Slip ring brush holder

Abstract

A device according to the invention comprises a brush holder for receiving a brush for transmitting energy between a rotating part and a stationary part of a slip ring with at least a first electrically conductive contact element 1 and a second electrically insulating guide element 2.

Description

[0001] The invention relates to a brush holder or casing for a slip ring brush or slip ring carbon, hereinafter referred to simply as a "brush." ​​The brush serves to transmit electrical energy and / or electrical signals between counter-rotating parts. It typically contains a block of silver graphite or copper, or similar material, which is movably secured by a brush holder or casing. At least one brush made of an electrically conductive material grinds on a sliding track made of electrically conductive material. Electrical current is transmitted through the galvanic contact between the sliding track and the brush. The entire arrangement is usually referred to as a slip ring.

[0002] DE 10 2013 204 004 A1 describes a holder for brushes in a slip ring assembly using blind rivet technology. The disadvantage here is the non-detachable connection, which makes replacing the brushes impossible in the event of a failure.

[0003] A holding and contacting device for sliding contacts made from a bent sheet metal part is described in DE 10 026 176 A1. Due to the manufacturing process, the bent sheet metal part has radii that can lead to inaccurate brush guidance. Furthermore, the distance between the electrically conductive bent part and the adjacent sliding tracks is small, which can easily lead to unwanted electrical arcing.

[0004] EP 0 662 736 A1 discloses a brush with a plurality of brush wires, in which the individual brush wires are soldered into a sleeve. Due to the large number of brush wires, manufacturing is complex, and the brush is prone to failure during use. In particular, individual brush wires can bend or break, making unintentional electrical contact with one of the adjacent sliding tracks.

[0005] A brush in which individual wires are soldered to the surface of a circuit board is disclosed in EP 1 453 155 A2. A simple parallel connection is possible here. However, the disadvantage is the high susceptibility to interference due to the mechanically stressed solder joints.

[0006] Furthermore, DE 741 640 shows a holder for the brush of a slip ring for measuring purposes, wherein the brush is held in an insulating holding element, preferably made of glass. This holding element is housed in a metallic socket. The electrical contact with the brush is established via a wire that is guided through an insulating cap at the end of the holding element opposite the sliding track. The metallic socket, which does not serve to guide the brush, extends directly onto the sliding track, making this design unsuitable for transmitting high voltages in multiple parallel sliding tracks.

[0007] Furthermore, DE 197 55 507 A1 shows a brush holder for mechanically commutating electric motors with a support plate and attached guide tubes for a brush. The guide tubes, made of brass sheet, are held by a two-part insulating housing. In this case, the insulating housing does not serve to guide the brush and increases the size of the structure, making a close arrangement of adjacent concentric sliding tracks impossible.

[0008] The invention is based on the object of designing a holder for brushes of a slip ring arrangement in such a way that good manufacturability of the brush holder is achieved and at the same time reliable electrical insulation from the adjacent sliding tracks is ensured.

[0009] This object is achieved by a device according to claim 1. Advantageous embodiments of the invention are specified in the subclaims.

[0010] The invention is described below by way of example using embodiments with reference to the drawings. Fig. 1 shows a completely assembled brush holder without a brush, Fig. 2 shows a contact element, Fig. 3 shows a further embodiment according to the invention in perspective view, Fig. 4 shows the embodiment of Figure 3 in plan view, Fig. 5 shows the embodiment of Figure 3 in side view, Fig. 6 shows a plan view of the embodiment according to the Figures 3 to 5 circuit board or carrier used; Fig. 7 shows a side view of the brush holder with the brush inserted, and Fig. 8 shows a view of the brush with an associated spring and wiring.

[0011] A brush holder according to the invention comprises a conductive contact element 1 and a non-conductive guide element 2.

[0012] The conductive contact element 1 is designed in such a way that it enables a galvanic connection with the carrier 3 of the brush holder.

[0013] The non-conductive guide element 2, along with the contact element 1, serves to hold and guide the brush. By manufacturing the guide element 2 from an electrically insulating material, the insulation distance between the electrically conductive part of the brush holder and the adjacent sliding tracks of a slip ring arrangement that are not part of the brush holder is increased, thereby achieving significantly greater clearance and insulation distances. This makes it possible to transmit higher voltages between the brush holder, brush 6, and sliding track while maintaining otherwise identical geometries.

[0014] In Fig. 1A fully assembled, multi-part brush holder according to the invention is shown, with no brush 6 yet inserted. The conductive contact element 1 is pressed into the at least partially conductive carrier 3, in this case a circuit board, thus establishing a galvanic connection. The electrically non-conductive guide element 2 is connected to the contact element 1 by means of a positive connection. This configuration allows the positive connection of the contact element 1 and the guide element 2 to simultaneously establish a positive connection with the carrier 3.

[0015] The brushes 6 are usually elongated carbon or graphite blocks with a rectangular cross-section, whereby the cross-section is selected so that it enables good electrical contact with the sliding track.

[0016] The contact element 1 and the guide element 2 extend linearly along the longitudinal direction of the brush 6, i.e. in the direction in which the brush 6 is pressed against the sliding track.

[0017] The Fig. 2 shows the contact element 1, which is designed in such a way that it is suitable for press-fitting into the carrier 3.

[0018] In the brush holder according to the invention, the electrical contact is made via the conductive contact element 1, which is preferably arranged on a side of the carrier 3 facing away from the sliding track.

[0019] The insulating guide element 2 holds and guides the brush 6 on the side of the carrier 3 facing the sliding track.

[0020] In many applications, it is necessary to arrange several sliding tracks concentrically to transmit different signals or current phases. Since the available space is limited, it is desirable to keep the distance between the concentric sliding tracks as small as possible.

[0021] Since, for reliable transmission, the brushes 6 utilize as much of the width of the sliding track as possible, there is a risk of electrical arcing between the edge of the brush holder and an adjacent sliding track. To prevent this, the invention proposes holding the brush 6 in an insulating guide element 2 on the side of the carrier 3 facing the sliding track.

[0022] On the other hand, when transmitting larger electrical power, it is no longer possible to divert the current solely via a spring 7, which braces the brush 6 in the brush holder against the sliding track. Therefore, according to the invention, the contact element 1 is designed to be conductive. This holds and guides the brush 6 on the side of the carrier 3 facing away from the sliding track. Since the brushes 6 are not subject to abrasion on this side of the carrier 3, the risk of flashover is significantly lower. Furthermore, the brush holders can be distributed along the circumference of the sliding tracks, thus preventing flashover between the contact elements 1 of adjacent sliding tracks.

[0023] As this is Figure 8As shown, a cable 9, preferably a copper cable, is pressed into the brushes 6, for example carbon brushes, a spring 7 is threaded on and then a contact plate 8 is soldered on. This contact plate 8 establishes the electrical connection between the carbon 6 and the contact element 1. When assembling such a complete brush block into the system, the brush 6 is inserted into the contact element 1 and secured with a screw cap 10, as shown in Figure 7 can be seen. During servicing, to replace a worn brush 6, the screw cap 10 is loosened, the worn brush 6 along with the spring 7, copper cable 9, and contact plate 8 are removed, and replaced with a new one. The spring 7 essentially serves to press the brush 6 onto the sliding track, while the current is conducted via the copper cable 9 and the contact element 1.

[0024] As in Figure 2As can be seen, the insulating guide element 2 is connected to the contact element 1 by means of spring clips through the carrier 3, so that they are aligned linearly in the longitudinal direction of the brush 6.

[0025] Preferably, the contact element 1 is electrically conductively connected to the carrier 3, as shown in Figure 2 indicated contact pins are visible. These can connect with corresponding conductor tracks on carrier 3.

[0026] Since, according to the invention, the inner clear cross sections of both the contact element 1 and the guide element 2 are identical, aligned with each other and adapted to the circumferential contour of the brush 6, defining a receiving space for the brush 6, the brush 6 is guided during operation by both the guide element 2 and the contact element 1. Figure 8The spring 7 shown presses the brush 6 against the sliding track. During operation, the brush 6 can move along its longitudinal direction toward the sliding track to compensate for wear on the brush 6.

[0027] Figures 3 to 6 show a further embodiment of the invention.

[0028] For better and more reliable contact with the sliding track, in this embodiment, several brushes 6—five in the example shown—are arranged so that they can be brought into contact with a sliding track. In this case, it is preferable to design the guide elements 2 as a single piece for all or several brushes 6 of a sliding track, which facilitates assembly. Furthermore, in this case, it is preferable to connect the guide element 2 to the carrier 3 via screws 4, which engage through the carrier 3 into the threaded holes of the common guide element 2.

[0029] The common guide element 2 of the multiple brushes 6 can easily be manufactured by 3D printing for smaller series, so that the brushes 6 are arranged on a circular segment according to the radius of the sliding track. For larger series, the guide element 2 can also be manufactured conventionally by die casting or injection molding.

[0030] To improve the stability of the guide element 2, webs 5 are formed between the individual guide sections of the brushes 6. This makes it possible to keep the wall thickness of the guide sections themselves low, which contributes to a compact design of the guide element 2. Furthermore, the webs 5 preferably have a recess at the end facing the sliding track so that they do not come into contact with the sliding track even in the event of unevenness or contamination, thus preventing damage.

[0031] As a preferred alternative, an opening is provided on the side of each contact element 1 facing away from the sliding track, through which the brush 6 can be replaced, as described above. This opening is closed during operation by the cap 10, which, together with the contact plate 8, serves as an abutment for the spring 7 that presses the brush 6 against the sliding track.

[0032] However, the invention is not limited to this. It is also possible to separate the contact element 1 and the guide element 2 from each other at another location and to make the brush block from Figure 8 to use.

[0033] There are various options for connecting the contact element 1 and the guide element 2: They can be connected by means of form fit, friction fit, material fit or adhesive.

[0034] Alternatively, they can be fixed by rivets, retaining rings or snap connections.

[0035] In the preferred embodiment Figures 3 to 6 The elements are connected to each other by threads.

[0036] Further preferably, the contact element 1 is electrically conductively connected to the carrier 3, either by means of press-in technology or a soldered connection.

[0037] In a further embodiment not shown, the guide elements 2 of adjacent sliding tracks can be designed in one piece, so that a large number of guide elements 2 can be securely attached to the desired positions with just a few screws.

[0038] For example, 5 brushes 6 can be provided per sliding track, and combined as an array of 25 brushes 6 to contact 5 sliding tracks for 3 phases of the current, for an earth connection, and a neutral conductor. This array can be expanded for additional sliding tracks, for example, for the transmission of control or data signals, if these are also to be transmitted via sliding contact.

[0039] In this case, care must be taken to ensure that a sufficient distance remains between the contact elements 1 of adjacent sliding tracks in order to prevent electrical arcing, for example by leaving an intermediate distance between the contact elements 1 that access a common sliding track, and by arranging the contact element 1 of the adjacent sliding track adjacent to this intermediate distance, i.e. in a gap.

Claims

1. Brush holder for receiving a brush (6) of a slip ring arrangement, wherein the brush holder has at least one guide element (2) and one contact element (1), wherein the contact element (1) is electrically conductive and the guide element (2) is electrically insulating, and wherein both elements (1, 3) are designed to hold and guide a common brush (6).

2. The brush holder according to claim 1, wherein the contact element (1) and the guide element (2) are connected to one another by means of at least one selected from the group consisting of positive locking, frictional locking, material locking and an adhesive.

3. The brush holder according to one of the preceding claims, wherein the contact element (1) and the guide element (2) are connected to one another by means of at least one selected from the group consisting of rivet, retaining ring and snap connection.

4. The brush holder according to one of the preceding claims, wherein the contact element (1) and the guide element (2) are connected to one another by means of a thread.

5. The brush holder according to one of the preceding claims, wherein the contact element (1) is electrically conductively connected to a carrier (3) by means of a connection selected from the group consisting of press-in technology and a solder connection.

6. The brush holder according to one of the preceding claims, wherein the contact element (1) and the guide element (2) have a receiving space for receiving the brush (6), which corresponds to the shape of the brush (6) and can therefore hold and guide it.

7. The brush holder according to one of the preceding claims, wherein several guide elements (2) are formed in one piece.

8. The brush holder according to claim 7, wherein the plurality of guide elements (2) are arranged along a circular segment whose radius corresponds to that of a sliding track to be contacted.

9. The brush holder according to claim 7 or 8, wherein a plurality of guide elements (2) are arranged to contact a plurality of concentrically arranged sliding tracks.

10. The brush holder according to claim 7, 8 or 9, wherein the plurality of guide elements (2) are connected to one another via webs (5).

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