Login| Sign Up| Help| Contact|

Patent Searching and Data


Title:
NON-RECTANGULAR SEGMENT-ANGLED COMMUTATOR, APPLICABLE IN THE ROTOR OF ELECTROMOTORS
Document Type and Number:
WIPO Patent Application WO/2010/133903
Kind Code:
A1
Abstract:
The subject of the invention is a non-rectangular segment-angled commutator, applicable in the rotor of electromotors, resulting in considerable increase of the useful life of electromotors of direct current, and universal electromotors, supplied by alternating current containing commutator, compared to the solutions applied before. The commutator according to the invention consists of commutator segments, and between the said commutator segments there are gaps serving as electric separators of the commutator segments from each other. The commutator is characterized by that, the angle of the commutator segments (6) separated from each other by gaps (11) of given gap width (V) is rounded-off by a given rounding-off radius (R), and the rate of the gap width (V) and that of the rounding-off radius (R) is V / R = 1.1... 2.5. The gaps (11) between the commutator segments (6) are in given case insulated with air, or filled partly, or completely with insulating material. In one of preferred embodiment the side of the commutator segments (6) at the gap (11) is formed under the rounding-off with a given chipping-out angle (α) by slant cutting, where the rate of the gap width (V) and that of the rounding-off radius (R) is: V / R = 1.2... 2 and the rate of the gap height (M) and that of the gap width (V) is M / V ≤ 2, the chipping-out angle (α) on the side of the commutator segments (6) is α < 20°, in given case 15°. The size of the gap width of the gap (11) is in given case 0.5-0.9 mm.

Inventors:
PERESZTEGI SANDOR (HU)
Application Number:
HU2010/000054
Publication Date:
November 25, 2010
Filing Date:
May 18, 2010
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
PERESZTEGI SANDOR (HU)
International Classes:
H02K13/10; H01R39/04; H02K23/00
Foreign References:
KR20030010786A2003-02-06
SU1372433A11988-02-07
FR2753849A11998-03-27
JPS56101361A1981-08-13
RU2125758C11999-01-27
SU1332433A11987-08-23
Download PDF:
Claims:
CLAIMS:

1. Non-rectangular segment-angled commutator, applicable in the rotor of electromotors of direct current making from direct voltage, or universal electromotors supplied by alternating current, where the commutator consists of commutator segments, and between the said commutator segments there are gaps serving as electric separators of the commutator segments from each other,

characterized by that,

the angle of the commutator segments (6) separated from each other by gaps ( 1 1) of given gap width (V) is rounded-off by a given rounding-off radius (R), and the rate of the gap width (V) and that of the rounding-off radius (R) is V / R = 1.1 ... 2.5.

2. Commutator according to claim 1 characterized by that, the gaps (1 1 ) between the commutator segments (6) are insulated with air, or filled partly, or completely with insulating material.

3. Commutator according to claims 1 or 2, characterized by that, the side of the commutator segments (6) at the gap (1 1) is formed under the rounding-off with a given chipping-out angle (α) by slant cutting, where the rate of the gap width (V) and that of the rounding-off radius (R) is: V / R = 1.2 ... 2 and the rate of the gap height (M) and that of the gap width (V) is M /V < 2.

4. Commutator according to claim 3, characterized by that, the chipping-out angle (α) on the side of the commutator segments (6) is α < 20°, in given case 15°.

5. Commutator according to any of claims 1 - 4, characterized by that, the size of the gap width of the gap (1 1) is in given case 0.5-0.9 mm.

Description:
Non-rectangular segment-angled commutator, applicable in the rotor of electromotors

The subject of the invention is a non-rectangular segment-angled commutator, applicable in the rotor of electromotors, resulting in considerable increase of the useful life of electromotors of direct current, and universal electromotors, supplied by alternating current containing commutator, compared to the solutions applied before.

The rate of wear of the brush is very high, and the spark of the commutator is a regularly occurring problem with the universal series electromotors of high-speed range. In case of universal electromotors like boring machines, edge grinders, hoover motors, the size of the motor and commutator is small due to the field of use, therefore the bar-to-bar voltage is high, resulting in frequent sparks at the sharp angled segment of the commutator. A considerable part of these motors are made for high-speed range, resulting in a short useful life, so to ensure proper length of useful life causes a problem even with premium brand producers. The brush wears mainly due to the mechanical friction and abrasion, because in most of the commutators produced, there are sharp, angled segments.

The problem is the same in case of so-called commutators with air insulation, where there is no insulation between the segments of the outer diameter during production, but no attention is given here either to the formation of segment angle of commutators.

A further drawback of the known solutions is, that the depth of the insulating material, the gap depth: removed from among the segments is too big. Resulting in the fact, that the incrustant substances, the brush dust can be difficult to remove, causing short-circuit between the segments of the commutator. In the state of the art the GB 1913 06648 British patent description makes known an electric dynamo structure, which is designed in such a way, to prevent sparks due to projection at the brushes and it also insulates to a smaller extent between the plates. sectors or bars of the commutator. To achieve the set aim a solution is given according to the patent description, that the outermost edges of the mica or other layers, the layers directly adjacent with the surface of the commutator are left out. In the space between the edges of the bars one or more protective layer, for example lacquer layer are applied to maintain insulation, but the results of this solution are not entirely satisfactory.

According to the solution in the GB 1913 06648 patent description a strip, or a part of the outer edge of the commutator is left free, without protection on all sides, instead of being in close contact with the adjacent surfaces of the bars or sectors of the commutator, in spite of the insulation made on the surface of the commutator. It can be realized in such a way as well, that the thickness of the outer part of the layer is decreased, or deepened a little, or the outer corners or angles of the commutator are cut. In another case the outer strip or edge of the insulation is a tongue-like part, which can let a little due to the pressure of the brushes, and according to the patent description, all later defect, consequently forming of sparks as well can be avoided.

The US 398 3431 US patent description makes known aluminium commutators of low voltage for electromotors. The commutators have a polymeric spool, bars of aluminium alloy, placed in equal distances on its perimeter. This commutator is very useful in case of low voltage applications, when the applied or created voltage can change between 3 and 30V.

A critical characteristic of the formation of the commutator is the combination of the following: an electrocautery, and the formation of an electrolytic oxide-layer on the surface of the bars of aluminium-alloy. This combination of the steps allows the sticking of the bars of aluminium-alloy to the polymeric reel decreasing this way the electric resistance of aluminium. In addition to that the alloying metals, preferably iron can increase the conductivity of aluminium layer so balancing in a controlled way the electric resistance through the aluminium-aluminium oxide connection. The US 2005 082 937 US patent description describes a commutator for electromotors, which has a body with opposite ends. The bars of the commutator are fixed on the perimeter of the body. The structure emitting and regenerating oil is an organic part of the body and is situated at one end of the body. The structure emitting and regenerating oil is flaring outward from one end of the body, and determines a continuously curving surface of ring shape, ending in a ring end.

The commutator is built and arranged in such a way, that it can be fixed to the same tang with the structure emitting and regenerating oil, adjacent with a supporting element. The structure emitting and regenerating oil is built and arranged in such a way, that it diverts the oil, moving from the supporting element and contacting the ring surface, fathering from one end of the body, directing back the oil towards the supporting element with the

The known solutions do not provide an appropriate solution to decrease the brush wear and prevent sparks due to wear. It furthermore results in the burn-off the motor due to the metallic short-circuit between the brush-houses induced by the electric arc between the adjacent brushes. The mechanical wear of the brush can be decreased by the decrease of the extent of the shock of the commutator, but we are not dealing with it in connection with the present invention.

The spark could be decreased with increasing the insulating distance, but it can be mainly realized with commutators of greater diameter. With increasing the number of segments, the average segment voltage can be decreased. Due to the small sizes it can scarcely be realized.

On basis of the general technological knowledge of the specialty it can be stated, that nearly overall motors with commutators of sharp, angled-segments are widely spread. When working out the solution according to the invention we aimed to decrease sparks of brushes (brush sparks) as well as to decrease mechanical abrasion, resulting in increase of the useful life of electromotors.

When creating the solution according to the invention, we realized, that in case a rounding-off of suitable radius is applied at the angles of the commutator segments of electromotors of direct current and universal electromotors supplied by alternating current, containing commutator, where the rounding-off depends to a small extent on the size of the commutator and the thickness of the insulator, respectively preferably a chipping out is applied at the same time with the rounding-off, then the mechanical abrasion of the brush and the sparks resulting from the segment voltage can be decreased with a single arrangement, resulting in a considerable increase of the useful life of the electromotor.

The invention is a non-rectangular segment-angled commutator, applicable in the rotor of electromotors of direct current making from direct voltage, or universal electromotors supplied by alternating current, where the commutator consists of commutator segments, and between the said commutator segments there are gaps serving as electric separators of the commutator segments from each other. The solution according to the invention is characterized by that, the angle of the commutator segments separated from each other by gaps of given gap width is rounded-off by a given rounding-off radius, and the rate of the gap width and that of the rounding-off radius is V / R = 1.1 ... 2.5.

In one preferred embodiment of the commutator according to the invention, the gaps between the commutator segments are insulated with air, or filled partly, or completely with insulating material.

In another preferred embodiment of the commutator according to the invention, the side of the commutator segments at the gap is formed under the rounding-off with a given chipping-out angle α by slant cutting, where the rate of the gap width and that of the rounding-off radius is: V / R = 1.2 ... 2 and the rate of the gap height and that of the gap width is M /V < 2.

In a further preferred embodiment of the commutator according to the invention, the chipping-out angle α on the side of the commutator segments is α < 20°, in given case 15°.

In a further preferred embodiment of the commutator according to the invention, the size of the gap width of the gap is in given case 0.5-0.9 mm.

The solution according to the invention is furthermore set forth by the following figures:

The Fig 1 shows the general realization of an electromotor 1 supplied by direct current containing a commutator in half-view, half-section.

The Fig 2 shows a traditional rectangular segment-angled commutator in the state of the art, used generally, in side view in the section A-A of the Fig 1.

The Fig 3 shows one of the possible realizations of the commutator according to the invention with rounded-off segment-angle in side view in the section A-A of the Fig 1.

The Fig 4 shows the detail I of the Fig 3 with the rounding-off of the commutator segments 6. The commutator segments 6 are rounded-off by rounding-off radius R and there is a gap 1 1 of gap width V formed between them.

The Fig 5 shows another possible realization of the commutator according to the invention with rounded-off segment-angle and partly slant cut gaps in side view in the section A-A of the Fig 1.

The Fig 6 shows the detail II of the Fig 5 with the rounding-off of commutator segments

6 and with the partly slant cut gap 1 1 between them.

The Fig 1 shows the general realization of an electromotor 1 supplied by direct current containing a commutator in half-view, half-section. The electromotor 1 consisting of a stator 2 and a rotor 3 can be seen in the figure, with the permanent magnet 4 in the stator 2, the rotor 3 consists of a sheet pack 9 and winding 8. The commutator 10 can be found on the rotor 3, which consists of the commutator segments 6 on the commutator body 7. The commutator segments 6 have contact with the brush 5 on the stator 2, which ensure supply of voltage necessary for the rotor 3 for the functioning of the motor. The gaps 1 1 are between the commutator segments 6 serving the electric separation of the commutator segments 6 from each other.

The Fig 2 shows a traditional rectangular segment-angled commutator in the state of the art, used generally, in side view in the section A-A of the Fig 1. The commutator body 7 with the formed commutator segments 6 with the gaps 11 between them can be seen in the figure. The commutator 10 with air gaps can be seen in the figure, in which case there is no distinct insulating material in the gaps 1 1, but insulation is ensured by the air in the gap 1 1. The gap 1 1 is made either after making the commutator 10, or its creation is ensured during the manufacturing process.

The angled shape of the commutator segments 6 resulting in heavy abrasion of the brushes 5 known in the state of the art can be well seen in the figure. The rotation direction of the commutator body 7 is marked with an arrow in the figure. In order to trigger the suitable electric contact a slight tension, pressure is needed to push the brushes 5 to the commutator segments 6. As the commutator segments 6 pass along the brushes 5. the angles continuously rub the brushes 5.

In case there is no proper tension, the wear decreases here, whereas the spark chance increases, as the excentricity of a certain extent on the outer diameter of the commutator 10 can easily lift the brushes 5 and so the electric circuit is broken for a short time, and an arc, fizz is created, and coking, creation of soot can happen. It can deteriorate the electric contact between the brushes 5 and the commutator segments 6 resulting in the stopping of the motor 1 in given case. In case the brush pressure is too strong, then the sharp angled-segments cause the quick wear of the brushes 5. The Fig 3 shows one of the possible realizations of the commutator according to the invention with rounded-off segment-angle in side view in the section A-A of the Fig 1. The commutator body 7 formed with air gaps and the commutator segments 6 with the gaps 1 1 insulated with air between them can be seen in the figure. The rotation direction, of the commutator body 7 is marked with an arrow in the figure. It can be well seen in the figure, that the angles of the commutator segments 6 is rounded-off according to the invention, resulting in significantly less wear of the brushes 5. The version shown in the Fig 3 is preferably used in case of commutators of motors of smaller capacity, smaller size, high speed-range.

The Fig 4 shows the detail 1 of the Fig 3 with the rounding-off of the commutator segments 6. The commutator segments 6 are rounded-off by rounding-off radius R and there is a gap 1 1 of gap width V formed between them. The rate of the gap width V and that of the rounding-off radius R is: V / R = 1.1 ... 2.5. The usual size of the gap width V of gap 1 1 is 0.5-0.8 mm. The gap height M of the gap 1 1 is preferably M < 2 V.

The Fig 5 shows another possible realization of the commutator according to the invention with rounded-off segment-angle and partly slant cut gaps in side view in, the section A-A of the Fig 1. The commutator body 7 formed with air gaps and the commutator segments 6 with the partly slant cut gaps 1 1 insulated with air between them can be seen in the figure. The rotation direction of the commutator body 7 is marked with an arrow in the figure. It can be well seen in the figure, that the angle of the commutator segments 6 is rounded-off according to the invention, resulting in significantly less wear of the brushes 5. The partly slant cut gaps 1 1 ensure at the same time, that the brush dust can easier get out of the gaps 1 1. It is favourable in case of slower motors of lower speed range.

The Fig 6 shows the detail II of the Fig 5 with the rounding-off of commutator segments 6 and with the partly slant cut gap 1 1 between them. The commutator segments 6 are rounded-off by rounding-off radius R and there is a gap 1 1 of gap width V formed between them. The side of the gap 1 1 is formed by slant cutting in α chipping-out angle. This case the rate of the gap width V and that of the rounding-off radius R is: V / R = 1.2 ... 2. The rate of gap height M and that of the gap width V is M /V < 2, and chipping-out angle α is α < 20°, in given case 15°. This is an advantage in case of motors of greater capacity, and lower speed range, because resulting from the slant cut the brush dust can still leave the gap 1 1 at a lower speed range as well. The rounding-off further promotes this effect. The usual size of the gap width V of gap 1 1 is 0.7-0.9 mm.

The advantage of the solution according to the invention is, that it offers a suitable solution compared to known solutions to decrease the wear of the brush, and resulting sparks on basis of practical tests and experiments. Consequently the risk of the burn-off of the motor resulting from the metallic short-circuit between the brush-houses due to the wear of the brush is also considerably decreased. Resulting from the application of less sharp angled segments it happens after a much longer time. So the useful life of the motor is significantly extended.

A further advantage of the solution according to the invention is that the commutator with rounded-off angles can remove the brush dust easier. It is primarily advantageous with the direct current motors of greater capacity and lower speed range, because it makes possible for the brush dust to be removed even in case of lower speed range.

The solution according to the invention can be applied in case of commutators with air insulation both for direct current and alternating current, universal motors as well.

List of references:

1 — motor

2 - stator

3 - rotor

4 - permanent magnet

5 - brush

6 — commutator segment

7 - commutator body

8 - (rotor) winding

9 - (rotor) sheet pack

10 - commutator

1 1 - gap

R - rounding-off radius

V - gap width

M - gap height α - chipping-out angle