JPS6247518A - Structure for attaching encoder to motor - Google Patents

Abstract

PURPOSE:To make the structure simple and economical, and also to eliminate a detection error of an encoder by fixing a revolving shaft of the encoder to a rotor shaft of a motor, and fixing a housing of the encoder to a stator of the motor through a plate spring. CONSTITUTION:A disk type synchronous motor M is provided with plural discoid stators 11 and plural discoid rotors 12. Each rotor 12 has a nonmagnetic ring 12a to which plural magnets 12b provided in the peripheral direction have been fixed, and the ring 12a is fixed to a sleeve 14, respectively. Also, a rotor shaft is fixed to a hole 15 which has been provided on the sleeve 14, and in the other end side of the sleeve 14, a revolving shaft 18 of an encoder P is fitted and fixed concentrically to its projecting part 20 and a recessed part 19 of the sleeve 14. Also, a housing 22 of the encoder P is fixed to a housing 16 of the motor M through a plate spring 24. Accordingly, even if the rotor shaft which has been fixed to the sleeve 14 is inclined by receiving a force of a load and also the revolving shaft 18 of the encoder P is inclined, the housing 22 of 6the encoder P is also inclined against a force of the plate spring 24, and a large force of the opposite direction is not applied to the revolving shaft 18 of the encoder P and the rotor shaft.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a disc-shaped rotor having a structure in which a rotor is supported relative to a stator by a single bearing that can independently support loads in the axial and radial directions. This invention relates to an encoder mounting structure for a disk-type synchronous motor having a stator and a rotor.

BACKGROUND OF THE INVENTION A permanent magnet type disk-type synchronous motor having a disk-shaped stator and rotor can generate a very large 1-lux, and is often used in a so-called direct drive system. In this system, there is only one bearing on the motor side, and a cross roller bearing that can support both axial and thrust directions is used. This allows for a concise 1
11IR can be obtained. However, even if a highly rigid cross roller bearing or the like is used, the rotor shaft may tilt or move slightly due to the load attached to the rotor shaft. Therefore, attaching an encoder for rotation detection to the shaft end of the rotor shaft,
Since the rotating shaft of the encoder is fixed to the rotor shaft, and the stationary part of the encoder, such as the housing, is fixed to the stator part of the electric motor, a phenomenon occurs in which the rotor shaft and the rotating shaft of the encoder are bent. As a result, there have been drawbacks such as errors occurring in the detection of rotational speed and position to be detected by the encoder. In order to improve this drawback, a method of fixing the encoder using a flexible joint or the like may be considered, but this method would be costly and would not be economical.

Problems to be Solved by the Invention The present invention improves the drawbacks of the above-mentioned prior art and has a simple structure.
A disk-shaped stator with a structure in which the rotor is supported by a bearing alone that can support loads in the axial and radial directions and that is economical and does not cause encoder detection errors, and a disk that has a rotor. The purpose of this invention is to obtain an encoder mounting structure for a type synchronous motor.

Means for Solving the Problems The above problem is solved by rigidly fixing the rotating shaft of the encoder to the rotor shaft of the disc-type synchronous motor, and fixing the housing of the encoder to the stator of the synchronous motor via a leaf spring. Resolved the point.

Even if the rotating shaft of the encoder, which is rigidly fixed to the rotor shaft, tilts or moves due to the force from the load, the stationary part of the encoder also tilts or moves. As the encoder moves, it tilts and moves against the force of the leaf spring, and the entire encoder moves with the tilt of the rotor axis, so there is no possibility of bending the rotor axis or the encoder's rotation axis, and there is no possibility of encoder detection errors. .

Embodiment The figure is a sectional view of a main part of an embodiment of the present invention, where M is a disk-type synchronous motor, and the synchronous motor is equipped with a disk-shaped stay 11 having multiple circumferences and a plurality of disk-shaped rotors 12. . Each disc-shaped rotor 12 has a non-magnetic ring 12a to which a plurality of permanent magnets 12b arranged in the circumferential direction are fixed, and the rings 12a are fixed to the sleeve 14, respectively. The disc-shaped stator 11 and the disc-shaped rotor 12 are arranged alternately in the axial direction with small gaps interposed therebetween. A rotor shaft (not shown) is fixed to the hole 15 provided in the sleeve 14, and the sleeve 14 is connected to the housing 16 of the electric lff1M by a single bearing that supports the loads in the axial and radial directions. In the embodiment, it is rotatably supported by one cross roller bearing 17.

On the other hand, the rotary shaft 18 of the encoder P is rigidly fixed to the other end of the sleeve 14 so as to be concentric and not deviated. In this embodiment, the sleeve 14
The four portions 19 provided at the edges and the convex portions 2Q provided on the end face of the rotary shaft 18 of the encoder P fit together to prevent the axial center from shifting,
It is rigidly fixed by Pol 1-21. On the other hand, the rotary shaft 18 of the encoder P is rotatably fixed to a housing 22, which is a stationary part of the encoder P, by a bearing 23, and the housing 22 of the encoder P is connected to the housing 16 of the synchronous motor via a leaf spring 24. Fixed.

The rotary disk 25 of the encoder is fixed to the rotary shaft 18, rotates together with the rotary shaft 18, and detects the rotation of the rotor shaft using a photoelectric element (not shown) provided in the housing 22. It is.

With the above structure, the rotor shaft is tilted when the rotor shaft is fixed to the sleeve 14 and receives a force such as a load, and furthermore, the rotary shaft 18 of the encoder P fixed to the sleeve 14 is Even if the encoder P is tilted, the inner body of the housing 22 of the encoder P is also tilted against the force of the leaf spring 24, so that a large force in the opposite direction is not applied to the rotary shaft 18 or the rotor shaft of the encoder P, and these shafts are not bent. There isn't.

Effects of the Invention As described above, the present invention provides an encoder for a synchronous motor having a disc-shaped stator and a rotor, which has a structure in which the rotor is supported relative to the stator by a single bearing that can support loads in the axial and radial directions. When installing the encoder, the rotating shaft of the encoder is rigidly fixed to the rotating shaft of the rotor, and the stationary part of the encoder is fixed to the stator part of the electric motor via a leaf spring, so that the rotor shaft and the rotating shaft of the encoder are not tilted. However, the encoder itself does not tilt against the force of the leaf spring, bending the rotor axis or the encoder's rotation axis, and the detection error caused by the encoder can be reduced.

[Brief explanation of drawings]

The figure is a sectional view of a main part of an embodiment of the present invention. DESCRIPTION OF SYMBOLS 11... Disc-shaped data, 12... Disk-shaped rotor, 12a... Ring, 12b... Permanent magnet,
14... Sleeve, 16... Electric 1jll housing, 17... Cross roller bearing, 18... Encoder rotating shaft, 24... Leaf spring, M... Synchronous motor,
P...Encoder.

Claims (2)

[Claims] (1) In a synchronous motor that has a disc-shaped stator and rotor, which has a structure in which the rotor is supported to the stator by a single bearing that can support loads in the axial and radial directions, the rotary shaft of the encoder is attached to the rotor shaft as a rigid body. and a housing of the encoder is fixed to the stator of the synchronous motor via a leaf spring. (2) The encoder mounting structure for an electric motor according to claim 1, wherein the single bearing is a cross roller bearing.