JP2008076066A - Sensor assembly - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To heighten detection accuracy, and to miniaturize as a device. <P>SOLUTION: This sensor assembly 10 is equipped with a detection shaft 14, an angle sensor 40 mounted on the detection shaft 14, and a noncontact magnetostrictive type torque sensor 48 mounted on the detection shaft 14 adjacently to the angle sensor 40. The detection shaft 14 is interposed between a transmitting shaft for transmitting a rotating torque when being used and a transmitted shaft to which the rotating torque is transmitted, and the rotating torque transmitted from the transmitting shaft to the transmitted shaft and a rotation angle by the rotating torque are detected by both sensors 40, 48. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a sensor assembly including an angle sensor that detects a rotation angle and a torque sensor that detects a rotation torque.

  Some conventional sensor assemblies are incorporated in the torque controlled pulse tool shown in FIG. The torque-controlled pulse tool shown in FIG. 10 is the tool disclosed in FIG. 1 of Japanese Patent Laid-Open No. 8-267368. The code | symbol shown in FIG. 10 is a code | symbol attached | subjected to the same gazette. As shown in the schematic configuration in FIG. 10, the shaft to which the angle sensor 100 is attached and the shaft to which the torque sensor 200 is attached are separate bodies, and both the shafts are connected at a fastening point 300 indicated by an arrow. It has become. In this torque control type pulse tool, since the angle sensor 100 and the torque sensor 200 are attached to different shafts, the mounting error of the angle sensor 100 and the torque sensor 200 and the rotational slip at the fastening portion 300 are detected. This may affect the accuracy and may result in a rotational torque transmission control error.

Conventionally, a torque sensor having an angle sensor function has been proposed. As shown in FIG. 11, the configuration of the angle sensor 500 includes two disks provided with a space in the axial direction of the shaft 400. The torsion amount of 600 is converted into torque, and in order to increase the resolution of torque detection, it is necessary to increase the distance between the two angle sensors 500 and 600, which leads to an increase in the length of the shaft 400. In addition, in the case where the length of the shaft 400 is suppressed and circuit processing is performed, a complicated and expensive circuit is required.
JP-A-8-267368

  The problem to be solved by the present invention is to increase the detection accuracy and reduce the size of the apparatus.

  A sensor assembly according to the present invention includes a single detection shaft interposed between a plurality of shafts in a torque transmission path, and an angle sensor for detecting a rotation amount (angle) of the detection shaft is mounted on the detection shaft. In addition, a non-contact magnetostrictive torque sensor is arranged on the detection shaft in proximity to the angle sensor.

  The sensor is not limited to being attached to the circuit board as in the embodiment, and may include attaching the whole to the detection shaft through an appropriate attachment member or mechanism by integrally molding with resin.

  This rotation detection can include a rotation angle, a rotation speed, and the like.

  According to the present invention, since the angle sensor and the torque sensor are mounted close to a single detection shaft, the mounting error of each of the angle sensor and the torque sensor is a case where each is mounted on a separate shaft. It is possible to reduce the rotational torque transmission control error and the rotational slip due to the fact that the conventional angle sensor mounting shaft and torque sensor mounting shaft are connected at the fastening portion is eliminated. Will be able to. Furthermore, in the present invention, since it is not necessary to increase the length of the detection shaft in order to increase the resolution of torque detection, the sensor assembly can be miniaturized, and in addition, they are independent in detection. Therefore, by arranging them close to each other, the detection shaft can be made shorter and the size can be reduced.

  In a preferred aspect of the present invention, a pair of disk-shaped circuit boards mounted with circuit parts for electrically processing the detection signals of the two sensors at a distance from the detection shaft are arranged opposite to each other, The torque sensor is constituted by a shaft portion between the two circuit boards facing each other and a magnetic sensor for detecting a change in magnetic characteristics of the shaft portion in a non-contact manner.

  In a preferred aspect of the present invention, a pair of bearings are provided at a predetermined interval on the detection shaft, and the detection signals of the two sensors are electrically transmitted to the shaft portion between the bearings at a predetermined interval. A pair of disk-like circuit boards loaded with circuit components to be processed are arranged opposite to each other, and the angle sensor is provided in a shaft portion between one bearing and one circuit board, and a shaft between both circuit boards is opposed to each other. It is to provide a torque sensor in the part.

  According to a preferred aspect of the present invention, one bearing is a double bearing and a cylindrical housing is placed on the double bearing, and the angle sensor is detected on the inner surface of the cylindrical housing and the substrate surface of one circuit board. A light encoder and a light receiver mounted opposite to each other in the axial direction of the shaft, and a rotary plate with a slit interposed between the light emitter and the light receiver so as to rotate integrally with the detection shaft, to form an optical encoder configuration. It is.

  In a preferred aspect of the present invention, a pair of bearings are provided at a predetermined interval on the detection shaft, and the detection signals of the two sensors are electrically transmitted to the shaft portion between the bearings at a predetermined interval. A pair of disk-like circuit boards on which circuit components to be processed are mounted is provided, and the angle sensor and the torque sensor are provided on a shaft portion between the opposite sides of both circuit boards.

  In a preferred aspect of the present invention, the angle sensor is mounted on the opposing substrate surfaces of the circuit boards so as to face each other in the axial direction of the detection shaft, and between the light emission and light reception means. An optical encoder configuration is formed by a rotating plate with a slit interposed in the shaft portion so as to be integrally rotatable with the shaft portion.

  ADVANTAGE OF THE INVENTION According to this invention, detection accuracy can be raised and size reduction as an apparatus can be achieved.

  Hereinafter, a sensor assembly according to an embodiment of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 shows a use state of the sensor assembly 10 of the embodiment. The sensor assembly 10 includes a detection shaft 14 on which a sensor cover 12 containing a non-contact angle sensor and a non-contact magnetostrictive torque sensor not shown in FIG. 1 is mounted. The detection shaft 14 is interposed between a transmission shaft 16 that transmits rotational torque in use and a transmitted shaft 18 that transmits the rotational torque, in a state where the detection shaft 14 is fastened by fastening portions 20 and 21. The rotational torque transmitted from 16 to the transmitted shaft 18 and the rotational angle due to this rotational torque can be detected by the two sensors in the sensor cover 12. The transmission shaft 16 is rotationally driven by a driving device 22 such as a motor, and the transmitted shaft 18 is mounted with a rotating body 23 to be measured at the tip, and the rotating body 23 is immersed in a liquid or a solid solution 24 to rotate the transmission shaft 16. Is rotated in the direction of the arrow.

  FIG. 2 shows a detection configuration by the sensor assembly 10. The sensor assembly 10 is magnetically shielded by a sensor cover 12 so that a torque detection signal and an angle detection signal can be output through the interface connector 26.

  FIG. 3A shows a change in the torque detection signal by the non-contact magnetostrictive torque sensor. In FIG. 3A, the horizontal axis represents torque, and the vertical axis represents a torque sensor detection signal (sensor output voltage). FIG. 3B shows an angle detection signal. The horizontal axis in FIG. 3B represents the angle, that is, the amount of rotation of the detection shaft 14. 3A and 3B, in the sensor assembly 10 according to the embodiment, the angle sensor and the non-contact magnetostrictive torque sensor individually receive the angle detection signal and the torque detection signal. Can be output.

  4 and 5 show a configuration example of the sensor assembly 10.

  First, the sensor assembly 10 will be described with reference to FIG.

  A pair of bearings 28 and 30 are provided on the detection shaft 14 at a predetermined interval. One bearing 28 has a double bearing configuration. These bearings 28 and 30 are preferably ball bearings composed of an inner ring fixed to the detection shaft 14, an outer ring, and a plurality of balls interposed between the two rings. The double bearing is composed of two rows of inner rings in the axial direction, two outer rows in the same axial direction, and balls that are a plurality of rolling elements arranged so as to roll between the inner and outer rings in both rows. Yes.

  A cylindrical housing 32 is put on the double bearing 28. Between the bearings 28 and 30, disk-shaped circuit boards 34 and 36 are arranged to face each other. An opening having a diameter larger than the diameter of the detection shaft 14 is formed at the center of both the circuit boards 34 and 36, and each of the circuit boards 34 and 36 is connected to the detection shaft 14 even when the detection shaft 14 rotates. On the other hand, it does not rotate integrally. The cylindrical housing 32 and the circuit boards 34 and 36 are surrounded by a sensor cover 38. The cylindrical housing 32, the circuit boards 34 and 36, and the sensor cover 38 rotate integrally with the outer rings of the bearings 28 and 30, respectively. Accordingly, the cylindrical housing 32, the circuit boards 34 and 36, and the sensor cover 38 are configured not to rotate even when the detection shaft 14 rotates. The interface connector 26 is disposed on the circuit board 36. The circuit components of the sensor assembly 10 are mounted on both circuit boards 34 and 36.

  The angle sensor 40 of the embodiment has a configuration of an optical rotary encoder. That is, the angle sensor 40 includes a light emitting diode 42 fixed to the inner surface 32a of the cylindrical housing 32 covering the bearing 28, a photodiode 44 fixed to the substrate surface of one circuit board 34, and both the diodes 42, 44. It is comprised by the rotating plate 46 with a slit fixed to the detection shaft part between them so that integral rotation was possible.

  The torque sensor 48 is a non-contact magnetostrictive torque sensor, and the shaft portion 50 whose magnetic characteristics change due to the torque stress between the opposing circuit boards 34 and 36 and the change in magnetic characteristics of the shaft portion 50 are detected in a non-contact manner. And a magnetic sensor 52 that performs the above operation. The magnetic sensor 52 is mounted on a board 54 that is passed between the circuit boards 34 and 36. With this mounting, the magnetic sensor 52 faces the shaft portion 50 in parallel.

Specifically, a magnetic material, a non-magnetic material, and a composite magnetic material (published on page 33 of Hitachi Metals Technical Report Vol. 13 (1997)) can be used for the shaft portion 50. In order to give this shaft portion 50 a magnetostrictive torque sensor function,
(1) A magnetized portion in which the shaft portion 50 is directly magnetized (see Japanese Patent No. 3164590)
(2) A magnetized ring-shaped object is fixed to the shaft portion 50 (refer to Japanese Patent Publication No. 9-511832).

(3) A magnetized portion in which the shaft portion 50 is subjected to predetermined processing (for example, processing for imparting magnetic anisotropy) (see Japanese Patent No. 2811980).
(4) Fix the ring-shaped object that has been subjected to the above-mentioned processing on the shaft (see Torque ducer on the Kubota website)
It can be set as this structure.

  In order to realize each, first, when a magnetic material is used for the detection shaft 14, the shaft portion 50 is magnetized as shown in the above (1) and (3), or the magnetic flux is passed. In this case, in the above (1), in order to reduce the influence of the magnetic flux passing through the detection shaft 14 from the outside, when only the portion to be magnetized is magnetized, the composite magnetic material can also be a candidate for the material to be used. On the other hand, when a non-magnetic material is used for the detection shaft 14, the detection shaft 14 itself is not magnetized as shown in (2) and (4) above. This is necessary to prevent the magnetic flux from being transmitted into the detection shaft 14.

  In the sensor assembly 10 having the above-described configuration, a single detection shaft 14 is provided with an angle sensor function and a torque sensor function, and a photodiode that is a sensor portion of the angle sensor 40 or the torque sensor 48 that extracts a detection signal. 44 and the magnetic sensor 52 are configured so as not to contact the detection shaft 14, so that the angle sensor 40 and the torque sensor 48 are attached to separate shafts as in the prior art, and are not connected to each other by a fastening portion. Assembling to the detection shaft 14 is possible, and assembling errors due to assembling to separate shafts, output errors due to slipping at the fastening portion, and the like are eliminated.

  Further, the detection shaft 14 is used by being fastened with fastening portions 20 and 21 between a transmission shaft 16 for transmitting rotational torque and a transmitted shaft 18 to which the rotational torque is transmitted. The rotation torque transmitted to the motor and the rotation angle by the rotation torque are detected by the sensors 40 and 48 assembled to the detection shaft 14, so that the angle detection and the torque detection can be simultaneously and accurately measured and detected. It becomes like this. Further, since the magnetostrictive torque sensor function is given to the detection shaft 14 by the above (1) to (4), for example, in the above (1) and (2), the change of the detection shaft 14 caused by the torque applied to the detection shaft 14, that is, the twist Thus, torque can be detected when the amount of change in torque and the amount of change in magnetic field are proportional to the change in the magnetic field around the detection shaft 14 (inverse magnetostriction phenomenon). In (3) and (4) above, torque detection is possible because the magnetic flux signal generated when excited at high frequency due to the inverse magnetostriction phenomenon is proportional to the amount of torque change. In the above, the angle and torque can be detected without contact with the detection shaft 14, and the configuration of the sensor assembly 10 is greatly simplified. Further, since this sensor assembly 10 uses the inverse magnetostriction phenomenon that the magnetic characteristic of the detection shaft 14 changes due to the torque stress acting on the detection shaft 14, so long as the magnetism changing due to the torque can be read. There is no need to forcibly increase the length of the detection shaft 14, and the overall length is increased by increasing the length of the shaft in order to increase the resolution of torque detection, or at a complex altitude for improving the resolution. Expensive technology is no longer needed.

  Furthermore, since angle detection and torque detection can be performed independently of each other, it is not necessary to consider increasing the angle detection resolution in accordance with the torque detection resolution as in the prior art. Rather, since the resolution of angle detection can be lowered, the configuration can be changed according to the specifications required for the installation location of the sensor assembly 10. Further, when the resolution is increased in the angle sensor 40, complicated circuits and expensive members are required. However, in the sensor assembly 10 of the embodiment, the cost can be reduced by reducing the resolution of the angle sensor 40.

  In the sensor assembly 10 shown in FIG. 5, a pair of bearings 28, 30, one of which is a double bearing 28, are provided on the detection shaft 14 at a predetermined interval, and the circuit board 34, described above is disposed on the shaft portion between the bearings 28, 30. 36, and the angle sensor 40 and the torque sensor 48 are provided on the shaft portion between the opposing surfaces of the circuit boards 34 and 36, and the angle sensor 40 is used as an optical rotary encoder to oppose the circuit boards 34 and 36. A photodiode 44 and a light receiving diode 42 mounted on the substrate surface so as to face each other in the axial direction of the detection shaft 14, and a shaft portion between both the light emitting and receiving diodes 42, 44 so as to be integrally rotatable with the shaft portion. And a rotary plate 46 with slits.

  Circuit parts constituting the detection circuit shown in FIG. 6 can be mounted on the circuit boards 34 and 36. The detection circuit includes an angle sensor 40 attached to the detection shaft 14, amplifiers 54 and 56 for amplifying detection signals of the torque sensor 48, and A / D conversion for A / D conversion of the outputs of the amplifiers 54 and 56, respectively. Devices 58 and 60, a CPU 62 for capturing the outputs of the A / D converters 58 and 60, and LPFs (low pass filters) 64-68 for filtering the CPU 62 outputs. The first LPF 64 outputs an error detection signal, the second LPF 66 outputs an angle detection signal, and the third LPF 68 outputs a torque detection signal via the D / A converter 70.

  The output of the A / D converter 58 for A / D converting the angle sensor output can also be used for angle detection. Further, temperature compensation, reference setting, torque limit, and the like are input to the CPU 62, and the CPU 62 performs necessary control processing based on these inputs. The torque detection output of the third LPF 68 can be fed back to the A / D converters 58 and 60 and used to control the A / D conversion operation.

  7 shows a conceptual configuration of the sensor assembly of FIG. 4, FIG. 8 shows a conceptual configuration of the sensor assembly of FIG. 5, and FIG. 9 shows a conceptual configuration of the conventional sensor assembly. As shown in these drawings, first, in the sensor assembly 10 of FIG. 7, an angle sensor 40 and a non-contact magnetostrictive torque sensor 48 are arranged in parallel in a sensor cover 38 attached to the detection shaft 14. FIG. In the sensor assembly 10 shown in FIG. 8, the angle sensor 40 and the non-contact magnetostrictive torque sensor 48 are arranged so as to overlap each other in the sensor cover 38 attached to the detection shaft 14. In the sensor assembly shown in FIG. , 500, the angle sensor 100 and the torque sensor 200 are arranged, and both shafts 400, 500 are fastened by the fastening member 300.

  In the sensor assembly 10 of the embodiment, as shown in FIGS. 7 and 8, the mounting error of each of the angle sensor 40 and the torque sensor 48 on the single detection shaft 14 is smaller than that in the case where each is mounted on a separate shaft. In addition, the rotational slip due to the fact that the conventional angle sensor mounting shaft 400 and the torque sensor mounting shaft 500 are connected by the fastening portion 300 is eliminated, and the transmission control error of the rotational torque is suppressed to a small extent. Will be able to.

  The light emitting diode 42 in the angle sensor 40 and the magnetic sensor 52 in the torque sensor 48 can be integrated with the detection shaft 14 by resin molding or positioned by an appropriate positioning mechanism without being attached to the circuit board.

  In the present invention, since it is not necessary to increase the length of the detection shaft 14 in order to increase the resolution of torque detection, the sensor assembly 10 can be downsized.

  The angle sensor 14 is not limited to an optical type, and may be another type of angle sensor such as a magnetic type, a capacitance type, or a resolver type.

FIG. 1 is a view showing an example of use of a sensor assembly according to an embodiment of the present invention. FIG. 2 is a diagram used for explaining output extraction of the angle detection signal and the torque detection signal of the sensor assembly of the embodiment. FIG. 3A is a diagram showing a change in the detection signal with respect to the torque, and FIG. 3B is a diagram showing a change in the angle detection signal with respect to the angle. FIG. 4 is a diagram illustrating a configuration of the sensor assembly according to the embodiment. FIG. 5 is a diagram illustrating a configuration of another sensor assembly according to the embodiment. FIG. 6 is a diagram illustrating a detection circuit of the sensor assembly according to the embodiment. FIG. 7 is a view showing the concept of the sensor assembly of FIG. FIG. 8 is a view showing the concept of the sensor assembly of FIG. FIG. 9 is a view showing the concept of a conventional sensor assembly. FIG. 10 is a diagram showing a configuration of a torque control type pulse tool described in Japanese Patent Laid-Open No. 8-267368. FIG. 11 is a diagram showing a configuration of a conventional torque sensor having an angle detection function.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Sensor assembly 12 Sensor cover 14 Detection shaft 16 Transmission shaft 18 Transmitted shaft 28, 30 Bearing 32 Cylindrical housing 34, 36 Circuit board 38 Sensor cover 40 Angle sensor 42 Light emitting diode 44 Photo diode 46 Rotary plate 48 with a slit Torque sensor

Claims (6)

  A single detection shaft that is interposed between a plurality of shafts in the torque transmission path is provided, and an angle sensor that detects a rotation amount (angle) of the detection shaft is mounted on the detection shaft, and further on the detection shaft A sensor assembly, wherein a non-contact magnetostrictive torque sensor is disposed close to the angle sensor.   A pair of disk-like circuit boards on which circuit parts for electrically processing the detection signals of the two sensors are mounted on the detection shaft so as to be rotatable and spaced apart from each other, and the torque sensors are arranged on both circuit boards. The sensor assembly according to claim 1, wherein the sensor assembly is configured by a shaft portion between the facing portions and a magnetic sensor that detects a change in magnetic characteristics of the shaft portion in a non-contact manner.   A pair of bearings are provided on the detection shaft at a predetermined interval, and a pair of circuit parts that are rotatable and electrically process detection signals of the sensors at a predetermined interval are mounted on the shaft portion between the bearings. The above-mentioned angle sensor is provided on the shaft portion between the one bearing and the one circuit board, and the torque sensor is provided on the shaft portion between the two circuit boards. The sensor assembly according to claim 1.   One bearing is a double bearing and a cylindrical housing is placed on the double bearing. The angle sensor is opposed to the inner surface of the cylindrical housing and the substrate surface of one circuit board in the axial direction of the detection shaft. 4. The optical encoder configuration according to claim 3, wherein the light emitting means and the light receiving means are attached, and a rotary plate with a slit interposed between the light emitting and light receiving means so as to be integrally rotatable with the detection shaft. The sensor assembly as described.   A pair of bearings are provided on the detection shaft at a predetermined interval, and a pair of circuit parts that are rotatable and electrically process detection signals of the sensors at a predetermined interval are mounted on the shaft portion between the bearings. 2. The sensor assembly according to claim 1, wherein the disk-shaped circuit board is provided, and the angle sensor and the torque sensor are provided on a shaft portion between the two circuit boards facing each other.   The angle sensor is mounted on the opposite substrate surfaces of the circuit boards so as to face each other in the axial direction of the detection shaft, and the shaft portion is integrated with the shaft portion between the light emission and light reception means. The sensor assembly according to claim 5, wherein an optical encoder configuration is formed by a rotating plate with a slit interposed so as to be rotatable.

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