WO2013179997A1 - Position detection device and shift position detection device - Google Patents

Abstract

[Problem] The purpose of the present invention is to provide a shift position detection device that has high versatility and is low cost. [Solution] This shift position detection device (1) has a magnet (5) that moves in a first virtual plane, a magnetic sensor (2) disposed in a second virtual plane, and a position computing unit for calculating the position of the magnet (5), and is characterized by the following: the magnetic sensor (2) comprises a fixed magnetic property layer in which magnetization is fixed, a free magnetic property layer in which magnetization changes due to an external magnetic field, and a magnetic-property-free layer positioned between the fixed magnetic property layer and the free magnetic property layer; the first virtual plane is parallel to the second virtual plane and is disposed perpendicular to the magnetizing direction of the magnet (5); the second virtual plane does not include the center of the magnetizing direction of the magnet (5), and the magnet (5) is provided at a position where the magnetic flux of the second virtual plane saturates the magnetization of the free magnetic property layer of the magnetic sensor (2); and the angle formed between the magnetic sensor (2) and the magnet (5) is detected, and the position computing unit calculates the position of the magnet (5) from the angle.

Description

Position detection device and shift position detection device

The present invention relates to a position detection device for detecting the position of a magnet moving in a plane using a magnetic sensor and a magnet, and more particularly to a shift position detection device for detecting the position of a magnet moving with a shift lever.

The automatic vehicle is provided with an automatic transmission that automatically changes the gear ratio according to the speed of the vehicle. And, in order to switch the gear combination of the automatic transmission, a shift lever device is attached.

FIG. 21 illustrates a perspective view of the shift lever device 600 disclosed in Patent Document 1. As shown in FIG. FIG. 22 illustrates a shift position detection device 601 incorporated in the shift lever device 600 disclosed in Patent Document 1.

As shown in FIG. 21, the shift lever device 600 is provided with a box-shaped case 607, which is assembled to the vehicle body. A substantially rod-shaped shift lever 606 is attached to the case 607 so as to be movable with respect to the case 607 along the vehicle traveling direction and the vehicle width direction.

In the shift lever device 600, the shift lever 606 is moved to operating positions such as the parking position 608, the reverse position 610, the neutral position 611, and the drive position 612. Therefore, in order to detect this operation position, the shift lever device 600 incorporates a shift position detection device 601.

In a shift lever device (not shown) disclosed in Patent Document 2, a shift position detection device 701 shown in FIG. 23 is incorporated.

JP 2007-333490 A Patent 2010-243287 gazette

As shown in FIG. 22, in the shift position detection device 601 disclosed in Patent Document 1, bias magnets 603 and 604 generating a magnetic field (magnetic flux) around the periphery and a counter magnet 602 interlocked with the shift lever are provided. There is. The counter magnet 602 is moved to operation positions such as the parking position 608, the reverse position 610, the neutral position 611, and the drive position 612 by the shift operation of the shift lever.

Between the bias magnets 603 and 604, one magnetoresistive element 605 that outputs a detected value according to the direction of the magnetic field (magnetic flux) is provided. The counter magnet 602 acts to pull the magnetic field (magnetic flux) generated by the two bias magnets 603, 604 to its side. Thus, when the counter magnet 602 is moved to each operating position, the magnetic field (magnetic flux) generated by the bias magnets 603, 604 is directed in the direction of each operating position.

Moreover, the magnetoresistive element 605 is provided with the magnetoresistive element of the number according to the number of operation positions. And each magnetoresistive element is provided with a sensitivity axis so that a detection value may become the maximum in the magnetic field (magnetic flux) which turns to the direction of each corresponding operation position. Thus, the position of the counter magnet 602, that is, the position of the shift lever is detected.

As described above, in the prior art disclosed in Patent Document 1, it is necessary to prepare different reluctances in the sensitivity axis direction according to the number of operation positions. In addition, it is necessary to make the sensitivity axis direction of each magnetic resistance coincide with the direction from the position of each magnetic resistance to the corresponding operation position. Therefore, there is a problem that the manufacturing process is complicated and the number of processes is large and the manufacturing cost is high.

Further, when the design of the shift lever device 600 is changed, it is necessary to change the number of magnetic resistances provided in the magnetic resistance element 605 and the sensitivity axis direction of each magnetic resistance according to the design change. That is, the shift position detection device 601 needs to change the specifications for each of the shift lever devices 600 having different specifications. As described above, the shift position detection device 601 disclosed in Patent Document 1 can be used only for the shift lever device 600 of the corresponding specification, and there is a problem that versatility is low.

As shown in FIG. 23, in the shift position detection device 701 disclosed in Patent Document 2, a cube-shaped bias magnet magnetized in the left (X1) direction on the lower side (Z1 direction) of the magnetoresistive effect sensor 702 A left (X1) direction bias magnetic field emitted from the bias magnet 703 is always applied to the magnetoresistive sensor 702.

A rectangular parallelepiped counter magnet 704 having a long side direction in the left and right (X) direction is disposed on the upper side (Z2 direction) of the magnetoresistive effect sensor 702, and the counter magnet 704 is disposed in the back (Y2) direction. In other words, the bias magnet 703 is magnetized in the direction orthogonal to the magnetization direction.

The counter magnet 704 is provided so as to be movable in two axial directions of left and right (X) direction and front and back (Y) direction. Then, when the counter magnet 704 moves and approaches the magnetoresistive sensor 702, the bias magnetic field applied to the magnetoresistive sensor 702 is changed by the influence of the magnetic field of the counter magnet 704.

Then, the change in the bias magnetic field is sensed by the magnetoresistive sensor 702 to detect that the counter magnet 704 approaches the magnetoresistive sensor 702. Therefore, the magnetoresistive effect sensor 702 and the bias magnet 703 are provided at each of the operation positions such as the reverse position 705, the neutral position 706, and the drive position 707.

Thus, in the prior art disclosed in Patent Document 2, the magnetoresistive effect sensor 702 and the bias magnet 703 are provided at each position of the operation position. Therefore, there is a problem that the price is high because the number of parts is large.

In Patent Document 1, the counter magnet 602 moves in the magnetic field emitted from the bias magnets 603 and 604 in conjunction with the shift lever. At that time, there is a problem that the smooth operation feeling of the shift lever is lost because the counter magnet 602 receives the magnetic force interference from the bias magnets 603 and 604. The same applies to Patent Document 2.

An object of the present invention is to solve such problems, and to provide a shift position detection device having high versatility, low cost, and a smooth sense of operation.

The shift position detection device according to the present invention further includes a magnet moving on the first virtual surface, a magnetic sensor disposed on the second virtual surface, and a position calculation unit that calculates the position of the magnet. The sensor is located between the pinned magnetic layer and the free magnetic layer, the pinned magnetic layer having a pinned magnetization, a free magnetic layer whose magnetization is changed by an external magnetic field, and the pinned magnetic layer and the free magnetic layer. And a nonmagnetic layer in contact with the first virtual surface, the first virtual surface being provided parallel to the second virtual surface and perpendicular to the magnetizing direction of the magnet; The surface is provided not to include the center of the magnetizing direction of the magnet, and the magnet is provided at a position where the magnetic flux generated from the magnet saturates the magnetization of the free magnetic layer of the magnetic sensor. , Sensitivity axis direction of the magnetic sensor and the magnetic Detecting the angle between the magnetic flux direction generated by the, the position calculation unit and calculates the position of the magnet from said angle.

In such an embodiment, the magnetic flux of the magnet is emitted outward from the vicinity of one end of the magnetizing direction of the magnet, and the first virtual surface is perpendicular to the magnetizing direction. And spreading outward isotropically and radially about the magnet in a state nearly parallel to the second virtual surface. Then, the magnetic flux of the magnet is directed to the other end side of the magnetizing direction of the magnet, passes through the surface including the center of the magnetizing direction of the magnet, and the first virtual surface and the second virtual surface It converges isotropically toward the other end near parallel to the surface.

Therefore, when the magnet moves on the first virtual surface, a magnetic flux that isotropically and radially spread around the magnet acts on the magnetic sensor. Therefore, the electrical resistance value of the magnetic sensor can be defined by the angle between the sensitivity axis direction of the magnetic sensor and the magnetic flux direction emitted by the magnet.

The magnetic sensor is disposed on the second virtual surface which does not include the magnetization direction center and is provided perpendicularly to the magnetization direction. Therefore, the magnetic flux emitted by the magnet acts on the magnetic sensor in a state substantially parallel to the second virtual surface. Therefore, the electric resistance value of the magnetic sensor is likely to change depending on the angle between the sensitivity axis direction of the magnetic sensor and the magnetic flux direction emitted by the magnet.

The magnet is provided at a position where the magnetic flux generated from the magnet saturates the magnetization of the free magnetic layer of the magnetic sensor. Therefore, when the magnet moves on the first virtual surface, the electric resistance value of the magnetic sensor changes depending only on the angle between the sensitivity axis direction of the magnetic sensor and the magnetic flux direction emitted by the magnet. Do.

Therefore, by detecting the change in the electrical resistance value of the magnetic sensor, it is possible to calculate the angle between the sensitivity axis direction of the magnetic sensor and the magnetic flux direction emitted by the magnet. Then, the position of the magnet can be calculated using the angle between the sensitivity axis direction of the magnetic sensor and the magnetic flux direction emitted by the magnet.

Thus, according to the invention, the position of the magnet can be detected by the at least one magnetic sensor. That is, since it is not necessary to use a bias magnet or to provide a magnetic sensor at each position of the operation position, the number of parts can be reduced. Therefore, it is possible to provide a low cost shift position detection device.

The angle between the sensitivity axis direction of the at least one magnetic sensor and the direction of the magnetic flux emitted by the magnet is not limited to the position where the operation position is disposed, and can be arbitrarily provided. Therefore, a highly versatile shift position detection device can be provided. In addition, since the manufacturing process can be simplified and the number of processes can be reduced, the manufacturing cost can be reduced.

According to the present invention, the position of the magnet can be detected without using a bias magnet. Therefore, since the magnet does not receive magnetic force interference from the bias magnet, it is possible to move and operate the shift lever with a smooth sense of operation.

Therefore, according to the present invention, it is possible to provide a shift position detection device having high versatility, low cost, and a smooth sense of operation.

It is preferable that the magnet moves so as not to overlap the magnetic sensor in plan view. With such an embodiment, the angle between the sensitivity axis direction of the magnetic sensor and the magnetic flux direction emitted by the magnet can be uniquely determined.

Further, in the present invention, it is preferable that the magnetic sensor is disposed outside the moving range of the magnet in a plan view. With such an aspect, the arrangement of the operation positions in the shift lever device can be more freely provided because the magnet is not limited to the regulation to move so as not to overlap the magnetic sensor in plan view. In addition, the arithmetic processing for detecting the angle becomes simpler.

The shift position detection device has a failure detection unit that detects a failure of the magnetic sensor, and the failure detection unit compares a reference angle at which the magnet is positioned with an angle detected by the magnetic sensor. Preferably, the failure of the magnetic sensor is detected.

When the magnetic sensor is deteriorated with time, the angle calculated from the output of the magnetic sensor deviates from the reference angle. Therefore, the failure of the magnetic sensor can be detected by comparing the reference angle with the angle.

Preferably, the magnetic sensor comprises at least two magnetic sensors. With such an aspect, it is possible to detect an arbitrary position of the magnet, thereby enabling a shift position detection device excellent in versatility.

Preferably, the magnetic sensor comprises at least three magnetic sensors. With such an aspect, it is possible to detect an arbitrary position of the magnet, thereby enabling a shift position detection device excellent in versatility. Furthermore, since three arbitrary positions of the magnet can be calculated, failure detection of the at least three magnetic sensors is enabled by comparing the three arbitrary positions of the magnet.

A shift position detection device having a failure detection unit that detects a failure of the at least three magnetic sensors, wherein the position calculation unit is configured to combine two pairs from at least three of the angles detected by the at least three magnetic sensors. Preferably, at least three positions of the magnet are selected from the combination of the two pairs, and the failure detection unit detects a failure of the at least three magnetic sensors by comparing the at least three positions.

From the combination of the two pairs of angles, the at least three positions of the magnet can be calculated. At this time, the at least three positions of the magnet are compared, and when the difference is large, in the at least three magnetic sensors, the angle between the sensitivity axis direction of each magnetic sensor and the magnetic flux direction emitted by the magnet It is determined that there is a magnetic sensor erroneously detecting. Therefore, the failure detection unit can detect the failure of the at least three magnetic sensors. And, the output from the magnetic sensor determined as a failure is not used, and only the output from the normal magnetic sensor is used. An arbitrary position of the magnet can be detected. Thus, a highly reliable shift position detection device can be provided.

Preferably, the at least three magnetic sensors are not arranged on the same straight line.

In such an embodiment, the position calculation unit can uniquely calculate the position of the magnet using the angles detected by the at least three magnetic sensors.

According to the present invention, it is possible to provide a shift position detection device having high versatility, low cost, and a smooth sense of operation.

It is a perspective view of a shift lever device in which a shift position detection device in a 1st embodiment is carried. It is a top view explaining the outline of the shift position sensing device in a 1st embodiment. It is a top view explaining the magnetic flux distribution which arises from the magnet in a 1st embodiment. FIG. 4 is a cross-sectional view of the magnetic flux distribution generated from the magnet shown in FIG. It is a cross-sectional schematic diagram of the giant magnetoresistive effect element which comprises the magnetic sensor in 1st Embodiment. It is a characteristic view of a giant magnetoresistance effect element which constitutes a magnetic sensor in a 1st embodiment. It is explanatory drawing of the resistance value of the giant magnetoresistive effect element in 1st Embodiment. It is an electric circuit diagram of a magnetic sensor in a 1st embodiment. It is a block diagram of the shift position detection apparatus in a 1st embodiment. It is a flowchart which the position calculating part in 1st Embodiment performs. It is a block diagram of the shift position detection apparatus in the modification of a 1st embodiment. It is a flowchart which the position calculating part and failure detection part in the modification of 1st Embodiment perform. It is a top view explaining the outline of the shift position sensing device in a 2nd embodiment. It is a block diagram of the shift position detection apparatus in 2nd Embodiment. It is a flowchart which the position calculating part and failure detection part in the modification of 2nd Embodiment perform. It is a top view explaining the outline of the shift position sensing device in a 3rd embodiment. It is a block diagram of the shift position detection apparatus in 3rd Embodiment. It is a flowchart which the position calculating part in 3rd Embodiment performs. It is a block diagram of the shift position detection apparatus in the modification of 3rd Embodiment. It is a flowchart which the failure detection part in the modification of 3rd Embodiment performs. It is a perspective view of the shift lever apparatus disclosed by patent document 1. FIG. It is a top view explaining the outline of the shift position sensing device indicated by patent documents 1. It is a figure explaining the outline of the shift position sensing device indicated by patent documents 2.

First Embodiment
For the shift position detection device shown in each figure, the Y direction is the front and back direction, the Y1 direction is the front direction, the Y2 direction is the back direction, the X direction is the left and right direction, and the X1 direction is the left direction and the X2 direction is the right direction It is. Further, the direction orthogonal to both the X direction and the Y direction is the vertical direction (Z direction; height direction), the Z2 direction is the upper direction, and the Z1 direction is the lower direction. In the drawings, the dimensions are appropriately made different from the actual dimensions for the sake of clarity.

The present embodiment will be described with reference to the drawings. FIG. 1 is a perspective view of a shift lever device on which the shift position detection device in the first embodiment is mounted. FIG. 2 is a plan view for explaining an outline of the shift position detection device in the first embodiment. FIG. 3 is a block diagram of the shift position detection apparatus according to the first embodiment.

The automatic vehicle is provided with an automatic transmission that automatically changes the gear ratio according to the speed of the vehicle. And, in order to switch the gear combination of the automatic transmission, a shift lever device is attached.

As shown in FIG. 1, the shift lever device 10 in the present embodiment is configured to include a substantially rod-like shift lever 11 and a box-like case 12 attached to the floor or the like of a vehicle. The shift lever 11 is attached to the case 12 so as to be movable in the longitudinal (Y) direction and in the lateral (X) direction. Then, in the shift lever device 10, the shift lever 11 is moved to the operation position such as the parking position 13, the neutral position 14, the drive position 15, the reverse position 16, and the like.

In the present embodiment, the operation positions are the parking position 13, the neutral position 14, the drive position 15, the reverse position 16 and the like, but the present invention is not limited to this. For example, a plurality of operating positions may be provided for the drive position 15, or other operating positions may be provided.

The shift position detecting device 1 is incorporated in the shift lever device 10 in order to detect the operation positions 13, 14, 15, 16 at which the shift lever 11 is positioned.

As shown in FIG. 2, the shift position detection device 1 is a magnet 5 fixed to a shift lever (not shown) and moved together, and a magnet that is disposed out of the movement line of the magnet 5 in plan view. It is configured to include the sensor 2. That is, the magnet 5 moves so as not to overlap with the magnetic sensor 2 vertically (in the Z direction) in plan view. By detecting the position of the magnet 5 using the magnetic sensor 2, each operation position 13, 14, 15, 16 at which the shift lever is positioned is calculated.

As described above, in the shift position detection device 1 of the present embodiment, the position of the magnet 5 is detected without using a bias magnet. Therefore, the magnet 5 is not subjected to magnetic force interference when moving with the shift lever. Therefore, the shift lever can be moved and operated with a smooth sense of operation.

FIG. 3 is a plan view showing the magnetic flux distribution generated from the magnet 5 in the present embodiment. FIG. 4 is a cross-sectional view of the magnetic flux distribution generated from the magnet 5 shown in FIG. 3 taken along the line AA and viewed in the arrow direction. As shown to FIG. 3, FIG. 4, the magnet 5 of this embodiment has a shape of the cylindrical body extended in an up-down (Z) direction. The end 5a on the upper (Z2) side of the magnet 5 is magnetized to the N pole, and the end 5b on the lower (Z1) side is magnetized to the S pole. Therefore, the magnetization direction is the vertical direction, and the magnetization direction center 5 c is located substantially at the center of the magnet 5 in the vertical direction.

The shift lever is moved to each operation position 13, 14, 15, 16 as shown in FIG. At that time, the end 5 b of the magnet 5 fixed to the shift lever moves on the first virtual surface 8 as shown in FIG. 4. The magnetic sensor 2 is disposed on the second virtual surface 9 which does not pass through the center of the magnet 5 in the magnetization direction. Further, as shown in FIG. 4, the first virtual surface 8 and the second virtual surface 9 are provided in parallel with each other, and are provided perpendicular to the magnetization direction of the magnet 5.

Although the magnet 5 in this embodiment is a cylindrical body, it is not limited to this. Polygonal columns are also possible. Also, the magnetization direction can be reversed, and the end 5a on the upper (Z2) side of the magnet 5 can be magnetized to the S pole and the end 5b on the lower (Z1) side can be magnetized to the N pole. It is. Further, in the present embodiment, the first virtual surface 8 and the second virtual surface 9 are flat, but the present invention is not limited to this, and may be a spherical surface or an elliptical spherical surface. good.

Since it is such an aspect, as shown in FIG. 3 and FIG. 4, the magnetic flux 7 is emitted outward from the vicinity of the upper end 5 a which is one of the magnetization directions of the magnet 5, and the magnetization direction is In a state close to being parallel to the first virtual surface 8 and the second virtual surface 9 which are perpendicular to the above, they spread isotropically and radially outward around the magnet 5. Thereafter, the magnetic flux 7 is directed to the lower end 5b side, which is the other side of the magnetizing direction of the magnet 5, and passes through a plane including the center of the magnetizing direction of the magnet 5 to form the first virtual surface 8 and the second virtual surface 8. And converges isotropically toward the lower end 5b. The magnetic flux 7 emitted or converged from a point near the outer periphery of the upper end 5a and the lower end 5b is close to parallel to the first virtual surface 8 and the second virtual surface 9 in a wider area. In the state.

Thus, when viewed from the upper and lower (Z) direction, the magnetic flux 7 generated from the magnet 5 radially spreads around the magnet 5 as shown in FIG. Therefore, the direction of the magnetic flux 7 generated from the magnet 5 acting on the magnetic sensor 2 is from the magnet 5 to the direction of the magnetic sensor 2. Moreover, since the magnet 5 is a cylindrical body, when the magnet 5 is seen from the up-down (Z) direction, it has circular isotropic shape. Therefore, the magnetic flux 7 is likely to be radiated isotropically around the magnet 5.

The magnetic sensor 2 of the present embodiment is configured to include a giant magnetoresistive effect (hereinafter, described as GMR (Giant Magneto Resistive effect)) element. For example, as shown in FIG. 5, the GMR element 2a is formed by laminating the antiferromagnetic layer 2c, the fixed magnetic layer 2d, the nonmagnetic layer 2e, and the free magnetic layer 2f in this order from below on the substrate 2b. The surface of the magnetic layer 2f is covered with a protective layer 2g. In the GMR element 2a, the magnetization direction (P direction) of the pinned magnetic layer 2d is pinned by the exchange coupling between the antiferromagnetic layer 2c and the pinned magnetic layer 2d. The magnetization direction (P direction) is directed to the left (X2) direction in parallel with the substrate 2b. In this embodiment, this direction (P direction) is taken as the sensitivity axis direction of the GMR element 2a.

The GMR element 2a is formed in a multilayer structure by stacking a ferromagnetic thin layer and a nonmagnetic layer, and it is known that the electric resistance is greatly changed by the magnetic flux from the external magnetic field. Therefore, the magnetic sensor 2 configured to include the GMR element 2a can detect the magnetic flux 7 generated from the magnet 5 with high sensitivity. The resistance value of the GMR element 2a depends on the relative angle of magnetization of both the pinned magnetic layer 2d and the free magnetic layer 2f. The resistance value is minimum when both magnetizations are parallel and directed in the same direction, and maximum when antiparallel.

In the present embodiment, the magnetic sensor 2 is configured to include the GMR element 2a, but the present invention is not limited to this. The magnetic sensor 2 can also be configured to include a tunnel effect (TMR [Tunnel Magneto Resistive Effect) element or an anisotropic magnetoresistance effect (AMR [Anisotropic Magneto Resistive effect]) element.

FIG. 6 shows a characteristic diagram of the GMR element in the present embodiment. The vertical axis is the electrical resistance value of the GMR element, and the horizontal axis is the magnetic flux density of the magnetic flux acting on the GMR element. The direction of the magnetic flux indicates the X1 direction by (-) and the X2 direction by (+). When the magnetic flux acts in the (+) direction, that is, in the X2 direction, the electric resistance has a substantially constant value of R _min and does not change. On the other hand, when the magnetic flux acts in the (−) direction, that is, in the X1 direction, the electric resistance increases when the magnetic flux density becomes lower than a predetermined value. When the magnetic flux density further drops below a predetermined value, the electrical resistance stops rising and saturates at a value of R _max which is substantially constant.

As shown in FIGS. 3 and 4, the magnetic sensor 2 is disposed in the magnetic flux generated from the magnet 5. Then, when the magnet 5 is operated to move each operation position as shown in FIG. 2, the magnetic flux 7 generated from the magnet 5 acts on the GMR element 2a (shown in FIG. 6) constituting the magnetic sensor 2. . And, when the magnet 5 is operated to move each operation position, the residual magnetic flux density of the magnet 5 is set sufficiently large so that the magnetic flux 7 saturates the magnetization of the free magnetic layer 2f constituting the GMR element 2a. ing. In other words, the magnet 5 is moved at such a position that the magnetization of the free magnetic layer 2 f is saturated by the residual magnetic flux.

Therefore, as the magnet 5, one having a large residual magnetic flux density, such as a neodymium magnet, a samarium cobalt magnet, an alnico magnet, a ferrite magnet, or a plastic magnet, is preferable. And, one having a residual magnetic flux density of 250 to 1500 mT is selected. Therefore, when the magnet 5 is operated to move each operation position, the magnetic flux 7 is maintained so that the magnetization of the free magnetic layer 2 f is saturated regardless of the distance between the magnet 5 and the magnetic sensor 2.

In this embodiment, as shown in FIG. 3, the angle formed in the direction of the magnetic flux 7 generated from the magnet 5 in the counterclockwise direction from the magnetization direction (P direction) of the pinned magnetic layer 2d (shown in FIG. 5) is θ. . At that time, regardless of the distance between the magnet 5 and the magnetic sensor 2, it is generally known that R is represented by the equation (1), where R is the electric resistance value of the GMR element 2 a constituting the magnetic sensor 2. ing.

R = R _min + (R _max -R _min ) × (1−cos θ) / 2 (1)
Therefore, the electric resistance value R of the GMR element 2a is determined by the angle θ according to the equation (1). Further, R _max and R _min are characteristic values of the GMR element 2a, and are values determined by the GMR element 2a.

FIG. 7 shows the relationship between the electrical resistance value R and the angle θ in equation (1). The vertical axis in FIG. 7 is the electrical resistance value R, and the horizontal axis is the angle θ. Numbers indicated by arrows in the figure indicate the respective operation positions. When the engine of the vehicle is started, the shift position detection device 1 is also started at the same time. When the shift lever is moved, the electric resistance value R moves from the parking position 13 to the neutral position 14, the drive position 15, and the reverse position 16 on the curve shown in FIG.

The curve shown in FIG. 7 corresponds to an angle θ which varies between 0 to 180 degrees and 180 to 360 degrees with respect to the same value of the electric resistance value R. Therefore, in the present embodiment, for example, the shift lever is set to be located at the parking position 13 when the engine of the vehicle is started. Therefore, when the engine of the vehicle is started, an angle of section 0 to 180 is assigned to the value of R. Then, when the value of R becomes larger and exceeds the peak electrical resistance value R and becomes smaller next, the angle of the section 180 to 360 is assigned to the value of R. Thus, when the shift lever moves from the parking position 13 to the neutral position 14, the drive position 15, and the reverse position 16, each operation position 14, 15, 16 can be accurately detected. Next, when the value of R becomes larger and exceeds the peak electrical resistance value R and becomes smaller next time, the angle of section 0 to 180 is assigned to the value of R. Thus, even when the shift lever is moved from the neutral position 14 to the parking position 13, the position of the parking position 13 can also be accurately detected.

In this way, by making the electric resistance value R of the GMR element 2a correspond to the angle θ on the curve shown in FIG. 7, the electric resistance value R of the GMR element 2a is unique according to the angle θ according to the equation (1). It can be decided at will. That is, the electric resistance value R of the GMR element 2a and the angle θ can be made to correspond to one to one.

As described above, as shown in FIG. 2, it occurs when the magnetic sensor 2 is disposed within the range in which the magnet 5 moves. That is, when the magnetic sensor 2 is disposed within the range in which the magnet 5 moves, the magnetic sensor 2 looks at the magnet 5 over the range of 360 degrees. However, when the magnetic sensor 2 is disposed outside the range in which the magnet 5 moves, the magnetic sensor 2 sees the magnet 5 within the range of 180 degrees. Therefore, in this case, it is not necessary to perform the above-mentioned arithmetic processing, and the electric resistance value R of the GMR element 2a is uniquely determined by the angle θ. That is, the electric resistance value R of the GMR element 2a corresponds to the angle θ one to one. As described above, it is more preferable to arrange the magnetic sensor 2 out of the range in which the magnet 5 moves, since the arithmetic processing for detecting the angle θ becomes simple.

The magnetization direction (P direction) of the pinned magnetic layer 2 d is the same as the sensitivity axis of the magnetic sensor 2. Therefore, the angle θ formed in the direction of the magnetic flux 7 generated from the magnet 5 in the counterclockwise direction from the magnetization direction (P direction) of the pinned magnetic layer 2 d is the magnetic flux of the magnet 5 acting on the sensitivity axis direction of the magnetic sensor 2 and the magnetic sensor 2 7 is an angle θ between the sensitivity axis direction of the magnetic sensor 2 and the magnetic flux direction emitted by the magnet 5.

FIG. 8 shows an electric circuit diagram of the magnetic sensor 2 in the present embodiment. As shown in FIG. 8, the magnetic sensor 2 according to the present embodiment includes four resistance portions R ₁ , R ₂ , R ₃ , and R ₄ to form a bridge circuit. The resistance unit _R 1, _{R 4,} the magnet 5 becomes a GMR element 2a (shown in FIG. 6) to vary the electric resistance by magnetic flux generated from (3, shown in FIG. 4). Further, the resistor portions R ₂ and R ₃ have fixed resistance elements which do not change due to the magnetic flux generated from the magnet 5.

The fixed resistance element can be obtained, for example, by changing the stacking order of the nonmagnetic layer 2e and the free magnetic layer 2f in FIG. That is, in the present embodiment, the fixed resistance element is formed by laminating the antiferromagnetic layer 2c, the fixed magnetic layer 2d, the free magnetic layer 2f, and the nonmagnetic layer 2e in this order on the substrate 2b from below. The surface of the magnetic layer 2e is covered with a protective layer 2g.

As shown in FIG. 8 by the magnetic flux generated from the magnet 5 (shown in FIG. 3 and FIG. 4), the midpoint potential (V ₁ ) between the resistor portion R ₁ and the resistor portion R ₂ and the resistor portion R ₃ The midpoint potential (V ₂ ) between the resistance portion R ₄ and the resistance portion R ₄ changes. Then, the midpoint potential (V ₁ ) and the midpoint potential (V ₂ ) change in reverse with increase and decrease, and the difference (V ₁ -V) between the midpoint potential (V ₁ ) and the midpoint potential (V ₂ ) ₂ ) is output via the differential amplifier 2h.

In the present embodiment, the resistor portions R ₂ and R ₃ are assumed to have fixed resistance elements, but it is also possible to have GMR elements 2 a (shown in FIG. 6). In addition, although the magnetic sensor 2 includes four resistance portions R ₁ , R ₂ , R ₃ , and R ₄ to form a bridge circuit, two resistance portions R ₁ and R ₂ are connected in series. A configuration in which the midpoint potential of the _two resistor units R ₁ and R ₂ is used as an output is also possible.

In the present embodiment, the electric resistances of the resistance portions R ₁ and R ₄ include the GMR element 2 a and the direction in which the magnetic flux 7 generated from the magnet 5 acting on the GMR element 2 a constitutes the GMR element 2 a It is the direction of magnetization of the magnetic layer 2 f. Therefore, the difference (V ₁ −V ₂ ) which is the output of the magnetic sensor 2 is determined by the angle θ formed in the direction of the magnetic flux 7 generated from the magnet 5 counterclockwise from the magnetization direction (P direction). That is, the difference (V ₁ -V ₂ ) which is the output of the magnetic sensor 2 and the angle θ between the sensitivity axis direction of the magnetic sensor 2 and the magnetic flux direction emitted by the magnet 5 have a corresponding relationship.

The corresponding relationship is, for example, the relationship between the difference (V ₁ −V ₂ ) and the angle θ using the equation (1) and the parameters such as the supply voltage and the resistance value constituting the electric circuit of the magnetic sensor 2. It can be determined as a formula.

FIG. 9 shows a block diagram of the shift position detection device 1. As shown in FIG. 9, the shift position detection device 1 is configured to have a control unit 6 in addition to the magnet 5 and the magnetic sensor 2. The control unit 6 is configured to include a central processing unit 6a (hereinafter, referred to as a CPU (Central Processing Unit)) and a memory 6b. The CPU 6a has a position calculation unit 6c. However, the magnet 5 is omitted and described in the block diagram shown in FIG.

CPU6a from the corresponding relationship of the difference between _(V 1 -V ₂₎ between the angle theta, when receiving the difference which is the output of the magnetic sensor _{2 (V} 1 -V 2), calculates a corresponding angle theta. Further, in the present embodiment, the reference angles θ _i (i = 1 to 4) corresponding to the respective operation positions 13, 14, 15, 16 are stored in the memory 6b. The reference angle θ _i (i = 1 to 4) is a value initially detected by the magnetic sensor 2. In addition, a first threshold θ _a is set and stored in the memory 6 b.

FIG. 10 shows a flowchart executed by the position calculation unit 6c in the present embodiment. The calculation process performed by the position calculation unit 6c will be described with reference to FIG. 1, FIG. 2, FIG. 9, and FIG. When the engine of the vehicle is started, the shift position detection device 1 is also started at the same time. Then, in S1, for example, the parking position 13 is selected as i = 1. In S2, the difference is calculated between the angle theta ₁ which corresponds to the position of the angle theta and a parking position 13 (i = 1), its absolute value is compared or less than the first threshold value theta _a. Then, in the case of YES, it is determined in S5 that the shift lever 11 is at the parking position 13 (i = 1). Then, information that the shift lever 11 is at the parking position 13 (i = 1) is output to the vehicle side. After that, the process returns to S1, and the calculation process is repeated. In the case of NO, the neutral position 14 is next selected as S2, for example, with i = 2.

In this embodiment, for example, the parking position 13 is determined as i = 1, the neutral position 14 as i = 2, the drive position 15 as i = 3, and the reverse position 16 as i = 4. Therefore, in S4, it is confirmed whether the selected operation position is the last reverse position 16 (i = 4). In the case of NO, the same arithmetic processing as that performed at the parking position 13 (i = 1) is performed on the neutral position 14 (i = 2). Then, the same arithmetic processing as the drive position 15 (i = 3) and the reverse position 16 (i = 4) is repeated until the operation position is determined. In the case of YES, the process returns to S1, and the same arithmetic processing is repeated from the parking position 13 (i = 1).

In this manner, when it is detected that the shift lever 11 is at the operation position 13, 14, 15, 16, the information is output to the vehicle. Thus, the vehicle can appropriately switch the gear combination of the automatic transmission according to the operation position of the shift lever 11.

The first threshold θ _a is preferably half or less of the angular difference corresponding to the adjacent operation positions in order to reliably distinguish the adjacent operation positions. Moreover, in order to prevent a malfunction, it is preferable that it is larger than the angle variation corresponding to the output variation of the magnetic sensor 2. Therefore, in the present embodiment, the first threshold θ _a is set to a value within the above range.

In the present embodiment, the magnetization direction (P direction) of the pinned magnetic layer 2d is provided in parallel to the second virtual surface 9, but the present invention is not limited to this. Even if the magnetization direction (P direction) of the pinned magnetic layer 2d is inclined with respect to the second virtual surface 9, using the cosine value of the magnetization of the pinned magnetic layer 2d to the second virtual surface 9 ( 1) Formula can be obtained.

In the present embodiment, the magnetization direction (P direction) of the pinned magnetic layer 2d is directed to the right (X2) direction, but is not limited thereto. The magnetization direction (P direction) of the pinned magnetic layer 2 d can be oriented in an arbitrary direction in a plane parallel to the second virtual surface 9.

Further, the magnetic flux 7 emitted or converged from a position near the outer periphery of the upper end 5a and the lower end 5b is in a state close to parallel to the first virtual surface 8 in a wider area. Therefore, by providing the second virtual surface 9 on which the magnetic sensor 2 is disposed so as to pass near the upper end 5a and the lower end 5b, the sensitivity axis direction of the magnetic sensor 2 can be more accurately detected. The angle θ with the direction of the magnetic flux emitted by the magnet 5 can be calculated.

In the present embodiment, as shown in FIG. 2, the magnet 5 moves so as not to overlap the magnetic sensor 2 in the vertical direction. When the magnetic sensor 2 and the magnet 5 are vertically stacked, the magnetic flux generated from the magnet 5 acts on the sensitivity axis of the magnetic sensor 2 in the vertical direction. As a result, the angle θ between the sensitivity axis direction of the magnetic sensor 2 and the magnetic flux direction emitted by the magnet 5 can not be determined uniquely. Therefore, it is preferable that the magnetic sensor 2 be disposed so as not to overlap with the magnet 5 vertically.

In this embodiment, as shown in FIG. 2, although the magnetic sensor 2 is arrange | positioned in the range which the magnet 5 moves to front and rear, right and left, it is not limited to this. It is possible to place the magnetic sensor 2 outside the range of movement of the magnet 5. At this time, since the magnetic sensor 2 and the magnet 5 are not limited to the definition that they do not overlap, the degree of freedom in the arrangement of each operation position in the shift lever device is improved. In addition, since the arithmetic processing for detecting the angle θ between the sensitivity axis direction of the magnetic sensor 2 and the magnetic flux direction emitted by the magnet 5 is simplified as described above, it is more preferable.

FIG. 11 shows a block diagram of a shift position detection device which is a modification of the present embodiment. Further, FIG. 12 shows a flowchart executed by the position calculation unit and the failure detection unit as a modification of the present embodiment. As shown in FIG. 11, in the shift position detection device according to the present modification, a failure detection unit 6d is added to the CPU 6a in the first embodiment. Then, the failure detection unit 6d detects a failure due to deterioration or the like of the magnetic sensor 2 with time. The magnet 5 is omitted and described in the block diagram shown in FIG.

The failure calculation processed by the failure detection unit 6 d will be described with reference to FIGS. 11 and 12. In FIG. 12, the calculation processing of S1 to S5 is the same as that of the first embodiment, and is performed by the position calculation unit 6c. The calculation processing of S6 to S9 is executed by the failure detection unit 6d. The operation position which is the determination result of S5 and the angle θ detected by the magnetic sensor are output from the position calculation unit 6c to the failure detection unit 6d. Then, in S6, it is determined whether the shift lever remains at the same operation position. In the case of NO, the process returns to S1 to repeat the calculation process from the beginning. In the case of YES, the average value <θ> of the angle θ is calculated in S7.

In S8, the absolute value of the difference between the reference angle theta _i corresponding to the operating position and the average value <theta> is calculated. Then, the absolute value is equal to or smaller than a second threshold value theta _b, repeat the processing returns to S1. If this absolute value is the second threshold value theta _b above, an alarm by determining the magnetic sensor 2 malfunction, we recommend replacement of the magnetic sensor 2. Further, the reference angle θ _i corresponding to the operation position, that is, the initial value θ _{i of the} angle corresponding to the operation position detected by the magnetic sensor 2 and the second threshold value θb are stored in advance in the memory 6 _b .

When temporal deterioration in the magnetic sensor 2 occurs, the angle theta is calculated from the output of the magnetic sensor 2, it deviates from the reference angle theta _i. If this deviation becomes large, the operation position can not be accurately detected. In this modification, it is to detect with the second threshold value theta _b this. Therefore, to prevent malfunctions, the second threshold value theta _b, is preferably larger than the angle variation corresponding to the output variation of the magnetic sensor 2. Also, the second threshold value theta _b, is preferably less than the first threshold value theta _a.

By choosing the second threshold theta _b below the first threshold value theta _a, during which accurately detect the respective operating position, to permit detection of such deterioration over time of the magnetic sensor 2.

Although the average value of the angle θ is used in the above method, it is also possible to use the value of the angle θ itself. The reason for using the average value of the angles θ is to improve the accuracy of failure detection. Therefore, it is also possible to execute the determination of S8 after calculating the average value several times to dozens of times. Further, by preparing a plurality of second threshold theta _b, it is also possible to partition the level of alarm.

Second Embodiment
FIG. 13 is a plan view for explaining the outline of the shift position detection device in the second embodiment. FIG. 14 shows a block diagram of the shift position detection apparatus in the second embodiment. As shown in FIG. 13, the shift position detection device of this embodiment differs from the first embodiment in that it comprises two magnetic sensors 2 and 3, and two magnetic sensors 2, A point 3 is located outside the range of movement of the magnet 5. In the present embodiment, the same reference numerals are used for the same components as in the first embodiment.

In the present embodiment, although the two magnetic sensors 2 and 3 are disposed outside the moving range of the magnet 5, the two magnetic sensors 2 and 3 are disposed within the moving range of the magnet 5. It is also possible. However, when the magnetic sensors 2 and 3 overlap the magnet 5 vertically (in the Z direction), the magnetic flux 7 generated from the magnet 5 acts on the sensitivity axes of the magnetic sensors 2 and 3 in the vertical direction. The angle θ between the sensitivity axis direction of 3 and the magnetic flux direction emitted by the magnet 5 can not be uniquely determined. Therefore, it is preferable to arrange each magnetic sensor 2 and 3 so that it does not overlap with each operation position up and down.

As in the present embodiment, disposing the two magnetic sensors 2 and 3 out of the moving range of the magnet 5 is not limited to the rule that the two magnetic sensors 2 and 3 and the magnet 5 do not overlap. The degree of freedom in the arrangement of each operation position in the shift lever device is improved. Further, as described above, it is more preferable because the arithmetic processing for detecting the angle θ between the sensitivity axis direction of each of the magnetic sensors 2 and 3 and the magnetic flux direction emitted by the magnet 5 is simplified.

In the present embodiment, as shown in FIG. 14, the CPU 6 a receives the difference (V ₁ −V ₂ ) alternately output from the two magnetic sensors 2 and 3, as in the first embodiment. The angle θ between the sensitivity axis direction of the two magnetic sensors 2 and 3 and the magnetic flux direction emitted by the magnet 5 is calculated. Then, using this angle θ, as in the modification of the first embodiment, according to the flowchart shown in FIG. 12, the position calculation unit 6c performs the determination of the operation position, and the failure detection unit 6d performs the failure determination. Do.

When the failure determination is made, the CPU 6a does not receive the difference (V _1- V ₂ ) which is the output from the magnetic sensor determined to be faulty, and executes processing to receive only the output of the normal magnetic sensor . Therefore, in the present embodiment, a highly reliable shift position detection device can be provided.

FIG. 15 shows a flowchart executed by the position calculation unit in the modification of the second embodiment. The position calculation unit of this modification executes calculation processing different from the first embodiment and the modification of the first embodiment.

An (x, y) coordinate system is set with an arbitrary position on the second virtual surface as the origin. Then, the (x, y) coordinates at which the magnetic sensor 2 and the magnetic sensor 3 are located are respectively (x ₂ , y ₂ ) and (x ₃ , y ₃ ).

CPU6a, as described above, from the corresponding relationship between the difference _(V 1 -V ₂₎ between the angle theta, when receiving the difference _(V 1 -V ₂₎ is an output of the magnetic sensors 2 and 3, each of the magnetic The angle θ between the sensitivity axis direction of the sensors 2 and 3 and the magnetic flux direction emitted by the magnet 5 is calculated. And let each angle be θ ₂ and θ ₃ .

In that case, the magnet 5 is located in the direction of the angle θ ₂ or the angle θ ₃ from each of the magnetic sensors 2 and 3 respectively. Therefore, the (x, y) coordinates at which the magnet 5 is located pass through the (x ₂ , y ₂ ) coordinates at which the magnetic sensor 2 is located, and a straight line whose inclination is tan θ ₂ and the magnetic sensor 3 are located (x ₃ , Y ₃ ), and is calculated as the point of intersection with a straight line whose inclination is tan θ ₃ .

Also, these two straight lines can be expressed by equations (2) and (3).

y = (x−x ₂ ) × tan θ ₂ + y ₂ (2)
y = (x−x ₃ ) × tan θ ₃ + y ₃ (3)
Therefore, the intersection of the straight lines of the equations (2) and (3), that is, the (x, y) coordinates at which the magnet 5 is located can be expressed by the equations (4) and (5).

_{x = (y 3 -y 2 +} x 2 × tanθ 2 -x 3 × tanθ 3) / (tanθ 2 -tanθ 3) ····· (4)
y = {y ₃ × tan θ ₂ −y ₂ × tan θ ₃ + (x ₂ −x ₃ ) × tan θ ₂ × tan θ ₃ } / (tan θ ₂ -tan θ ₃ ) (5)
FIG. 15 shows a flowchart executed by the position calculation unit in the modification of the second embodiment. The calculation process performed by the position calculation unit 6c of the present modification will be described using FIGS. 13, 14 and 15. FIG.

At S1, the CPU 6a receives the difference (V ₁ -V ₂ ) which is the output from each of the magnetic sensors 2 and 3 alternately. In S2, using this difference (V ₁ -V ₂ ), the position calculation unit 6c determines the angles θ ₂ and θ ₃ between the sensitivity axis direction of each of the magnetic sensors 2 and 3 and the magnetic flux direction emitted by the magnet 5. calculate. As the calculation method, for example, the relational expression between each difference (V ₁ -V ₂ ) and each angle θ ₂ and θ ₃ is calculated from the electric circuit configuration of each magnetic sensor 2 and 3 and Equation (1) Note that this relational expression is stored in advance in the memory 6b. In addition, constants such as R _min and R _max required for the calculation are also stored in the memory 6 b in advance. The position calculator 6c calculates the angles θ ₂ and θ ₃ from the differences (V ₁ -V ₂ ) using these equations and constants.

In S3, the position calculation unit 6c calculates (x, y) coordinates at which the magnet 5 is located, using the respective angles θ ₂ and θ ₃ and the equations (4) and (5). The equations (4) and (5) are stored in advance in the memory 6b.

At S4, for example, the parking position 13 is selected. In S5, the absolute value of the difference between the (x _i , y _i ) coordinate at which the parking position 13 is located and the (x, y) coordinate at which the calculated magnet 5 is located is the third threshold value x _a , and the fourth threshold value x _a or threshold is _{y a} or less, i.e., _{| x-x i | <x} a, and _{| y-y} i _| is compared <whether a _{y a.} When the answer is YES, it is determined in S8 that the shift lever is at the parking position 13. Then, information that the shift lever is at the parking position 13 is output to the vehicle side. After that, the process returns to S1, and the calculation process is repeated. At the time of NO, for example, the neutral position 14 is next selected in S6.

In this modification, for example, the parking position 13, the neutral position 14, the drive position 15, and the reverse position 16 are determined in order. Thus, in S7, it is confirmed whether the selected operation position is the last reverse position 16. At the time of NO, the same arithmetic processing as performed at the parking position 13 is performed on the neutral position 14. Then, the same arithmetic processing as the drive position 15 and the reverse position 16 is repeated until the operation position is determined. In the case of YES, the process returns to S1, and the same arithmetic processing is repeated from the parking position 13.

Thus, the shift position detection device of this modification detects each operation position where the shift lever is positioned. Then, when the shift lever is positioned at each operation position, the information is output to the vehicle side. As a result, the vehicle can select an appropriate gear ratio or the like corresponding to each operation position.

In the prior art in Patent Document 1 and Patent Document 2, only the (x, y) coordinates limited to each operation position of the magnet can be detected. However, in this modification, it is possible to detect an arbitrary (x, y) coordinate at which the magnet 5 is located. Therefore, according to the present modification, each operation position of the shift lever device can be provided at any position. That is, it can respond only by changing the (x _i , y _i ) coordinate corresponding to an arbitrary position of each operation position. Thus, the shift position detection device of this modification is excellent in versatility.

The third threshold value x _a and the fourth threshold value y _a are not more than half the distance between the adjacent operation positions in the X and Y directions in order to reliably divide the adjacent operation positions. Is preferred. Further, in order to prevent a malfunction, the third threshold value x _a, and the fourth threshold y _a is, X direction corresponding to the output variation of the magnetic sensor 2, and is greater than the positional variation in the Y direction preferred. Therefore, in this modification, the third threshold value x _a, and the fourth threshold y _a is set to a value in the range of the.

Third Embodiment
FIG. 16 is a plan view for explaining the outline of the shift position detection device in the third embodiment. FIG. 17 shows a block diagram of the shift position detection apparatus in the third embodiment. As shown in FIG. 16, the shift position detection device of this embodiment differs from that of the first embodiment in that it comprises three magnetic sensors 2, 3, 4 and three magnetic sensors 2, 3 and 4 are points which are disposed outside the moving range of the magnet 5. In the present embodiment, the same reference numerals are used for the same components as in the first embodiment.

In the present embodiment, although the three magnetic sensors 2, 3, and 4 are disposed out of the moving range of the magnet 5, the three magnetic sensors 2, 3, and 4 are in the moving range of the magnet 5. It is also possible to be placed at However, when the respective magnetic sensors 2, 3, 4 overlap the magnet 5 vertically (in the Z direction), the angle θ between the respective magnetic sensors 2, 3, 4 and the magnet 5 can not be determined uniquely. Therefore, it is preferable to arrange each magnetic sensor 2, 3, 4 so that it does not overlap with each operation position up and down.

As in the present embodiment, disposing the three magnetic sensors 2, 3, 4 outside the moving range of the magnet 5 does not require the three magnetic sensors 2, 3, 4 and the magnet 5 to overlap. Since it is not restricted, the degree of freedom in the arrangement of each operation position in the shift lever device is improved. Further, as described above, it is more preferable because the arithmetic processing for detecting the angle θ between the sensitivity axis direction of each of the magnetic sensors 2, 3, 4 and the magnetic flux direction emitted by the magnet 5 is simplified.

In the present embodiment, as shown in FIG. 16, the three magnetic sensors 2, 3, 4 are not arranged on the same straight line. When the three magnetic sensors 2, 3, 4 are arranged on the same straight line, the three magnetic sensors 2, 3, 4 may appear from the magnet 5 in the same direction. At this time, although it can be determined that the magnets 5 are located on the same straight line, it can not be determined where on the same straight line. In order to avoid this, it is preferable that the three magnetic sensors 2, 3 and 4 not be arranged on the same straight line.

Moreover, it is preferable to arrange | position so that two or more operation positions do not exist on the straight line which ties arbitrary two magnetic sensors. For example, when the neutral position 14 and the drive position 15 are on the straight line, the two can not be distinguished. In the case of three magnetic sensors, although they can be distinguished, one may fail and be indistinguishable.

FIG. 18 is a flowchart executed by the position calculation unit in the third embodiment. The calculation process performed by the position calculation unit in the present embodiment will be described with reference to FIGS. 17 and 18. The CPU 6a receives the differences (V ₁ -V ₂ ), which are the outputs from the three magnetic sensors 2, 3 and 4, in time series at a sufficiently small time interval. In S2, the position calculation unit 6c calculates angles θ ₂ , θ ₃ , θ ₄ formed by the sensitivity axis directions of the magnetic sensors 2, 3, 4 and the magnetic flux direction emitted by the magnet 5. This calculation method is performed in the same manner as S2 shown in FIG. 15 in the modification of the second embodiment.

In S3, a combination of two angles is selected from the _three angles θ ₂ , θ ₃ and θ ₄ . There are _three combinations of this angle: (θ ₂ , θ ₃ ), (θ ₂ , θ ₄ ), and (θ ₃ , θ ₄ ). First, at S 3, one of them is selected.

In S4, coordinates (x _p , y _p ) of the magnet 5 are calculated for the combination of angles selected in S3. This calculation method is performed in the same manner as S3 shown in FIG. 15 in the modification of the second embodiment.

At S5, for example, the parking position 13 is selected. In S6, the absolute value of the difference between the (x _i , y _i ) coordinate at which the parking position 13 is located and the (x _p , y _p ) coordinate at which the calculated magnet 5 is located is the fifth threshold value x _b , and It is compared whether it is less than or equal to a threshold value y _{b of} 6, that is, | x _p −x _i | <x _b and | y _p −y _i | <y _b . Then, in the case of YES, it is determined in S9 that the shift lever is at the parking position 13. Then, information that the shift lever is at the parking position 13 is output to the vehicle side. In the case of NO at S6, for example, the neutral position 14 is next selected at S7.

In the present embodiment, for example, the parking position 13, the neutral position 14, the drive position 15, and the reverse position 16 are determined in order. Thus, in S8, it is confirmed whether the selected operation position is the last reverse position 16. At the time of NO, the same arithmetic processing as performed at the parking position 13 is performed on the neutral position 14. Then, the same arithmetic processing as the drive position 15 and the reverse position 16 is repeated until the operation position is determined.

In this way, the calculation process is repeated until the operation position is determined for all the combinations of angles. Then, in S10, it is confirmed whether the arithmetic processing has been performed for all the combinations of angles. If NO, the arithmetic processing is repeated for the remaining combinations of angles. In the case of YES, the process returns to S1, and the arithmetic processing is repeated from the beginning.

In this way, the shift position detection device of the present embodiment shifts using the combinations of three angles θ ₂ , θ ₃ ), (θ ₂ , θ ₄ ), (θ ₃ , θ ₄ ) in order. Detect each operation position where the lever is located. Then, when the shift lever is positioned at each operation position, the information is output to the vehicle side. As a result, the vehicle can select an appropriate gear ratio or the like corresponding to each operation position.

FIG. 19 shows a block diagram of a shift position detection device in a modification of the third embodiment. FIG. 20 shows a flowchart executed by the failure detection unit in the modification of the third embodiment. In this modification, as can be understood by comparing FIG. 17 and FIG. 19, a failure detection unit 6 d is added to the third embodiment. Therefore, in the present modification, shift position detection in the third embodiment is performed, and failure detection of the three magnetic sensors 2, 3, and 4 is enabled.

The arithmetic processing performed by the failure detection unit 6d in the present modification will be described using FIGS. 16, 19 and 20. In this modification, it is performed when the magnet 5 (shift lever) remains at one of the operation positions 13, 14, 15, 16 for a predetermined time or more. That is, in S11, it is confirmed whether or not it is determined to be at the same operation position a predetermined number of times or more. In the case of YES, the process proceeds to S12. In the case of NO, the process returns to S1 of FIG. 18 to repeat the calculation process from the beginning.

The calculation process of S11 will be described in more detail. In S12 to S13 shown in FIG. 20, the operation position where the magnet 5 (shift lever) is positioned is repeatedly detected for the combination of three angles. If it is determined that the repetition is performed a predetermined number of times or more and the magnet 5 is continuously positioned at one of the operation positions 13, 14, 15, 16 during that time, the process proceeds to S12. The predetermined number of times is set between several times and several tens of times.

In S12, one of the three angle combinations is chosen. In S13, an average value is calculated using the (x _p , y _p ) coordinates of the magnet 5 corresponding to the predetermined number of times. In S14 and S15, an average value is calculated using (x _p , y _p ) coordinates of the magnet 5 corresponding to a predetermined number of times for all combinations of three angles. Thus, for the three angular combinations (θ ₂ , θ ₃ ), (θ ₂ , θ ₄ ), (θ ₃ , θ ₄ ), _three of the (x _p , y _p ) coordinates of the magnet 5 Average values (<x _p >, <y _p >) are calculated.

In S16, a combination of two average values is selected from the three average values. There are three combinations of this average value. In S17, the absolute value of the difference between (<x _m >, <y _m >), (<x _n >, <y _n >) of the two selected average values is the seventh threshold value x _c , and the eighth Compare with the threshold y _c of This comparison is also performed for the other two combinations.

In S18, it is checked whether the absolute value of the difference is greater than or equal to the seventh threshold x _c and the eighth threshold y _c with respect to the combination of the three averages. In the case of NO at S18, the process returns to S1 of FIG. 18 to repeat the calculation process from the beginning.

If YES, it is determined that there is a failed magnetic sensor among the three magnetic sensors. In that case, the absolute value of the difference calculated using the average value corresponding to the failed magnetic sensor is the seventh threshold x _c and the eighth threshold y _c or more, and the average corresponding to the failed magnetic sensor There are two values. Therefore, it is determined that the two magnetic sensors corresponding to the seventh threshold value x _c and one average value that is equal to or less than the eighth threshold value y _c are normal, and the other magnetic sensor is defective. Ru. Then, an alarm that the magnetic sensor is broken is issued, and replacement of the broken magnetic sensor is promoted.

In order to prevent a malfunction, it is preferable that the seventh threshold value x _c and the eighth threshold value y _c be larger than position variations in the X direction and Y direction corresponding to output variations of the magnetic sensor.

When the failure determination has been made, the CPU 6a can not receive the output from the magnetic sensors failure determination difference of (V 1 _{-V 2),} which is the output from the normal magnetic sensor difference (V ₁ - Process to receive only V ₂ ). Therefore, in the present embodiment, a highly reliable shift position detection device can be provided.

The differences (V ₁ -V ₂ ), which are outputs from the three magnetic sensors, are received by the CPU 6a at predetermined time intervals. Therefore, when the shift lever is moved, the angle θ calculated from the difference (V ₁ -V ₂ ), which is the output of the three magnetic sensors, deviates in time series. Therefore, in the present modification, when the magnet 5 (shift lever) remains at one of the operation positions 13, 14, 15, 16, the failure detection of the magnetic sensor is performed.

When the shift lever is moved, it is necessary to increase the operating frequency of the CPU in order to perform failure detection with high accuracy. A CPU with a high operating frequency is not preferable because it is expensive and consumes a large amount of power. Therefore, in the present modification, when the magnet 5 (shift lever) remains at one of the operation positions 13, 14, 15, 16, the failure detection of the magnetic sensor is performed, thereby reducing the cost. It is possible to provide a shift position detection device that includes a failure detection unit that has low power consumption.

1 Shift Position Detection Device 2, 3, 3 Magnetic Sensor 2a GMR Element 5 Magnet 6 Control Section 6a CPU
6b Memory 6c Position Calculation Unit 6d Failure Detection Unit 7 Magnetic flux 8 First virtual surface 9 Second virtual surface 10 Shift lever device 11 Shift lever 12 Case 13 Parking position 14 Neutral position 15 Drive position 16 Reverse position

Claims (10)

1. A magnet moving on a first virtual plane;
   A magnetic sensor disposed on the second virtual surface;
   A position calculation unit that calculates the position of the magnet;
   A position detection device having
   The magnetic sensor is located between the pinned magnetic layer and the free magnetic layer, the pinned magnetic layer having the pinned magnetization, the free magnetic layer whose magnetization is changed by an external magnetic field, and the pinned magnetic layer and the free magnetic layer. And a nonmagnetic layer in contact with the layer,
   The first virtual plane is provided parallel to the second virtual plane and perpendicular to the magnetizing direction of the magnet, and the second virtual plane is the center of the magnetizing direction of the magnet. The magnet is provided so as not to be included, and the magnet is provided at a position where the magnetic flux generated from the magnet saturates the magnetization of the free magnetic layer of the magnetic sensor, and the sensitivity axis direction of the magnetic sensor and the magnet A position detection unit that detects an angle formed by the direction of the magnetic flux emitted by the position detection unit and the position calculation unit calculates the position of the magnet from the angle.
2. A magnet moving on a first virtual plane;
   A magnetic sensor disposed on the second virtual surface;
   A position calculation unit that calculates the position of the magnet;
   A shift position detection device having
   The magnetic sensor is located between the pinned magnetic layer and the free magnetic layer, the pinned magnetic layer having the pinned magnetization, the free magnetic layer whose magnetization is changed by an external magnetic field, and the pinned magnetic layer and the free magnetic layer. And a nonmagnetic layer in contact with the layer,
   The first virtual plane is provided parallel to the second virtual plane and perpendicular to the magnetizing direction of the magnet, and the second virtual plane is the center of the magnetizing direction of the magnet. The magnet is provided so as not to be included, and the magnet is provided at a position where the magnetic flux generated from the magnet saturates the magnetization of the free magnetic layer of the magnetic sensor, and the sensitivity axis direction of the magnetic sensor and the magnet A shift position detection device characterized by detecting an angle formed by the direction of the magnetic flux emitted by the sensor and the position calculation unit calculating the position of the magnet from the angle.
3. The shift position detection device according to claim 2, wherein the magnet moves so as not to overlap the magnetic sensor in a plan view.
4. The shift position detection device according to claim 3, wherein the magnetic sensor is disposed outside a moving range of the magnet in a plan view.
5. A shift position detection device having a failure detection unit that detects a failure of the magnetic sensor,
   The failure detection unit detects a failure of the magnetic sensor by comparing a reference angle at which the magnet is located with an angle detected by the magnetic sensor. The shift position detection device according to any one of the above.
6. The shift position detection device according to any one of claims 2 to 4, wherein the magnetic sensor comprises at least two magnetic sensors.
7. The shift position detection device according to claim 6, wherein the shift position detection device has a plurality of shift positions, and each shift position is not on a straight line connecting the magnetic sensors.
8. The shift position detection device according to any one of claims 2 to 4, wherein the magnetic sensor comprises at least three magnetic sensors.
9. A shift position detection device having a failure detection unit that detects a failure of the at least three magnetic sensors,
   The position calculation unit selects a combination of two pairs from at least three of the angles detected by the at least three magnetic sensors, calculates at least three positions of the magnet from the combination of the two pairs, and the failure detection unit 9. The shift position detection device according to claim 8, wherein the failure of the at least three magnetic sensors is detected by comparing the at least three positions.
10. 10. The shift position detection device according to claim 8, wherein the at least three magnetic sensors are not arranged on the same straight line.

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