JP2003032958A - Motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor which can avoid creeping of its ball bearings, while a preload is applied to them. SOLUTION: An inner ring of ball bearings 12 is pushed into a rotary shaft 23, and an outer ring of the ball bearings is fixed to a bearing holder 11 with set screws 14 via a pressing plate 13. The bearing holder 11 is fixed to a bracket 21 with screws 26 via spacers 24 and spring washers 25, to apply a preload to the ball bearings 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to prevention of creep of an electric motor, which is a drive source of equipment, in particular, a ball bearing in which a rotating shaft is radially loaded.

[0002]

2. Description of the Related Art Conventionally, in an electric motor using a ball bearing, an appropriate pressure is applied in the axial direction in order to secure the life of the ball bearing. For this reason, a slight gap is provided between the outer ring and the bearing housing (or the inner ring and the rotating shaft) to make them loose.

When a load is applied to the output shaft in the radial direction when the electric motor is driven, a slip phenomenon occurs due to a dimensional difference between the outer diameter of the outer ring and the inner diameter of the bearing housing (or the inner diameter of the inner ring and the outer diameter of the rotating shaft), causing wear. Therefore, measures against creep were taken.

Generally, an inner ring of a ball bearing and a rotary shaft are press-fitted to each other, a slight gap is provided between an outer ring of one ball bearing and a housing to loosen the outer ring, and the outer ring is axially moved by a spring. I was under pressure.

[0005]

However, it is difficult to surely fix the ball bearing outer ring in the conventional pressurizing structure using a spring in which the inner ring is press-fitted or adhered to the rotating shaft and one outer ring is loose as in the prior art. Yes, it was not possible to completely prevent creep.

When used in an application such as a diaphragm pump in which an unbalanced load in the radial direction is applied to an electric motor, creep is particularly likely to occur.

In addition, in the both output shaft type electric motor,
If both ball bearing outer rings are fixed to the bearing housing, it is difficult to apply pressure to the ball bearings.

Therefore, it is possible to apply pressure by providing a gap between the inner ring and the rotating shaft, but this time, creep occurs between the inner ring of the ball bearing and the rotating shaft, and the ball bearing Creep could not be avoided by applying pressure to the.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide an electric motor capable of preventing creep of a ball bearing while applying pressure.

[0010]

In order to solve the above-mentioned problems, an electric motor of the present invention is an electric motor in which a rotary shaft is supported by ball bearings at both ends, and the outer ring of the ball bearing and the bearing holder are screwed while applying pressure. A bearing holder for fixing and inserting and locking the outer ring of the ball bearing, a bracket for mounting the bearing holder, a spacer thicker than the outer peripheral flange of the bearing holder, and a step between the bearing holder and the spacer. The inner ring of the ball bearing is press-fitted into the rotating shaft, the outer ring is fixed to the bearing holder via screws, and this bearing holder can be moved in the axial direction with the spacer and spring washer with respect to the bracket. It is fixed with screws so that the creep of the ball bearing can be prevented.

[0011]

In order to solve the above problems, an electric motor according to a first aspect of the present invention is an electric motor in which a rotating shaft is supported by ball bearings at both ends, and the outer ring of the ball bearing and the bearing holder are screwed while applying pressure. It is fixed and can prevent creep.

According to another aspect of the electric motor of the present invention, a bearing holder into which an outer ring of a ball bearing is inserted and locked, a bracket for mounting the bearing holder, a spacer thicker than a wall thickness of an outer peripheral brim of the bearing holder, The bearing holder and the spacer are provided with a spring washer that is pressed between the steps, and the inner ring of the ball bearing is press-fitted into the rotating shaft, and the outer ring is fixed to the bearing holder via a screw. The outer ring of the ball bearing can be fixed while applying pressure by fixing it with screws via spring washers.

Further, in the electric motor according to the third aspect of the invention, the step portion of the rotary shaft is used for press-fit positioning of the inner ring, so that the ball bearing can be accurately positioned in the axial direction.

According to a fourth aspect of the present invention, bearing holders are provided on both sides, and one bearing holder is fixed to the bracket with screws without using spacers and spring washers.
The bearing structure can be shared, and both ball bearing outer rings can be fixed with screws.

Further, even if the electric motor of the fifth aspect is a double output shaft type, creep can be prevented by fixing the outer rings of both ball bearings with screws while applying pressure.

Further, an electric motor according to a sixth aspect of the present invention is a diaphragm pump using the above-mentioned electric motor, and even when it is used in an application where a radial unbalance load is applied to a ball bearing by constantly reciprocating the diaphragm, creeping occurs. It can be prevented.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 shows a fixing structure of an outer ring of a ball bearing.

1A and 1B, 11 is a bearing holder, 12 is a ball bearing, 13 is a holding plate, 14 is a set screw,
Denoted at 15 is a brim portion, which is provided at three locations on the outer circumference of the bearing holder 11.

The outer ring of the ball bearing 12 is inserted in the inner periphery of the bearing holder 11 in a loose state, and the outer ring end surface of the ball bearing 12 is slightly protruded from the end surface of the bearing holder 11 so as to come into contact with the holding plate 13. Having received the outer ring end surface, the pressing plate 13 is fixed to the bearing holder 11 with the setscrew 14 to complete the bearing holder.

Next, the pressurizing structure of the electric motor using the above-mentioned finished bearing holder will be mainly described.

In FIG. 2, reference numeral 21 is a bracket, 22 is a stator having windings, and 23 is a rotating shaft having a rotor. 24 is a spacer, 25 is a corrugated spring washer, 2
6 is a screw. Further, FIG. 3 is an enlarged view for explaining a main part of the pressurizing structure, in which 31 is a clearance, 32 is a gap, and 3 is a clearance.
3 is a step.

First, the brackets 21 are attached to the outer circumference of the stator 22 from both sides. Then, the inner ring of the ball bearing 12 of the completed bearing holder described with reference to FIG. 1 is press-fitted to the step portion of the rotary shaft 23, and the flange portion 15 of the completed bearing holder is fixed to one bracket 21 at three positions with screws 26. Further, the inner ring of the ball bearing 12 of the other finished product of the bearing holder is press-fitted to the step portion on the opposite side of the rotary shaft 23.

Then, in order to apply pressure through the mounted bearing holder finished product, a spacer 24 and a spring washer 25 thicker than the wall thickness of the flange portion 15 of the bearing holder are used.

By the way, the bearing holder 11 and the bracket 2
A slight clearance 31 is provided in the radial direction at the insertion part with 1. The bearing holder and the bracket 21 are dimensioned so that a gap 32 can be reliably obtained in the axial direction after the inner ring is press-fitted.

Then, a spring washer 25 is provided at a step 33 between the brim portion 15 and the spacer 24, and the brim portion 1 is secured by a screw 26.
5 is fixed to the bracket 21.

The spring washer 25 is set higher than the step 33 in a free state where it is not pressed, and the screw 26 can be tightened only by the amount limited by the height of the spacer 24. Therefore, excessive pressure is not applied to the ball bearing. Absent. Further, the spring pressure is set so that the proper pressure is applied in this pressed state.

As a result, the inner races of both ball bearings are press-fitted and fixed to the rotating shaft, and the outer races of both ball bearings are fixed by screw, so that creep does not occur. Further, since the spring washer can apply an appropriate pressure, the life of the ball bearing can be secured.

It should be noted that the finished product of the bearing holder may be only one on the spring washer side. In that case, the other side may be a bracket in which the bearing holder is integrated and the outer ring of the ball bearing may be fixed.

(Embodiment 2) Embodiment 2 is an embodiment in which the electric motor of Embodiment 1 is applied to drive a diaphragm pump.

4 (a) and 4 (b), 41 is a crank support, 42 is a crank shaft, 43 is a bearing, 44 is a rubber diaphragm, 45 is an intake port, 46 is an exhaust port, and beyond that. There is a valve (not shown) to prevent backflow.

The crank support 41 fixed to the rotating shaft of the electric motor is attached in an eccentric state with respect to the center of the bearing 43 fixed to the crank shaft 42. When the rotating shaft of the electric motor rotates, the crank shaft 42 is rotated. Reciprocates. As a result, the diaphragm 44 attached to the crankshaft 42 reciprocates to suck gas from the intake port 45 and discharge it from the exhaust port 46.

As described above, since the electric motor is properly pressurized with the inner and outer races of both ball bearings fixed, even if it is used in a diaphragm pump in which an unbalanced load in the radial direction is constantly applied to the rotary shaft, creep is prevented. It can be prevented.

[0034]

As is apparent from the above embodiments, according to the inventions of claims 1 and 2, creep can be prevented because the inner ring and the outer ring of the ball bearing are fixed while applying pressure.

According to the invention of claim 3, in addition to the above claims, it is possible to easily secure the positioning accuracy of the ball bearings, so that it becomes easy to secure the proper pressurization.

According to the inventions of claims 4 and 5,
Both output shaft type bearing structures can be shared, and the outer rings of both ball bearings can be securely fixed with screws to prevent creep.

Further, according to the invention described in claim 6, creep can be prevented even when used in a diaphragm pump in which an unbalanced load in the radial direction is applied to a ball bearing of an electric motor.

As described above, since the pressurization can be applied with the inner and outer rings of both ball bearings fixed, a long-life electric motor in which creep is prevented can be obtained.

[Brief description of drawings]

FIG. 1A is a cross-sectional view illustrating a fixing structure of a ball bearing outer ring of the present invention, and FIG. 1B is a plan view illustrating a fixing structure of a ball bearing outer ring of the present invention.

FIG. 2 is a sectional view of the electric motor according to the first embodiment of the present invention.

FIG. 3 is an enlarged view of a main part of the first embodiment of the present invention.

FIG. 4A is an explanatory diagram of a diaphragm pump according to a second embodiment of the present invention. FIG. 4B is a sectional view of a diaphragm pump and an electric motor according to a second embodiment of the present invention.

[Explanation of symbols]

11 Bearing holder 12 ball bearings 13 Presser plate 14 Set screw 15 Head part 21 bracket 22 Stator 23 rotation axis 24 spacer 25 spring washers 26 screws 32 gap 33 steps 44 diaphragm

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 3H077 AA01 AA11 CC02 CC17 DD02                       DD12 EE21 EE23 EE34 FF38                       FF39                 3J012 AB02 AB04 BB01 CB01 CB03                       FB10 GB10 HB02                 3J017 AA10 CA01 DA01 DA02 DB01                       DB07 DB10                 5H605 AA05 CC04 DD09 EA11 EB39                       FF01 GG06

Claims (6)

[Claims] 1. An electric motor having a structure in which a rotating shaft is supported by ball bearings at both ends, wherein the outer ring of the ball bearing and a bearing holder are fixed with screws while applying pressure to prevent creep. 2. A bearing holder into which an outer ring of a ball bearing is inserted and locked, a bracket to which the bearing holder is attached, a spacer thicker than the outer peripheral flange of the bearing holder, and a step between the bearing holder and the spacer. The inner ring of the ball bearing is press-fitted into the rotating shaft, the outer ring is fixed to the bearing holder via a screw, and this bearing holder is fixed to the bracket with a screw via the spacer and the spring washer. The electric motor according to claim 1, wherein the motor is pressurized. 3. The electric motor according to claim 2, wherein a step portion of the rotary shaft is used for press-fit positioning of the inner ring. 4. The electric motor according to claim 2, wherein bearing holders are provided on both sides, and one bearing holder is fixed to the bracket with a screw without using a spacer and a spring washer. 5. The electric motor according to claim 1, which is a dual output shaft type. 6. A diaphragm pump using the electric motor according to any one of claims 1 to 5.