Claims:1. A drive assembly (120) for a vehicle (102) comprising an electrical machine (110) mounted to a wheel (104), said drive assembly (120) comprising:
a first stage (112) coupled to a rotor shaft (108) of said electrical machine (110), comprising a plurality of primary planet gears (204) intermeshing between a primary sun gear (206) and a primary ring gear (202), said plurality of primary planet gears (204) are coupled to a primary carrier (208), and
a second stage (114) comprising a plurality of secondary planet gears (214) intermeshing between a secondary sun gear (216) and a secondary ring gear (212), said plurality of secondary planet gears (214) are coupled to a secondary carrier (218),
characterized by,
said first stage (112) coupled as an input to said second stage (114), and said second stage (114) is coupled to said wheel (104).
2. The drive assembly (120) as claimed in claim 1, wherein output of said first stage (112) is taken from any one of said primary sun gear (206), said primary ring gear (202) and said primary carrier (208).

3. The drive assembly (120) as claimed in claim 1, wherein said second stage (114) is coupled to said wheel (104) by any one of said secondary sun gear (216), said secondary ring gear (212) and said secondary carrier (218).

4. The drive assembly (120) as claimed in claim 1, wherein said rotor shaft (108) of said electrical machine (110) is coupled to said primary sun gear (206) of said first stage (112), and said primary carrier (208) of said first stage (112) is coupled to said secondary sun gear (216) of said second stage (114), and said secondary carrier (218) of said second stage (114) is coupled to said wheel (104).

5. The drive assembly (120) as claimed in claim 1, wherein said rotor shaft (108) of said electrical machine (110) is coupled to said primary sun gear (206) of said first stage (112), and said primary carrier (208) of said first stage (112) is coupled to said secondary sun gear (216) of said second stage (114), and said secondary ring gear (212) of said second stage (114) is coupled to said wheel (104).

6. The drive assembly (120) as claimed in claim 1, wherein said rotor shaft (108) of said electrical machine (110) is coupled to said primary sun gear (206) of said first stage (112), and said primary ring gear (202) of said first stage (112) is coupled to said secondary sun gear (216) of said second stage (114), and said secondary carrier (218) of said second stage (114) is coupled to said wheel (104).

7. The drive assembly (120) as claimed in claim 1, wherein said rotor shaft (108) of said electrical machine (110) is coupled to said primary sun gear (206) of said first stage (112), and said primary ring gear (202) of said first stage (112) is coupled to said secondary sun gear (216) of said second stage (114), and said secondary ring gear (212) of said second stage (114) is coupled to said wheel (104).

8. The drive assembly (120) as claimed in claim 1, wherein said first stage (112), said second stage (114) and said electrical machine (110) are mounted to said wheel (104) in at least one manner selected from a group comprising, a first arrangement comprising said electrical machine (110), said first stage and said second stage coupled to a first side of said wheel (104), a second arrangement comprising said electrical machine (110) and said first stage (112) on said first side of said wheel (104) and said second stage (114) on a second side of said wheel (104), a third arrangement comprising said electrical machine (110) and said second stage (114) on said first side of said wheel (104) and said first stage (112) on said second side of said wheel (104), and a fourth arrangement comprising said electrical machine (110) on said first side, and said first stage (112) and the second stage (114) on said second side of said wheel (104).

9. The drive assembly (120) as claimed in claim 1, further comprises at least one third planetary stage coupling an output of said second stage (114) to said wheel (104).

10. The drive assembly (120) as claimed in claim 1 is retrofit to a wheel of an existing vehicle. , Description:Field of the invention:
[0001] The present invention relates to a drive assembly for a vehicle.
Background of the invention:
[0002] According to a patent US6590306, an electric motor driven wheel is disclosed. A motor scooter embodying an improved electric motor driven wheel. The electric motor for driving the wheel is quite compact and is designed so as to be nested within the disk of the wheel. The motor controller is mounted adjacent the wheel in a protected area but is cooled by airflow across it and by heat transfer to the motor housing. Oil in the motor assembly also will cool the controller. A two speed planetary gear transmission is employed that also is compact and can be nested easily within portions of the electric motor. In addition, an improved brake assembly is also mounted integrally within the motor driving mechanism.
Brief description of the accompanying drawings:
[0003] An embodiment of the disclosure is described with reference to the following accompanying drawing,
[0004] Fig. 1 illustrates a vehicle employed with a first configuration of a drive assembly, according to an embodiment of the present invention;
[0005] Fig 2 illustrates an exploded view of the first configuration of the drive assembly, according to an embodiment of the present invention;
[0006] Fig. 3 illustrates a simple schematic of the drive assembly in a second configuration, according to an embodiment of the present invention;
[0007] Fig. 4 illustrates a simple schematic of a third configuration of the drive assembly, according to an embodiment of the present invention;
[0008] Fig. 5 illustrates a simple schematic of a fourth configuration of the drive assembly, according to an embodiment of the present invention., and
[0009] Fig. 6 illustrates an alternative drive assembly, according to an embodiment of the present invention.
Detailed description of the embodiments:
[0010] Fig. 1 illustrates a vehicle employed with a drive assembly in first configuration, according to an embodiment of the present invention. The drive assembly 120 is provided for the vehicle 102 comprising an electrical machine 110 mounted to a wheel 104. The drive assembly 120 comprises a first stage 112 coupled to a rotor shaft 108 of the electrical machine 110 through a primary sun gear 206. The first stage 112 comprises a plurality of primary planet gears 204 intermeshing between the primary sun gear 206 and a primary ring gear 202. The plurality of primary planet gears 204 are coupled to a primary carrier 208. In the illustrated drive assembly 120, the first stage 112 and the second stage 114 are mounted beside the wheel 104, specifically to a first side or a second side of the wheel 104.
[0011] The vehicle 102 is selected from a group comprising a two wheeler such as motorcycle, scooter, etc, a three wheeler such as auto-rickshaws, a four wheeler such as cars and other types of vehicles comprising but not limited to snowmobiles.
[0012] The drive assembly 120 further comprises a second stage 114 comprising a plurality of secondary planet gears 214 intermeshing between a secondary sun gear 216 and a secondary ring gear 212. The plurality of secondary planet gears 214 are coupled to a secondary carrier 218. The drive assembly 120 is characterized by first stage 112 coupled as an input to the second stage 114, and the second stage 114 coupled to the wheel 104. The drive assembly 120 is shown mounted to the rear wheel 104, but is equally applicable for other wheels 104 of the vehicle 102.
[0013] Further, a bearing 118 inside a holder 116 may be provided between the first stage 112 and the second stage 114. A swing arm/fork (not shown) is mounted across the wheel 104. The output of the first stage 112 is taken from any one of the primary sun gear 206, the primary ring gear 202 and the primary carrier 208. The second stage 114 couples to the wheel 104 by any one of the secondary sun gear 216, the secondary ring gear 212 and the secondary carrier 218.
[0014] The first configuration of the drive assembly 120 is illustrated, where the rotor shaft 108 is coupled with the primary sun gear 206 of the first stage 112. The primary sun gear 206 is coupled to the primary ring gear 202 with intermediate plurality of primary planet gears 204. The primary carrier 208 is the output for the first stage 112. The output from the first stage 112 is the input to the secondary sun gear 216 of the second stage 114. The secondary sun gear 216 is coupled to the secondary ring gear 212 through the intermediate plurality of secondary planet gears 214. The secondary carrier 218 is coupled to the wheel 104, thereby coupling the plurality of secondary planet gears 214 to the wheel 104. In the first configuration, the primary ring gear 202 and the secondary ring gear 212 are internally fixed to the housing 222. The plurality of primary planet gears 204, and the plurality of secondary planet gears 214 are rotatable on respective axis and rotatable around the primary sun gear 206 and the secondary sun gear 216, respectively.
[0015] Fig 2 illustrates an exploded view of the first configuration of the drive assembly, according to an embodiment of the present invention. Only one set of bearing 118 and the holder 116 is shown which is in between the first stage 112 and the second stage 114. The bearing 118 provides support to the drive assembly 120. However, there are other sets, one within a housing 222 of the electrical machine 110, and the other set on the second side of the wheel 104. The holder 116 is again supported by the housing 222, to ensure the bearing 118 is fixed into location. The protrusion 220 is the location where the swing arm is mounted to, but must not be considered in limiting sense. The electrical machine 110 is coupled to the drive assembly 120 through the housing 222.
[0016] In one embodiment, the drive assembly 120 is integrated to the wheel 104. In another embodiment, the drive assembly 120 is integrated to the electrical machine 110. In still another embodiment, the drive assembly 120 is standalone unit, adaptable to be mounted to the wheel 104 and/or the electrical machine 110.
[0017] The other components such as controller to operate the electrical machine 110, coupling members, clutches, battery, and electrical connections are not shown for simplicity. The controller is either the Engine Control Unit (ECU) or a dedicated controller.
[0018] The output of the first stage 112 is taken from any one of the primary sun gear 206, the primary ring gear 202 and the primary carrier 208. Similarly, the second stage 114 couples to the wheel 104 by any one of the secondary sun gear 216, the secondary ring gear 212 and the secondary carrier 218. The drive assembly 120 is designed as per the requirement and as per the design of the vehicle 102.
[0019] Fig. 3 illustrates a simple schematic of the drive assembly in a second configuration, according to an embodiment of the present invention. In the second configuration, only rotor shaft 108 is shown without the electrical machine 110 for simplicity of understanding and explanation. The rotor shaft 108 is coupled to the primary sun gear 206 of the first stage 112. The output of the first stage 112 is same as Fig. 1, i.e. the primary carrier 208. The primary carrier 208 of the first stage 112 is coupled to the secondary sun gear 216 of the second stage 114. However, the output of the second stage 114 is secondary ring gear 212. The secondary ring gear 212 couples to the wheel 104 and transmits the torque generated by the electrical machine 110 to the wheel 104. The second configuration/ arrangement gives a lower gear reduction than the first configuration, where both the outputs are taken from the primary carrier 208 and the secondary carrier 218.
[0020] In the second configuration, the primary ring gear 202 is fixed to the housing 222, whereas the secondary ring gear 212 is rotatable on respective axis. The plurality of primary planet gears 204 are rotatable on respective axis and around the primary sun gear 206, whereas the plurality of secondary planet gears 214 are rotatable only on respective axis but fixed to respective position, i.e. not movable around the secondary sun gear 216. The secondary carrier 218 is in between the holder 116 and the second stage 114. The secondary carrier 218 is fixed to the housing 222.
[0021] The electrical machine 110 is any one selected from a group comprising a DC motor, BLDC motor, AC motor such as synchronous motor, etc. The present invention enables all types of electrical machines 110 whether AC or DC, and also irrespective of whether the electrical machine 110 is to be mounted on the chassis or to be mounted in the hub of the wheel 104.
[0022] Fig. 4 illustrates a simple schematic of a third configuration of the drive assembly, according to an embodiment of the present invention. In the third configuration, the rotor shaft 108 of the electrical machine 110 is coupled to the primary sun gear 206 of the first stage 112. The output of the first stage 112 is from the primary ring gear 202. The primary ring gear 202 of the first stage 112 is coupled to the secondary sun gear 216 of the second stage 114. The output of the second stage 114 is from the secondary carrier 218, which couples to the wheel 104. The third configuration/ arrangement gives the same gear reduction as the first configuration.
[0023] In the third configuration, the primary ring gear 202 is rotatable around the primary sun gear 206, whereas the secondary ring gear 212 is fixed to the housing 222. The plurality of primary planet gears 204 are rotatable in respective axis but not around the primary sun gear 206, whereas the plurality of secondary planet gears 214 are rotatable on respective axis and around the secondary sun gear 216.
[0024] Fig. 5 illustrates a simple schematic of a fourth configuration of the drive assembly, according to an embodiment of the present invention. In the fourth configuration, the rotor shaft 108 of the electrical machine 110 is coupled to the primary sun gear 206 of the first stage 112. The output from the first stage 112 is from the primary ring gear 202, which is coupled to the secondary sun gear 216 of the second stage 114. The output from the second stage 114 is from the secondary ring gear 212, coupling to the wheel 104. In the fourth configuration, the primary ring gear 202 and the secondary ring gear 212 are rotatable around the primary sun gear 206 and the secondary sun gear 216, respectively, and not affixed to the housing 222. On the other hand, the plurality of primary planet gears 204 and the plurality of secondary planet gears 214 are rotatable only on respective axis and not around the primary sun gear 206 and the secondary sun gear 216 respectively. The fourth configuration/ arrangement gives the lowest possible gear reduction as compared to aforementioned configurations.
[0025] Fig. 6 illustrates an alternative drive assembly, according to an embodiment of the present invention. In the alternate drive assembly 120, the first stage 112 and the second stage 114 is mounted to the first side and the second side of the wheel 104, respectively. In other words, the wheel 104 is mounted between the first stage 112 and the second stage 114. The output of the first stage 112 passes through the rotational axis of the wheel 104 and couples to the second stage 114. The output of the second stage 114 is coupled to the wheel 104 for driving the vehicle 102.
[0026] The configurations as explained in Fig. 1 through Fig. 5 is applicable to the alternative drive assembly 120 as well. In one embodiment, the electrical machine 110 is mounted to a chassis of the vehicle 102. Alternatively, the electrical machine 110 is mounted to the hub of the wheel 104.
[0027] In yet another embodiment, the first stage 112, the second stage 114 and the electrical machine 110 are mounted to said wheel 104 in at least one manner selected from a group comprising, a first arrangement comprising the electrical machine 110, the first stage 112, and the second stage coupled to the first side of the wheel 104, where the electrical machine 110 and the drive assembly 120 are on the same side, a second arrangement comprising the electrical machine 110 on and the first stage112 on the first side of the wheel 104 and the second stage 114 on the second side of the wheel 104 a third arrangement comprising the electrical machine 110 and the second stage 114 on the first side and the first stage 112 on the second side of the wheel 104, a fourth arrangement comprising the electrical machine 110 on the first side and the first stage 112 and the second stage 114 on the second side of the wheel 104.
[0028] In another embodiment, the drive assembly 120 comprises at least one third planetary stage coupling an output of the second stage 114 to the wheel 104, where the construction and configuration of the at least one third planetary stage is similar as the first stage 112 and the second stage 114, with or without changes necessary to accommodate to the wheel 104. The mounting location of the three or more stages is also similar to the mounting location described above for the two planetary stages 112, 114.
[0029] A working of the drive assembly 120 is provided. The drive assembly 120 with required size and shape of the first stage 112 and the second stage 114 is decided based on the electrical machine 110 and the type of mounted to the vehicle 102. The electrical machine 110 is supplied by power from a battery (not shown) and is controlled by a controller (not shown). The output of the electrical machine 110 is through the rotor shaft 108 which is coupled to the primary sun gear of the first stage 112. The output from the first stage 112 is the input to the second stage 114. The second stage 114 drives the wheel 104 of the vehicle 102.
[0030] In the present invention, among all configurations, the design of the two planetary stages 112, 114 remains the same. The only difference is in the output of both the stages 112, 114. The configuration is applicable for a series hybrid vehicle 102, parallel hybrid vehicle 102 and electric vehicle 102. Further, the motor is operatively used as generator to charge the batteries in above configurations as known in the art. The drive assembly 120 is provided integrated with the electrical machine 110. Alternatively, the drive assembly 120 and the electrical machine 110 are independently coupled to each other and then to the wheel 104 of the vehicle 102 such as but not limited a two wheeler. The proposed drive assembly 120 enables retro-fit to any generic motor allowing the motor to be mounted directly onto the wheel 104. The design of the drive assembly 120 is also adaptable to fit any rim size of the vehicle 102. In the present invention, the drive assembly 120 is a two stage fixed speed reduction planetary system which is designed to retrofit to any electrical machine 110, thus allowing the electrical machine 110 to be mounted directly onto the wheel 104, i.e. along the axis of the wheel 104 of the vehicle 102. A brake also can be integrated into the housing 222 of the drive assembly 120. Alternatively, a separate brake component is mounted on the other side of the wheel 104. The present invention also enables and allows any generic electrical machine 110 to be converted to a hub based electrical machine 110 such as a hub motor.
[0031] 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.