Description:FIELD OF THE INVENTION

[1] The present disclosure generally relates to a saddle-type vehicle. More particularly, the present disclosure relates to a powertrain of a saddle-type vehicle.

BACKGROUND

[2] The powertrain in a saddle-type vehicle, for example, an electric scooter, includes a gearbox and an electric motor. The electric motor draws energy from a battery and converts it to mechanical energy. The gearbox transfers mechanical power from the electric motor to the wheel.

[3] Typically, the electric motor and the gearbox unit is mounted near the wheel. In this configuration where the electric motor and the gearbox unit is mounted near the wheel, the entire powertrain mass is shifted to one side of the electric scooter. This impacts the overall dynamics of the vehicle and causes discomfort to the user.

[4] Further, when the motor is laterally shifted towards one side of the vehicle, the ergonomics of side steps are impacted. The lean angle of the vehicle is also restricted in this configuration. Further, the assembly of the brake lever poses a challenge in this configuration. Furthermore, the serviceability of the brake lever is a challenge in this configuration since the movement is limited by the hub offset of the wheel.

[5] One way to overcome the aforementioned problem is to reduce dimensions of the gearbox unit which includes an input shaft and an output shaft. However, reducing the dimensions of the gearbox unit decreases its overall durability. Additionally, the gearbox unit has a seal at both the input and output shaft, which further increases the lateral width of gearbox. Therefore, there is a need to reposition the gearbox layout in order to shift the motor inward, towards the vehicle center plane, without reducing the dimensions.

SUMMARY

[6] This summary is provided to introduce a selection of concepts, in a simplified format, that is further described in the detailed description of the invention. This summary is neither intended to identify key or essential inventive concepts of the invention and nor is it intended for determining the scope of the invention.

[7] An objective of the present disclosure is to optimize the lateral center of gravity (CG) of a saddle-type vehicle and specifically of an electric scooter, by reducing lateral offset of the powertrain, without compromising the assembly process and serviceability of brake lever.

[8] Another objective of the present disclosure is to reposition the gearbox layout in order to shift the motor inward, towards the vehicle center plane, so as to keep the CG close to the vehicle centerline.

[9] Accordingly, a powertrain for a saddle-type vehicle is disclosed. The powertrain includes a motor, an input shaft coupled to the motor and a support bearing coupled to the input shaft. The powertrain includes an input gear coupled to the input shaft and an output gear coupled to an output shaft. The support bearing is disposed proximate and co-planar to the output gear. The powertrain includes a first intermediate gear and a second intermediate gear, wherein the first and second intermediate gears are coupled to an intermediate shaft. The first intermediate gear and the second intermediate gear are engaged to the input gear and the output gear, respectively.

[10] 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

[11] 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:

[12] Figure 1 illustrates a perspective side view of a saddle-type vehicle, according to an embodiment of the present disclosure;

[13] Figure 2A illustrates a perspective view of a powertrain in a saddle-type vehicle, according to an embodiment of the present disclosure;

[14] Figure 2B illustrates a perspective view of helical gears in the powertrain, according to an embodiment of the present disclosure;

[15] Figure 2C illustrates a perspective view of the powertrain, according to an embodiment of the present disclosure;

[16] Figure 2D illustrates a perspective view of a gearbox unit of the powertrain, according to an embodiment of the present disclosure;

[17] Figure 2E illustrates a perspective view of brake lever in the powertrain, according to an embodiment of the present disclosure; and

[18] Figure 2F illustrates a perspective view of helical gears in the powertrain, according to an embodiment of the present disclosure.

[19] Further, skilled artisans will appreciate that elements in the drawings are illustrated for simplicity and may not have necessarily been drawn to scale. For example, the flow charts illustrate the method in terms of the most prominent steps involved to help to improve understanding of aspects of the present invention. Furthermore, in terms of the construction of vehicle, one or more components of the vehicle 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

[20] 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.

[21] 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.

[22] 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.”

[23] 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.

[24] 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.

[25] 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.

[26] 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.

[27] Embodiments of the present disclosure will be described below in detail with reference to the accompanying drawings.

[28] 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.

[29] An 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).

[30] In construction, as illustrated in Figure 1, an EV (10) typically comprises a battery or battery pack (12) enclosed within a battery casing and includes a Battery Management System (BMS), an on-board charger (14), a Motor Controller Unit (MCU), an electric motor (16) and a transmission system (18). The primary function of the above-mentioned elements is detailed in the subsequent paragraphs: The battery of an EV (10) (also known as Electric Vehicle Battery (EVB) or traction battery) is re-chargeable in nature and is the primary source of energy required for the operation of the EV, wherein the battery (12) is typically charged using the electric current taken from the grid through a charging infrastructure (20). The battery may be charged using Alternating Current (AC) or Direct Current (DC), wherein in case of AC input, the on-board charger (14) converts the AC signal to DC signal after which the DC signal is transmitted to the battery via the BMS. However, in case of DC charging, the on-board charger (14) is bypassed, and the current is transmitted directly to the battery via the BMS.

[31] The battery (12) is made up of a plurality of cells which are grouped into a plurality of modules in a manner in which the temperature difference between the cells does not exceed 5 degrees Celsius. The terms “battery”, “cell”, and “battery cell” may be used interchangeably and may refer to any of a variety of different rechargeable cell compositions and configurations including, but not limited to, lithium-ion (e.g., lithium iron phosphate, lithium cobalt oxide, other lithium metal oxides, etc.), lithium-ion polymer, nickel metal hydride, nickel cadmium, nickel hydrogen, nickel-zinc, silver zinc, or other battery type/configuration. The term “battery pack” as used herein may be referred to multiple individual batteries enclosed within a single structure or multi-piece structure. The individual batteries may be electrically interconnected to achieve a desired voltage and capacity for a desired application. The Battery Management System (BMS) is an electronic system whose primary function is to ensure that the battery (12) is operating safely and efficiently. The BMS continuously monitors different parameters of the battery such as temperature, voltage, current and so on, and communicates these parameters to the Electronic Control Unit (ECU) and the Motor Controller Unit (MCU) in the EV using a plurality of protocols including and not limited to Controller Area Network (CAN) bus protocol which facilitates the communication between the ECU/MCU and other peripheral elements of the EV (10) without the requirement of a host computer.

[32] The MCU primarily controls/regulates the operation of the electric motor based on the signal transmitted from the vehicle battery, wherein the primary functions of the MCU include starting of the electric motor (16), stopping the electric motor (16), controlling the speed of the electric motor (16), enabling the vehicle to move in the reverse direction and protect the electric motor (16) from premature wear and tear. The primary function of the electric motor (16) 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 (16) 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). In an embodiment, the motor (16) may be disposed near the rear wheel (22b).

[33] The transmission system (18) of the EV (10) facilitates the transfer of the generated mechanical energy by the electric motor (16) to the wheels (22a,22b) of the EV. Generally, the transmission systems (18) used in EVs include single speed transmission system and/or 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. In an embodiment, when the motor (16) is disposed near the rear wheel (22b), the transmission system (18) may be disposed between the motor (16) and the rear wheel (22b).

[34] In an embodiment, the motor (16) and the transmission system (18) may be collectively referred to as a powertrain.

[35] In one embodiment, all data pertaining to the EV (10) and/or charging infrastructure (20) are collected and processed using a remote server (known as cloud) (24), wherein the processed data is indicated to the rider/driver of the EV (10) through a display unit present in the dashboard (26) of the EV (10). In an embodiment, the display unit may be an interactive display unit. In another embodiment, the display unit may be a non-interactive display unit.

[36] Embodiments of the present disclosure describe a modified powertrain in the saddle-type vehicle (10) that includes the motor (16) and the transmission system (18).

[37] Figure 2A illustrates a perspective view of a powertrain (200) in the saddle-type vehicle (10), according to an embodiment of the present disclosure. The powertrain (200) includes a motor (205) and an input shaft (210). The input shaft (210) is coupled to the motor (205) and a support bearing (215) is coupled to the input shaft (210), whereby the support bearing (215) supports the input shaft (210). The powertrain (200) includes an input gear (220) coupled to the input shaft (210) and an output gear (225) coupled to an output shaft (230). The output shaft (230) is configured to drive a rear wheel (235). In an embodiment, the motor (205) may be similar to the motor (16) shown in Figure 1 and the rear wheel (235) may be similar to the rear wheel (22b) shown in Figure 1.

[38] The powertrain (200) includes a first intermediate gear (240a) and a second intermediate gear (240b), wherein the first and second intermediate gears (240a, 240b) are coupled to an intermediate shaft (250). The first intermediate gear (240a) and the second intermediate gear (240b) are engaged to the input gear (220) and the output gear (225) respectively.

[39] The input gear (220) and the first intermediate gear (240a) are the primary gears. The output gear (225) and the second intermediate gear (240b) are the secondary gears. In one example, the primary gear ratio is 3.08 and the secondary gear ratio is 2.53 and the overall gear ratio is 3.08 x 2.53, i.e., equal to 7.8. Consider for example the electric motor (205) torque is 26 Nm, then the output torque is 26 Nm x 7.8, i.e., 202.8 Nm.

[40] The input gear (220), the output gear (225), the first intermediate gear (240a) and the second intermediate gear (240b) are helical gears. Figure 2B and Figure 2F illustrate a perspective view of the helical gears in the powertrain (200), according to an embodiment of the present disclosure. Helical gears have the advantage of being less noisy compared to spur gears. Moreover, helical gears transfers more force and can be arranged more compactly in the gearbox unit (265).

[41] Further referring to Figure 2B, it is to be noted that the support bearing (215) is disposed proximate and co-planar to the output gear (225). Also, the output gear (225) is positioned at a predetermined distance from the rear wheel (235). This is to provide space for accommodating a brake lever (255) and minimize lateral offset of the motor (205) from the rear wheel (235). The space provided for accommodating the brake lever (255) enables easier serviceability of the brake lever (255). The brake lever (255) is illustrated in Figure 2E and Figure 2F. Further, positioning of the output gear (225) away from the rear wheel (235) improves center of gravity of the saddle-type vehicle (10).

[42] A first axis (A) extends from a center point of the intermediate shaft (250) and a center point of the input shaft (210) and is inclined at a predetermined angle (?) with reference to a second axis (B) extending between the center point of the intermediate shaft (250) and a center point of the output shaft (230), such that an oil seal (260) and the support bearing (215) are disposed offset from a periphery of the output gear (225). The predetermined angle (?) forming between the first axis (A) and the second axis (B) is illustrated in Figure 2C. In one example, by adjusting the angle (?) of the shafts, as much as 32 mm of offset space is provided by which the brake lever (255) can be easily accommodated and removed for serviceability.

[43] In one embodiment, the saddle-type vehicle (10) includes the chassis and the rear wheel (235). The saddle-type vehicle (10) includes the powertrain (200) which drives the saddle-type vehicle (10). The powertrain (200) is coupled to the rear wheel (235). The powertrain (200) includes a motor (205), an input shaft (210) coupled to the motor (205), a support bearing (215) coupled to the input shaft (210) and an input gear (220) coupled to the input shaft (210). The powertrain (200) includes an output gear (225) coupled to an output shaft (230). The support bearing (215) is disposed proximate and co-planar to the output gear (225). Further, the powertrain (200) of the saddle-type vehicle (10) includes a first intermediate gear (240a) and a second intermediate gear (240b). The first and second intermediate gears (240a, 240b) are coupled to an intermediate shaft (250). The first intermediate gear (240a) and the second intermediate gear (240b) are engaged to the input gear (220) and the output gear (225) respectively. In the powertrain (200), a first axis (A) extending between a center point of the intermediate shaft (250) and a center point of the input shaft (210) is inclined at a predetermined angle (?) with reference to a second axis (B) extending between the center point of the intermediate shaft (250) and a center point of the output shaft (230), such that an oil seal (260) and the support bearing (215) are disposed offset from a periphery of the output gear (225). Further, the output gear (225) is positioned at a predetermined distance from a rear wheel (235) to provide space for accommodating a brake lever (255) and minimize lateral offset of the motor (205) from the rear wheel (235).

[44] Figure 2D illustrates a perspective view of the gearbox unit (265), according to an embodiment of the present disclosure. The gearbox unit (265) includes the primary gears, i.e., the input gear (220) and the first intermediate gear (240a). The gearbox unit (265) includes the secondary gears, i.e., the output gear (225) and the second intermediate gear (240b). The primary gears and the secondary gears are positioned in a two-stage gear layout. Further, the gearbox unit (265) is able to easily accommodate the oil seal (260) and the support bearing (215) on the shafts.

[45] The gearbox unit (265) provides various advantages. The current gearbox architecture and layout is designed to accommodate the brake drum (not shown) on one side and the electric motor (205) on the other side while keeping the CG close to the vehicle centerline. The positioning of the output gear (225) away from wheel (235) and accommodating the primary drive (primary gears) in that region along with the positioning of the bearing (215) co-planar with the output gear (225) gives an improvement of 20% in the lateral CG. This improvement is when compared to the arrangement where the primary gears are positioned closer to the motor (205) rather than the rear wheel (235). This arrangement also gives space for the brake lever (255) and improves lateral offset of the motor (205).

[46] In this application, unless specifically stated otherwise, the use of the singular 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.

[47] List of reference numerals:
Components Reference numerals
Powertrain 200
Saddle-type vehicle 10
Motor 205
Input shaft 210
Support bearing 215
Input gear 220
Output gear 225
Output shaft 230
First intermediate gear 240a
Second intermediate gear 240b
Intermediate shaft 250
First axis A
Second axis B
Angle ?
Rear wheel 235
Brake lever 255
Oil seal 260
Gearbox unit 265
, Claims:1. A powertrain (200) for a saddle-type vehicle (10), the powertrain (200) comprising:
a motor (205);
an input shaft (210) coupled to the motor (205);
a support bearing (215) coupled to the input shaft (210);
an input gear (220) coupled to the input shaft (210);
an output gear (225) coupled to an output shaft (230), wherein the support bearing (215) is disposed proximate and co-planar to the output gear (225); and
a first intermediate gear (240a) and a second intermediate gear (240b), wherein the first and second intermediate gears (240a, 240b) are coupled to an intermediate shaft (250), wherein the first intermediate gear (240a) and the second intermediate gear (240b) are engaged to the input gear (220) and the output gear (225) respectively.

2. The powertrain (200) as claimed in claim 1, wherein a first axis (A) extending between a center point of the intermediate shaft (250) and a center point of the input shaft (210) is inclined at a predetermined angle (?) with reference to a second axis (B) extending between the center point of the intermediate shaft (250) and a center point of the output shaft (230), such that an oil seal (260) and the support bearing (215) are disposed offset from a periphery of the output gear (225).

3. The powertrain (200) as claimed in claim 1, wherein the output gear (225) is positioned at a predetermined distance from a rear wheel (235) to provide space for accommodating a brake lever (255) and minimize lateral offset of the motor (205) from the rear wheel (235).

4. The powertrain (200) as claimed in claim 3, wherein the space provided for accommodating the brake lever (255) enables easier serviceability of the brake lever (255).
5. The powertrain (200) as claimed in claim 3, wherein the output gear (225) is positioned at a predetermined distance from the rear wheel (235) to improve a center of gravity of the saddle-type vehicle (10).

6. The powertrain (200) as claimed in claim 1, wherein the output shaft (230) is configured to drive a rear wheel (235).

7. The powertrain (200) as claimed in claim 1, wherein the input gear (220), the output gear (225), the first intermediate gear (240a), and the second intermediate gear (240b) are helical gears.

8. A saddle-type vehicle (10), the saddle-type vehicle (10) comprising:
a rear wheel (235);
a powertrain (200) coupled to the rear wheel (235), the powertrain (200) comprising:
a motor (205);
an input shaft (210) coupled to the motor (205);
a support bearing (215) coupled to the input shaft (210);
an input gear (220) coupled to the input shaft (210);
an output gear (225) coupled to an output shaft (230), wherein the support bearing (215) is disposed proximate and co-planar to the output gear (225); and
a first intermediate gear (240a) and a second intermediate gear (240b), wherein the first and second intermediate gears (240a, 240b) are coupled to an intermediate shaft (250), wherein the first intermediate gear (240a) and the second intermediate gear (240b) are engaged to the input gear (220) and the output gear (225) respectively.

9. The saddle-type vehicle (10) as claimed in claim 8, wherein a first axis (A) extending between a center point of the intermediate shaft (250) and a center point of the input shaft (210) is inclined at a predetermined angle (?) with reference to a second axis (B) extending between the center point of the intermediate shaft (250) and a center point of the output shaft (230), such that an oil seal (260) and the support bearing (215) are disposed offset from a periphery of the output gear (225).

10. The saddle-type vehicle (10) as claimed in claim 8, wherein the output gear (225) is positioned at a predetermined distance from a rear wheel (235) to provide space for accommodating a brake lever (255) and minimize lateral offset of the motor (205) from the rear wheel (235).