EP2201652B1 - Commutation device and electric machine - Google Patents

Description

State of the art

The invention relates to a commutation device according to the preamble of claim 1 and to an electrical machine, in particular an electric motor or a generator, according to claim 16.

In electrical engineering, a device for current application in electrical machines is referred to as a commutation device. The current application generates a current that rotates or migrates relative to the armature winding. Known commutation devices comprise a rotatably mounted on an armature shaft commutator with a plurality of circumferentially juxtaposed and electrically insulated slats, which are electrically contacted by at least two grinding elements. The constant friction between the stationary grinding elements and the rotatably driven commutator causes abrasion, usually coal dust. This is seen in the direction of rotation of the commutator in front of the grinding elements, which leads to a pre-commutation and thus to a reduction in the life of an equipped with such a commutation electrical machine. Furthermore, the resulting abrasion in air or insulating gaps between each two adjacent circumferentially slats, which can lead to short circuits.

A commutation device according to the preamble of claim 1 is already known from the document US-A-6 097 128 known.

Disclosure of the invention Technical task

The invention has for its object to propose a commutation, are avoided with the Vorkommutierungen by Abriebablagerungen. Furthermore, the object is to propose a correspondingly improved electric machine.

Technical solution

This object is achieved with regard to the commutation device having the features of claim 1 and with regard to the electrical machine having the features of claim 16. Advantageous developments of the invention are specified in the subclaims. All combinations of at least two features disclosed in the description, the claims and / or the figures also fall within the scope of the invention.

The invention is based on the idea of preventing the deposition of abrasion, in particular of coal dust, occurring during commutation, on the commutator by providing means for removing the abrasion. In this case, these means are preferably designed such that the abrasion is transported away in the radial direction to the outside. By removing the abrasion deposits on the commutator and / or on the sliding contacts and thus Vorkommutierungen be avoided, which in turn to increase the transit time of a equipped with a trained according to the concept of the invention commutation electrical Machine leads. In addition, the deposition of abrasion in insulating gaps between circumferentially juxtaposed fins and thus electrical short circuits can be avoided. It is advantageous in the invention that the means for discharging the abrasion resulting from the commutation comprise at least one voltage applied to the commutator spring, wherein the spring to avoid short circuits [] is formed of an electrically non-conductive material. The abutment of abrasion against the at least one abrasive element on the commutator is successfully prevented by the abutment of the spring on the commutator. In addition, the spring, which is designed in particular as a leaf spring, serves as a type of guide plate for removing the abrasion to the outside. []

Preferably, the spring is designed and arranged such that it extends from its fixing position in the direction of its free end in the circumferential direction of the commutator and bent in the direction of the commutator or beveled radially inwardly, thus the commutator, in particular in the radial direction, be able to act on a spring force, which ensures that the spring rests during the rotational movement of the commutator on the outer circumference and thus a slip of abrasion under the spring is avoided. The provision of at least one abrasion radially outwardly discharging spring makes it possible to integrate the means for dissipating the abrasion in the available space, whereby an electric machine with an after The commutator is formed according to the concept of the invention, does not build larger than without means for dissipating the abrasion. It is advantageous if the, in particular designed as a leaf spring, spring with its remote from the commutator end to a component of the commutation, in particular to a Schleifelementhalter (and there preferably outside a quiver for a grinding element) is set and with their free End or in the region of its free end to the commutator.

Particularly preferred is an embodiment in which the means, in particular spring, are formed from an electrically non-conductive plastic / is.

In order to successfully prevent a build-up of abrasion over the entire longitudinal extent of the commutator, an embodiment is advantageous in which the width of the means, in particular spring, corresponds at least approximately to the axial extent of the commutator or to the axial extent of the lamellae of the commutator arranged side by side in the circumferential direction. equivalent. Likewise, an embodiment is possible in which the means, preferably the spring, the commutator in the axial direction one or both sides protrude over.

In order to guarantee a clean start in the region of the free end of the means, in particular the at least one spring, an embodiment is advantageous in which the means, preferably the spring, in the region of their free, the commutator adjacent end of a curved or oblique Have / have. In addition to a clean startup is by the bevel or bend the free end in the direction of the commutator away ensures a better Abführmöglichkeit for abrasion in the radial direction. As will be explained later, an embodiment in which the means with (small) radial distance to the commutator are arranged is also feasible.

In a further development of the invention is advantageously provided that the commutation has a grinding element holder with a plurality of quivers for receiving in each case one, in particular graphite-containing, grinding element. In order to prevent the deposition of abrasion in the direction of rotation of the commutator before each grinding element, an embodiment is advantageous in which at least one grinding element, preferably each grinding element, means for removing abrasion, preferably assigned to the commutator spring assigned / is, wherein the respective means, in particular the respective spring, preferably in the direction of rotation of the commutator seen in front of the associated grinding element or in front of the grinding element holding quiver, are arranged / is. In this case, an arrangement of the means, in particular the springs, of advantage, in which they extend from the respective quiver, preferably starting from its attachment point, in the circumferential direction against the direction of rotation of the commutator.

Particularly advantageous is an embodiment in which the means, preferably the springs, in particular with the end facing away from the commutator, are fixed to the grinding element holder. It is within the scope of the development of the means, in particular the springs, integrally formed with the grinding element holder or a mounting option for the means, in particular the springs, to be provided on the grinding element holder, which makes it possible to exchange the means, in particular the springs, so that the means, in particular the springs, can be exchanged in the event of wear.

In the event that the grinding element holder is designed such that the means, in particular the springs, are releasably secured thereto, an embodiment is advantageous in which each means, in particular each spring, in two different directions positions on the grinding element holder can be fixed, ie a direction of rotation dependent attachment possibility of the springs is given to the grinding element holder. According to a preferred embodiment, the means, in particular the springs, can be fixed to the grinding element holder by clamping.

Of particular advantage is an embodiment in which the means for, in particular radial, removal of emerging during commutation abrasion of the same material are formed as the associated quiver of the grinding element holder, in which a sliding contact, in particular a carbon brush in the radial direction relative to the Commutator is adjustable. Preferably, the means of plastic, preferably of electrically non-conductive plastic, to avoid short circuits.

As mentioned above, an embodiment can be realized in which the means for removing the abrasion is formed integrally with the sliding contact holder and / or in one piece with the associated quiver, in particular in the manner of a one-piece extension. It is with regard to an efficient and cost-effective production particularly advantageous if the means are made with the associated quiver as a common injection molded part. It is particularly preferred if all quivers are formed with associated means as a common injection molded part.

In a further development of the invention is advantageously provided that the outer contour of the means are adapted to the outer contour of the rotatably arranged commutator. Preferably, the means for this purpose are formed curved on the side facing the commutator in the direction of the circumferential extent of the commutator.

As mentioned above, an embodiment can be realized in which the at least one spring rests against the outside of the commutator during rotation.

The invention also leads to an electrical machine, in particular an electric motor or a generator, with a previously described commutation device, wherein the commutator of the commutation device is arranged rotationally fixed on an armature shaft. By providing a commutation device designed according to the concept of the invention, pre-commutations are avoided, thus increasing the running time of the electric machine compared with known electrical machines.

Brief description of the drawings

• Fig. 1 einen Ausschnitt einer Kommutierungseinrichtung, bei der jedem Schleifelement Mittel zum Abführen von Abrieb zugeordnet sind,
• Fig. 2 einen Schleifelementhalter der Kommutierungseinrichtung gemäß Fig. 1, und
• Fig. 3 als Stand der Technik, der das Verständnis der Erfindung erleichtert, einen Schleifelementhalter mit einstückig mit den Köchern für Schleifelemente ausgebildeten Mitteln zum Abführen von Abrieb.

In the figures, the same components and components with the same function with the same reference numerals. Show it:

• Fig. 1 a section of a commutation device, in which each abrasive element is associated with means for removing abrasion,
• Fig. 2 a grinding element holder of the commutation according to Fig. 1 , and
• Fig. 3 As a prior art, which facilitates the understanding of the invention, a grinding element holder formed integrally with the quivers for grinding elements means for removing abrasion.

Embodiments of the invention

In the figures, the same components and components with the same function with the same reference numerals.

In Fig. 1 a commutation device 1 for an electrical machine is shown. The commutation device 1 comprises a commutator 2 for the rotationally fixed arrangement on a not shown, standing perpendicular to the drawing plane armature shaft. In the exemplary embodiment shown, the commutator 2 comprises four blades 3, 4, 5, 6 made of copper arranged next to one another in the circumferential direction. The fins 3, 4, 5, 6 are electrically connected to not shown armature windings of an anchor assembly. Between each two adjacent lamellae is an axially extending air gap 7, 8, 9, 10 for electrically insulating the lamellae 3, 4, 5, 6 from each other.

The commutator 2 is arranged inside a grinding element holder 11 which, in this embodiment, has four quivers 12, 13, 14, 15 equally spaced in the circumferential direction, for a respective grinding element 16, 17, 18, 19 (carbon brush). Each grinding element 16, 17, 18, 19 is spring-loaded radially inwardly in the direction of the commutator 2 by means of a spring, not shown, so that the grinding elements 16, 17, 18, 19 on the outer circumference of the commutator 2, more precisely on the lamellae 3, 4, 5, 6, and contact them electrically during the rotational movement of the commutator 2. The friction between the commutator 2 and the grinding elements 16, 17, 18, 19 results in abrasion 20 (coal dust). For the removal of the abrasion 20 in the radial direction to the outside means 21 for dissipating the abrasion are provided. These abrasion-removing means 21 comprise four springs 22, 23, 24, 25 which are spaced apart in the circumferential direction and in each case designed as a leaf spring made of plastic, which are detachably fixed to the grinding-element holder 11. The axial extent of the springs 22, 23, 24, 25, ie their extension into the plane of the drawing, substantially corresponds to the axial extent of the lamellae 3, 4, 5, 6. The springs 22, 23, 24, 25 extend counter to that through the Arrow indicated direction of rotation 36 of the commutator 2 in the circumferential direction of the commutator 2 and are fixed with their respective end facing away from the commutator 2 end 26, 27, 28, 29 to the grinding element holder 11. The springs 22, 23, 24, 25 are formed in the radial direction inwardly bent to the commutator 2, whereby a resilient action in the radial direction is achieved. With their respective free end 30, 31, 32, 33 are the springs 22, 23, 24, 25 on the outer circumference of the commutator 2 and the slats 3, 4, 5, 6 and lead the resulting during the rotation abrasion 20 in the radial direction to the outside.

How out Fig. 1 can be seen, the springs 22, 23, 24, 25 in the region of their respective free end 30, 31, 32, 33 slightly bent outwards to ensure a clean start.

How out Fig. 1 can be seen, each grinding element 16, 17, 18, 19, a spring 22, 23, 24, 25 assigned, which is seen in the direction of rotation 36 in front of the respective grinding element 16, 17, 18, 19 is arranged. In the event that the direction of rotation 36 of the commutator 2 is to be changed, it is possible to mount the springs 22, 23, 24, 25 to the grinding element holder 11 in such a way that they do not rotate clockwise and radially inward, as shown extend counterclockwise and radially inward, thus ensuring a discharge of the abrasion 20 radially outward.

In Fig. 2 a grinding element holder 11 is shown alone. Evident is a pointing in the drawing plane backward hollow extension 34 for receiving contacts of an electrical machine. In its front in the drawing plane area of the grinding element holder 11 is disc-shaped and has four each offset by 90 ° to each other quiver 12, 13, 14, 15 for each not shown abrasive element on. In the quivers 12, 13, 14, 15 is a respective grinding element in the direction radially inwardly on the commutator 2 federkraftbeaufschlagt.

In a central opening 35, a commutator 2 is arranged in the mounted state. In the configuration shown of the grinding element holder 11, the commutator (not shown) rotates in a clockwise direction (arrow 36).

At each quiver 12, 13, 14, 15 is designed as a leaf spring spring 22, 23, 24, 25 with its side facing away from the opening 35 end 26, 27, 28, 29 detachably fixed. The springs 22, 23, 24, 25 extend from the respective quiver 12, 13, 14, 15 in the counterclockwise direction and are formed bent inwards. Their free ends 30, 31, 32, 33 are bent radially outward in the direction of the opening 35 away, in order to ensure a clean start of the commutator 2 and thus snagging with the air gaps 7, 8, 9, 10 between the slats. 3 , 4, 5, 6 of the commutator 2 to prevent.

The externally discharged abrasion 20 falls by gravity in a region outside the commutator 2 down into the housing of the electric machine, not shown, and can be removed from time to time if necessary.

In Fig. 3 As a prior art which facilitates the understanding of the invention, a grinding element holder 11 is shown. The grinding element holder 11 comprises quivers 12, 13, 14, 15, which are distributed uniformly in the circumferential direction, for a respective grinding element 16, 17, 18, 19, not shown, (analogous to FIG Fig. 1 ). Also at the in Fig. 3 shown grinding element holder 11 is formed by the friction between the not shown for reasons of clarity, to be arranged in the central opening 35, commutator and the abrasive element abrasion. To remove the abrasion in the radial outward direction each quiver 12, 13, 14, 15 associated with means 21 for removing the abrasion. The means 21 are each formed as one piece with the associated quiver 12, 13, 14, 15 rigid extensions executed, wherein the quivers 12, 13, 14, 15 are in turn formed integrally with a base plate 37 of the grinding element holder 11. The in Fig. 3 shown grinding element holder 11 forms together with the commutator, not shown, a commutation device for an electric machine. As it turned out Fig. 3 results, the direction of rotation 36 of the commutator, not shown, runs counterclockwise. The means 21 are in the embodiment according to Fig. 3 formed as integral extensions of the quiver 12, 13, 14, 15, which extend in the circumferential direction, starting from the associated quiver 12, 13, 14, 15 opposite to the direction of rotation 36. The means 21 are formed like a ramp and taper in the direction of their free ends 38. In other words, the radial extension of the formed as extensions means 21 increases in the counterclockwise direction.

How to continue Fig. 3 results, a (lower, or radially inner) side 39 of the formed as extensions means 21 relative to an associated, radially inner quiver opening 40, 41, 42, 43 arranged radially inwardly offset, whereby a circumferentially acting barrier is formed against abrasion , whereby an (excessive) impact of abrasion on the in Fig. 3 Not shown carbon brushes is prevented.

The commutator facing sides 39 of the means 21 are curved in the circumferential direction and are spaced from the commutator, not shown, between the sides 39 and the commutator only a minimal circumferential gap with a circumferentially constant radial extent of in this embodiment 0, 5mm is formed.

Claims (12)

1. Commutation device having a rotatable commutator (2) and having at least one grinding element (16, 17, 18, 19) which makes contact with the commutator (2), wherein means (21) for discharging abraded material (20) which is produced during commutation are provided, characterized in that the means (21) comprise at least one electrically non-conductive spring (22, 23, 24, 25) which bears against the commutator (2).
2. Commutation device according to Claim 1, characterized in that the spring (22, 23, 24, 25) is in the form of a leaf spring which is bent and/or arranged in a sloping manner in the direction of the commutator (2).
3. Commutation device according to either of the preceding claims, characterized in that the means (21) are/is formed from an electrically non-conductive plastic.
4. Commutation device according to one of the preceding claims, characterized in that the width of the means (21) corresponds at least approximately to the axial extent of the commutator (2) or projects axially beyond the said commutator.
5. Commutation device according to one of the preceding claims, characterized in that the means (21) have/has a bent or sloping run-on face in the region of their/its free end (30, 31, 32, 33) which bears against the commutator (2).
6. Commutation device according to one of the preceding claims, characterized in that a grinding element holder (11) with a plurality of cartridges (12, 13, 14, 15) for accommodating in each case one grinding element (16, 17, 18, 19) is provided, and in that a spring (22, 23, 24, 25) which bears against the commutator (2) in front of the cartridge (12, 13, 14, 15) as seen in the rotation direction (36) of the commutator (2) is associated with at least one cartridge (12, 13, 14, 15), preferably each cartridge (12, 13, 14, 15).
7. Commutation device according to Claim 6, characterized in that the means (21) are/is integrally formed with the grinding element holder (11), or can be secured, in particular fixedly clamped, to the said grinding element holder.
8. Commutation device according to either of Claims 6 and 7, characterized in that the means (21) can be secured to the grinding element holder (11) in two different directional positions depending on the rotation direction (36) of the commutator (2).
9. Commutation device according to one of Claims 1 to 8, characterized in that the means (21) are formed from the same material as the associated cartridge (12, 13, 14, 15) of the grinding element holder (11), preferably from plastic.
10. Commutation device according to one of Claims 6 to 9, characterized in that the means (21) with the associated cartridges (12, 13, 14, 15) are in the form of a common injection-moulded part.
11. Commutation device according to one of the preceding claims, characterized in that the means (21) are curved in the direction of the circumferential extent of the commutator (2) on that side (39) which faces the commutator (2).
12. Electrical machine, in particular electric motor or generator, having a commutation device (1) according to one of the preceding claims, the commutator (2) of the said commutation device being arranged in a rotationally fixed manner on an armature shaft.

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