JP5710926B2 - Motor housing - Google Patents

Description

  The present invention relates to a motor housing.

  In small motors used for home appliances and the like, a motor housing is often formed by press-molding a steel plate or an aluminum alloy die-cast product.

  There is always a demand for smaller and lighter motors. One way to respond to this is to change the design of the motor housing. Patent Document 1 describes an industrial motor. In this motor, the housing is made of a magnesium alloy to reduce the weight.

JP-A-8-47196

  An object of the present invention is to reduce the weight of a motor housing of a small motor used for home appliances and to ensure sufficient strength despite the weight reduction.

According to a preferred embodiment of the present invention, the motor housing includes a cylindrical main body portion that holds the stator and an end bracket portion that holds the bearing of the rotor, and the main body portion and the end bracket portion are integrated with a magnesium alloy. A reinforcing rib is formed by die casting on both the main body portion and the end bracket portion , and the reinforcing rib of the main body portion extends in the axial direction. hints, reinforcing ribs of the end bracket includes a reinforcing rib extending radially, and a reinforcing rib of the annular formed in the center portion of the end bracket.

According to a preferred embodiment of the present invention, in the motor housing configured as described above, a plurality of reinforcing ribs extending in the axial direction are formed at predetermined intervals on the outer surface side of the motor housing in the main body portion, and the radial direction In the end bracket portion , a plurality of reinforcing ribs extending in the direction are formed at a predetermined interval on the inner surface side of the motor housing.

According to a preferred embodiment of the present invention, in the motor housing configured as described above, the reinforcing rib extending in the radial direction of the end bracket portion is formed starting from the annular reinforcing rib .

  According to a preferred embodiment of the present invention, in the motor housing configured as described above, the main body portion has a flange portion at an end opposite to the end bracket portion, and the reinforcing rib extending in the axial direction is provided on the flange portion. And the flange portion is traversed in the radial direction.

  According to the present invention, since the cylindrical main body portion that holds the stator and the end bracket portion that holds the rotor bearing are integrally die-cast with the magnesium alloy, the motor housing can be reduced in weight. Further, since the reinforcing ribs are formed on both the main body portion and the end bracket portion, sufficient strength can be ensured.

It is sectional drawing of the motor provided with the motor housing which concerns on embodiment of this invention. It is a perspective view of the electric blower containing the motor of FIG. It is a perspective view of the electric blower containing the motor of FIG. 1, and is seen from the angle different from FIG. It is a perspective view of a motor housing concerning an embodiment of the present invention. It is a perspective view of the motor housing which concerns on embodiment of this invention, and is seen from the angle different from FIG. It is a front view of the motor housing which concerns on embodiment of this invention. It is a front view of the motor housing which concerns on embodiment of this invention, Comprising: The state which fixed the stator inside is shown. It is sectional drawing of the vacuum cleaner main body carrying the electric blower of FIG. It is a fragmentary sectional view which shows only an electric blower mounting location in FIG.

  An embodiment of the present invention will be described with reference to FIGS. 1 to 9. The motor housing according to the present invention is used in a motor included for an electric blower in a vacuum cleaner. First, the structure of the vacuum cleaner will be described.

  The vacuum cleaner main body 1 shown in FIG. 8 is a so-called canister type, and a dust collecting container 5 can be attached to and detached from a housing 2 supported at three points by two rear wheels 3 and one front wheel caster 4. It is attached. The dust collecting container 5 includes a cyclone dust collecting unit 6 and a filter 7. A hose connection portion 8 for connecting a dust collecting hose (not shown) is provided on the front surface of the housing 2. The hose connection portion 8 communicates with the cyclone dust collection portion 6 of the dust collection container 5. A transport handle 9 is provided at the front of the housing 2.

  At the rear part of the housing 2, an electric blower 10 is installed that forms a suction airflow that flows in from a dust collection hose (not shown) and passes through the cyclone dust collection unit 6 and the filter 7. As shown in FIG. 9, the electric blower 10 includes a front fan casing 11 and a rear commutator motor 12, and a centrifugal fan (not shown) inside the fan casing 11 is rotated at a high speed by the commutator motor 12 to generate a suction airflow. Generate. The suction airflow is sucked into the fan casing 11 and a part thereof is discharged through the commutator motor 12. The air passing through the commutator motor 12 cools the commutator motor 12.

  The electric blower 10 is supported by vibration rubber support rubbers 14 and 15 on a rib structure 13 inside the housing 2 with the fan casing 11 facing upward. The support rubber 14 is a ring-shaped member having an L-shaped cross section that wraps around the corner of the fan casing 11. The support rubber 15 is a rectangular parallelepiped block-shaped member applied to the end face of the commutator motor 12, and a bearing holding portion 16 at the center of the end face of the commutator motor 12 is fitted in the center circular hole 15 a.

  As shown in FIG. 1, the commutator motor 12 has a motor housing 17. The structure of the motor housing 17 will be described in detail later. A stator 18 is fixed inside the motor housing 17. The method for fixing the stator 18 will also be described in detail later. In FIG. 1, the left side of the figure is the front end side of the commutator motor 12, and the right side of the figure is the rear end side of the commutator motor 12.

  A rotor 19 combined with the stator 18 and a commutator 20 that supplies current to the rotor 19 are fixed to a rotating shaft 21. The rotating shaft 21 is rotatably supported by bearings 22 and 23. The bearing 23 is held by a bearing holding portion 16 formed in the motor housing 17. The bearing 22 is held by a bearing holding portion formed on an end bracket (not shown) fixed to the front end of the motor housing 17.

  A pair of brush holders 24 are arranged so as to sandwich the commutator 20. Each brush holder 24 holds a carbon brush 25 pressed against the commutator 20 by a spring (not shown), and is fixed to the motor housing 17 with a single screw 26.

  Next, the structure of the motor housing 17 will be described. The motor housing 17 has a cylindrical body portion 27 that holds the stator 18 as a center, and a flange portion 28 for attaching the fan casing 11 and the end bracket (not shown) is formed at the front end of the body portion 27. An end bracket portion 29 having a bearing holding portion 16 is formed at the rear end of 27. The main body part 27, the flange part 28, and the end bracket part 29 are integrally die-cast with a magnesium alloy. Ventilation openings 30 are formed in places on the main body 27.

  The specific gravity of the magnesium alloy is 1/4 of iron and 2/3 of the aluminum alloy, and the motor housing 17 can be reduced in weight simply by adopting the magnesium alloy. Furthermore, the magnesium alloy has fluidity when melted. Utilizing the goodness, the die-cast molded product is made as thin as possible. Thereby, weight reduction can be further promoted. As the thickness of the thin portion, for example, a numerical value such as 0.8 mm can be set.

  However, if the motor housing 17 is simply thinned, the required strength is insufficient. In order to supplement the strength, reinforcing ribs are formed on both the main body portion 27 and the end bracket portion 29.

  For example, as shown in FIG. 3, a plurality of reinforcing ribs 31 extending in the axial direction of the main body 27 are formed on the main body 27 on the outer surface side of the motor housing 17. In the embodiment, the number of reinforcing ribs 31 is eight, but the number is arbitrary, and it is sufficient to set the number that can achieve the purpose of reinforcement.

  The plurality of reinforcing ribs 31 are arranged in parallel to each other and at a predetermined interval therebetween. Each of the reinforcing ribs 31 starts from the flange portion 28, but the end position is not uniform, some ends in the middle of the body portion 27, and some extends over almost the entire length of the body portion 27. Further, as shown in FIG. 5, the reinforcing rib 31 is extended so as to cross the flange portion 28 in the radial direction at the flange portion 28, and also serves to reinforce the flange portion 28. The portion of the reinforcing rib 31 has a wall thickness that is approximately twice or more than that of the other portions.

  As best shown in FIG. 6, the end bracket portion 29 is formed with a plurality of reinforcing ribs 32 extending radially inward on the inner surface side of the motor housing 17. In the embodiment, the number of the reinforcing ribs 32 is eight, but the number is arbitrary, and the number may be set to achieve the purpose of reinforcement.

  The plurality of reinforcing ribs 32 are arranged at predetermined angular intervals. An annular reinforcing rib 33 is formed at the center portion of the end bracket portion 29 so as to surround the bearing holding portion 16, and all the reinforcing ribs 32 have an end extending from the reinforcing rib 33. The portions of the reinforcing ribs 32 and 33 are approximately twice as thick or thicker than other portions.

  As described above, the reinforcing ribs 31, 32, 33 are formed on both the main body 27 and the end bracket 29, so that the motor housing 17 has a sufficient strength despite being thin as a whole. Have. Further, since the reinforcing rib 31 extends to the flange portion 28 and crosses the flange portion 28 in the radial direction, the flange portion 28 also has sufficient strength. The presence of the reinforcing ribs 31, 32, and 33 is also useful for improving the hot water flow during die casting.

  Since the reinforcing ribs 32 and 33 are formed on the inner surface side of the motor housing 17, the outer surface side of the end bracket portion 29 is flat. For this reason, the support rubber 15 can be pressed tightly against the end bracket portion 29. As a result, it is possible to prevent air leakage unintended by the designer from occurring between the support rubber 15 and the end bracket portion 29.

  The reinforcing rib on the outer surface side of the motor housing 17 is not limited to the reinforcing rib 31 extending in the axial direction of the main body 27. It may be inclined with respect to the axial direction of the main body 27, or may be a lattice pattern in which circumferential reinforcing ribs are mixed. As for the reinforcing ribs on the inner surface side of the motor housing 17, for example, another annular rib concentric with the reinforcing rib 33 is formed, and a lattice pattern is formed between the reinforcing ribs 32 in the radial direction. May be. In short, it is only necessary that the entire shape of the motor housing 17 be die-cast.

  The motor housing 17 made of a magnesium alloy die-cast product not only contributes to reducing the weight of the commutator motor 12 but also has good vibration absorption, so that the commutator motor 12 can be reduced in vibration and noise. Contribute. Further, since the magnesium alloy has good heat dissipation, cooling of the commutator motor 12 is promoted. Furthermore, since the magnesium alloy has good fluidity, even if the motor housing 17 has a complicated structure, the shape can be faithfully realized by die casting. It is economical because it can be reused without throwing away surplus parts such as runners that occur during die casting.

  In the commutator motor 12, the rotor 19 rotates at a high speed of 30,000 rpm to 40,000 rpm. Therefore, if the carbon brush 25 is not firmly held, a spark is generated at the sliding portion between the carbon brush 25 and the commutator 20, and the carbon brush 25 and the commutator 20 are quickly consumed. Therefore, the rigidity of the holding portion of the carbon brush 25 is increased as follows.

  In the body portion 27 of the motor housing 17, brush attachment portions 34 are formed at two positions that are symmetric with respect to the rear end. The brush mounting portion 34 is configured by a rectangular opening 35 through which the brush holder 24 passes. A partial region of the main body 27 including the brush attachment portion 34 is a thick portion 36 that is thicker than other regions. The thickness of the thick portion 36 is set to, for example, 1.5 mm when the thickness of the thin portion is 0.8 mm. A hole 37 for screwing the screw 26 for fixing the brush holder 24 is formed in the thick portion 36 at a position in front of the opening 35. The screw 27 is a tapping screw, and the hole 37 is a tapping pilot hole.

  In the thick part 36 surrounding the opening 35 in the thick part 36, an intermediate position between the flange part 28 and the end bracket part 29 is a front boundary. However, as shown in FIG. 4, an extended thick portion 36 a that extends to the flange portion 28 is formed on the inner surface side of the main body portion 27 so that the front end of the thick portion 36 is divided into two. For this reason, the thick part 36 including the extended thick part 36 a has a length over almost the entire length of the main body part 27. The extended thick part 36 a forms a step part 38 on the inner surface of the main body part 27.

  As described above, since the region including the brush attachment portion 34 is configured as the thick portion 36, the brush holder 24 and the carbon brush 25 are held with high rigidity, and the carbon brush 25 is less likely to vibrate and rectifies with the carbon brush 25. Generation of sparks at the sliding portion of the child 20 is suppressed. For this reason, the consumption of the carbon brush 25 and the commutator 20 is reduced, and the life of both can be extended. In particular, in the case of the embodiment, since the thick portion 36 has a length extending over almost the entire length of the main body portion 27, the rigidity is reliably improved. The presence of the thick portion 36 is useful for increasing the strength of the motor housing 17 and improving the hot water flow during die casting, in combination with the reinforcing ribs 31, 32 and 33.

  If the motor housing is a press-molded product of steel plate, it is difficult to make only the brush mounting part thick, and if you want to increase the rigidity of the brush mounting part, it is necessary to make the whole wall thick, inevitably The motor housing became heavy. On the other hand, the motor housing 17 made of a magnesium alloy die-cast product is only required to have the thick portion 36, so that the required rigidity can be ensured while being lightweight.

  Subsequently, the fixing of the stator 18 will be described. As shown in FIG. 7, the stator 18 has a substantially square outer shape, and four corners are rounded portions 18 a that match the inner diameter of the main body 27. The stator 18 is inserted from the front end of the main body portion 27 by being pushed in the axial direction of the main body portion 27. When the rounded portion 18a hits a stepped portion 38 (best shown in FIG. 4) formed on the inner surface of the main body 27, the insertion of the stator 18 reaches its limit, and the stator 18 is positioned there.

  The stator 18 is fixed by screws 39. The screw 39 presses the rounded portion 18 a of the stator 18 and fixes the stator 18. A plurality of screws 39 are arranged so as to be symmetric with respect to the center of the main body 27. In the embodiment, the screws 39 are arranged at the four corners of the stator 18, and there are two symmetrical pairs of the screws 39.

  On the inner surface of the main body 27, pockets 40 for receiving the screws 39 are formed at a total of four locations at intervals of 90 °. The pocket portion 40 extends in the axial direction of the main body portion 27, and appears on the outer surface of the main body portion 27 as a semi-cylindrical bulge portion 41 extending in the axial direction.

  A hole 42 for screwing the screw 39 is formed at the bottom of the pocket portion 40. The hole 42 extends in the axial direction of the main body 27. The screw 39 is a tapping screw, and the hole 42 is a pilot hole for tapping.

  The screw 39 is screwed into the hole 42 after the washer 43 is fitted under the neck. In a state where the screw 39 is screwed into the hole 42, the head portion of the screw 39 and the washer 43 overlap the rounded portion 18a of the stator 18, and even if the stator 18 is about to come out, the way to go is blocked. Thereby, the stator 18 is prevented from coming off. When the screw 39 is screwed to the end, the stator 18 is fastened by the step portion 38 and the washer 43. Thereby, chatter vibration between the motor housing 17 and the stator 18 is prevented. It is also possible to omit the washer 43, block the hand of the stator 18 directly with the head of the screw 39, and further tighten the stator 18.

  If the motor housing is a press-formed product of a steel plate, the stator can be fixed by caulking the motor housing, but the stator 18 cannot be fixed by caulking in the magnesium alloy motor housing 17. However, the stator 18 can be firmly fixed by using the screw 39 as described above.

  Since the screw 39 is for fixing the stator 18 by blocking the direction of the stator 18 by a washer 43 fitted to the head or the neck, consideration is given to forming a hole in the stator 18 for passing the screw 39. Is unnecessary, and the processing cost of the stator 18 can be saved. The stator 18 is inserted in the axial direction of the main body 27 with respect to the main body 27, and the screw 39 is also screwed into the hole 42 formed in the axial direction of the main body 27. Thus, it can be firmly fixed so that chatter vibration does not occur.

  At least one of the rounded portions 18a at the four corners of the stator 18 engages with a stepped portion 38 on the inner surface of the main body portion 27 formed by the extended thick portion 36a. Although the stator 18 receives a reaction force when the rotor 19 rotates, the angle of the stator 18 with respect to the motor housing 17 does not shift because the rounded portion 18a is engaged with the extended thick portion 36a.

  The embodiment has been described above by taking the commutator motor as an example, but it goes without saying that the present invention can be applied not only to the commutator motor but also to all electric motors. The scope of the present invention is not limited to the structure of the above embodiment, and various modifications can be made without departing from the spirit of the invention.

  The present invention is widely applicable to motor housings.

DESCRIPTION OF SYMBOLS 12 Commutator motor 16 Bearing holding part 17 Motor housing 18 Stator 19 Rotor 20 Commutator 21 Rotating shaft 22, 23 Bearing 24 Brush holder 25 Carbon brush 27 Main body part 28 Flange part 29 End bracket part 31,32,33 Reinforcing rib

Claims (4)

In a motor housing having a cylindrical main body portion that holds a stator and an end bracket portion that holds a bearing of a rotor,
The main body part and the end bracket part are integrally die-cast with a magnesium alloy, and reinforcing ribs are formed on both the main body part and the end bracket part by the die-cast molding ,
The reinforcing rib of the main body includes a reinforcing rib extending in the axial direction,
The reinforcing ribs of the end bracket has a motor housing, characterized in that it comprises a reinforcing rib extending radially, and a reinforcing rib of the annular formed in the center portion of the end bracket. A plurality of reinforcing ribs extending in the axial direction are formed at predetermined intervals on the outer surface of the motor housing in the main body portion, and the reinforcing ribs extending in the radial direction are provided in the motor housing in the end bracket portion. 2. The motor housing according to claim 1, wherein a plurality of motor housings are formed at predetermined intervals on the inner surface side. 3. The motor housing according to claim 1 , wherein the reinforcing rib extending in the radial direction of the end bracket portion is formed starting from the annular reinforcing rib . 4.   The main body has a flange at an end opposite to the end bracket, and the reinforcing rib extending in the axial direction extends to the flange and crosses the flange in the radial direction. The motor housing according to claim 3.

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