JP2007163432A - Apparatus for measuring axial torque of drive shaft - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for measuring the axial torque of a drive shaft and capable of accurately measuring axial torque acting on the drive shaft, contributing to lightweight formation of the drive shaft, and estimating an action force between a road surface and tires. <P>SOLUTION: Sensor targets 4 and 5 are each provided for outer rings 2a and 3a of constant-velocity joints 2 and 3 of a drive shaft connected to a drive system of an automobile via the constant-velocity joints at both ends. Sensors 6 and 7 for detecting conditions caused by the helix angle of the drive shaft 1 are provided in such a way as to be each opposed to the sensor target 4 and 5. Output of the sensors is compared with each other at an axial torque operation part 10 to determine the axial torque of the drive shaft. The sensor 6 and 7 each opposed to the sensor target 4 and 5 each comprise a plurality of sensors. The axial torque operation part 10 determines the axial torque by comparing results of prescribed processing of output of the plurality of sensors 6 and 7 opposed to the sensor target 4 and 5 with one another. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an apparatus for measuring a shaft torque of a drive wheel axle having a role of transmitting power of an engine of an automobile to a wheel, that is, a drive shaft. As such a drive shaft, a front axle of a front wheel drive vehicle, a rear axle of a rear wheel drive vehicle, and an entire axle of an all wheel drive vehicle are applicable.

In an automobile drive shaft that employs an independent suspension type suspension, it is necessary to transmit a driving force while following the movement of the suspension. For this reason, one end of the drive shaft is connected to the differential via a constant velocity joint, and the other end is connected to an axle (axle) via the constant velocity joint. In this way, the drive shaft is incorporated in a drive system that transmits engine power to the wheels, and the engine power is finally transmitted to the wheels by the drive shaft.
In addition, electronic control technology has been introduced in all parts of recent automobiles, and wheel speed signals are used for driving control such as anti-lock brake system (ABS), traction control system (TCS), and non-slip differential (LSD). Yes. For this purpose, a pulsar ring for ABS (anti-lock brake system) control is usually provided on the outboard side (axle side) of the drive shaft, and when the gear-shaped pulsar ring rotates with the rotation of the wheel, it approaches it. Thus, a pulse having a frequency proportional to the wheel speed is generated in the electromagnetic pickup installed on the vehicle body side.

In Patent Document 1, a drive shaft of an automobile having constant velocity joints at both ends, and a pulsar ring is attached to each constant velocity joint, that is, an outer ring of each constant velocity joint on the inboard side and the outboard side. A method for measuring the shaft torque of the drive shaft, which detects the rotation signal generated by the above, and calculates the shaft torque by calculating the phase difference of the rotation signal corresponding to the twist generated in the drive shaft, is shown.
In addition, by controlling the engine output based on the obtained shaft torque signal, the generation of excessive torque is prevented, and the generation of this excessive torque prevents weight reduction by reducing the shaft diameter of the drive shaft and the constant velocity joint. It is disclosed.
JP-A-7-63628

A constant velocity joint of a drive shaft used in an automobile is required to have a strength sufficient to withstand an excessive torque generated when the automobile is suddenly started or accelerated. Therefore, the shaft diameter and joint outer diameter are large, and the weight must be heavy.
On the other hand, weight reduction of the vehicle body is very effective for improving fuel efficiency, and the drive shaft is also required to be light weight.

In order to reduce the weight, it is necessary to accurately measure the shaft torque acting on the drive shaft and control the engine output with the obtained shaft torque to prevent the generation of excessive torque, as disclosed in Patent Document 1. It is effective.
However, Patent Document 1 discloses a method for obtaining the shaft torque of the drive shaft based on the phase difference between the constant velocity joints on both sides as described above, but there is no specific description for measuring the phase difference, and it is accurate. It has been desired to establish a method for measuring the correct torque.

  Also, when traveling on a low μ (coefficient of friction) road, tire slip is likely to occur, and if the road surface-tire acting force in the tire traveling direction can be measured, this measurement data is used to control this in advance by vehicle body control. It is also possible to prevent this. Therefore, establishment of a method capable of measuring the road surface-tire acting force is also desired.

  The object of the present invention is to accurately measure the axial torque acting on the drive shaft, contribute to reducing the weight of the drive shaft, and further to estimate the acting force between the road surface and the tire. Is to provide a device.

  The shaft torque measuring device for a drive shaft according to the first invention of the present invention is provided with a sensor target on the outer ring of each constant velocity joint of the drive shaft connected to the drive system of the automobile via the constant velocity joint at both ends, Opposite each of these sensor targets, a sensor for detecting the situation caused by the torsion angle of the drive shaft is provided, and the shaft of the drive shaft is provided with an axial torque calculation unit that obtains the axial torque of the drive shaft by comparing the outputs of these sensors The torque measuring device includes a plurality of sensors arranged to face each of the sensor targets, and the shaft torque calculation unit performs a predetermined process on the outputs of the plurality of sensors arranged to face each of the sensor targets. The shaft torque is obtained by comparing the results of the above.

When torque acts on the drive shaft, the drive shaft is twisted. If a sensor target is provided on the outer ring of each constant velocity joint at both ends of the drive shaft and a sensor is provided opposite to each sensor target, the situation caused by the twist angle due to the torque is detected as the output of the sensor. be able to. The shaft torque of the drive shaft is obtained by comparing the outputs of these sensors with the shaft torque calculation unit.
In this case, a plurality of sensors are arranged opposite to each sensor target, and the shaft torque calculation unit performs a comparison on the result of performing predetermined processing on the output of each sensor. Therefore, the influence of the air gap fluctuation between the sensor target and the sensor target due to the rotational fluctuation of the sensor target and the mounting error is reduced, and the axial torque acting on the drive shaft can be accurately measured.
Further, by controlling the output of the engine based on the obtained torque signal and suppressing the generation of excessive torque, it is possible to reduce the size of the shaft of the drive shaft and the constant velocity joint, thereby contributing to weight reduction of the vehicle. This weight reduction improves the fuel efficiency of the automobile. In addition, tire slip is likely to occur when driving on low-μ roads, but the force between the road surface and the tire in the tire traveling direction can be estimated and understood from the measured axial torque, and this can be prevented in advance by vehicle body control. can do.
Moreover, optimal control is possible by using the shaft torque for travel control. For example, it can be used as a drive shaft torque signal for engine control necessary for traction control. By adding drive shaft torque control to the AT transmission, efficiency is improved and fuel efficiency is improved. Optimal torque distribution can be obtained by adding drive shaft torque control to the electronic control LSD.
Thus, according to the drive shaft axial torque measuring device of this configuration, it is possible to accurately measure the axial torque acting on the drive shaft, contribute to weight reduction of the drive shaft, and further to reduce the acting force between the road surface and the tire. Estimation is possible.

  A shaft torque measuring device for a drive shaft according to a second invention of the present invention is provided with a sensor target on the outer ring of each constant velocity joint of the drive shaft connected to the drive system of the automobile via the constant velocity joint at both ends, A sensor for detecting a rotation pulse signal generated by the rotation of each sensor target is provided opposite to each sensor target, and the phase difference of the rotation signal corresponding to the torsion generated in the drive shaft is calculated to process the shaft torque of the drive shaft. An axial torque measuring device for a drive shaft having an axial torque calculation unit for obtaining a plurality of sensors arranged facing each sensor target, wherein the shaft torque calculation unit faces each sensor target The shaft is compared by comparing the results of applying predetermined processing to the outputs of the plurality of arranged sensors. Characterized in that shall determine the torque.

According to a second invention, in the first invention, a sensor for detecting a rotation pulse signal generated by rotation of each sensor target is provided as a sensor for detecting a situation caused by a twist angle of the drive shaft.
When torque acts on the drive shaft, the drive shaft is twisted. If a sensor target is provided on the outer ring of each constant velocity joint at both ends of the drive shaft, and a sensor is provided opposite to each sensor target, the twist due to the torque causes the level of the rotation signal generated by both sensor targets. Appears as a phase difference. The shaft torque of the drive shaft is obtained by computing the phase difference of the rotation pulse signal in the shaft torque computing unit.
In this case, a plurality of sensors are arranged opposite to each sensor target, and the shaft torque calculation unit calculates the phase difference with respect to the result of performing predetermined processing on the outputs of the sensors. Since the shaft torque is calculated by comparison, the influence of the air gap between the sensor target and the sensor due to the rotational deflection of the sensor target and mounting error is reduced, and the shaft torque acting on the drive shaft is accurately determined. It can be measured and contributes to the weight reduction of the drive shaft, and further, it is possible to estimate the acting force between the road surface and the tire.
In addition, it is possible to detect shaft torque by adding another sensor target consisting of a pulsar ring to a drive shaft provided with a sensor target consisting of an ABS pulsar ring, etc. The shaft torque can be detected. Moreover, since the shaft torque can be accurately measured by increasing the number of sensors arranged facing the same sensor target, the increase in cost can be suppressed as much as possible and the accuracy of measuring the shaft torque can be reduced. Can be improved.

  In these inventions, the plurality of sensors arranged facing the sensor target may be opposed to the peripheral surface of the sensor target, or may be opposed to the end surface of the sensor target.

  In the first and second inventions, a plurality of sensors arranged to face the same sensor target may be housed in one housing. In the case of this configuration, it is possible to simplify and simplify the attachment of the sensor.

  The shaft torque measuring device for a drive shaft according to the first invention of the present invention is provided with a sensor target on the outer ring of each constant velocity joint of the drive shaft connected to the drive system of the automobile via the constant velocity joint at both ends, Opposite each of these sensor targets, a sensor for detecting the situation caused by the torsion angle of the drive shaft is provided, and the shaft of the drive shaft is provided with an axial torque calculation unit for obtaining the axial torque of the drive shaft by comparing the outputs of these sensors The torque measuring device includes a plurality of sensors arranged to face each of the sensor targets, and the shaft torque calculation unit performs a predetermined process on the outputs of the plurality of sensors arranged to face each of the sensor targets. The shaft torque is calculated by comparing the results of the A shaft torque use in accurately measuring, can contribute to a reduction in the weight of the drive shaft, further, the road surface - it is possible to estimate the force acting between the tire. In addition, by increasing the number of sensors arranged opposite to the same sensor target, it is possible to accurately measure the shaft torque, thereby improving the measurement accuracy of the shaft torque at a low cost. Can do.

  A shaft torque measuring device for a drive shaft according to a second aspect of the present invention provides a sensor target on the outer ring of each constant velocity joint of the drive shaft connected to the drive system of the vehicle via a constant velocity joint at both ends, A sensor for detecting a rotation pulse signal generated by the rotation of each sensor target is provided opposite to each sensor target, and the phase difference of the rotation signal corresponding to the torsion generated in the drive shaft is calculated to process the shaft torque of the drive shaft. An axial torque measuring device for a drive shaft having an axial torque calculation unit for obtaining a plurality of sensors arranged facing each sensor target, wherein the shaft torque calculation unit faces each sensor target The shaft is compared by comparing the results of applying predetermined processing to the outputs of the plurality of arranged sensors. Because the torque is required, the shaft torque acting on the drive shaft can be measured accurately and at a very low cost, contributing to the weight reduction of the drive shaft and the estimation of the acting force between the road surface and the tire. Become. In addition, by increasing the number of sensors arranged opposite to the same sensor target, it is possible to accurately measure the shaft torque, thereby improving the measurement accuracy of the shaft torque at a low cost. Can do.

  An embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the drive shaft 1 is connected to a drive system via constant velocity joints 2 and 3 at both ends. In the case of the illustrated embodiment, the inboard side is connected to a differential (not shown) by a tripod type slide type constant velocity joint 2, and the outboard side is an axle (not shown) by a barfield type fixed type constant velocity joint 3. Concatenated with

  The constant velocity joints 2 and 3 at both ends of the drive shaft 1 are not limited to the combinations shown in the illustrated example. For example, in the case of a front axle of a front wheel drive vehicle, that is, a front wheel axle, the front wheels are steered, so that the constant velocity joint 3 on the outboard side that is the wheel side is required to have a constant velocity with a large operating angle. In order to satisfy this requirement, a barfield type fixed joint (zeppa type fixed joint), a tripod type fixed constant velocity joint, or the like is used for the constant velocity joint 3 on the outboard side. The constant velocity joint 2 on the inboard side that is the vehicle body side is required to have an operating angle that allows the suspension to move. This operating angle is not as large as that of the wheel side constant velocity joint 3, but it is necessary to enable the change of the length of the vehicle body with the movement of the suspension. For this reason, a barfield type sliding joint, a tripod type sliding joint, a cross globe joint, or the like is used for the inboard side constant velocity joint 2. The independent suspension type drive wheel rear axle does not require a steering function and does not require a large operating angle, so a cardan joint may be used.

  A sensor target 5 for ABS (anti-lock brake system) control is attached to the outer ring 3a of the constant velocity joint 3 on the outboard side. The same type of sensor target 4 is also attached to the outer ring 2a of the constant velocity joint 2 on the inboard side. The sensor targets 4 and 5 include a gear-like pulsar ring or a magnetic encoder in which N-pole and S-pole pairs are arranged in the circumferential direction. On the vehicle body side, a plurality of sensors 6, 6 and sensors 7, 7 including electromagnetic pickups are installed at positions close to these sensor targets 4, 5.

FIGS. 2A and 2B show an example in which two sensors 6 on the inboard side and two sensors 7 on the outboard side are provided, and the sensor targets 4 and 5 are respectively pulsar rings and a magnetic encoder. Indicates. As shown in the figure, the two sensors 6 and 6 on the inboard side and the two sensors 7 and 7 on the outboard side are integral multiples of the pitch angle of the teeth or magnetic pole pairs of the sensor targets 4 and 5. They are set apart by an angle.
When the sensor targets 4 and 5 rotate, pulses having a frequency proportional to the number of rotations are generated in the inboard sensors 6 and 6 and the outboard sensors 7 and 7, respectively. Each sensor target 4, 5, corresponding inboard side sensors 6, 6 and outboard side sensors 7, 7 constitute rotation detectors 8, 9 that detect the rotation speed and rotation angle, respectively.

  Here, in FIG. 1 and FIG. 2, the sensor system is composed of the sensor targets 4 and 5 made up of gear-like pulsar rings or magnetic encoders and the sensors 6 and 7 made up of electromagnetic pickups, but any sensor target may be used. . Further, as the sensors 6 and 7, an optical sensor or another magnetic sensor may be used instead of the electromagnetic pickup.

FIG. 3 shows a conceptual configuration of this drive shaft axial torque measuring apparatus. This shaft torque measuring device includes a shaft torque calculation unit 10 and rotation detectors 8 and 9 on the inboard side and the outboard side.
The shaft torque calculation unit 10 includes a phase difference calculation processing means 11 for calculating a phase difference corresponding to the twist generated in the drive shaft 1 from the rotation pulse signals detected by the sensors 6 and 7, and the calculated phase difference. And a phase difference corresponding shaft torque calculating means 12 for determining the shaft torque.
The shaft torque of the drive shaft 1 detected by the shaft torque calculation unit 10 is used for vehicle control by the vehicle travel control device 13. The rotation pulse signals detected by the sensors 6 and 7 are used for controlling an antilock brake system (not shown).
Details of the phase difference calculation processing means 11 and the phase difference corresponding shaft torque calculation means 12 will be described together with a shaft torque measuring method described below.

A shaft torque measuring method using the shaft torque measuring device having the above configuration will be described.
The shaft torque generated in the drive system is large at the time of sudden start and acceleration of the automobile, and the drive shaft 1 has the lowest rigidity except for the clutch portion in the drive systems of the four-wheeled and two-wheeled vehicles. Therefore, the drive shaft 1 is twisted. This torsion angle is calculated based on pulse signals from sensors 6 and 7 comprising an electromagnetic pickup or the like to determine the shaft torque.

  As shown in FIG. 4, when no axial torque is generated, there is no twist at both ends of the drive shaft 1, and the pulses by the sensor targets 4 and 5 on the inboard side and the outboard side are also in phase.

  However, when the shaft torque is generated, the drive shaft 1 is twisted, so that the pulses generated by the sensor target 5 on the outboard side are delayed from the pulses generated by the sensor target 4 on the inboard side, as shown in FIG. t ′ occurs. In the figure, as the phase difference t ', the falling edge of the inboard side rotation pulse and the falling edge of the outboard side rotation pulse are shown. The phase difference t ′ may be a phase difference between rising edges of each signal.

  The torsion angle of the drive shaft 1 is obtained by t '/ t, where t is the period of the inboard side rotation pulse. However, if fluctuations in the air gap between the sensor targets 4, 5, 6, and 7 occur due to rotational fluctuations or mounting errors of the sensor targets 4, 5, the rotation pulse falls or rises, leading or delaying. The phase difference t ′ and the period t cannot be accurately detected, and an error occurs in the twist angle.

Therefore, in this embodiment, a plurality of sensors 6 and 7 for detecting the rotation of the sensor targets 4 and 5 are provided, and the average of the period t and the phase difference t ′ of the rotation signal of each sensor is obtained. As a result, a more accurate twist angle can be detected. The period t and the phase difference t ′ are the above averaged periods based on the period t and the phase difference t ′ measurement clock (not shown) provided in the phase difference calculation processing means 11 of FIG. , Phase difference and the like are calculated and calculated.
In the phase difference corresponding shaft torque calculation means 12 of FIG. 3, the shaft torque is calculated and calculated based on the period t and the phase difference t ′ obtained by the phase difference calculation processing means 11. The calculation formula for obtaining the shaft torque from the phase difference is obtained in advance by measurement, calculation or simulation. Further, the nonlinearity of the torque and torsion angle inside the constant velocity joints 2 and 3 may be corrected. This makes it possible to measure the shaft torque more accurately.

  When one of the sensor targets 4 and 5 is provided for ABS, the shaft torque can be measured only by adding one sensor target different from that for ABS. The shaft torque of the drive shaft 1 can be measured at an extremely low cost.

  In this embodiment, two sensors 6 on the inboard side and two sensors 7 on the outboard side are arranged. However, by further increasing the number of sensors 6 and 7, more accurate phase difference detection can be performed. It becomes possible.

In addition, depending on the positional relationship between the sensor target 5 and the sensor 7 on the outboard side and the positional relationship between the inboard sensor target 4 and the sensor 6, no axial torque is applied to the drive shaft 1. Even so, a phase difference may be detected.
Therefore, in order to prevent such erroneous detection, the phase difference between the rotation pulse signal on the outboard side and the rotation pulse signal on the inboard side is zero when no axial torque is applied to the drive shaft 1. It is desirable to adjust the fixed positions of the sensor targets 4 and 5 to the outer rings 2a and 3a of the constant velocity joints 2 and 3 or the phase angles of the sensors 6 and 7 so that

  In addition, when there is a phase difference between the rotation pulse signal on the outboard side and the rotation pulse signal on the inboard side when no axial torque is applied to the drive shaft 1, this value is measured in advance. You may make it correct | amend the calculation result of the phase difference at the time of axial torque measurement.

  In the example shown in FIGS. 1 and 2, the corresponding sensors 6 and 7 are opposed to the sensor targets 4 and 5 on the inboard side and the outboard side from the radial direction. As shown in the front view and the side view in A) and (B), the corresponding sensors 6 and 7 may be opposed to the sensor targets 4 and 5 in the axial direction.

  In the example shown in FIG. 1, a plurality of sensors 6 on the inboard side and a plurality of sensors 7 on the outboard side are individually arranged. However, as shown in FIG. The plurality of sensors 6 on the side may be housed in one housing 14, and the plurality of sensors 7 on the outboard side may be housed in one housing 15. As described above, by housing the plurality of sensors 6 and 7 in one housing 14 and 15, the mounting of the sensors 6 and 7 can be simplified with high accuracy.

The vehicle travel control device 13 in FIG. 3 performs engine control such as delaying the ignition timing of the engine, based on the shaft torque signal obtained as described above. By doing so, generation of excessive torque can be prevented. If the generation of excessive torque can be prevented, the shaft diameter of the drive shaft 1 and the outer diameters of the constant velocity joints 2 and 3 can be reduced. Furthermore, the slip state between the road surface and the tire can be estimated and grasped by the measured value of the shaft torque thus obtained, and can be used for traveling control.
Further, the vehicle travel control device 13 uses the shaft torque signal obtained as described above for engine control for traction control, AT transmission control, electronic control LSD, and other travel control. May be.

It is a longitudinal cross-sectional view of the drive shaft and constant velocity joint which apply the axial torque measuring device concerning one Embodiment of this invention. (A) is explanatory drawing which shows arrangement | positioning of the sensor corresponding to an example of a sensor target, (B) is explanatory drawing which shows arrangement | positioning of the sensor corresponding to the other example of a sensor target. It is a block diagram which shows the conceptual structure of an axial torque measuring device. It is a time chart of a pulse generated by rotation of a sensor target when shaft torque is not generated. 6 is a time chart of pulses generated by rotation of a sensor target when shaft torque is generated. (A) is a front view which shows the other example of arrangement | positioning of the sensor corresponding to an example of a sensor target, (B) It is the same side view. It is a longitudinal cross-sectional view of the drive shaft and constant velocity joint which apply the axial torque measuring apparatus concerning other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Drive shaft 2, 3 ... Constant velocity joint 2a, 3a ... Constant velocity joint outer ring 4, 5 ... Sensor target 6, 7 ... Sensor 10 ... Shaft torque calculating part 14, 15 ... Housing

Claims (5)

A sensor target is provided on the outer ring of each constant velocity joint of the drive shaft that is connected to the drive system of the vehicle via a constant velocity joint at both ends, and the situation caused by the twist angle of the drive shaft is opposed to each sensor target. A shaft torque measuring device for a drive shaft provided with a sensor for detecting, and having a shaft torque calculation unit for obtaining the shaft torque of the drive shaft by comparing the outputs of these sensors,
A plurality of sensors are arranged facing each sensor target, and the shaft torque calculation unit compares the results of performing predetermined processing on the outputs of the plurality of sensors arranged facing each sensor target. A shaft torque measuring device for a drive shaft, characterized in that the shaft torque is obtained. A sensor target is provided on the outer ring of each constant velocity joint of the drive shaft connected to the drive system of the vehicle via a constant velocity joint at both ends, and rotation pulses generated by the rotation of each sensor target facing these sensor targets. A shaft torque measuring device for a drive shaft provided with a sensor for detecting a signal, and having a shaft torque calculation unit for calculating a shaft torque of the drive shaft by calculating a phase difference of a rotation signal corresponding to a twist generated in the drive shaft. And
A plurality of sensors are arranged facing each sensor target, and the shaft torque calculation unit compares the results of performing predetermined processing on the outputs of the plurality of sensors arranged facing each sensor target. A shaft torque measuring device for a drive shaft, characterized in that the shaft torque is obtained.   3. The drive shaft axial torque measuring device according to claim 1, wherein the plurality of sensors arranged to face the sensor target are opposed to the peripheral surface of the sensor target.   3. The drive shaft axial torque measuring device according to claim 1, wherein the plurality of sensors arranged to face the sensor target are opposed to the end face of the sensor target.   The shaft torque measuring device for a drive shaft according to any one of claims 1 to 4, wherein a plurality of sensors arranged to face the same sensor target are housed in one housing.

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