EP2201652A1

EP2201652A1 - Commutation device and electric machine

Info

Publication number: EP2201652A1
Application number: EP08786295A
Authority: EP
Inventors: Daniel Klumpp; Erwin Sinnl; Anita Seebacher
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2007-09-17
Filing date: 2008-07-22
Publication date: 2010-06-30
Anticipated expiration: 2028-07-22
Also published as: US20100244620A1; JP2010539881A; CN101803126B; DE102008002030A1; WO2009037027A1; JP5361890B2; US8513852B2; CN101803126A; EP2201652B1

Abstract

The invention relates to a commutation device (1) having a rotatable commutator (2) and at least one grinding element (16, 17, 18, 19) contacting the commutator (2). According to the invention, means (21) for removing abrasion debris (20) occurring during commutation are provided. The invention further relates to an electric machine having a commutation device (1) of said kind.

Description

description

title

Commutation device and electric machine

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 include a rotatably seated on an armature shaft commutator with a plurality of circumferentially arranged side by side 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. DISCLOSURE OF THE INVENTION Technical Problem

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.

Of particular advantage is an embodiment in which the means for discharging the resulting during commutation wear comprise at least one voltage applied to the commutator spring, wherein the spring is preferably formed of an electrically non-conductive material to avoid short circuits. 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. As will be explained later, an embodiment with not applied to the commutator means is feasible.

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 start, the bevel or bending Movement of the free end in the direction of the commutator away ensures a better Abführmöglichkeit for the 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 development of the invention, it is advantageously provided that the commutation device has a grinding element holder with a plurality of pits for accommodating one, in particular graphite-containing, grinding element. In order to prevent the deposition of abrasion in the direction of rotation of the commutator in front of each grinding element, an embodiment is advantageous in which at least one grinding element, preferably each grinding element, means for removing abrasion, preferably associated with 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 of the springs, in which they extend starting from the respective quiver, preferably starting from its attachment point, in the circumferential direction counter to the direction of rotation of the commutator.

Particularly advantageous is an embodiment in which the means, preferably the springs, in particular with the end remote from the commutator, are fixed to the grinding element holder. It is within the scope of the development, the means, in particular the springs, integrally formed with the grinding element holder or a fastening tion possibility for the means, in particular the springs to provide on the grinding element holder, which allows an exchange of the means, in particular of the springs, so that the means, in particular the springs, can be replaced 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 comminuted abrasion from the same material are formed as the associated quiver of Schleifele- ment holder, in which a sliding contact, in particular a carbon brush in the radial direction relative is adjustable to the commutator. 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.

In order to allow optimum removal of abrasion arising during operation of the commutation device in the radial direction to the outside, an embodiment is preferred in which the means, in particular in the region of their free end, are formed like a ramp, wherein the ramp formed preferably in the direction of each adjacent or associated quiver increases. As a result, the abrasion particles in the direction of lying outside the commutator, extending in the radial direction, quiver outer wall are thrown or passed.

As mentioned above, an embodiment can be realized, in which the means, in particular the at least one spring, rests on the outside of the latter during rotation of the commutator. In particular, in one embodiment in which the means are not formed as a spring, that is not elastic, but rigid, an embodiment is preferred in which a gap extending in the circumferential direction is formed between the means and the commutator. In this case, an embodiment can be realized in which the width Extension of the gap in the circumferential direction is at least approximately constant and minimal. However, it is also an embodiment feasible, in which the gap width decreases toward the free end of the, preferably ramp-like, means in the circumferential direction counter to the direction of rotation of the commutator.

It is therefore not only an embodiment with at least one spring comprehensive means for dissipating abrasion feasible, but especially for cost reasons and to facilitate assembly and an embodiment with rigid means per se, which are preferably integrally formed with at least one further component of the commutation, to avoid a separate installation of the funds.

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

In the figures, the same components and components with the same function with the same reference numerals. Show it: 1 shows a section of a commutation device, in which each grinding element is associated with means for removing abrasion,

2 shows a grinding element holder of the commutation device according to FIG. 1, and

Fig. 3 shows an alternately formed 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 disposed within a grinding element holder 11, which in this embodiment has four uniformly circumferentially spaced quivers 12, 13, 14, 15 for each 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.

As can be seen from Fig. 1, 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.

As can be seen from Fig. 1, each grinding element 16, 17, 18, 19, a spring 22, 23, 24, 25 associated with, as 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 On 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, an alternatively trained Schleifelement- holder 11 is shown. The grinding element holder 11 comprises quivers 12, 13, 14, 15, distributed uniformly in the circumferential direction, for a respective grinding element 16, 17, 18, 19 (analogous to FIG. 1), not shown. Also in the case of the grinding element holder 11 shown in FIG. 3, abrasion occurs due to the friction between the commutator (not shown for reasons of clarity), the commutator to be arranged in the central opening 35 and the grinding element. 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 grinding element holder 11 shown in FIG. 3, together with the commutator, not shown, forms a commutation device for an electrical machine. As is apparent from Fig. 3, the direction of rotation 36 of the commutator, not shown, runs in the counterclockwise direction. The means 21 are formed in the embodiment of FIG. 3 as integral extensions of the quiver 12, 13, 14, 15, extending in the circumferential direction, starting from the associated quiver 12, 13, 14, 15 counter 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.

As is further apparent from FIG. 3, a (lower or radially inner) side 39 of the means 21 designed as extensions is arranged offset radially inwards relative to an associated, radially inner quiver opening 40, 41, 42, 43, whereby an in Circumferentially acting barrier is formed against abrasion, whereby an (excessive) impact of abrasion on the carbon brushes, not shown in Fig. 3 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 0.5mm in this embodiment is formed.

Claims

claims

1. commutation device with a rotatable commutator (2) and with at least one commutator (2) contacting grinding element (16, 17, 18, 19),

characterized,

in that means (21) are provided for removing abrasions (20) arising during the commutation.

2. Commutation device according to claim 1, characterized in that the means (21) at least one electrically non-conductive, on the commutator (2) applied spring (22,

23, 24, 25).

3. commutation device according to claim 2, characterized in that the spring (22, 23, 24, 25) as in the direction of the commutator (2) bent and / or obliquely arranged leaf spring is formed.

4. Commutation device according to one of the preceding claims, characterized in that the means (21), in particular the spring (22, 23,

24, 25) are formed from an electrically non-conductive plastic / is.

5. Commutation device according to one of the preceding claims, characterized in that in that the width of the means (21), in particular of the spring (22, 23, 24, 25), corresponds at least approximately to the axial extent of the commutator (2) or extends beyond it axially.

6. Commutation device according to one of the preceding claims, characterized in that the means (21), in particular the spring (22, 23, 24, 25), in the region of their free, the commutator (2) adjacent end (30, 31, 32nd , 33) have / have a curved or inclined contact surface.

7. Commutation device according to one of the preceding claims, characterized in that a grinding element holder (11) with a plurality of quivers (12, 13, 14, 15) for receiving a respective grinding element (16, 17, 18, 19) is provided, and that at least a quiver (12, 13, 14, 15), preferably each quiver (12, 13, 14, 15), means (21) for removing abrasion (20), in particular seen in the direction of rotation (36) of the commutator (2) in front of the quiver (12, 13, 14, 15) on the commutator (2) fitting spring (22, 23, 24, 25) are assigned / is.

8. commutation device according to claim 7, characterized in that the means (21), in particular spring (22, 23, 24, 25), integral with the grinding element holder (11) formed, or at this fixable, in particular clamped, are / is.

9. Commutation device according to one of claims 7 or 8, characterized in that the means (21), in particular the spring (22, 23, 24, 25), depending on the direction of rotation (36) of the commutator (2) in two different directional positions on the grinding element holder (11) can be fixed / is.

10. Commutation device according to one of claims 2 to 9, characterized in that the means (21) of the same material, preferably of plastic, are formed, as the associated quiver (12, 13, 14, 15) of the Schleifelementhal- ters (11 ).

11. Commutation device according to one of claims 7 to 10, characterized in that the means (21) with the associated quiver (12,

13, 14, 15) are formed as a common injection molded part.

12. Commutation device according to one of the preceding claims, characterized in that the means (21) on the commutator (2) facing side (39) in the direction of the circumferential extent of the commutator (2) are curved.

13. Commutation device according to one of the preceding claims, characterized in that the means (21), in particular at its free end, are formed like a ramp.

14. Commutation device according to one of the preceding claims, characterized in that between the means (21) and the commutator (2), in particular a minimum circumferential gap is formed.

15. Commutation device according to one of the preceding claims, characterized in that the means (21) are rigid.

16. Electrical machine, in particular electric motor or generator, with a commutation device (1) according to one of the preceding claims, the commutator

(2) is arranged rotationally fixed on an armature shaft.