JP2007255970A - Encoder device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an encoder device of wide application temperature range capable of inhibiting temperature rise of the device itself. <P>SOLUTION: The fins 10 are provided under the disk fixing part 9 of the shaft 7. The rotor, such as servomotor which is not shown is driven, when the shaft 7 is rotated which is connected with the shaft of rotor (not shown), the fins 10 are rotated. As a result, the air in the housing 5 is agitated and the heated air around the substrate 2 is circulated, while the heat is conducted to the housing 5 and and radiated to the outside. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an encoder device used for detecting a rotation angle of a rotating body such as a servo motor.

2. Description of the Related Art Conventionally, there has been disclosed an encoder device that covers the periphery of a rotating disk with a housing, a substrate, etc. and has dust resistance and vibration resistance (see, for example, Patent Document 1).
FIG. 4 is a side sectional view of a conventional encoder device.
In the figure, reference numeral 1 denotes a rotating disk, which is attached to a disk mounting portion 9 formed integrally with the shaft 7 with an adhesive so that it can be rotated integrally with the shaft 7. The shaft 7 is connected to a shaft such as a servo motor (not shown), and is fixed to the housing 5 via a bearing 8. Reference numeral 2 denotes a substrate, which is fixed to the housing 5 with a disc cover 4 provided around the rotary disc 1 interposed therebetween. 3 is a light receiving element, and 6 is a light emitting element, which are arranged at positions facing each other across the rotating disk 1.

Next, the operation will be described.
When a shaft (not shown) such as a servo motor rotates, the shaft 7 connected to the shaft rotates, and the rotating disk 1 bonded to the disk mounting portion 9 of the shaft 7 rotates. The rotating disk 1 is provided with a slit in advance, and when the rotating disk 1 rotates, the light from the light emitting element 6 repeats light shielding and light transmission by the slit. The light transmitted through the slit is received by the light receiving element 3 through the rotating disk 1 and converted into an electric signal. A signal obtained by the light receiving element 3 is converted into an angle signal by a signal processing circuit (not shown) on the substrate 2. The rotational position of a rotating body such as a servo motor is detected from this angle signal.

As described above, the conventional encoder device seals the rotating disk with a housing, a disk cover, a substrate, etc., prevents entry of dust and the like from the outside, and is provided with a disk cover around the rotating disk to provide vibration resistance. Was secured.
JP 2002-350190 A (FIG. 1)

  However, in the conventional encoder device, heat generated by the IC etc. on the substrate and heat from a rotating body such as a servo motor are conducted to the encoder device via the shaft 7, and the temperature in the sealed housing is controlled. Raised. Further, the heat generated by the IC on the substrate is stagnated in the vicinity of the component, which causes a problem that the temperature of the component on the substrate exceeds the operation limit temperature.

  The present invention has been made in view of such problems, and has a wide range of application that can suppress the temperature rise of the encoder device against heat generated by components on the board or heat generated by a rotating body such as a servo motor. An object is to provide an encoder device.

In order to solve the above problems, the present invention is configured as follows.
According to the first aspect of the present invention, there is provided a rotating disk, a shaft that fixes the rotating disk and is connected to the rotating body, a housing that is fixed to the shaft via a bearing, and that accommodates the rotating disk; An encoder apparatus comprising: a fixed substrate; a light emitting element that irradiates the rotating disk; and a light receiving element that is attached to a position facing the light emitting element across the rotating disk, wherein the shaft includes the housing It is characterized by having fins that stir the air inside.
The invention according to claim 2 is characterized in that the fins are provided at three or more locations at equal intervals in a step portion of the shaft mounting portion of the shaft with respect to the shaft.

According to the first aspect of the present invention, since the fin that rotates according to the rotation of the shaft is provided, the air in the housing is agitated, whereby the air around the substrate is circulated, and the temperature rise of the substrate can be reduced. Therefore, it is possible to realize an encoder device that has excellent temperature environment characteristics and a wide application range.
According to the second aspect of the present invention, if the fins are provided at three or more locations, the strength of the disk mounting portion can be increased without increasing the inertia, and the vibration resistance is improved. Further, since the strength of the disk mounting portion is increased, the disk mounting portion can be made thinner, and the encoder device can be downsized.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional view of an encoder apparatus showing a first embodiment of the present invention.
In the figure, reference numeral 1 denotes a rotating disk, which is attached to a disk mounting portion 9 formed integrally with the shaft 7 with an adhesive, so that it can rotate integrally with the shaft 7. The shaft 7 is connected to a shaft such as a servo motor (not shown), and is fixed to the housing 5 via a bearing 8. Reference numeral 2 denotes a substrate on which the light receiving element 3 is mounted and fixed to the housing 5. The light emitting element 6 is disposed at a position facing the light receiving element 3 with the rotating disk 1 interposed therebetween, and is fixed to the housing 5 as a single unit.
Reference numeral 10 denotes a fin, which is attached to the disc attachment portion 9 of the shaft.
FIG. 2 is a plan view of the disk mounting portion showing the arrangement of fins in this embodiment.
The fins 10 are attached to two steps at equal intervals on the step portion of the shaft with respect to the disc attachment portion 9.
Thus, in this invention, it is the structure which provided the fin in the disc attachment part of the shaft.

Next, the operation will be described.
When a rotating body (not shown) such as a servo motor is driven and the shaft 7 rotates, the fin 10 provided on the disk mounting portion 9 of the shaft 7 rotates, so that the air in the housing 5 is agitated. Thus, the air around the substrate 2 having heat is circulated.
Since the operation for detecting the rotational position of the rotating body is the same as in the prior art, the description thereof is omitted.
In the present embodiment, the fin shape is triangular, but it is needless to say that air can be stirred even in a curved shape or a comb shape, and the same effect can be obtained.

  In this way, in this embodiment, since the fins are provided in the disk mounting portion of the shaft, the air in the housing is agitated, and the temperature rise of the substrate can be suppressed. Moreover, since the applicable range with respect to the ambient temperature is expanded, a highly reliable encoder device can be provided.

FIG. 3 is a plan view of the disk mounting portion showing the fin arrangement in the second embodiment of the present invention.
In the figure, the fins 10 are attached at three equal intervals to the step portion of the shaft with respect to the disc attachment portion 9 of the shaft.
This embodiment is different from the first embodiment in that fins are provided at three locations.
In the first embodiment, if the disk mounting portion is greatly vibrated by vibration of the rotating body or the like, the disk mounting portion may be broken. In this embodiment, however, fins are arranged at three locations on the disk mounting portion. By arranging them evenly on the top, the disc mounting portion of the shaft is supported, and vibration is unlikely to occur.

  As described above, in this embodiment, the fins are provided at the three positions of the disk mounting portion, so that the vibration resistance is improved. Further, since the strength of the disk mounting portion has increased, the thickness dimension of the disk mounting portion of the shaft can be reduced, and the encoder device can be miniaturized.

  In the first and second embodiments, the configuration in which the fin is attached to the disc mounting portion is shown. However, it is obvious that the disc mounting portion itself may have a fin portion.

Sectional drawing of the encoder apparatus which shows 1st Example of this invention The top view of the disc attachment part which shows arrangement | positioning of the fin in 1st Example of this invention The top view of the disc attachment part which shows arrangement | positioning of the fin in 2nd Example of this invention Sectional view of a conventional encoder device

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rotating disk 2 Board | substrate 3 Light receiving element 4 Disc cover 5 Housing 6 Light emitting element 7 Shaft 8 Bearing 9 Disk attachment part 10 Fin

Claims (2)

A rotating disk;
A shaft for fixing the rotating disk and connecting to the rotating body;
A housing fixed to the shaft via a bearing and containing the rotating disk;
A substrate fixed to the housing;
A light emitting element for irradiating the rotating disk;
A light receiving element attached at a position facing the light emitting element across the rotating disk;
In an encoder device comprising:
The encoder device according to claim 1, wherein the shaft includes a fin that stirs air in the housing.   The encoder device according to claim 1, wherein the fin is provided at three or more locations at equal intervals in a step portion of the shaft mounting portion of the shaft with respect to the shaft.

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