JP2011001939A - Electric blower - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric blower having a motor frame whose interior air is prevented from easily leaking toward a fan, whereby the suction characteristics can be improved.SOLUTION: The motor frame 2 has a frame end plate 4 having a bearing housing portion 4a in which a bearing 7 is mounted, and straightening vanes 31 that cover the frame end plate 4 are mounted to the frame 2. The straightening vanes have through-holes 32 fitted over the outer periphery of the housing portion 4a. A rotor 15 has a rotor shaft 16 extending through the bearing, bearing housing portion, and straightening vanes, and the fan 21 is held to the rotor shaft 16 while covering the straightening vanes. There is provided a sealing means 35 that is larger than the housing portion 4a and shaped annularly. The gap G between a fan base 22 of the fan 21 and an opposite straightening vane base 31a of the straightening vanes is partially narrowed by the sealing means between the housing portion 4a and the fringes of the fan 21. This prevents air inside the frame 2 from leaking toward the fan through the bearing 7 and from leaking toward the fan through the through-holes 32 fitted over the housing portion 4a.

Description

  The present invention relates to an electric blower that is built in a vacuum cleaner body of a vacuum cleaner and used to generate a suction airflow.

  An electric blower that blows air from the fan through the rectifier plate inside the case body that contains the stator and rotor, and a bearing housing of a metal case end face plate that is attached to the opening of the case body, and a synthetic resin If the air on the case body side is sucked into the fan side and leaks through the gap formed in the center of the current plate and the bearing housing is inserted, the characteristics (suction characteristics) of the electric blower are descend.

  To cope with this, an annular thin part is integrally formed at the inner edge (case body side) of the through-hole of the current plate, and the inner periphery of the thin part is utilized by utilizing the elastic deformation of the thin part. A technique in which the thin-walled portion is fitted to the bearing housing in a state where the outer periphery of the bearing housing is in close contact with the outer periphery of the bearing housing, thereby improving the sealing performance of the through holes is known (see, for example, Patent Document 1). ).

JP-A-4-183996

  However, since the case end plate is a metal press-molded product, it is extremely difficult to form the peripheral portion of the bearing housing in a perfect circle, and the peripheral portion of the bearing housing is generally formed in an elliptical shape. Therefore, even if the thin-walled portion is elastically deformed when the thin-walled portion and the bearing housing are fitted, there is a possibility that the entire inner periphery of the thin-walled portion cannot be reliably brought into close contact with the entire outer periphery of the bearing housing. Thereby, the reliability in preventing the air in the case body from being sucked into the fan side and leaking is low.

  In addition, the synthetic resin rectifying plate is thermally shrunk by the heat spreading from the stator and rotor side as the electric blower is operated. As the heat shrinks, the tightness of the thin-walled portion of the rectifying plate to the outer periphery of the bearing housing decreases. Accordingly, it is difficult to maintain the sealing performance (air tightness) at the through hole for a long period of time, and the air in the case body is sucked into the fan side and easily leaks.

  Further, a hole through which the rotor shaft of the rotor to which the fan is connected is opened in the bearing housing of the case end face plate. Therefore, when the bearing mounted in the bearing housing is not provided with a seal material, the air in the case body is sucked into the fan side through the bearing and leaks. For preventing such leakage, the sealing structure at the through hole is not effective at all. Therefore, even if the sealing performance at the fitting portion between the through hole and the bearing housing is ensured, the suction characteristics of the electric blower deteriorate due to the leakage of air passing through the bearing.

  As described above, the prior art is not sufficient to prevent the air in the case body from being sucked into the fan and leaking, and there is a problem that there is room for improving the suction performance.

  In order to solve the above-mentioned problems, the present invention has a through hole that fits to the outer periphery of the bearing housing portion in an electric motor frame including a frame end face plate having a bearing housing portion in which a bearing is mounted. A rectifying plate that covers the frame end face plate is mounted, and a fan that covers the rectifying plate is fixed to the rotor shaft of the rotor that penetrates the bearing, the bearing housing portion, and the rectifying plate, and is formed in an annular shape larger than the bearing housing portion. By the sealing means, the gap between the fan base of the fan and the rectifying plate base of the rectifying plate opposed to the fan is partially narrowed between the bearing housing portion and the peripheral edge of the fan, so that the air in the motor frame However, it is characterized in that it does not leak through the bearing to the fan side, and does not leak into the gap through the through hole fitted in the bearing housing portion.

  According to the electric blower of the present invention, the fan from the portion into the gap between the rectifying plate base and the fan base located on the downstream side of the portion where air may be sucked into the fan side from the inside of the motor frame and leaked. As a sealing means is provided to prevent the air flow toward the discharge outlet of the frame from flowing, variation in the dimensions of the bearing housing part of the frame end face plate and the flow passage of the rectifying plate fitted thereto, and thermal contraction of the rectifying plate In addition, air can hardly leak from the motor frame to the fan side even though the bearing mounted in the bearing housing can be ventilated, so that the suction characteristic can be improved.

It is a side view showing a part of the electric blower according to the first embodiment of the present invention. It is sectional drawing which expands and shows a part of electric blower of FIG. It is a top view which shows the baffle plate with which the electric blower of FIG. 1 was equipped. It is sectional drawing which expands and shows a part of electric blower which concerns on the 2nd Embodiment of this invention.

  Hereinafter, a first embodiment of the present invention will be described in detail with reference to FIGS.

  Reference numeral 1 in FIG. 1 denotes an electric blower that is built in a vacuum cleaner main body of a vacuum cleaner (not shown) and performs a dust blowing operation. The electric blower 1 includes an electric motor part M and a fan part F. The motor unit M is, for example, a commutator motor, and includes a motor frame 2, a pair of brush devices 8, a stator 11, and a rotor 15. The motor unit M may be a brushless motor. The fan part F includes a fan 21, a current plate 31, a sealing means 35, and a fan cover 41.

  The electric motor frame 2 is formed by connecting a frame body 3 and a frame end face plate 4 having a vent hole.

  The frame body 3 made by drawing a metal plate is formed in a bottomed cylindrical shape having one end opened and the other end closed by an end wall 3a, and the opening edge 3b is formed in an annular shape on the outside. It is overhanging. A first bearing housing portion 3 c is formed at the center portion of the end wall 3 a so as to protrude to the outside of the motor frame 2. The first bearing housing part 3 c is open to the inside of the frame body 3. A first bearing 5 made of a ball bearing is press-fitted and held inside the first bearing housing portion 3c, and a preload spring 6 is accommodated therein. The preload spring 6 biases the inner ring of the first bearing 5 toward the fan 21 side.

  The frame end face plate 4 made by press-molding a metal plate has a second bearing housing portion 4a at the center in the longitudinal direction. The frame end face plate 4 crosses the opening of the frame main body 3 in the radial direction, and both ends thereof are screwed to the opening edge 3b. The frame end face plate 4 has a circular ventilation hole opened between its center and both ends. The electric motor frame 2 communicates with the outside through an opening left between the frame main body 3 and the frame end face plate 4 and a vent hole of the frame end face plate 4.

  The second bearing housing part 4a is formed on the outside of the motor frame 2 so as to protrude in the opposite direction to the first bearing housing part 3c, and a second bearing 7 comprising a ball bearing is press-fitted and held therein. Has been.

  The stator 11 has a stator core having a substantially square outer shape in plan view, and a stator winding wound around the stator core. The stator 11 is fixed in the motor frame 2 with its four corners being in pressure contact with the inner surface of the cylindrical peripheral wall of the frame body 3. An in-frame air passage 12 (only one is shown in FIG. 1) is formed between the outer surface of the stator core and the inner surface of the cylindrical peripheral wall facing the stator core. An exhaust portion 13 is provided in the frame main body 3 so as to be located downstream of the in-frame air passage 12. The exhaust part 13 is composed of, for example, a plurality of exhaust holes (only one is shown in FIG. 1) located between the stator 11 and the end wall 3a and opened in the cylindrical peripheral wall. The in-frame air passage 12 communicates with the opening of the frame body 3 and the vent hole of the frame end face plate 4 located on the upstream side.

  As shown in FIG. 1, a rotor 15 has a rotor shaft 16 and an armature core 17 around which an armature winding 17a is wound and a commutator 18 to which a winding terminal of the armature winding 17a is connected. At the same time, a dustproof disc 19 is attached. The dust-proof disc 19 is used for dust-proofing the second bearing 7 and is located on the opposite side of the commutator 18 with the armature core 17 around which the armature winding 17a is wound as a rotor. It is supported by the other end of the shaft 16 and covers the second bearing 7.

  The rotor 15 is mounted in the motor frame 2 through the inside of the stator 11 by rotatably supporting both ends of the rotor shaft 16 on the first bearing 5 and the second bearing 7. ing.

  The pair of brush devices 8 are electrically insulated and attached to the frame body 3, and are provided so as to penetrate the frame body 3 in the radial direction as shown in FIG. The carbon brushes 8a included in these brush devices 8 are pressed against the outer periphery of the commutator 18 by a coil spring 8b.

  The fan 21 of the fan section F is a centrifugal type, and includes a disk-shaped fan base 22 and a disk-shaped front shroud 23 facing the fan base 22 as shown in FIG. 21 are connected by a plurality of blades 24 (only one is shown) arranged at regular intervals in the circumferential direction. These members are all made of metal, for example, aluminum. Each blade 24 is provided at right angles to the fan base 22 and the front shroud 23. These blades 24 have a plurality of caulking projections (not shown) on both side edges, and the caulking projections are inserted into the caulking holes provided in the fan base 22 and the front shroud 23, respectively. Each blade 24, the fan base 22, and the front shroud 23 are connected by caulking and crushing. A discharge port 21 a is formed in the peripheral portion of the fan 21, and a suction port 21 b is opened in the center portion of the front shroud 23.

  The fan 21 passes through the second bearing 7, the second bearing housing portion 4 a, and a central portion of a rectifying plate 31, which will be described later. The nut 25 is used for fixing. As shown in FIG. 2, the central portion of the fan base 22 has a three-layer structure, and a ring-shaped distance member 26 is sandwiched between the back surface of the fan base 22 and the inner ring of the second bearing 7. Therefore, the center portion of the fan base 22 through which the rotor shaft 16 passes and the distance member 26 are sandwiched between the inner ring of the second bearing 7 and the nut 25.

  The rectifying plate 31 is an integrally molded product of a synthetic resin, for example, a nylon resin, and is used for statically reducing the airflow discharged from the discharge port 21a of the fan 21 and guiding it to the in-frame air passage 12 of the motor frame 2. It has been. As shown in FIG. 3, the rectifying plate 31 includes a disc-shaped rectifying plate base 31 a larger than the diameter of the fan 21, and a plurality of integrally provided on the peripheral surface (upstream surface) of the rectifying plate base 31 a. An upstream side stationary blade 31b having a substantially arc shape and a plurality of downstream side stationary blades 31c (see FIG. 2) having a substantially arc shape integrally provided on the back surface (downstream side surface) of the rectifying plate base 31a are provided. ing.

  The rectifying plate 31 has a circular through hole 32 at the center. The rectifying plate 31 is disposed between the fan 21 and the electric motor frame 2 with the through hole 32 fitted to the outer periphery of the second bearing housing portion 4a, and is provided at the center of the frame end face plate 4. The frame end face plate 4 is fixed by a screw 33 passed through the screw hole. The current plate 31 covers the opening of the frame body 3 and the frame end face plate 4.

  The rectifying plate base 31a of the rectifying plate 31 faces the back surface of the fan base 22 of the fan 21, and a gap G (see FIGS. 1 and 2) is formed therebetween. The upstream stationary vane 31 b of the rectifying plate 31 is disposed around the fan 21 and faces the discharge port 21 a of the fan 21. The downstream stationary blade 31 c of the rectifying plate 31 faces the opening of the frame body 3.

  The gap G is provided on the downstream side of the leakable portion with respect to the leakable portion where ventilation from the inside of the electric motor frame 2 to the discharge port 21a side of the fan 21 is possible. Here, the leakable portion refers to a fitting portion between the outer periphery of the second bearing housing portion 4a and the through-hole 32 of the rectifying plate 31, and the second bearing 7 mounted in the second bearing housing portion 4a. Pointing. The gap G communicates with the gap S1 between the discharge port 21a of the fan 21 and the upstream stationary blade 31b surrounding the discharge port 21a.

  The fan part F includes a sealing means 35 that partially narrows the gap G between the second bearing housing part 4 a and the peripheral edge of the fan 21. The sealing means 35 includes at least one, for example, a plurality of ribs 36 integrally projecting from the current plate base 31a toward the fan base 22 facing the current plate base 31a. When the number of the ribs 36 is plural, it is preferable that the number of the ribs 36 is increased so that the labyrinth action can be surely exhibited in order to increase the sealing performance.

  Each rib 36 is formed in an annular shape as shown in FIG. 3, and has a larger diameter than the second bearing housing portion 4a. The cross section of each rib 36 in the radial direction is, for example, a semicircular shape, but it is desirable to have a flat tip surface in order to further improve the sealing performance. The ribs 36 protrude so that their tips are close to or slightly in contact with the fan base 22.

  Here, the proximity means that the rib 36 and the fan base 22 are in a non-contact state with a minute gap of less than 0.5 mm. Further, “lightly touching” refers to a state where the back surface of the fan base 22 is in sliding contact with the rib 36. This sliding contact state is that the rib 36 has a lower strength than the fan base 22 when the electric blower 1 is operated for the first time after the fan portion F is assembled with the rib 36 in contact with the rear surface of the fan base 22. The surface can be obtained by scraping with the fan base 22 of the rotated fan 21 and rubbing with the state in which the fan base 22 and the rib 36 are familiar.

  The rib 36 is provided to avoid the caulking portion so that the driving force of the fan 21 does not increase due to interference with the caulking portion of the blade 24 exposed on the back surface of the fan base 22. At the same time, in order to reduce the possibility that the ribs 36 come into contact with the fan base 22 due to the vibration of the fan 21 described later, the ribs 36 are not portions close to the discharge port 21a in the rectifying plate base 31a, but the rectifying plate base. It is provided close to the inner peripheral side of 31a.

  The fan cover 41 that guides the airflow discharged from the fan 21 to the rectifying plate 31 is made of, for example, metal, and has an air inlet 41a that faces the air inlet 21b of the fan 21 at the center as shown in FIGS. In addition, it has a stationary blade presser 41b on the periphery. The fan cover 41 is fitted to the opening edge 3 b of the electric motor unit M, and is attached to the electric motor frame 2 so as to cover the fan 21 and the rectifying plate 31. The stationary blade pressing portion 41 b sandwiches the peripheral portion of the rectifying plate 31 with the opening edge 3 b of the frame body 3.

  As shown in FIG. 2, a ring-shaped sealing material 42 is attached to the back surface of the fan cover 41 so as to surround the air inlet 41 a. The seal material 42 is made of a material having a lower strength than the metal material forming the fan 21, such as a paper material. The seal material 42 has a seal groove 42 a into which the edge of the suction port 21 b of the front shroud 23 is inserted. The seal groove 42a is formed by scraping a part of the seal material 42 at the edge of the suction port 21b by rotating the fan 21 with the edge of the suction port 21b inserted into the seal material 42. . The space between the front shroud 23 and the fan cover 41 and the suction port 21b of the fan 21 are sealed by fitting the edges of the seal groove 42a and the suction port 21b. Part of the discharged air is prevented from being sucked into the suction port 21b through the space S.

  When the motor unit M of the electric blower 1 is energized, the fan 21 is rotated together with the rotor 15, whereby the airflow is changed to the air inlet 41 a of the fan cover 41, the fan 21, the air path in the rectifying plate 31, The in-frame air passage 12 and the exhaust portion 13 are circulated in this order, and the dust blowing operation of the vacuum cleaner is performed.

  In this air blowing operation, air discharged from the discharge port 21a of the fan 21 between the upstream stationary blades 31b of the rectifying plate 31 communicates with the gap S1 between the upstream stationary blade 31b and the discharge port 21a. The gap G is negative pressure.

  However, since the gap G is sealed by the sealing means 35 including a plurality of ribs 36, the gap G is formed between the fan base 22 and the current plate 31 on the second bearing housing portion 4 a side. In addition, the negative pressure of the gap G on the downstream side of the rib 36 is unlikely to reach the gap S2 where the second bearing housing portion 4a faces. Thereby, the difference of the pressure in the electric motor flame | frame 2 and the pressure in the said space | gap S2 can be made small.

  Therefore, a part of the high-pressure air introduced into the motor frame 2 through the rectifying plate 31 passes through between the inner ring and the outer ring of the second bearing 7 and is sucked into the gap S2. When there is a gap in the fitting portion between the second bearing housing portion 4a and the through hole 32 of the rectifying plate 31 due to variations in the dimensions of the frame end face plate 4 and the rectifying plate 31 and thermal contraction of the rectifying plate 31 Even so, it is suppressed that the air is sucked into the gap S2 through the gap.

  Therefore, the air that has passed through the two leakable parts described above circulates through the gap G, and joins the air discharged from the discharge port 21a of the fan 21 in the gap S1 and is prevented from repeating circulation. . Thus, since it is difficult to circulate air in the electric blower 1, it is possible to suppress a decrease in blowing efficiency.

  At the same time, the air in the motor frame 2 is difficult to reach the fan 21 side through the second bearing 7 as described above, so that dust such as carbon powder is slightly mixed in the air in the motor frame 2. However, it can also be prevented that it enters the second bearing 7 and the life of the second bearing 7 is reduced. Therefore, the air circulation described above can be made difficult without using a high-cost ball bearing with a seal member as the second bearing 7. In addition, since the sealing means 35 is composed of the ribs 36 formed integrally with the current plate 31, there is no need for dedicated parts in order to make it difficult to circulate the air, and this can also be realized at a low cost.

  Further, the air flowing through the fan 21 is not in a continuous laminar flow state, the suction negative pressure fluctuates, the air is scraped by the blade 24, the stagnation of the air near the wall surface facing the flow path in the fan 21, It flows in a pulsating state due to generation of turbulent flow, collapse (disappearance) of turbulent flow, and the like. In response to this pulsation, the fan 21 is repeatedly deformed (vibrated) in the thickness direction. For this reason, the greater the vibration of the fan 21, the greater the associated noise.

  However, as described above, the rib 36 of the rectifying plate 31 forming the sealing means 35 is in contact with or slightly in contact with the fan base 22, so that the vibration of the fan 21 is suppressed to be small by using the rib 36 as a stopper. The Therefore, noise caused by the vibration of the fan 21 can be reduced.

  A second embodiment of the present invention will be described with reference to FIG. Since the second embodiment is the same as the first embodiment except for the components described below in FIG. 4, the same components as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment. The description thereof is omitted.

  In the second embodiment, the seal means 35 is formed of a metal seal plate 38 and a seal member 39.

  The seal plate 38 is made of a thin plate made of metal such as aluminum, has an annular protrusion 38 a, and is attached to the rectifying plate 31. The seal plate 38 forms a part of the current plate 31 and is provided by being inserted into the mold when the resin portion of the current plate 31 is formed. The protruding portion 38 a protrudes so as to be close to the fan base 22.

  The seal member 39 is made of a material such as paper having lower strength than the seal plate 38 and is fixed to the back surface of the fan base 22. The seal member 39 has a groove 39a inserted so that the protruding portion 38a bites in from the rectifying plate base 31a side. The groove 39a is formed by scraping a part of the seal member 39 by the protrusion 38a by rotating the fan 21 with the protrusion 38a inserted into the seal member 39. In this case, since the seal plate 38 is made of metal and is thin, insertability and cutting performance with respect to the seal member 39 are good. By fitting the groove 39a and the protruding portion 38a of the seal plate 38, they are slightly in contact with each other, and the gap G is partially narrowed between the second bearing housing portion 4a and the peripheral edge of the fan 21. Yes.

  Except for the configuration described above, the second embodiment is the same as the first embodiment. Also in this second embodiment, the middle of the gap G formed between the fan base 22 and the rectifying plate base 31a is sealed by the sealing means 35 including the sealing plate 38 and the sealing member 39 into which the sealing plate 38 is inserted. Therefore, on the second bearing housing part 4a side with the sealing means 35 as a boundary, a seal is formed in the gap S2 formed between the fan base 22 and the rectifying plate 31 and facing the second bearing housing part 4a. The negative pressure in the gap G on the downstream side of the means 35 is difficult to spread. Thereby, the difference of the pressure in the electric motor flame | frame 2 and the pressure in the said space | gap S2 can be made small. Therefore, as in the first embodiment, the air that has passed through the two leakable parts flows through the gap G, joins the air discharged from the discharge port 21a of the fan 21 in the gap S1, and circulates. Is suppressed from being repeated. Since it is difficult to circulate the air in the electric blower 1, it is possible to suppress a decrease in the blowing efficiency.

  DESCRIPTION OF SYMBOLS 1 ... Electric blower, 2 ... Electric motor frame, 3 ... Frame main body, 4 ... Frame end surface plate, 4a ... Bearing housing part, 7 ... Bearing, 11 ... Stator, 15 ... Rotor, 16 ... Rotor shaft, 21 ... Fan 22 ... Fan base, 21a ... Discharge port, 31 ... Current plate, 31a ... Current plate base, 32 ... Through hole, G ... Gap, 35 ... Sealing means, 36 ... Rib, 38 ... Seal plate, 38a ... Projection 39 ... Sealing member

Claims (3)

A frame main body in which a stator and a rotor are housed, and an electric motor frame having a frame end face plate that has a bearing housing portion and is attached to the frame main body;
A bearing mounted in the bearing housing portion and rotatably supporting a rotor shaft of the rotor;
A rectifying plate that has a through-hole fitted to the outer periphery of the bearing housing portion, covers the frame end face plate, is attached to the electric motor frame, and guides an airflow into the electric motor frame;
A fan cover that covers the fan and the current plate and is attached to the motor frame and guides the airflow discharged from the fan to the current plate;
A gap between the fan base of the fan and the rectifying plate base of the rectifying plate facing the fan base is formed between the bearing housing portion and the peripheral edge of the fan. Sealing means for partially narrowing;
An electric blower comprising:   The rectifying plate is a molded product made of synthetic resin, and the sealing means protrudes integrally from the rectifying plate base toward the fan base so as to come close to or slightly contact with the fan base. The electric blower according to claim 1, comprising an annular rib.   The sealing means is made of a metal sealing plate having an annular projecting portion attached to the rectifying plate and projecting toward the fan base, and made of a material having a lower strength than the sealing plate. 2. The electric blower according to claim 1, wherein the electric blower is formed of a seal member that is fixed to the base and that is inserted so that the protruding portion bites in from the rectifying plate base side.

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