JPH0715323Y2 - Electric motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a driving electric motor such as a cross flow fan installed in an indoor unit of an air conditioner.

(Prior Art) In recent years, in the cross flow fan as described above, an attempt has been made to downsize the device by directly connecting the rotor of the DC brushless motor to the fan rotor. A specific example of such a device is described in, for example, Japanese Utility Model Laid-Open No. 61-178095, and FIG. 6 shows the structure of the device. In the figure, 80 is a fan rotor of a cross flow fan, and a rotor 83 having a ring-shaped permanent magnet 82 is fixedly attached to one side plate 81 of the fan rotor 80. On the other hand, a cylindrical fixed support shaft 85 is erected on the support frame 84 facing the side plate 81, and a stator 86 is fixed to the outer periphery of the fixed support shaft 85 on the tip end side.
The outer periphery of 86 is surrounded by the permanent magnet 82.
The fan rotor 80 has a rotary support shaft 8 at the axial center positions of both ends thereof.
7 and 88 are respectively provided upright and rotatably support these rotary support shafts 87 and 88 through bearings 89 and 90.

By the way, in the above apparatus, since the fixed support shaft 85 is a hollow cylindrical body and the rotation support shaft 87 is configured to penetrate the inside of the fixed support shaft 85, for example, the outer shape of the fixed support shaft 85 becomes large. , The stator 86 and the rotor 83 have to be successively increased in diameter, which causes a problem that the size cannot be sufficiently reduced.

Therefore, the applicant first proposed a device having the following configuration. That is, on the fixed surface in the indoor unit of the air conditioner, a fixed shaft extending through the inside of the rotor connected to the fan rotor to the fan rotor side is erected, and the fixed shaft surrounded by the rotor. By fixing the stator to the position of the middle part in, and providing a bearing in the connecting portion to the fan rotor in the rotor by press-fitting the bearing, and inserting the tip side of the fixed shaft into this bearing, The fan rotor is rotatably supported (Japanese Patent Application No. 62-818).
See No. 70).

(Problems to be solved by the invention) By the way, in a configuration in which the fixed rotor supports the fan rotor and the rotor, when the fixed shaft is supported through one bearing, the smaller the shaft diameter, Since the relative allowable eccentricity becomes large, the weight of the crossflow fan, the motor, etc. easily causes eccentricity, which causes a problem of large vibration.

Therefore, it is conceivable that two bearings are provided so as to be separated from each other in the axial direction to support them, but in this case, there are the following problems. In other words, the bearing has a play between the inner sphere and the raceway surface, which causes noise during rotational driving. In order to reduce this noise, it is necessary to have a structure in which a preload is applied, but in the above, a spring washer or the like is arranged as a preload applying member adjacent to each of the two bearings, and the seat surface of this spring washer is Since it is necessary to form the bearing housing portion at a location, the shape of the bearing housing portion in the casing becomes complicated, and as a result, the size cannot be sufficiently reduced.

On the other hand, in order to provide axial positioning of the rotor with respect to the stator, in the structure in which the fixed shaft tip is inserted into and supported by the bearing fixed to the rotor side as described above, the fixed shaft is provided with a stepped portion. By abutting the side surface of the bearing on
Restrict the position in the contact direction. In this state, noise is generated due to withdrawal in the anti-contact direction or repeated contact / separation operation of the bearing from the step during rotational driving. It becomes necessary to dispose a movement restricting member in the abutting direction, which also makes it impossible to sufficiently simplify the structure and reduce the size.

The present invention has been made in view of the above, and an object thereof is to provide an electric motor capable of reducing noise with a simpler structure which can be downsized.

(Means for Solving the Problems) Therefore, the electric motor according to the first aspect of the present invention is the rotor 3
The casing 4 is provided with a bearing accommodating chamber 14 extending along the axis thereof, and the outer ring of the first radial ball bearing 12 is press-fitted into the bearing accommodating chamber 14 at one end thereof while the bearing accommodating chamber is accommodated at the other end thereof. The second radial ball bearing 13 is mounted so that its outer ring is in a clearance fit state with respect to the inner circumference of the chamber 14, and the above-mentioned bearings 12, 13 are also mounted.
A spacer 31 is provided between the bearings 12 and 13 and the spacer 31 in a clearance fit state so as to contact the inner ring side surface of the rotor 3. The second bearing 13 is supported between the second bearing 13 and the vertical end surface portion 32 of the bearing housing 14 on the side opposite to the first bearing 13 with respect to the second bearing 13. The member 33 is interposed, and the elastic force of the elastic member 33 is transmitted from the outer ring, the ball, and the inner ring of the second bearing 13 to the inner ring, the ball, and the outer ring of the first bearing 12 through the spacer 31. This is characterized in that both bearings 12 and 13 are pressurized.

In the electric motor according to the second aspect, the permanent magnet 6 is provided along the inner peripheral surface of the cylindrical portion 5 of the casing 4 of the rotor 3.
While facing the permanent magnet 6, the stator 27 is provided.
A step 34 is formed on the fixed shaft 20 with which the side surface of the inner ring of the first bearing 12 on the side opposite to the spacer is in contact, and in the state of contact with the step 34 of the first bearing 12, It is characterized in that the axial center of the permanent magnet 6 is located closer to the tip side of the fixed shaft 20 than the axial center of the stator 27.

(Operation) In the electric motor according to the first aspect, the elastic reaction force of the elastic member 33, which has been elastically deformed, acts on the outer ring of the second bearing 13, which acts on the second bearing 13 and the inner sphere and the raceway. It acts as a preload in a state where a relative displacement between the inner and outer races, which corresponds to the play with the surface, is generated. In addition, this preload is
It acts on the inner ring of the first bearing 12 from the bearing 13 via the spacer 31,
With respect to the first bearing 12, the same preload acting state as that of the second bearing 13 is applied in the state where the relative displacement between the inner and outer rings in the axial direction is generated. Therefore, a rotating state in which noise is reduced is obtained, and in the above, the bearing housing chamber 14 is provided with the elastic member 33.
Since it can be configured with a simple shape having only one seat surface for, the size can be further reduced.

In the electric motor according to the second aspect, the first bearing
Since the axial center of the permanent magnet 6 is located closer to the tip end of the fixed shaft 20 than the axial center of the stator 27 when the 12 is in contact with the step 34, Due to the magnetic attraction force acting on the stator 27 from 6, an axial force for matching both center positions, that is, a force for pressing the first bearing 12 in the contact direction with the step 34 is generated. Therefore, the side surface of the first bearing 12 opposite to the step 34 is pulled out in the opposite contact direction, or the step is driven during rotation driving.
It is not necessary to provide a movement restricting member for preventing noise due to repeated contact and separation operations with respect to 34, and therefore, a simpler configuration can be achieved, and downsizing can be achieved.

(Example) Next, a specific example of the electric motor of the present invention will be described in detail with reference to the drawings.

FIG. 5 shows a structure of one side plate 2 side of a fan rotor 1 of a cross flow fan installed in an indoor unit of an air conditioner, which is constructed as a DC brushless motor by an electric motor according to an embodiment of the present invention. The fan rotor 1 is driven. That is, in the figure, 3 is a rotor of the DC brushless motor,
The substantially cup-shaped casing 4 of the rotor 3 includes four arc-shaped permanent magnets 6 ... 6 along the inner peripheral surface of the cylindrical portion 5.
Are fixed circumferentially. On the vertical surface 7 of the casing 4 on the fan rotor 1 side, a joint boss 9 having a cylindrical bulging portion 8 projecting toward the fan rotor 1 side is centrally fixed. On the other hand, on the side plate 2 of the fan rotor 1, a vibration-proof coupling body 10 made of synthetic rubber or the like is fixed on the center side thereof, and the bulging portion is formed in the axial center through hole of the vibration-proof coupling body 10. The rotor 3 is assembled to the fan rotor 1 by press-fitting 8.

At the axial end of the vertical surface 7 of the casing 4,
A short cylindrical bearing accommodating portion 11 is formed by bending on the side opposite to the fan rotor. The first bearing 12 is provided in the bearing accommodating portion 11 and the fan rotor is coaxial with the bearing accommodating portion 11. In the bulging portion 8 extending to the 1 side, the first bearing
A second bearing 13 having the same shape as that of the bearing 12 is provided, and the bulging portion 8 and the bearing housing portion 11 form a bearing housing chamber 14. The mounting structure of the bearings 12 and 13 will be described later, but each of the bearings 12 and 13 is a rolling type radial ball bearing in which a plurality of balls are provided between the inner and outer rings.

On the other hand, reference numeral 15 in the figure denotes an end bracket, which is composed of a vertical surface 16 and a short surrounding wall 17 extending from the peripheral edge thereof toward the fan rotor in the axial direction. The peripheral edge of the lower half of the end bracket 15 in the drawing is fitted into the fitting groove formed in the frame 18 of the indoor unit, and the motor cover 19 is covered from above so that the motor cover 19 is screwed to the frame 18. By doing so, the end bracket 15 is positioned in a state where the peripheral side of the upper half thereof is also fitted in the fitting groove formed in the motor cover 19, and is fixed in the indoor unit by receiving the pressing force by the screw fastening. Has been done.

A fixed shaft 20 is provided at the center of the end bracket 15 so as to extend therethrough in the axial direction. The fixed shaft 20 includes a portion that intersects with the vertical surface 16 of the endbukerat 15 and a contact surface between the frame 18 and the motor cover 19 on the rear end (right end in the figure) side that penetrates the end bracket 15. An annular groove is formed at each position, and vibration damping rings 21 and 22 made of an elastic body such as synthetic rubber are wound around these annular grooves. The fixed shaft 20 is fixed to the end bracket 15 and the frame 18 via the vibration isolation rings 21 and 22. That is, at the axial center end of the vertical surface 16 of the end bracket 15 and the vibration-proof ring fixing plate 23 screwed to the end bracket 15, there is formed a bending portion that forms a fitting groove surrounding the fixed shaft 20. Assembling is performed by fitting the outer peripheral side of the left vibration isolation ring 21 into this fitting groove, and the outer peripheral side of the right vibration isolation ring 22 is connected to the frame.
Assembly is carried out by fitting the fitting groove into the fitting groove formed in the motor cover 19 and the motor cover 19. The above-mentioned vibration-damping rings 21 and 22 have a slightly larger shape than the annular groove of the fixed shaft 20 and the fitting groove on the outer peripheral side, and thus in the above-mentioned assembled state, they are in a press-fitted state to generate an elastic restoring force, As a result, a fixed mounting state is provided in which the positional deviation does not occur at two locations separated from the fixed shaft 20.

Then, the bearing insertion portion 25 on the front end (the left end in the drawing) side of the fixed shaft 20 is inserted into the first and second bearings 12 and 13 described above, so that the fixed shaft 20 allows the rotor 3 to rotate. And the fan rotor 1 are rotatably supported, and the outer circumference of a stator 27 fixed to an intermediate shaft portion 26 of the fixed shaft 20 having a diameter larger than that of the bearing insertion portion 25 is attached to the rotor 3
Of the permanent magnets 6 ...

FIG. 1 shows an enlarged view of the rotation support portion of the rotor 3 and the fan rotor 1 on the tip side of the fixed shaft 20. As shown in the figure, the vertical surface 7 of the casing 4 is provided with tongue-shaped projections 28 ... There is. These are for positioning the joint boss 9, and the outer periphery of the face plate portion 29 of the joint boss 9 is fitted between the tongue-shaped projections 28, 28 to fix the face plate portion 29 to the vertical surface 7. The bulging portion 8 of the joint boss 9 is concentrically assembled with the casing 4.

The inner diameter of the bearing accommodating portion 11 of the casing 4 is set to be slightly smaller than the outer diameter of the first bearing 12 arranged therein, so that the first bearing 12 is inserted into the bearing accommodating portion 11. It is fixed in the state of the sea bream by press-fitting. On the other hand, the inner diameter of the bulging portion 8 is set to be slightly larger than the outer diameter of the second bearing 13 arranged inside the bulging portion 8.
It is installed in a state where it can be moved in the axial direction. A ring-shaped spacer 31 made of a synthetic resin material as shown in FIG. 2 is arranged between the bearings 12 and 13. Further, between the vertical end surface portion 32 formed by slightly bending the tip of the cylindrical bulging portion 8 toward the center and the second bearing 13, the wave shown in FIGS. 3 and 4 is formed. A spring washer 33 formed by molding a plate into a ring shape is arranged. The spring washer 33 has inner and outer dimensions that make contact with the outer ring of the second bearing 13, and the inner diameters of the bearings 12, 13 and the spacer 31 are larger than the outer diameter of the bearing insertion portion 25 of the fixed shaft 20. It has a slightly larger size. Further, the thickness of the spacer 31 is set so that both ends thereof contact only the inner rings of the bearings 12 and 13.

In assembling the rotation support portion having the above-described configuration, first, the first bearing 12 is press-fitted into the bearing housing portion 11 of the casing 4. Then, the bearing inserting portion 25 of the fixed shaft 20 is inserted into the first bearing 12, and then the spacer 31 and the second bearing are inserted into the bearing inserting portion 25 protruding from the first bearing 12.
13. After sequentially mounting the spring washers 33, the joint boss 9 is covered, the joint boss 9 is positioned as described above, and spot welded to the vertical surface 7 of the casing 4, for example. In this assembled state, both end surfaces of the spacer 31 contact the inner ring side surfaces of the bearings 12 and 13, respectively, and the spring washer 33 is deformed in a predetermined axial direction, and the elastic reaction force thereof causes the second bearing 13 to move. Of the inner ring and the outer ring relative to each other in the axial direction of the second bearing 13 as shown in FIG.
Preload is applied without play between the inner ball and the raceway surface. Further, this preload is applied to the first bearing 12 via the spacer 31.
Acting on the inner ring of the first bearing 12, and also in the first bearing 12, an axial relative displacement occurs between the outer ring fixed by press fitting into the bearing housing portion 11 and the inner ring, and the inner ball and the orbit. The same preload as that of the second bearing 13 acts in the state where there is no play with the surface.

Further, in the above-mentioned assembled state, the step 34 between the bearing insertion portion 25 on the tip side of the fixed shaft 20 and the intermediate shaft portion 26 having a larger diameter than this is formed.
Since the right side surface of the inner ring of the first bearing 12 comes into contact with the above, the rightward movement of the rotor 3 and the fan rotor 1 is restricted. By the way, when there is a deviation between the axial center positions of the permanent magnet 6 of the rotor 3 and the stator 27,
Due to the magnetic attraction force acting on the stator 27 from the permanent magnet 6, an axial force for matching both center positions is generated. In the above device, the inner ring side surface of the first bearing 12 has the step 34
At the position where the permanent magnet 6 comes into contact with
The stator 27 is positioned slightly closer to the fan rotor 1 side than the center position of the stator 27. Therefore, in this assembled state, a force for pressing the first bearing 12 in the contact direction with the step 34 is applied.

As shown in FIG. 5, a circuit board 36 having a control circuit for the DC brushless motor is arranged in a space radially inward of the surrounding wall 17 of the end bracket 15. On this circuit board 36, other than the Hall element 37 as a magnetic field detection element and the power transistor 38, electronic components such as a capacitor, a resistor, and a control IC, which are not shown, are mounted. Of these electronic components, Tall things such as power transistors 38 and capacitors are laid sideways to mount compactly in a narrow space, and among the above electronic components, the power transistor 38, which generates a large amount of heat, is the outer periphery of the circuit board 36. It is mounted on the edge side and is attached using a spring clip 39 so as to be in close contact with the vertical surface 16 of the end bracket 15. That is, the end bracket 15 is configured to also function as a heat dissipation plate for the power transistor 38.

Next, the operating state of the fan device having the above configuration will be described.

The stator 27 extends radially and is coiled.
It has 40 wound six salient poles, and the Hall element 37 is arranged so as to be located on the outer peripheral side of each of the three adjacent salient poles. These Hall elements 37, 37 detect changes in the magnetic field strength from the permanent magnet 6 depending on the rotational position of the rotor 3. Then, in response to the detection signal, the control IC sequentially generates signals for energizing each coil 40, which periodically controls the energization of each coil 40 and generates a rotating magnetic field on the stator 27 side. It The rotating magnetic field drives the rotor 3 to rotate together with the fan rotor 1.

Then, during such rotational driving, as described above, the internal play is removed from the first and second bearings 12 and 13,
Since the preload is maintained in the applied state, the generation of noise is reduced, and the operating state with lower noise can be maintained. Further, in the case where two bearings that are spaced apart from each other in the axial direction are press-fitted together in the bearing housing chamber, for example, it is difficult to apply proper preload to each of them, and an excessive preload is applied. Will decrease the life of the bearing.
By properly dimensioning, it is possible to simultaneously apply proper preload to the two bearings 12 and 13, which facilitates adjustment and further improves the reliability of the bearings. There is.

Further, in the above, the magnetic attraction force acting from the permanent magnet 6 to the stator 27 exerts a pressing force in the contact direction of the bearing 12 to the step 34, thereby preventing the rotor 3 from moving in the anti-step direction. Therefore, it is possible to prevent noise due to repeated contact / separation operations with respect to the step 34 at the time of rotational driving with a simple configuration in which it is not necessary to provide a movement restricting member in this direction. Further, in the above device, vibrations caused by the runout of the fan rotor 1 during rotational driving are respectively interposed between the rotor 3 and the fan rotor 1 and between the fixed shaft 20 and the indoor unit frame 18. Anti-vibration coupling body 10 made of elastic body,
Since it is damped by the vibration isolation rings 21 and 22, it can be configured as an indoor unit with lower noise.

In the above, the DC brushless motor type electric motor for driving the cross flow fan is described as an example.
The invention can be applied to other types of electric motors.

(Effect of the Invention) As described above, in the electric motor according to the first aspect of the present invention, it is possible to apply the preload to the two bearings arranged in the bearing housing chamber simultaneously by the elastic member and the spacer. It is possible, the number of additional parts is small, and the bearing storage chamber can be configured with a simple shape, so that the size can be further reduced.

In the electric motor according to the second aspect of the present invention, the magnetic attraction force acting on the stator from the permanent magnet causes a force to press the first bearing against the step of the fixed shaft. It is not necessary to provide a movement restricting member for preventing noise due to repeated contacting / separating operations, and therefore, a simpler configuration can be achieved and downsizing can be achieved.

[Brief description of drawings]

FIG. 1 is a partially enlarged sectional view of a main part of a fan device constructed by applying the present invention, FIG. 2 is a sectional view of a spacer in the fan device, and FIG. 3 is a plan view of a spring washer in the fan device. 4, FIG. 4 is a view taken along the line IV-IV in FIG. 3, FIG. 5 is an assembled sectional view of one side plate side of the fan device, and FIG. 6 is a schematic front view of a conventional device. 3 ... Rotor, 4 ... Casing, 5 ... Cylindrical part, 6 ...
… Permanent magnets, 12 …… First bearing, 13 …… Second bearing, 14 ……
Bearing housing chamber, 20 …… fixed shaft, 27 …… stator, 31 …… spacer, 32 …… vertical end face, 33 …… spring washer (elastic member),
34. Step.

Claims (2)

[Scope of utility model registration request] 1. A casing (4) of a rotor (3) is provided with a bearing accommodating chamber (14) extending on the axis thereof, and the bearing accommodating chamber (14) has a first radial ball at one end thereof. Bearings (12)
While press-fitting the outer ring of the bearing, the bearing housing chamber (14) is attached to the other end.
Install the second radial ball bearing (13) so that its outer ring fits tightly against the inner circumference of the
A spacer (31) abutting against the inner ring side surface is provided between (13), and the fixed shaft (20) is loosely fitted to each of the bearings (12) (13) and spacer (31). While the rotor (3) is rotatably supported by being inserted in the state, the vertical end face portion (32) on the side opposite to the first bearing and the second bearing (13) in the bearing storage chamber (14) and the first An elastic member (33) that abuts the outer ring side surface of the second bearing (13) is interposed between the second bearing (13) and the elastic force of the elastic member (33) is applied to the second bearing (13). ) Outer ring, sphere, and inner ring through the spacer (31) to the inner ring, sphere, and outer ring of the first bearing (12), thereby applying pressure to both bearings (12) (13). An electric motor characterized in that 2. A permanent magnet (6) is arranged along the inner peripheral surface of a cylindrical portion (5) of a casing (4) of the rotor (3), while facing the permanent magnet (6). And a stator (27) is disposed thereon, and the fixed shaft (20) is provided with a step (34) with which the side surface of the inner ring of the first bearing (12) on the side opposite to the spacer is abutted. In the state where the step (34) is in contact with the step (34), the axial center of the permanent magnet (6) is located closer to the tip side of the fixed shaft (20) than the axial center of the stator (27). The electric motor according to claim 1, wherein the electric motor is configured to be located at.