Method for producing a splash-proof electrical cable connection

Abstract

Method for producing a splash-proof electrical cable connection on an electric motor (8) of a motor-pump unit (2) comprising at least the following steps: - Providing a pre-assembled, two-core cable harness (28) to which a cable lug (34, 36) is attached to each of the positive and negative conductors (30, 32); - Attaching the two cable lugs (34, 36) separately for positive and negative at two assignable connection points (24, 26) of the electric motor (8), which is designed as a DC motor; - Performing a tool-based plastic injection molding process in which a heated, insulating plastic material is injected around the connection points (24, 26) and the cable lugs (34, 35); and - Curing the plastic material, in which a protective housing (50) for the cable connection, firmly connected to the motor housing (18), is formed.

Description

[0001] The invention relates to a method for producing a splash-proof electrical cable connection on an electric motor of a motor-pump unit, a splash-proof device produced according to the method, and a motor-pump unit whose cable connection arranged on the motor housing has a splash-proof device of this type.

[0002] Motor-pump units with electric motor drives are state of the art and are used, particularly as hydraulic power units, for supplying hydraulic fluid to conveying and lifting equipment. For example, document DE 10 2008 030 715 A1 discloses such a hydraulic power unit with a hydraulic pump driven by a DC motor. In the known solution, the motor and pump, which are mounted on top of an associated fluid tank, are located within a housing, thus protecting the cable connection on the electric motor from harmful environmental influences such as splashing water. The housing, which is essentially a rectangular cuboid whose side walls are extensions of the side walls of the square-shaped tank and are therefore located at a distance from the circular cylindrical housing of the electric motor, considerably increases the external dimensions of the unit.Installation is therefore difficult in locations with limited space.

[0003] In view of this problem, the invention aims to provide splash protection for the cable connection on the electric motor of a motor-pump unit, without significantly increasing its external dimensions.

[0004] According to the invention, this problem is solved by a method comprising the process steps specified in claim 1.

[0005] Accordingly, the invention provides for a tool-based plastic injection molding process after attaching two cable lugs to the electric motor, which is designed as a DC motor. In this process, a heated insulating plastic material is injected around the connection points with the cable lugs. The curing of the plastic material forms a protective housing for the cable connection that is firmly bonded to the motor housing. This housing, formed by directly overmolding the connection points with the cable lugs and connected to the motor housing, provides splash protection without significantly increasing the external dimensions of the motor-pump unit.Without a space-enhancing hood as an outer cover, the motor-pump unit with a freestanding motor housing can be realized in a compact, splash-proof design, so that installation is easily possible even in confined spaces, such as in mobile applications.

[0006] Advantageously, the two cable lugs can be designed as components of a pre-assembled, two-core cable harness, between which an electrically conductive interference suppression capacitor is arranged in the same plane as the cable lugs. With this arrangement, the interference suppression capacitor can be injection-molded along with the component.

[0007] For the arrangement of the injected interference suppression capacitor, it is particularly advantageous to proceed in such a way that the free ends of the cable harness inserted into the two cable lugs limit an opening angle, preferably of 30°, with the cable harness in such a way that the two cable lugs are spread away from each other and limit a free opening space for receiving the interference suppression capacitor in the common installation plane.

[0008] The two connection points can penetrate the motor housing in a pin-like manner, with the two cable lugs having drilled receptacles for the connection pins to penetrate and being screwed onto these.

[0009] A heated thermoplastic polyamide, such as PA6 or PA66, in liquid state can be used as the plastic material for overmolding the cable connection, with the tool-bound injection molding process being carried out in low-pressure potting.

[0010] According to claim 6, the invention also relates to a splash guard for the electrical connection points of an electric motor of a motor-pump unit, in particular manufactured using a method according to one of claims 1 to 5, wherein the splash guard consists of a solid plastic sheath that encloses the connection points of a motor housing with cable lugs of a two-core cable harness attached thereto and is firmly connected to the motor housing.

[0011] In particularly advantageous embodiments, the splash guard is arranged in the free end area of ​​the motor housing, which can be closed by a housing cover. The plastic sheath tapers conically towards the wiring harness, partially enclosing it. When the motor cover is in place, the tapered portion of the plastic sheath maintains a predetermined distance from the housing cover. This allows, if necessary, unimpeded access to the motor housing by removing the housing cover, even with the plastic sheath remaining attached.

[0012] With a cylindrically designed motor housing and housing cover, the outer wall of the plastic jacket can, with particular advantage, follow the curvature of the aforementioned housing parts, with the other limiting walls of the plastic jacket preferably resting perpendicularly on the housing parts of the motor housing.

[0013] Furthermore, the arrangement can advantageously be such that the plastic sheath includes a suppression capacitor extending between the connection points with the cable lugs, with the plastic sheath completely enclosing all electrical components in the area of ​​the connection points, including the connection points themselves, from all sides.

[0014] According to claim 11, the invention further relates to a motor-pump unit in which a DC electric motor has a splash water protection for its cable connection arranged on its motor housing according to one of claims 6 to 10, which is manufactured in particular according to a method with the features of claims 1 to 5.

[0015] The invention is explained in detail below with reference to an embodiment shown in the drawing.

[0016] They show:

[0017] Fig. 1 a perspective oblique view of a motor-pump unit, reduced in size by a factor of approximately 2.5 compared to a practical embodiment, which is provided with a splash guard according to an embodiment of the invention;

[0018] Fig. 2 one opposite Fig. 1 Enlarged and truncated perspective oblique view of only the free end area of ​​the motor housing of the electric motor of the motor-pump unit without splash guard attached to it;

[0019] Fig. 3 one of the Fig. 2. A corresponding illustration, wherein an embodiment of the associated splash guard is shown schematically in outline lines; and

[0020] Fig. 4 one of the Fig. 3. Corresponding illustration showing the splash guard in its entirety.

[0021] The Fig. Figure 1 shows a motor-pump unit in the form of a hydraulic power unit. 2, which is essentially a circular cylindrical unit consisting of a fluid storage tank 4 , hydraulic pump 6 and direct current electric motor 8 forms. The hydraulic pump 6 is on the top of the tank 4 arranged, and the electric motor 8 is for the direct drive of the hydraulic pump 6 directly flanged to its upper surface. The hydraulic pump 6 features a side-mounted valve block 10 on, which is present in such hydraulic units 2 usual connection points 12 and internal hydraulic components, such as pressure relief valves 14 , Filter 16 and includes associated check valves. The motor housing 18 of the electric motor 8 , which one of the tank 4 possesses the corresponding outer diameter, is located at its in Fig. 1 upper end area 20 from a removable case cover 22closed. Like the Fig. 2 and Fig. Figure 3 shows that these are for forming a cable connection at the end area 20 of the engine casing 18 Connection points via contact pins 24 and 26 formed, which, carried out in isolation, the engine housing 18 to penetrate. The contact pins are spaced apart. 24 , 26 are for the case lid 22 closely spaced.

[0022] For powering the electric motor 8 is a pre-assembled, two-core cable harness 28 provided for, on whose positive and negative conductors 30 or 32 a cable lug 34 or 36 are attached. These have contact tongues at their ends. 38 and 40 These have perforated openings with which they connect to the contact pins. 24 and 26 are attached to which they are secured by means of clamping nuts.42 , 44 are determined. How Fig. 2 and Fig. 3 show the cable lugs 34 , 36 on the contact pin 24 , 26 attached in such a way that they are on the cable lugs 34 , 36 tapered end sections of the ladder 30 and 32 of the wiring harness 28 are spread apart from each other at an opening angle of approximately 30°. Between the cable lugs 34 , 36 This creates a free space in which an electrical connection is made between the contact pins. 24 , 26 switched interference suppression capacitor 46 is recorded, the one with the cable lugs 34 , 36 lies on a common level.

[0023] A protective housing serves as splash protection. 50 Made of plastic material. The manufacture of the protective housing. 50 This occurs after the wiring harness has been attached. 28and the interference suppression capacitor 46 in situ, by connecting the connection area to the adjacent end of the cable harness 28 is overmolded with the heated plastic material, while the outer shape of the protective housing is shaped. 50 determining forming tool on the outer circumference of the engine housing 18 in its end area 20 is appropriately designed. The injection molding process with an insulating thermoplastic material, such as PA6 or PA66, takes place in low-pressure potting, which avoids the risk of flash formation from material escaping between the contact surfaces of the mold and the housing circumference.

[0024] As the Fig. 1, Fig. 3 and Fig. 4 shows the finished, formed protective housing. 50 a massive plastic body, which is attached to its wiring harness 28 The reversed end area forms a segment of a ring body, which with its base 52 ( Fig. 3) on the engine housing 18 This ring segment, which is positioned perpendicular to the motor housing, 18 standing side walls 56 and an end wall 58 is limited, ends at a small axial distance from the dividing line. 54 at the transition to the housing cover 22 Just like the side walls. 56 The front wall is standing 58 of the ring segment perpendicular to the outer shell of the motor housing 18 The upper outer side 60 of the case 50 is in accordance with the outer casing of the motor housing 18 arched. Adjoining the side walls 56 The limited ring segment is followed by the plastic body of the protective housing. 50 , at a distance from the outer surface of the housing cover 22 , with a conical taper towards the wiring harness 28 , the protective housing 50 with its casing end 62, which is the exit point of the wiring harness 28 forms, tightly encloses. How Fig. 3 and Fig. 4 show that the protective housing extends 50 with its casing end 62 in the axial direction up to an exit area where the two wires of the cable harness 28 are still connected, i.e., up to a point where the cable lugs 34 , 36 the tapered ends are still joined before they spread out at an opening angle. Since this is against the front wall 58 subsequent, on the casing of the engine housing 18 adjacent ring segment in front of the dividing line 54 ends the case cover 22 , without obstruction from the protective housing 50 , removable. QUOTES INCLUDED IN THE DESCRIPTION

[0025] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0026] DE 102008030715 A1

[0002]

Claims

[1] Method for producing a splash-proof electrical cable connection on an electric motor ( 8 ) a motor-pump unit ( 2 ) with at least the following steps: – Attaching two cable lugs ( 34 , 36 ) separated into positive and negative terminals at two assignable connection points ( 24 , 26 ) of the electric motor designed as a direct current motor ( 8 ); – Performing a tool-based plastic injection molding process in which a heated insulating plastic material is injected around the connection points ( 24 , 26 ) with the cable lugs ( 34 , 35 ) is injected; and – Hardening of the plastic material, in which a component is connected to the motor housing ( 18 ) permanently attached protective housing ( 50 ) is designed for the cable connection. [2] Method according to claim 1, characterized bythat the two cable lugs ( 34 , 36 ) as components of a pre-assembled, two-core cable harness ( 28 ) are formed, between which an electrically conductive interference suppression capacitor ( 46 ) aligned in a common plane with the cable lugs ( 34 , 36 ) is arranged lying down. [3] Method according to claim 1 or 2, characterized by that the two cable lugs ( 34 , 36 ) inserted free ends ( 30 , 32 ) of the wiring harness ( 28 ) limit this opening angle, preferably of 30°, such that the two cable lugs ( 34 , 36 ) are spread apart and provide a free opening space for the interference suppression capacitor ( 46 ) limit in the common installation plane. [4] Method according to any of the preceding claims, characterized by that the two junctions ( 24 ,26 ) the engine housing ( 18 ) reach through in a pin-like manner and that the two cable lugs ( 34 , 36 ) drilled recesses for the connecting pins to pass through ( 24 , 26 ) and are screwed onto these. [5] Method according to any of the foregoing claims, characterized by that a heated thermoplastic polyamide in liquid state is used as the plastic material for overmolding the cable connection and that the tool-bound injection molding process is carried out in low-pressure potting. [6] Splash protection for the electrical connection points ( 24 , 26 ) of an electric motor ( 8 ) a motor-pump unit ( 2 ), in particular produced by a method according to one of claims 1 to 5, consisting of a solid plastic casing ( 52 ), which connects the junctions ( 24 , 26 ) of an engine housing (18 ) with attached cable lugs ( 34 , 36 ) of a two-core cable harness ( 28 ) surrounds and is firmly attached to the engine housing ( 18 ) is connected. [7] Splash water protection according to claim 6, characterized by that he is in the free terminal range ( 20 ) of the engine housing ( 18 ) is arranged, which is enclosed by a housing cover ( 22 ) is lockable, so that the plastic casing ( 50 ) in the direction of the wiring harness ( 28 ) and tapers conically, partially enveloping it, and that when the housing cover is in place ( 22 ) the tapered part of the plastic casing maintains a predetermined distance to the housing cover ( 22 ) complies. [8] Splash water protection according to claim 6 or 7, characterized by that the engine housing ( 18 ) and the housing cover ( 22 ) are cylindrical in shape and that the outer wall ( 60 ) of the plastic coating ( 50) the curvature of the aforementioned housing parts ( 20 , 22 ) follows. [9] Splash water protection according to one of claims 6 to 8, characterized by that the other boundary walls ( 56 , 58 ) of the plastic coating ( 50 ) perpendicular to the housing parts ( 20 ) of the engine housing ( 18 ) stand up. [10] Splash water protection according to one of claims 6 to 9, characterized by that the plastic coating ( 50 ) a noise suppression capacitor ( 46 ) including the one that runs between the junctions ( 24 , 26 ) with the cable lugs ( 34 , 36 ) extends, and that the plastic coating ( 50 ) all electrical components in the area of ​​the connection points ( 24 , 26 ), including the same, completely enclosing it from all sides. [11] Motor-pump unit in which a DC electric motor ( 8) for its on its engine housing ( 18 ) arranged cable connection ( 24 , 26 ) a splash guard ( 50 ) according to one of claims 6 to 10, in particular produced according to a method having the features of claims 1 to 5.

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