Electrical machine and method for manufacturing an electrical machine

Abstract

Electric machine (100), in particular a generator or a starting device such as a starter, for starting an internal combustion engine, comprising at least one carbon brush holder assembly (50) with several brush holder units (51) for receiving and / or guiding carbon brushes (52) held therein, wherein the carbon brush holder assembly (50) is composed of at least two brush holder assembly parts (50a, 50b) and the brush holder units (51) are formed of at least two cooperating brush holder parts (51a), and wherein one brush holder part (51a) is formed on each brush holder assembly part (50a, 50b), wherein the cooperating brush holder parts (51a) for axial securing of the carbon brushes (52) to be received therein are designed as shell parts and connected to each other, characterized by the fact that The shell parts, after assembly of the brush holder device parts (50a, 50b), form a brush holder unit (51) in the form of a housing with an open end for guiding the carbon brushes (52), wherein the carbon brushes (52) received in the brush holder unit (51) are limited in all other directions by the brush holder unit (51), wherein a spring storage unit is arranged at one end in the longitudinal direction of the brush holder unit (51) in order to reposition the carbon brushes at the other open end due to a preload when the carbon brushes become worn, wherein the spring storage unit and the carbon brushes (52) are inserted into the brush holder parts (51a) and mounted by joining the brush holder parts (51a).

Description

[0001] The invention relates to an electric machine, in particular a generator or a starting device such as a starter, for starting an internal combustion engine, according to the preamble of claim 1.

[0002] Furthermore, the invention relates to a method for manufacturing an electric machine, in particular a starting device, for starting an internal combustion engine, according to the preamble of claim 9. State of the art

[0003] The invention relates to a system with a starter or starter motor according to the class of independent claims.

[0004] The present invention relates to starters and starter motors for vehicles with internal combustion engines, which have an electric machine with armature and commutator, wherein the armature has an armature shaft with corresponding armature bearing.

[0005] Starters with a starter relay for vehicles with internal combustion engines are known from the prior art; these usually include a DC electric motor to drive the internal combustion engine.

[0006] In such starters or starter motors, a relay-lever system with a corresponding relay is responsible for engaging or striking the ring gear. During a strike, also referred to as a distance movement, or more precisely, an engagement movement, a relay pulls a fork lever backward. This is achieved by energizing the relay. When energized, a switching shaft interacting with a magnetic core moves axially toward or away from a contact. Such starters contain an electric motor. This electric motor has a stator, which is designed as a magnet. The electric motor also has a rotor. The rotor has an armature made of a coil with an iron core, which is rotatably mounted in a magnetic field between the pole pieces of the stator. Current is supplied to the armature via a segmented commutator and sliding contacts, known as commutator brushes or carbon brushes.When the rotor is energized, a magnetic field is also created here, which interacts with the magnetic field of the stator.

[0007] The carbon or commutator brushes are held in so-called carbon brush holders or guides. Starters typically use four or six carbon brush holders. The carbon brushes are connected to their respective positive or negative terminals by welding copper strands.

[0008] From GB 1 416 827, a brush holder for an electric machine is known, which is formed from two identical molded plastic parts. The brush holder has several mounting parts, each arranged on a divided carrier plate. The brush holder is formed by joining the carrier plates.

[0009] From DE 10 2007 059 555 A1, a brush assembly is known which consists of four stacked ring-shaped plate elements, namely two outer circuit boards, each of which is electrically connected to one or more brushes, and two intermediate guide plates made of electrically insulating material, which have a shape with projections and recesses to form radial guides for the brushes and receptacles for springs acting on the brushes. The springs are coil springs wound around a mandrel, the flat ends of which project beyond the spring are guided in a guide groove of the respective receptacle in a rotationally secure manner and can engage behind a stop. For assembly of the brush assembly, the circuit and guide plates are stacked axially and riveted, and then the brushes are inserted radially into the guides and the springs are inserted into the receptacles. Disclosure of the invention

[0010] The electrical machine and the method according to the invention, with the features of the corresponding main claim or dependent claim, have the advantage over the prior art that, in an electrical machine, in particular a generator or a starting device such as a starter, for starting an internal combustion engine, comprising at least one carbon brush holder assembly with several brush holder units for receiving and / or guiding carbon brushes held therein, it is provided that at least one of the brush holder units is designed in at least two parts with two cooperating brush holder parts, preferably also in multiple parts with several cooperating brush holder parts, which are connected to one another for axially securing the carbon brushes to be received therein. In this way, a brush holder part can be easily manufactured.By joining the brush holder components, a secure and reliable guidance of the carbon brushes held within the brush holder components is achieved. Furthermore, the installation of the carbon brushes in the brush holder components is simplified.

[0011] The electric machine preferably comprises an electric motor with a rotor and stator. In one embodiment, the electric machine is configured as a starting device, particularly as a starter. In one embodiment, the starter is equipped with a relay. In another embodiment, the starter is configured without a relay. In one embodiment, the stator has a magnet or is itself configured as a magnet. In one embodiment, the magnet is configured as a permanent magnet. In another embodiment, the magnet is configured as a temporary magnet, for example, an electromagnet excited by a coil. In particular, the electric machine is configured as a starting device for an internal combustion engine, specifically as a starter or starter motor. In one embodiment, this includes a commutator-armature unit with a commutator with commutator brushes or carbon brushes.The carbon brushes are held in a carbon brush holder assembly. The commutator-armature unit also includes an armature with a rotatable armature shaft. Current is supplied to the armature via the commutator, which drives the armature shaft.

[0012] To ensure the carbon brushes are properly arranged, they are guided and positioned within the carbon brush holder assembly, each in its own brush holder unit. The brush holder units are designed as shell-like components that, when assembled, form a housing or socket for guiding the carbon brushes along the longitudinal axis of the holder. A spring-loaded storage unit is located at one end along the longitudinal axis to automatically adjust the carbon brushes at the other end due to preload as they wear. The brush holder unit is designed as two parts, allowing for easy insertion of the spring-loaded storage unit and the carbon brushes into the parts, and assembly by joining the parts together.

[0013] The measures listed in the dependent claims enable advantageous further developments and improvements of the devices specified in the independent and subordinate claims.

[0014] In one embodiment, the brush holder components, particularly the two brush holder components, are designed to be mirror-symmetrical and / or identical. This reduces manufacturing effort. Assembly errors due to differing components are avoided. A bearing support is correspondingly reduced. The brush holder components are designed such that they form the brush holder unit simply by joining them together. The connection between the two brush holder units can be made in any desired manner. For example, a connection can be material-bonded, force-fit, and / or form-fit, such as by gluing, clamping, snapping, clipping, riveting, ultrasonic welding, screwing, and the like.

[0015] Another embodiment provides that at least one of the brush holder parts of a brush holder unit has a flange unit, thus providing an axial stop for securing the carbon brushes and orienting the brush holder part. In this way, the brush holder unit does not need to be mounted separately on a base or support body, but can be easily connected via a flange. The flange preferably extends over one end of the brush holder parts, at which the spring storage unit is located. In another embodiment, the flange is flush with the end, thus forming an enlarged base. Consequently, the carbon brushes protrude from the brush holder end at the end opposite the flange. This provides an orientation of the brush holder parts that is advantageous during assembly.

[0016] Another embodiment of the present invention provides that several brush holder parts of the same orientation are connected to one another via a common flange unit. In this way, several brush holder parts are connected via a common flange and can be joined together in one step with several brush holder parts that are also connected to one another via a common flange. The brush holder parts can be attached to the flange separately or be integrated with the flange.

[0017] Another embodiment provides that all brush holder parts oriented in the same direction and the flange units formed on these brush holder parts are integrated, in particular formed as a single piece. By manufacturing all brush holder parts oriented in the same direction and the corresponding flange parts as a single piece, a single component is realized, which can be easily connected to a single counterpart. In particular, a casting, especially an injection-molded part, is possible. The components are connected, for example, via the brush holder parts, which form a joining surface for the brush holder units.

[0018] Furthermore, in one embodiment, at least one of the flange units is connected to an electrically conductive component. Preferably, all flange units, particularly in the case of an integrated design of brush holder components and flange unit, are connected to an electrically conductive component. In one embodiment, the electrically conductive components are designed as a busbar or a brush plate. The busbar forms a positive terminal connection. The brush plate forms a negative terminal connection. In one embodiment, the carbon brush holder assembly has a plastic cover. In particular, the flange unit connected to an electrically conductive component has a plastic cover. The plastic cover is designed to reduce the risk of a short circuit between the electrically conductive components.

[0019] Another embodiment provides that the flange unit and the associated component are integrated. In this way, the brush plate and the busbar can be easily integrated into the two switch-shaped carbon brush components and assembled into a brush holder. The integrated design of the flange unit and busbar / brush plate connection of the two brush holder units can be achieved in any desired manner. For example, a connection can be material-bonded, force-fit, and / or form-fit, such as by gluing, clamping, snapping, clipping, riveting, ultrasonic welding, screwing, overmolding, and the like. Overmolding creates a plastic cover that covers the overmolded component, in particular more than 50%, preferably more than 60%, and most preferably more than 75%.In one embodiment, the brush holder assembly, in particular the brush mounting parts, has / have at least one positioning aid. This makes assembly easier.

[0020] Accordingly, in a further embodiment, the brush holder assembly is designed in two parts, with two brush holder assembly parts axially connected to each other. Each brush holder assembly part comprises several brush holder parts, which are formed in one piece via a common flange and incorporate the brush plate or the busbar. Each brush holder assembly part is thus designed as one half of the brush holder assembly, which can be joined together to form a common, two-part brush holder assembly. Preferably, all parts are mirror-symmetrical and / or identical.

[0021] In one embodiment, the flange unit can have any other shape. Accordingly, in one embodiment, the flange unit is not disc- or plate-shaped, but narrower, for example, wire- or web-shaped. The connection of two brush holder assemblies is preferably axial, so that corresponding axial end faces contact each other. The connection between the brush holder assemblies, as well as between the brush holder parts and / or the flange unit and the electrically conductive component, can be implemented in any way. For example, the connection can be made by gluing, clipping, crimping, crimping, screwing, riveting, or the like.

[0022] The inventive method with the features of the corresponding main claim or dependent claim has the advantage over the prior art that, in the manufacture of an electrical machine according to the invention, in particular a generator or a starting device for starting an internal combustion engine, comprising at least one brush holder device with several brush holder units for receiving and / or guiding carbon brushes held therein, it is provided that at least one of the brush holder units is manufactured in at least two parts with two cooperating brush holder parts, which are connected to each other for axially securing the carbon brushes to be received therein.

[0023] In a preferred embodiment, it is provided that at least one of the brush holder parts is connected to a component that conducts electrical current. Brief description of the drawings

[0024] Exemplary embodiments of the invention are shown in the drawings and explained in more detail in the following description. They show: Fig. 1 in a cross-sectional view an electric machine designed as a turning device with relay, Fig. 2. In a first view, a carbon brush holder assembly with two brush holder assembly parts with brush socket parts and a flange unit formed thereon. Fig. 3. In perspective, another embodiment of a carbon brush holder device according to... Fig. 2, Fig. 4. Perspective view showing another embodiment of the carbon brush holder device and Fig. Figure 5 shows a brush holder assembly part with integrated brush holder parts and an integrated electrically conductive component in a perspective view. Description of the exemplary embodiment

[0025] The Fig. Figure 1 shows a cross-sectional view of an electric machine 100 designed as a starting device of an internal combustion engine with relay 42, also designed as a switching or engagement relay.

[0026] The housing 10 of the electric machine 100 consists of a cylindrical housing part 11 and a cover 13, which are connected to each other by screws (not shown). The cylindrical housing part 11 is closed at the rear by the cover 13, in the central part of which an outwardly facing, closed hub is formed. A bearing is located in the hub, in which the rear end of a drive shaft or armature shaft 17 of an electric starter motor 18 is mounted, the armature of which is designated 19. Radially outside the armature 19, several magnets of the starter motor 18 are located on the wall of the housing part 11. These are designed as permanent magnets 20 in this case, but could also be of other forms, such as electrically excited magnets.

[0027] The front end of the armature shaft 17 is supported by a reduced-diameter end section 22 in a coaxial blind bore 23 (not shown) of an output shaft 24. The other end of the output shaft 24 is supported in a bearing plate 25, which closes the housing part 11, and in a hub 26 integrally formed therewith. Near its end facing the bearing plate 25, the armature shaft 17 has a toothed section 28 (sun gear) into which planet gears 29 engage. These planet gears also mesh with an external, stationary ring gear 30 of a planetary gear set 31 (= reduction gear). A planet carrier 12 drives the output shaft 24, on which a freewheel 33 is arranged. The inner ring 34 of the freewheel has a projection 35 (pinion) on which external teeth 36 are formed. The outer ring 37 of the freewheel 33 is connected to the output shaft 24 via a steep thread 38. A so-called single-track spring 39 acts upon it.By axially displacing the freewheel 33, the external teeth 36 can be engaged with a ring gear 40 of the internal combustion engine for the purpose of starting. This is achieved with the aid of the engagement relay 42, in which, when the current is switched on, a magnetic armature pivots a lever 44 via a projection 43. This lever, via a cam 45 located between disks 46, displaces the freewheel 33 to the left. The lever 44 has two arms and is pivotably mounted in a housing-fixed bearing 49 by means of a pin 48. This process is only briefly described, as it is not essential to the invention.

[0028] On the anchor shaft 17, near its rear bearing-side end, sits Fig. 1. An armature thrust washer designed as a spring steel disc, which bears against a commutator 63 on one side and against a thrust washer part which is arranged between the cover 13, serving as a commutator bearing, and the commutator 63 on the other. A carbon brush holder assembly 50 with brush socket units 51 in which carbon brushes 52 are movably arranged, with a brush plate 53 and a current guide rail (not shown here) is provided.

[0029] The brush holder units 51 are attached to the brush plate 53. These units contain the carbon brushes, carbon brushes, or commutator brushes 52, which are held under spring pressure against the commutator 63, located on the armature shaft 17. Some of the carbon brushes are negative brushes, while others are positive brushes. These are connected via leads to a cable lug, which is connected to a contact 68 of the engagement relay 42. The leads pass through a seal 70, which is located in a corresponding opening in the housing part 11. The brush plate 53 is fastened to the cover 13 with screws 62.

[0030] The two connecting wires are connected to a connecting tab, which is a metallic bent part and penetrates through the seal 70 to the outside.

[0031] The Fig. Figure 2 shows a perspective view of the carbon brush holder assembly 50 with two brush holder assembly parts 50a and 50b, each with several brush holder parts 51a of the respective brush holder unit 51 and a flange unit 54 formed thereon. The carbon brush holder assembly 50 is approximately ring-shaped with two essentially identical ring-shaped brush holder assembly parts 50a and 50b. Each brush holder assembly part 50a or 50b comprises several brush holder parts 51a, which are designed to interact with the corresponding brush holder part 51a of the corresponding brush holder assembly part 50a or 50b, respectively. Each carbon brush holder assembly 50 thus comprises a first brush holder part 51a formed in a first brush holder assembly part 50a, and a second brush holder part 51a formed on a second brush holder assembly part 50b.The brush holder parts 51a are designed such that they can be assembled to form a brush holder unit 51, thus creating a brush holder unit 51 that is approximately cuboid in shape, at least externally, with an opening for the respective carbon brush 52 facing inwards towards the carbon brush holder assembly 50. In all other directions, the carbon brush 52 is guided or limited by the brush holder unit 51. A spring-loaded storage unit is arranged on the side opposite the opening, which presses the carbon brush 52 against the commutator 63 surrounded by the carbon brush holder assembly 50. Accordingly, the carbon brush holder assembly 50 has an internal circular cylindrical receptacle for the commutator 63. The brush holder parts 51 of different brush holder assembly parts 50a, 50b are preferably identical and / or mirror-symmetrical so that they can be easily assembled.To arrange several brush holder parts 51 of a common brush holder assembly part 50a, 50b side by side, the brush holder parts 51 have a flange unit 54, or simply a flange, on one side. The flange projects laterally beyond the brush holder parts 51. This provides orientation for the brush holder parts 51. In the illustrated embodiment, a common flange unit 54 is provided for all brush holder parts 51a of a common brush holder assembly part 50a or 50b. Accordingly, the flange unit 54 is designed as an annular plate from which the brush holder parts 51 project inwards, i.e., in an assembled state, towards the respective corresponding brush holder assembly part 50a, 50b.The flange unit 54 can also be configured differently in other embodiments, for example as a bent rod, a U-shaped flange unit, a C-shaped flange unit, or a flange unit with an open contour. The brush holder parts 51 and the flange unit 54 are thus designed as an integrated, i.e., one-piece, component. Furthermore, an electrically conductive component, the brush plate 53 or a busbar 55, is integrated into each brush holder assembly part 50a, 50b. For this purpose, the brush plate 53 or the busbar 55 is received by the flange unit 54. The brush plate 53 or the busbar 55 is electrically connected to the respective carbon brushes 52 via a cable. Both brush assembly parts 50a and 50b are thus identical and can be assembled to form a carbon brush holder assembly 50.The assembly can be done in various ways, as shown in the examples in the . Fig. 3 and Fig. 4 illustrate. In Fig. 2. The brush assembly parts 50a and 50b are glued together.

[0032] The Fig. Figure 3 shows, in perspective and in a different view, another embodiment of a carbon brush holder device 50 according to Fig. 2. The same reference numerals are used for identical or similar components. For the sake of clarity, a further detailed description of components already described is omitted. The carbon brush holder assembly 50 is formed from two brush holder assembly parts 50a and 50b, which are connected to each other by clamps 56. The construction of the carbon brush holder assembly 50 otherwise corresponds essentially to the construction of the exemplary embodiment from [reference missing]. Fig. 2.

[0033] The Fig. Figure 4 shows a different perspective view of another embodiment of the carbon brush holder assembly 50. The carbon brush holder assembly 50 is also formed from two essentially identical brush holder assembly parts 50a and 50b. However, the two brush holder assembly parts 50a and 50b are not connected to each other by clamps 56, but are directly connected to each other by rivets 57. The construction of the carbon brush holder assembly 50 otherwise corresponds essentially to the construction of the embodiment shown in Figure 4. Fig. 2. In Fig. Figure 5 shows the structure of a brush assembly part 50a, 50b in more detail.

[0034] The Fig.Figure 5 shows a perspective view of a brush holder assembly 50a or 50b with integrated brush holder parts 51 and an integrated electrically conductive component 53 or 55. The illustrated brush holder assembly 50a or 50b comprises six identically oriented brush holder parts 51a, which are open in the direction of the commutator receptacle (i.e., radially inward) and in the direction of the corresponding brush holder part 51a of the associated brush holder assembly 50b or 50a, and are otherwise closed. The brush holder parts 51a are arranged approximately equally spaced circumferentially on the common flange. On the side of the flange where no brush holder parts 51a are arranged, the brush plate 53 or the busbar 55 is integrated. In the illustrated embodiment, the brush plate 53 is overmolded with the flange unit 54.For easy assembly, some brush holder parts 51a have centering or positioning aids 58 projecting towards the corresponding brush holder assembly part 50a or 50b.

Claims

[1] Electric machine (100), in particular a generator or a starting device such as a starter, for starting an internal combustion engine, comprising at least one carbon brush holder assembly (50) with several brush holder units (51) for receiving and / or guiding carbon brushes (52) held therein, wherein the carbon brush holder assembly (50) is composed of at least two brush holder assembly parts (50a, 50b) and the brush holder units (51) are formed of at least two cooperating brush holder parts (51a), and wherein one brush holder part (51a) is formed on each brush holder assembly part (50a, 50b), wherein the cooperating brush holder parts (51a) for axial securing of the carbon brushes (52) to be received therein are designed as shell parts and connected to each other, characterized by , that The shell parts, after assembly of the brush holder device parts (50a, 50b), form a brush holder unit (51) in the form of a housing with an open end for guiding the carbon brushes (52), wherein the carbon brushes (52) received in the brush holder unit (51) are limited in all other directions by the brush holder unit (51), wherein a spring storage unit is arranged at one end in the longitudinal direction of the brush holder unit (51) in order to reposition the carbon brushes at the other open end due to a preload when the carbon brushes become worn, wherein the spring storage unit and the carbon brushes (52) are inserted into the brush holder parts (51a) and mounted by joining the brush holder parts (51a). [2] Electric machine (100) according to claim 1, characterized by , that the brush holder parts (51a) are mirror-symmetrical and / or identical. [3] Electric machine (100) according to claim 1 or 2, characterized by , that at least one of the brush holder parts (51a) of a brush holder unit (51) has a flange unit (54) such that an axial stop for axial securing of the carbon brush (52) and an orientation of the brush holder part (51a) is realized. [4] Electric machine (100) according to claim 1 or 3, characterized by that several brush holder parts (51a) oriented in the same direction are connected to each other via a single, common flange unit (54). [5] Electric machine (100) according to any one of the preceding claims 1 to 4, characterized by , that all brush holder parts (51a) oriented in the same direction and the flange units (54) formed on the brush holder parts (51) oriented in the same direction are integrated, in particular formed in one piece. [6] Electric machine (100) according to any one of the preceding claims 1 to 5, characterized by, that at least one of the flange units (54) is connected to each of the electrically conductive components (53, 55). [7] Electric machine (100) according to any one of the preceding claims 1 to 6, characterized by , that the flange unit (54) and the associated component (53, 55) are designed as an integrated unit. [8] Electric machine (100) according to any one of the preceding claims 1 to 7, characterized by , that the brush holder assembly (50) is designed in two parts with two brush holder assembly parts (50a, 50b) axially connected to each other. [9] Method for manufacturing an electric machine (100), in particular a generator or a starting device, according to any one of the preceding claims 1 to 8, for starting an internal combustion engine, comprising at least one carbon brush holder device (50) with several brush holder units (51) for receiving and / or guiding carbon brushes (52) held therein, characterized by, that at least one of the brush holder units (51) is manufactured in at least two parts with two cooperating brush holder parts (51a) which are connected to each other for axial securing of the carbon brushes (52) to be accommodated therein. [10] Method according to claim 9, characterized by , that at least one of the brush holder parts (51a) is connected to a component (53, 55) that conducts electrical current.

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