Technical Field

The present invention relates to an electric motor in an electric drive motor assembly for use in a road vehicle, a phase connector for the motor extending from a motor compartment of the assembly through a housing wall into a terminal

compartment.

Background of the Invention

In a road vehicle an electric motor may be used for example as a traction motor in the rear axle of a hybrid car, where the front axle may be driven by an internal combustion engine. A rear axle electric motor assembly may contain not only the traction motor and the necessary differential mechanism but also an electric torque vectoring motor for distributing supplemental torque to the two drive half axles, to which the assembly is to be connected.

The supply of electric energy to these electric motors must be arranged in a way that is cost effective, assembly friendly, reliable, and packing effective.

The most common conventional solution is to make use of a commercially available high current connector, which may be assembly friendly and relatively reliable but not especially cost or packing effective.

Another common solution is to connect the phase cables to a terminal block (type industry motor), which may be cost effective and relatively reliable, but not especially packing effective or assembly friendly.

It is important that phase connectors for electric motors in traction systems are fluid tight or sealed, so that disconnection can be performed without oil spillage or the like, for example at service.

The automotive industry has extremely high quality demands, which among other things means that bending of the phase conductors of the motor during assembly shall be avoided in order to protect to the conductor insulation against damage.

Due to the demands on service it is highly desirable that a phase connector system for these electric motors can be disassembled and reassembled simply and securely with ordinary hand tools.

The phase connector system must have a proper insulation for high voltages.

The Invention

One or more of the above demands can according to the invention be fulfilled in that a longitudinal contact piece extends in parallel with the axis of the motor surrounded by an insulator block through an opening in the housing wall and that the contact piece is provided with contact means at its two ends for connection of an external cable and a phase conductor of the motor, respectively.

For obtaining a simple and reliable connection, cable eyes on the external cables and phase conductors are preferably connected to the contact pieces by means of screws.

For fulfilling the demand on sealing, sealing means - for example O-rings - are provided between each contact piece and its insulator block as well as between the insulator block and the housing wall.

Each contact piece is preferably arranged in a separate insulator block in a separate opening in the housing wall.

For simplifying assembly, several insulator blocks may be connected by a bridge.

For enhancing the insulator distance for its contact piece, each insulator block can be provided with ears and/or sleeves.

Brief Description of the Drawings

The invention will be described in further detail below under reference to the accompanying drawings, in which

Fig 1 is an isometric view of an electric drive motor assembly, in which the invention can be embodied,

Fig 2 is a section through the upper part of the assembly of Fig 1,

Fig 3 is an isometric view of an electric motor that can be used in the assembly of Fig 1,

Fig 4 is a section through a first embodiment of a phase connector according to the invention,

Fig 5 is an isometric view from above of a terminal box for the phase connector shown in Fig 4,

Fig 6 is an isometric view of a phase connector shown in Fig 4,

Fig 7 is an isometric view from the other end of the phase connector shown in

Fig 6,

Fig 8 is a section through a second embodiment of a phase connector according to the invention,

Fig 9 is an isometric view of a terminal box for the phase connector shown in

Fig 9,

Fig 10 is an isometric view of a phase connector shown in Fig 8, and Fig 11 is an isometric view from the other end of the phase connector shown in

Fig 10.

Detailed Description of Embodiments

Fig 1 is an isometric view of an electric drive motor assembly for a road vehicle. Especially, the assembly is an electric drive axle arrangement for a hybrid car to be used as a rear axle, where the front axle may be driven by an internal combustion engine.

In the shown case the assembly contains two electric motors, a traction motor 1 and a torque vectoring motor 2 (Fig 2), the latter distributing supplemental torque to the two drive half axles, to which the assembly is to be connected. Each motor 1, 2 is contained in a respective motor compartment in the assembly. These compartments are sealed to the outside.

As shown in Fig 3, the traction motor 1 can be provided with three radially extending phase conductors 3, preferably provided with cable eyes 3 ^' . The phase conductor arrangement can be the same for the torque vectoring motor 2.

The invention relates to an arrangement for connecting the phase conductors 3 of the motor 1 or 2 with terminal contacts in a terminal compartment, preferably integrated in a housing 4 of the assembly. (The housing 4 can consist of several members, but the singular word is used.) For the traction motor 1 there are terminal contacts 5 in a terminal compartment 6, and for the torque vectoring motor 2 there are terminal contacts 7 in a terminal compartment 8. The terminal compartments 6 and 8 are placed radially outside the motor compartments.

Reference is now made to Figs 4-7 showing the phase connectors for the traction motor 1. Each phase connector comprises as its main parts a contact piece 9 and an insulator block 10. The contact piece 9 is made of an electrically conducting material, for example copper coated with tin, whereas the insulator block 10 is made of an electrically insulating material, preferably plastic. The contact pieces 9 provide electrical contact through an opening in an internal housing wall between the phase conductors 3 of the traction motor 1 in the motor compartment inside the housing 4 and the terminal contacts 5 in the terminal compartment 6. They are substantially parallel with the axis of the motor 1 and are placed on a radius that is greater than the outer radius of the motor 1.

It is of importance that the two compartments are fluid tight or sealed in relation to each other. This tightness may be accomplished by an O-ring 9 ^' on the cylindrical contact piece 9, as shown, or embedment of the two parts in plastic and by an O-ring 10' on the cylindrical insulator block 10, as shown, or in any other appropriate way.

At mounting, the motor 1 is axially slid into the housing 1 with the phase conductors 3 extending radially out from the motor 1. The conductor eyes 3 ^' will be positioned at the contact pieces 9 and may be attached thereto by contact means, preferably simply by screws 11 in threaded axial bores in the contact pieces 9.

Correspondingly, cables 12 (Fig 1) to be sealingly carried through openings 6' in the sidewall of the terminal compartment 6 can be connected by cable eyes (not shown) to the terminal contacts 5 in the form of screws in transverse threaded bores in the contact pieces 9, so that mounting can occur vertically or from above.

Each insulator block 10 may be provided with ears or sleeves 10 ^" at the connection points in order to enhance the insulation distance in relation to the housing 4 and other parts.

After mounting, the compartment 6 may be provided with a lid 13 (Fig 1). Figs 8-11 show the corresponding phase connectors for the torque vectoring motor 2.

One cylindrical contact piece 14 for each phase conductor 3 is arranged substantially parallel with the axis of the motor 2 and is arranged in a cylindrical insulator block 15, inserted in a corresponding opening in the housing wall to the terminal compartment 8. The three insulator blocks 15 are arranged on a bridge 16 to be placed against an inner wall of the terminal compartment 8.

The fluid tightness between the respective contact pieces 14, the insulator blocks 15, and the housing 4 is provided in a way corresponding to the embodiment according to Figs 4-7.

The insulator blocks 15 are provided with ears or sleeves 15 ^" in order to enhance the insulation distance.

The phase conductor eyes 3 ^' are connected to the contact pieces 14 by screws 17, and the terminal contacts 7 in the form of screws in the contact pieces 14 attach cable eyes 18 to the contact pieces 14. Phase cables (not shown) are attached to the cable eyes 18 and extend out of the terminal box 8 into a common cable 19 (Fig 1).

The terminal box 8 can be provided with a lid 20 (Fig 1).

The shown and described design according to the invention fulfills the different demands mentioned above.

The design is assembly-friendly. The motor is simply slid axially into position in the motor compartment. There is then no need to thread or bend the phase conductors in order to obtain correct assembly positions for them. The cable eyes of the phase conductors are simply connected to the contact pieces by axial screws radially outside the motor.

The design is reliable. There are no contacts that are sensible to vibrations. The design is packing effective, as it is very compact, yet flexible.

The design is cost effective, in that it has few components with small demands on precision and expensive materials.

The design provides a tight penetration seal.

The design can easily be serviced, in that disconnection and connection of phase conductors is simple.

The design provides an excellent high voltage insulation with a very low packing volume.

Modifications are possible within the scope of the appended claims.