JP2002044910A - Motor rotation detecting mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor rotation detecting mechanism in which a bearing sensor can be removed easily from an end cover. SOLUTION: A bearing sensor 20, where a sensor 21 and a bearing part 22 are unitized, is fitted into a recess 37 formed in an end cover 32 of a motor, and an outer ring 26 of the bearing part 22 is protruded toward further inside of the end cover 32. In a plate member 36, a recess 38 is formed to be mated with a corner 26a of the protruded outer ring 26. According to this constitution, after the plate member 36 is removed, the bearing sensor 20 can be taken out by gripping the extruded outer ring 26, thereby facilitating the operation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation detecting mechanism for a motor mounted on a battery forklift or the like.

[0002]

2. Description of the Related Art A battery forklift is equipped with a traveling motor, a hydraulic motor, and a steering motor. These motors are provided with a rotation detection mechanism for detecting the number of rotations and performing feedback control. FIG. 5 is a partial sectional view showing an example of a conventional motor provided with such a rotation detecting mechanism. In FIG. 5, the motor 1 includes a pair of front and rear end covers 2, 3, a stator core 4 constituting a stator, and a rotor 5 disposed inside the stator core 4.

The end cover 2 has a partition wall 6 inside, and a motor shaft 9 provided integrally with the rotor 5 via a bearing 8 provided with a sphere 7 at the center of the partition wall 6.
Is supported at one end. The other end of the motor shaft 9 is supported by the end cover 3 via a bearing 13 having a sphere 12. Reference numeral 10 denotes an encoder connected to the motor shaft 9. The encoder 10 is for detecting the number of revolutions of the motor 1, and is constituted by an optical or magnetic rotary encoder. Reference numeral 11 denotes a winding that constitutes a stator together with the stator core 4, and 14 denotes a protective cover that covers an opening of the end cover 2.

In the above-described motor 1, an encoder 10 is required as rotation detecting means. Further, since the encoder 10 is attached to the end of the motor shaft 9, the motor 10 and the rotating shaft of the encoder 10 are connected to each other. Dimensional accuracy is required in order to match, and the cost increases. Further, it is necessary to take measures against heat influence from the motor shaft 9 to the encoder 10, and also requires components such as the protective cover 14. Moreover, since an axial dead space D is generated,
This is an obstacle for battery forklifts with limited installation space.

In addition, instead of the above encoder,
A rotation plate having a tooth portion on the outer periphery is attached to an end of the motor shaft, and a rotation sensor such as a proximity switch is provided so as to face the tooth portion. Is required, and a dead space in the axial direction occurs as in FIG.

As a solution to such a problem, there is a method using a bearing sensor instead of a conventional encoder or the like. The bearing sensor integrates a sensor unit for detecting the number of rotations of the motor and a bearing unit for supporting the motor shaft, and FIG. 9 shows a schematic structure thereof. FIG. 9A is a front view, and FIG. 9B is a right side sectional view.
The bearing sensor 20 includes a sensor unit 21 and a bearing unit 22. These have an annular shape, and a through hole 23 through which the motor shaft is inserted is formed in the center of the ring. Reference numeral 24 denotes a lead wire drawn out of the sensor unit 21 to the outside.

The bearing portion 22 includes an inner ring 25, an outer ring 26, and a sphere 27 sandwiched between the two rings. The inner ring 25 rotates integrally with the motor shaft. 26 is fixed, and the sensor unit 21 is attached. As shown in FIG.
An annular magnetic pole 28 along the ring is fixed to the inner ring 25 by a support member 29, and a magnetic detecting element 30 is provided in the sensor section 21 so as to face the magnetic pole 28. Reference numeral 31 denotes a housing of the sensor unit 21 to which the magnetic detection element 30 is attached.

FIG. 11 is a diagram for explaining the operation principle of the bearing sensor 20. The magnetic pole 28 is alternately magnetized to the N pole and the S pole as shown in the figure, and the magnetic detection element 30 detects the N pole and the S pole by rotating the magnetic pole 28 in the direction of the arrow with the rotation of the inner ring 25. This is converted into a pulse signal, and the number of rotations of the motor is detected.

FIG. 6 shows an example in which the above-described bearing sensor 20 is used as a motor rotation detecting means.
The state where the bearing sensor 20 is attached to the end cover 32 of the motor is shown. (A) is a front view when the end cover is viewed from the inside, and (b) is a right side sectional view thereof. The bearing sensor 20 is fitted into the inside of the end cover 32, the annular plate member 33 is applied from above, and the plate member 33 is fixed to the end cover 32 by a bolt 34 as an attachment member.
It is sandwiched and fixed between the end cover 32 and the plate member 33.

FIG. 7 is an enlarged view of a fixed portion of the bearing sensor 20. An annular recess 35 is formed inside the end cover 32, and the outer ring 26 of the bearing portion 22 is fitted into the recess 35. Recess 3
The width of the outer ring 26 and the inner surface of the end cover 32 are flush with each other when the outer ring 26 is fitted in the recess 35. . Therefore, when the plate member 33 is fixed to the end cover 32, a part of the outer ring 26 (the left side surface in the figure) is pressed by the plate member 33, as indicated by a broken line B in the figure, whereby the bearing sensor 2
0 is fixed between the end cover 32 and the plate member 33 by closing the left and right movements.

As described above, if a bearing sensor is used as the rotation detecting means, an encoder and a rotating plate are not required, so that the number of parts can be reduced, the cost can be reduced, and the dead space can be eliminated. be able to.

[0012]

In the bearing sensor mounting structure described above, when the bearing sensor 20 is detached from the end cover 32 for maintenance or replacement, first, the motor shaft 9 (FIG. 7) is pulled out from the bearing portion 22. . Thereafter, the bolt 34 is loosened to remove the plate member 33 from the end cover 32. Finally, the bearing sensor 2
0 is taken out from the concave portion 35 of the end cover 32.

Here, the state when the plate member 33 is detached from the end cover 32 is as shown in FIG. 8, and as described above, the outer ring 26 and the inner surface of the end cover 32 are flush. I have. For this reason, the outer ring 26 cannot be grasped with a hand or a jig and the bearing sensor 20 cannot be taken out in the direction of the arrow. Although the sensor section 21 protrudes from the inner surface of the end cover 32, pulling out the bearing sensor 20 while gripping the sensor section 21 requires an excessive force to be applied to the sensor section 21 and causes the position accuracy of the magnetic detection element 30 to be reduced. It is not preferable because it has an adverse effect on the operation. Therefore, the bearing sensor 20 is taken out from the inner ring 25.
And pulling it out in the direction of the arrow.

However, since the inner ring 25 is also flush with the end cover 32, it is difficult to hold the inner ring 25 and pull it out.
7 from the outer ring 26 to the sensor unit 21, which may adversely affect the positional accuracy of the magnetic detection element 30. For this reason, the inner ring 25 must be carefully pulled out, and there is a problem that the operation requires time and labor.

In the structure shown in FIG. 7, the joint between the end cover 32 and the plate member 33 is located at the corner 26a of the outer ring 26, as can be seen from the portion indicated by the broken line B. 32 and plate member 3
3 are separate members from each other.
It is practically impossible to make the shape along the R of 6a. Therefore, the corner 26a is connected to the end cover 3
2 and the plate member 33 cannot completely press down,
There is a possibility that the fixing of the bearing sensor 20 becomes insufficient.

An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide a motor rotation detecting mechanism capable of easily removing a bearing sensor from an end cover. Another object of the present invention is to provide a motor rotation detection mechanism capable of firmly attaching a bearing sensor to an end cover.

[0017]

According to the present invention, a bearing portion is fitted into a first concave portion formed in an end cover of a motor, and is protruded inward from the end cover. A second recess is formed to fit with the corner. With this configuration, the bearing portion protrudes inward from the end cover with the plate member removed, so that the outer ring of the protruding bearing portion can be gripped and the bearing sensor can be easily removed from the end cover. , Work can be done quickly.

In the present invention, since the second concave portion into which the corner of the bearing portion is fitted is formed in a plate member made of a single member, the second concave portion is processed into a shape along the corner. Therefore, the corner of the bearing portion can be brought into surface contact with the second concave portion. Therefore, the bearing portion can be attached to the end cover in a state where the entire area of the corner is pressed by the second concave portion, and the bearing sensor is securely fixed.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described.
This will be described with reference to FIGS. FIGS. 1A and 1B are diagrams showing an end cover of a motor to which a rotation detecting mechanism according to the present invention is attached, wherein FIG. 1A is a front view when the end cover is viewed from the inside, and FIG. . As in FIG. 6, the bearing sensor 20 is fitted inside the end cover 32, and the annular plate member 36
Then, the plate member 36 is fixed to the end cover 32 by the bolt 34 as an attachment member, so that the plate member 36 is sandwiched and fixed between the end cover 32 and the plate member 36. Since the structure and operating principle of the bearing sensor 20 are the same as those described with reference to FIGS. 9 to 11, the details are omitted here.

FIG. 2 is an enlarged view showing a fixed portion of the bearing sensor 20. An annular concave portion 37 serving as a first concave portion is formed inside the end cover 32.
The outer ring 26 of the bearing portion 22 is fitted into the recess 37. The width of the recess 37 is set smaller than the width of the outer ring 26.
When the outer ring 26 is engaged with the end cover 32,
It protrudes more inward. On the other hand, the plate member 36 is formed with an annular concave portion 38 which is a second concave portion.

Therefore, when the plate member 36 is fixed to the end cover 32, the corner 26a of the outer ring 26 is pressed by the concave portion 38 of the plate member 36, as indicated by a broken line A in the drawing, whereby the bearing sensor 20 The left and right movements are sealed and the end cover 32
And the plate member 36.

In this case, the inner surface of the concave portion 38 is
The sixth corner 26a is formed into a shape along the radius R, and the corner 26a is in surface contact with the concave portion 38. Therefore, since the bearing portion 22 is attached to the end cover 32 in a state where the entire area of the corner 26a is pressed by the concave portion 38, the bearing sensor 20 can be firmly fixed.

When the bearing sensor 20 is to be removed from the end cover 32 for maintenance or replacement, the motor shaft 9 is firstly pulled out of the bearing portion 22, the bolts 34 are loosened, and the plate member 36 is removed from the end cover 32, as in the prior art. After the bearing sensor 20 is removed from the end cover 32, the entire bearing sensor 20 is removed from the recess 37 of the end cover 32.

Here, the state when the plate member 36 is removed from the end cover 32 is as shown in FIG. 3, and the outer ring 26 protrudes from the end cover 32 as described above. Therefore, in order to take out the bearing sensor 20, it is sufficient to hold the outer ring 26 with a hand or a jig and pull it out in the direction of the arrow, and it is not necessary to hold and pull out the inner ring 25. Therefore, the bearing sensor 20 can be easily taken out without giving an excessive force to the sensor section 21, and the operation can be performed smoothly and efficiently.

FIG. 4 is a partial sectional view of a forklift motor provided with the above-described rotation detecting mechanism. 1 is a motor, 3 is one end cover, 4 is a stator core,
5 is a rotor, 9 is a motor shaft, 11 is a winding, 12 is a sphere,
Reference numeral 13 denotes bearings, which are the same as those shown in FIG. Reference numeral 32 denotes the end cover shown in FIG.
2 are mounted. In the motor 1 shown in FIG. 4, the use of the bearing sensor 20 eliminates the dead space D shown in FIG. For this reason, it is convenient to mount the battery on a battery forklift, which has a lot of space restrictions.

The present invention can be applied not only to forklifts but also to motors of, for example, automatic guided vehicles and high-altitude working vehicles. In general, it can be widely applied.

[0027]

According to the present invention, the operation of taking out the bearing sensor can be easily and quickly performed by projecting the bearing portion from the end cover. Also,
The bearing sensor can be firmly attached by bringing the recess of the plate member into surface contact with the corner of the bearing portion.

[Brief description of the drawings]

FIG. 1 is a view showing an end cover of a motor to which a rotation detection mechanism according to the present invention is attached.

FIG. 2 is an enlarged view showing a fixed portion of a bearing sensor.

FIG. 3 is a view showing a state where a plate member is removed.

FIG. 4 is a partial cross-sectional view of a forklift motor.

FIG. 5 is a partial sectional view of a motor provided with a conventional rotation detection mechanism.

FIG. 6 is a view showing an end cover of a motor to which a bearing sensor is attached.

FIG. 7 is an enlarged view of a fixed portion of the bearing sensor.

FIG. 8 is a view showing a state where a plate member is removed.

FIG. 9 is a diagram showing a bearing sensor.

FIG. 10 is a sectional view of a main part of a bearing sensor.

FIG. 11 is a diagram illustrating the operation principle of the bearing sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Motor 9 Motor shaft 20 Bearing sensor 21 Sensor part 22 Bearing part 25 Inner ring 26 Outer ring 26a Corner 27 Sphere 32 End cover 36 Plate member 37 Depression (first depression) 38 Depression (second depression)

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3J017 AA01 AA04 CA01 CA07 DB01 3J101 AA02 AA42 AA62 BA77 FA60 GA24 5H611 AA01 BB01 PP05 QQ01 RR02 UA05 UB00

Claims (3)

[Claims] The present invention further comprises a bearing sensor in which a sensor unit for detecting the rotation speed of the motor and a bearing unit for supporting the motor shaft are integrated, and the bearing sensor is mounted on an end cover of the motor by a plate member. In the detection mechanism, the bearing portion is fitted in a first concave portion formed in an end cover of the motor, and protrudes inward from the end cover, and is fitted to a corner of the protruding bearing portion in the plate member. A rotation detecting mechanism for a motor, wherein a second concave portion is formed. 2. The motor rotation detecting mechanism according to claim 1, wherein the second recess is formed in a shape along a corner of the bearing portion, and the corner is in surface contact with the second recess. 3. The bearing unit includes an inner ring that rotates integrally with the motor shaft, an outer ring to which the sensor unit is attached,
3. The motor rotation detecting mechanism according to claim 1, comprising a sphere sandwiched between the two rings, wherein the outer ring is fitted in the first concave portion and the second concave portion.