JPH0353175Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a coupling gear for a rotary encoder, and more specifically, a rotation speed detection device (hereinafter referred to as an encoder) comprising a rotating disk and an optical sensor to measure the rotation speed of a rotating body such as a motor. The present invention relates to a coupling gear suitable for use in transmitting rotational motion of a rotating body to an encoder when detecting the rotational motion of a rotating body.

FIG. 1 shows a diagram of the principle of this type of encoder. In the figure, 1 is a rotary motor capable of forward and reverse rotation, 1a is its rotation shaft, 2 is an encoder, and 2a is its rotation shaft. This rotating shaft 2a
are connected inside the casing 2b of the encoder 2, perpendicularly to a rotating disk 2c having a large number of slits (not shown) in the periphery.
Inside the casing 2b, a light emitting element 2d such as a light emitting diode is inserted through a slit in the rotating disk 2c.
A light-receiving element 2e such as a phototransistor is disposed facing each other. Note that the light emitting element 2d is connected to its drive circuit, and the light receiving element 2e is connected to an A/D conversion circuit, a counter, etc., but for convenience, none of these are shown.

In order to detect the rotation speed of the motor rotation shaft 1a by such an encoder 2, the rotation shaft 1a and the rotation shaft 2a of the encoder 2 are connected by an appropriate coupling device 3, and the rotation speed driven by the rotation shaft 1a is connected. A pulse signal corresponding to the number of rotations of the rotating shaft 1a is obtained by an optical sensor consisting of a disk 2c, a light emitting element 2d, and a light receiving element 2e, and is counted.

Conventionally, a belt or a coupling gear has been used as the coupling device 3 for transmitting the rotation of the rotating shaft 1a to the encoder 2. The rotation of the rotating shaft 1a of the motor 1, which rotates or reverses, is not accurately transmitted to the encoder 2 due to the backlash between the pair of gears, causing an error in the pulse signal output from the optical sensor, resulting in an increase in the rotational speed. The drawback was that accurate detection could not be performed. In addition, in order to eliminate this backlash, two gears are provided on either the driving side or the driven side, and the other gear is sandwiched between these gears, but these generally have complicated structures and adjustments. It had some drawbacks.

The present invention was proposed in view of the above points, and its purpose is to make the driving side or driven side gear flexible in a coupling gear that transmits the rotational motion of a rotating body to an encoder. A rotary rotary with a simple configuration that uses a nearly cylindrical transmission gear with a bottom to accurately transmit the rotational motion of the rotating body to the encoder, making it possible to detect the rotational speed without error. The present invention provides a coupling gear for an encoder.

The present invention will be explained below with reference to the drawings.

FIG. 2 shows an embodiment of the present invention. In the figure, 1 is a motor as a rotating body, 1a is its rotating shaft, and the motor 1 is attached to a substrate 4 with screws or the like. Also, near this motor 1,
The encoder 2 rotates its rotation axis 2a to the rotation axis 1a.
It is attached to the board 4 with screws or the like in parallel with the above. Note that inside the casing 2b of the encoder 2, a rotating disk connected to the rotating shaft 2a as in FIG. 1, and an optical sensor consisting of a light emitting element, a light receiving element, etc. are arranged, but these are shown for convenience. Illustrations are omitted.

The rotating shaft 1a of the motor 1 is provided with a transmission gear 5 as shown in FIG. 3, which constitutes a coupling gear.
can be installed. The transmission gear 5 is made of flexible synthetic resin, and has a substantially bottomed cylindrical shape, with the outer periphery of the cylindrical portion being slightly thicker on the outer periphery side than on other parts. , and gear teeth 5a are formed on its outer periphery. Further, a recess 5b is protruded from the center of the bottom surface, and this recess 5
b is a through hole 5c into which the rotating shaft 1a of the motor 1 is inserted.
is penetrated. Note that a screw (not shown) for attaching the transmission gear 5 to the rotating shaft 1a is screwed into a screw hole 5d formed in the recess 5b.

Referring again to FIG. 2, the rotary shaft 2 of the encoder 2
A flat gear 6 made of metal or synthetic resin is attached to a, and this gear 6 is tightly screwed into the teeth 5a of the transmission gear 5. Further, in FIG. 2, numeral 7 indicates a clamp collar, and numeral 8 indicates a cover covering the coupling device according to the present invention.

In this embodiment, the transmission gear 5 is attached to the motor on the drive side, but the present invention is not limited to this. The gear 6 may be attached to the motor 1, and the transmission gear 5 may be attached to the encoder 2 as a driven side. Of course, it is also possible.

As described above, in the present invention, in order to detect the rotational speed of the rotating body, the coupling device includes a pair of gears that connects the rotating body to a rotational speed detection device comprising a rotating disk and an optical sensor. Since one of the transmission gears constituting the is made of a flexible material and formed into a substantially cylindrical shape with a bottom, the transmission gear and the other gear are always in close mesh with each other, and when a rotating body such as a motor rotates in the normal direction. Alternatively, the bump crash that occurs when reversing is completely absorbed by the material of the transmission gear and its flexibility due to its hollow thin structure, and the rotational displacement to be transmitted can be accurately transmitted, and the rotational displacement to be transmitted can be accurately transmitted. This has the effect of accurately detecting the rotational speed of the rotating body without the risk of causing an error in the detected detection signal.

[Brief explanation of drawings]

FIG. 1 is a principle diagram of an encoder, FIG. 2 is a cross-sectional view of a main part showing an embodiment of the present invention, and FIG. 3 is a perspective view of a transmission gear. 1... Motor, 1a... Rotating shaft, 2... Encoder, 2a... Casing, 4... Board, 5...
Transmission gear, 5a...teeth, 5b...protrusion, 5c...
Through hole, 5d... screw hole, 6... gear, 7... clamp collar, 8... cover.

Claims (1)

[Scope of utility model registration request] In order to detect the rotational speed of the rotating body, one of the transmission gears constituting a coupling device consisting of a pair of gears that connects the rotating body to a rotational speed detection device comprising a rotating disk and an optical sensor is flexible. For a rotary encoder, the outer periphery of the cylindrical portion is formed into a substantially bottomed cylindrical shape using a material having the following properties: Cut spring gear.