DE102019133889A1 - Electric machine with a discharge device - Google Patents

Abstract

Electric machines, in particular electric traction machines, are electrically charged during operation by induced shaft voltages. It is an object of the invention to create an electrical machine which is characterized by high operational reliability. For this purpose, an electrical machine 1 with a housing section 7, the housing section 7 delimiting a housing space 6, with a rotor 2 and with a shaft 4 , wherein the shaft 4 is electrically and geared to the rotor 2 and the shaft 4 and the rotor 2 are rotatably mounted in the housing space 6, the shaft 4 defining a main axis H, with a discharge device 15 for discharging an electrical charge and / or voltage from the rotor 2 via the shaft 4 to the housing section 7, the diverting device 15 having a first contact device 17 for electrical and mechanical connection to the shaft 4 and a second contact device 18 for the electrical and mechanical connection to the housing section 7, wherein the first and the second contact device 17, 18 are rotatable relative to each other u nd electrically contact one another in the axial direction with respect to the main axis H in a contact space 19, the discharge device 15 having a protective unit 20, the contact space 19 and the housing space 6 being sealingly separated from one another via the protective unit 20.

Description

The invention relates to an electrical machine with a discharge device with the features of the preamble of claim 1.

Electric machines, in particular electric traction machines, are electrically charged during operation by induced shaft voltages. In addition, circulating high-frequency currents can arise in motors of high performance classes. Such electrical machines generally have a rotor and a rotor shaft, which are mounted in a housing via roller bearings. The rolling bearings can be damaged due to electrical discharges or the circulating high-frequency currents. In order to avoid this, it is necessary to dissipate this electrical energy. For this purpose, for example, grounding brushes or radially acting grinding elements (carbon brushes) are known, which are used to ground the rotor shaft. Axially acting systems for shaft grounding are also known.

The pamphlet JP 2013174326 A which is arguably the closest prior art discloses an electronic anti-corrosion device having a rotating shaft driven by an electric motor; Bearings that rotatably support the rotating shaft; a discharge element electrically connected to the rotary shaft and a ground wire which grounds the discharge element in which the discharge element is electrically connected to the rotary shaft through a conductor body connected to the end face of the rotary shaft.

The invention is based on the object of creating an electrical machine which is characterized by a high level of operational reliability.

This object is achieved by an electrical machine with the features of claim 1. Preferred or advantageous embodiments of the invention emerge from the subclaims, the following description and the attached figures.

The invention relates to an electrical machine which is particularly suitable and / or designed for a vehicle. The vehicle is preferably designed as an electric vehicle, in particular as a purely electric vehicle or as a hybrid vehicle. The vehicle can be designed as a single-lane or two-lane and / or single-axle or multi-axle, in particular two-axle, vehicle. In principle, the vehicle is designed as a passenger car, a truck or a bus. Alternatively, however, the vehicle can also be designed as an electrically operated bicycle (pedelec), motorcycle (electric motorcycle), e-scooter or the like.

The electrical machine is used in particular to create and / or provide a traction torque, in particular a main traction torque, for the vehicle. For this purpose, the electrical machine can be coupled or coupled to an energy device, in particular to an energy storage device, in particular to a battery or accumulator, in order to receive energy for generating the traction torque. The electric machine is preferably designed as an electric motor.

The electrical machine has a housing section, the housing section defining and / or delimiting a housing space. In particular, the housing section is part of a housing and / or forms this. The housing is preferably constructed in several parts, the housing section forming part of the housing, for example a bearing plate. In particular, the housing section is connected to ground and / or grounded.

The electrical machine has a shaft which defines a main axis with its axis of rotation. Furthermore, the electrical machine has a stator and a rotor, which are arranged concentrically and / or coaxially with respect to one another. The shaft is connected to the rotor electrically and in terms of transmission.

In particular, the shaft is driven via and / or by the rotor. The shaft is particularly preferably designed as a rotor shaft, which is preferably connected to the rotor in a rotationally fixed, rigid and / or one-piece manner. The housing section is preferably electrically and mechanically connected to the stator.

The shaft and the rotor are rotatably mounted in the housing space. In particular, the electrical machine has at least or precisely two bearing devices which form or co-form the rotor bearing. The rotor is preferably arranged between the two bearing devices in the housing space, the shaft being rotatably supported by the bearing devices in the housing space and / or on the housing section.

The electrical machine has a diverting device which is designed and / or suitable for diverting an electrical charge and / or voltage starting from the rotor via the shaft to the housing section. In particular, the diverting device forms an electrical connection between the shaft and the housing section. In particular, there is a permanent electrical connection between the shaft and the housing section, which is both stationary and dynamic, that is, when the electrical machine is in operation.

For this purpose, the diverting device has a first contact device and a second contact device. The first contact device is used for the electrical connection to the shaft. Furthermore, the first contact device serves for the mechanical connection to the shaft, in particular so that the first contact device is fixed on the shaft. The second contact device is used for the electrical connection to the housing section. Furthermore, the second contact device serves for the mechanical connection to the housing section, in particular so that the second contact device is fixed to the housing section. The two contact devices can be rotated relative to one another, in particular when the electrical machine is in operation. When the electrical machine is in operation, the shaft rotates around the main axis, the first contact device being carried along by the rotating shaft and the second contact device remaining stationary on the housing section.

The first and the second contact device make electrical contact with one another in the axial direction with respect to the main axis in a contact space. In particular, a current path thus runs from the rotor via the shaft and the first contact device to the second contact device and the housing section. The current path formed by the diverting device has a lower resistance compared to the bearing devices, so that the discharge currents and / or voltages are diverted via the diverting device. The two contact devices are arranged coaxially to one another with respect to the main axis, the first contact device being arranged on an axial end face of the shaft and the second contact device being arranged opposite thereto on the housing section. Thus, the discharge device is implemented as a so-called "end face wave earth". Particularly preferably, the two contact devices are elastically supported on one another in the axial direction and are electrically contacted with one another at a contact point via a pressure and / or frictional contact. The contact space is delimited in the axial and / or radial direction by the first and / or the second contact device and / or the shaft and / or the housing section. The contact space is preferably defined as an annular space surrounding the main axis which at least surrounds the contact point.

In the context of the invention, it is proposed that the discharge device has a protective unit which separates the contact space and the housing space from one another in a sealing manner and / or seals them against one another. In particular, the function of the protective unit is to protect the contact space, preferably the contact point, and / or the housing space against one another and against external influences. For this purpose, the contact space is preferably designed to be closed and is separated from the housing space in the axial direction by the protective unit. In particular, the protective unit is used for dynamic and static sealing of the contact space, so that it is sealed off from the housing space when it is at a standstill and also during operation.

The advantage of the invention is, in particular, that the protective unit according to the invention ensures that the housing space is protected from the entry of foreign particles from the contact space. Damage to the electric motor can thus be reduced and safe operation of the electric machine can be ensured. Another advantage is that the protective unit protects the contact space from the entry of foreign particles from the housing space. Reliable contacting of the two contact devices can thus be ensured.

In a specific embodiment of the invention it is provided that the protective unit has an abrasion protection device. The function of the abrasion protection device is to protect the housing interior, in particular the electrical machine, against electrically conductive abrasion from one of the two contact devices. In particular, the abrasion is generated during operation of the electrical machine due to friction during a relative movement between the two contact devices. The abrasion protection device is arranged, preferably in the axial direction with respect to the main axis, between the contact space and the housing space, so that a transfer of the abrasion from the contact space into the housing space is avoided or at least reduced. The abrasion protection device is preferably designed to bridge an annular gap between the housing section and the shaft. The abrasion protection device is preferably designed to be continuous in the direction of rotation around the main axis. In particular, the abrasion protection device can be designed as a contactless rotary seal, in particular a contactless protective seal, for example a gap seal or a labyrinth seal or a groove seal.

The abrasion protection device keeps the abrasion generated during operation of the electrical machine away from the rotor and the stator, so that any short circuits generated by the abrasion in the electrical machine are avoided and the function of the electric motor is therefore not impaired.

In a further alternative or optionally supplementary embodiment, it is provided that the discharge device has a sealing device. The sealing device has the function of protecting the contact space and / or the housing space against foreign particles such as dust, moisture, splash water, oil, etc. from the environment. In particular, the second contact device is connected to the housing section via the sealing device, so that the entry of foreign particles from the environment into the housing space and / or contact space is avoided or at least reduced. The sealing device is preferably arranged in a force-locking manner between the second contact device and the housing section, so that a sealing pressure is generated. The sealing device can be designed as a static contact seal, for example a sealing ring or a flat seal.

The sealing device prevents foreign particles from entering the contact space and / or the housing space and preventing foreign particles from escaping from the housing space and / or the contact space. A particularly tight system is thus proposed, which can be used, for example, for use in demanding environments. In addition, it is ensured that, in particular when the housing space or the housing space section is designed as an oil area, an oil leakage is prevented.

In an alternative or optionally supplementary embodiment, it is provided that the protective unit has a further sealing device. The further sealing device has the function of protecting the contact space, in particular the two contact devices, against foreign particles such as dust, moisture, fats and / or oils. The contact space is preferably designed as a dry area and the adjoining housing space or an adjoining housing space section optionally as an oil area or as a dry area. In the event that the housing space or the housing space section is implemented as a dry area, the further sealing device forms a dirt-tight partition. In the event that the housing space or the housing space section is implemented as an oil area, the further sealing device forms a fluid-tight, in particular oil-tight, partition. The further sealing device is arranged, preferably in the axial direction with respect to the main axis, between the contact space and the housing space, so that the entry of foreign particles from the housing space into the contact space is avoided or at least reduced. In particular, the further sealing device is arranged in the axial direction adjacent to the abrasion protection device, preferably on the side of the housing space. The further sealing device thus serves as a type of upstream seal for the abrasion protection device. The sealing device is preferably designed as a contacting rotary seal, for example as a radial shaft sealing ring, a felt ring or a shaft lip seal.

The additional sealing device prevents foreign particles from entering the contact space and thus prevents interference or interruption of the contact point. Furthermore, the discharge device can also be used in a wet environment without impairing the discharge function.

In a further specification, it is provided that the contact space has a contact area, wherein the first and the second contact device make electrical contact with one another in the contact area. Furthermore, the contact space has a collecting area which is designed and / or suitable for collecting the abrasion of the first and / or second contact device. The collection area is used to safely collect the abrasion in order to prevent or at least reduce a distribution of the abrasion in the electrical machine. The collecting area is designed as an annular space surrounding the contact area. The collecting area preferably completely surrounds the contact area, in particular the contact point in the circumferential direction, so that the abrasion occurring during operation is collected in the collecting area and / or held back in relation to the housing space. In particular, the catchment area is delimited in the radial direction by the first and / or the second contact device and in the direction of the housing space by the protective unit, in particular the abrasion protection device.

One advantage is that the collecting area reliably collects the conductive abrasion, particularly in combination with the abrasion protection device, a particularly reliable abrasion protection against the housing space, in particular the rotor, being implemented.

In a constructive implementation, it is provided that the shaft has a bore introduced on the end face. In particular, the bore extends coaxially to the main axis. The first contact device has a first contact element guided in the bore. In particular, the contact element is movably guided in the bore in the axial direction with respect to the main axis. In addition, the first contact device has a spring element which is arranged in the bore and which is designed and / or suitable for applying a spring force to the first contact element in the direction of the second contact device. The spring member is preferably designed as a compression spring, in particular a helical spring, formed and supported on the one hand on the shaft and on the other hand on the first contact element.

Optionally, the first contact device has a guide sleeve which is arranged in the bore and which is designed and / or suitable for guiding the first contact element and / or the spring element. In particular, the guide sleeve realizes a spring seat for the spring member. The guide sleeve can be closed at the end in an axial direction so that the spring member is supported on the shaft via the sleeve. The guide sleeve is preferably received in the bore in a force-locking and / or form-locking manner, the first contact element and / or the spring element thus being electrically connected to the shaft indirectly via the sleeve.

According to this embodiment, the second contact device has a closure element connected to the housing section. In particular, the contact space is defined and / or limited by the closure element. The housing section preferably has a housing opening which is arranged coaxially and / or concentrically to the shaft and which is closed and / or covered by the closure element. In particular, the closure element is designed as a closure cover or a closure cap. The closure element is, for example, non-positively and / or positively, but preferably releasably, connected to the housing section. The second contact device has a second contact element connected to the closure element as a second discharge partner. In particular, the second contact element is firmly, preferably non-rotatably, connected to the closure element. The second contact element can be positively and / or non-positively and / or cohesively connected to the closure element. In an assembled state, the first contact element is supported in the axial direction via the second contact element on the closure element. The first and the second contact element are preferably arranged coaxially and / or concentrically to one another with respect to the main axis.

A discharge device is thus proposed which can be mounted on the end of the shaft in a particularly simple manner via the housing opening. In addition, the closure element creates a solution which enables the discharge device or individual components of the discharge device to be exchanged in a simple and cost-effective manner.

In a further embodiment it is provided that the one contact element is designed as a wear part and is made of an electrically conductive non-steel. In particular, the contact element designed as a wearing part is subject to wear due to the relative movement between the shaft and the housing section during operation of the electrical machine. In particular, the wear part is made of a metal-graphite material.

Alternatively or optionally in addition, the other contact element is designed as an integral part and made of steel or a non-ferrous metal. The component part, on the other hand, is subject to little or no wear during operation of the electrical machine. The wear part preferably has a hardness value which is lower than the hardness value of the component. In particular, the component is made of hardened steel. The term “steel” means both alloyed and unalloyed steels as materials. In particular, the term “non-ferrous metal” means all pure metals except iron and metal alloys with an iron content of less than 50%. For example, the component can be made of copper or brass.

Thus, a diverting device is proposed which ensures a reliable diverting function even at high speeds of the shaft. The targeted wear of one contact element can also prevent welds, which can occur, for example, in the case of steel-to-steel contact.

In a specific implementation it is provided that the first contact element is designed as an earthing rod guided in the bore, in particular in the guide sleeve. In particular, the grounding rod is designed as a cylindrical rod which is received in the bore or the guide sleeve in the radial direction in a form-fitting and / or precisely fitting manner. Furthermore, the second contact element is designed as a contact body held on the closure element. The contact body is preferably designed as a ball, the grounding rod being designed as the wear part and the ball as the component part. The electrical contact is established via the non-rotatably connected ball on the locking element (stator) and the grounding rod connected to the shaft (rotor).

Thus, the ball contact advantageously results in point contact at the contact point between the two contact elements, whereby the wear of the grounding rod can be reduced. In addition, in contrast to radial shaft earths, not the entire circumferential surface of the shaft is guided past the earthing rod per revolution.

In a specific implementation, it is provided that the housing space has a motor section which is designed and / or suitable for receiving the rotor and stator. Furthermore, the housing space has a gear section which is designed and / or suitable for connecting the shaft to a gear unit in terms of gear technology. The transmission device can be designed as a clutch device and / or as a shift device and / or as a transmission device. The shaft is connected to the transmission device in terms of transmission technology, in particular the shaft forms an input shaft into the transmission device. For this purpose, the shaft can, for example, have a gear wheel section or be permanently connected to a gear wheel. The gear wheel section can be formed, for example, by a toothing geometry arranged on the shaft. Alternatively, the gear wheel can be designed as a gearwheel connected to the shaft in a rotationally fixed manner. It is preferably provided that the motor section and the gear section are separated from one another, in particular dirt-tight and / or oil-tight, via a separating section in the axial direction relative to the main axis. Preferably, the motor section and the gear section together form the housing space. The shaft is preferably passed through the separating section and sealed off from the separating section via a sealing element, for example a further shaft sealing ring. Particularly preferably, the motor section is optionally implemented as the oil area or as the dry area and the gear section optionally as the oil area or as the dry area.

According to this embodiment it is provided that the diverting device is arranged on a motor side of the motor section. In particular, the discharge device is arranged at the end on the end face of the shaft, which is arranged in the motor section and / or is guided out of it. Thus, the discharge device is arranged on the side of the rotor and installed where the electrical charge and / or electrical voltage arises in the rotor, so that it can be dissipated spatially close.

Alternatively, the diverting device is arranged on a transmission side of the transmission section. In particular, the discharge device is arranged at the end on the other end face of the shaft, which is arranged in the gear section and / or is guided out of it. Thus, the diverting device is arranged on the side of the transmission device, the transmission section with the transmission device being protected by this arrangement, so that any bearings in the transmission device do not suffer any damage through the passage of current.

In a development it is provided that the electrical machine has a further discharge device. The further diverting device is constructed to be identical or identical to the diverting device already described above. One diverting device is arranged on the engine side and the other diverting device on the transmission side. A diverting device is thus arranged at each axial end of the shaft. This enables the currents / voltages to be diverted particularly reliably, so that all bearings of the electrical machine can be safely protected.

• 1 eine schematische Schnittdarstellung einer elektrischen Maschine als ein Ausführungsbeispiel der Erfindung;
• 2a, b unterschiedliche Darstellungen einer Ableitvorrichtung für die elektrische Maschine aus 1;
• 3a, b unterschiedliche Darstellungen einer weiteren Ableitvorrichtung für die elektrische Maschine aus 1.

Further features, advantages and effects of the invention emerge from the following description of preferred exemplary embodiments of the invention. It shows:

• 1 a schematic sectional view of an electrical machine as an embodiment of the invention;
• 2a, b different representations of a discharge device for the electrical machine 1 ;
• 3a, b different representations of a further discharge device for the electrical machine 1 .

1 shows an electrical machine in a schematic sectional illustration 1 as an embodiment of the invention. For example, the electric machine is designed and / or suitable for a vehicle, in particular an electric or hybrid vehicle. The electric machine 1 is designed as an electric traction machine and is used to generate and / or provide a traction torque, in particular a main traction torque, for the vehicle.

The electric machine 1 can for example be designed as a direct current, synchronous or asynchronous motor, etc.

The electric machine 1 has a rotor 2 and a stator 3 on which in relation to a major axis H are arranged coaxially and / or concentrically to one another. For example, the electrical machine 1 be electrically connected to an energy device, for example a battery or an accumulator, in order to obtain energy for generating the traction torque.

Furthermore, the electrical machine 1 a wave 4th to transfer the traction torque. The rotor 2 is with the wave 4th drive connected so that the shaft 4th over and / or through the rotor 2 is driven. The wave 4th is thus designed as a rotor shaft and is for this purpose mechanically, for example non-rotatable, and electrically with the rotor 2 connected. The wave 4th defines the main axis with its axis of rotation H .

The electric machine 1 has a housing 5 on which a housing space 6th Are defined. In the embodiment shown, the housing is 5 through the stator 3 and a first and a second housing section 7th , 8th formed, the first housing portion 7th on one axial side and the second housing section 8th on the other axial side of the stator 3 is arranged. The housing space 6th is thus in the radial direction through the stator 3 and in the axial direction through the two housing sections 7th , 8th limited.

The wave 4th and the rotor 2 are in the housing space 6th mounted rotatably via a plurality of storage devices 9. The two housing sections thereby form 7th , 8th one end shield each, with the shaft 4th about the storage facility 9a , b , c on the two housing sections 7th , 8th is supported. The storage facilities 9a , b , c are in the embodiment shown each designed as ball bearings, in particular deep groove ball bearings.

The housing space 6th is in an engine section 10 to hold the rotor 2 and into a gear section 11 for connecting the shaft to a transmission device, not shown, subdivided, the motor section 10 and the gear section 11 via a separating section 12th are spatially separated from each other and across the shaft 4th are connected to each other in terms of transmission technology.

The separation section 12th is for this purpose in the axial direction with respect to the main axis H between the motor section 10 and the gear section 11 arranged and designed as a partition. The engine section 10 is for example as a drying area and the adjoining gear section 11 formed as an oil area, wherein the separating portion 12th an oil-tight partition between the engine section 10 and the gear section 11 forms. The wave 4th is for this purpose from the motor section 10 through the separating section 12th in the gear section 11 out and over a sealing member 13th opposite the separating section 12th sealed. The sealing organ 13th is designed as a contact seal, eg a shaft sealing ring.

The wave 4th forms an input shaft to the transmission device. To this end, the electrical machine 1 a gear wheel 14th on which rotatably with the shaft 4th is connected and in the gear section 11 is arranged. The gear wheel 14th is designed as a toothed wheel and can, for example, be in engagement with a further toothed wheel, not shown, of the transmission device in order to transfer the traction torque to the transmission device.

Damaging voltages can be applied to the shaft during operation 4th and thus into the rotor 2 induced, creating a capacitive coupling between the stator 3 and the rotor 2 arises. These tensions are usually across the bearing equipment 9a of the motor section 10 or partly also by the storage devices 9b, c of the gear section 11 derived. In addition, in electrical machines 1 , especially high-performance AC motors, high-frequency currents are generated. The circulating high-frequency currents circulate due to imbalances in the magnetic flux in the stator 3 for example through the storage facilities 9a , b , c of the electric machine 1 . As a result of the discharge of the damaging voltages and the circulating high-frequency currents via the storage facilities 9a , b , c , bearing failures can occur. Sparks jump over the dielectric oil or grease film, also known as spark erosion, between the rotating parts and the bearing raceway, causing melting craters and / or a type of bearing profile (corrugation) in the bearing raceway of the bearing devices 9a , b , c caused.

To avoid the storage facilities 9a , b , c are damaged, this electrical energy must be dissipated. To this end, the electrical machine 1 a first and a second diverter 15th , 16 , as a discharge device and a further discharge device. The discharge devices 15th , 16 serve to dissipate an electrical charge and / or electrical voltage, starting from the rotor 2 over the wave 4th to the housing 5 . The case 5 is connected to ground and / or grounded so that the electrical charges and / or voltages pass through the housing 5 can be safely derived. The two discharge devices 15th , 16 are for this purpose each end on an axial end face of the shaft 4th arranged and each with the shaft 4th and with the case 5 electrically connected. Here is the first diverting device 15th on the first housing section 7th and the second diverter 16 on the second housing section 8th arranged.

The two discharge devices 15th , 16 each have a first and a second contact device 17th , 18th on which in relation to the main axis H are arranged coaxially and in the axial direction with one another in a contact space 19th electrically contact. The contact space 19th is adjacent to the housing space 6th arranged, the contact space 19th the first discharge device 15th to the motor section 10 and the contact space 19th the second diverter 16 to the gear section 11 adjoins. The first contact device 17th is electrically and mechanically, in particular non-rotatable, with the shaft 4th and the second contact device 18th is electrical and mechanical, in particular non-rotatably with the respective associated housing section 7th , 8th connected. The contact facilities 17th , 18th are also in Circumferential direction rotatable relative to one another and elastically supported on one another in the axial direction.

During the operation of the electrical machine 1 can be an abrasion at the contact point between the two contact devices 17th , 18th arise. This abrasion is conductive and can occur when entering the housing space 6th , especially the engine section 10 , a short circuit in the electrical machine 1 cause. In addition, the adjacent arrangement of the second diverting device 16 to the gear section designed as an oil area 11 , Oil in the associated contact space 19th penetrate, whereby a secure contact between the two contact devices 17th , 18th can no longer be guaranteed.

For this purpose, it is proposed that the first and the second diverting device 15th , 16 one protection unit each 20th have, which serves the contact spaces 19th opposite the housing space 6th as well as the environment. Thus becomes a diverter 15th , 16 proposed, which can be used in both dry and wet environments. This includes the structure and function of the two discharge devices 15th , 16 described in more detail in the following figures.

The 2a shows a detailed view of the motor section 10 with the installed first discharge device 15th out 1 . 2 B shows the first diverter 15th in an exploded view. As from the 2a, b can be seen from the wave 4th the end face a first axially extending bore 4a for receiving the first contact device 17th on. The first hole 4a is here as a coaxial to the main axis H arranged blind hole formed, which in an axial direction AR is open.

The first contact device 17th comprises a first contact element 21a , a spring organ 22nd as well as a guide sleeve 23 , which are assembled as a structural unit in the first hole 4a are used and have direct contact with the rotor 2 produce. The guide sleeve 23 is than one in an opposite axial direction GR formed closed cylinder sleeve, which is captive, for example via a press fit, in the first bore 4a is arranged. The first contact element 21a is designed as a cylindrical grounding rod, which is in the guide sleeve 23 is axially movably received. Here is the first contact element 21a in the opposite axial direction GR via the spring organ 22nd on the guide sleeve 23 supported and protrudes for contacting the second contact device 18th , in the axial direction AR from the guide sleeve 23 out. The spring organ 22nd is designed as a compression spring, in particular a helical compression spring, which is located in the guide sleeve 23 is added and the first contact element 21a in the axial direction AR , in particular in the direction of the second contact device 18th , acted upon by a spring force F.

The second contact device 18th has a closure element 24 as well as one with the closure element 24 connected second contact element 21b, which assembled as a structural unit in a housing opening 25a of the first housing section 7th are used and are in direct contact with the stator 3 produce. The closure element 24 is designed as a closure cap, which is used to close the housing opening 25a in the first housing section 7th for example screwed in or pressed in. The second contact element 21b is designed as a ball which is inside the contact space 19th in the opposite axial direction GR in the middle of the closure element 24 mounted, preferably non-rotatable, attached.

The contact space 19th is thereby through the closure element 24 defined and is in a contact area 19a and a catchment area 19b divided. The contact areas 19a is the area of the contact area 19th in which the two contact elements 21a , b are arranged and contact each other. The catchment area 19b is included as a contact area 19a defines the circumferential annulus, which defines the operation of the electrical machine 1 generated abrasion and against the adjacent engine section 10 holding back.

Via the two contact elements that are electrically contacted with one another 21a , b becomes a current path with the least resistance between the rotor 2 and the stator 3 via which the induced currents / voltages are safely diverted to the ground. Through the one with the housing section 7th screwable locking element 24 , is also a simple assembly of the discharge device 15th proposed, which at the same time enables cost-effective replacement of individual components in the event of service.

It is preferred that the first contact element 21a is designed as a wear part, which is made of a non-steel, for example a metal-graphite composite material. The second contact element 21b, on the other hand, is designed as a component made of steel or a steel alloy or a non-ferrous metal, such as a noble, federal or white metal or a non-ferrous metal alloy with an iron content of less than 50%. During the operation of the electrical machine 1 thus uses the first contact element 21a from, whereas the second contact element 21b remains. The spring organ takes over 22nd the function of an adjusting spring, which is the first contact element 21a with wear in the axial direction AR readjusts automatically. This allows permanent contact between the two contact elements 21a , b guaranteed. In addition, the ball contact (point contact) between the ball and the grounding rod is advantageous in that it can reduce wear on the grounding rod. In contrast to radially acting shaft earths, not the entire circumferential surface of the shaft (which depends on the diameter) is moved past the earthing rod per revolution.

To shield the conductive abrasion from the motor section 10 , instructs the protection unit 20th additionally an abrasion protection device 26th on. The abrasion protection device 26th is designed as a contactless rotary seal, for example a gap seal, which is attached to an inner circumference of the closure element 24 is arranged and opposite the shaft 4th or the end of the hole 4a protruding guide sleeve 23 forms a sealing gap. The abrasion protection device 26th thus prevents abrasion from entering the contact area 19th , especially the catchment area 19b , in the housing space 6th . The contact space 19th is thus in the radial direction as well as in the axial direction AR through the closure element 24 itself and in the opposite axial direction GR , through the abrasion protection device 26th limited.

In addition, the protection unit 20th a first sealing device 27a on which the closure element 24 compared to the first housing section 7th seals. The first sealing device 27a is designed as a static contact seal, for example as a sealing ring, which in the axial direction between the closure element 24 and the first housing section 7th , on an outer periphery of the closure element 24 is arranged. The first sealing device 27a thus prevents the entry of foreign particles, such as, for example, dirty water, dust, moisture etc., from an environment via the housing opening 25a of the first housing section 7th , in the housing space 6th .

This results in an advantageous construction of the first diverting device 15th , being the catchment area 19b together with the abrasion protection device 26th , a safe collection of the conductive abrasion ensures and thus the distribution of the abrasion in the housing space 6th is prevented. Thus, the first diverting device 15th inside the electrical machine 1 are used and is also by the first sealing device 27a Protected from environmental influences that impair efficiency.

The 3a shows a detailed view of the gear section 11 with the installed second discharge device 16 out 1 . 3b shows the second diverter 16 in an exploded view. As from the 3a, b can be seen from the wave 4th at its other axial end a second axially extending bore 4b for receiving the first contact device 17th on. The second bore 4b is one of the first bore 4a opposite blind hole formed. The second diverter 16 is identical to the first discharge device 15th formed, whereby for the sake of clarity only the essential differences compared to the first diverting device 15th is received.

The protection unit 20th the second diverter 16 a second sealing device 27b, as a further sealing device. The second sealing device 27b is designed as a contacting rotary seal, for example a radial shaft sealing ring, which on the one hand is attached to an inner circumference of the closure element 24 and on the other hand on the shaft 4th fits tightly. The second sealing device 27b thus prevents oil from entering from the gear section 11 in the contact space 19th so that the contact space 19th is designed as a further drying area. For this purpose, the second sealing device 27b is in the axial direction AR in front of the abrasion protection device 26th arranged to the in the gear section 11 any oil from the abrasion protection device 26th shield.

Thus becomes a diverter 16 proposed, which can be used in both dry and wet environments. In addition, the second discharge device 16 a safe discharge close to the gear section 11 implemented and the storage devices 9b, c of the gear section 11 protected.

List of reference symbols

1

electric machine

2

rotor

3

stator

4th

wave

4a, b

drilling

5

casing

6th

Housing space

7th

first housing section

8th

second housing section

9a, b, c

Storage facilities

10

Motor section

11

Gear section

12th

Separation section

13th

Sealing element

14th

Gear wheel

15th

first discharge device

16

second discharge device

17th

first contact device

18th

second contact device

19th

Contact space

19a

Contact area

19b

Catchment area

20th

Protection unit

21a, b

Contact elements

22nd

Spring organ

23

Guide sleeve

24

Closure element

25a, b

Housing openings

26th

Abrasion protection device

27a, b

Sealing devices

H

Main axis

AR

axial direction

GR

axial opposite direction

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• JP 2013174326 A [0003]

Claims (10)

Electrical machine (1) with a housing section (7), the housing section (7) delimiting a housing space (6), with a rotor (2) and with a shaft (4), the shaft (4) with the rotor (2 ) is electrically and geared connected and the shaft (4) and the rotor (2) are rotatably mounted in the housing space (6), the shaft (4) defining a main axis (H), with a discharge device (15) for discharge an electrical charge and / or voltage from the rotor (2) via the shaft (4) to the housing section (7), the discharge device (15) having a first contact device (17) for electrical and mechanical connection to the shaft (4) and a second contact device (18) for electrical and mechanical connection to the housing section (7), the first and the second contact device (17, 18) being rotatable relative to one another and in the axial direction in relation to the main axis (H) in a contact space (19) electrically with each other contact, characterized in that the discharge device (15) has a protective unit (20), wherein the contact space (19) and the housing space (6) are sealingly separated from one another by the protective unit (20). Electric machine (1) according to Claim 1 , characterized in that the protective unit (20) has an abrasion protection device (26), wherein the abrasion protection device (26) is arranged between the contact space (19) and the housing space (6), so that a transfer of abrasion of the first and / or the second Contact device (21a, b) from the contact space (19) into the housing space (6) is avoided or at least reduced. Electric machine (1) according to Claim 1 or 2 , characterized in that the protective unit (20) has a sealing device (27a), the sealing device (27a) being arranged between the second contact device (18) and the housing section (7, 8), so that foreign particles from an environment can enter the housing space (6) and / or contact space (19) is avoided or at least reduced. Electrical machine (1) according to one of the preceding claims, characterized in that the discharge device (16) has a further sealing device (27b), the further sealing device (27b) being arranged between the contact space (19) and the housing space (6), so that an entry of foreign particles from the housing space (6) into the contact space (19) is avoided or at least reduced. Electrical machine (1) according to one of the preceding claims, characterized in that the contact space (19) has a contact area (19a) and a collecting area (19b) for collecting abrasion of the first and / or second contact device (17, 18), wherein the first and the second contact device (17, 18) in the contact area (19a) make electrical contact with one another and wherein the collecting area (19b) is designed as an annular space surrounding the contact area (19a). Electrical machine (1) according to one of the preceding claims, characterized in that the shaft (4) has at least one bore (4a) introduced at the end and that the first contact device (17) has a first contact element (21a) guided in the bore (4a) as well as a spring member (22) arranged in the bore (4a) for applying a spring force (F) to the first contact element (21a) in the direction of the second contact device (18) and that the second contact device (18) is connected to the housing section (7 ) connected closure element (24) and a second contact element (21b) connected to the closure element (24), the first contact element (21a) being supported in the axial direction via the second contact element (21b) on the closure element (24). Electric machine (1) according to Claim 6 , characterized in that the one contact element (21a, b) is made as a wear part from an electrically conductive non-steel, in particular a metal-graphite material, and / or that the other contact element (21a, b) is made as a component Steel or a non-ferrous metal is made. Electric machine (1) according to Claim 6 or 7th , characterized in that the first contact element (21a) is designed as a grounding rod guided in the bore (4a) and / or that the second contact element (21b) is designed as a contact body held on the closure element (24). Electrical machine (1) according to one of the preceding claims, characterized in that the housing space (6) has a motor section (10) for receiving the rotor (2) and a gear section (11) for connecting the shaft (4) to a gear unit wherein the diverting device (15) is optionally arranged on a motor side of the motor section (10) or on a gear side of the gear section (11). Electric machine (1) according to Claim 9 , characterized by a further discharge device (16), the one discharge device (15) on the Motor side of the motor section (10) and the other diverting device (16) is arranged on the transmission side of the transmission section (11).

Images