JP2008241589A - Torque sensor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To determine that either one of a first magnetic sensor and a second magnetic sensor is failed, without increasing the number of members and complicating the structure. <P>SOLUTION: The apparatus includes a magnetostrictive ring comprising a first region and a second region arranged adjacent to each other in an axial direction of a rotation shaft member; a first magnetic sensor 3 that detects a predetermined direction change of magnetic flux occurring the first region; a second magnetic sensor 4 that detects a predetermined direction change of magnetic flux occurring the second region; a torque detecting section 5 that detects a torque based on a difference between the detected value of the first magnetic sensor 3 and the detected value of the second magnetic sensor 4; and a failure determining section 7 that determines whether or not either one of the first magnetic sensor 3 and the second magnetic sensor 4 is failed, based on a correlating between the detected value of the first magnetic sensor 3 and the detected value of the second magnetic sensor 4. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  According to the present invention, a first region magnetized so as to form a magnetic field along one circumferential direction of the rotary shaft member and a magnetic field along the opposite side of the one circumferential direction are fixed to the rotary shaft member. According to the torque applied to the rotary shaft member, and a magnetostriction ring having at least one pair of regions arranged so that the second region magnetized to be adjacent to the axial center direction of the rotary shaft member A first magnetic sensor that detects a change in magnetic flux in a predetermined direction that occurs in the first region, and a change in magnetic flux in the predetermined direction that occurs in the second region in response to a torque applied to the rotating shaft member. And a torque detector that detects a torque applied to the rotary shaft member based on a difference between a detection value of the first magnetic sensor and a detection value of the second magnetic sensor. The present invention relates to a torque sensor device.

The torque sensor device as described above detects the magnitude of torque applied to various rotary shaft members such as a vehicle steering shaft, engine crankshaft, drive shaft, electric motor and generator input or output shaft. .
When no torque is applied to the rotating shaft member, a magnetic field is formed over the entire circumference along the circumferential direction of the rotating shaft member in each of the first region and the second region. The magnetic flux does not change in the axial direction of the rotating shaft member. When torque is applied to the rotating shaft member, the magnetostrictive ring is distorted according to the magnitude of the torque, and the change of the magnetic flux according to the magnitude of torque in a predetermined direction (for example, the axial direction of the rotating shaft member). Occurs. Since the first region and the second region form a magnetic field along the opposite side in the circumferential direction of the rotating shaft member, when torque is applied to the rotating shaft member, the first region and the second region (for example, the axis of the rotating shaft member). Direction), the magnetic flux changes on the opposite side.
Therefore, in the conventional torque sensor device, the torque detector detects the magnitude of the torque applied to the rotating shaft member based on the difference between the detection value of the first magnetic sensor and the detection value of the second magnetic sensor. (For example, refer to Patent Document 1).

  External noise arrives in a predetermined direction, for example, when a predetermined direction (for example, the axial direction of the rotating shaft member) for detecting a change in magnetic flux by the first magnetic sensor and the second magnetic sensor coincides with the flow direction of geomagnetism. There is. Therefore, in the conventional torque sensor device, the external noise in a predetermined direction is canceled by taking the difference between the detection value of the first magnetic sensor and the detection value of the second magnetic sensor. Therefore, even when external noise arrives in a predetermined direction due to geomagnetism or the like, the torque applied to the rotating shaft member can be accurately detected.

JP 2006-10669 A

  In the above-described conventional torque sensor device, even if one of the first magnetic sensor and the second magnetic sensor is out of order, if the detected value of the failed sensor is a certain value such as zero. Therefore, a difference occurs between the detection value of the first magnetic sensor and the detection value of the second magnetic sensor, and it is detected that torque based on the difference is applied to the rotating shaft member. . Therefore, it may not be possible to determine that one of the first magnetic sensor and the second magnetic sensor is out of order.

Therefore, as shown in FIG. 10, a torque sensor device in which a magnetostrictive ring 2 having a first region 2 a and a second region 2 b in which a magnetic field is formed is fixed to a rotary shaft member 1 as indicated by a white arrow in the figure. , A failure detection magnetic sensor 100 is provided for each of the first magnetic sensor 3 and the second magnetic sensor 4 to determine whether or not the first magnetic sensor 3 and the second magnetic sensor 4 are out of order. Can be considered. In FIG. 10, when torque is applied to the rotating shaft member 1, magnetic fluxes C1 and C2 are generated on the opposite sides in the axial direction X of the rotating shaft member 1 in the first region 2a and the second region 2b. Show.
The failure determination magnetic sensor 100 provided for the first magnetic sensor 3 is similar to the first magnetic sensor 3 in that a magnetic flux in a predetermined direction (for example, the axial direction X of the rotary shaft member 1) generated in the first region 2a is generated. Change is detected. The failure determination magnetic sensor 100 is provided such that the direction in which the change in magnetic flux is detected is opposite to the first magnetic sensor 3 in a predetermined direction (for example, the axial direction X of the rotary shaft member 1). .

The first magnetic sensor 3 and the failure detection magnetic sensor 100 detect the same change in magnetic flux as a change in opposite magnetic flux in a predetermined direction (for example, the axial direction X of the rotating shaft member 1). Therefore, if the first magnetic sensor 3 and the failure detection magnetic sensor 100 are normal, the sum of the detection value of the first magnetic sensor 3 and the detection value of the failure detection magnetic sensor 100 is a predetermined value (for example, “0”). It becomes. Therefore, when the sum of the detection value of the first magnetic sensor 3 and the detection value of the failure detection magnetic sensor 100 does not become a predetermined value (for example, “0”), it can be determined that the first magnetic sensor 3 has failed. .
Similarly, it can also be determined that the second magnetic sensor 4 has failed by obtaining the sum of the detection value of the second magnetic sensor 4 and the detection value of the failure detection magnetic sensor 100.
However, in this case, a failure detection magnetic sensor must be provided for each of the first magnetic sensor and the second magnetic sensor, which increases the number of parts and may lead to a complicated configuration. .

  The present invention has been made in view of the above-described problems, and the object of the present invention is to break down one of the first magnetic sensor and the second magnetic sensor without increasing the number of members and complicating the configuration. It is in the point which provides the torque sensor apparatus which can determine that it is.

  In order to achieve the above object, the torque sensor device according to the present invention is characterized in that the first region is fixed to the rotating shaft member and magnetized so as to form a magnetic field along one of the circumferential directions of the rotating shaft member. And at least one pair of regions in which a second region magnetized so as to form a magnetic field along the opposite side of one of the circumferential directions is disposed adjacent to the axial direction of the rotating shaft member. A magnetostrictive ring; a first magnetic sensor that detects a change in magnetic flux in a predetermined direction that occurs in the first region in accordance with torque applied to the rotating shaft member; and the torque in accordance with torque applied to the rotating shaft member. Based on a difference between a detection value of the second magnetic sensor and a detection value of the second magnetic sensor that detects a change in magnetic flux in the predetermined direction that occurs in the second region, the rotating shaft member Detects torque applied to A torque sensor device comprising: a torque detector; and a first magnetic sensor and a second magnetic sensor based on a correlation between a detected value of the first magnetic sensor and a detected value of the second magnetic sensor. A failure determination unit that determines whether any one of the sensors has failed is provided.

That is, when torque is applied to the rotating shaft member, the magnetic flux changes on the opposite side between the first region and the second region in a predetermined direction (for example, the axial direction of the rotating shaft member). When both the sensor and the second magnetic sensor are normal, there is a relationship such that when one detection value increases, the other detection value decreases. Therefore, if the relationship is broken, it can be determined that one of the first magnetic sensor and the second magnetic sensor is broken.
Therefore, in the present invention, based on the correlation between the detection value of the first magnetic sensor and the detection value of the second magnetic sensor, whether or not one of the first magnetic sensor and the second magnetic sensor has failed is determined. By providing a failure determination unit for determining, it is determined that either one of the first magnetic sensor and the second magnetic sensor has failed.
In this way, since it is only necessary to provide a failure determination unit, it is possible to determine that either one of the first magnetic sensor or the second magnetic sensor has failed without causing an increase in the number of members and a complicated configuration. A torque sensor device that can be determined can be provided.

  In the torque sensor device according to the present invention, the failure determination unit may cause the detection value of the first magnetic sensor or the detection value of the second magnetic sensor to increase or decrease by a predetermined amount during a predetermined time. If one of the first magnetic sensor and the second magnetic sensor fails when the other does not change to the decrease side or the increase side corresponding to the predetermined amount during the predetermined time, It is preferable that the configuration is such that it is determined that the image is being performed.

That is, when both the first magnetic sensor and the second magnetic sensor are normal, for example, if the detection value of the first magnetic sensor changes to a predetermined amount increase side or a decrease side during a predetermined time, the second magnetic sensor A relationship is established in which the detection value of the sensor changes to the amount decreasing side or increasing side corresponding to the predetermined amount.
Therefore, the failure determination unit compares the change in the detection value of the first magnetic sensor and the change in the detection value of the second magnetic sensor during a predetermined time, and compares the detection value of the first magnetic sensor and the second magnetic sensor. When one of the detection values changes to the predetermined amount increase side or the decrease side, the other depends on whether the other changes to the amount decrease side or the increase side corresponding to the predetermined amount. It is determined whether any one of the magnetic sensors has failed. Accordingly, it can be accurately determined that either one of the first magnetic sensor and the second magnetic sensor is out of order.

  In the torque sensor device according to the present invention, the detection value of the first magnetic sensor and the second magnetic sensor are set such that the sum of the detection value of the first magnetic sensor and the detection value of the second magnetic sensor becomes a predetermined value. An adjustment state storage unit that stores an adjustment state when at least one of the detection values of the sensor is adjusted is provided, and the failure determination unit is configured to have the adjustment state stored in the adjustment state storage unit. When the sum of the detection value of the first magnetic sensor and the detection value of the second magnetic sensor does not become the predetermined value when at least one of the detection value of the magnetic sensor and the detection value of the second magnetic sensor is adjusted. It is preferable that the configuration is such that any one of the first magnetic sensor and the second magnetic sensor is determined to be faulty.

That is, when adjusting at least one of the detection value of the first magnetic sensor and the detection value of the second magnetic sensor so that the sum of the detection value of the first magnetic sensor and the detection value of the second magnetic sensor becomes a predetermined value, When both the first magnetic sensor and the second magnetic sensor are normal, there is a relationship that the sum of the detection value of the first magnetic sensor and the detection value of the second magnetic sensor becomes a predetermined value.
Therefore, the failure determination unit adjusts at least one of the detection value of the first magnetic sensor and the detection value of the second magnetic sensor so that the adjustment state stored in the adjustment state storage unit is obtained. By comparing the sum of the detected value and the detected value of the second magnetic sensor with the predetermined value, it is determined whether one of the first magnetic sensor and the second magnetic sensor has failed. Accordingly, it can be accurately determined that either one of the first magnetic sensor and the second magnetic sensor is out of order.

An embodiment of a torque sensor device according to the present invention will be described with reference to the drawings.
[First Embodiment]
As shown in FIGS. 1 and 2, the torque sensor device is fixed to the rotary shaft member 1 and includes a first region 2a and a second region 2b. The magnetostrictive ring 2 includes a predetermined direction (first direction 2a). A first magnetic sensor 3 that detects a change in magnetic flux in the axial direction X) of the rotary shaft member 1 and a change in magnetic flux in a predetermined direction (axial direction X of the rotary shaft member 1) that occurs in the second region 2b. A second magnetic sensor 4 is provided.

As the rotating shaft member 1, various rotating shaft members such as a steering shaft of a vehicle, an engine crankshaft, a drive shaft, an electric motor, and an input or output shaft of a generator can be used.
The first magnetic sensor 3 and the second magnetic sensor 4 are sensors having the same characteristics. For example, a sensor such as a Hall element, Hall IC, semiconductor MR, MI element, or fluxgate sensor can be used.

The magnetostrictive ring 2 is magnetized so that the first region 2a forms a magnetic field along one of the circumferential directions of the rotating shaft member 1, as indicated by the white arrow in FIG. The rotating member 1 is magnetized so as to form a magnetic field along the opposite side of the circumferential direction. The first region 2 a and the second region 2 b are arranged so as to be adjacent to the axial direction X of the rotary shaft member 1.
The first magnetic sensor 3 and the second magnetic sensor 4 are arranged around the magnetostrictive ring 2 by a support member not shown. In the axial direction X of the rotating shaft member 1, the first magnetic sensor 3 is disposed at a position corresponding to the first region 2a, and the second magnetic sensor 4 is disposed at a position corresponding to the second region 2b. .

As shown in FIG. 1, when no torque is applied to the rotating shaft member 1, a magnetic field is applied over the entire circumference along the circumferential direction of the rotating shaft member 1 in each of the first region 2 a and the second region 2 b. Therefore, no magnetic flux is generated in the axial direction X of the rotary shaft member 1. As shown in FIG. 2, when torque is applied to the rotating shaft member 1, the magnetostrictive ring 2 is distorted according to the magnitude of the torque, and as shown by the arrows in FIG. Magnetic flux is generated in the axial direction X. Since the first region 2 a and the second region 2 b form a magnetic field along the opposite side in the circumferential direction of the rotating shaft member 1, the magnetic fluxes C 1 and C 2 are on the opposite side in the axial direction X of the rotating shaft member 1. Arise.
The first magnetic sensor 3 and the second magnetic sensor 4 detect a change in magnetic flux in the axial direction X of the rotating shaft member 1 with the right side in FIG. 2 being positive and the left side being negative. In the configuration shown in FIG. 2, the first magnetic sensor 3 detects a negative magnetic flux C1, and the second magnetic sensor 4 detects a positive magnetic flux C2.

As shown in FIG. 3, the torque sensor device includes a detection value of the first magnetic sensor 3 (hereinafter referred to as a first output value) and a detection value of the second magnetic sensor 4 (hereinafter referred to as a second output value). Based on the difference between them, a torque detector 5 for detecting the torque applied to the rotary shaft member 1 is provided. The first output value of the first magnetic sensor 3 and the second output value of the second magnetic sensor 4 are input to the torque detection unit 5 after the output value is adjusted by the output adjustment unit 6.
The torque detector 5 obtains a difference between the first output value of the first magnetic sensor 3 and the second output value of the second magnetic sensor 4 input from the output adjuster 6, and shows the difference between the obtained output values. 4 is used to determine the magnitude of the torque applied to the rotating shaft member 1. FIG. 4 shows a predetermined relationship between the difference between the output values and the torque, and the torque detector 5 outputs this relationship as shown in FIG.

The adjustment of the output value in the output adjustment unit 6 will be described.
FIG. 5 illustrates the first output value A of the first magnetic sensor 3 and the second output value B of the second magnetic sensor 4 at each torque magnitude. In the case shown in FIG. 5, when the torque is “0”, the difference between the first output value A and the second output value B is not “0”. Since the torque is obtained from the difference between the first output value of the first magnetic sensor 3 and the second output value of the second magnetic sensor 4, when the torque is "0", the first output value and the second output value The difference needs to be “0”.
Further, in the case shown in FIG. 5, the magnitude of the slope of the first output value A is different from the magnitude of the slope of the second output value B, and the sensitivity of the first magnetic sensor 3 and the sensitivity of the second magnetic sensor 4 are different. ing. The sensitivity of the first magnetic sensor 3 and the sensitivity of the second magnetic sensor 4 are preferably the same.

Therefore, as shown in FIG. 6, the output adjustment unit 6 performs zero point adjustment and sensitivity adjustment, adjusts the first output value A to the adjusted first output value A1, and adjusts the second output value B to the second output value. B1 is adjusted so that when the torque is “0”, the difference between the adjusted first output value A1 and the adjusted second output value B1 becomes “0”, and the slope of the adjusted first output value A1 And the slope of the adjusted second output value B1 are the same.
In this way, the output adjustment unit 6 outputs the adjusted first output value A1 and the adjusted second output value B1 that have been adjusted to zero and sensitivity to the torque detection unit 5.

  This torque sensor device is provided with a failure determination unit 7 that determines whether any one of the first magnetic sensor 3 and the second magnetic sensor 4 has failed. Based on the correlation between the detection value of the first magnetic sensor 3 and the detection value of the second magnetic sensor 4, the failure determination unit 7 detects that one of the first magnetic sensor 3 and the second magnetic sensor 4 has failed. It is configured to determine whether or not.

As shown in FIG. 6, the failure determination unit 7 includes an adjustment first output value A <b> 1 of the first magnetic sensor 3 adjusted by the output adjustment unit 6 and an adjustment second output value B <b> 1 of the second magnetic sensor 4. Is entered. When both the first magnetic sensor 3 and the second magnetic sensor 4 are normal, the adjusted first output value A1 and the adjusted second output value B1 change on the opposite side during the predetermined time T. The amount of change corresponds.
For example, when the adjusted first output value A1 changes from a1 to a2 during the predetermined time T, the adjusted second output value B1 changes from b1 to b2 during the predetermined time T. The relationship is established.

Therefore, for example, when the adjusted first output value A1 of the first magnetic sensor 3 changes from a1 to a2 during the predetermined time T, the failure determination unit 7 determines that the second magnetic sensor 4 during the predetermined time T. When the adjusted second output value B1 does not change from b1 to b2, it is determined that one of the first magnetic sensor 3 and the second magnetic sensor 4 has failed.
That is, when one of the adjusted first output value A1 and the adjusted second output value B1 changes to a predetermined amount increase side or a decrease side during a predetermined time, the failure determination unit 7 It is configured to determine that one of the first magnetic sensor 3 and the second magnetic sensor 4 is out of order when there is no change in the amount decreasing or increasing corresponding to the predetermined amount. Yes.
The predetermined time at this time may be a time when either one of the adjusted first output value A1 and the adjusted second output value B1 changes, and may be a fixed time or change the predetermined time. At this time, when the first magnetic sensor 3 and the second magnetic sensor 4 are both normal, one of the adjusted first output value A1 and the adjusted second output value B1 changes. The other is an amount that changes with the change, and the predetermined amount and the amount corresponding to the predetermined amount need not be the same.

  As described above, the failure determination unit 7 compares the change in the adjusted first output value A1 of the first magnetic sensor 3 and the change in the adjusted second output value B1 of the second magnetic sensor 4 during the predetermined time T. It is determined whether any one of the first magnetic sensor 3 and the second magnetic sensor 4 is out of order. The failure determination unit 7 is configured to output an abnormal signal to the outside when it is determined that one of the first magnetic sensor 3 and the second magnetic sensor 4 has failed.

[Second Embodiment]
This 2nd Embodiment shows another embodiment of the failure determination part 7 in the said 1st Embodiment.
In the second embodiment, as shown in FIG. 7, the first output value A of the first magnetic sensor 3 and the second output value B of the second magnetic sensor 4 are set to the predetermined value so that the sum is a predetermined value. An adjustment state storage unit 8 that stores an adjustment state when both the output value A and the second output value B are adjusted is provided.
The adjustment state storage unit 8 adjusts both the first output value A and the second output value B so that the sum of the first output value A and the second output value B becomes a predetermined value. It is also possible to adjust one of the first output value A and the second output value B so that the sum of the first output value A and the second output value B becomes a predetermined value.

In the example shown in FIG. 5, the sum of the first output value A of the first magnetic sensor 3 and the second output value B of the second magnetic sensor 4 differs depending on the magnitude of the torque. As shown in FIG. 8, the adjustment state storage unit 8 sets the first output value A so that the first output value A and the second output value B are symmetric with respect to a positive value and a negative value about the predetermined value K. The adjusted first output value A2 and the second output value B are adjusted to the adjusted second output value B2, and the adjustment states of the first output value A and the second output value B at that time are stored. The adjustment state at this time is, for example, an adjustment amount in the magnitude direction for adjusting the first output value A to the adjusted first output value A2, and to adjust the second output value B to the adjusted second output value B2. Is the amount of adjustment in the direction of. The predetermined value K may be a constant value or changeable. Incidentally, the adjusted first output value A2 and the adjusted second output value B2 shown in FIG. 8 are the same as the adjusted first output value A1 and the adjusted second output value A2 shown in FIG. Therefore, adjusting both the first output value A and the second output value B so that the sum of the first output value A and the second output value B becomes a predetermined value means that the first output value A and the second output value B This is the same as performing the zero point adjustment and the sensitivity adjustment for each of the output values B.
The adjustment state storage unit 8 stores the adjustment state stored for the first output value A of the first magnetic sensor 3 and the first output value A, the second output value B of the second magnetic sensor 4 and the second output value B thereof. The adjustment state stored for the output value B is output to the failure determination unit 7.

When both the first magnetic sensor 3 and the second magnetic sensor 4 are normal, the first output value A is set so that the adjustment state stored in the adjustment state storage unit 8 is obtained as shown in FIG. When both the second output value B and the second output value B are adjusted, a relationship that the sum of the adjusted first output value A and the adjusted second output value B becomes a predetermined value K is established. The failure determination unit 7 adjusts both the first output value A and the second output value B so that the adjustment state stored in the adjustment state storage unit 8 is obtained, and adjusts the first output value A after adjustment and the adjustment. If the sum of the subsequent second output value B does not become the predetermined value K, it is determined that one of the first magnetic sensor 3 and the second magnetic sensor 4 has failed.
In this way, the failure determination unit 7 compares the first output value of the first magnetic sensor 3 and the output value of the second magnetic sensor 4 at a certain point in time to determine the first magnetic sensor 3 and the second magnetic sensor 4. It is determined whether any one of them is out of order.

[Another embodiment]
(1) In the first and second embodiments described above, in order to accurately detect a change in magnetic flux with the first magnetic sensor 3 and the second magnetic sensor 4, a yoke formed from a material with high magnetic permeability or external noise It is possible to provide a shield member that eliminates the influence of the above.
For example, as shown in FIG. 9, an inner yoke 9 is disposed between the first magnetic sensor 3 and the second magnetic sensor 4, and the outer side of the first magnetic sensor 3 and the outer side of the second magnetic sensor 4, respectively. An outer yoke 10 can be provided.

(2) In the first embodiment, the failure determination unit 7 uses the output adjustment unit 6 to adjust the zero point of the first output value of the first magnetic sensor 3 and the second output value of the second magnetic sensor 4, respectively. Based on the sensitivity-adjusted output value, it is determined whether one of the first magnetic sensor 3 and the second magnetic sensor 4 is out of order. Instead of this configuration, for example, the failure determination unit 7 performs only zero adjustment of the first output value of the first magnetic sensor 3 and the second output value of the second magnetic sensor 4 by the output adjustment unit 6. Based on the output value, it can also be determined whether one of the first magnetic sensor 3 and the second magnetic sensor 4 is out of order.

(3) In the above two embodiments, the adjustment state storage unit 8 can also serve as the output adjustment unit 6. That is, the adjustment state storage unit 8 causes the first output value A and the first output value so that the sum of the first output value A of the first magnetic sensor 3 and the second output value B of the second magnetic sensor 4 becomes a predetermined value. At least one of the two output values B is adjusted and the adjustment state at that time is stored, and each of the first output value A and the second output value B is subjected to zero adjustment and sensitivity adjustment to the torque detector 5. Output.

(4) In the first and second embodiments, the magnetostrictive ring 2 includes one pair of the first region 2a and the second region 2b. However, the number of the pair of regions included in the magnetostrictive ring 2 is as follows. It can be changed as appropriate. For example, one first region 2a may be sandwiched between two second regions 2b so that one first region 2a also serves as two first regions 2a.

  As described above, the present invention is based on the magnetostrictive ring including the first region and the second region, and based on the difference between the detection value of the first magnetic sensor and the detection value of the second magnetic sensor, And a torque detector for detecting the torque to be generated, and various types of which can determine whether one of the first magnetic sensor and the second magnetic sensor is out of order without increasing the number of members and complicating the configuration. Applicable to torque sensor device.

Perspective view of torque sensor device Side view of the torque sensor device in a state where torque is applied to the rotating shaft member Control block diagram of torque sensor device according to first embodiment The figure which shows the relationship between the difference of the 1st output value of a 1st magnetic sensor, and the 2nd output value of a 2nd magnetic sensor, and a torque. The figure which shows the 1st output value of a 1st magnetic sensor, and the 2nd output value of a 2nd magnetic sensor. The figure which shows the 1st output value of the 1st magnetic sensor and the 2nd output value of the 2nd magnetic sensor which carried out zero point adjustment and sensitivity adjustment by the output adjustment part. Control block diagram of torque sensor device in second embodiment The figure which shows the 1st output value of the 1st magnetic sensor and the 2nd output value of the 2nd magnetic sensor which were adjusted in the adjustment state memory | storage part. The perspective view of the torque sensor apparatus in another embodiment Side view of torque sensor device exemplified in problem to be solved by the invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rotating shaft member 2 Magnetostrictive ring 2a 1st area | region 2b 2nd area | region 3 1st magnetic sensor 4 2nd magnetic sensor 5 Torque detection part 7 Failure determination part 8 Adjustment state memory | storage part

Claims (3)

The first region fixed to the rotating shaft member and magnetized so as to form a magnetic field along one circumferential direction of the rotating shaft member and magnetized so as to form a magnetic field along the opposite side of the one circumferential direction A magnetostrictive ring provided with at least one pair of regions in which the second region is arranged so as to be adjacent to the axial center direction of the rotating shaft member;
A first magnetic sensor for detecting a change in magnetic flux in a predetermined direction generated in the first region in accordance with a torque applied to the rotating shaft member;
A second magnetic sensor for detecting a change in magnetic flux in the predetermined direction that occurs in the second region in accordance with torque applied to the rotating shaft member;
A torque sensor device provided with a torque detector that detects torque applied to the rotary shaft member based on a difference between a detection value of the first magnetic sensor and a detection value of the second magnetic sensor;
Based on the correlation between the detection value of the first magnetic sensor and the detection value of the second magnetic sensor, it is determined whether one of the first magnetic sensor and the second magnetic sensor has failed. A torque sensor device provided with a failure determination unit.   The failure determination unit is configured such that when one of the detection value of the first magnetic sensor and the detection value of the second magnetic sensor changes to a predetermined amount increasing side or decreasing side during a predetermined time, the other is the predetermined value. A configuration is adopted in which it is determined that one of the first magnetic sensor and the second magnetic sensor is out of order when the amount does not change to the decrease side or increase side corresponding to the predetermined amount during the time. The torque sensor device according to claim 1. At least one of the detection value of the first magnetic sensor and the detection value of the second magnetic sensor is adjusted so that the sum of the detection value of the first magnetic sensor and the detection value of the second magnetic sensor becomes a predetermined value. An adjustment status storage unit is provided for storing the adjustment status when
The failure determination unit adjusts at least one of the detection value of the first magnetic sensor and the detection value of the second magnetic sensor so as to be in the adjustment state stored in the adjustment state storage unit. When the sum of the detection value of the first magnetic sensor and the detection value of the second magnetic sensor does not become the predetermined value, it is determined that one of the first magnetic sensor and the second magnetic sensor is out of order. The torque sensor device according to claim 1 configured as described above.

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