JPH02176416A - Coupling structure of motor and encoder - Google Patents

Abstract

PURPOSE:To obtain a coupling structure which can display sealing effect with soft coupling and can prevent intrusion of dust and the like by inserting one shaft into the inside of another shaft, and providing a sealing member having a specified sliding structure between both shafts. CONSTITUTION:O rings 32 and 34 are coupled into ring shaped grooves 31 and 33 in the motor shaft 12 that is part protruded from a main body case 20. An encoder shaft 30 is provided at the outside of the rings. Angles are adjusted so that two projections 40 and 36 of shafts 12 and 30 are arranged at every 90 deg.. The positions in the axial direction are adjusted so that the end surfaces of both projections 36 and 40 are aligned on the same plane. Under this state, an annular plate spring 44 is applied on the end surfaces of four projections 36 and 44. The spring 44 is fixed to the shafts 12 and 30 with four bolts. At the same time, a step 18 which is provided at the periphery of an encoder case 16 is coupled with an outer end 22 of the case 20. The cases 16 and 20 are fixed with bolts. The corner of the end 22 is chamfered. An O ring 24 is provided at the step part 18 as a sealing member. Therefore, the desirable structure wherein one shaft is slid on the inner surface of the shaft 30 is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to the structure of a coupling that connects a motor and a rotary encoder that detects the rotation angle of the motor.

[Prior Art] In modern machines operated by motors, accurate positioning is often an important control item.

For this reason, a rotary encoder is connected to the rotor of the motor, and the relative or absolute rotation angle of the rotor is detected by this encoder.

If the motor and encoder are completely rigidly connected with bolts or the like, the following problem will occur. First, since the encoder is a precision machine, if rotor misalignment or vibration during motor operation is transmitted to the encoder, it may cause malfunction or failure. Second, it is difficult to tighten the motor and encoder so that their centers of rotation completely coincide, and if a slight misalignment remains during tightening, an unreasonable load will be placed on the motor or encoder. It took a while,
There is a possibility of damaging any of them.

The third problem is that if the motor repeatedly starts and stops suddenly, rigid connections such as bolts may break due to fatigue.

In order to avoid such problems, various proposals have been made regarding the force coupling structure between the motor and the encoder. Japanese Utility Model Publication No. 56-166517 discloses a structure using a disk-shaped elastic body in order to allow some inclination between the encoder body and the motor mounting plate. Furthermore, Japanese Patent Application Laid-open No. 59-19809 discloses a coupling structure in which a motor rotation shaft and an encoder rotation shaft are coupled by a taper, and a motor body and an encoder body are coupled by a ring-shaped leaf spring. There is. Further, Japanese Utility Model Application Publication No. 61-157820 discloses an example in which the motor body and the encoder body are connected by a corrugated thin plate spring.

[Problem to be solved by the invention] For example, when the motor and encoder are used in a harsh environment where coolant and chips are scattered, such as on a machining line, it is necessary to seal the two bodies together. It is necessary to prevent dust from entering the inside of the casing. In addition, there are cases in which it is desired to rigidly connect the motor and encoder bodies to each other due to problems such as attachment to equipment. As described above, all of the above conventional techniques cannot be used in such cases because the motor body and the encoder body are connected in a flexible manner, and the motor shaft and the encoder shaft are connected in a rigid manner.

Therefore, there is a need for a structure that can provide a flexible connection between the motor shaft and the encoder shaft while also providing a complete seal between them.

[Means for Solving the Problems] The present invention, which has been made to solve these problems, has the following features:
The coupling structure that connects a motor and an encoder that detects the rotation of the motor has the following features. That is, the rotating shaft of either the motor or the encoder is made to protrude outward from the main body of the apparatus, an annular groove is provided on the outer periphery of the protruding shaft, and a sealing member is disposed inside the groove. Then, by fitting the hollow rotary shaft of the other device to the outside of the protruding shaft, both rotary shafts are sealed by the sealing member and the inner peripheral surface of the hollow shaft.

[Operation] For example, if the rotary shaft of the motor is made to protrude outward from the motor body, the encoder shaft is fitted onto the outside of the protruding portion of the motor shaft. Since the space between the two shafts is sealed by a sealing member (such as an O-ring) disposed in the annular groove, there is no fear that dust or the like will enter the inside of the unit through the gap between the two shafts. Also, even if the motor shaft and encoder shaft vibrate in the axial direction,
Since the seal member slides on the inner circumferential surface of the encoder shaft, its movement is not hindered, and the flexible coupling between the two shafts is maintained.

[Example code] An embodiment of the present invention will be explained with reference to FIG. 1.2.

In this embodiment, a shaft 12 protrudes from the main body of the motor 10, and the rotary encoder 14 is attached so as to cover the circumference of the protruding motor shaft 12.

The hollow motor shaft 12 is connected to the main body case 2 of the motor 10.
It protrudes outward from 0 (to the right in Figure 1).

Two annular grooves 3L33 for accommodating seal members are provided in parallel to each other on the outer surface of the protrusion of the motor shaft 12. Further, two protrusions 36 protruding in the axial direction are provided at the right end in FIG. 1 at a distance of 18° from each other.
A bolt hole 38 is provided in each end face of the tip.

The encoder 14 has a hollow shaft 3 inside its case 16.
0, and the shaft 30 is supported within the case 16 by two bearings 17. The end of the encoder shaft 30 also has two protrusions 4° that protrude in the inner diameter direction.
They are provided 80 degrees apart, and each bolt hole 42 is provided on the end face.
will be provided. Although there is a hole in the right end of the encoder case 16 in FIG. 1, a sealing material is provided between the periphery of the hole and the end of the encoder shirt 30 to prevent dust from entering the encoder. prevents intrusion.

The method of coupling the motor and encoder is as follows. Annular groove 3L of the protrusion of the motor shaft 12 from the motor body
After fitting the O-rings 32 and 34 into the O-rings 33 and 33, the encoder shaft 30 is fitted onto the outside thereof. Then, the two protrusions 40 of the encoder shaft 30 and the motor shaft 12
(Fig. 2), and adjust the axial position so that the end surfaces of both protrusions 36 and 40 are on the same plane. do. In this state, apply the annular leaf spring 44 to the end faces of the four protrusions 36 and 40, and attach the leaf spring 44 to both shafts 1 with four bolts.
Fixed at 2.30. At this time, all bolts are in the same direction (
Since it can be installed from the right side in Figure 1), installation and maintenance are easy.

At the same time, the step 18 provided around the encoder case 16 is fitted with the outer peripheral edge 22 of the case 20 of the motor 10, and both cases 16 and 20 are fixed with bolts (not shown). The corners of the outer peripheral edge 22 of the motor case 20 are chamfered, and the fitting stepped portion 18 is provided with an O-ring 24 as a sealing member.
is inserted.

In this way, the cases of the motor 10 and the encoder 14 are rigidly connected by bolts, while the motor shaft 1
2 is coupled to the encoder shaft 30 via an annular leaf spring 44. Since the annular leaf spring 44 has high rigidity in the circumferential direction, the rotation of the motor shaft 12 is transmitted to the encoder shaft 30 without delay. A rotor 46 is attached to the encoder shaft 30, and the absolute or relative rotation angle of the motor IO is electro-optically detected by the rotor 46 and a stator 48 attached to the encoder 140 case 16.

On the other hand, since the annular leaf spring 44 has elasticity in the direction perpendicular to the plane, even if the motor shaft 12 vibrates in the axial direction (left and right direction in FIG. 1), the vibration is absorbed by the leaf spring 44 and the encoder It is not directly transmitted to the shaft 30. Therefore, accurate operation of the encoder 14 is guaranteed, and durability is also improved. At this time, the O-rings 32 and 34 fitted into the annular structure 3L33 of the motor shaft 12 slide on the inner circumferential surface of the encoder shaft 30, so that a sealing effect can be exerted regardless of the axial vibration of these shafts. .

Furthermore, since the O-ring 24 is also inserted between the two cases 16 and 20, water, dust, etc. do not enter the motor lO or the encoder 14 from the joint between the two cases 16 and 20, and the shaft Together with the O-rings 32 and 34 between them, the dustproof properties of this unit are ensured.

[Effects of the Invention] In the present invention, one shaft is inserted into the other hollow shaft, and a sealing member is inserted between the two, so that dust and the like do not enter into the inside of the motor and encoder. There is no fear of it happening. Moreover, since this seal member is structured to slide on the inner circumferential surface of the hollow shaft, movement of both shafts in the axial direction is permitted. This prevents the vibrations of the motor shaft from being directly transmitted to the encoder shaft, increasing the reliability of both devices.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the motor/encoder joint, and FIG. 2 is a front view of the joint. lO...Motor, 12...Motor shaft,
14...Encoder, 30...Encoder shaft, 36.40...Protrusion, 44...Annular leaf spring Fig. 1 Fig. 2

Claims (1)

[Claims] A coupling structure that couples a motor and an encoder that detects the rotation of the motor, in which the rotating shaft of either the motor or the encoder is protruded outside the main body of the device, and the outer periphery of the protruding shaft is By providing an annular groove and arranging a sealing member inside the groove, and inserting a hollow rotary shaft of the other device onto the outside of the protruding shaft, the sealing member and the inner circumferential surface of the hollow shaft are connected to each other. A coupling structure between a motor and an encoder that is characterized by sealing between rotating shafts.