JPH064617U - Rotation detector - Google Patents

Abstract

(57) [Abstract] [Purpose] To effectively use a magnetic sensor to eliminate the coil and reduce the size of the device. [Structure] First and second gear plates 2 and 3 having salient poles 2a and 3a projecting at a constant pitch on the outer periphery are provided coaxially, and a rotor 1 that rotates by interposing a magnet 5 between the two gear plates is provided. A plurality of stators 6, which are provided with protruding portions 6a7a facing the outer circumferences of the salient poles 2a, 3a of the rotor 1 and provided with gaps 6b, 7b concentrically with the rotor 1, respectively. 7 and magnetic sensors H1 and H2 arranged in the gap of the stator to detect the changing magnetic field. [Effect] By rotating the rotor, an electric signal proportional to the rotation of the rotor can be directly detected from the magnetic sensor in the gap, and a coil such as a conventional resolver is not required. Can be converted.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a rotation detecting device that detects a magnetic field change due to relative rotation between a rotor and a stator by a magnetic sensor to obtain a predetermined electric signal.

[0002]

[Prior art]

 Conventionally, as this type of rotation detecting device, for example, a multi-pole resolver as disclosed in JP-A-1-140018 is known. This multi-pole resolver will be described with reference to FIG. 6. The stator 10 is stacked by inserting the non-magnetic materials 14, 15 between the three magnetic materials 11, 12, 13 so that each magnetic material 11, 12, 13 has a stack. Three salient poles 11a to 11c, 12a to 12c, 13a to 13c are provided, and teeth 16 are formed at the tips of these salient poles. The teeth 16 of the salient pole provided on each magnetic body form the same phase, and the teeth 16 of the salient pole provided on each of the magnetic bodies 11, 12, and 13 have a phase {(1/3) + m} p (Where p is the tooth pitch and m is an integer). Coils 17a to 17c, 18a to 18c, and 19a to 19c are wound around the magnetic bodies 11, 12, and 13, respectively.

A rotor made of a magnetic material is arranged on the outer periphery of the stator 10, and teeth 21 facing the above teeth 16 at substantially the same pitch are formed. Then, a sine wave voltage of a predetermined voltage is applied to each of the coils 17a to 17c, 18a to 18c, 19a to 19c from the three-phase oscillator 22. The rotation angle and the rotation speed of the multi-pole resolver having the above configuration are measured by measuring the current flowing through the coils 17a to 17c, 18a to 18c, 19a to 19c as the rotor 20 rotates, and calculating the current value. It is calculated by

[0004]

[Problems to be solved by the device]

 In the conventional rotation detecting device, a sine wave voltage of a predetermined voltage is applied from a three-phase oscillator to salient poles provided on each magnetic body, and coils for detecting changes in current value due to rotation of the rotor are respectively provided. Since the coils are wound, the coil requires a required space, which causes an increase in size of the device, which poses a serious obstacle in downsizing the rotation detection device. In addition, a large number of man-hours are required for winding the coil and the number of parts is increased, which causes a problem of high cost.

The present invention has been made in order to solve such a problem, and provides a rotation detecting device capable of miniaturizing the device by effectively utilizing a magnetic sensor to eliminate the coil. The purpose is to provide.

[0006]

[Means for Solving the Problems]

 The present invention is a rotation detecting device that detects rotation and outputs a predetermined electric signal. The first and second gear plates having salient poles protruding from the outer circumference at a constant pitch are coaxially provided. A rotor that rotates with a magnet interposed between both gear plates and a protrusion that faces the outer circumference of the salient poles of the rotor are formed, and gaps are provided concentrically with the rotor. It is characterized by comprising a plurality of stators and a magnetic sensor arranged in the gap of the stator to detect the changing magnetic field.

[0007]

[Action]

 The salient poles projectingly formed on the first and second gear plates of the rotor and the salient poles formed on the plurality of stators are opposed to each other, and the stator is provided with a gap on each concentric circle with the rotor. When the magnetic sensor is placed in this gap, the relative distance between the salient pole and the salient changes due to the rotation of the rotor, so an alternating magnetic field is applied to the magnetic sensor in the gap. An electric signal proportional to the rotation is detected directly from the sensor. Therefore, the space for installing the coil is not required unlike the conventional case, and the rotation detecting device can be easily miniaturized. Further, since the coil winding work is unnecessary, the number of winding steps and the number of parts are reduced, and the cost is reduced.

[0008]

【Example】

 An embodiment of the rotation detecting device according to the present invention will be described below with reference to the drawings. 1 to 3, a rotor 1 has a first gear plate 2 and a second gear plate 3 which are coaxially fitted to an input shaft 4 and is provided between the first and second gear plates 2 and 3. The magnet 5 is interposed between the two. The first and second gear plates 2 and 3 are made of a magnetic material such as iron, and a plurality of salient poles 2a and 3a are formed on the outer periphery thereof in a radial direction so as to project at equal angles. Further, the magnet 5 is formed in a disc shape, and the NS pole is magnetized in the axial direction, and the upper and lower end surfaces thereof are joined to the inner surfaces of the first and second gear plates 2 and 3. Further, the salient poles 2a and 3a of the first and second gear plates 2 and 3 are arranged so as to be displaced from each other by ½ pitch in the circumferential direction and have a phase of 180 degrees in electrical angle. The number of salient poles 2a and 3a of these gear plates 2 and 3 corresponds to the number of poles in the resolver.

On the outer circumference of the plurality of salient poles 2 a, 3 a of the rotor 1, four protrusions 6 a, 7 a, formed on the four stators 6, 7, 8, 9 made of magnetic material such as iron, 8a and 9a face each other. These stators 6 to 9 are arranged concentrically with the rotor 1, and gaps 6b, 7b, 8b and 9b are provided between the respective stators. The protrusions 6a to 9a of the stators 6 to 9 are formed at the same pitch as that of the salient poles 2a and 3a, respectively, and the distance between the stators 6 and 7 and the distance between the stators 8 and 9 are each 180 degrees. The stators 6 and 7 and the stators 8 and 9 are arranged with a phase of 90 degrees with respect to each other.

Further, the end faces of the stators 6 and 7 and the stators 8 and 9 facing the gaps 6b and 8b are formed in a substantially pyramid shape as shown in FIG. The magnetic path is narrowed. The magnetic sensors H1 and H2, which are Hall elements, are disposed inside the gaps 6b and 8b. When the magnetic path of the gap portion where the end faces of the two stators face each other is narrowed in this way, the magnetic flux passing through the gaps 6b and 8b is concentrated, and the magnetic field applied to the magnetic sensor H1 becomes strong, and the output of the magnetic sensor H1 is increased. This is preferable because the signal can be increased. The gaps 7b and 9b are preferably as wide as possible in order to prevent the stator 6 and the stator 9 and the stator 7 and the stator 8 from magnetically affecting each other.

In the rotation detecting device configured as described above, the salient poles 2a and 3a of the first and second gear plates 2 and 3 and the salient portions 6a and 7a of the two stators 6 and 7 are now illustrated. 4A, the magnetic flux generated from the N pole of the magnet 5 passes through the salient pole 2a from the first gear plate 2 as shown by the arrow, and the salient 6a of the facing stator 6 faces. Leading to. Then, the magnetic flux that has passed through the stator 6 is guided to the magnetic sensor H1 and then passes through the protrusion 7a via the stator 7 and reaches the salient pole 3a of the second gear plate 3 that faces the magnetic pole. Further, a magnetic circuit returning to the S pole of the magnet 5 via the second gear plate 3 is formed.

Next, when the first and second gear plates 2 and 3 of the rotor 1 rotate, as shown in FIG. 4B, the salient poles of the first and second gear plates 2 and 3 are formed. Since the facing positions of 2a, 3a and the projecting portions 6a, 7a of the two stators 6, 7 are changed, and the direction of the magnetic flux indicated by the arrow is changed in the opposite direction, the magnetic sensor H1 is shown in FIG. The opposite magnetic flux is applied. The flow of magnetic flux has been described by taking the first and second gear plates 2 and 3 and the two stators 6 and 7 as an example, but the same applies between the gear plates 2 and 3 and the stators 8 and 9. Magnetic flux flows, and the magnetic flux is similarly applied to the magnetic sensor H2.

FIGS. 5A and 5B show changes in the magnetic field applied to the magnetic sensors H1 and H2 as the rotor 1 rotates and output signals of the magnetic sensors H1 and H2. That is, in the figure, the solid line indicates the magnetic sensor H1, and the dotted line indicates the magnetic sensor H2. The alternating magnetic fields are applied to the magnetic sensors H1 and H2 with a phase difference of 90 degrees as shown in FIG. 5 (A). It With such an alternating magnetic field, the output signals shown in FIG. 5B can be obtained from the magnetic sensors H1 and H2.

The above-described embodiment is merely an example, and the number of salient poles of the first and second gear plates and the number of salient poles of the stator are not limited to the above-described example. You may change it to a suitable number. Further, as the magnetic sensor, a magnetoresistive element may be used instead of the Hall element, and other individual configurations can be variously modified without departing from the scope of the present invention.

[0015]

[Effect of device]

 As is apparent from the above description, in the rotation detecting device of the present invention, the salient poles projectingly formed on the first and second gear plates of the rotor and the salient poles respectively formed on the plurality of stators are opposed to each other. , The stator is arranged concentrically with the rotor with a gap, and the magnetic sensor is arranged in this gap. Therefore, the rotation of the rotor causes the magnetic sensor in the gap to be proportional to the rotation of the rotor. The electrical signal generated can be directly detected. Therefore, the coil like the conventional resolver is not required, and the rotation detecting device can be downsized. Further, since the work of winding the coil is not necessary, the winding man-hour is not necessary, and further, the number of parts is reduced, so that the cost is reduced.

[0016]

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of a rotation detecting device according to the present invention.

FIG. 2 is a partial cross-sectional side view showing the above rotation detection device.

FIG. 3 is a side view showing the above rotation detection device.

FIG. 4 is an explanatory diagram showing a flow of magnetic flux of the rotation detection device of the above.

FIG. 5 is a characteristic diagram showing an alternating magnetic field applied to a magnetic sensor and an output.

FIG. 6 is a configuration diagram showing a resolver as a conventional rotation detecting device.

[Explanation of symbols]

 1 rotor 2 1st gear plate 2a salient pole 3 2nd gear plate 3a salient pole 4 input shaft 5 magnet 6-9 stator 6a-9a protrusion 6a-9a gap H1, H2 magnetic sensor

Claims (1)

[Scope of utility model registration request] 1. A rotation detecting device for detecting rotation and outputting a predetermined electric signal, wherein first and second gear plates having salient poles projectingly formed at a constant pitch on the outer periphery thereof are coaxially provided, and both gears are provided. A rotor that rotates with a magnet interposed between the plates and a plurality of protrusions that face the outer circumference of the salient poles of the rotor are formed, and a plurality of rotors are provided on the concentric circles with gaps. A rotation detecting device comprising a stator and a magnetic sensor arranged in the gap of the stator to detect a changing magnetic field.