JPH0538525U - Magnetic rotary encoder - Google Patents

Abstract

(57) [Abstract] [Purpose] To construct a magnetic rotary encoder with high accuracy, excellent environmental resistance, and a simple and robust structure at low cost. [Structure] A magnet 1 and plate members 3 ₁ and 3 ₂ that are fixed to a rotary shaft 2 and that face the axial direction at predetermined positions in the radial direction of the rotary shaft 2 and that generate a magnetic field in the axial direction, and a support that supports the rotary shaft 2. disposed member 5, plate 3 _1, 3 provided with the magnetic sensor ₆₁ through ₃ for detecting the movement of the magnetic field based on the _second rotation.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a magnetic rotary encoder that detects a rotation angle of a rotary shaft of an AC servo motor used as a drive source of various FA (factory automation) devices and a magnetic pole position of a rotor.

[0002]

[Prior Art]

 Conventionally, there have been the following detectors for detecting displacements such as a rotation angle of a rotary shaft of an AC servo motor or the like and a magnetic pole position of a rotor. (1) Resolver: When an AC voltage is applied, the output voltage is induced by the principle of a transformer. Since the output voltage changes depending on the rotation angle of the motor, etc., the change in the output voltage is detected.

(2) Optical rotary encoder: A light emitter and a light receiver are provided so as to face a slit formed on a disk-shaped glass substrate attached to a rotary shaft of a motor or the like, and whether or not there is light passing through the slit. To detect. (3) Magnetic rotary encoder: A magnetic resistance element detects whether or not a disk-shaped magnetic recording medium attached to a rotating shaft of a motor or the like is magnetized. (4) Hall element: Detects the leakage magnetic flux of the rotor in the motor. (5) Optical or magnetic absolute encoder: Detects the absolute position of rotation of the motor, etc. by an optical method or a magnetic method, respectively.

[0004]

[Problems to be solved by the device]

 By the way, the various conventional detectors described above have the following drawbacks. Resolvers are robust in construction but complex in processing the detected output voltage. Further, in the optical rotary encoder, the structure of the disk-shaped glass substrate provided with the slit is complicated, and high precision is required. In addition, the light transmittance of the glass substrate is lowered due to the change in time, so the environment resistance is poor.

Further, also in the magnetic rotary encoder, the structure of the magnetized disk-shaped magnetic recording medium is complicated and accuracy is required. On the other hand, Hall elements have poor detection accuracy. In addition, the optical or magnetic absolute encoder requires a large number of tracks, and thus requires a large mounting space as compared with other encoders. This invention was made under such a background, and provides a magnetic rotary encoder that has excellent environmental resistance, a simple and robust structure, high accuracy, and can be configured at low cost. The purpose is to do.

[0006]

[Means for Solving the Problems]

 A magnetic rotary encoder according to the present invention is fixed to a rotating shaft, axially opposed at a predetermined position in the radial direction of the rotating shaft, magnetic field generating means for generating a magnetic field in the axial direction, and a supporting member supporting the rotating shaft. And detecting means for detecting the movement of the magnetic field based on the rotation of the magnetic field generating means.

[0007]

[Action]

 According to the above configuration, when the rotary shaft is rotationally driven, the magnetic field generating means rotates accordingly, so that the detecting means detects the movement of the magnetic field based on the rotation of the magnetic field generating means.

[0008]

【Example】

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a top view showing the configuration of a magnetic rotary encoder according to a first embodiment of the present invention, FIG. 2 is a front view of the magnetic rotary encoder, and FIG. 3 is a schematic perspective view of the same part. In these figures, reference numeral 1 denotes a cylindrical magnet fitted to the rotary shaft 2 and is made of ferrite, rare earth magnetic material, plastic magnet or the like. 3 ₁ and 3 ₂ are butterfly-wing-shaped plate members made of a soft magnetic material such as iron, which are point-symmetric with respect to the rotating shaft 2, and are attached to both end surfaces of the magnet 1.

Reference numeral 4 denotes a printed circuit board having a U-shaped cutout 4a (see FIG. 4), which is arranged on the support member 5 at positions equidistant from the plate 3 ₁ and the plate 3 _{2 in the} axial direction. ing. The printed circuit board 4, as shown in FIG. 5, there from the axial center of the rotation shaft 2 in this distance, the position forming the 120 ° angle to each other with respect to the axial center, the magnet 1, plate 3 ₁ and plate 3 ₂ magnetic field formed by the magnetic sensor ₆₁ through ₃ for detecting the movement (see FIG. 3) is provided. These magnetic sensors ₆₁ through 65 _3, example, constituted by a magnetoresistive element or a Hall element.

In such a configuration, when the rotary shaft 2 is rotationally driven by an AC servomotor (not shown), the plate members 3 ₁ and 3 ₂ are rotated accordingly. Accordingly, the magnetic sensor ₆₁ through ₃ detects the magnet 1 shown in Figure 3, respectively, the plate material 3 ₁ and plate 3 ₂ and a portion b is not part a and the magnetic field is parallel magnetic field formed by alternately At 360 ° of one rotation, the magnetic sensor 6 ₁ outputs the signal S _U shown in FIG. 6 (a), the magnetic sensor 6 ₂ outputs the signal S _V shown in FIG. 6 (b), and the magnetic sensor 6 ₃ Figure 6 (c) outputting a indicates to signal S _W.

As can be seen from FIG. 6, the signal S_VIs the signal S_U60 ° out of phase with the signal S _W Is the signal S_VThe phase is shifted by 60 °. Therefore, the magnetic sensor 6₁~ 6₃ Are arranged corresponding to the magnetic pole positions of the rotor of the AC servomotor (not shown) connected to the rotary shaft 2, so that these signals S_U, S_V, S_WThe magnetic pole position of the rotor of the AC servo motor can be detected based on

Next, a second embodiment of the present invention will be described. FIG. 7 is a schematic perspective view showing the structure of the main part of a magnetic rotary encoder according to the second embodiment of the present invention. In the second embodiment, the magnet 1 and the plate member 3₁And plate material 3₂Instead of the fan-shaped magnet 7 magnetized in the plate thickness direction.₁~ 7_FourTo provide. In addition, these magnets 7 ₁ ~ 7_FourMay be adhered to the side surface of the support member, which has the same shape as the magnet 1 of the first embodiment described above and which is fitted to the rotating shaft 2, by an adhesive or the like. Further, the operation in such a configuration is similar to that of the first embodiment, and therefore its explanation is omitted.

The detection accuracy in the above-mentioned embodiment depends on the shapes of the plate members 3 ₁ and 3 ₂ , but the detection accuracy of the detector for detecting the leakage magnetic flux of the rotor in the motor using the above-mentioned conventional Hall element. Is ± 2 ° to 3 ° in mechanical angle, but ± 0.1 ° in terms of mechanical angle, which is one digit higher accuracy.

[0014]

[Effect of the device]

 As described above, according to the present invention, there is an effect that a magnetic rotary encoder having excellent environment resistance, a simple and robust structure can be configured. Further, there is an effect that it can be configured with high accuracy and at low cost.

[Brief description of drawings]

FIG. 1 is a top view showing a configuration of a magnetic rotary encoder according to a first embodiment of the present invention.

FIG. 2 is a front view showing the configuration of the magnetic rotary encoder according to the first embodiment of the present invention.

FIG. 3 is a perspective view showing a configuration of a main part of the magnetic rotary encoder according to the first embodiment of the present invention.

FIG. 4 is a perspective view showing an example of a configuration of a printed circuit board 4.

FIG. 5 is an explanatory diagram showing an example of an arrangement of magnetic sensors 6 _{1 to} 6 ₃ .

FIG. 6 is a diagram showing an example of waveforms of output signals of magnetic sensors 6 _{1 to} 6 ₃ .

FIG. 7 is a perspective view showing a configuration of a main part of a magnetic rotary encoder according to a second embodiment of the present invention.

[Explanation of symbols]

1, 7 _{1 to} 7 ₄ ...... Magnet, 2 …… Rotation axis 3 ₁ , 3 ₂
…… Plate material, 4 …… Printed circuit board, 5 …… Supporting member, 6 ₁
~ 6 ₃ ...... Magnetic sensor.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Nanayuki Takeuchi 10-1 Nakazawacho, Hamamatsu City, Shizuoka Prefecture Yamaha Stock Company

Claims (1)

[Scope of utility model registration request] 1. A magnetic field generating means that is fixed to a rotary shaft, faces the axial direction at a predetermined position in the radial direction of the rotary shaft, and generates a magnetic field in the axial direction, and a support member that supports the rotary shaft. And a detection means for detecting the movement of the magnetic field based on the rotation of the magnetic field generation means.