JP4711412B2 - Magnetic encoder - Google Patents

Description

  The present invention relates to a small-sized magnetic encoder used for, for example, detecting the rotation angle of each joint of an articulated robot, detecting the position of a steering wheel of an automobile, and controlling a brushless DC motor.

  There are two types of encoders: optical and magnetic. Particularly, the optical type includes a housing that rotatably supports a shaft having a rotation slit at the end, and a groove is formed on the outer peripheral surface of the housing. It is formed and an O-ring is fitted. Then, the housing is fitted into the cover from the side of the rotary slit so that the airtightness is maintained (there are no publications describing this prior art).

  However, in the conventional encoder described above, it is necessary to machine a groove in the housing, which requires time for the groove machining, and also requires man-hours for assembling an O-ring. . Further, since the outer peripheral surface of the housing is covered with the cover, it has not been possible to confirm whether the O-ring is incorporated in the groove. Further, as described above, since a groove is required in the housing, the height dimension of the housing is lengthened accordingly, and accordingly, the dimension of the cover is also lengthened, and the height dimension as the encoder is lengthened.

  The present invention has been made to solve the above-described problems, and provides a magnetic encoder that can further reduce the cost by reducing the outer dimensions, ensuring waterproofness without using an O-ring. The purpose is to do.

The magnetic encoder according to the present invention has a magnet fixed to the tip of the shaft and a Hall element that detects a magnetic field change accompanying the rotation of the magnet, and calculates the rotation angle of the shaft based on the detection of the Hall element. In addition, in a magnetic encoder having an arithmetic processing unit that generates a plurality of signals based on the rotation angle information, and a plurality of circuit units that output the plurality of signals generated by the arithmetic processing unit to the outside, It has a magnet and processing unit further includes a encoder main body portion having a housing, and a cover that fits on the housing so as to cover the magnet and arithmetic processing unit for rotatably supporting the shaft, which is connected to the encoder main body portion lead cable, provided on the lead cable, and a relay unit having a power supply for supplying power supply circuit to a plurality of circuit units and the encoder main body, ene It was subjected to sealing material to the outer surface except for the protruding surface of the shaft over da body portion of the cover and the housing.

In the present invention, the magnets and the arithmetic processing unit, to configure the encoder main body portion by a cover which fits on the housing to cover the housing for rotatably supporting the shaft, and a processing unit magnets, the cover of the encoder main body portion Since the seal material is applied to the outer surface of the housing except for the protruding surface of the housing , groove processing and O-ring assembly work are not required, so that waterproofness can be secured and costs can be reduced. Therefore, the height dimension of the encoder main body can be shortened.

FIG. 1 is an external view of a partial cross section showing a magnetic encoder according to an embodiment of the present invention, and FIG. 2 is an external view showing a sealing material applied to an encoder main body of the magnetic encoder.
The magnetic encoder according to the present embodiment includes an encoder main body 10, a lead cable 20 connected to the encoder main body 10, a relay part 30 having one end connected to the lead cable 20, and the other relay part 30. The lead cable 21 is connected to the end. The lead cable 21 is connected to a controller (not shown).

  The encoder main body 10 includes a shaft 11 having a recess 11a formed at the tip, a magnet 12 having a magnetic flux density of, for example, 12 kGs inserted into the recess 11a of the shaft 11, and a recess 13a formed at the upper portion. The seal bearing 13b is arranged in the circumferential direction, the housing 13 that rotatably supports the tip of the shaft 11 by the recess 13a, and the IC chip 14 that is disposed above the magnet 12 and faces the magnet 12 on the lower surface (calculation) The substrate 15 on which the processing unit is mounted, the male connector 16 (first connector) mounted on the upper surface of the substrate 15, and the plurality of strands 20 a of the lead cable 20 are connected to the male connector 16. A female connector 17 (second connector) connected to the housing 13 and a magnetic material cover 18 fitted to the housing 13 are configured. This cover 18 shields the influence of an external magnetic field. The lead cable 20 drawn out from the cover 18 is sealed with a sealing rubber 19.

  The above-mentioned IC chip 14 is centered on the central axis of the shaft 11, and a hall element (not shown) for detecting a magnetic field change accompanying the rotation of the magnet 12 around the center is an interval of 90 degrees. Has been placed. The IC chip 14 calculates the rotation angle of the shaft 11 based on detection of the Hall element, and outputs the absolute data (rotation angle information) in the form of a PWM signal and a digital signal (for serial communication). Generate an incremental signal. As this incremental signal, there are an A phase / B phase signal, a brushless DC motor commutation signal (U phase / V phase / W phase signal), etc., and these signals are switched by setting the signal mode. ing.

  The male connector 16 mounted on the upper surface of the substrate 14 has a plurality of connection pins (not shown) protruding forward on one end face, and from the same end face so as to surround the connection pins from four sides. A rectangular guide portion 16a protruding forward is provided. This guide portion 16a facilitates insertion of the female connector 17. As shown in FIG. 2, a resin sealing material 40 is applied to the outer surfaces of the cover 18 and the housing 13 other than the shaft protruding surface. The seal material 40 is formed by a hot melt method in which the seal body 40 is molded by being inserted into the mold from the cover 18 side of the encoder body 10 and pouring a liquid seal material into the gap with the mold. Since the lead cable 20 drawn from the cover 18 is sealed with the sealing rubber 19, the sealing material does not flow inside.

  For example, the relay unit 30 includes a substrate (not shown) on which a power supply circuit unit, a low-pass filter unit, a communication interface unit, an output circuit, and the like are mounted, and the substrate is protected by a cover. The power supply circuit unit converts the power supply 5V from the controller to a constant voltage and supplies it to the substrate 15 of the encoder body 10. The low-pass filter unit converts the PWM signal into an analog signal. When the communication interface unit receives a request for rotation angle digital data from the controller, the communication interface unit notifies the IC chip 14 to that effect, and when a digital signal (absolute) is received from the IC chip 14 in response to this notification, the controller Transfer (serial) to. The output circuit outputs an incremental signal from the IC chip 14 to the controller.

  As described above, the encoder main body 10 can be freely rotated by the recess 13a with the shaft 11 having the recess 11a formed at the tip, the magnet 12 fitted into the recess 11a of the shaft 11, and the tip 11 of the shaft 11. A housing 13 to be supported, a substrate 15 disposed above the magnet 12 and mounted on the lower surface with the IC chip 14 facing the magnet 12, a male connector 16 mounted on the upper surface of the substrate 15, and a lead cable 20 Since the plurality of strands 20a are connected and the female connector 17 is detachably connected to the male connector 16 and the magnetic material cover 18 fitted to the housing 13, the outer dimensions are 15 mm × 15 mm ×. A small encoder body 10 of 22 mm is obtained, and the cover 18 and the housing 13 (excluding the shaft protruding surface) of the encoder body 10 are obtained. Since the sealing material 40 is applied to the outer surface, groove processing and O-ring assembly work are not required, so that waterproofness can be secured and costs can be reduced, and the height of the groove is not required. Therefore, the height dimension of the encoder main body 10 can be further shortened.

1 is an external view of a partial cross section showing a magnetic encoder according to an embodiment of the present invention. It is an external view which shows the sealing material given to the encoder main-body part of a magnetic encoder.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Encoder main part, 11 Shaft, 11a Recessed part, 12 Magnet, 13 Housing, 13a Recessed part, 13b Seal bearing, 14 IC chip, 15 Substrate, 16 Male connector, 16a Guide part, 17 Female connector, 18 Cover, 19 Seal Retaining rubber, 20, 21 Lead cable, 20a Wire, 30 Relay part.

Claims (2)

A magnet fixed to the tip of the shaft and a Hall element that detects a magnetic field change accompanying the rotation of the magnet, calculates the rotation angle of the shaft based on the detection of the Hall element, and information about the rotation angle In a magnetic encoder having an arithmetic processing unit that generates a plurality of signals based on the above and a plurality of circuit units that output the plurality of signals generated by the arithmetic processing unit to the outside,
Said magnet and having the arithmetic processing unit, further, the encoder body having a cover that fits the shaft rotatably supported to the housing, and the housing so as to cover the operation processing unit and the magnet,
A lead cable connected to the encoder main body portion,
Provided on the lead cable, and a relay unit having a plurality of circuit units and the encoder main body to a power supply source circuit section,
A magnetic encoder, wherein a seal material is provided on an outer surface excluding a cover of the encoder main body and a protruding surface of a shaft of the housing . The encoder body is
A substrate on which the arithmetic processing unit is mounted;
A housing that rotatably supports the shaft so that the magnet faces an arithmetic processing unit on the substrate;
A first connector mounted on the surface opposite to the processing unit mounting surface of the substrate;
A second connector connected to the lead cable and detachably connected to the first connector;
The magnetic encoder according to claim 1, further comprising: a cover that fits into the housing so as to cover the first and second connectors and the substrate.

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