JP4094575B2 - Rotary encoder mounting apparatus and mounting method - Google Patents

Description

  The present invention relates to an attachment device for connecting a rotary encoder having a hollow shaft at the shaft end of an electric motor, and an attachment method using the device.

An encoder that converts the rotation angle into an electric signal is attached to the shaft end for speed control. As the encoder, there is a rotary encoder provided with a rotatable hollow shaft. A conventional attachment device for attaching this hollow shaft type rotary encoder to an electric motor is shown in FIGS. The illustrated rotary encoder mounting apparatus has the same configuration as that disclosed in Patent Document 1.
First, in FIGS. 9 and 10, the rotary encoder 41 includes a main body and a hollow shaft 42 that passes through the main body and is rotatably attached. In the main body, a light emitting diode, a light receiving element, a rotary slit plate, a fixed slit plate, and the like are housed, and the rotary slit plate is attached to the hollow shaft 42 and rotates. The main body is attached to the motor fixing portion 44 by a support member 43 obtained by bending a plate material.
A relay shaft 45 is connected to the motor shaft 47. The relay shaft 45 is inserted into the hollow shaft 42, and a key 46 is driven between them, and the hollow shaft 42 and the relay shaft 45 are tightened. As a result, the rotation of the electric motor is transmitted to the rotary slit plate, and the rotation angle is converted into an electric signal.

11 and 12 show another example of a conventional rotary encoder mounting apparatus. In the figure, a rotary encoder 51 is composed of a main body and a hollow shaft 52 that is rotatably mounted through the main body. The hollow shaft 52 has a tapered inner surface.
Similarly, a light emitting diode, a light receiving element, a rotary slit plate, a fixed slit plate, and the like are accommodated in the main body, and the rotary slit plate is attached to the hollow shaft 52 and rotates. The main body is attached to the motor fixing portion 44 by a support member 53 obtained by bending a plate material.
A relay shaft 55 formed in a tapered shape corresponding to the hollow shaft 52 is connected to the motor shaft 47. After the relay shaft 55 is inserted into the hollow shaft 52, a bolt 56 is screwed into the relay shaft 55 from the shaft end side, the hollow shaft 52 is pushed in, and both are fitted together. As a result, the rotation of the electric motor is transmitted to the rotary slit plate, and the rotation angle is converted into an electric signal. In this example, since the relay shaft 55 and the hollow shaft 52 are fitted in a tapered shape, the rotation shaft of the hollow shaft 52 can be easily aligned with the rotation shaft of the relay shaft 55.

Japanese Unexamined Patent Publication No. 2003-337051 (paragraph numbers 3-6, FIGS. 3 and 4)

The conventional rotary encoder mounting apparatus is configured as described above. When the relay shafts 45 and 55 are manufactured separately from the motor shaft 47 and then connected to the motor shaft 47, both shaft centers are aligned. In addition, for example, it is necessary to additionally process an uneven fitting portion.
Further, as shown in FIGS. 11 and 12, when the inner surface of the hollow shaft 52 of the rotary encoder is tapered, the relay shaft 55 must be further processed according to the tapered shape.
When the electric motor is in the manufacturing process of the factory, the machining of the electric motor shaft 47 and the relay shafts 45 and 55 is not particularly problematic.
However, when a new rotary encoder is attached to the motor that has already been installed and is in operation, at least the motor shaft 47 must be additionally machined with the connecting shafts 45 and 55 at the installation site. There is a problem that the rotary encoder cannot be attached to the electric motor because the additional processing cannot be performed depending on the installation site of the electric motor.

Further, even if the fitting portion can be additionally processed at the installation site, there is a problem that high-precision processing cannot be performed because the processing equipment that can be carried in is limited.
Further, as shown in FIGS. 11 and 12, when the inner surface of the hollow shaft 52 of the rotary encoder has a tapered shape, the relay shaft 55 must be machined in accordance with the tapered shape. When the relay shaft 55 is integrated with the motor shaft 47, the taper shape processing of the relay shaft 55 is performed at the installation site. It is virtually impossible to perform such processing at the installation site. That is, there is also a problem that the rotary encoder cannot be additionally attached to the existing electric motor due to the shape of the hollow shaft of the rotary encoder.

  The present invention has been made to solve the above-described problems. A rotary encoder can be attached to a shaft end of an existing electric motor by performing a simple additional process. An object of the present invention is to provide a rotary encoder mounting device and a mounting method capable of matching the axis of the encoder with high accuracy.

  A rotary encoder mounting apparatus according to the present invention relates to a rotary encoder having a rotatable hollow shaft, and a screw is threaded on an inner surface of an end portion of a cylindrical relay shaft to be inserted into the hollow shaft. Then, a cylindrical positioning tool whose tip is processed into a conical shape is screwed, and this positioning tool is brought into contact with a center hole formed at the shaft end of the motor with a predetermined dimension exposed from the relay shaft. The relay shaft and the positioning tool are screwed into the center hole through the connecting tool to connect the relay shaft to the shaft end, and then the relay shaft is inserted into the hollow shaft of the rotary encoder, and the fastener is further connected to the relay shaft. And the hollow shaft is fixed to the relay shaft.

  According to another rotary encoder mounting apparatus of the present invention, a cylindrical positioning tool whose tip is processed into a conical shape is inserted into the relay shaft, and a positioning spring is inserted into the relay shaft. After pressing and making contact with the center hole of the shaft end of the motor, the relay shaft and the positioning tool are screwed into the center hole through the coupling tool, and the relay shaft is connected to the shaft end, and then the relay shaft is connected to the hollow shaft of the rotary encoder. Is inserted, and the fastener is further engaged with the relay shaft to fix the hollow shaft to the relay shaft.

In the rotary encoder mounting device according to the present invention, as described above, the cylindrical positioning tool whose tip is processed into a conical shape is screwed into the inner surface of the end of the relay shaft so as to contact the center hole. Is. The center hole is formed in a conical shape when machining the motor shaft, and its center coincides with the shaft center of the motor.
For this reason, the center of the relay shaft, i.e., the axis of the rotary encoder, and the center of the center hole, i.e., the axis of the electric motor, are matched with high accuracy by a simple operation of bringing the positioning tool into contact with the center hole. There is an effect that it is possible.
In addition, when a rotary encoder is attached to an existing motor, a tapping operation for threading the center hole is required, but the connecting tool that is screwed into this screw simply connects the relay shaft to the shaft end. Not too much. For this reason, the tap erecting work is accurate to the extent necessary for the coupling tool to be screwed together, and has the effect that it can be easily carried out at the installation site of the electric motor.

Further, in another rotary encoder mounting apparatus according to the present invention, a positioning tool is inserted into the relay shaft and pressed by a pressing spring, and the positioning tool is mounted in contact with the center hole of the shaft end of the motor. Is.
Even in this case, as in the above-described invention, the axis of the rotary encoder and the axis of the electric motor can be matched with high accuracy.
In particular, since the positioning tool is advanced by being pushed by the pressing spring, it is not necessary to artificially set the exposure dimension, and the positioning tool is exposed to a predetermined dimension according to the depth of the center hole. For this reason, there is also an effect that the mounting operation of the rotary encoder becomes easier.

Embodiments of the present invention will be described below with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the part which is the same or it corresponds, and duplication of description was omitted.
Embodiment 1 FIG.
1 to 5 show a first embodiment of the present invention.
FIG. 1 is a longitudinal sectional view of a shaft end portion of an electric motor to which a rotary encoder having a hollow shaft is attached. FIG. 2 to FIG. 5 are explanatory views showing the process of attaching the rotary encoder by a longitudinal sectional view of the shaft end portion of the electric motor.
In FIG. 1, the shaft end 2 of the electric motor is exposed by a predetermined dimension from the electric motor bracket 1, and the end surface is finished to a plane orthogonal to the axial center of the electric motor. Further, a conical center hole 3 formed in the machining process of the motor shaft is formed on the end face. The center hole 3 is formed in a conical shape with a center hole angle θ1. A screw hole 4 is formed in the center of the center hole 3. This screw hole 4 is a hole that has been drilled in advance or is newly drilled when the rotary encoder 16 is attached.

A flange 11 a is provided at one end of the cylindrical relay shaft 11. A female screw 11c is threaded on the inner surface of the end portion on the flange 11a side. A male screw 11b is threaded on the outer surface of the end portion on the side opposite to the flange 11a. A cylindrical positioning tool 12 whose tip is processed into a conical shape with a conical angle θ2 is screwed into the female screw 11c of the relay shaft 11. This positioning tool 12 has a conical tip portion exposed from one end of the relay shaft 11 by a predetermined dimension δ, and this exposed portion is fitted in a center hole 3 formed in the shaft end 2 of the electric motor.
Here, it is assumed that the cone angle θ2 of the positioning tool 12 is equal to the center hole angle θ1, and the predetermined dimension δ is the conical surface of the positioning tool 12 when the outer end surface of the flange 11a contacts the end surface of the shaft end 2. 12 a is a dimension set so as to contact the inclined surface 3 a of the center hole 3.

In a state in which the positioning tool 12 is fitted in the center hole 3, the connecting tool 13 including the bolt 13 is passed through the relay shaft 11 and the positioning tool 12 and screwed into the screw hole 4. Is pressed against the shaft end 2 of the electric motor. Further, a knock pin 15 is driven into the flange 11 a and the shaft end 2 to fix the relay shaft 11 to the shaft end 2.
After passing the hollow shaft 17 of the rotary encoder 16 through the relay shaft 11, a fastener 18 made of a lock nut is screwed into the male screw 11b. The hollow shaft 17 is sandwiched between the flange 11 a and the fastener 18 and attached to the relay shaft 11. Furthermore, the main body of the rotary encoder 16 is attached to the electric motor bracket 1 which is a fixed portion by an attachment screw 20 via an attachment leg 19 made of a leaf spring.

Next, a method of attaching the rotary encoder will be described with reference to FIGS. The center hole 3 is normally drilled in the manufacturing process of the electric motor shaft 2 as described above. Therefore, it is not included in the mounting process of the rotary encoder 16.
First, tapping is performed at the bottom of the center hole 3 to form the screw hole 4. The positioning tool 12 is screwed into the end portion of the relay shaft 11 so that the tip portion processed into a conical shape is exposed from the relay shaft 11 by a predetermined dimension δ. The positioning tool 12 screwed to the relay shaft 11 is fitted into the center hole 3. A bolt 13 as a coupling tool is inserted into the relay shaft 11 and the positioning tool 12 and screwed into a screw hole 4 formed in the center hole 3. The relay shaft 11 to which the positioning tool 12 is attached is connected to the shaft end 2 by tightening the bolt 13. Further, as shown in FIG. 5, a knock pin 15 is driven into the flange 11 a and the shaft end 2 to fix the relay shaft 11 to the shaft end 2.

Here, when the positioning tool 12 is exposed to be larger than the predetermined dimension δ, as shown in FIG. 3, when the conical surface 12 a of the positioning tool 12 abuts the inclined surface 3 a of the center hole 3, the flange 11 a A gap is formed between the end surfaces of the shaft end 2.
On the other hand, it is desirable that the center of the screw hole 4 coincides with the axis of the electric motor. However, since the screw hole 4 is newly drilled at the installation site of the electric motor in order to attach the rotary encoder 16, it is assumed that the accuracy thereof is low. Therefore, as shown in FIG. 3, it is assumed that the center of the screw hole 4 is eccentric by an angle α with respect to the axis of the electric motor. When the bolt 13 is screwed into the screw hole 4, the bolt 13 is inclined with respect to the shaft end 2 of the electric motor. For this reason, the relay shaft 11 is regulated by the washer 14 and attached eccentrically with the bolt 13 by an angle α. When the rotary encoder 16 is attached to the relay shaft 11 in this state, vibration is generated.

  Conversely, when the positioning tool 12 is smaller than the predetermined dimension δ, as shown in FIG. 4, the flange 11 a and the end surface of the shaft end 2 come into contact with each other, and the conical surface 12 a of the positioning tool 12 and the inclined surface 3 a of the center hole 3 There is a gap between them. For this reason, the positioning tool 12 does not fulfill the positioning function. Since there is a gap between the positioning tool 12 and the bolt 13, the relay shaft 11 moves by an amount corresponding to this gap. Therefore, regardless of the accuracy of the screw hole 4, the axis of the relay shaft 11 is eccentric from the axis of the motor by the distance β. Also in this case, vibration is generated when the rotary encoder 16 is attached to the relay shaft 11.

  In the first embodiment, by adjusting the screwing of the positioning tool 12, the tip of the positioning tool 12 is exposed by a predetermined dimension δ, so that the outer end surface of the flange 11 a comes into contact with the end surface of the shaft end 2. The conical surface 12 a of the positioning tool 12 contacts the inclined surface 3 a of the center hole 3. For this reason, regardless of the accuracy of the screw hole 4, the relay shaft 11 protrudes in parallel with the motor shaft by the contact between the outer end surface of the flange 11 a and the end surface of the shaft end 2. Moreover, the axial center of the relay shaft 11 can be made to correspond with the motor shaft center by contact | abutting with the conical surface 12a and the slope 3a.

  In order to attach the rotary encoder 16 to the relay shaft 11, as shown in FIG. 5, after passing the relay shaft 11 through the hollow shaft 17, the lock nut 18 is screwed to the male screw 11b of the relay shaft 11, so that the hollow shaft 17 is sandwiched between the flange 11 a and the fastener 18 and attached to the relay shaft 11. Furthermore, by attaching the mounting leg 19 fixed to the main body of the rotary encoder 16 to the electric motor bracket 1 with the mounting screw 20, the mounting operation of the rotary encoder 16 to the electric motor is completed.

In the rotary encoder mounting device described in the first embodiment, the cylindrical positioning tool 12 whose tip is processed into a conical shape is screwed onto the inner surface of the end of the relay shaft 11 and exposed by a predetermined dimension δ. In this state, the center hole 3 is brought into contact. Accordingly, the outer end surface of the flange 11 a contacts the end surface of the shaft end 2, and at the same time, the conical surface 12 a of the positioning tool 12 contacts the inclined surface 3 a of the center hole 3.
For this reason, by a simple operation of bringing the positioning tool 12 into contact with the center hole 3, the axis of the relay shaft 11, that is, the axis of the rotary encoder 16, and the center of the center hole 3, that is, the axis of the electric motor 1. Can be matched with high accuracy.
Further, when the rotary encoder 16 is attached to an existing electric motor, a tapping operation for drilling the screw hole 4 in the center hole 3 is required. The relay shaft 11 is merely connected to the shaft end 2 and is not for aligning the shaft center of the rotary encoder 16 and the shaft center of the electric motor 1. For this reason, the tapping work may be of an accuracy necessary for the bolts 13 to be screwed together and can be easily performed at the installation site of the electric motor.

The flange 11a is provided at one end of the relay shaft 11. However, the present invention is not limited to this, and the end surface may be a plane that is orthogonal to the central axis of the relay shaft 11.
Further, although the knock pin 15 is driven into the flange 11a and the shaft end 2, the knock pin 15 can be omitted when the bolt 13 is attached sufficiently firmly.
Further, instead of the lock nut 18 as a fastener, a key may be driven between the relay shaft 11 and the hollow shaft 17a.

Embodiment 2. FIG.
6 to 8 show a second embodiment of the present invention. FIG. 6 is a longitudinal sectional view of the shaft end 2 of the electric motor to which the rotary encoder 16 is connected. 7 and 8 are explanatory views showing the process of attaching the rotary encoder.
In the second embodiment, as shown in FIG. 6, the positioning tool 32 is pressed by a pressing spring 33 so as to be exposed from the relay shaft 31.
That is, a flange 31 a is similarly provided at one end of the cylindrical relay shaft 31. A male screw 31b is threaded on the outer surface of the end portion on the side opposite to the flange 11a. A positioning tool 32 whose tip is processed into a conical shape is inserted into the relay shaft 31. The outer diameter of the positioning tool 32 is slightly smaller than the inner diameter of the relay shaft 31 and is in a fitting relationship with the relay shaft 31. A push spring 33 is also inserted into the relay shaft 31.

  As shown in FIG. 7, in a state where the flange 31 a of the relay shaft 31 is in contact with the end surface of the shaft end 2, the coupling tool 13 including the bolt 13 is passed through the relay shaft 31 and the positioning tool 32 to form the screw hole 4. Screw together. The relay shaft 31 is pressed against the end surface of the shaft end 2 through the washer 14 as the screwing proceeds. The push spring 33 is compressed via the washer 14 and presses the positioning tool 32. By this pressing, the positioning tool 32 exposes the tip portion by a predetermined dimension δ and fits the center hole 3 formed in the shaft end 2 of the electric motor to position the relay shaft 31. In other words, the relay shaft 31 is connected to the shaft end of the motor in a state where the shaft center is aligned with the shaft center of the motor by press-contacting the outer surface of the flange 31a and the end surface of the shaft end 2 and fitting of the positioning tool 32 and the center hole 3. 2 connected.

Hereinafter, as shown in FIG. 8, the knock pin 15 is driven into the flange 31 a and the electric motor bracket 1 in the same manner as in the first embodiment to ensure the attachment. After passing the attached relay shaft 31 through the hollow shaft 17 of the rotary encoder 16, the lock nut 18 is screwed into the male screw 31 b, and the main body of the rotary encoder 16 is attached to the electric motor bracket 1 by the attachment leg 19.
As in the first embodiment, the flange 31a is provided at one end of the relay shaft 31. However, the present invention is not limited to this, and the end surface is finished in a plane perpendicular to the central axis of the relay shaft 31. I just need it.
Further, although the knock pin 15 is driven into the flange 31a and the shaft end 2, the knock pin 15 can be omitted when the bolt 13 is attached sufficiently firmly.
Further, similarly to the first embodiment, a key may be driven between the relay shaft 11 and the hollow shaft 17a instead of the lock nut 18.

According to the second embodiment, the positioning tool 32 is inserted into the relay shaft 31 and pressed by the pressing spring 33, and the positioning tool 32 is fitted and attached to the center hole 3 of the shaft end 2 of the electric motor. Therefore, similarly to the first embodiment, the axis of the rotary encoder 16 and the axis of the electric motor can be matched with high accuracy.
In particular, since the positioning tool 32 is advanced by being pushed by the pressing spring 33, it is not necessary to artificially set the exposure dimension, and the positioning tool 32 is exposed to a predetermined dimension δ according to the depth of the center hole 3. To do. For this reason, there is also an effect that the mounting operation of the rotary encoder 16 becomes easier.

1 is a longitudinal section of a rotary encoder mounting device according to Embodiment 1 of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional view showing an initial process of a rotary encoder mounting operation in Embodiment 1 of the present invention. Explanatory drawing which shows the principal point of the attachment work of the rotary encoder in Embodiment 1 of this invention. Explanatory drawing which shows the principal point of the attachment work of the rotary encoder in Embodiment 1 of this invention. The longitudinal cross-sectional view which shows the latter process of the attachment work of the rotary encoder in Embodiment 1 of this invention. The longitudinal cross-section of the rotary encoder attachment apparatus in Embodiment 2 of this invention. The longitudinal cross-sectional view which shows the initial process of the attachment work of the rotary encoder in Embodiment 2 of this invention. The longitudinal cross-sectional view which shows the latter process of the attachment work of the rotary encoder in Embodiment 2 of this invention. The front view of the conventional rotary encoder attachment apparatus. Sectional drawing of the attachment apparatus of the rotary encoder which looked at the XX line cross section of FIG. The front view of the other attachment apparatus of the conventional rotary encoder. Sectional drawing of the attachment apparatus of the rotary encoder which looked at the XII-XII line cross section of FIG.

Explanation of symbols

  1 motor bracket, 2 shaft end, 3 center hole, 3a inclined surface, 4 screw hole, 11 relay shaft, 11a flange, 11b male screw, 11c female screw, 12 positioning tool, 12a conical surface, 13 bolt, 14 washer, 15 dowel pin, 16 rotary encoder, 17 hollow shaft, 18 lock nut, 19 mounting leg, 20 mounting screw, 31 relay shaft, 31a flange, 31b male screw, 32 positioning tool, 32a conical surface, 33 push spring.

Claims (4)

  An attachment device for attaching a rotary encoder for converting a rotation angle of a rotatable hollow shaft into an electric signal to a shaft end of an electric motor, a cylindrical relay shaft inserted into the hollow shaft and rotating together with the hollow shaft, and the relay A tip portion that is screwed into a screw formed on the inner surface of the shaft end and processed into a conical shape is exposed from the relay shaft by a predetermined dimension, and is fitted into a center hole formed in the shaft end of the motor. A cylindrical positioning tool for positioning the relay shaft, a coupling tool that penetrates the relay shaft and the positioning tool and is screwed into the center hole, and connects the relay shaft to the shaft end of the motor; A rotary encoder mounting device comprising: a fastener for fixing the hollow shaft to the relay shaft.   An attachment device for attaching a rotary encoder for converting a rotation angle of a rotatable hollow shaft into an electric signal to a shaft end of an electric motor, a cylindrical relay shaft inserted into the hollow shaft and rotating together with the hollow shaft, and the relay A cylindrical positioning tool that exposes a tip portion that is inserted into the shaft and processed into a conical shape, fits into a center hole formed in the shaft end of the electric motor, and positions the relay shaft; and A push spring that is inserted into the relay shaft and presses the positioning tool to fit into the center hole, and passes through the relay shaft and the positioning tool and is screwed into the center hole to compress the push spring. And a rotary encoder mounting device comprising: a connecting tool for connecting the relay shaft to the shaft end of the electric motor; and a fastener for fixing the hollow shaft to the relay shaft.   A tapping step for threading a center hole formed at the shaft end of the electric motor, and a positioning for exposing a predetermined dimension from the relay shaft by screwing a positioning tool into the end portion of the relay shaft to form a conical shape. Fitting step, fitting the positioning tool into the center hole, inserting the coupling tool into the relay shaft and screwing it into the center hole, and connecting the relay shaft with the positioning tool attached to the shaft end. The rotary encoder mounting method using the mounting device according to claim 1, further comprising: a relay shaft connecting step for connecting to the shaft, and a hollow shaft mounting step for mounting the hollow shaft of the rotary encoder on the relay shaft connected to the shaft end.   A tapping step for threading a center hole formed at the shaft end of the motor, a positioning tool insertion step for inserting a positioning tool whose tip is processed into a conical shape into the relay shaft, and a push spring being inserted into the relay shaft A push spring insertion step, a connecting tool is inserted into the relay shaft and screwed into the center hole, and as the screwing progresses, the push spring is pressed to expose the positioning tool, and the center hole is inserted into the center hole. 3. A relay shaft connecting step of fitting and connecting the relay shaft to the shaft end, and a hollow shaft mounting step of attaching a hollow shaft of the rotary encoder to the relay shaft connected to the shaft end. A mounting method of the rotary encoder by the mounting device described in 1.

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