Description:FIELD OF THE INVENTION
[001] The present invention relates to a saddle type vehicle. More particularly, the present invention relates to provision of a transmission assembly in a saddle type vehicle.

BACKGROUND OF THE INVENTION
[002] Conventional saddle type vehicles, particularly conventional electric saddle type vehicles have a traction motor either directly attached to the wheel hub or connected to the rear wheel by means of a transmission system. Generally, when the traction motor is not directly mounted on the hub of the wheel, the traction motors rotate very high speeds of up to 12,000 RPM. However, if such high speed of rotation is directly transferred to the rear wheel, the same will result in toppling of the vehicle. Thus, for effective working, a reduction of rotation speed is required for transmission of power from the traction motor to the rear wheel.
[003] For achieving this reduction, generally a two-step transmission is utilised wherein a gear is connected to the shaft of the traction motor, and this gear is connected to another larger gear by means of belt drive. However, such two- step transmission can only be employed in scooter type electric vehicle because the two-step transmission requires a large packaging space for accommodation, and the available packaging space in a scooter type vehicle is relatively larger. However, in a motorcycle type electric vehicle, particularly motorcycles having a single naked frame, the traction motor cannot be mounted on the hub of the rear wheel, and needs to be accommodated within the constrained motorcycle layout. A further challenge in motorcycle type vehicles is that the disposition of the high-power battery and the traction motor significantly alter the centre of gravity of the vehicle due to ineffective weight distribution.
[004] Additionally, in order to transfer the power from the traction motor to the wheels of the vehicle in the motorcycle layout, a swing arm and a transmission system is provided which includes a multi-stage gear reduction assembly. Further in conventional vehicles, the multi-stage gear reduction transmission system includes separate housings to host the individual gears. This in turn increases the weight of the vehicle and even further alters the centre of gravity of the vehicle. Furthermore, multi-stage gear reduction system requires multiple belts in between each pair of gears. Prolonged use of the multiple belts results in loosening of the belts, which in turn reduces the effective transfer of power from the motor assembly to the rear wheel.
[005] Thus, there is a need in the art for a saddle type vehicle which addresses the aforementioned problems.

SUMMARY OF THE INVENTION
[006] In an aspect, the present invention is directed towards a saddle type vehicle. The vehicle has a traction motor being configured to provide traction force for the saddle type vehicle, and a traction motor housing, wherein the traction motor is provided in the traction motor housing. A transmission housing is integrated with the traction motor housing. The transmission housing extends outwardly from the traction motor housing in the vehicle width direction. Further, the vehicle has a transmission assembly. The transmission assembly has a first drive gear and a first driven gear. The first drive gear is connected to a drive shaft of the traction motor, and the first driven gear is configured to be operatively connected to the first drive gear. Herein, the first drive gear and the first driven gear of the transmission assembly are housed in the transmission housing.
[007] In an embodiment of the invention, the saddle type vehicle has a frame assembly extending in a vehicle front-rear direction, wherein traction motor housing is configured to be supported on the frame assembly.
[008] In another embodiment of the invention, the saddle type vehicle has a swing arm being swingably attached to the frame assembly, and is configured to support a rear wheel of the saddle type vehicle.
[009] In a further embodiment of the invention, the traction motor housing is disposed forwardly of the swing arm in the vehicle front-rear direction.
[010] In a further embodiment of the invention, the saddle type vehicle has one or more batteries for supplying power to the traction motor. The one or more batteries are supported on the frame assembly, wherein the traction motor housing is disposed rearwardly of the one or more batteries in the vehicle front-rear direction.
[011] In a further embodiment of the invention, the first driven gear is configured to be meshed with the first drive gear.
[012] In a further embodiment of the invention, the transmission assembly has a first driven shaft. The first driven shaft is connected to the first driven gear and protrudes outwardly from the first driven gear in the vehicle width direction.
[013] In a further embodiment of the invention, the transmission assembly has a second drive gear and the second drive gear is mounted on the first driven shaft.
[014] In a further embodiment of the invention, the transmission assembly has a driven pulley. The driven pulley is configured to be connected to a hub of a rear wheel of the vehicle for driving the rear wheel, and the driven pulley is operatively coupled to the second drive gear by means of a belt drive.
[015] In a further embodiment of the invention, the saddle type vehicle has a cover member. The cover member is configured to cover the transmission housing, thereby forming an enclosed space between the cover member and the transmission housing for enclosing the first drive gear and the first driven gear.
[016] In a further embodiment of the invention, the transmission housing has a substantially pyriform shape having a first end and a second end, wherein a diameter of the first end is smaller than a diameter of the second end.
[017] In a further embodiment of the invention, the transmission housing has a first gear receiver provided at the first end of the transmission housing and the first gear receiver is configured to receive the first drive gear.
[018] In a further embodiment of the invention, the transmission housing has a second gear receiver provided at the second end of the transmission housing, and the second gear receiver is configured to receive the first driven gear.

BRIEF DESCRIPTION OF THE DRAWINGS
[019] 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 illustrates a left side view of a saddle type vehicle, in accordance with an embodiment of the invention.
Figure 2 illustrates a perspective view of the saddle type vehicle, in accordance with an embodiment of the invention.
Figure 3A and 3B illustrate perspective view of a transmission assembly of the saddle type vehicle, in accordance with an embodiment of the invention.
Figure 4 illustrates an exploded view of the transmission assembly of the saddle type vehicle, in accordance with an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION
[020] The present invention relates to a saddle type vehicle. More particularly, the present invention relates to provision of a transmission assembly in a saddle type vehicle. Herein, the vehicle includes a power unit that comprises an electric drive source.
[021] Figure 1 illustrates a left side view of a saddle type vehicle 10 in accordance with an embodiment of the invention. As illustrated, the saddle type vehicle 10 has a frame assembly 20. The frame assembly 20 extends in a front-rear direction of the vehicle 10. The frame assembly 20 comprises a head pipe 22, and a main frame 24 extending rearwardly and downwardly of the head pipe 22. Further, the vehicle 10 has a swing arm 34. The swing arm 34 is swingably attached to the frame assembly 20. Particularly, the swing arm 34 is swingably attached to the main frame 24 and longitudinally extends rearwardly from the main frame 24. The swing arm 34 is provided to swingably support a rear wheel (not shown) of the saddle type vehicle 10.
[022] As illustrated in Figure 1 and Figure 2, the saddle type vehicle 10 comprises a traction motor (not shown). The traction motor is configured to provide traction force for the saddle type vehicle 10. To supply power to the traction motor, a suitable power source is provided. In an embodiment, the saddle type vehicle 10 comprises one or more batteries 12 for supplying power to the traction motor. The one or more batteries 12 are supported on the frame assembly 20. More particularly, the one or more batteries 12 are supported on the main frame 24. In an embodiment, the one or more batteries 12 comprises a pair of batteries with each battery supported on the main frame 24. One battery is disposed on a left side of the main frame 24 and the other battery is disposed on a right side of the main frame 24 in a vehicle width direction.
[023] As illustrated in Figure 1 and Figure 2, the saddle type vehicle 10 comprises a traction motor housing 110. The traction motor is provided in the traction motor housing 110. The traction motor housing 110 extends in the vehicle width direction. In an embodiment, the traction motor housing 110 is supported on the frame assembly 20 of the saddle type vehicle 10. In that, the traction motor housing 110 is disposed forwardly of the swing arm 34 in the vehicle front-rear direction. Further, the traction motor housing 110 is disposed rearwardly of the one or more batteries 12 in the vehicle front-rear direction, thus allowing for the traction motor and the one or more batteries 12 to be accommodated in the limited packaging space available in the saddle type vehicle 10. The traction motor housing 110 with the traction motor being provided rearwardly of the one or more batteries 12 and forwardly of the swing arm 34 also ensures that the traction motor is accommodated without significantly altering the centre of gravity of the vehicle 10.
[024] Further, the saddle type vehicle 10 comprises a transmission housing 120, wherein the transmission housing 120 is integrated with the traction motor housing 110. As illustrated in Figure 2, the transmission housing 120 extends outwardly from the traction motor housing 110 in the vehicle width direction. Thus effectively, a single integrated housing having the traction motor housing 110 and the transmission housing 120 extending outwardly from the traction motor housing 110 is provided. In an embodiment, the transmission housing 120 integrates with the traction motor housing 110 at an interface surface 120I (shown in Figure 4).
[025] As further illustrated in Figure 3A, Figure 3B and Figure 4, the saddle type vehicle 10 comprises a transmission assembly 130. The transmission assembly 130 has a first drive gear 132 and a first driven gear 134. Herein, the first drive gear 132 is connected to a drive shaft 112 of the traction motor, and rotates with the drive shaft 112 of the traction motor. Further, the first driven gear 134 is configured to be operatively connected to the first drive gear 132. As illustrated, the first drive gear 132 and the first driven gear 134 of the transmission assembly 130 are housed in the transmission housing 120. Thus, the first drive gear 132 and the first driven gear 134 are provided in the single transmission housing 120. Further, the traction motor, the first drive gear 132 and the first driven gear 134 are housed in the single integrated housing having the traction motor housing 110 and the transmission housing 120. As a result of this, the requirement of provision of different housings for different gears is eliminated.
[026] In an embodiment, the first drive gear 132 and the first driven gear 134 are spur gears and the first driven gear 134 is configured to mesh with the first drive gear 132. In this embodiment, the first driven gear 134 has a higher number of gear teeth and has a larger diameter than the first drive gear 132, and thus the speed of rotation of the first driven gear 134 is lower than the first drive gear 132. Accordingly, the high rotation speed of the drive shaft 112 of the traction motor is transmitted to the first driven gear 134 which rotates at a reduced speed, thus achieving speed reduction, before the power is transmitted to the rear wheel of the saddle type vehicle 10.
[027] In an embodiment, as specifically illustrated in Figure 3B, the transmission housing 120 has a substantially pyriform shape, also known as pear shape. The pyriform shape of the transmission housing has a first end 120A and a second end 120B. Herein, a diameter of the first end 120A is smaller than a diameter of the second end 120B. This allows the transmission housing to adequately house the smaller first drive gear 132 at the first end 120A, and the larger first driven gear 134 at the second end 120B, while ensuring that the transmission housing 120 remains compact.
[028] As illustrated in Figure 4, the transmission housing 120 comprises a first gear receiver 124 provided at the first end 120A of the transmission housing 120 and the first gear receiver 124 is configured to receive the first drive gear 132. Similarly, the transmission housing 120 comprises a second gear receiver 126 provided at the second end 120B of the transmission housing 120 and the second gear receiver 126 being configured to receive the first driven gear 134. Herein, the first gear receiver 124 and the second gear receiver 126 are provisions integrated in the transmission housing 120. The integrated provisions of the first gear receiver 124 and the second gear receiver 126 thus eliminate the requirement of separate housings and separate mounting brackets for the mounting or receiving the first drive gear 132 and the first driven gear 134. Further, the saddle type vehicle 10 has a cover member 122. The cover member 122 is configured to cover the transmission housing 120. Thus, the provision of the cover member 122 forms an enclosed space between the cover member 122 and the transmission housing 120 for enclosing the first drive gear 132 and the first driven gear 134. Provision of a single cover member 122 for the single transmission housing 120 further eliminates the requirement of multiple cover members for multiple gear housings.
[029] Further, in an embodiment, as illustrated in Figure 3A, Figure 3B and Figure 4, for further transmission of power from the first driven gear 134 further to the rear wheel, the saddle type vehicle 10 comprises a first driven shaft 136. The first driven shaft 136 is connected to the first driven gear 134 and protruding outwardly from the first driven gear 134 in the vehicle width direction. Thus, the first driven shaft 136 rotates with the first driven gear 134. Further, the transmission assembly 130 comprises a second drive gear 142 and the second drive gear 142 is mounted on the first driven shaft 136. Thus, the second drive gear 142 rotates along with the first driven gear 134 and the first driven shaft 136.
[030] Further, the transmission assembly 130 comprises a driven pulley 144. The driven pulley 144 is configured to be connected to a hub of a rear wheel of the vehicle 10 for driving the rear wheel. The driven pulley 144 is operatively coupled to the second drive gear 142 by means of a belt drive 146. In one embodiment, the driven pulley 144 is operatively coupled to the second drive gear 142 by means of a chain drive. The driven pulley 144 has a larger diameter than the second drive gear 142, and thus rotational speed is reduced during transmission from the second drive gear 142 to the driven pulley 144. Thus, in effect, a first stage speed reduction in the transmission assembly 130 occurs between the first drive gear 132 and the first driven gear 134, and a second stage speed reduction in the transmission assembly 130 occurs between the second drive gear 142 and the driven pulley 144, thereby achieving required speed reduction from the traction motor to the rear wheel.
[031] Advantageously, the present invention provides a saddle type vehicle wherein a transmission assembly for two stage speed reduction from the traction motor to the rear wheel is accommodated in a compact vehicle layout.
[032] Further, the present invention provides an integrated housing integrating the traction motor housing and the transmission housing, wherein the transmission housing houses the first drive gear and the first driven gear. Thus, a requirement of multiple housings or individual housings to be provided for each gear is eliminated, which results in lower part count, lower weight, and reduced complexity and cost. The reduced part count also allows for better serviceability and easier maintenance.
[033] Furthermore, the provision of the traction motor housing, and thus the traction motor forwardly of the swing arm and the rearwardly of the one or more batteries ensures that the traction motor and the transmission assembly are packaged close to centre of the vehicle in both lengthwise and width-wise senses, thus maintaining the centre of gravity of the vehicle.
[034] In addition, the present invention also eliminates the requirement of multiple belts in the transmission assembly, as the first drive gear meshes with the first driven gear and the second drive gear is provided on the second drive shaft connected to the first driven gear. Thus, only a single belt drive is used for connecting the second drive gear to the driven pulley. The elimination of requirement of multiple belts ensures that there are no multiple belts that can loosen up and reduce the efficiency of the power transmission from the traction motor to the rear wheel.
[035] 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
10: Saddle type vehicle
12: One or more batteries
20: Frame Assembly
22: Head Pipe
24: Main Frame
34: Swing Arm
110: Traction Motor Housing
112: Drive Shaft
120: Transmission Housing
120A: First End of Transmission Housing
120B: Second End of Transmission Housing
122: Cover Member
124: First Gear Receiver
126: Second Gear Receiver
130: Transmission Assembly
132: First Drive Gear
134: First Driven Gear
136: First Driven Shaft
142: Second Drive Gear
144: Driven Pulley
146: Belt Drive

, Claims:1. A saddle type vehicle (10), comprising:
a traction motor, the traction motor being configured to provide traction force for the saddle type vehicle (10);
a traction motor housing (110), the traction motor being provided in the traction motor housing (110);
a transmission housing (120), the transmission housing (120) being integrated with the traction motor housing (110), and the transmission housing (120) extending outwardly from the traction motor housing (110) in the vehicle width direction; and
a transmission assembly (130), the transmission assembly (130) having a first drive gear (132) and a first driven gear (134), the first drive gear (132) being connected to a drive shaft (112) of the traction motor, and the first driven gear (134) being configured to be operatively connected to the first drive gear (132), wherein the first drive gear (132) and the first driven gear (134) of the transmission assembly (130) are housed in the transmission housing (120).

2. The saddle type vehicle (10) as claimed in claim 1, comprising a frame assembly (20) extending in a vehicle front-rear direction, wherein traction motor housing (110) being configured to be supported on the frame assembly (20).

3. The saddle type vehicle (10) as claimed in claim 2, comprising a swing arm (34), the swing arm (34) being swingably attached to the frame assembly (20), and being configured to support a rear wheel of the saddle type vehicle (10).

4. The saddle type vehicle (10) as claimed in claim 3, wherein the traction motor housing (110) being disposed forwardly of the swing arm (34) in the vehicle front-rear direction.

5. The saddle type vehicle (10) as claimed in claim 2, comprising one or more batteries (12) for supplying power to the traction motor, the one or more batteries (12) being supported on the frame assembly (20), wherein the traction motor housing (110) being disposed rearwardly of the one or more batteries (12) in the vehicle front-rear direction.

6. The saddle type vehicle (10) as claimed in claim 1, wherein the first driven gear (134) being configured to be meshed with the first drive gear (132).

7. The saddle type vehicle (10) as claimed in claim 1, wherein the transmission assembly (130) comprises a first driven shaft (136), the first driven shaft (136) being connected to the first driven gear (134) and protruding outwardly from the first driven gear (134) in the vehicle width direction.

8. The saddle type vehicle (10) as claimed in claim 7, wherein the transmission assembly (130) comprises a second drive gear (142), the second drive gear (142) being mounted on the first driven shaft (136).

9. The saddle type vehicle (10) as claimed in claim 8, wherein the transmission assembly (130) comprises a driven pulley (144), the driven pulley (144) being configured to be connected to a hub of a rear wheel of the vehicle (10) for driving the rear wheel, and the driven pulley (144) being operatively coupled to the second drive gear (142) by means of a belt drive (146).

10. The saddle type vehicle (10) as claimed in claim 1, composing a cover member (122), the cover member (122) being configured to cover the transmission housing (120), thereby forming an enclosed space between the cover member (122) and the transmission housing (120) for enclosing the first drive gear (132) and the first driven gear (134).

11. The saddle type vehicle (10) as claimed in claim 1, wherein the transmission housing (120) has a substantially pyriform shape having a first end (120A) and a second end (120B), wherein a diameter of the first end (120A) is smaller than a diameter of the second end (120B).

12. The saddle type vehicle (10) as claimed in claim 11, wherein the transmission housing (120) comprises a first gear receiver (124) provided at the first end (120A) of the transmission housing (120), the first gear receiver (124) being configured to receive the first drive gear (132).

13. The saddle type vehicle (10) as claimed in claim 11, wherein the transmission housing (120) comprises a second gear receiver (126) provided at the second end (120B) of the transmission housing (120), the second gear receiver (126) being configured to receive the first driven gear (134).