Patent Application
20200313343
This application claims the benefit and priority of German Patent Application No. DE 10 2019 204 226.0 filed Mar. 27, 2019. The entire disclosure of the above application is incorporated herein by reference.
The invention relates to an electric unit, such as an electric water pump or an electric radiator fan for a motor vehicle with a plug-in connection, to a plug for a plug-in connection on an electric unit of this type, and to a method for producing a plug for a plug-in connection on an electric unit of this type.
For example, electric water pumps or electric radiator fans are understood to be electric units for a motor vehicle.
Electric water pumps are well known, for example from U.S. Pat. No. 9,360,015 B1, and are driven by an electric machine which comprises a stator and a rotor. The rotor is connected to a pump impeller for moving a fluid. The fluid enters the pump through an inlet in a volute, is brought into contact with a pump impeller, and is moved through an outlet in the volute. The rotor and the stator of the electric machine are contained in a housing which is connected to the volute. The electronics for the electric machine are contained on a printed circuit board (PCB). The printed circuit board comprises the electronic components which control the operation of the electric machine electrically. The current supply or energy is delivered via a plug which is connected to a wiring harness of the vehicle electrics. Here, the electric contact takes place via electrically conducting contact tongues of the plug which are connected electrically to the individual wires/cores of the wiring harness which are contacted electrically with corresponding electrically conductive contact receptacles of the printed circuit board. Said contact between the printed circuit board and the plug is usually configured as a plug-in connection, the plug being plugged at least partially with contact tongues which are arranged on the end side into the housing of the water pump, and a contact with the printed circuit board being established.
Electric radiator fans are likewise known in a multiplicity of embodiments, and comprise a fan impeller which is arranged axially on a drivable shaft, and a fan motor for driving, the fan impeller and the fan motor being arranged in a housing. The electronics which control the operation of the electric machine are likewise situated within the housing. The power supply or energy is also delivered in the case of the radiator fan via a plug which is connected to a wiring harness of the vehicle electrics.
Here, in the case of plug-in connections of this type, in particular in the case of the application in a motor vehicle, the production of a plug and/or a plug-in connection which is sufficiently sealed is problematic, such that firstly the contact regions which are present in the plug between contact tongues and wire ends of the cable are protected, and such that, furthermore, there is a sufficient tightness in relation to the environmental influences, in particular of moisture, between the individual wires and/or cable of the plug and the plug carrier/plug housing which receives the wires, with the result that a penetration of moisture and/or gases via the plug starting from the surroundings of the housing of the pump into the pump housing and/or starting from the surroundings of the radiator fan into the housing of the radiator fan can be prevented.
In a first aspect, the object of the invention consists in configuring an electric unit, such as a water pump or a radiator fan for a motor vehicle with a plug-in connection, in such a way that a simple and reliable electric contact is achieved which is distinguished, in particular, by the fact that the region of the connections between contact tongues and stripped ends of the individual wires of the cable of the plug is sealed, and that a sufficient tightness can be ensured, in particular, in relation to the ingress of moisture along the wires from the surroundings of the unit through the plug into the housing of the unit.
In a second aspect, the object consists in a development of a plug for a plug-in connection on an electric unit, such as a water pump or a radiator fan; the plug is to have, in particular, a strain relief means, and the plug having a seal, in particular in relation to moisture, in the region of the electric contact between the contact tongues and the wire ends of the cable, and it being possible for a sufficient tightness to be ensured with respect to, in particular, an ingress of moisture along the wires starting from the cable into the plug housing in the direction of the contact tongues.
In a third aspect of the present invention, a further object is considered to be a method for producing a plug for the plug-in connection of an electric unit. Here, in particular, an inexpensive, rapid, automatable method is to be provided.
The measures for sealing which are described in the following text provide a seal in relation to environmental influences. Within the context of the present invention, environmental influences are understood to mean atmospheric influences such as contaminants, dirt, water, oil and electrostatic discharges.
The object in the second aspect is achieved by way of the seal in the region of the electric connection between contact tongues and stripped ends of the individual wires of the cable in the plug is improved. Furthermore, a seal is achieved in the longitudinal direction of the cable or the individual wires, that is to say a seal between the cable sheath, the outer sheath of the wires and the plug housing, as a result of which a penetration of environmental influences in the region of the plug into the plug-in connection and into the housing of the unit, for example a water pump or a radiator fan, is avoided.
In addition, the plug according to the invention is configured in such a way that the individual wires of the cable are incorporated into the plug housing in a manner which is relieved from strain. This is achieved by virtue of the fact that the individual wires are plugged through corresponding bores of the plug housing, and that a non-positive/integrally joined connection is established between the individual wires and the plug housing in said leadthrough region on account of a heat process/hot pressing operation.
The potting compound consisting of a resin in the region of the connection between the individual wires and the contact tongues, which potting compound encloses the connection, produces a seal in said region and, in addition, is a barrier for penetrating atmospheric influences such as moisture along the individual wires, starting from the surroundings of the electric unit, through the plug into the housing of the electric unit.
In another embodiment which achieves the object in the first and second aspect, the stripped ends of the individual wires are connected to the contact tongues via a crimp connection. The crimp connection produces a reliable connection between the wire ends and the contact tongues. In the case of said exemplary embodiment, the seal between the individual wires and the contact tongues is produced via a thermoplastic material which encloses said connecting region and at the same time is embedded partially into a main carrier of the plug housing. As a result, a strain relief means of the individual wires is also achieved, in addition to the abovementioned sealing function which takes place via an adhesion between the plastic encapsulation of the individual wires and the thermoplastic material.
It is provided in one development of the invention that the plug of the plug-in connection has a pressure equalization duct which makes a pressure equalization possible between the housing interior of the electric unit, such as a water pump or a radiator fan, and the surroundings of the electric unit, such as a water pump or the radiator fan. By way of said advantageous refinement, the ventilation/pressure equalization can be provided in the plug in an integrated manner, with the result that a separate pressure equalization means at another location of the housing can be dispensed with.
The pressure equalization duct is advantageously provided with a membrane, preferably a Gore-Tex membrane, in the region of the inlet and/or outlet opening. As a result, a seal in relation to environmental influences such as moisture is also achieved in that region of the pressure equalization means which establishes a connection between the housing interior and the surroundings of the electric unit.
The inlet and/or outlet opening with a membrane is further advantageously arranged in that region of the plug which is in the interior of the housing after the assembly with the electric unit, such as the water pump or the radiator fan. At this location, the membrane is arranged at a protected location in the housing of the pump or the radiator fan.
In a third aspect, the present invention is achieved by way of a method for producing a plug.
The method can take place, in particular, in a rapid and automated manner. This can be achieved by virtue of the fact that, in accordance with the first exemplary embodiment of the plug, the contact tongues are fed in from a reel in the first method step. The seal as a barrier in the region of the contact between the wire ends and the contact tongues is advantageously produced by way of a potting compound in a casting process.
In accordance with one development of the method according to the invention, the membranes for sealing the pressure equalization ducts are fed in a manner which starts from a reel. As a result, the application of the membranes in the region of the inlet and outlet opening is considerably simplified, since separated membrane elements do not have to be gripped and applied.
Here, the fastening of the membranes preferably takes place via an ultrasonic welding method.
In accordance with a second design variant of the plug of the present invention, the method according to the invention is considerably simplified, in particular, by way of the production of a crimp connection between the wire ends and the contact tongues. Here, the strain relief means and the seal in the region of the wires and the plug housing are achieved rapidly and reliably by way of overmolding of a part region of the main carrier which produces a receptacle for the contact tongues, and of the wires in the region of the crimp connection with the contact tongues. Here, a thermoplastic material is preferably used as material.
Furthermore, in the case of the method with respect to the second exemplary embodiment, the second end region of the plug and the region of the barrier for sealing the contact points between the individual wires and the contact tongues are advantageously achieved by way of a thermoplastic material. As a result, the production method can be optimized, in particular, with regard to time. Curing times which are necessary in the case of the use of casting resins are dispensed with.
In the following text, the present invention will be described on the basis of exemplary embodiments, reference being made to the appended drawings, in which
In a first method step according to
In a second method step according to
Furthermore, the plug housing 34 is configured with a ventilating duct 40 which, starting from an inlet/outlet opening 42 which is arranged in the longitudinal direction in the second end region 31, runs into an inlet/outlet opening 41 which is configured angled-away by 90 degrees in the first end region 30.
After the molding of the plug housing 34, the latter is removed with embedded contact tongues 50 from the mold, and the transverse connections 55 between the contact tongues 50 are removed.
In a subsequent method step 5c, the inlet/outlet opening 41 in the first end region 30 is covered by way of an ultrasonic welding method with a membrane 44, preferably a Gore-Tex membrane.
Afterward, a strain-resistant connection is produced between the individual wires 47 in the through bores 35 by way of the application of heat and/or pressure in said region, as a result of which melting of the encapsulation 47b of the individual wires 47 and an integrally joined connection to the plastic material of the plug housing 34 are achieved (
After the production of the strain-resistant connection between the individual wires 47 and the plug housing 34 in its second end region 31, an insulation and sealing material 60, preferably a resin, is cast into the window-like recess 33 in a final method step according to
The illustration of
The sectional illustration of
In contrast to the above-described production method, in accordance with the second embodiment (shown in
In a second method step according to
After the molding method, the contact tongues 50 are held in the first end region 30 such that they are overmolded in their central region 52 in such a way that the angled-away ends 54 of the second end region 53 project freely toward the outside, starting from the plate-shaped element, and lie in an elongate recess 38 of the first end region 30. The first end regions 51 of the contact tongues 50 with crimped-on individual wires 47 protrude freely into the U-shaped recess 37, starting from the first end region 30 of the plug housing 34′.
Furthermore, the plug housing 34′ is configured with a ventilating duct 40 which, starting from an inlet/outlet opening 42 which is arranged in the longitudinal direction in a lateral limb 36, runs into an inlet/outlet opening 41 which is configured angled-away by 90 degrees in the first end region 30.
The left hand illustration of
In a subsequent method step which is shown in
As can be seen from the right hand depiction of
Before the injection molding with the thermoplastic material or following it, the membrane 44 can be welded by means of ultrasonic welding onto the inlet/outlet opening 41 in the first end region 30.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2019 204 226.0 | Mar 2019 | DE | national |
