Brush holder and supporting rod device mating together

Abstract

A brush assembly (100) for a slip ring assembly of a rotating electrical machine, having at a brush holder (120) defining a cage into which a brush (103) slides; and a rod (101) extending along a second axis (D2) parallel to the first axis, for supporting the brush holder. One of the rod and the brush holder defines a recess (121), the other has a portion sized to be received into the recess the mating portion (105), the recess defined by a first wall (123, 124) disposed for abutment against the mating portion when, the mating portion received in the recess, the brush holder is driven longitudinally along the rod parallel to the second axis. The recess is defined by a second wall (122) disposed for abutment against mating portion when, the mating portion received in the recess, the brush holder is driven tangentially around the second axis.

Claims

1. A brush assembly for a slip ring assembly of a rotating electrical machine, for supporting at least one brush electrically contacting a cylindrical surface of a conductive ring of the slip ring assembly, one of the brush assembly or the conductive ring having a rotational movement around a first axis extending along a longitudinal direction, the brush assembly comprising: at least one brush holder, said brush holder defining at least one cage into which the at least one brush may be slidably received, said at least one brush holder comprising a spring element arranged and installed so as to apply a force onto the at least one brush when said at least one brush is received in the at least one cage so as to push said at least one brush against the cylindrical surface of the conductive ring, said force having a component that is parallel to a radial direction with regard to the first axis; and at least one rod device for supporting the brush holder, wherein the at least one rod device comprises an elongated member extending along a second axis that is parallel to the first axis, and comprises at least a part that is made of insulating material, wherein one of the at least one rod device and the at least one brush holder defines at least one recess, wherein an other one of the at least one rod device and the at least one brush holder comprises a mating portion that is sized to be received into the recess, wherein said recess is defined by a first wall disposed for abutment against the mating portion when, said mating portion being received in said recess, the brush holder is driven along said rod device in a longitudinal direction parallel to the second axis, wherein said recess is defined by a second wall disposed for abutment against mating portion when, said mating portion being received in said recess, the brush holder is driven in a tangential direction around the second axis.

2. The brush assembly according to claim 1, wherein the second wall is a bottom wall of the recess, and wherein the first wall upstands from said bottom wall.

3. The brush assembly according to claim 1, wherein the at least rod device and the at least one brush holder define a guide for guiding the at least one brush holder in a direction that has a radial component with regards to the first axis.

4. The brush assembly according to claim 3, wherein the guide comprises a groove.

5. The brush assembly according to claim 1, wherein the at least one brush holder defines the at least one recess and the at least one rod device comprises the mating portion.

6. The brush assembly according to claim 1, wherein the at least one rod device is arranged such that a plurality of brush holders of the at least one brush holder may be mounted onto said at least one rod device, and wherein the at least one rod device is arranged such that the one or more parts of the rod device that are made of insulating material to allow electrical insulating of the at least one brush received in one brush holder of the plurality of brush holders from the at least one brush received in another brush holder of the plurality of brush holders.

7. The brush assembly according to claim 1, wherein the part of the at least one rod device that is made of insulating material is injection molded plastic.

8. The brush assembly according to claim 1, wherein the rod device is arranged so as to support electrical connections for power and/or data distribution.

9. The brush assembly according to claim 8, wherein the electrical connections for power and/or data distribution are integrated into the at least one rod device.

10. The brush assembly according to claim 1, wherein the brush assembly further comprises at least one metal plate that defines at least one hole, wherein the at least one rod device defines a cavity adapted to receive said at least one metal plate, wherein an outer wall of the cavity defines at least one through-hole, at one or more positions corresponding to one or more positions of the at least one hole of the metal plate when the metal plate is received within said cavity.

11. The brush assembly according to claim 1, wherein the brush assembly further comprises at least one at least partially circular conductive plate that extends in a plane perpendicular to a line that has a component parallel to the first axis and the second axis.

12. The brush assembly according to claim 1, wherein the elongated member comprises a single rod element extending along the second axis.

13. The brush assembly according to claim 12, wherein the single rod element comprises the mating portion that is sized to be received into the recess.

14. The brush assembly according to claim 1, wherein the elongated member comprises a rod extending longitudinally along the second axis and onto which at least one support element is removably mounted.

15. The brush assembly according to claim 1, wherein the at least one rod device comprises, at a single end, connectors arranged for fixation onto a support, wherein the connectors are arranged so as to allow the fixation at a single location and with a single angle with regard to the support.

16. The brush assembly according to claim 1, wherein each of the at least one rod device supports a plurality of brush holders of the at least one brush holder adjacent to one another in a longitudinal direction parallel to the second axis.

17. The brush assembly according to claim 1, wherein each of the at least one rod device, on a first side, supports a first plurality of brush holders of the at least one brush holder adjacent to one another in a longitudinal direction parallel to the second axis, and wherein each of the at least one rod device, on a second side that is opposite to the first side, supports a second plurality of brush holders of the at least one brush holder adjacent to one another in a longitudinal direction parallel to the second axis.

18. The brush assembly according to claim 17, wherein the first plurality of brush holders and the second plurality of brush holders are symmetrically attached to each of the at least one rod device.

19. A slip ring assembly of a rotating electrical machine comprising at least one conductive ring having a cylindrical surface, and a brush assembly for supporting at least one brush electrically contacting the cylindrical surface of the at least one conductive ring, one of the brush assembly or the at least one conductive ring having a rotational movement around a first axis extending along a longitudinal direction, the brush assembly comprising: at least one brush holder, said brush holder defining at least one cage into which the at least one brush may be slidably received, said at least one brush holder comprising a spring element (104) arranged and installed so as to apply a force onto the at least one brush when said at least one brush is received in the at least one cage so as to push said at least one brush against the cylindrical surface of the conductive ring, said force having a component that is parallel to a radial direction with regard to the first axis; and at least one rod device for supporting the brush holder, wherein the at least one rod device comprises an elongated member extending along a second axis that is parallel to the first axis, and comprises at least a part that is made of insulating material, wherein one of the at least one rod device and the at least one brush holder defines at least one recess, wherein an other one of the at least one brush holder and the at least one rod device comprises a mating portion that is sized to be received into the recess, wherein said recess is defined by a first wall disposed for abutment against the mating portion when, said mating portion being received in said recess, the brush holder is driven along said rod device in a longitudinal direction parallel to the second axis, wherein said recess is defined by a second wall disposed for abutment against mating portion when, said mating portion being received in said recess, the brush holder is driven in a tangential direction around the second axis.

Description

(1) The invention is explained in further detail, and by way of example, with reference to the accompanying drawings wherein

(2) FIG. 1 schematically shows a system according to prior art.

(3) FIG. 2 schematically illustrates another system according to prior art.

(4) FIG. 3 illustrates an example slip ring assembly according to an embodiment of the invention.

(5) FIG. 4 illustrates an example brush assembly for the slip ring of FIG. 3.

(6) FIG. 5 illustrates an example brush holder for a brush assembly according an embodiment of the invention.

(7) FIG. 6 illustrates an example rod element for a brush assembly according to the embodiment of FIG. 4.

(8) FIG. 7 shows a portion of a brush holder close to the brush holder of FIG. 5.

(9) FIG. 8 is a detailed view of the brush holder of FIG. 7 and of a mating portion of a rod element for a brush assembly according to an embodiment of the invention.

(10) FIG. 9 is a cut-away view of a brush assembly according to an embodiment of the invention.

(11) FIG. 10 shows the brush assembly of FIG. 9.

(12) FIG. 11 shows a brush assembly according to the embodiment of FIG. 9.

(13) FIG. 12 illustrates the brush assembly according to the embodiment of FIG. 9.

(14) FIG. 13 illustrates an example slip ring assembly according to a further embodiment of the invention.

(15) FIG. 14 is a cut-away view of the slip ring assembly of FIG. 13.

(16) The following are descriptions of illustrative embodiments that when taken in conjunction with the following drawings will demonstrate the above noted features and advantages, as well as further ones. In the following description, for purposes of explanation rather than limitation, illustrative details are set forth such as architecture, interfaces, techniques, element attributes, etc. However, it will be apparent to those of ordinary skill in the art that other embodiments that depart from these details would still be understood to be within the scope of the invention. Moreover, for the purpose of clarity, detailed descriptions of well known devices, circuits, tools, techniques and methods are omitted so as not to obscure the description of the present system. It should be expressly understood that the drawings are included for illustrative purposes and do not represent the scope of the present system. In the accompanying drawings, like reference numbers in different drawings may designate similar elements.

(17) Identical references may be used on several figures to designate identical or similar elements.

(18) As illustrated on FIG. 3, a slip ring assembly 100 may comprise a plurality of conductive rings 201 and a brush assembly 102 to support and push brushes 103 against cylindrical surfaces 202 of the conductive rings 201.

(19) Further, the brush assembly 102 is arranged to transmit power and/or data that flows through the conductive rings 201 and the brushes 103.

(20) The conductive rings 201 are driven in rotation around a first axis (D1).

(21) The brush assembly 102 comprises one or several, here two, rod devices, each rod device comprising only one rod element 101.

(22) The rod elements 101 extend longitudinally along the conductive rings 201, in a direction that is parallel to the first axis (D1). Axis (D2) represents an axis along which a rod element 101 extends.

(23) The rod elements 101 are made of plastic or other insulating material.

(24) The rod elements 101 may be manufactured by injection molding.

(25) The rod elements 101 extend longitudinally over the whole length of the slip ring, or at least on 80% of this length along the first axis (D1).

(26) The brush assembly further comprises brush holders 120.

(27) As can be seen on FIG. 4, each brush holder 120 defines at least one cage, here three cages, for receiving at least one brush 103, here three brushes 103.

(28) The brushes may slide within their cages, in directions parallel or substantially parallel to the corresponding radial direction with regards to the first axis (D1). Axis (D3) represents an axis along which a corresponding brush may slide.

(29) Spring elements 104 allow pushing the brushes 103 against a corresponding cylindrical surface (referenced 202 on FIG. 3).

(30) The brush holders 120 are mounted onto a rod element 101.

(31) As shown on FIG. 5 and on FIG. 7, each brush holder 120 defines a recess 121 having a bottom wall 122 and two side walls 123, 124 upstanding with regards to this bottom wall 122.

(32) The bottom wall 122 has a planar surface, perpendicular to a direction represented by axis (D6) shown on FIG. 7. So, when the brush holder 120 is mounted on the rod element 101, most of the local tangential directions going through the bottom wall 122 have a component parallel to this axis (D6).

(33) As shown on FIG. 6 and on FIG. 8, the rod element 101 defines a plurality of mating portions, e.g. six mating portions 105. Each mating portion is to be received within a corresponding recess 121 of a brush holder.

(34) Each mating portion 105 may be an end part of a protruding portion 107 protruding radially from a main rod section 108 of the rod element 101.

(35) Each mating portion comprises an end surface 106, side walls 109, 110 opposing each other, an upper surface 111 and a lower surface 112.

(36) In this example, the bottom wall 122 of the recess is planar, and the end surface 106 of the mating portion 105 is also planar.

(37) The bottom wall 122 and the end surface 106 have similar rectangular shapes, with a small clearance, such that the mating portion could be received in the recess portion 121 while: the walls 122 and 106 being in planar contact with each other or at least very close to each other, e.g., less than 2 millimeters, the walls 110 and 124 being in contact with each other or at least very close to each other, e.g., less than 2 millimeters, and the walls 109 and 123 being in contact with each other or at least very close to each other, e.g., less than 2 millimeters.

(38) Since the walls 106 and 122 are planar, extend in the longitudinal direction and are in planar contact or very close to each other, tangential movement is prevented.

(39) The walls 123, 124 prevent longitudinal movement of the brush holder 120 with regards to the rod element 101.

(40) The brush holder may thus be pre-positioned relatively easily onto the rod element, without needing to adjust its longitudinal position not its angular position.

(41) As can be seen of FIG. 5, the walls 122, 123, 124 all extend along a same direction, illustrated by axis (D4).

(42) This direction may for example be parallel or substantially parallel to the sliding direction of the brush 103, illustrated by axis (D3).

(43) With reference to FIG. 6, the walls 109, 110 may also extend along a same direction, illustrated by axis (D5).

(44) Further, the recess 121 is opened at the upper and lower edges 125, 126 of the bottom wall 122.

(45) Therefore, the mating portion 105 may be inserted at one of these openings of the recess 121.

(46) And further, the mating portion 105 may slide with regards to the recess.

(47) As can be seen on FIG. 6 and on FIG. 8, the mating portion is defined within a thick wall 171. This thick wall defines two notches 131 at its corners. Each notch is delimited by one of the walls 109, 110 and by another, perpendicular wall 175, 176.

(48) The notches 131 extend in a direction parallel to the axis (D5).

(49) As can be seen on FIGS. 7 and 8, the side walls 123, 124 are each walls of a corresponding tongues 167, 168 extending in a direction parallel to the axis (D4), and whose walls 169, 170 are in planar contact with the walls 175, 176 of the notches 131, thus providing enhanced guiding.

(50) As illustrated on FIGS. 5 and 7, the recess 121 may be defined within a protruding part 185 that protrudes from the rest of the brush holder 120.

(51) Now referring to FIG. 4, locking means 113, 114 allows preventing this sliding movement of the mating portion 105 within the groove formed by the recess 121, thus locking the brush holder 120 with regards to the rod element 101.

(52) In this example, the locking means comprise screws 114, whose threaded rods go through corresponding holes 115 (on FIG. 6) defined within the rod element 101 and through corresponding holes 127 (on FIG. 5 and on FIG. 7) defined at the bottom wall 122 of the brush holder 120.

(53) The holes 127 at the brush holder (and/or the holes at the rod element) may be oblong so as to allow radial adjustment. In an alternative, not illustrated, embodiment, a plurality of holes having different radial positions may be provided so as to allow radial adjustment.

(54) In this example, the head of the screw 114 is at the rod element side.

(55) The rod element 101 defines a cavity 116 within the protruding portion 107. This cavity is defined by the thick wall 171 defining the mating portion 105, by two side walls 117, 118 upstanding from this thick wall 171 toward the main rod section 108, by a wall 119 of the main rod section 108 and by a lower wall 130.

(56) A metal plate 132 (on FIG. 4) may be received within this cavity 116.

(57) The lower wall 130 prevents the metal plate 132 from falling on the slip ring when the screws 114 are not set yet.

(58) The plate 132 defines holes for the screws 114 and allows protecting the rod element 101 from direct contact with the heads 113 of the screws 114. Further, due to the metal-metal contact between the screws 114 and the plate 132, the fixation is enhanced.

(59) In this example, three screws 114 are provided for each brush holder 120.

(60) In the embodiment of FIGS. 3, 4, and 6, the rod elements 101 are arranged for mechanically supporting partially circular conductive plates 141. More precisely, the rod elements 101 define upstanding walls 144, extending in planes perpendicular to the second axis (D2). These walls 144 define holes 145 for receiving a length of a bolt, thus allowing to support a plate 141.

(61) In the embodiment of FIG. 9-11, the rod element 101′ is slightly different than in the embodiment of FIG. 4, because its planar portion 133′ extends over almost all the length of the rod element 101′, e.g. over substantially 80% of its length.

(62) Fixing means, e.g. bolts 135 and nuts 156, may allow locking a connection element 134 onto the planar portion 133′.

(63) Each nut 156 may be received within a cavity 136, thus avoiding the nut to protrude from the body of the rod element.

(64) A similar cavity 136 is shown on FIG. 12.

(65) This cavity has a section adapted to mate with a corresponding nut, e.g. a hexagonal section, thus preventing rotational movement of the nut 156 within the cavity 136.

(66) The connection element 134 may be made of conductive material, e.g., metal, e.g. brass. It comprises a bottom part 158 that lies onto the planar portion 133′ of the rod element, side walls 153 forming a U with the bottom part 158 (see FIG. 10), and an upstanding portion 152 that is perpendicular to the side walls 153.

(67) The connection element 134 define holes on its side walls 153 for fixing electrical connections 151 to brush terminals, the corresponding wires being not represented in FIG. 10.

(68) The connection element 134 further comprises the upstanding main wall 152, in electrical contact with the side walls 153, and that defines a hole 154 for an electrical connection 155, thus allowing to collect the current that flows through the corresponding six brushes (or feed these six brushes).

(69) As illustrated on FIG. 11, the rod element 101′ may define holes (not shown) for fixing cable guiding elements 180, e.g. by means of screws.

(70) Wires 137 can be guided through these cable guiding elements 180.

(71) Such cabling may advantageously be done prior to the installation.

(72) The wires 137 may be connected to a sensor, e.g. a wear sensor, a temperature sensor, etc. The wires may thus be adapted for signals.

(73) Further, the brush assembly of FIG. 11 comprises a single ring support 138, onto which the rod elements 101′ are fixed at a single one 139 of their ends 139, 140.

(74) The rod element may be thicker at this single end 139 so as to withstand more efforts.

(75) The ring support 138 may be made of metal, e.g., steel.

(76) As shown of FIG. 9, fixing means comprise a cavity 142 for receiving a metal plate 181.

(77) The outer wall 182 of the cavity 142 and the metal plate may define holes for threaded holes of screws 114 to go through.

(78) A portion of the metal support may be received between the heads of the screws 141 and the outer surface of the outer wall 182. This portion of the metal support may also define holes for the screws, thus allowing locking the rod element 101′ with regards to the ring support 138 by means of metal-metal contacts.

(79) Returning back to FIG. 3, the slip ring assembly comprises three partially circular segment conductive plates 141, that are parallel to each other.

(80) These plates 141 may be made of metal.

(81) Wires 142 and electrical connections 150 allow connecting brush terminals to corresponding conductive plates 141.

(82) The partially circular segment conductive plates 141 are partly supported by an insulation support rod 143 extending perpendicularly from the plane of the plates 141, in a direction that is parallel to axis (D1).

(83) The rod 143 is also mounted on the ring support 138, at a single one of its ends.

(84) In the embodiment of FIG. 4, the rod element 101 defines three walls 144 upstanding from the planar portions 133. Each wall 144 defines a hole 145 for supporting a mechanical connection, e.g., a bolt and nut 146, for fixing a partially circular segment conductive plates 141 (see FIG. 3). The rod elements 101 thus also support the conductive plates 141.

(85) As shown on FIGS. 3 and 4, an additional brush holder 147 may be provided for earthing. This additional brush holder 147 may define a recess (not shown) and the rod element 101 may define an additional mating portion 148 dedicated to this additional brush holder 147.

(86) Now referring to the embodiment of FIG. 13 and FIG. 14, a slip ring assembly 100″ may comprise rod devices 301 for supporting brush holders 120″. In this embodiment, each rod device 301 is made of a plurality of pieces assembled together.

(87) Each rod device comprises a cylindrical steel rod 302 and a plurality of plastic support elements 303, e.g. three support elements 303 per steel rod 302.

(88) Each support element 303 is clamped onto the corresponding steel rod 302.

(89) Each support element 303 is arranged so as to mate with two brush holders 120″, the arrangement being similar as the one of FIG. 3. Each support element 303 may define a mating portion, similar to the mating portions 105, that is received into a recess of a corresponding brush holder.

(90) Each brush holder allows accommodating two brushes 103″. Each support element 303 corresponds two pairs of brushes, that is one pair of brushes on each side of the corresponding rod 302.

(91) The support element 303 is arranged for mechanically supporting partially a circular conductive plate 141″. More precisely, the support elements 303 define upstanding walls 144″, extending in planes perpendicular to longitudinal axis (D2′) of the corresponding rod 302. These walls 144″ define holes for receiving a length of a bolt 304, thus allowing supporting a plate 141.

(92) The rod elements 101, 101′ and the support elements 303 are made of composite or plastic, or in any material whose is insulating enough. The rod elements 101, 101′ and the support elements 303 are arranged so as to support brush holders 120, by means of the mating portions 105, and to (at least partly) support power/data transmission means such as the plates 141, the connection elements 134, wires 137, etc.

(93) The rod device ensures mechanical support, and electrical connection has a separate path (e.g. partially circular plates 141 that do not ensure mechanical support except possibly for wires), thus providing electrical separation by means of an appropriate creepage distance, that can be obtained depending on the material of the rod element.

(94) In a not illustrated embodiment, a rod device may comprise a metal part, e.g. a metal core or metal wires, that is at least partially covered by insulating material cast onto this metal part.