JP2008125202A - Brush device for commutator motor and vacuum cleaner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact and reliable brush device which is suitable for a commutator motor where downsizing is emphasized. <P>SOLUTION: In the brush device for the commutator motor of an electric blower which has a blower function mounted to a vacuum cleaner, a brush holder box is made to serve as a cross-shaped heteromorphic tube, and a brush, a winding spring, and a lead wire are stored therein, and the lead wire is separated and protected from a motor circuit, whereby the compact brush device is obtained for a motor for a commutator, by preventing the unnecessary electric short circuit of the lead wire caused by wind pressure from a fan. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a brush device and a vacuum cleaner for a commutator motor.

  Conventionally, in an electric motor used for an electric blower, a commutator motor having two magnetic poles is often used. This electric motor has characteristics suitable for driving a blower because the rotation speed increases when the load is light and the rotation speed decreases and a high torque is generated when the load is heavy. .

Further, in order to improve the operability by making the vacuum cleaner main body small and light, the commutator motor mounted on the main body is also required to be small and light. As a means for reducing the size and weight of the commutator motor, for example, as described in Non-Patent Document 1, a high rotational speed of 40,000 rpm (40,000 min ⁻¹ ) or more per minute is set. Methods such as setting the density relatively high are employed.

  On the other hand, what is required in conjunction with the reduction in size and weight is high durability, and the life of the brush is one of the main factors that determine this. The brush device of a commutator motor constantly performs sliding contact with brush wear and transfers power, but the brush life is mechanical wear due to mechanical sliding contact between the brush and commutator. The electrical wear is affected by the spark voltage accompanying the rectification phenomenon. Mechanical wear has factors such as roughness of the surface of the commutator and unevenness of the commutator pieces as factors affecting from the commutator side. It is well known that if the surface of the commutator that slides on the brush is rough, the amount of brush wear is large, and if the unevenness of the commutator piece is large, the amount of brush wear increases due to an increased chance of the brush colliding with the commutator. In addition, as a factor affecting the increase in mechanical wear from the brush side, there is an excessive setting of the brush pressure. The brush pressing force is a pressing force that urges the brush toward the commutator. Generally, as the brush pressing force increases, mechanical wear tends to increase.

  For this reason, in order to suppress an increase in mechanical wear, it is preferable to make the surface of the commutator as smooth as possible, to set the unevenness of the commutator piece as small as possible, and to set the brush pressure as small as possible. However, if the brush pressure is too small, the brush vibration becomes excessive and the soundness of power transmission and reception is lost.Therefore, the electrical wear increases, and even if the mechanical wear is reduced, the electrical wear is reduced. It is confirmed that the wear increases and the effect of improving the brush life does not appear or rather the brush life decreases.

  The brush pressure is often thought to be related only to mechanical wear, but it has a close influence on brush vibration and can also affect electrical wear due to spark voltage conditions. The setting of the brush pressing force that suppresses the vibration of the brush and maintains a healthy sliding contact is important for improving the brush life, and consequently the durability of the commutator motor is also affected.

  By the way, mechanical springs are widely used because it is inexpensive to obtain brush pressure. There are various types of mechanical springs, and for example, there are various types of shapes such as a helical spring and a winding spring, and combinations of spring materials.

  The helical spring has a spring shape often used in a brush device. In this spring, even if the brush pressure is sufficient to maintain the soundness of the sliding contact at the initial stage of the brush, the brush pressure at the end of the brush decreases according to the spring constant. Set and realize stable sliding of the brush at the end in exchange for an increase in the initial mechanical wear. On the other hand, there is a constant pressure type spring represented by a winding spring as a spring that does not require a high initial brush pressure. The greatest feature is that a constant brush pressure can be obtained regardless of the brush length. Patent Document 1 shows a basic configuration of a brush device using the spring. A thin coiled spring is used as a spring to push the brush against the commutator or annular ring (slip ring), and a lead wire (pigtail) is placed on the upper end of the brush so as to avoid interference with the spring pressure part. It is connected to a corner and connected to a current-carrying metal fitting (simply called a terminal) that is pulled obliquely upward and attached to the end opposite to the brush. The lead wire (pigtail) drawn from the brush is a composite stranded wire in which a large number of thin conductor wires such as copper are bundled and twisted to minimize the influence on the brush pressure, and has a supple finish. In addition, the lead wire (pigtail) is long at the beginning of the brush in consideration of the shortening of the brush due to wear, and is configured to protrude outside the brush holder, so the overall brush device is large. It was something. In addition, when air cooling is performed for the purpose of cooling the rotating electrical machine, the wind pressure is applied to the brush holder, and the lead wire (pigtail) fluctuates and the winding conductor terminal of the rotating electrical machine, the structural member, etc. There were concerns about contact, and the reliability had to be lowered.

JP-A-11-178285 RM-96-28, EE-Rotary Machine Study Group “Improvement of power density of universal motor for cleaner”

  The problem to be solved is to achieve both reduction in brush wear in the initial stage and suppression of brush vibration in the final stage while achieving a reduction in size and weight of the commutator motor, and preventing the lead wire from contacting the rotating electrical machine structural member. A brush holding device for a commutator motor having high performance and high reliability is provided.

  In a brush device of a commutator motor of an electric blower, a brush, a winding spring, and a lead wire are stored in a brush holder box.

  Contact between the lead wire and the motor structural member or winding can be prevented.

  Hereinafter, examples will be described with reference to the drawings.

  A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a half cross-sectional view of an electric blower for a vacuum cleaner showing an embodiment of the present invention. The electric blower 1 includes a commutator motor 3 that drives a fan 70 and a blower unit that generates high-speed airflow. The blower unit is configured such that a fan 70 that rotates centrifugally and a diffuser 71 that recovers pressure are surrounded by a fan casing 102. A fan 70 is attached to the output shaft of the commutator motor 3, and the airflow flows from the inlet of the fan 70 as shown by the arrow in FIG. More discharged. Thus, the electric blower 1 obtains a high suction force while effectively cooling the loss on the electric motor side that occurs according to the work amount. Loss consumed in the commutator motor 3 includes iron loss and armature winding copper loss generated in the armature 30, iron loss and field winding copper loss generated in the stator 50, wind loss, shaft loss It consists of a loss of power, a friction loss due to brush sliding, and an electrical loss due to a contact voltage drop between the brush 11 and the commutator 5. Most of these are consumed as heat, but they are completely cooled by the airflow from the fan 70.

Further, the brush holder 10 is fixed to the motor housing 100 by a brush holder mounting screw 15 on the side opposite to the output shaft (rear position) of the electric blower 1. Since the electric motor is a two-pole commutator motor 3, two brush holders 10 are installed at opposite positions on the circumference of the commutator 5. Further, the brush holder 10 stores the brush 11, the winding spring 12, and the lead wire 13, and the brush holder 10 protects the lead wire 13 even when the airflow from the fan 70 passes through it. Thus, fluctuation of the lead wire 13 is prevented so as to prevent unnecessary electrical contact and short circuit.

Incidentally, as described above, the commutator motor 3 is 40,000 in order to achieve a reduction in size and weight.
It is driven at a high rotational speed of min ^-1 or higher. When the rotational speed increases, an increase in shaft vibration becomes a problem. To suppress vibration, the distance between the output-side bearing 41 and the counter-output-side bearing 40 locked to the shaft 45 is made as small as possible, and the armature. The natural vibration value as 30 is increased. For this reason, the distance between the bearings is set to be as small as possible. Correspondingly, the distance between the installation position of the brush device and the position of the winding, terminal, etc. is made as close as the insulation distance allows so It is possible to achieve both transfer and vibration reduction during high-speed rotation.

  As described above, the high-speed airflow in the electric blower 1 plays a role of cooling the commutator motor 3 that is driven while obtaining the suction force, and that the airflow also acts on the brush device as wind pressure. In view of the importance of a small and lightweight electric blower used for an electric vacuum cleaner from the viewpoint of improved operability, the brush 10 for transferring power protects the lead wire 13 in a limited space. In addition, the brush holding mechanism of this embodiment that realizes a stable sliding state works effectively in ensuring high performance and high reliability.

Next, the details of the brush device according to the present invention will be described with reference to FIGS. FIG. 2 is a perspective view showing the brush mechanism of the present invention. The brush device includes a brush holder box 20, a spring holding arm 18, a resin portion 14, a brush 11, a lead wire 13 (not shown), and a winding spring 12. The brush holder box 20 is made of a metal such as brass, and as shown in the drawing, the cross section is a cross-shaped irregular tube, in which the brush 11, the lead wire 13 (not shown), and the winding spring 12 are stored. . Further, the winding spring 12 is fixedly fixed to the brush holder box 20 by using a rivet 17 so as to coincide with the spring holding arm 18 at a lower position in the sliding direction of the winding spring 12. Next, a further description will be given with reference to FIG. FIG. 3 is a perspective view showing details of the brush mechanism of the present invention. For the purpose of preventing contact with the brush holder box 20 even when the height of the brush pressurizing position is moved due to brush wear, the winding spring 12 is disposed in the longitudinal direction of the brush holder box 20 in the longitudinal direction. A slit corresponding to the width dimension of is provided. The spring holding arm 18 is attached to the brush holder box 20 so as to surround the slit, and is fixed by a spring holding arm fixing screw 19. Further, the lead wire 13 is connected to the upper end surface of the brush 11, but the electrical connection to the terminal 16 uses the space above the brush 11 in the brush holder box 20 and not occupied by the winding spring 12. Then, it is preferable to start up to the terminal 16 and connect to the terminal 16. As a result, the brush pressurizing mechanism is not directly affected, and a compact and high-performance brush device in which the winding spring 12, the brush 11, and the lead wire 13 are stored in a small installation space can be obtained.

  FIG. 4 shows a cross-sectional view of the brush mechanism of the present invention as viewed from the A direction and a cross-sectional view as viewed from above. The A direction is the direction from A shown in FIGS. 2 and 3 and is the same as when the electric blower 1 shown in FIG. 1 is viewed from the axial longitudinal direction. First, a cross-sectional view seen from above will be described. The winding spring 12 and the brush 11 are arranged so as to form a cross and move relative to each other within the brush holder box 20. Further, the brush width Wb is set to about twice as large as the winding spring width Ws, and a brush connecting portion of the lead wire 13 is provided so as to avoid the pressure biasing range of the upper end surface of the brush 11 to thereby increase the brush. The structure is such that the lead wire 13 can be conducted from the brush 11 to the terminal 16 with little influence on the pressure mechanism. Moreover, the cross section seen from the A direction of the brush apparatus concerning this invention has shown the pressurization position of the initial stage brush and the last brush worn, and the condition of the winding spring 12. FIG. In the initial brush, the winding spring 12a presses the brush 11 against the commutator 5 with the spring sufficiently stretched, and in the final brush, the winding spring 12b follows the brush wear. From the initial stage to the final stage, the commutator 5 is pressed and urged with a constant brush pressure. As shown in the drawing, the pressure height position of the winding spring 12 changes according to the wear state of the brush, but the inner wall of the brush holder box serves as a guide guide so as not to hinder the movement. Similarly, the brush holder box 20 also serves as a guide for the brush 11.

  Further, there is a concern that wind pressure is applied to the brush holder and the lead wire 13 fluctuates and comes into contact with a winding conductor terminal, a structural member, or the like of the rotating electrical machine, and the reliability can be lowered. Therefore, by storing the brush, the winding spring, and the lead wire in the brush cage box, the brush cage can prevent the wind pressure from hitting the lead wire, so that the fluctuation of the lead wire can be prevented. Contact with a line conductor terminal or a structural member can be prevented. For this reason, it is possible to provide a highly reliable brazier.

  Next, a second embodiment according to the present invention will be described. FIG. 5 is a sectional view of the brush mechanism as viewed from the A direction according to the second embodiment of the present invention. A crescent-shaped groove was provided on the upper surface of the brush 11 along the outer circumferential surface of the winding spring 12. As a result, the brush pressure is received on the surface, and the brush 11 is more reliably urged, and the effect of improving the brush seating performance is achieved.

  FIG. 6 is a sectional view of the brush mechanism as viewed from the A direction according to the third embodiment of the present invention. The brush device was composed of a brush holder box 20, a spring holding arm 18, a resin portion 14, a brush 11, a lead wire 13, a winding spring 12, and a pressurizer 25. Here, the pressurizer 25 is disposed between the brush 11 and the winding spring 12, and the applied pressure is transmitted to the brush 11 through the pressurizer 25. The material of the pressurizer 25 is preferably a heat-resistant cushioning material such as a fluororesin because the brush device has a high temperature.

FIG. 7 is a sectional view of the brush mechanism as viewed from the A direction according to the fourth embodiment of the present invention. The pressurizer 25 is made of a heat-resistant buffer material, and a gap portion 27 is provided in a direction opposite to the terminal 16 of the pressurizer 25, and the lead wire 13 from above the brush 11 is passed through the gap portion 27. Contact interference with the winding spring 12 was avoided. As shown in the drawing, the brush 11 and the lead wire 13 are connected to the brush 11 at the upper end surface of the brush 11 so as to avoid the pressure biasing range. Even when the connection portion of the lead wire 13 is provided in the central portion of the wire, the pressing force applied by the winding spring 12 is only the pressurizer 25, so that the lead wire 13 is made to stand up to the terminal 16 using this gap portion 27. No problem if raised. Thus, the structure in which the lead wire 13 can be conducted from the brush 11 to the terminal 16 with little influence on the brush pressurizing mechanism. The upper end surface of the brush 11 is connected to the pressure biasing portion of the winding spring 12. The electrical connection to the terminal 16 is above the brush 11 in the brush holder box 20 and is occupied by the winding spring 12. It is preferable to start up to the terminal 16 using a space that is not present and connect to the terminal 16. As a result, the brush pressurizing mechanism is not directly affected, and a compact and high-performance brush device in which the winding spring 12, the brush 11, and the lead wire 13 are stored in a small installation space can be obtained.

  FIG. 8 is a sectional view of the brush mechanism as viewed from the A direction according to the fifth embodiment of the present invention. In contrast to the fourth embodiment, a crescent-shaped groove is provided on the upper surface of the pressurizer 25 so as to follow the outer circumferential surface of the winding spring 12. As a result, the brush pressure is received on the surface, and the brush 11 is more reliably urged, and the effect of improving the brush seating performance is achieved.

  The configuration / structure and mechanism of the brush device according to the present invention have been described above. In addition, although the application has been described for a commutator motor used in a vacuum cleaner, the brush apparatus according to the present invention reduces the initial brush pressure while maintaining the physique of the motor small, Since the seating property can be improved, it is needless to say that the effect does not change even if it is applied as a brush device for a general commutator motor, without being limited to the application and the number of poles of the motor.

  Further, in the first to fifth embodiments, the brush holder box 20 is assumed to be cut out, and the brush device is configured by assembling with the spring holding arm 18, but the brush holder box 20 and the spring holding arm are configured. 18 may be formed integrally. For example, it may be manufactured by pressing from a thin sheet material of brass, and it does not deviate from the gist of the present invention, and an advantage that an extra manufacturing cost can be omitted is added.

  As described above, the brush device of the present invention reduces the mechanical wear by reducing the brush pressure at the initial stage, improves the brush seating performance by suppressing the brush vibration at the final stage, and further leads. There is an advantage that it is possible to prevent contact between the motor and the structural member of the electric motor or the winding.

  In addition, there is an advantage that a compact brush device suitable for a commutator motor that places importance on small size and light weight can be obtained.

It is a half section of the electric blower for vacuum cleaners which shows the example of the present invention. It is a perspective view which shows the brush mechanism of this invention. It is a perspective view which shows the detail of the brush mechanism of this invention. It is sectional drawing seen from the A direction of the brush mechanism of this invention, and sectional drawing seen from the top. It is sectional drawing seen from the A direction of the brush mechanism which shows the 2nd Example of this invention. It is sectional drawing seen from the A direction of the brush mechanism which shows the 3rd Example of this invention. It is sectional drawing seen from the A direction of the brush mechanism which shows the 4th Example of this invention. It is sectional drawing seen from the A direction of the brush mechanism which shows the 5th Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electric blower 3 Commutator motor 5 Commutator 10 Brush retainer 11 Brush 12 Winding spring 13 Lead wire 14 Resin part 15 Brush retainer mounting screw 16 Terminal 17 Rivet 18 Spring retaining arm 19 Spring retaining arm fixing screw 20 Brush retaining Container box 25 Pressurizer 27 Gap 30 Armature 40 Anti-output shaft side bearing 41 Output shaft side bearing 45 Shaft 50 Stator 51 Field winding 55 Current supply terminal 70 Fan 71 Diffuser 100 Motor housing 102 Fan casing

Claims (12)

  In a brush device that transfers power while performing mechanical sliding contact with a commutator of a commutator motor used as a drive source of the electric blower, the brush spring that presses the brush against the commutator is a wrap spring, and A brush device for a commutator motor, wherein a brush, a winding spring, and a lead wire are stored in a brush holder box.   2. The brush device for a commutator motor according to claim 1, wherein a cross section in the radial direction of the brush cage box is a cross-shaped irregular tube.   2. The width dimension of the brush according to claim 1, wherein the width dimension of the brush is about twice the width dimension of the winding spring, and the connection portion between the lead wire and the brush is provided outside the range where the winding spring and the brush are in contact with each other. A brush device for a commutator motor.   2. The brush device for a commutator motor according to claim 1, wherein a crescent-shaped groove is provided on the upper surface of the brush so as to follow the outer circumferential surface of the winding spring.   In a brush device that transfers power while performing mechanical sliding contact with a commutator of a commutator motor used as a drive source of the electric blower, the brush spring that presses the brush against the commutator is a wrap spring, and A brush device for a commutator motor, wherein a brush, a winding spring, a lead wire and a pressurizer are stored in a brush holder box.   6. The brush device for a commutator motor according to claim 5, wherein a cross section in the radial direction of the brush cage box is a cross-shaped irregular tube.   6. The width dimension of the brush according to claim 5, wherein the width dimension of the winding spring is approximately twice the width dimension of the winding spring, and the connection portion between the lead wire and the brush is provided outside the range where the winding spring and the brush are in contact with each other. Brush device for commutator motor.   In Claim 5, the said pressurizer is arrange | positioned between the upper surface of a brush, and a winding spring, The crescent-shaped groove | channel was provided in the upper surface of a pressurizer so that the outer-diameter circumferential surface of a winding spring may be provided. A brush device for a commutator motor.   6. The brush device for a commutator motor according to claim 5, wherein the pressurizer is made of a heat-resistant cushioning material.   6. The brush device for a commutator motor according to claim 5, wherein the pressurizer is formed of a heat-resistant buffer material, a gap is provided below the pressurizer, and a lead wire is passed through the gap.   11. The brush device for a commutator motor according to claim 10, wherein a crescent-shaped groove is provided on the upper surface of the pressurizer along the outer circumferential surface of the winding spring. In a vacuum cleaner having a brush device that transfers power while performing mechanical sliding contact with a commutator of a commutator motor used as a drive source of an electric blower,
A vacuum cleaner, wherein a brush spring for pressing a brush against a commutator is a winding spring, and the brush, the winding spring, and a lead wire are stored in a brush holder box.

Images