JP2629921B2 - Coupling structure between motor and encoder - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a coupling structure for connecting a motor and a rotary encoder for detecting a rotation angle and the like of the motor.

[Related Art] In recent machines operated by a motor, accurate positioning is often an important control item. Therefore, a rotary encoder is connected to the rotor of the motor, and the relative or absolute rotation angle of the rotor is detected by the encoder.

If the motor and the encoder are completely rigidly connected with bolts or the like, the following problem occurs. One is that since the encoder is a precision machine, if the displacement or vibration of the rotor during the operation of the motor is transmitted to the encoder, malfunction or failure may occur. Second, it is difficult to assemble the motor and the encoder so that the rotation centers of the motor and the encoder are completely coincident. If a slight misalignment remains during the assembling, an excessive load is applied to the motor or the encoder. One of them could be damaging. A third problem is that if the motor repeatedly starts and stops suddenly, the rigid connection of the bolts may cause breakage due to fatigue.

In order to avoid such a problem, various proposals have conventionally been made regarding a coupling structure between a motor and an encoder. Japanese Utility Model Application Laid-Open No. 56-166517 discloses a structure using a disc-shaped elastic body in order to allow a slight inclination between the encoder body and the motor mounting board. JP-A-59-19809 discloses a coupling structure in which a motor rotation shaft and an encoder rotation shaft are connected by a taper, and a motor body and an encoder body are connected by a ring-shaped leaf spring. I have. Furthermore, Akira Kai
Japanese Patent Application Laid-Open No. 61-157820 discloses an example in which a motor body and an encoder body are connected by a corrugated thin plate spring.

[Problems to be Solved by the Invention] For example, when a motor and an encoder are used in a poor environment in which a coolant, chips, and the like are scattered, such as in a machining line, both main bodies are integrally sealed. It is necessary to prevent dust from entering the inside of the casing. In addition, there is a case where it is desired that the main body of the motor and the encoder be rigidly connected to each other due to a problem of attachment to the device. In any of the above-mentioned conventional techniques, the motor main body and the encoder main body are softly coupled and the motor shaft and the encoder shaft are rigidly coupled as described above, and thus cannot be used in such a case.

Therefore, there is a need for a structure capable of completely sealing the motor shaft and the encoder shaft while making the motor shaft and the encoder shaft flexible.

Means for Solving the Problems The invention made to solve such problems is a coupling structure for connecting a motor and an encoder for detecting the rotation of the motor, and comprises: The rotating shaft of one of the devices is formed so as to protrude outside the device main body, the rotating shaft of the other device is formed in a hollow shape, and the latter rotating shaft is provided on the projecting side of the former rotating shaft. An annular seal member is provided between the hollow rotary shaft and the protruding rotary shaft for sealing between the rotary shafts. Further, the rotational directions of the rotary shafts are rigidly connected, The two rotating shafts are connected to each other by a connecting means for making a flexible connection. When remote is protruded outwardly, the encoder shaft is inserted into the protruding side of the motor shaft. Since the space between the two shafts is sealed by an annular seal member (for example, an O-ring), there is no possibility that dust or the like may enter the inside of the unit from a gap between the two shafts. In addition, since the rotation directions of both shafts are rigidly connected by the coupling means, the rotation of the motor shaft is transmitted to the encoder shaft without delay, and the axial directions of both rotary shafts are softly coupled. Axial vibration generated between the two shafts is absorbed. In this way, even if the motor shaft and the encoder shaft vibrate in the axial direction, the seal member slides on the inner peripheral surface of the encoder shaft, so that the movement is not hindered and the soft coupling between the two shafts is maintained. Is done.

Embodiment An embodiment of the present invention will be described with reference to FIGS. In the present embodiment, the shaft 12 protrudes from the motor 10 main body,
Both are attached so that the periphery of the protruding motor shaft 12 is covered by the rotary encoder 14.

The hollow motor shaft 12 protrudes outward (to the right in FIG. 1) from the main body case 20 of the motor 10. On the outer surface of the protruding portion of the motor shaft 12, two annular grooves 31, 33 for accommodating a seal member are provided in parallel with each other. Also, two projections projecting in the axial direction are provided at the right end of FIG.
36 are provided 180 ° apart from each other, and bolt holes 38 are provided in the end faces of the tips.

The encoder 14 has a hollow shaft 30 in its case 16, and the shaft 30 is
Supported within. At the end of the encoder shaft 30, two protrusions 40 projecting in the inner diameter direction are provided at a distance of 180 ° from each other. Although a hole is formed in the right end of the encoder case 16 in FIG.
A seal material is provided between the end portions of the encoder to prevent dust and the like from entering the inside of the encoder.

The method of coupling the motor and the encoder is as follows. An annular groove 31 of a protruding portion of the motor shaft 12 from the motor body,
After the O-rings 32 and 34 have been fitted to 33, respectively, the encoder shaft 30 is inserted outside thereof. Then, two projections 40 of the encoder shaft 30 and two projections 36 of the motor shaft 12
Are adjusted so that they are arranged at an angle of 90 ° to each other (FIG. 2), and the axial position is adjusted so that the end faces of both projections 36 and 40 are on the same plane. Four projections in this state
An annular leaf spring 44 is applied to the end faces of 36 and 40, and the leaf spring 44 is fixed to both shafts 12 and 30 with four bolts. At this time, since all bolts can be attached from the same direction (the right side in FIG. 1), attachment, maintenance and the like are easy.

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

As described above, the case of the motor 10 and the case of the encoder 14 are rigidly connected by the bolt, while the motor shaft 12 is connected to the encoder shaft 30 via the 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. Rotor for encoder shaft 30
46 is attached, and the case of encoder 14
The absolute or relative rotation angle of the motor 10 is electro-optically detected by the stator 48 attached to the 16. On the other hand, since the annular leaf spring 44 has elasticity in a direction perpendicular to the plane, even if the motor shaft 12 vibrates in the axial direction (the left-right direction in FIG. 1), the vibration is absorbed by the leaf spring 44 and It is not transmitted directly to the shaft 30. Therefore, while the correct operation of the encoder 14 is guaranteed,
Durability also improves. At this time, since the O-rings 32 and 34 fitted in the annular grooves 31 and 33 of the motor shaft 12 slide on the inner peripheral surface of the encoder shaft 30, the sealing effect is exerted regardless of the axial vibration of these shafts. Can be.

In addition, since the O-ring 24 is interposed between the two cases 16 and 20, water, dust, etc., do not enter the motor 10 or the encoder 14 from the joint between the two cases 16 and 20. In combination with the O-rings 32 and 34 between them, the dustproofness of this unit is ensured.

[Effects of the Invention] In the present invention, one shaft is inserted into the other hollow shaft and a seal member is inserted between the two shafts, so that dust or the like may enter the motor and encoder unit. There is no. In addition, the rotation direction of both shafts is rigidly coupled and the axial direction of both shafts is flexible coupling by the coupling means, so that the rotation of one shaft can be reliably transmitted to the other shaft, and between the two shafts. Can absorb the vibration in the axial direction. In addition, since the seal member has a structure that slides on the inner peripheral surface of the hollow shaft,
It does not hinder the axial movement of both shafts.

Therefore, according to the present invention, the vibration of the motor shaft is not directly transmitted to the encoder shaft, or an unreasonable load is applied between the two shafts due to an axial displacement between the two shafts. And the reliability of both devices can be improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a motor / encoder coupling portion, and FIG. 2 is a front view of the coupling portion. 10 ... Motor, 12 ... Motor shaft, 14 ... Encoder, 30 ... Encoder shaft, 36, 40 ... Protrusion, 44 ...
… Annular leaf spring

Claims (1)

(57) [Claims] 1. A coupling structure for coupling a motor and an encoder for detecting rotation of the motor, wherein a rotating shaft of one of the motor and the encoder projects outside the apparatus main body. Forming the rotating shaft of the other device into a hollow shape, inserting the latter rotating shaft into the projecting side of the former rotating shaft, and inserting the latter between the hollow rotating shaft and the protruding rotating shaft. An annular seal member for sealing between the two rotating shafts is provided.Furthermore, both rotating shafts are connected to each other by coupling means for making the rotational directions of the both rotational shafts rigid and for the axial direction to be softly coupled. A coupling structure between the motor and the encoder.