Description:Complete Specification:
The following specification describes and ascertains the nature of this invention and the manner in which it is to be performed:

Field of the invention:
[0001] The present disclosure relates a sealing assembly for an electrical cable of a drive motor, an electrical cable for the drive motor and method of sealing the electrical cable.

Background of the invention:
[0002] In drive motors for two wheeler and other types of vehicles, water entry into drive motors is a serious problem. It may lead to incipient malfunctions and may lead to rusting inside the motor followed by seizing of the motor. In the existing design, the water cannot enter from the motor area (seals, shaft, cover etc.), but the cable harness that connects the motor to the motor control unit is not IP67 certified. The harness is intentionally kept this way for ensuring the durability of the motor considering the benefits of the breathing feature. However, currently the breathing capability is also resulting in water entering the motor during heavy rain / high pressure water wash.

[0003] Solution currently used in the market is to inject glue into the opening of the harness to a certain depth (upto 5 cm) to seal the connection end 204 of the electrical cable 114. But this solution has potential durability concerns, and the effectiveness solely depends on the quality of the glue used. This concept is also sealing the motor completely removing the breathing function of the harness. The glue will also have to handle road vibrations, high temperature operation (>100degC) and its effectiveness across the life of the motor is not known now. Jelly filled cable harnesses are also available, but seldom used as it is expensive.

[0004] According to a prior art DE2927558 discloses a watertight grip and cable termination - has stripped back conductors and sheath which are enclosed and vulcanised as is grip to appts. A grip and water tight connection for the lead of electrical equipment, esp. for motor vehicle instrumentation. The connection comprises a thermoplastic grommet vulcanised onto the end of the electrical lead and with a sleeved section as an extension for each individual insulated conductor in the cable. The cable is fed into the end of the sleeve grommet so that the outer sheath of the cable is gripped and protected. Each insulated individual stranded conductor is stripped back so that the insulated part feeds forward into the extensions of the sleeve grommet unit. The bared stranded conductor extending from the grommet extensions are further protected by collars slipped over the ends and glued or vulcanised to the main grommet unit. The outer surface of the sleeve grommet is moulded into ring formation to permit vulcanised sealing to in casing of the equipment at the input point.

Brief description of the accompanying drawings:
[0005] An embodiment of the disclosure is described with reference to the following accompanying drawings,
[0006] Fig. 1 illustrates a sealing assembly for an electrical cable of drive motor, according to an embodiment of the present invention;
[0007] Fig. 2 illustrates a perspective view of the assembled sealing for the electrical cable of the drive motor, according to an embodiment of the present invention, and
[0008] Fig. 3 illustrates a flow diagram of method for sealing an exposed end of the electrical cable of the drive motor, according to the present invention.

Detailed description of the embodiments:
[0009] Fig. 1 illustrates a sealing assembly for an electrical cable of drive motor, according to an embodiment of the present invention. The electrical cable 114 comprises multiple conductors 102 with respective insulation and all covered by sheath 108 (also known as outer sheath). The multiple conductors 102 are partially exposed out of the insulation and sheath 108 for connection to battery, control unit of the vehicle. The sealing assembly 100 comprises, a sealing member 112 (also known as breakout boot), a first portion 106 having an inlet and a second portion 104 having multiple outlets. The sealing member 112 is slidably inserted over the electrical cable 114 through the first portion 106 in such a manner that the first portion 106 covers the sheath 108 of the electrical cable 114 and the multiple conductors 102 of the electrical cable 114 passes through the multiple outlets of the second portion 104. The sealing member 112 is made of heat shrink tube which on application of heat, shrinks the first portion 106 and the second portion 104 and seals a gap between the sealing member 112 and the electrical cable 114 (any gaps therein), characterized in that, at least one air flow path 110 formed between the first portion 106 of the sealing member 112 and the sheath 108 of the electrical cable 114.

[0010] In Fig. 1 two views are shown. A first view 116 shows the sealing member 112, fixed at an open/connection end 204 (shown in Fig. 2) of the electrical cable 114. A second view 118 shows a cut-section view of the sealing member 112 fixed at the open/connection end 204 of the electrical cable 114. The electrical cable 114 is a multicore cable having at least two or more conductors 102. The conductors 102 are insulated and partially stripped at the open/connection end 204 with which a connection is to be made. Thus, the conductor 102, the insulator and sheath 108 are together called as the electrical cable 114. Between the sheath 108 and the conductors 102, there is air gap which is present throughout the length of the electrical cable 114.

[0011] According to an embodiment of the present invention, the at least one air flow path 110 is along the first portion 106 and communicates with air gap within the electrical cable 114. According to another embodiment, an adhesive material is filled in between the sealing member 112 and the electrical cable 114 before application of heat. According to yet another embodiment, at least one air flow path 110 is formed in a straight line or curved line. The at least one air flow path 110 starts from the input end of the first portion 106, extends within or internal to the first portion 106 till the start of the second portion 104 and then connects with the air gap of the electrical cable 114.

[0012] According to an embodiment of the present invention, the at least one air flow path 110 is formed by insertion of an element (not shown) between the first portion 106 of the sealing member 112 and the sheath 108 of the electrical cable 114 before application of heat and removal of the element after application of heat. The element functions as placeholder which is positioned before the application of heat and then pulled out after the heat shrink process is completed as per requirement.

[0013] According to an embodiment of the present invention, the electrical cable 114 of the drive motor is provided or the drive motor with the electrical cable 114 is provided. The electrical cable 114 comprises multiple conductors 102 with respective insulation and all covered by sheath 108. The multiple conductors 102 are partially exposed out of the insulation and sheath 108 for connection. The electrical cable 114 comprises the sealing member 112 (also known as breakout boot) having the first portion 106 with the inlet and the second portion 104 with multiple outlets. The sealing member 112 is slidably inserted over the electrical cable 114 through the first portion 106 in such a manner that the first portion 106 covers the sheath 108 of the electrical cable 114, and the multiple conductors 102, partially exposed, passes through the multiple outlets of the second portion 104. The sealing member 112 is made of heat shrink tube which on application of heat, shrinks the first portion 106 and the second portion 104 and seals any gap therein or on which it is inserted, characterized in that, the at least one air flow path 110 formed between the first portion 106 of the sealing member 112 and the sheath 108 of the electrical cable 114.

[0014] According to an embodiment of the present invention, the at least one air flow path 110 is formed in any one of the straight line and curved line. The at least one air flow path 110 is in flow communicates with air gap within the electrical cable 114. According to another embodiment, the adhesive material is filled in between the sealing member 112 and the electrical cable 114 before application of heat. According to yet another embodiment, the at least one air flow path 110 is formed by insertion of the element between the first portion 106 of the sealing member 112 and the sheath 108 of the electrical cable 114 before application of heat, and removal of the element after application of heat.

[0015] According to an embodiment of the present invention, each of the air flow path 110 is formed with diameter 1 millimeter. In another embodiment, the at least one air flow path 110 comprises two air flow paths 110 formed diametrically opposite sides of the electrical cable 114. The size of the opening of the at least one air flow path 110 and the number of air flow path 110 are designed as per requirement and not limited to the example provided.

[0016] According to an embodiment of the present invention, the drive motor is any one selected from a group comprising a hub motor or side mounted motor (having neodymium magnet) or as a motor mounted on the wheel of an electric vehicle or hybrid vehicle.

[0017] Fig. 2 illustrates a perspective view of the assembled sealing for the electrical cable of the drive motor, according to an embodiment of the present invention. The multicore conductor 102 are shown to be four in number, however this must not be understood in limiting manner. The multicore cable is possible to be two or more conductors 102. In Fig. 2, the at least one air flow path 110 is shown explicitly. The connection end 204 of the electrical cable 114 is away from an opening 202 of the at lease one air flow path 110.

[0018] According to an embodiment of the present invention, an application of the sealing assembly 100 is provided. Consider the sealing member 112 is filled with a jelly based adhesive. The sealing member 112 comprises one inlet and multiple outlets. Upon heating the sealing member 112 (which is the heat shrink tube), the sealing member 112 shrinks and attaches to the surface of the electrical cable 114 firmly. The sealing member 112 ensures that the there are no open gaps through which water can enter the electrical cable 114. The adhesive jelly inside the sealing member 112 ensures individual outlets (or break outs) are sealed well upon shrinking. These sealing member 112 works very well with high temperature operations and pose no threat for water entry.

[0019] According to the present invention, a process to seal using the sealing member 112 is provided. A first step comprises assembling the jelly-filled sealing member 112 (heat-shrinkable tube) before assembling the electrical cable 114. A next step comprises sealing the sealing member 112 to the electrical cable 114 using the heat shrinking process. The heat shrinking process is controlled in such a way that there is essential clearance provided at the entry part after heating. This retains the breathing capability of the electrical cable 114 of the drive motor. The electric cable 114 or the drive motor is subject to leakage test at the end of the motor assembly line to ensure sealing member 112 is fully sealed. The specific steps are defined in Fig. 3.

[0020] Fig. 3 illustrates a flow diagram of a method for sealing an exposed end of the electrical cable of the drive motor, according to the present invention. The method comprises plurality of steps of which a step 302 comprises inserting the sealing member 112 over a connection end 204 of the electrical cable 114. The sealing member 112 comprises the first portion 106 which covers sheath 108 of the electrical cable 114, and the second portion 104 with multiple outlet through which multiple conductors 102 of the electrical cable 114 passes. A step 304 comprises applying heat to the sealing member 112 to shrink and seal any gaps between the sealing member 112 and the electrical cable 114. The method is characterized by a step 306 which comprises inserting the element between the first portion 106 of the sealing member 112 and the sheath 108 of the electrical cable 114 before applying the heat. A step 308 comprises removing the element after the heat shrinking process is completed. The step 306 is done before step 306, and the step 308 is performed after the step 304.

[0021] According to an embodiment of the present invention, the sealing member 112 prevents water entry without losing the breathing capability of the drive motor. The sealing assembly 100 as per the present invention ensures no moisture is trapped inside the drive motor at the time of manufacturing, no pressure build-up inside the drive motor with temperature rise during operation, and air leakage test for the motor on the assembly line is very simple. The breathability of the drive motor is also retained.

[0022] It should be understood that embodiments explained in the description above are only illustrative and do not limit the scope of this invention. Many such embodiments and other modifications and changes in the embodiment explained in the description are envisaged. The scope of the invention is only limited by the scope of the claims.
, Claims:We claim:
1. A sealing assembly (100) for an electrical cable (114) of a drive motor, said electrical cable (114) comprising multiple conductors (102) with respective insulation and all covered by a sheath (108), said multiple conductors (102) are partially exposed out of said insulation and sheath for connection, said sealing assembly (100) comprises:
a sealing member (112) comprising a first portion (106) having an inlet and a second portion (104) having multiple outlets, said sealing member (112) is slidably inserted over said electrical cable (108) through said first portion (106) in such a manner that said first portion (106) covers said sheath (108) of said electrical cable (108) and said multiple conductors (102) passes through said multiple outlets of said second portion (104),
said sealing member (112) is made of heat shrink tube which on application of heat, shrinks said first portion (106) and said second portion (104) and seals any gap therein, characterized in that, at least one air flow path (110) formed between said first portion (106) of said sealing member (112) and said sheath (108) of said electrical cable (114).

2. The sealing assembly (100) as claimed in claim 1, wherein said at least one air flow path (110) is along said first portion (106) of said sealing member (112) and communicates with air gap within said electrical cable (114).

3. The sealing assembly (100) as claimed in claim 1, wherein an adhesive material is filled in between said sealing member (112) and said electrical cable (114) before application of heat.

4. The sealing assembly (100) as claimed in claim 1, wherein said at least one air flow path is formed in a straight line or curved line.

5. The sealing assembly (100) as claimed in claim 1, wherein said at least one air flow path (110) is formed by insertion of an element between said first portion (106) and said sheath (108) of said electrical cable (114) before application of heat and removal of said element after application of heat.

6. An electrical cable (114) of a drive motor, said electrical cable (114) comprises multiple conductors (102) with respective insulation and all covered by a sheath (108), said multiple conductors (102) are partially exposed out of said insulation and sheath (108) for connection, said electrical cable (114) comprises:
a sealing member (112) having a first portion (106) with an inlet and a second portion (104) with multiple outlets, said sealing member (112) is slidably inserted over said electrical cable (114) through said first portion (106) in such a manner that said first portion (106) covers said sheath (108) of said electrical cable (114), and said multiple conductors (102), partially exposed, passes through said multiple outlets of said second portion (104),
said sealing member (112) is made of heat shrink tube which on application of heat, shrinks said first portion (106) and said second portion (104) and seals any gap therein, characterized in that, at least one an air flow path (110) formed between said first portion (106) of said sealing member (112) and a sheath (108) of said electrical cable (114).

7. The electrical cable (114) as claimed in claim 6, wherein said at least one air flow path (110) is formed in a straight line or curved line, and wherein said at least one air flow path (110) is in flow communicates with air gap within said electrical cable (114).

8. The electrical cable (114) as claimed in claim 6, wherein an adhesive material is filled in between said sealing member (112) and said electrical cable (114) before application of heat.

9. The electrical cable (114) as claimed in claim 6, wherein said at least one air flow path (110) is formed by insertion of an element between said first portion (106) of said sealing member (112) and said electrical cable (114) before application of heat and removal of said element after application of heat.

10. A method for sealing an exposed end of an electrical cable (114) of a drive motor, said method comprising the steps of:
inserting a sealing member (112) over a connection end (204) of said electrical cable (114), said sealing member (112) comprises a first portion (106) which covers sheath (108) of said electrical cable (114), and a second portion (104) with multiple outlet through which passes multiple conductors (102) of said electrical cable (114),
applying heat to said sealing member (112) to shrink and seal any gaps therein, characterized by,
inserting an element between said first portion (106) of said sealing member (112) and said sheath (108) of said electrical cable (114) before applying said heat, and
removing said element after completion of the heat shrink process.