JP5108822B2 - Sensor device - Google Patents

Description

  The present invention relates to a sensor device.

  Conventionally, a rotary position sensor has been provided (see, for example, Patent Document 1). The position sensor includes a detection coil wound around a bobbin that is curved with a constant curvature, and a core that is similarly curved with a constant curvature and is inserted into the detection coil so as to freely advance and retract. The impedance of the detection coil is changed according to the amount of the core inserted into the detection coil. A displacement signal indicating position information between the core and the detection coil is output according to the constant current output from the constant current circuit and the peak value of the voltage across the detection coil determined by the impedance of the detection coil. ing.

JP 2004-29002 A (paragraph [0070] and FIG. 2)

  In the position sensor shown in Patent Document 1 described above, since the core is cantilevered, there is a possibility that the core may interfere with the bobbin due to variations in the inclination of components and parallelism. Therefore, it is necessary to set a large clearance between the core and the bobbin so that they do not interfere with each other, resulting in an increase in the size of the apparatus. In addition, there is a possibility that the impedance of the detection coil changes due to the vibration of the tip of the core due to vibration, and the output characteristics become unstable.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a small sensor device capable of obtaining stable output characteristics.

  According to the first aspect of the present invention, a detection coil, a conductive cylinder that is disposed so as to surround the detection coil, and is relatively displaced in the winding axis direction of the detection coil with respect to the detection coil, and a displacement of the conductive cylinder A control unit that outputs a position signal indicating the relative position of the conductive cylinder with respect to the detection coil based on the inductance of the detection coil that changes in response to the detection coil, and the conductive cylinder at an intermediate portion of the conductive cylinder in the displacement direction. And a movable body that is movably displaced within a predetermined range together with the conductive cylinder.

  The invention according to claim 2 includes two sets of detection units each including a detection coil and a conductive cylinder corresponding to the detection coil, and the control unit is based on a detection result of at least one of the detection units. A position signal is output.

  The invention according to claim 3 is characterized in that the conductive cylinder and the movable body are simultaneously molded.

  The invention of claim 4 is characterized by comprising a return spring for returning the movable body to a predetermined initial position.

  The invention according to claim 5 is characterized in that the conductive cylinder is formed by joining two semi-cylindrical bodies bent from a metal plate.

  The invention according to claim 6 is characterized in that the conductive cylindrical body is a resin pipe subjected to plating treatment.

  According to the first aspect of the present invention, the conductive cylinder that is displaced relative to the detection coil is supported by the movable body at the intermediate portion in the displacement direction. It is not necessary to set a large clearance in consideration of interference, and an increase in the size of the apparatus can be suppressed. Further, since it is not a cantilever structure as in the conventional example, vibration due to vibration can be suppressed, and stable output characteristics can be obtained. Further, since the conductive cylinder and the detection coil are not in contact with each other, there is an effect that it is possible to provide a sensor device having excellent aging durability.

  According to the invention of claim 2, by comparing the change in inductance detected by each of the two detection units, if one of the detection units fails, the difference between the two is outside the predetermined range. From the result, it can be determined that one of the detection units is out of order, and as a result, it is possible to prevent the detection unit from continuing to be used while it is out of order. In addition, when the detection result of one of the detection units is used as the detection result, even if one of the detection units breaks down, position detection is possible with the other detection unit, thus preventing erroneous detection. There is an effect that can be.

  According to the invention of claim 3, by simultaneously molding the conductive cylinder and the movable body, it is possible to increase the positional accuracy of both, and as a result, it is possible to suppress variations in sensor output.

  According to the invention of claim 4, since the return spring is biased when the movable body is displaced, it is possible to suppress the rattling of the movable body, and as a result, it is possible to suppress variations in sensor output. is there.

  According to the invention of claim 5, by joining two semi-cylindrical bodies bent from a metal plate, it is possible to realize a conductive cylinder that is less expensive and more accurate than the case of bending a metal pipe, and By using this conductive cylinder, there is an effect that a sensor device with improved detection accuracy can be realized.

  According to the invention of claim 6, by using the resin pipe, it is possible to realize a highly accurate conductive cylinder as compared with the case of bending the metal pipe, and it is also possible to reduce the weight. Moreover, the sensor apparatus which raised detection accuracy by using this electroconductive cylinder is realizable. Further, by forming the conductive cylinder with a resin pipe, there is an effect that interference with the detection coil can be easily prevented.

It is a disassembled perspective view of the sensor apparatus of this embodiment. (A) is a perspective view of the same as above, (b) is a perspective view of the state which removed the cover from the same as the above. It is sectional drawing same as the above. (A) is the front view of the state which removed the cover from the same, (b) is a rear view same as the above, (c) is a bottom view same as the above.

  An embodiment of a sensor device according to the present invention will be described with reference to FIGS. The sensor device according to the present invention is a rotary sensor device used for detecting the amount of rotation of the rotation mechanism, and is used as, for example, a steering angle sensor or a throttle opening sensor. In addition, if it is provided with the rotation mechanism, it is not limited to said use.

  As shown in FIG. 1, the sensor device of the present embodiment includes two sets of coil blocks 2, 2, a rotor block 3, a control board (control unit) 4, and a case 1 for housing these. ing.

  The case 1 is composed of a circular box-shaped case main body 10 whose one surface (left surface in FIG. 3) is open, and a cover 11 that is attached to the case main body 10 so as to close the opening of the case main body 10. Yes. The case body 10 is, for example, a synthetic resin molded product, and attachment pieces 12 and 12 for attaching the case body 10 to an attached portion (not shown) are integrally provided on both sides of the case body 10. Each mounting piece 12 is provided with a screw insertion hole 12a through which a mounting screw (not shown) is inserted. In addition, a rectangular box-shaped connector connecting portion 13 to which a connector (not shown) is connected is integrally provided on the lower side of the case main body 10, and the connector is inserted and connected to the lower surface of the connector connecting portion 13. The connection port 13a is open (see FIG. 2 (a) and FIG. 4 (c)). Further, a protrusion 13b for preventing the connector connected by plug-in from protruding is provided at the opening edge of the connection port 13a. Further, on the other surface side (right side in FIG. 3) of the case body 10, a bearing 14 that supports a shaft 31 of the rotor block 3 described later is provided. Further, a plurality (four in this embodiment) of L-shaped connector terminals 8 are lined up side by side in the connector connection portion 13 so that one end thereof faces the connection port 13a (on the paper surface in FIG. 3). (Vertical direction). The other end side of each connector terminal 8 is fixed by soldering at a predetermined position on the control board 4. Here, in the present embodiment, the connector terminal 8 is molded simultaneously with the connector main body 10 together with the connector connecting portion 13.

  Further, the cover 11 is a synthetic resin molded product similar to the case body 10, and is set to approximately the same size as the opening dimension of the case body 10, and is attached to the case body 10 by bonding or ultrasonic welding. It is supposed to be.

  The coil block 2 includes a coil bobbin 20 made of a synthetic resin molded product curved with a constant curvature, a detection coil 21 wound around a winding body having a small diameter in the coil bobbin 20, and one end side of the coil bobbin 20 And a pair of coil terminals 22, 22 electrically connected to both ends of the detection coil 21. And in this embodiment, each coil block 2 and 2 is arrange | positioned in the point-symmetrical position centering | focusing on the central axis of case main body 10, respectively (refer FIG.2 (b) and FIG.4 (a)).

  The rotor block 3 is disposed on a disc-shaped movable body 30 that is rotatably arranged with respect to the case 1 and one end side (right side in FIG. 3) of the movable body 30, and a sensor lever 5 described later is attached thereto. The shaft 31, conductive cylinders 32 and 32 supported by the movable body 30 via cylindrical attachments 34 and 34 extending from the side of the movable body 30, and the movable body 30 at a predetermined initial position. It is comprised with the return spring 33 for making it return. In addition, said movable body 30 and both attachments 34 and 34 are integrally molded products by a synthetic resin.

  The conductive cylinder 32 is formed in a substantially cylindrical shape by interfacial bonding of two semi-cylindrical bodies bent from, for example, a thin aluminum plate. In this embodiment, both sides of the movable body 30 are shown in FIG. In addition, the detection coils 21 are arranged in a corresponding manner. Here, in the present embodiment, the movable body 30 and the conductive cylinder 32 are formed at the same time. As a result, the positional accuracy of the movable body 30 and the conductive cylinder 32 can be increased. Accordingly, variations in sensor output can be suppressed. Each conductive cylinder 32 is supported by a fixture 34 at an intermediate portion in the central axis direction. The inner diameter of each conductive cylinder 32 is set to a dimension that does not interfere when the conductive cylinder 32 moves relative to the corresponding detection coil 21. Here, each detection coil 21 and each conductive coil 32 corresponding to each detection coil 21 constitute a detection unit, and the sensor device of this embodiment includes two sets of detection units.

  The control board 4 is composed of a printed board 40 formed to have substantially the same size as the opening size of the case body 10, and through holes 41 are provided in portions corresponding to the connector terminals 8 described above, and each coil terminal. Through-holes 42 are respectively provided in portions corresponding to 22. Further, electronic components such as a microcomputer are also mounted on the printed circuit board 40. In the microcomputer, the relative position of the conductive cylinder 32 with respect to the detection coil 21 (sensor lever 5) based on the change in inductance of the detection coil 21. And the above information is output to an external device (not shown) via the connector terminal 8.

  The sensor lever 5 has a substantially rectangular plate-shaped main piece 50, and an insertion hole 51 through which the shaft 31 is inserted is provided in a substantially central portion of the main piece 50. Further, a pair of leg pieces 52, 52 extending in a direction orthogonal to the main piece 50 is bent at one end side in the longitudinal direction of the main piece 50 (lower side in FIG. 1). The leg pieces 52 and 52 are adapted to be attached to the rotating mechanism. The shape of the insertion hole 51 is the same as the shape of the shaft 31, and the opening dimension of the insertion hole 51 is set to be approximately the same as the outer diameter dimension of the shaft 31. The sensor lever 5 is rotatably attached to the sensor device as shown in FIG. 4B by inserting the shaft 31 through the insertion hole 51 and then screwing it with the nut 7. In this state, an E-shaped ring 6 is attached between the case body 10 and the sensor lever 5 (see FIG. 3).

  Next, the operation of this sensor device will be described. First, in a state where the rotation mechanism is not rotating, the rotor block 3 is located at a predetermined initial position. Here, the predetermined initial position is a position where the detection coil 21 of each coil block 2 is not inserted into the conductive cylinder 32 of the corresponding rotor block 3. At this time, the rotor block 3 is moved by the return spring 33. It is in a neutral position that is not biased. When the rotating mechanism is rotated from this state, the sensor lever 5 rotates in conjunction with the rotating mechanism, and accordingly, the rotor block 3 also rotates in the same direction. Furthermore, since both the conductive cylinders 32 and 32 rotate in the same direction along the winding axis direction of the detection coil 21, each detection coil 21 is inserted into the corresponding conductive cylinder 32. As a result, the inductance of each detection coil 21 changes. The control board 4 detects the change in inductance via the coil terminals 22 and 22 and calculates the relative position of the conductive cylinder 32 with respect to the detection coil 21 based on the detected change in inductance. Further, the control board 4 creates a position signal indicating the calculated relative position and outputs the position signal to an external device via the connector terminal 8. Thereafter, when the rotation mechanism is returned to the original position, the rotor block 3 returns to a predetermined initial position by the spring return force of the return spring 33. In the present embodiment, it is configured to detect a change in inductance of both the detection coils 21 and 21. For example, one of the detection coils 21 and 21 is detected by comparing the change in inductance detected by each of the two detection units. If the unit fails, the difference between the two will fall outside the specified range, so it can be judged from the comparison result that either one of the detectors has failed, and as a result, the detector can be prevented from continuing to be used with the failure. it can. In addition, when the detection result of one of the detection units is used as the detection result, even if one of the detection units breaks down, position detection is possible with the other detection unit, thus preventing erroneous detection. Can do.

  Thus, according to the present embodiment, the conductive cylinder 32 that is relatively displaced with respect to the detection coil 21 is supported by the movable body 30 at an intermediate portion in the central axis direction. Since the swing width at both ends of the conductive cylinder 32 can be reduced and the possibility of interference is reduced as a result, it is not necessary to set a large clearance in consideration of the interference between the two as in the conventional cantilever structure. , Increase in size of the apparatus can be suppressed. Further, since it is not a cantilever structure as in the conventional example, vibration due to vibration can be suppressed, and stable output characteristics can be obtained. Furthermore, since the conductive cylinder 32 and the detection coil 21 are not in contact with each other, it is possible to provide a sensor device having excellent durability over time.

  Moreover, since the spring 30 is biased by the return force of the return spring 33 when the movable body 30 is displaced, the play of the movable body 30 can be suppressed, and as a result, variations in sensor output can be suppressed. Furthermore, according to the present embodiment, the conductive cylinder 32 is realized at a lower cost and with higher accuracy than the case of bending a metal pipe by interfacially bonding two semi-cylindrical bodies bent from a thin aluminum plate. In addition, by using the conductive cylinder 32, a sensor device with improved detection accuracy can be realized. Further, in the method using the core as in the conventional example, since the fluctuation with respect to the temperature is generally larger as the material has a higher magnetic permeability, the output fluctuation becomes large. As described above, by configuring the conductive cylinder 32 with a material having a small characteristic variation due to temperature, it is possible to suppress an output variation accompanying a temperature change. As a result, the sensor device can be realized by small-scale calibration.

  Here, in this embodiment, the case of the conductive cylinder 32 made of two semi-cylindrical bodies bent from a thin aluminum plate has been described as an example. However, the conductive cylinder is limited to this embodiment. Instead, for example, a resin pipe may be plated. In this case, a highly accurate conductive cylinder can be realized as compared with the case of bending a metal pipe, and the weight can be reduced. In addition, a sensor device with improved detection accuracy can be realized by using this conductive cylinder. Further, by forming the conductive cylinder with a resin pipe, interference with the detection coil can be easily prevented.

  In this embodiment, the conductive cylinder is made of aluminum. However, since the sensor device detects a change in the eddy current on the surface of the conductive cylinder as a change in the inductance of the coil, the sensor apparatus is made of aluminum. It is not limited, and other materials may be used as long as they have conductivity. In addition, it is better if the material has a small characteristic variation with temperature.

4 Control board (control unit)
21 Detection coil 30 Movable body 32 Conductive cylinder

Claims (6)

  A detection coil, a conductive cylinder that is disposed so as to surround the detection coil, and is relatively displaced in the winding axis direction of the detection coil with respect to the detection coil, and a detection coil that changes according to the displacement of the conductive cylinder A control unit that outputs a position signal indicating the relative position of the conductive cylindrical body with respect to the detection coil based on the inductance of the conductive cylinder, and the conductive cylindrical body is supported by an intermediate portion of the conductive cylindrical body in the displacement direction. And a movable body movably displaced within a predetermined range.   Two sets of detection units each including the detection coil and the conductive cylinder corresponding to the detection coil are provided, and the control unit outputs the position signal based on a detection result of at least one of the detection units. The sensor device according to claim 1, wherein the sensor device outputs the sensor device.   The sensor device according to claim 1, wherein the conductive cylinder and the movable body are formed simultaneously.   The sensor device according to any one of claims 1 to 3, further comprising a return spring for returning the movable body to a predetermined initial position.   The sensor device according to any one of claims 1 to 4, wherein the conductive cylinder is configured by joining two semi-cylindrical bodies bent from a metal plate.   The sensor device according to claim 1, wherein the conductive cylindrical body is a resin pipe that has been subjected to a plating treatment.

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