component is calculated for each rotation of the magnetic sensor, the regular unevenness component is learned based on the regular unevenness component for each rotation of the calculated magnetic sensor, and is calculated for the learned regular unevenness component. More preferably, the torque correction is stopped when it is determined that the calculated regular unevenness component is abnormal because the regular unevenness component exceeds a predetermined threshold value .

  As described above, when the rotational speed of the torque detection shaft and the frequency of the magnetic change are different from each other or when there is an abnormality in the regular unevenness component with respect to the learned regular unevenness component, the torque correction is canceled to cancel the torque correction. Reliable torque detection can be reduced.

  Further, the number of rotations of the connected rotation shaft connected to rotate at a predetermined ratio with respect to the torque detection shaft is detected, and the number of rotations of the torque detection shaft is determined from the number of rotations of the connection rotation shaft and the predetermined ratio. It can be set as the aspect which calculates.

  For example, when a magnetostrictive torque sensor is provided on a propeller shaft that connects an engine and a drive system, the engine output shaft and the rotation speed of the propeller shaft are set to a predetermined ratio by a gear ratio interposed therebetween. The In such a state, even when the magnetostrictive torque sensor is not provided with a rotational speed sensor or the like, the rotational speed sensor provided in the engine detects the rotational speed of the engine output shaft, and the rotational speed and the gear ratio are detected. From the relationship, the rotation speed of the propeller shaft serving as the torque detection shaft can be calculated. Therefore, it is not necessary to provide a rotation speed sensor for measuring the rotation speed of the torque detection shaft.

  At this time, the waveform pattern indicating the magnetic field change detected by the magnetic sensor is stored, and the stored waveform pattern indicating the magnetic field change is compared with the newly detected waveform pattern indicating the magnetic field change. It is also possible to correct the deviation of the waveform indicating the newly detected magnetic field change.

  When calculating the rotation speed of the torque detection axis from the torque detection axis and the axis rotating at a predetermined ratio, if the relationship between the torque detection axis and the axis is deviated, the detected magnetic field change waveform is deviated. It is possible to end up. At this time, the waveform pattern indicating the magnetic field change detected by the magnetic sensor is stored, and the waveform pattern indicating the stored magnetic field change is compared with the newly detected waveform pattern indicating the magnetic field change. , Can understand the correct relationship.

Further, the rotational speed of the connected rotary shaft connected to rotate in a predetermined rotational rate change state with respect to the torque detection shaft is detected, and the rotation corresponding to the predetermined rotational rate change state is detected from the rotational speed of the connected rotary shaft. Subtract the number to obtain the approximate rotational speed of the torque detection shaft, and remove the unevenness component that is estimated to be other than the regular unevenness component within the predetermined range around the approximate rotational speed, and thus estimate the regular unevenness component It is possible to adopt a mode in which a component is extracted and a frequency at which a component estimated to be a regular unevenness component is determined as the rotation speed of the torque detection shaft.

  For example, in a so-called automatic vehicle, the engine and the traveling device are connected by a fluid coupling such as a torque converter. In this case, a change in the rotational speed accompanying a so-called slip (rotation rate change state) is observed between the output shaft of the engine and the propeller shaft. Further, although slip is involved, in that case, the range of the slip is limited to some extent, for example, 0 to 20%. For this reason, the approximate rotational speed, which is the approximate rotational speed of the torque detection shaft, is obtained from the range of the rotational rate change state, and the regular unevenness component is estimated within the approximate rotational speed range, so that the regular unevenness component is almost certainly confirmed. Uneven components can be extracted.

  At this time, it is possible to form a non-uniformity generating portion in the magnetostrictive torque sensor and detect the rotational speed of the torque detection rotating shaft.

  For example, if the regular unevenness component is too small, it may be difficult to confirm the approximate rotational speed. In preparation for this case, it is possible to provide an uneven member that causes unevenness in the torque detection shaft in advance. By providing this uneven member, it is possible to reliably grasp the rotational speed of the torque detection shaft by detecting a waveform corresponding to this uneven member.

  According to the present invention, it is possible to provide a detected torque correction method of a magnetostrictive torque sensor that can correct an error due to regular unevenness even when the zero point cannot be grasped.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In each embodiment, portions having the same function are denoted by the same reference numerals, and redundant description is omitted. In this embodiment, a case where a magnetostrictive torque sensor is attached to a propeller shaft of a vehicle will be described as an example.

  FIG. 1 is a block diagram for explaining a torque transmission state in a vehicle provided with a magnetostrictive torque sensor according to the present invention.

  As shown in FIG. 1, a magnetostrictive torque sensor (hereinafter referred to as “torque sensor”) 1 according to this embodiment is incorporated in a power train of a vehicle. The power train includes a power generation source 2, a first power transmission device 3, a second power transmission device 4, and a traveling device 5. The power generation source 2 includes an engine and the first power transmission device 3 includes a transmission and the like. The second power transmission device 4 includes a propeller shaft and the like, and the traveling device 5 includes a differential device, a drive shaft, wheels, and the like. The torque sensor 1 is provided between the first power transmission device 3 and the second power transmission device 4 and detects the torque of the engine.

  As shown in FIG. 2, the torque sensor 1 includes a magnetostrictive ring 11 and a magnetic sensor 12. The magnetostrictive ring 11 is a ring-shaped member made of a magnetic material magnetized by an electromagnet or the like. The magnetostrictive ring 11 is press-fitted into the shaft 10 serving as the torque detection shaft of the present invention, and rotates together with the shaft 10. One end of the shaft 10 is connected to the transmission in the first power transmission device 3, and the other end is connected to the propeller shaft in the second power transmission device 4. Then, the rotation of the transmission is transmitted to the propeller shaft and rotates with them. The rotation speed of the shaft 10 is the same as the rotation speed of the propeller shaft.

  A magnetic sensor 12 is disposed in the vicinity of the magnetostrictive ring 11. The magnetic sensor 12 measures a magnetic field generated by the rotation of the magnetostrictive ring 11 that rotates together with the shaft 10, converts the measured magnetic field into an electric signal, and outputs the electric signal to the control device 13. In the control device 13, a change in the magnetic field generated in the magnetostrictive ring 11 is detected based on the change over time of the electrical signal output from the magnetic sensor 12.

  Further, a rotation angle sensor (not shown) is attached to the shaft 10. The rotation angle sensor measures the rotation angle of the shaft 10, converts the measured rotation angle of the shaft 10 into an electrical signal, and outputs it to the control device 13. The rotation angle sensor can also detect the rotation speed of the shaft 10, and the rotation angle sensor also functions as a rotation speed sensor.

  In the control device 13, the magnetostrictive ring is based on the electrical signal (magnetic field signal) related to the magnetic field output from the magnetic sensor 12 and the electrical signal (rotational speed signal) related to the rotational angle and rotational speed of the shaft 10 output from the rotational angle sensor. 11 is obtained, and the regular unevenness component is extracted. Then, the regular unevenness component is removed from the torque component detected from the magnetic field of the magnetostrictive ring 11, and the detected torque is corrected. In correcting this detected torque, there are a plurality of methods for extracting regular unevenness components, which will be described later.

  The torque sensor 1 is intended to measure engine torque, but there are various disturbances in the torque detected by the torque sensor 1. Here, the torque component output from the torque sensor 1 will be described with further reference to FIG.

  As a torque component generated from the power generation source 2, there are an output fluctuation component C2 due to an explosion, a pumping loss, and the like, in addition to an engine output component C1 which is periodically generated. On the other hand, components from the traveling device 5 include an external load component C3 such as a road load and a load component C4 such as an auxiliary machine composed of a loss due to friction. The load component C4 of this auxiliary machine depends on the rotation speed of each auxiliary machine.

  These torque components are input as detection components by the torque sensor 1. In the torque sensor 1, these detection components are detected by the magnetic sensor 12, converted into electrical signals, and output to the control device 13. At this time, in the torque sensor 1, regular unevenness (regular unevenness) occurs due to uneven magnetization in the magnetostrictive ring 11 and nonuniformity of residual stress generated when the magnetostrictive ring 11 is pressed into the shaft 10. The regular unevenness component C <b> 5 resulting from this regular unevenness is detected by the magnetic sensor 12 and output to the control device 13. The regular unevenness component C5 is periodically generated with a period obtained by multiplying the rotation of the torque sensor 1 by an integer.

  In this way, each component detected by the torque sensor 1 is output to the control device 13. Each of these components appears as shown in FIG. 3 when subjected to an FFT analysis on a trial basis. The control device 13 takes out a component corresponding to the regular unevenness component C5 out of these components, makes it correspond to the rotation speed and rotation angle output from a rotation angle sensor (not shown), and corrects the output for each rotation. It is.

  Next, a method for extracting a regular unevenness component from the torque components detected by the torque sensor 1 will be specifically described. FIG. 4 is a block diagram illustrating the flow of an electrical signal when correcting the detected torque according to the present embodiment.

  As shown in FIG. 4, the torque sensor 1 detects each torque component including the engine torque and outputs it to the control device 13 as shown in FIG. 3. On the other hand, the rotation angle sensor 20 detects the rotation angle of the shaft 10 in the torque sensor 1 and outputs it to the control device 13. The control device 13 calculates the rotation speed of the shaft 10 from the rotation angle of the shaft 10.

  The control device 13 is provided with a 1st to Nth order resonance circuit 21. The resonance circuit 21 is provided with a variable resistor and a variable capacitor. By controlling these, the resonance frequency can be controlled. The resonance circuit 21 is calculated from the magnetic field detected by the magnetic sensor 12, that is, the magnetic field signal obtained by converting the torque component detected by the torque sensor 1 into an electrical signal and the rotation angle of the shaft 10 detected by the rotation angle sensor 20. A rotation speed signal obtained by converting the rotation speed of the shaft 10 into an electrical signal is output.

  The resonance circuit 21 controls the variable resistor and the variable capacitor, sets the resonance frequency to be the same as the rotation speed of the shaft 10, and filters the magnetic field signal. Regular unevenness appears in synchronization with the rotational speed of the shaft 10 due to its nature. For this reason, by applying a filter at the same resonance frequency as the rotational speed of the shaft 10, it is possible to detect a position where regular unevenness in the magnetic field signal occurs.

  Thus, when the position where the regular unevenness is generated is detected, the regular unevenness component can be extracted by corresponding to the angle detected by the rotation angle sensor. Then, regular irregularity components are removed from the separately detected engine torque to correct the torque. The resonance frequency can be set to be the same as the rotation speed of the shaft 10 or an integer multiple of the rotation speed of the shaft 10.

  As described above, according to the detected torque correction method according to the present embodiment, even when the zero point cannot be grasped, the regular unevenness component that occurs regularly can be removed. Therefore, it is possible to reliably correct errors due to regular unevenness. In the above embodiment, the resonance frequency of the resonance circuit 21 is variable, and the resonance frequency is controlled to be an integer N times the rotational speed f of the shaft 10 in the torque sensor 1. On the other hand, when the resonance frequency is set to a predetermined value, for example, a value obtained by multiplying the rotation speed f of the shaft 10 by a predetermined integer N, and the rotation speed of the shaft 10 changes to become the rotation speed f. Further, it is possible to adopt a mode in which regular unevenness components are extracted.

  Next, a second embodiment of the present invention will be described. The present embodiment is different from the first embodiment in the method of extracting the regular unevenness component, and is the same as the first embodiment in other points. Hereinafter, a method for extracting the regular unevenness component will be mainly described. In the present embodiment, regular unevenness components are extracted and corrected by a periodic average of sensor outputs.

  The regular unevenness component appears depending on the rotation angle of the shaft 10. For this reason, if the sensor output corresponding to the rotation angle of the shaft 10 is detected and added for each rotation angle of the shaft 10 while the shaft 10 rotates a plurality of times, the regular unevenness component is amplified. On the other hand, disturbances other than regular unevenness appear randomly regardless of the rotation angle of the shaft 10. Therefore, when the sensor output is added for each rotation angle of the shaft 10, other disturbances are canceled out.

  Therefore, the regular unevenness component can be extracted by detecting the sensor output of the shaft 10 and using the average value obtained by adding each rotation angle of the shaft 10. At this time, when detecting the sensor output, if the number of rotations of the shaft 10 is increased, the regular unevenness component can be extracted with higher accuracy. However, if the number of rotations of the shaft 10 is increased too much, the calculation takes time. Here, for example, an average of sensor outputs when the shaft 10 rotates 28 times is obtained.

  The control device 13 outputs a detected torque signal detected by the torque sensor 1 and a rotation angle signal of the shaft 10 output from the rotation angle sensor. The control device 13 draws the output waveform of the torque sensor 1 corresponding to the rotation angle of the torque sensor from these detected torque signal and rotation angle signal.

  FIG. 5 is a graph showing an example of the relationship between the torque component output from the torque sensor 1 and the rotation angle of the torque sensor 1 (the rotation angle of the shaft 10). The rotation angle of the torque sensor 1 here means the rotation angle of the shaft 10. FIG. 5 shows an average waveform W3 of 28 rotations obtained by measuring 28 rotations of the torque sensor output waveform W1, the regular unevenness component waveform W2, and the torque sensor output waveform W1, and taking the average thereof.

  As shown in FIG. 5, the output waveform W1 indicating the change in the magnetic field detected by the magnetic sensor 12 of the torque sensor 1 and output from the torque sensor 1 is an irregular waveform. The torque sensor output waveform W1 is continuously detected while the torque sensor 1 rotates 28 times. Thus, if the output waveform of the torque sensor 1 is continuously detected while the torque sensor 1 rotates 28 times, the waveform of the magnetic field change at each rotation of the torque sensor 1 is averaged to extract a regular unevenness component. Therefore, k (θ) is obtained by the following equations (1) and (2), and an average waveform W3 obtained by averaging the waveforms of the respective rotations is obtained from the k (θ).

トルクセンサ１の出力のうち、規則的ムラ成分については、トルクセンサ１の回転と同期した周期で周期的に現れ、他の成分とは出現周波数が異なっている。このため、トルクセンサ１が回転する周期ごとに出力波形を加算していくことにより、規則的ムラ成分は強められ、他の成分は弱められることになる。したがって、上記（１）式および（２）式によって規則的ムラ成分ｋ（θ）を求め、図５に示すように、規則的ムラ成分波形Ｗ２を求めることにより、規則的ムラ成分を取り出すことができる。

Of the output of the torque sensor 1, the regular unevenness component periodically appears at a period synchronized with the rotation of the torque sensor 1, and the appearance frequency is different from other components. For this reason, by adding an output waveform for every period in which the torque sensor 1 rotates, the regular unevenness component is strengthened and other components are weakened. Therefore, the regular unevenness component k (θ) is obtained by the above equations (1) and (2), and the regular unevenness component waveform W2 is obtained as shown in FIG. it can.

  Here, while the torque sensor 1 continues to rotate 28 times, the output waveform of the torque sensor 1 is continuously detected. However, the number of rotations of the torque sensor 1 is not particularly determined, and any number of rotations can be made as long as it is a plurality of times. Good.

  Thereafter, the detected torque can be corrected by removing the regular unevenness component in the same manner as in the first embodiment. In this manner, the detected torque correction method according to the present embodiment can correct errors due to regular unevenness even when the zero point cannot be grasped.

  Next, a third embodiment of the present invention will be described. The third embodiment is performed in the same procedure as the second embodiment, but differs in the point of taking out the regular unevenness component.

  In the second embodiment, the waveform of the magnetic field change for each rotation of the torque sensor 1 is averaged. However, when a torque fluctuation having a cycle corresponding to an integral multiple of the rotation speed of the torque sensor 1 occurs, this torque fluctuation is generated. It is conceivable that the regular unevenness component cannot be accurately detected due to the influence of the above. For example, if the gear ratio of the transmission in the first power transmission device 3 is set to 6: 1 and the output shaft of the engine rotates at a speed six times that of the shaft 10 of the torque sensor 1, torque fluctuations caused by the engine Occurs at a rate 6 times the regular unevenness component.

  In this case, as shown in FIG. 6, the waveform of the magnetic field change for each rotation of the torque sensor 1 is averaged from the output of the torque sensor in the same procedure as in the second embodiment, and the average of 28 rotations is taken. However, it is impossible to create a waveform that represents a regular unevenness component.

  In order to eliminate the influence of torque fluctuations (hereinafter referred to as “synchronous torque fluctuations”) that appear in synchronization with the rotational speed of the torque sensor 1 instead of such regular unevenness components, synchronous torque fluctuations appear in the present embodiment. When the rotational speed is other than the rotational speed, the regular unevenness component is extracted. Specifically, if the output shaft of the engine is rotating at a speed six times that of the shaft 10, the output of the torque sensor 1 for the first to fifth rotations, the seventh to eleventh rotations,. By detecting this, an accurate regular unevenness component can be taken out.

  As described above, the synchronous torque fluctuation component often has a known frequency such as engine rotation. Therefore, an accurate regular unevenness component can be extracted by averaging the detected torque of the torque sensor 1 at a portion other than the portion where the synchronous torque fluctuation component appears.

  Alternatively, there is a method of removing the synchronous torque fluctuation component first. FIG. 7 is a graph showing the detected torque component at this time. Now, it is known that the period of the synchronous torque fluctuation component is a frequency corresponding to six times the rotational speed of the torque sensor 1. For this reason, this synchronous torque fluctuation component is first extracted by the same procedure as in the second embodiment. The extracted synchronous torque fluctuation component is subtracted from the detected torque of the torque sensor 1. Then, the regular unevenness component can be taken out again by the same procedure as in the second embodiment.

  Furthermore, it can also be set as the aspect which removes a synchronous torque fluctuation component similarly to said 1st embodiment. In this case, as shown in FIG. 8, the control device 13 is provided with an Nth-order first resonance circuit 31 and a 1st to (N−1) th-order second resonance circuit 32. Among these, the resonance frequency of the first resonance circuit 31 is set to N times, for example, 6 times the rotation speed of the torque sensor 1, and the resonance frequency of the second resonance circuit 32 is the same as the rotation speed of the torque sensor 1. Is set. Further, the rotation angle signal from the rotation angle sensor 20 is output to the first resonance circuit 31 and the second resonance circuit 32, respectively.

  A magnetic field signal obtained by converting the magnetic field detected by the magnetic sensor 12 of the torque sensor 1 into an electrical signal is output from the torque sensor 1 to the first resonance circuit 31 and the second resonance circuit 32, and the rotation angle sensor 20 outputs a rotation angle. Is output as an electrical signal. In addition, an electrical signal corresponding to the torque component extracted by the first resonance circuit 31 is output to the second resonance circuit 32.

  In the torque sensor 1, the synchronous torque fluctuation component is extracted, converted into an electrical signal, and output to the second resonance circuit 32 in the same manner as in the first embodiment. In the second resonance circuit 32, the torque fluctuation component that appears with the rotation of the shaft 10 is taken out in the same manner as in the first embodiment. This torque fluctuation component includes a synchronous torque fluctuation component in addition to the regular unevenness component. Therefore, the second resonance circuit 32 subtracts the synchronous torque fluctuation component output from the first resonance circuit 31 from the extracted torque fluctuation component. Thus, the regular unevenness component can be taken out.

  Further, in the second embodiment, when the regular unevenness component is calculated, the frequency of the regular unevenness component and the rotational speed of the shaft 10 of the torque sensor 1 usually coincide with each other. However, there are cases in which both are shifted and do not match. In this case, it is considered that the regular unevenness component cannot be accurately extracted. Therefore, if the frequency of the regular unevenness component and the rotational speed of the shaft 10 are deviated, the regular unevenness component cannot be accurately extracted, and the extracted regular unevenness component is ignored and torque correction is performed. It can be set as the aspect which cancels.

  Furthermore, it is conceivable that the regular unevenness component is learned for each rotation of the torque sensor 1 and the regular unevenness component is acquired qualitatively. As such regular unevenness component is learned, the regular unevenness component extracted during one rotation of the torque sensor 1 approximates the learned regular unevenness component. However, the extracted regular unevenness component may be greatly deviated from the learned regular unevenness component. At this time, it is considered that the regular unevenness component has not been accurately extracted. Therefore, after learning the regular unevenness component, a predetermined threshold is set for whether or not the regular unevenness component that has been normally extracted is taken out of the learned regular unevenness component. If the regular unevenness component exceeds the threshold value, it can be determined that there is an abnormality in detection of the regular unevenness component, and torque correction can be stopped.

  Subsequently, a fourth embodiment of the present invention will be described. In the first to third embodiments, the rotation angle sensor that functions as the rotation speed sensor that detects the rotation of the torque sensor 1 is provided. However, in this embodiment, the rotation speed sensor is not provided. However, usually, an engine output shaft or the like is provided with a rotational speed sensor for measuring the rotational speed of the engine. In this embodiment, this rotational speed sensor is used.

  As in the first embodiment, the torque sensor 1 is provided between the first power transmission device 3 and the second power transmission device 4 as shown in FIG. Now, an engine output shaft (hereinafter referred to as “engine output shaft”) such as a crankshaft in the power generation source 2 is provided with a rotation speed sensor. This engine output shaft corresponds to the connecting rotary shaft of the present invention. In addition, the gear ratio of the transmission in the first power transmission device 3 is variable and is set to be a predetermined known gear ratio without slipping. Therefore, the engine output shaft is configured to rotate at a predetermined ratio with respect to the shaft 10 of the torque sensor 1.

  Here, for example, it is assumed that the pulse of the rotational speed sensor is 4, and the gear ratio between the engine output shaft and the shaft 10 of the torque sensor 1 is 4. In this case, the relationship between the rotation angle of the torque sensor 1 and the number of pulses of the rotation speed sensor is as shown in FIG. In FIG. 9A, the number of rotations of the torque sensor 1 corresponding to the rotation angle of the torque sensor 1 is shown on the outside, and the number of rotations of the rotation number sensor with respect to the rotation angle of the torque sensor 1 is shown on the inside. Further, the torque sensor and the rotation speed sensor rotate counterclockwise.

  As shown in FIG. 9A, when the torque sensor 1 rotates 90 degrees and rotates 1/4, the rotational speed sensor rotates once. Further, when the torque sensor 1 rotates 180 degrees and rotates 2/4, the rotational speed sensor rotates twice. Thus, since the rotation speed sensor rotates 4 times while the torque sensor 1 rotates once, the rotation speed of the torque sensor 1 can be detected from these relationships. Thereafter, the regular unevenness component can be taken out and the detected torque can be corrected in the same manner as the procedure shown in the first embodiment or the second embodiment.

  Thus, in this embodiment, it is not necessary to provide a rotation speed sensor for detecting the rotation speed of the torque sensor 1. Therefore, it can contribute to reducing the number of parts accordingly.

  By the way, when it is going to detect the rotation speed of the torque sensor 1 from the rotation speed sensor of an engine output shaft in this way, for example, the connection between the engine output shaft and the shaft 10 of the torque sensor 1 is disconnected once by a clutch or the like, and then again. May be connected. In this case, since the rotation between the rotation speed sensor and the torque sensor 1 is shifted, for example, even if there is a shift of several pulses, the shift cannot be detected.

  Therefore, in this case, the detected torques of the torque sensors 1 before and after disconnecting the clutch are compared. FIG. 9B is a graph showing regular irregularities calculated before and after the clutch is disengaged. As shown in FIG. 9B, the waveforms indicating regular unevenness before and after the clutch is disengaged have substantially the same shape, and their angles are slightly shifted. This amount of deviation is considered to correspond to the deviation between the pulse of the rotational speed sensor and the pulse of the torque sensor 1. Therefore, by correcting the angle by this amount of deviation, the deviation of the pulse when the clutch is disengaged and then reconnected can be corrected.

  Subsequently, a fifth embodiment of the present invention will be described. In the present embodiment, as in the fourth embodiment, the rotational speed of the torque sensor is obtained using the rotational speed sensor provided on the engine output shaft. In the present embodiment, a so-called auto-match commission is used as the first power transmission device 3. In the automatic transmission, the engine output shaft and the shaft 10 of the torque sensor 1 are connected in a slipping state by a fluid coupling formed of a torque converter.

  In the present embodiment, the rotational speed of the torque sensor 1 is obtained by a rotational speed sensor provided on the engine output shaft. However, since the engine and the torque sensor 1 are connected via an automatic transmission, Cannot be calculated. In this embodiment, the ratio of the approximate slip (rotation rate change state) in the automatic mission is determined by the nature of the torque converter, and is, for example, 0 to 20%.

  Therefore, the approximate rotational speed that is the approximate rotational speed of the torque sensor 1 is determined from the slip ratio. Specifically, for example, when the rotational speed detected by the rotational speed sensor is 4000 rpm, the rotational speed corresponding to the slip is subtracted, and the rotational speed (approximately rotational speed) of the torque sensor 1 is 3200 rpm to 4000 rpm. . The result of spectrum analysis is determined within the range of the approximate rotational speed.

  For example, as shown in FIG. 10, the components within the approximate rotational speed range X are extracted from the torque components detected by the torque sensor 1. After removing components TE1 and TE2 such as engine fluctuations within the range X, the largest component TP is detected. This component TP is estimated to be a component of regular rotation unevenness. Since the regular unevenness appears in synchronization with the rotation of the torque sensor 1, the frequency at which the component estimated to be regular rotational unevenness is determined as the rotational speed of the torque sensor 1.

  If the rotational speed of the torque sensor 1 is thus determined and determined, then regular unevenness components can be extracted in the same manner as in the first to third embodiments. As described above, in the present embodiment, even when the engine and the torque sensor are connected via a joint with a slip as in an automatic transmission, the rotational speed of the torque sensor is estimated from the rotational speed of the output shaft of the engine. The regular unevenness in the torque sensor can be taken out.

  Further, even in such a method, if the regular unevenness itself is small, the regular unevenness component becomes small and the regular unevenness cannot be detected, and it is conceivable that the rotational speed is not estimated. Assuming such a case, the shaft 10 or the magnetostrictive ring 11 in the torque sensor 1 may be formed with irregularities that become uneven portions. When forming irregularities on the shaft 10, as shown in FIG. 11 (a), one projection 10A may be formed. As shown in FIG. 11 (b), a plurality of, for example, eight protrusions are formed at equal intervals. It is good also as an aspect which forms protrusion 10B-10I. Of course, other modes can be adopted.

  In this way, by forming protrusions that generate regular unevenness, the rotational speed of the torque sensor can be detected without providing a rotational speed sensor that detects the rotational speed of the torque sensor.

It is a block diagram for demonstrating the transmission state of the torque in the vehicle provided with the magnetostrictive torque sensor which concerns on this invention. It is a principal part perspective view of a torque sensor. It is a block diagram which shows the flow of a torque sensor output. It is a block diagram explaining the flow of an electric signal at the time of correcting detection torque. It is a graph which shows an example of the relationship between the torque component output from the torque sensor, and the rotation angle of a torque sensor. It is a graph which shows the change for every rotation angles, such as a torque sensor output. It is a graph which shows the change for every rotation angles, such as a torque sensor output. It is a block diagram explaining the flow of an electric signal at the time of correcting detection torque. (A) is a figure which shows the relationship of the pulse number of the rotation speed sensor with respect to the rotation angle of a torque sensor, (b) is a graph which shows the relationship between detected torque and the rotation angle of a torque sensor. It is a graph which shows the relationship between a detection torque and the frequency of a torque sensor. (A) is a figure which shows the shaft which provided the processus | protrusion in order to provide regular unevenness, (b) is a figure which shows the shaft which provided the several processus | protrusion in order to provide regular unevenness.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Torque sensor, 2 ... Power generation source, 3 ... 1st power transmission device, 4 ... 2nd power transmission device, 5 ... Traveling device, 10 ... Shaft, 10A-10I ... Projection, 11 ... Magnetostriction ring, 12 ... Magnetism Sensor, 13 ... Control device, 20 ... Rotation angle sensor, 21 ... Resonance circuit, 31 ... First resonance circuit, 32 ... Second resonance circuit, C1 ... Output component, C2 ... Output fluctuation component, C3 ... Load component, C4 ... Load component, C5 ... regular unevenness component, W1 ... torque sensor output waveform, W2 ... regular unevenness component waveform, W3 ... average waveform.

Claims (10)

A magnetic sensor generates a magnetic field generated by a magnetostriction ring attached to a torque detection shaft including a shaft that transmits engine rotation in a vehicle, and detects a torque detected by a magnetostrictive torque sensor that detects torque of the torque detection shaft. A detection torque correction method of a magnetostrictive torque sensor to be corrected,
Detecting the rotational speed of the torque detection shaft;
Converting the magnetic field detected by the magnetic sensor into a magnetic field signal, and converting the rotational speed of the torque detection shaft into a rotational speed signal;
The magnetic field signal and the rotation speed signal are supplied to a resonance circuit, a regular unevenness component of a magnetic field change detected by the magnetic sensor is extracted by the resonance circuit, the regular unevenness component is removed, and the magnetostrictive type A method for correcting a detected torque of a magnetostrictive torque sensor, wherein the detected torque detected by the torque sensor is corrected.   The method for correcting a detected torque of a magnetostrictive torque sensor according to claim 1, wherein a resonance frequency in the resonance circuit is set to an integral multiple of the number of rotations of the torque detection shaft. The resonance frequency in the resonance circuit is set to a predetermined value,
The method for correcting a detected torque of a magnetostrictive torque sensor according to claim 1, wherein the magnetic sensor detects a magnetic field when the resonance frequency is an integral multiple of the number of rotations of the torque detection shaft. A magnetic sensor generates a magnetic field generated by a magnetostriction ring attached to a torque detection shaft including a shaft that transmits engine rotation in a vehicle, and detects a torque detected by a magnetostrictive torque sensor that detects torque of the torque detection shaft. A detection torque correction method of a magnetostrictive torque sensor to be corrected,
Detecting the rotational speed of the torque detection shaft;
While the torque detection shaft rotates a plurality of times, the magnetic field detected by the magnetic sensor is converted into a magnetic field signal, and the rotation speed is converted into a rotation speed signal.
The magnetic field change waveform detected for each rotation of the torque detection shaft detected by the magnetic sensor is averaged to extract the regular unevenness component, the regular unevenness component is removed, and the magnetostrictive torque sensor is detected. A method for correcting a detected torque of a magnetostrictive torque sensor, wherein the detected torque is corrected. Comparing the rotation speed of the torque detection shaft with the frequency of the magnetic field change detected by the magnetic sensor;
The magnetostriction according to any one of claims 1 to 4, wherein torque correction is stopped when a rotational speed of the torque detection shaft and a frequency of a magnetic field change detected by the magnetic sensor are deviated. Torque detection method of the type torque sensor. A regular unevenness component is calculated for each rotation of the magnetic sensor, and the regular unevenness component is learned based on the regular unevenness component for each rotation of the calculated magnetic sensor ,
The torque correction is stopped when it is determined that the calculated regular unevenness component is abnormal because the calculated regular unevenness component exceeds a predetermined threshold value with respect to the learned regular unevenness component. The method for correcting the detected torque of the magnetostrictive torque sensor according to claim 1. Detecting the number of rotations of a connecting rotating shaft connected to rotate at a predetermined ratio with respect to the torque detecting shaft;
The detected torque of the magnetostrictive torque sensor according to any one of claims 1 to 6, wherein the rotational speed of the torque detection shaft is calculated from the rotational speed of the connection rotational shaft and the predetermined ratio. Correction method. Storing a waveform pattern indicating a magnetic field change detected by the magnetic sensor;
The waveform pattern indicating the stored magnetic field change is compared with the newly detected waveform pattern indicating the magnetic field change, and the waveform shift indicating the newly detected magnetic field change is corrected. The method for correcting the detected torque of the magnetostrictive torque sensor. Detecting the number of rotations of a connecting rotating shaft connected to rotate in a predetermined rotation rate change state with respect to the torque detecting shaft;
Subtracting the number of rotations corresponding to the predetermined rotation rate change state from the number of rotations of the connecting rotation shaft to obtain the approximate number of rotations of the torque detection shaft,
Removing a non-uniformity component estimated to be other than the regular non-uniformity component within a predetermined range around the approximate rotational speed, and taking out the component presumed to be the regular non-uniformity component;
The method for correcting a detected torque of a magnetostrictive torque sensor according to any one of claims 1 to 6, wherein a frequency at which a component that is estimated to be the regular unevenness component is generated is determined as a rotation speed of the torque detection shaft. .   The method for correcting a detected torque of a magnetostrictive torque sensor according to claim 9, wherein a non-uniformity generating portion is formed in the magnetostrictive torque sensor to detect the rotational speed of the torque detection shaft.

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