Description:FIELD OF THE INVENTION

[001] The present disclosure relates to powertrains in automobiles. More particularly, the present disclosure relates to an assembly comprising an electric motor and a transmission system.
BACKGROUND

[002] A motor essentially consists of two components namely, a rotor and a stator. The rotor as the name suggests is a rotating or moving part that transmits mechanical power. The stator on the other hand is a stationary or fixed part and its major functions include generating a rotating magnetic field to move the rotor.
[003] For the smooth functioning of the electric motor, a uniform air gap between the rotor and the stator is required. This is achieved by two bearings that hold the rotor in position during rotation. These bearings are held within a bearing holder that is generally incorporated as a part of the housing or in an additional bearing holder. The presence of bearings and bearing holders consumes the internal space of the motor.
[004] One such prior art discloses an implementation of a connecting structure of a gearbox and a motor, which is mainly composed of a transmission shaft rod, a bearing, a joint block, and a toothed bar. One end of the transmission shaft rod is connected with the output end of a motor, the bearing is arranged in a proper position in the gearbox, and the bearing is axially sheathed with the joint block. One end of the joint block is connected with the transmission shaft rod, the other end of the joint block is connected with the toothed bar, and the other end of a toothed shaft is engaged with a gear of the gearbox.
[005] Furthermore, apart from consumption of space, the loss factor in conventional electric motors is a matter of concern. In motors having no liquid cooling, sealed bearings are commonly used. These sealed bearings have limited capability to handle heat loss. Moreover, the bearings have significant losses, particularly at high speeds, which limit the motor’s performance at such speeds.
[006] Yet another issue that is commonly seen in electric motors is the longer shaft length of the rotor required for proper positioning of an encoder magnet. The encoder magnet and encoder Printed Circuit Board (PCB) are cost and space effective rotor position sensors that require a magnet positioned on the rotor shaft. Encoder magnets are generally positioned on the end-face of the shaft, beyond the bearing pockets or bearing holders. The static PCB which encodes the position information is then affixed facing the magnet. The encoder wiring harness is brought out of the motor housing through an opening in the housing made for the purpose. Since the encoder is an important part of high-performance motors, longer shaft lengths are needed for their functioning. The shaft length eventually dictates the motor size.
[007] Therefore, in view of the problems mentioned above, it is advantageous to provide an assembly of the motor gearbox powertrain that can overcome one or more of the problems and limitations mentioned above.
SUMMARY

[008] This summary is provided to introduce a selection of concepts, in a simplified format, that are further described in the detailed description of the invention. This summary is neither intended to identify key or essential inventive concepts of the invention nor is it intended for determining the scope of the invention.
[009] To overcome or at least mitigate one of the problems mentioned above in the state of the art, an assembly for a compact integrated motor gearbox power train is needed. It is preferable to have an assembly comprising an electric motor and a transmission system integrally encapsulated into an integrated housing as per a preferred embodiment of the present invention.
[0010] In an embodiment of the present invention, an assembly of an electric motor and a transmission system integrally encapsulated into an integrated housing is disclosed. The transmission system includes a first part of a shaft mounted between two bearings in a first portion of the integrated housing. A second part of the shaft is located in a second portion of the integrated housing and a cantilevered free end of the shaft is mounted with an encoder magnet. An encoder Printed Circuit Board (PCB) is mounted substantially coaxially with the second part of the shaft on a first side of the second portion of the integrated housing. A rotor assembly of the electric motor is affixed to the second part of the shaft and is borne by the bearings of the transmission system such that the electric motor in the second portion of the integrated housing is devoid of bearings.
[0011] To further clarify the advantages and features of the present invention, a more particular description of the invention will be rendered by reference to specific embodiments thereof, which are illustrated in the appended drawings. It is appreciated that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting of its scope. The invention will be described and explained with additional specificity and detail with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS

[0012] These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:
[0013] Figure 1 illustrates a sectional view of an assembly including an electric motor and a transmission system in an integrated housing, according to an embodiment of the present invention;
[0014] Figure 2 illustrates a shaft and its various components, according to an embodiment of the present invention;
[0015] Figure 3 illustrates the various components of a rotor assembly which includes a coupler, a balancing plate, and a rotor core, according to an embodiment of the present invention;
[0016] Figure 4 illustrates the front view and rear view of the rotor assembly, according to an embodiment of the present invention;
[0017] Figure 5 illustrates a cross sectional view of the stator and the fitment of the stator into a stator housing, according to an embodiment of the present invention;
[0018] Figure 6 illustrates a side view of the integrated assembly comprising the transmission system and the motor assembly, according to an embodiment of the present invention;
[0019] Figure 7 illustrates a sectional view of an assembly including an electric motor and a transmission system integrated in an integrated housing applicable for axial flux motors, according to an embodiment of the present invention;
[0020] Figure 8 illustrates a sectional view of an assembly including an electric motor and a transmission system integrated in an integrated housing applicable for outer rotor radial flux motors, according to an embodiment of the present invention; and
[0021] Figure 9 illustrates an implementation of the assembly of Figure 1 in an electric vehicle according to an embodiment of the present invention.
[0022] Further, skilled artisans will appreciate that elements in the drawings are illustrated for simplicity and may not have necessarily been drawn to scale. Furthermore, in terms of the construction of the device, one or more components of the device may have been represented in the drawings by conventional symbols, and the drawings may show only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the drawings with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.
DETAILED DESCRIPTION OF FIGURES

[0023] For the purpose of promoting an understanding of the principles of the present disclosure, reference will now be made to the various embodiments and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the present disclosure is thereby intended, such alterations and further modifications in the illustrated system, and such further applications of the principles of the present disclosure as illustrated therein being contemplated as would normally occur to one skilled in the art to which the present disclosure relates.
[0024] It will be understood by those skilled in the art that the foregoing general description and the following detailed description are explanatory of the present disclosure and are not intended to be restrictive thereof.
[0025] Whether or not a certain feature or element was limited to being used only once, it may still be referred to as “one or more features” or “one or more elements” or “at least one feature” or “at least one element.” Furthermore, the use of the terms “one or more” or “at least one” feature or element do not preclude there being none of that feature or element, unless otherwise specified by limiting language including, but not limited to, “there needs to be one or more” or “one or more elements is required.”
[0026] Reference is made herein to some “embodiments.” It should be understood that an embodiment is an example of a possible implementation of any features and/or elements of the present disclosure. Some embodiments have been described for the purpose of explaining one or more of the potential ways in which the specific features and/or elements of the proposed disclosure fulfil the requirements of uniqueness, utility, and non-obviousness.
[0027] Use of the phrases and/or terms including, but not limited to, “a first embodiment,” “a further embodiment,” “an alternate embodiment,” “one embodiment,” “an embodiment,” “multiple embodiments,” “some embodiments,” “other embodiments,” “further embodiment”, “furthermore embodiment”, “additional embodiment” or other variants thereof do not necessarily refer to the same embodiments. Unless otherwise specified, one or more particular features and/or elements described in connection with one or more embodiments may be found in one embodiment, or may be found in more than one embodiment, or may be found in all embodiments, or may be found in no embodiments. Although one or more features and/or elements may be described herein in the context of only a single embodiment, or in the context of more than one embodiment, or in the context of all embodiments, the features and/or elements may instead be provided separately or in any appropriate combination or not at all. Conversely, any features and/or elements described in the context of separate embodiments may alternatively be realized as existing together in the context of a single embodiment.
[0028] Any particular and all details set forth herein are used in the context of some embodiments and therefore should not necessarily be taken as limiting factors to the proposed disclosure.
[0029] The terms “comprises”, “comprising”, or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process or method that comprises a list of steps does not include only those steps but may include other steps not expressly listed or inherent to such process or method. Similarly, one or more devices or sub-systems or elements or structures or components proceeded by “comprises a” does not, without more constraints, preclude the existence of other devices or other sub-systems or other elements or other structures or other components or additional devices or additional sub-systems or additional elements or additional structures or additional components.
[0030] Embodiments of the present disclosure will be described below in detail with reference to the accompanying drawings.
[0031] For the sake of clarity, the first digit of a reference numeral of each component of the present disclosure is indicative of the Figure number, in which the corresponding component is shown. For example, reference numerals starting with digit “1” are shown at least in Figure 1. Similarly, reference numerals starting with digit “2” are shown at least in Figure 2.
[0032] It is to be noted that the term “first portion” of an integrated housing mentioned in the description below refers to the “transmission system” and the term “second portion” of the integrated housing refers to the “stator assembly” and may reflect the same meaning and may be used interchangeably in the description and figures.
[0033] Figure 1 illustrates a sectional view of an assembly (100) indicating an electric motor and a transmission system integrated in an integrated housing (120), according to an embodiment of the present invention. In particular, the assembly (100) as disclosed is an implementation of a compact integrated motor gearbox powertrain.
[0034] The assembly (100) includes an electric motor and a transmission system integrally encapsulated into integrated housing (120). Referring to Figure 1, the transmission system as shown includes a first part of a shaft (125A) mounted between two bearings (102) in a first portion (110) of the integrated housing (120). The first part of the shaft (125A) is configured to be mounted with a primary element (112) of the transmission system.
[0035] A second part of the shaft (125B) is located in a second portion (105) of the integrated housing (120) and a cantilevered free end of the shaft (125C) is mounted with an encoder magnet (104). The second part of the shaft (125B) is configured for receiving the rotor assembly (108) coaxial with a stator assembly (114) of the electric motor. The second part of the shaft (125B) comprises a key-slot for receiving a key and a circular stopper radially extending from the shaft, for preventing an axial motion of the rotor assembly (108). The shaft and its extended portion and its parts are explained in detail below with reference to Figure 2.
[0036] An encoder printed circuit board (106) is mounted substantially coaxially with the second part of the shaft (125B) on a first side (105A) of the second portion (105) of the integrated housing (120).
[0037] The wiring for the encoder printed circuit (106) is brought out of an aperture, fitted with a grommet (118) for preventing water ingress. The grommet (118) is a wire out location on the stator housing.
[0038] A rotor assembly (108) of the electric motor is affixed to the second part of the shaft (125B) and is borne by the bearings (102) of the transmission system such that the electric motor in the second portion (105) of the integrated housing (120) is devoid of bearings.
[0039] The electric motor assembly is constructed along with a transmission system. In one example, the transmission system may be a gearbox or a belt-pulley.
[0040] The electric motor includes the rotor assembly (108) mounted on the second part of the shaft (125B) through either one of a fastening mechanism such as bolting or interference fitting (press fitting). The rotor assembly (108) comprises a hollow cylindrical coupler, assembled on the shaft and maintained in a predefined position or orientation or both, by the key in the key-slot, a balancing plate coupled to a rotor core and the rotor core is interference-fit onto the coupler. The rotor assembly and its parts are explained in detail below with reference to Figure 3 and 4.
[0041] The electric motor further includes the stator assembly (114). The stator assembly (114) is mounted inside the second portion (105) of the integrated housing (120) and the separator (116). The wiring for the stator is brought out of the second portion (105) of the integrated housing (120) through an aperture, fitted with a grommet (118) for preventing water ingress. The stator assembly (114) comprises a stator core and stator windings for producing a rotating magnetic field when supplied with appropriate electrical power, wherein the stator assembly (114) is held inside the second portion (105) of the integrated housing (120) through fasteners as per one embodiment.
[0042] The stator assembly (114) along with the second part of the housing (105) is separately mounted onto the first part of the housing (110) containing the powertrain. The stator assembly (114) and its parts are explained in detail below with reference to Figure 5. The first portion (110) and second portion (105) of the integrated housing (120) are conjoined using a plurality of fastening means known in the state of the art. In the preferred embodiment, the first portion (110) and second portion (105) are conjoined using fasteners, wherein the first portion (110) and second portion (105) are merely separated with a separator (116). The separator (116) may be an integral part of the first portion (110) or the second portion (105) or both. When the two housings (105, 110) are integrated and mechanically attached to each other, the separator (116) creates a barrier between the first housing (110) and the second housing (105) through which the second part of the shaft (125A) passes and extends into the second part of the housing (105) containing the stator assembly (114) and the rotor assembly (108). The output shaft of the transmission system extends out of the portion of the integrated housing (120) and is rotatably sealed with a shaft seal for preventing water ingress.
[0043] The assembly (100) as disclosed in Figure 1 significantly reduces the axial length of the electric motor considering the use of multi-phase power cables, a magnetic encoder and associated wiring harness (119). The assembly (100) as disclosed eliminates the need for motor bearings, thereby eliminating the space and volume needed for bearing pockets or bearing holder(s) inside the electric motor. The assembly (100) is implemented in a powertrain of a vehicle (for example, electric vehicle) to achieve high speed operation, thereby eliminating the mechanical speed limits and losses due to sealed motor bearings. Each component of the assembly (100) is described in detail in the following description.
[0044] Figure 2 illustrates a shaft (200) and its various components, according to an embodiment of the present invention. The shaft (200) illustrates the second part of the shaft (125B), a cantilevered free end of the shaft (125C), a slot for encoder magnet (104), and a stopper (234). In particular, the latter part of the shaft (125B) that extends out of the transmission system (also referred to as gearbox) includes a key-slot (232) for receiving a key. The key-slot (232) and respective keys may be of various types known in the state of the art. The shaft (125B) is also equipped with a circular stopper (234) radially extending from the shaft (125B) for preventing an axial movement of the rotor assembly (108). The stopper (234) may either be an integral part of the shaft (125B) manufactured through machining and/or forging or it may be a separate component assembled on the shaft (125B) by using one or more fastening mechanisms. The cantilevered free end of the shaft (125C) is mounted with the encoder-magnet (104) that is either directly mounted on the free end of the shaft (125C) or is mounted with the encoder-magnet assembly.
[0045] Figure 3 illustrates the various components of the rotor assembly (108) which includes a coupler (300A), a balancing plate (300B), and a rotor core (300C), according to an embodiment of the present invention. The coupler (300A) includes a key slot (332), a provision (336) for shaft insertion, a provision (338) for press-fitting the rotor core and provision (340) for press-fitting the balancing plate (300B). The balancing plate (300B) illustrates the rivet positions (342) and rotor core (300C) illustrates the slots for inserting the magnets (344). The coupler (300A) is a hollow cylinder intended to be assembled on to the shaft (200) as shown in Figure 2. The coupler (300A) is assembled on to the shaft (200) through a shaft insertion (336) and is held in place by the key in the key-slot (332). The coupler (300A) may also have multiple other means to arrest its relative motion from the shaft. The coupler (300A) comprises a provision (340) for the balancing plate (300B) to be press-fit onto the coupler (300A). The coupler (300A) also comprises a provision for the rotor core (300C) to be press-fit onto it as indicated by (338).
[0046] The balancing plate (300B) is coupled to the rotor core (300C) by means of riveting at the suitable rivet positions (342) without interacting with the coupler (300A). The rotor assembly (108) is obtained by press-fitting the balancing plate (300B) and the rotor core (300C) onto the coupler (300A) at the respective positions. A second rotor assembly may preferably be obtained by press-fitting a second balancing plate coupled with a rotor core onto the other side of the coupler (300A). In the case of permanent magnet rotor core (300C), the permanent magnets are inserted into the dedicated slots (344) of the rotor assembly (108). In another embodiment, the rotor assembly (108) is balanced through vertical balancing due to the absence of a shaft. The rotor assembly (108) may also be balanced via horizontal balancing by means of a custom shaft on which the rotor assembly (108) is placed only for the purpose of balancing.
[0047] Figure 4 illustrates the front view and rear view of the rotor assembly, according to an embodiment of the present invention. Figure 4 illustrates the front view (400A) and rear view (400B) of the rotor assembly (108), according to an embodiment of the present invention. The front view (400A) of the rotor assembly (108) illustrates the shaft (125A), a stopper (434), the coupler (300A) and the rotor core (300C). The rear view (400B) of the rotor assembly (108) illustrates the balancing plate (300B), a provision for encoder magnet (104) and a bolt (446). Figure 4 indicates the rotor assembly (108) inserted into the shaft (125A). While the axial movement of the rotor assembly (108) is arrested by the stopper (434) and fastener (446), its rotation is arrested by the key (not shown in figure 4).
[0048] Figure 5 illustrates a cross sectional view (500A-B) of the stator (114) and the stator (114) fitted into a stator housing (105A), according to an embodiment of the present invention. In particular, the image (500A) indicates the stator (114) with an electrical steel or copper windings, also called as the stator windings (548). The stator (114) may or may not include magnets but is capable of producing a rotating magnetic field when supplied with appropriate electrical power. A torque is produced when the stator (114) interacts with the rotor assembly (108) that eventually drives the motor.
[0049] The stator (114) is housed inside a housing called the stator housing (105A) through fasteners as shown in (500B). The stator housing (105A) is typically made of aluminum either by shrink-fit or press-fit. The housing comprises a provision for mounting an encoder printed circuit board (PCB) or encoder assembly (106) for decoding the encoder-magnet (104) placed on the rotating shaft (125C). An off-axis encoder may also be used, and its encoding PCB or encoder assembly can accordingly be modified in the stator housing or gear housing.
[0050] The wiring for the encoder PCB or encoder assembly (106) is brought out through an aperture fitted with a grommet (118) meant for IP67 as shown in Figure 1 to prevent water ingress. The wiring harness (119) may also be brought out using a panel mount connector or other types of connectors. There may be a provision in the rear cover for assembling the PCB.
[0051] Figure 6 illustrates an arrangement (600) for assembling the transmission system with the motor assembly, according to an embodiment of the present invention. Figure 6 illustrates the first part of the shaft (125A), the transmission system (110) and the stator assembly (105) of the integrated housing (120), and the bolts (646). In particular, the assembly (600) shows the stator assembly (105) assembled with the transmission casing or transmission system (110) using multiple fastening mechanisms such as bolts (646). The transmission system (110) may have the provision for locating the stator assembly (105) by means of locating pins.
[0052] Figure 7 and Figure 8 illustrate a sectional view of an assembly (700) and (800) indicating an electric motor and a transmission system integrated in an integrated housing applicable for axial flux motors and radial flux motors respectively, according to the embodiments of the present invention. In particular, the stator and the rotor electromagnetic construction for these motors are different from the description of the motor assembly given above. This implies that only the stator core (stator winding) and the rotor core as shown in assembly (700) and assembly (800) are different from the stator and the rotor arrangement of the assembly (100) shown in Figure 1.
[0053] Figure 9 illustrates an implementation of the assembly (100) of Figure 1 in a vehicle (900), according to an embodiment of the present invention. In particular, the disclosed assembly (100) can be coupled with another transmission system to drive the front or rear wheel of the vehicle and not limited to the vehicle as shown in Figure 9.
[0054] The vehicle (900) may be an electric vehicle. The Electric Vehicle (EV) or a battery powered vehicle including, and not limited to two-wheelers such as scooters, mopeds, motorbikes/motorcycles; three-wheelers such as auto-rickshaws, four-wheelers such as cars and other Light Commercial Vehicles (LCVs) and Heavy Commercial Vehicles (HCVs) primarily work on the principle of driving an electric motor using the power from the batteries provided in the EV. Furthermore, the electric vehicle may have at least one wheel which is electrically powered to traverse such a vehicle. The term ‘wheel’ may be referred to any ground-engaging member which allows traversal of the electric vehicle over a path. The types of Evs include Battery Electric Vehicle (BEV), Hybrid Electric Vehicle (HEV) and Range Extended Electric Vehicle. However, the subsequent paragraphs pertain to the different elements of a Battery Electric Vehicle (BEV).
[0055] The primary function of the electric motor in the electric vehicle is to convert electrical energy into mechanical energy, wherein the converted mechanical energy is subsequently transferred to the transmission system of the EV to facilitate movement of the EV. Additionally, the electric motor also acts as a generator during regenerative braking (i.e., kinetic energy generated during vehicle braking/deceleration is converted into potential energy and stored in the battery of the EV). The types of motors generally employed in EVs include, but are not limited to DC series motor, Brushless DC motor (also known as BLDC motors), Permanent Magnet Synchronous Motor (PMSM), Three Phase AC Induction Motors and Switched Reluctance Motors (SRM).
[0056] The transmission system of the EV facilitates the transfer of the generated mechanical energy by the electric motor to the wheels of the EV. Generally, the transmission systems used in Evs include single speed transmission system and multi-speed (i.e., two-speed) transmission system, wherein the single speed transmission system comprises a single gear pair whereby the EV is maintained at a constant speed. However, the multi-speed/two-speed transmission system comprises a compound planetary gear system with a double pinion planetary gear set and a single pinion planetary gear set thereby resulting in two different gear ratios which facilitates higher torque and vehicle speed.
[0057] Furthermore, embodiments of the disclosed devices and systems may be readily implemented, fully or partially, in software using, for example, object or object-oriented software development environments that provide portable source code that can be used on a variety of computer platforms. Alternatively, embodiments of the disclosed methods, processes, modules, devices, systems, and computer program product can be implemented partially or fully in hardware using, for example, standard logic circuits or a very-large-scale integration (VLSI) design. Other hardware or software can be used to implement embodiments depending on the speed and/or efficiency requirements of the systems, the particular function, and/or particular software or hardware system, microprocessor, or microcomputer being utilized.
[0058] In this application, unless specifically stated otherwise, the use of the integrated includes the plural and the use of “or” means “and/or.” Furthermore, use of the terms “including” or “having” is not limiting. Any range described herein will be understood to include the endpoints and all values between the endpoints. Features of the disclosed embodiments may be combined, rearranged, omitted, etc., within the scope of the invention to produce additional embodiments. Furthermore, certain features may sometimes be used to advantage without a corresponding use of other features.
List of reference numerals:
Components Reference numerals
Assembly 100
Bearings
102
Encoder Magnet 104
Second Portion of integrated housing 105
First side of Second portion 105A
Encoder Printed Circuit Board 106
Rotor Assembly 108
First portion of integrated housing 110
Primary Element 112
Stator Assembly 114
Separator 116
Grommet 118
Wiring harness 119
Integrated Housing 120
First part of Shaft 125A
Second part of Shaft 125B
Cantilevered free end of the Shaft 125C
Shaft 200
Key-slot 232
Stopper 234
Coupler 300A
Key-slot 332
Shaft insertion 336
Provision for rotor core to be press-fit 338
Provision for balancing plate to be press-fit 340
Balancing plate 300B
Rivet position 342
Rotor core 300C
Slots for magnet 344
Stopper 434
Fastening Mechanism (Bolts) 446
Cross-sectional view of Stator 500A
Winding 548
Cross-sectional view of Stator Housing 500B
Cross-sectional view of the Assembly 600
Bolts 646
Sectional view of Assembly for Axial Flux Motors 700
Sectional view of Assembly for Radial Flux Motors 800
Implementation of the Assembly in an Electric Vehicle 900

, Claims:1. An integrated assembly of an electric motor and a transmission system, the integrated assembly (100) comprising:
the electric motor and the transmission system integrally encapsulated into an integrated housing (120);
the transmission system comprising a first part (125A), a second part (125B) and a cantilevered free end (125C), wherein an encoder magnet (104) is mounted at the cantilevered free end (125C) of the shaft (125);
an encoder printed circuit board (106) mounted on a predefined surface of the integrated housing (120), wherein the encoder printed circuit board (106) is mounted substantially coaxially with the second part of the shaft (125B); and
a rotor assembly (108) of the electric motor affixed to the second part of the shaft (125B) and borne by bearings (102) of the transmission system such that the electric motor in the second portion (105) of the integrated housing (120) is devoid of bearings.

2. The integrated assembly (100) as claimed in claim 1 wherein the first part of a shaft (125A) is mounted between two bearings (102) in a first portion (110) of the integrated housing (120); and
a second part of the shaft (125B) is located in a second portion (105) of the integrated housing (120).

3. The integrated assembly (100) as claimed in Claim 1, wherein the first part of the shaft (125A) is configured for being mounted with a primary element (112) of the transmission system.

4. The integrated assembly (100) as claimed in Claim 1, wherein the second part of the shaft (125B) is configured for receiving the rotor assembly (108) coaxial with a stator assembly (114) of the electric motor.
5. The integrated assembly (100) as claimed in Claim 1, wherein the first portion (110) and second portion (105) of the integrated housing (120) are fastened using a fastening mechanism.

6. The integrated assembly (100) as claimed in Claim 1, wherein the first portion (110) and the second portion (105) are separated by a separator (116) which is one or more of an integral part of the first portion (110) and a second portion (105) and through which passes the second portion of the shaft (125).

7. The integrated assembly (100) as claimed in Claim 1, wherein the second part of the shaft (125B) comprises:
a key-slot for receiving a key; and
a circular stopper radially extending from the shaft, for preventing an axial motion of the rotor assembly (108).

8. The integrated assembly (100) as claimed in Claim 1, wherein the electric motor comprises:
the rotor assembly (108) mounted on the second part of the shaft (125B) through one of bolting and interference fitting; and
a stator assembly (114) is mounted inside the second portion (105) of the integrated housing (120) and the separator (116) and the wiring for the stator is brought out of the second portion (105) of the integrated housing (120) through an aperture, fitted with a grommet (118) for preventing water ingress.

9. The integrated assembly (100) as claimed in Claim 1, wherein the rotor assembly (108) comprises:
a hollow cylindrical coupler, assembled on to the shaft and held in place by the key in the key-slot;
a balancing plate coupled to a rotor core; and
the rotor core is interference-fit on to the coupler.

10. The integrated assembly (100) as claimed in Claim 1, wherein the stator assembly (114) comprises a stator core and stator windings for producing a rotating magnetic field when supplied with appropriate electrical power, wherein the stator assembly (114) is held inside the second portion (105) of the integrated housing (120) through fasteners.

11. The integrated assembly (100) as claimed in Claim 1, wherein an output shaft of the transmission system extends out of the portion of the integrated housing (120) and is rotatably sealed with a shaft seal for preventing fluid ingress.

12. The integrated assembly (100) as claimed in Claim 1, wherein wiring for the encoder printed circuit (106) is brought out of an aperture, fitted with a grommet (118) for preventing fluid ingress.