JP2003088035A - Motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of abnormal noise from ball bearings in a motor which supports a rotor shaft with the ball bearings. SOLUTION: This motor comprises a holder part extending in an inner side shaft direction from a low wall part 7 of a casing 20 and having a through hole 30, and ball bearings 2, 3 provided at both end parts of the holder part 6 and the through hole 30 of the holder part 6. The motor supports the rotor shaft 1 with the ball bearings 2, 3. Compression springs 5 are provided between respective inner rings of the ball bearings 2, 3 through spring bearings 4, 4 respectively. An inner ring 3A of the ball bearing 3 is installed at the rotor shaft 1 so as to slide in the axial direction and an inner ring 2A of the other ball bearing 2 is fixed at the rotor shaft 1. Repulsion of the compression spring 5 is transmitted to the inner rings 2A, 3A of the ball bearings through the spring bearings 4, 4, the ball bearings are pre-pressurized, and looseness in the ball bearing is eliminated, thus the generation of abnormal noise can be prevented.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a motor.

[0002]

2. Description of the Related Art Conventionally, there is a coreless motor as shown in FIG. The cylindrical case portion 51 and the metal holder portion 52 are integrally molded to form a housing 53. The rotor 57 is supported by bearing metals 54 and 55 attached to both ends of the metal holder portion 52,
A magnet 56 is fitted around the outer circumference of 2.

The rotor 57 comprises a rotor shaft 63, a cylindrical coreless winding 58, and an end block 59 connecting the rotor shaft 63 and the rotor 57. The end block 59 has a commutator 60. Bearing metal 54, 5
5, the rotor shaft 63 is rotatably supported, and the coreless winding 58 is arranged in the gap between the magnet 56 and the inner wall of the cylindrical case 51. At the opening end of the housing 53, a cap 62 including a brush 61 that is in sliding contact with the commutator 60 is attached. A similar structure of a coreless motor is disclosed in, for example, Japanese Patent Laid-Open No. 2001-157400.

[0004]

However, in the above-mentioned conventional structure, the bearing metal 54, 55 is used for the bearing of the rotor shaft 63, and when the rotor shaft 63 rotates, the bearing metal 54, 55 has a large friction and the rotational efficiency is high. Is not good. Therefore, it is conceivable to use a ball bearing for the bearing of the rotor shaft 63 in order to improve the rotation efficiency. However, when a ball bearing is used as the bearing of the rotor shaft, if the ball bearing has backlash, an abnormal noise is generated due to the vibration. Therefore, it is necessary to preload the ball bearing to prevent vibration. Therefore, a method of preloading the ball bearing using a compression spring and a spring bearing can be considered, but the structure becomes complicated as the number of parts increases, and the number of steps in the assembly process tends to increase.

Therefore, the present invention has been made in view of the above problems.
An object of the present invention is to provide a motor capable of preloading a ball bearing while improving assembly workability.

[0006]

The invention according to claim 1 is
A holder portion that extends from the bottom wall portion of the casing in the inward axial direction and has a through hole, and ball bearings provided at both ends of the through hole of the holder portion, and support the rotor shaft on the ball bearing, A compression spring is provided between each inner ring of both ball bearings via a spring bearing, and an inner ring of at least one ball bearing is slidable in the axial direction of the rotor shaft, and the spring bearing is a shaft hole through which the rotor shaft passes. And a first inclined portion is provided in the opening of the shaft hole at the tip end that abuts the inner ring, and the difference between the outer diameter of the spring bearing and the diameter of the through hole of the holder portion is 2A, and the tip surface of the spring bearing is The difference between the diameter of the opening edge of the first inclined portion and the diameter of the rotor shaft is set to 2C, A <C is set, and the compression springs apply preload to the ball bearings respectively. It was the thing. Two spring bearings attached to both ends of the compression spring push the inner rings of the ball bearings, which are in contact with each other, by the repulsive force of the compression springs. By sandwiching and pressing, the balls of the ball bearing and the outer ring and the inner ring have no clearance, and each ball bearing is preloaded.

According to a second aspect of the invention, the difference between the diameter of the shaft hole of the spring bearing and the diameter of the rotor shaft is 2B, and B <
It is assumed that it is set to A.

According to a third aspect of the present invention, a large diameter portion for accommodating the end portion of the compression spring is provided on the rear end side of the spring receiver coaxially with the shaft hole.

According to a fourth aspect of the present invention, a second inclined portion is formed on the outer peripheral portion of the tip of the spring bearing, and the inner diameter of the outer ring of the ball bearing on the spring bearing side is 2D, and the tip surface of the spring bearing is formed. It is assumed that the diameter of the outer peripheral edge is set to be smaller than 2D.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Next, embodiments of the present invention will be described with reference to examples. FIG. 1 is a sectional view showing the configuration of the embodiment. In the coreless motor, the cylindrical case portion 8 and the end wall portion 7 having the holder portion 6 extending into the case portion form a casing 20, and the rotor 19 is accommodated therein.

The holder portion 6 is provided with a through hole 30 in the axial direction, and an enlarged portion 21 having an inner diameter larger than the general inner diameter of the through hole 30 is formed in the opening portion of the through hole 30 on the end wall portion 7 side. The outer ring 2B of the ball bearing 2 is press-fitted into the enlarged portion 21 from the outside. Further, an enlarged portion 29 having an inner diameter larger than the general inner diameter of the through hole 30 is formed in the opening portion on the inner end side of the through hole 30, and the outer ring 3B of the ball bearing 3 is press-fitted into the enlarged portion 29. A magnet 9 is fitted around the holder portion 6. Magnet 9
One end of the ball bearing 3 projects slightly from the end surface of the ball bearing 3.

The rotor 19 has a cylindrical coreless winding 10 arranged in the gap between the magnet 9 and the cylindrical case portion 8 with the rotor shaft 1 rotatably supported by the ball bearings 2 and 3 as an axis, and the coreless winding. The end block 11 connects the wire 10 and the rotor shaft 1, and the end block 11 is provided with a commutator 12. The inner ring 2A of the ball bearing 2 is press-fitted into the rotor shaft 1. The inner ring 3A of the ball bearing 3 is attached to the rotor shaft 1 so as to freely slide in the axial direction.

Between the two ball bearings 2 and 3,
A compression spring 5 is provided so as to surround the rotor shaft 1, and spring bearings 4 and 4 are provided on the end surface thereof. The repulsive force of the compression spring 5 urges the inner rings 2A and 3A of the ball bearings 2 and 3 through the spring bearings 4 and 4 to preload the ball bearings 2 and 3.

A metal bush 13 is cast in the center of the end block 11, and one end of the rotor shaft 1 is press-fitted into the bush 13 to be joined to the end block 11. The bush cast portion of the end block 11 has entered the inside of the magnet 9. A gap is set between the ball bearing 3 and the bush 13 so that the ball bearing 3 and the bush 13 do not come into contact with each other even when the rotor shaft 1 is displaced by preloading the ball bearings 2 and 3.

Outside the casing 20, a flange 14 is provided on the rotor shaft 1 near the ball bearing 2.
Is fixed, and a collar 22 is provided between the collar 14 and the ball bearing 2. When the collar 22 is pushed by the collar 14 and comes into contact with the end surface of the ball bearing 2, the movement of the rotor 19 in one direction is restricted.

A gap is formed between the coreless winding 10 and the outer peripheral surface of the magnet 9 and between the coreless winding 10 and the inner wall of the cylindrical case portion 8 so that they do not contact each other. A cap 15 having a brush 16 that is in sliding contact with the commutator 12 is attached to the open end of the cylindrical case 8. A commutator 1 is provided at the center of the cap 15.
The hole 17 having a diameter larger than the diameter of the portion that contacts the second brush 16
Is provided, and a cover member 18 that closes this hole is attached.

FIG. 2 shows an enlarged view of the spring receiver 4 portion of FIG. The spring bearing 4 has a shaft hole 31 through which the rotor shaft 1 passes, and a tip end that abuts the ball bearing 3 has an inclined portion 23 at the opening of the shaft hole 31. A large diameter portion 25 for accommodating the end portion of the compression spring 5 is provided at the rear end opposite to the front end coaxially with the shaft hole 31 at about 40% of the length of the spring receiver. The tip end of the compression spring 5 is brought into contact with the bottom wall of the large diameter portion 25 to urge the spring receiver 4.

Outer diameter of spring receiver 4 and through hole 3 of holder 6
0 is 2A, the diameter of the shaft hole 31 of the spring bearing 4 is 2B, and the diameter of the rotor shaft 1 is 2B.
It is assumed that the difference between the diameters of the two is 2C and the relations of B <A and A <C are satisfied. Further, the outer peripheral edge of the tip of the spring bearing 4 is chamfered to form an inclined portion 24, and the inner diameter of the outer ring of the ball bearing 3 on the spring bearing side is set to 2D, and the diameter of the outer peripheral edge of the tip surface of the spring bearing 4 is set. Is set to have a diameter smaller than 2D.

As described above, the compression spring 5 and the spring bearings 4 and 4 are provided around the rotor shaft 1, and the spring bearings 4 and 4 push the inner rings of the ball bearings 2 and 3 by the repulsive force of the compression spring 5. As a result, in the ball bearing 3, the ball 26 is expanded and preloaded between the contact points 27 and 28 of the inner rings 3A and 3B of the ball bearings 2 and 3, respectively. The same applies to the ball bearing 2.

When the ball bearings 2 and 3 are preloaded,
The inner ring 3A of the ball bearing 3 mounted on the rotor shaft 1 so that the inner ring slides freely in the axial direction has an outer ring 3 fixed to the holder portion 6 by the repulsive force of the compression spring 5.
The inner ring 2A of the ball bearing 2 in which the inner ring is fixed to the rotor shaft 1 is compressed by pressing the compression spring
The ball of the ball bearing is sandwiched between the outer ring 2B fixed to the holder part 6 by the repulsive force of the rotor, and the rotor shaft 1 fixed to the inner ring 2A is pressed together, so that there is no gap between the ball of the ball bearing and the outer ring, Each ball bearing is preloaded.

By providing an inclined portion 24 at the outer peripheral edge of the tip of the spring bearing 4 and making the outer peripheral edge diameter of the tip surface of the spring bearing 4 smaller than 2D, the spring bearing 4 is preloaded by preloading the ball bearing. When moving, even if the outer ring of the ball bearing protrudes into the through hole of the holder portion 6, the spring bearing 4 does not get caught by the outer rings 2B and 3B, and the spring bearing 2A and 3B are not caught.
A can be activated. Further, when the spring bearing 4 rotates together with the rotor 19 due to the relation of B <A, the spring bearing 4
The outer circumference does not come into contact with the through hole 30 of the holder portion 6, and smooth rotation is secured.

The coreless motor having the above structure is assembled in the following procedure. First, a subassembly in which the ball bearing 3 and the magnet 9 are attached to the casing 20 is prepared. The mounting order of the ball bear rig 3 and the magnet 9 is appropriately determined.

Next, as shown in FIG.
Is composed of a base 42 and a shaft 41, and the shaft 41 has a diameter slightly smaller than the inner diameters of the bearings 2 and 3. The base 42 is provided with a hole for inserting the shaft 41, and an opening 43 for accommodating the collar 22 and the collar 14 is provided at the opening end of the inserting hole of the shaft 41.
The depth of 3 is set to be slightly deeper than the thickness of the collar 22 and the collar 14.

As shown in FIG. 3 (b), the spring 41 is inserted into the shaft 41 inserted into the base 42 in this order from the top.
Compression spring 5, spring bearing 4, bearing 2, collar 22,
Fit so that it becomes the brim 14. Next, as shown in FIG. 3C, the assembled casing 20 is inserted into the shaft 41 from the end wall portion 7 side, and the outer ring 2B of the ball bearing 2 is press-fitted into the enlarged portion 21 of the end wall portion 7.

Next, as shown in FIG. 4D, the shaft 41 is pulled out. Next, as shown in FIG. 4 (e), the rotor shaft 1 of the rotor 19 pre-assembled is inserted into the ball bearings 2 and 3, and the collar 2
2 is inserted into the collar 14 by press fitting and is placed in the casing 20. Inner ring 2A of rotor shaft 1 and ball bearing 2
Is pressed in.

By making the shape of the spring bearing 4 satisfy the relation of A <C, even if the spring bearing 4 is tilted or biased in the holder portion 6, when viewed from the axial direction, the spring bearing 4 is
The tip surface of is not visible inside the inner diameter of the inner ring of the ball bearing. Therefore, when inserting the rotor shaft 1 into the ball bearings 2 and 3 and the spring bearing 4,
The spring support 4 without hooking it on the tip surface of the spring support 4
Can be inserted into the shaft hole 31 of the.

Thereafter, the cap 15 is fitted into the opening of the cylindrical case 8 and the peripheral portion is fixed by caulking the end of the cylindrical case 8. At this time, a jig (not shown) is inserted through the hole 17 of the cap 15, and the elastic brush 16 is spread and placed on the commutator 12. Finally, the cover member 18 is attached to the hole 17 of the cap 15 to complete the process.

The present embodiment is constructed as described above, and in the motor using the ball bearings 2 and 3 as the bearings, the compression spring 5 and the spring bearing 4 are mounted between the ball bearings 2 and 3, so that the compression spring 5 The spring bearing 4 pushed by urges the inner rings 2A and 3A of each ball bearing,
Preload the ball bearings 2 and 3.

By satisfying the relation of A <C with respect to the spring bearing 4, even if the spring bearing 4 is tilted or biased in the holder portion 6 after the jig shaft is pulled out during assembly, When viewed from the direction, the tip end surface of the spring bearing 4 does not look into the inner diameters of the inner rings of the ball bearings 2 and 3. Therefore, the rotor shaft 1 can be inserted into the shaft hole 31 of the spring bearing 4 without being caught by the tip end surface of the spring bearing 4.

By setting B <A for the spring bearing 4, when the spring bearing 4 rotates together with the rotor 19,
The outer circumference of the spring receiver 4 does not come into contact with the through hole 30 of the holder portion 6, and smooth rotation is ensured.

In the above embodiment, when assembling the coreless motor using the jig, the flange 41, the collar 22, the ball bearing 2, the spring bearing 4, the compression spring 5, and the spring bearing 4 are attached to the shaft 41 inserted in the base 42. Although the sub-assembled casing 20 is to be inserted after mounting the above, the present invention is not limited to this. For example, after the collar 14 and the collar 14 are fitted into the shaft 41 inserted into the base 42, the ball bearing is inserted. 2 may be inserted into the casing 20 to which the magnet 9 is attached, and then the spring bearing 4, the compression spring 5, and the spring bearing 4 may be attached to press the outer ring 3B of the ball bearing 3 into the holder portion 6 of the casing 20.

The inner ring 2A of the ball bearing 2 is fixed to the rotor shaft 1 and the inner ring 3A of the other ball bearing 3 is slidable with respect to the rotor shaft 1. 1
The inner ring 3A of the other ball bearing 3 may be fixed to the rotor shaft 1. Further, both the inner rings 2A and 3A of the ball bearings 2 and 3 may slide with respect to the rotor shaft 1. It may be possible.

Further, although the large diameter portion 22 is provided in the through hole of the spring bearing 4 to bring the compression spring into contact with the inner bottom wall, a small diameter portion is provided on the outer circumference of the spring bearing on the side not contacting the ball bearing. The compression spring may be attached so as to cover the small diameter portion.

[0034]

According to the first aspect of the present invention, the compression spring applies a preload to the ball bearings by urging the inner ring of each ball bearing through the spring bearing, so that the ball bearing play at the time of motor operation. It is possible to prevent the vibration due to, and to prevent the generation of abnormal noise.

Further, by setting the shape of the spring bearing to satisfy the relationship of A <C, the tip of the spring bearing can be seen from the axial direction even if the spring bearing is tilted or biased in the holder during assembly. The surface does not look into the inner diameter of the inner ring of the ball bearing. Therefore, the rotor shaft can be inserted into the shaft hole of the spring bearing without being caught by the tip end surface of the spring bearing, and the assembly becomes easy.

According to the second aspect of the present invention, by making the shape of the spring bearing satisfy the relation of B <A, when the spring bearing rotates together with the rotor, the outer circumference of the spring bearing becomes the through hole of the holder portion. Smooth rotation is ensured without contact.

According to the third aspect of the present invention, the tip end of the compression spring is brought into contact with the inner bottom wall of the large diameter portion of the spring receiver, and the compression spring is held by the spring receiver, so that the compression spring is secured during the motor assembly. There is no tilting or deviation in the holder, making it easier to insert the rotor shaft.

According to the fourth aspect of the present invention, the diameter of the outer peripheral edge of the tip end surface of the spring bearing is smaller than 2D, so that even if the outer ring of the ball bearing protrudes into the through hole of the holder portion. The spring receiver can bias the inner ring without being caught by the outer ring.

[Brief description of drawings]

FIG. 1 is a sectional view showing a configuration of an exemplary embodiment of the present invention.

FIG. 2 is an enlarged view showing a configuration around a spring receiver.

FIG. 3 is a sectional view showing an assembly procedure.

FIG. 4 is a cross-sectional view showing an assembly procedure.

FIG. 5 is a diagram showing a conventional example.

[Explanation of symbols]

1,63 rotor shaft 2 ball bearings Inner ring of 2A ball bearing 2 2B ball bearing 2 outer ring 3 ball bearings Inner ring of 3A ball bearing 3 Outer ring of 3B ball bearing 3 4 Spring support 5 compression springs 6 Holder part 7 End wall 8,51 Cylindrical case 9,56 magnet 10,58 coreless winding 11,59 End block 12,60 commutator 13 bush 14 brim 15,62 cap 16,61 brushes 17 holes 18 Cover member 19,57 rotor 20 casing 21, 29 Enlarged section 22 colors 23 Inclined part (first inclined part) 24 inclined part (second inclined part) 25 Large diameter part 26 balls 27, 28 contacts 30 through holes 31 shaft hole 40 jigs 41 shaft 42 base 43 hollow 52 Metal holder 53 housing 54, 55 Bearing metal

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 3J012 AB04 BB03 CB03 EB14 FB10                       HB02                 3J017 AA02 AA05 DA01 DB07                 5H605 AA00 AA08 BB05 BB19 CC01                       CC02 CC04 CC05 EA10 EB10                       EB18 EB39                 5H623 AA10 BB04 BB07 GG11 HH06                       HH10 JJ01 LL07

Claims (4)

[Claims] 1. A rotor shaft is provided with a holder portion extending from the bottom wall portion of the casing in the inward axial direction and having a through hole, and ball bearings provided at both ends of the through hole of the holder portion. And a compression spring is provided between the inner rings of both ball bearings via spring bearings, respectively, and the inner ring of at least one ball bearing is slidable in the axial direction of the rotor shaft, and the spring bearing is The shaft has a shaft hole through which the shaft is passed, and the opening of the shaft hole at the tip end that abuts the inner ring is provided with a first inclined portion, and the difference between the outer diameter of the spring receiver and the diameter of the through hole of the holder is 2A The difference between the diameter of the opening edge of the first inclined portion and the diameter of the rotor shaft on the tip end surface of the receiver is set to 2C, and A <C is set, and the compression spring causes the ball bearings to be respectively applied to the ball bearings. A motor characterized by applying a preload. 2. The motor according to claim 1, wherein the difference between the diameter of the shaft hole of the spring bearing and the diameter of the rotor shaft is 2B, and B <A is set. 3. The motor according to claim 1, further comprising a large-diameter portion, which is coaxial with the shaft hole and accommodates an end portion of the compression spring, on a rear end side of the spring receiver. 4. A second inclined portion is formed on the outer peripheral portion of the tip of the spring bearing, and the inner diameter of the outer ring of the ball bearing on the spring bearing side is 2D. 4. The motor according to claim 1, wherein the diameter is set to be smaller than 2D.