DE102008000248A1 - Engine part, corrosion protection method and electric motor - Google Patents

Abstract

The invention relates to a motor part (1) for a particular of a fluid, preferably fuel, flowed through the electric motor. According to the invention, it is provided that the motor part (1) is encased with a corrosion protection film (7) at least in sections.

Description

State of the art

The The invention relates to a motor part according to the preamble of the claim 1, a method for protecting an engine part against corrosion according to the preamble of the claim 8 and an electric motor according to the preamble of claim 10.

Mechanically Commutated electric motors used in aggressive media, such as Fuel, operated, are usually partially sprayed around flow losses to minimize. In such overmolded rotors remain the radially outer surfaces of the Lamellar plates (anchor packet) before a medium attack unprotected and are therefore susceptible to corrosion. Insufficient protected against aggressive media are also common free copper surfaces on the commutator and on electrical connection wires, in particular in the area of welding, Soldering and / or hot-staking compounds the surface layers which protect by the production of the connection be broken up. Through the formed column can be aggressive Penetrate medium and lead to corrosion on (inner) metal parts. Around Such a rotor in aqueous and swelling of the plastic contributing, aggressive fluids, such as fuels with high ethanol content, operate to be able to the rotor is in practice by a complex, subsequent chemical tinning at endangered Protected against corrosion. In mass production practice proves this tinning process from many points of view as problematic and is about it also costly.

Disclosure of the invention

Technical task

Of the The invention is therefore based on the object to propose a motor part, in the case of an afterthought Tinning for corrosion protection reasons can be waived. Furthermore, the object is a corrosion protection method and to propose a correspondingly optimized electric motor.

Technical solution

Regarding the engine part is the object with the features of the claim 1, with regard to the corrosion protection method with the features of claim 8 and in terms of the electric motor with the features of claim 10. Advantageous developments of the invention are specified in the subclaims. All combinations of at least two fall within the scope of the invention from disclosed in the specification, claims and / or figures Features. To avoid repetition should be disclosed according to the method Characteristics are also considered to be in accordance with the device and can be claimed be. Likewise, devices disclosed according to the device are disclosed as being in accordance with the method apply and be claimable.

Of the The invention is based on the idea that the engine part, at least in sections, with a corrosion protection film, preferably a film-like Corrosion protective cover, to be provided, which is preferably arranged such that it the contact at least one risk of corrosion Element of the engine part with a, in particular aggressive, fluid safely prevented. By providing a corrosion protection film, especially in place of the use of a chemical tinning, The processing time (production time) can be significantly shortened. About that In addition, results from the use of a corrosion protection film for one due to the processing time reduction and the other due to the Reduced material costs a significant cost savings. Also offers the protection of at least one engine part against corrosion by the use of at least a, preferably made of plastic, corrosion protection film the possibility, the process reliability in comparison with the known tinning process to increase. In particular, when a corrosion protection film with a low Wall thickness is used Electromotive losses, as with enlarged gaps between the rotor and stator would occur safely prevented.

In a development of the invention, it is advantageously provided that the motor part to be provided with a corrosion protection foil, preferably completely encased, is a rotor of an electric motor, in particular a commutator motor. It is preferred, at least the armature package of the rotor radially outside to completely encase with a corrosion protection foil. Additionally or alternatively, it is possible to coat free metal surfaces, in particular copper surfaces of a commutator of the rotor, with a corrosion protection film. For reasons of stability, it is preferable to have a rotor with a partially or fully molded anchor packet. In addition or as an alternative to a rotor, the stator of an electric motor can also be reliably protected against corrosion by means of a corrosion protection foil which covers the latter at least in sections. It is essential, regardless of whether the motor part is a rotor or a stator, that at least one element susceptible to corrosion, preferably all elements susceptible to corrosion, of the motor part are encased by the anticorrosive film, thus ensuring direct contact with an aggressive medium, for example, egg a fuel, in particular a fuel with a high ethanol content, safe to prevent.

In Development of the invention is provided with advantage that the Corrosion protection film is arranged such that they at least an outer metal surface of the Motor part outside covered. Preferably covered the corrosion protection foil all metal surfaces of the Engine part, the otherwise immediate contact with one, in particular aggressive fluid, preferably a liquid. In other words the anticorrosion film is advantageously arranged in an area the without the corrosion protection film immediate contact to a Would have fluid.

In Development of the invention is provided with advantage that the Anti-corrosion film to prevent fluttering of the anti-corrosion film while to avoid the operation of the electric motor, fixed to the engine part is. Preferred for this purpose is an embodiment in which the corrosion protection film is formed as a shrink tube, preferably by heat shrunk onto the engine part and thus fixed.

Additionally or alternatively it is possible to form the corrosion protection film as an adhesive film. Preferably For this purpose, the anticorrosive foil has a part facing the motor part Adhesive layer on. The adhesive layer is such that their adhesive effect due to heat is activated. It is advantageous, the corrosion protection film so tight to attach to the engine part that fluid enters an area radially between the anti-corrosion foil and the engine part, in particular a metal element, safely avoided.

As mentioned in the beginning, is an embodiment preferred in which the anti-corrosion foil is formed of plastic is. Particularly suitable for the formation of corrosion protection film are polyethylene terephthalate or other chemical compounds with similar ones Properties.

Around electrical losses due to the provision of the corrosion protection foil to minimize, is provided in development of the invention advantageously that the particular flat Corrosion protection film one thickness, d. H. a material thickness of less than 150 μm having. It is particularly preferred if the corrosion protection film a thickness of less than 120 microns having. Ideally, the anticorrosive film thickness is one Range of values between about 50 μm and 100 μm selected.

The Invention leads also to a corrosion protection method for protecting a motor part from corrosion or to a manufacturing process for a corrosion-protected engine part. The core of the method is a motor part, in particular a rotor and / or Stator of an electric motor, preferably after completion the actual functional component with a corrosion protection foil (Corrosion protection case) to provide. Preferably, the anticorrosion film is at least arranged in an area of the engine part which is in operation Electric motor faces a fluid flowing through this.

In Further development of the method is provided with advantage that the Anti-corrosion film, especially under heat influence, glued to the motor part and / or shrunk. In the latter case, the corrosion protection film preferably as the engine part, at least in sections, enveloping shrink film, preferably of plastic, more preferably of polyethylene terephthalate or a similar one formed chemical compound.

Further leads the Invention on an electric motor, in particular one of a Fluid, preferably fuel, flowed through the electric motor. Especially Preferably, the electric motor is a drive motor a fuel pump for a motor vehicle. According to the invention, it is provided that at least one motor part of the electric motor, in particular the Rotor and / or the stator of the electric motor, at least in sections, preferably completely, provided with a corrosion protection film, in particular sheathed / is, wherein the anti-corrosion film, the engine part, in particular metallic Elements of the engine part, protects against corrosion by the anti-corrosion film a direct contact of the engine part or a risk of corrosion Element with an aggressive fluid, especially a liquid, preferably fuel, prevented.

Prefers has the anti-corrosion foil in a finished, in intended use located, electric motor direct fluid contact and is between a fluid-flowed gap and the one to protect Engine part, directly on the engine part, arranged.

Brief description of the drawings

Further Advantages, features and details of the invention will become apparent the following description of a preferred embodiment as well as the drawings. These show in:

1 a partially plastic-encased rotor of an electric motor for driving a fuel pump in a motor vehicle,

2 : the rotor protected against corrosion with a corrosion protection film according to 1 ,

Embodiments of the invention

In The figures are the same components and components with the same Function marked with the same reference numerals.

In 1 is designed as a rotor engine part 1 for one of an ethanol-containing fuel (eg., Ethanolanteil> 85%) flowed through electric motor shown, which serves as a drive motor of a fuel pump of a motor vehicle. The engine part 1 includes a motor shaft 2 (Armature shaft), on the rotatably an anchor packet 3 (Disc pack, anchor plate package) sits. The anchor package 3 is largely to increase the stability and for reasons of fuel guide / fuel line (flow guidance) with plastic 4 molded. In the anchor package 3 are shown not shown (overmolded) copper lines, which via a commutator 5 that is axially adjacent to the anchor package 3 is arranged to be contacted. Depending on the design of the electric motor, the rotor may also be equipped with permanent magnets to be protected from the fluid, in particular rare earth magnets.

As is apparent from the schematic representation according to 1 can be seen, protruding from steel sheets anchor packet 3 to the outer periphery of the engine part designed as a rotor 1 , This is the anchor package 3 immediately exposed to the, a circumferential gap between the rotor and a stator flowing through aggressive fuel, whereby corrosion phenomena over time are unavoidable. The axially adjacent to the anchor package 3 arranged commutator 5 has exposed copper surfaces 6 on, which are directly contacted by brushes, not shown.

To protect the engine part 1 Corrosion can damage the engine part 1 , like out 2 it can be seen, designed as a corrosion protection sheath corrosion protection film 7 be assigned. The trained as a film tube corrosion protection film 7 is this about the engine part 1 slipped over in the axial direction and in a subsequent step by external heating to the motor part 1 shrunk on the outside, leaving the anti-corrosion film 7 both the anchor package 3 as well as the copper surfaces 6 of the commutator 5 seals, ie protects against direct contact with the fuel flowing through the electric motor.

How out 2 It can be seen that not the entire engine part 1 from the anti-corrosion film 7 wrapped - which is alternatively also feasible - but the corrosion protection film 7 lies on the one hand with axial distance to the left end of the rotor outside of the plastic 4 starting from there and starting in the axial direction to the commutator 5 and from there over the in 1 externally visible copper surfaces 6 out and is set with axial distance to the right end of the rotor rotor, so that in the result direct contact between the fuel and metal areas of the engine part 1 safely avoided.

In the embodiment shown, there is the anti-corrosion foil 7 made of polyethylene terephthalate and has a thickness of less than 100 microns. Due to the small thickness of the corrosion protection film 7 Electrical power losses are avoided, or at least minimized. The engine part shown 1 comes completely without an additional tinning of the engine part 1 out.

Analogous to the casing of the motor part designed as a rotor 1 it is possible, a stator, in particular in a radially inner region facing the rotor with the aid of a corrosion protection foil 7 to protect against corrosion.

Claims (11)

Motor part for a, in particular of a fluid, preferably flowed through by fuel, electric motor, characterized in that the motor part ( 1 ) with a corrosion protection film ( 7 ), at least in sections, is covered. Engine part according to claim 1, characterized in that the engine part ( 1 ) a rotor, preferably with a plastic ( 4 ) partially or fully injected anchor package ( 3 ), or is a stator. Motor part according to one of claims 1 or 2, characterized in that the corrosion protection film ( 7 ) is arranged such that it has at least one outer metal surface, preferably all outer metal surfaces of the motor part ( 1 ) immediately covered. Motor part according to one of the preceding claims, characterized in that the corrosion protection foil ( 7 ) is designed as a shrink tube and / or shrink film. Motor part according to one of the preceding claims, characterized in that the corrosion protection foil ( 7 ) is designed as an adhesive film. Motor part according to one of the preceding claims, characterized in that the corrosion protection foil ( 7 ) Comprises polyethylene terephthalate and / or is formed therefrom. Motor part according to one of the preceding claims, characterized in that the corrosion protection foil ( 7 ) a thickness of less than 150 μm, preferably less than 120 μm, more preferably between about 50 μm and 100 μm. Method for protecting a motor part ( 1 ) against corrosion, characterized in that the engine part ( 1 ), at least in sections, with a corrosion protection film ( 7 ). A method according to claim 8, characterized in that the corrosion protection film ( 7 ), in particular under the influence of heat, on the engine part ( 1 ) and / or shrunk. Electric motor, in particular of a fluid, preferably fuel, through-flow electric motor, preferably commutator, with at least one motor part ( 1 ), characterized in that the engine part ( 1 ) is designed according to one of the preceding claims 1 to 7. Electric motor according to claim 10, characterized in that the corrosion protection film ( 7 ) is arranged such that it has direct fluid contact.