WO2024150253A1

WO2024150253A1 - A hub motor assembly

Info

Publication number: WO2024150253A1
Application number: PCT/IN2024/050030
Authority: WO
Inventors: Yogesh Devidas Patil; Chidambaram SUBRAMONIAM; Soumya Saxena
Original assignee: TVS Motor Co Ltd
Current assignee: TVS Motor Co Ltd
Priority date: 2023-01-13
Filing date: 2024-01-11
Publication date: 2024-07-18
Anticipated expiration: 2025-07-13
Also published as: EP4648981A1

Abstract

A hub motor assembly (100) comprises a motor shaft (102) and a stator mounted concentrically on the motor shaft (102). The hub motor assembly (100) comprises a rotor mounted on the stator. The rotor is adapted to rotate relatively about the stator and the motor shaft (102). The hub motor assembly (100) comprises a rotor rim (104) mounted concentrically on the rotor. The rotor rim (104) is adapted to rotate synchronously with the rotor. The hub motor assembly (100) comprises a motor cover (106) mounted onto the rotor rim (104). The motor cover (106) is adapted to enclose the stator, the rotor, and the motor shaft (102). The hub motor assembly (100) comprises a breather valve (124) mounted on the motor cover (106). The breather valve (124) is adapted to provide ventilation to the hub motor assembly (100).

Description

TITLE OF INVENTION

A Hub Motor Assembly

FIELD OF THE INVENTION

[001] Present invention relates to a hub motor assembly.

BACKGROUND OF THE INVENTION

[002] Vehicles such as Electric Vehicles (EVs) or Hybrid-Electric Vehicles (HEVs) comprise a motor assembly as a driving component. The motor assembly is coupled to a wheel of the vehicle, for transferring torque required for movement of the vehicle. The motor assembly is coupled to the wheel through a transmission unit for driving the vehicle. However, the motor assembly with the transmission unit is typically bulky and is maintenance prone. To overcome these limitations in the motor assembly, a hub motor assembly is typically provided in the vehicle.

[003] The hub motor assembly comprises a stator and a rotor mounted onto a motor shaft. The stator is coupled to a battery module through motor wires that extend through the motor shaft. A motor cover is also provided for enclosing the stator, the rotor and the motor shaft. A rim surface is provided on the motor cover for supporting the wheel of the vehicle. As such, the hub motor assembly is directly mounted onto the wheel of the vehicle for torque transmission. Moreover, a geartrain assembly is also provided within the motor cover, thereby eliminating the requirement of the transmission unit in the vehicle, making the hub motor assembly compact.

[004] However, the conventional hub motor assembly has high probability of water seepage through a periphery of the motor cover (i.e. , to the stator and the rotor) or through an opening provided in the motor shaft for routing the motor wires. To overcome the water seepage issue, an adhesive layer is typically coated along the periphery of the motor cover and onto the opening on the motor shaft. However, coating of the adhesive layer blocks breathing or ventilation of the hub motor assembly. Breathing or ventilation of the motor refers to replacement of cold air with heated air, wherein the heated air is generated due to heat produced by high current carrying wires. The replacement or exchange of cold air with the heated air cools the motor and the high current carrying wires. As such, when the ventilation of the hub motor assembly is blocked, the heated air remains trapped within the hub motor assembly. The heated air upon condensation due to cooling causes moisture to be deposited on electrical components in the hub motor assembly such as copper and printed circuit boards. The moisture deposition on these electrical components causes corrosion, which is undesirable.

[005] Thus, there is a need for a hub motor assembly, which addresses at least one or more aforementioned problems.

SUMMARY OF THE INVENTION

[006] In one aspect of the invention, a hub motor assembly comprises a motor shaft and a stator mounted concentrically on the motor shaft. The hub motor assembly further comprises a rotor mounted on the stator and the rotor being adapted to rotate relatively about the stator and the motor shaft. Further, the hub motor assembly comprises a rotor rim mounted concentrically on the rotor wherein the rotor rim being adapted to rotate synchronously with the rotor. The hub motor assembly further comprises a motor cover mounted onto the rotor rim wherein the motor cover being adapted to enclose the stator, the rotor, and the motor shaft. The hub motor assembly further comprises a breather valve mounted on the motor cover wherein the breather valve being adapted to provide ventilation to the hub motor assembly.

[007] In an embodiment, the motor cover is mounted on an inner peripheral surface of the rotor rim such that the motor cover along with the rotor rim is adapted to enclose the stator, the rotor, and the motor shaft.

[008] In an embodiment, the breather valve comprises a stem portion and a head portion. The stem portion is disposed within the motor cover, while the head portion is positioned on an outer surface of the motor cover upon mounting of the breather valve on the motor cover.

[009] In an embodiment, the hub motor assembly comprises a first adhesive layer provided between the inner peripheral surface of the rotor rim and the motor cover. The first adhesive layer is adapted to seal the inner peripheral surface of the rotor rim and the motor cover for providing ingress protection to the hub motor assembly.

[010] In an embodiment, the first adhesive layer is made of a silicon-based material.

[011] In an embodiment, the motor shaft comprises a first end portion extending outwardly from the motor cover. Further, the first end portion of the motor shaft extends outwardly from the motor cover through an opening of the motor cover.

[012] In an embodiment, the hub motor assembly comprises a second adhesive layer provided at an interface portion between the opening and the first end portion of the motor shaft. The second adhesive layer is adapted to seal the interface portion for providing ingress protection to the hub motor assembly.

[013] In an embodiment, the second adhesive layer is made of a silicon-based material.

[014] In an embodiment, the hub motor assembly comprises a plurality of wires coupled to at least one of the stator and the rotor. The plurality of wires is routed into the hub motor assembly through an aperture provided to a first end portion of the motor shaft. [015] In an embodiment, the plurality of wires comprises one or more motor wires coupled to the stator and to a power source. The one or more motor wires is adapted to supply electric current to the stator from the power source for enabling rotation of the rotor. The plurality of wires further comprises one or more sensor wires that is coupled to at least one of the stator and the rotor. The one or more sensor wires is adapted to monitor one or more operating parameters of the hub motor assembly.

[016] In an embodiment, the hub motor assembly comprises a protective sleeve extending outwardly from the aperture of the motor shaft. The protective sleeve is adapted to encompass each of the plurality of wires for providing ingress protection to the hub motor assembly.

[017] In an embodiment, the protective sleeve is provided with a mouth portion that is adapted to allow routing of the plurality of wires through the protective sleeve for coupling with at least one of the stator and the rotor.

[018] In an embodiment, the hub motor assembly comprises a third adhesive layer that is provided at an intersection portion between the mouth portion and the plurality of wires. The third adhesive layer is adapted to seal the intersection portion for providing ingress protection to the hub motor assembly.

[019] In an embodiment, the third adhesive layer is made of a silicon-based material.

[020] In an embodiment, the protective sleeve extends outwardly by at least 100 mm of length from the aperture and is made of a Poly Vinyl Chloride (PVC) material.

[021] In an embodiment, the breather valve is disposed on an outer circumference of the motor cover.

BRIEF DESCRIPTION OF THE DRAWINGS [022] Reference will be made to embodiments of the invention, examples of which may be illustrated in accompanying figures. These figures are intended to be illustrative, not limiting. Although the invention is generally described in context of these embodiments, it should be understood that it is not intended to limit the scope of the invention to these particular embodiments.

Figure 1 is a perspective view of a hub motor assembly of a vehicle, in accordance with an embodiment of the present invention.

Figure 2 is a perspective view of the hub motor assembly of the Figure 1 , in accordance with an embodiment of the present invention.

Figure 3 is a perspective view of the hub motor assembly of the Figure 1 , in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[023] The present invention relates to a vehicle having a hub motor assembly. The hub motor assembly in the present invention is adapted to ensure sealing of a motor cover, while facilitating ventilation in the hub motor assembly.

[024] Figure 1 illustrates a schematic view of a hub motor assembly 100 in accordance with an embodiment of the present invention. The hub motor assembly 100 comprises a motor shaft 102. A stator (not shown) is coupled to the motor shaft 102. In the present embodiment, the stator is concentrically coupled to the motor shaft 102. A rotor (not shown) is mounted on the stator and is adapted to rotate relatively about the stator and the motor shaft 102. In the present embodiment, the rotor is mounted concentrically onto the stator and the motor shaft 102. In an embodiment, the rotor may be a rotor cup that encloses a magnet (not shown) and the stator. [025] Further, plurality of wires 114, 116 are coupled to at least one of the stator and the rotor, and to a battery module (not shown). The plurality of wires 114, 116 is adapted to supply power to at least one of the stator and the rotor for enabling rotation of the rotor. In the present embodiment, the plurality of wires 114, 116 is coupled to the stator and the battery module. Accordingly, the plurality of wires 114, 116 supply power to the stator from the battery module. The stator induces electromagnetic field, upon receiving power from the battery module, resulting in rotation of the rotor. In an embodiment, the battery module provides an Alternating Current (AC) power supply or a Direct Current (DC) power supply for inducing the electromagnetic field in the hub motor assembly 100. Accordingly, the hub motor assembly 100 of the present invention can be an AC hub motor or a DC hub motor. The plurality of wires 114, 116 are routed into the hub motor assembly 100 for electrically coupling with at least one of the stator and the rotor through an aperture 112 provided in the motor shaft 102. In an embodiment, shape and size of the aperture 112 corresponds to the size of the plurality of wires 114, 116.

[026] Referring to Figures 2 and 3 in conjunction with Figure 1 , a rotor rim 104 is mounted concentrically on the rotor. As such, rotation of the rotor results in rotation of the rotor rim 104. In an embodiment, the rotor rim 104 is a drum-type rotor rim 104 mounted onto the rotor. In an embodiment, the rotor rim 104 is mounted on to the rotor by conventional mounting techniques, such as fastening, known in the art. In an embodiment, the rotor rim 104 may be integrally formed on an outer surface of the rotor. The rotor rim 104 is capable of supporting a wheel (not shown) of a vehicle (not shown). As such, rotation of the rotor rim 104, enables rotation of the wheel, thereby ensuring movement of the vehicle.

[027] Further, the hub motor assembly 100 comprises a motor cover 106 adapted to enclose the stator, the rotor, and the motor shaft 102. The motor cover 106 is mounted on an inner peripheral surface 126 of the rotor rim 104. As a result, the motor cover 106 along with the rotor rim 104 is adapted to enclose the stator, the rotor, and the motor shaft 102. In one embodiment, the motor cover 106 is mounted on the inner peripheral surface 126 of the rotor rim 104 using conventional mounting techniques such as fastening, known in the art. In an embodiment, the motor cover 106 comprises a front motor cover (not depicted in Figures) mounted onto a front side of the rotor rim, and a rear motor cover (not shown) mounted onto a rear side of the rotor rim. Upon mounting the motor cover 106 onto the inner peripheral surface 126, a gap (not shown) may be formed between the motor cover 106 and the inner peripheral surface 126, through which water seepage may occur into the assembly 100 . Thus, for ensuring sealing or for ingress protection between the motor cover 106 and the rotor rim 104, a first adhesive layer 122 is provided. The first adhesive layer 122 is coated between the inner peripheral surface 126 of the rotor rim 104 and an outer circumference 128 of the motor cover 106. As a result, the first adhesive layer 122 ensures insulation or sealing from at least water and dust particles between the motor cover 106 and the rotor rim 104. In an embodiment, the first adhesive layer 122 is made of a silicon-based material. In an embodiment, silicon-based material is selected as the first adhesive layer 122 due to non-reactive characteristic of the material.

[028] The hub motor assembly 100 further comprises a breather valve 124 mounted on the motor cover 106. The breather valve 124 is adapted to provide ventilation to the motor cover 106. As a result, heated air formed within the motor cover 106 during operation of the hub motor assembly 100 is discharged by the breather valve 124 to surroundings, thereby preventing condensation within the motor cover 106. Consequently, preventing corrosion of components within the motor cover 106. In the present embodiment, the breather valve 124 is positioned proximal to a fastening member (not shown) at the outer circumference 128 of the motor cover 106, on the outer surface 106a of the motor cover

106. In an embodiment, the breather valve 124 is a one-way valve adapted to allow discharge of the heated air from the motor cover 106 to the surroundings, while preventing entry of air from the surroundings into the motor cover 106.

[029] In an embodiment, the breather valve 124 comprises an inlet opening (not shown) fluidically coupled to a nozzle opening (not shown) upon mounting of the breather valve 124 onto the motor cover 106. The breather valve 124 also comprises an outlet opening (not shown) for discharging the heated air from the motor cover 106 to the surroundings. A valve mechanism (not shown) is further provided in the breather valve 124. The valve mechanism is adapted to ensure fluid communication between the inlet opening and the outlet opening, when pressure of a fluid entering the inlet opening exceeds a preset pressure in the valve mechanism. Accordingly, upon mounting of breather valve 124, the heated air enters the inlet opening through the nozzle opening. When the pressure of the heated air exceeds the preset pressure in the valve mechanism, the heated air is discharged through the outlet opening.

[030] In the present embodiment, the breather valve 124 comprises a stem portion 124a and a head portion 124b. The stem portion 124a is disposed within the motor cover 106 upon mounting of the breather valve 124 on the motor cover 106. The head portion 124b is mounted on the outer surface 106a of the motor cover 106 upon mounting of the breather valve 124 on the motor cover 106.

[031] In an embodiment, the breather valve 124 is inserted into the nozzle opening such that, the stem portion 124a is disposed within the motor cover 106 while the head portion 124b rests on the outer surface 106a of the motor cover 106. In one embodiment, the breather valve 124 is mounted on the motor cover 106 through conventional mounting techniques such as press-fitting or fastening known in the art.

[032] Further, the motor shaft 102 comprises a first end portion 102a and a second end portion 102b. The first end portion 102a is adapted to extend on a left-side of the motor cover 106, while the second end portion 102b extends from a right-side of the motor cover 106. The first end portion 102a and the second end portion 102b extend outwardly from the motor cover 106 through an opening 108 of the motor cover 106. In the present disclosure, the opening 108 provided on the left-side of the motor cover 106 is depicted for ease of understanding. At an interface portion between the opening 108 and the first end portion 102a, a second adhesive layer 110 is provided. The second adhesive layer 110 is adapted to seal the interface portion, thereby ensuring ingress protection between the opening 108 and the first end portion 102a. In one embodiment, the second adhesive layer 110 is made of a silicon-based material. In an embodiment, the second adhesive layer 110 is also provided at the interface portion between the opening 108 and second end portion 102b, for ensuring ingress protection.

[033] In an embodiment, the plurality of wires 114, 116 extends from the first end portion 102a and/or the second end portion 102b of the motor shaft 102. In the present embodiment, the plurality of wires 114, 116 extends from the first end portion 102a of the motor shaft 102. A protective sleeve 118 extends outwardly from the aperture 112 of the motor shaft 102. The protective sleeve 118 is adapted to protect the plurality of wires 114, 116 against abrasion and environmental stress. The protective sleeve 118 is provided with a mouth portion 118a. The mouth portion 118a is adapted to allow routing of the plurality of wires 114, 116 through the protective sleeve 118 for coupling with at least one of the stator and the rotor. In an embodiment, the protective sleeve 118 may be tubular in shape. In one embodiment, the protective sleeve 118 extends outwardly from the aperture 112 by at least 100 mm of length. In another embodiment, the protective sleeve 118 is made of a Poly Vinyl Chloride (PVC) material.

[034] The plurality of wires 114, 116 may be of varying diameters and water may seep into the protector sleeve 118 through the mouth portion 118a. Therefore, a third adhesive layer 120 is provided at an intersection point between the mouth portion 118a and the plurality of wires 114, 116. The third adhesive layer 120 is adapted to seal the intersection point for providing ingress protection between the mouth portion 118a and the plurality of wires 114, 116. In one embodiment, the third adhesive layer 120 is made of a silicon- based material.

[035] In another embodiment, the plurality of wires 114, 116 further comprises one or more motor wires 114 and one or more sensor wires 116. The one or more motor wires 114 are coupled to the stator and to the battery module. The one or more sensor wires 116 are coupled to at least one of the stator and the rotor. The one or more sensor wires 116 are adapted to monitor one or more operating parameters of the hub motor assembly 100. In an embodiment, the one or more operating parameters monitored by the one or more sensor wires 116 may be one of a temperature, a Revolutions Per Minute (RPM) of the rotor, a voltage supplied to the stator and a current supplied to the stator.

[036] In an embodiment, the first adhesive layer 122, the second adhesive layer 110, and the third adhesive layer 120 are configured to provide ingress protection to the hub motor assembly 100 at respective interface portions and intersection points in the hub motor assembly 100.

[037] The claimed invention as disclosed above is not routine, conventional or well understood in the art, as the claimed aspects enable the following solutions to the existing problems in conventional technologies. Specifically, the claimed aspect of providing the breather valve disposed on the motor cover, is adapted to provide ventilation to the motor cover. As a result, heated air formed within the motor cover during operation of the hub motor assembly is discharged by the breather valve to the surroundings, thereby preventing condensation within the motor cover. Consequently, preventing corrosion of components within the motor cover. Further, the aspect of providing the first adhesive layer, the second adhesive layer, and the third adhesive layer is configured to provide ingress protection to the hub motor assembly at respective interface portions and intersection points in the hub motor assembly. Additionally, the protective sleeve for the plurality of wires, ensures protection to the plurality of wires against abrasion and environmental stress.

[038] While the present invention has been described with respect to certain embodiments, it will be apparent to those skilled in the art that various changes and modification may be made without departing from the scope of the invention as defined in the following claims.

List of Reference Numerals

100 - Hub motor assembly

102 - Motor shaft

102a - First end portion of motor shaft

102b - Second end portion of motor shaft

104 - Rotor rim

106 - Motor cover

106a - Outer surface of motor cover

108 - Opening

110 - Second adhesive layer

112 - Aperture

114 - One or more motor wires

116 - One or more sensor wires

114, 116 - Plurality of wires

118 - Protective sleeve 118a - Mouth portion

120 - Third adhesive layer

122 - First adhesive layer

124 - Breather valve 124a - Stem portion of breather valve

124b - Head portion of breather valve 126 - Inner peripheral surface of rotor rim 128 - Outer circumference of motor cover

Claims

CLAIMS:

1 . A hub motor assembly (100) comprising: a motor shaft (102); a stator mounted concentrically on the motor shaft (102); a rotor mounted on the stator, the rotor being adapted to rotate relatively about the stator and the motor shaft (102); a rotor rim (104) mounted concentrically on the rotor, the rotor rim (104) being adapted to rotate synchronously with the rotor; a motor cover (106) mounted onto the rotor rim (104), the motor cover (106) being adapted to enclose the stator, the rotor, and the motor shaft (102); and a breather valve (124) mounted on the motor cover (106), the breather valve (124) being adapted to provide ventilation to the hub motor assembly (100).

2. The hub motor assembly (100) as claimed in claim 1 , wherein the motor cover (106) is mounted on an inner peripheral surface (126) of the rotor rim (104), the motor cover (106) along with the rotor rim (104) being adapted to enclose the stator, the rotor, and the motor shaft (102).

3. The hub motor assembly (100) as claimed in claim 2, wherein the breather valve (124) comprises a stem portion (124a) and a head portion (124b), the stem portion (124a) being disposed within the motor cover (106), while the head portion (124b) being positioned on an outer surface (106a) of the motor cover (106), upon mounting of the breather valve (124) on the motor cover (106).

4. The hub motor assembly (100) as claimed in claim 3 comprises a first adhesive layer (122) provided between the inner peripheral surface (126) of the rotor rim (104) and the motor cover (106), the first adhesive layer (122) being adapted to seal the inner peripheral surface (126) of the rotor rim (104) and the motor cover (106) for providing ingress protection to the hub motor assembly (100).

5. The hub motor assembly (100) as claimed in claim 4, wherein the first adhesive layer (122) being made of a silicon-based material.

6. The hub motor assembly (100) as claimed in claim 3, wherein the breather valve (124) being disposed on an outer circumference (128) of the motor cover (106).

7. The hub motor assembly (100) as claimed in claim 1 , wherein the motor shaft (102) comprises a first end portion (102a) extending outwardly from the motor cover (106) through an opening (108) of the motor cover (106).

8. The hub motor assembly (100) as claimed in claim 7 comprises a second adhesive layer (110) provided at an interface portion between the opening (108) and the first end portion (102a) of the motor shaft (102), the second adhesive layer (110) being adapted to seal the interface portion for providing ingress protection to the hub motor assembly (100).

9. The hub motor assembly (100) as claimed in claim 8, wherein the second adhesive layer (110) being made of a silicon-based material.

10. The hub motor assembly (100) as claimed in claim 1 comprises a plurality of wires (114, 116) coupled to at least one of the stator and the rotor, the plurality of wires (114, 116) being routed into the hub motor assembly (100) through an aperture (112) provided to a first end portion (102a) of the motor shaft (102).

11 . The hub motor assembly (100) as claimed in claim 10, wherein the plurality of wires (114, 116) comprises: one or more motor wires (114) coupled to the stator and to a power source, the one or more motor wires (114) being adapted to supply electric current to the stator from the power source for enabling rotation of the rotor; and one or more sensor wires (116) being coupled to at least one of the stator and the rotor, the one or more sensor wires (116) being adapted to monitor one or more operating parameters of the hub motor assembly (100).

12. The hub motor assembly (100) as claimed in claim 10 comprises a protective sleeve (118) extending outwardly from the aperture (112) of the motor shaft (102), the protective sleeve (118) being adapted to encompass each of the plurality of wires (114, 116) for providing ingress protection to the hub motor assembly (100).

13. The hub motor assembly (100) as claimed in claim 12, wherein the protective sleeve

(118) being provided with a mouth portion (118a), the mouth portion (118a) being adapted to allow routing of the plurality of wires (114, 116) through the protective sleeve (118) for coupling with at least one of the stator and the rotor.

14. The hub motor assembly (100) as claimed in claim 13 comprises a third adhesive layer (120) being provided at an intersection portion between the mouth portion (118a) and the plurality of wires (114, 116), the third adhesive layer (120) being adapted to seal the intersection portion for providing ingress protection to the hub motor assembly (100).

15. The hub motor assembly (100) as claimed in claim 14, wherein the third adhesive layer (120) being made of a silicon-based material. 16. The hub motor assembly (100) as claimed in claim 12, wherein the protective sleeve (118) extends outwardly by at least 100 mm of length from the aperture (112) and being made of a Poly Vinyl Chloride (PVC) material.