Claims:We claim:

1. A speed sensor assembly (400) for measuring a speed of a rotating device of a vehicle (100) , said speed sensor assembly (403) comprising:
a sensing unit (403);
wherein, said sensing unit (403) having a
a cover (406);
wherein, said cover (406) being integrally assembled with said sensing unit (403);
characterized in that,

said cover having a mounting surface (404) disposed in an orthogonal direction of said sensing unit (403);
wherein, said mounting surface (404) being adapted for mounting said speed sensor assembly (400) on to said rotating device;
wherein, said mounting surface (404) having a projecting wall (402),
wherein, said projecting wall (402) being projected towards a direction of said sensing unit (403) and being disposed along a periphery of said mounting surface (404).
2. The speed sensor assembly (400) as claimed in claim 1, wherein a continuous groove (405) being formed between said projecting wall (402) of said mounting surface (404) and said cover (406);
wherein, said groove (405) enables said speed sensor assembly (400) to be abuttingly mounted on the rotating device.
3. The speed sensor assembly (400) as claimed in claim 1, wherein said rotating device being a gear box (204) having one or more gears (205,206,207);
wherein, said gear box (204) being configured with a sealing means (501) to adaptively get secured inside the groove (405) for forming a contamination free joint at the interface.
4. The speed sensor assembly (400) as claimed in claim 1, wherein said projecting wall (402) being parallel to a length direction of said sensing unit (403).
5. The speed sensor assembly (400) as claimed in claim 1, wherein said mounting surface (404) being configured with a opening (601) on the mounting surface (404) to enable mounting and securing of said speed sensor assembly (400) on said rotating device.
6. The speed sensor assembly (400) as claimed in claim 1, wherein said vehicle (100) being a straddle type vehicle.
, Description:TECHNICAL FIELD
[0001] The present subject matter generally relates to a saddle type vehicle. More particularly but not exclusively the present subject matter relates to a vehicle speed sensor mounting structure for said saddle type vehicle.
BACKGROUND
[0002] Vehicle speed sensors are broadly classified into two categories i.e. active speed sensors and passive speed sensors, which are implemented in a vehicle. The active speed sensors require power to operate whereas the passive speed sensor creates an AC (Alternate Current) signal that changes frequency with the speed of the wheel and signal is being provided as long as the wheel is in a moving condition. There are several methods to measure the speed of the vehicle using technique based on image, radar, GPS (Global Positioning System), magnetic sensor etc.
BRIEF DESCRIPTION OF THE DRAWINGS
[0003] Figure 1 illustrates a side view of the exemplary two-wheeled vehicle, in accordance with an embodiment of the present subject matter.
[0004] Figure 2 illustrates a side perspective view of the crank case assembly, in accordance with an embodiment of the present subject matter.
[0005] Figure 3 illustrates a prior art wherein a speed sensor is mounted on the gear box without any provision to seal the gap, in accordance with an embodiment of the present subject matter.
[0006] Figure 4 illustrates a cross sectional view of the present invention,
[0007] Figure 5illustratesa cross sectional view of the speed sensor assembly on a crank case assembly, in accordance with an embodiment of the present subject matter.
[0008] Figure 6 illustrates a perspective view of the speed sensor assembly, in accordance with an embodiment of the present subject matter.

DETAILED DESCRIPTION
[0009] Speed sensor has become a essential requirement in a vehicle wherein the vehicle is equipped with a digital speedometer. The vehicle speed sensor is not only used for measuring the speed of the vehicle but for several other functions such as Idle stop start function, which depends on the speed of the vehicle.
[00010] Generally, the speed sensor is mounted on the gear box crank case assembly and the speed sensor senses the tooth of the reduction gear which is used to find the speed of the vehicle. The speed sensor is commonly provided on a bracket which keeps the sensor at a fixed location and this also makes the wire routing convenient. But the location of the speed sensor is such that the speed sensor is exposed to foreign matter such as mud or dust which can adversely affect the functioning of the speed sensor and eventually the speed sensor may also stop working. The speed sensor is mounted on the gear box of the crank case assembly with a gasket provided in between the speed sensor and the gear crank case. The gasket is a mechanical seal, which fills the space created between the speed sensor and the gear box of the crankcase assembly. But providing an extra element such as a gasket increases the overall cost and also increase the time of assembly.
[00011] Hence, it is the object of the present subject matter to provide a speed sensor assembly which enables the speed sensor to be protected from any foreign material like dust and water without adding any additional component.
[00012] Another aspect of the present subject matter is to provide a speed sensor assembly which comprises a sensing unit. As per an aspect of present invention, the sensing unit is operated by a stator with a central permanent magnet and a soft iron core surrounded by an induction winding. The stator is positioned so that the sensing unit has a clearance or air gap between the stator pole and a tooth of a reduction gear. As the reduction gear rotates, the air gap between the sensing unit and the tooth of the reduction gear charges, which lead to change in the magnetic field from the permanent magnet within the sensing unit. The magnetic flux induces current in the stator circuit. The magnetic flux generated and the value of the induced current depends on the rotation speed of the gear reduction.
[00013] Yet another aspect of the present subject matter is to provide a speed sensor assembly, wherein the sensing unit comprises a cover. As per an embodiment, the cover of the sensing unit is integrally assembled with the sensing unit. As per an additional embodiment, the cover of the sensing unit is made up of non-conductive material such as resin. The cover of the sensing unit keeps the sensing unit protected from any external impact and eliminates any damage from the water or grease.
[00014] Still another aspect of the present subject matter is to provide a speed sensor assembly in which the cover has a mounting surface, which is disposed in an orthogonal direction with respect to the sensing unit. The mounting surface is adaptively mounted on a rotating device such as the crankcase assembly.
[00015] Yet another aspect of the present subject matter is to provide a speed sensor assembly in which the mounting surface of the cover of the sensing unit has a projecting wall. The projecting wall is projected in a direction towards the sensing unit and the projecting wall is disposed along a periphery of the mounting surface. The projecting wall is parallel to the sensing unit.
[00016] Fig. 1 illustrates a left side view of an exemplary two-wheeled vehicle (100), in accordance with an embodiment of the present subject matter. The vehicle (100) can be a straddle type vehicle. The vehicle (100) illustrated, has a schematically shown frame assembly (105) (shown in dotted line). In the present embodiment, the frame assembly(105) is step-through type includes a head tube (105A), and a main frame (105B) that extend rearwardly downward from an anterior portion of the head tube (105A). The main frame (105B) extends inclinedly rearward to a rear portion of the vehicle (100).
[00017] The vehicle (100) includes one or more prime movers that are connected to the frame assembly (105). In the present implementation, one of the prime movers is an IC engine (115) mounted to the frame assembly (105). In the depicted embodiment, the IC engine (115) is mounted to a structural member (135) that is pivoted to the frame assembly (105). In one embodiment, the structural member (135) is a rigid member made of metal. The vehicle (100) also includes another prime mover, which is an electric motor (120). In a preferred embodiment, the electric motor (120) is hub mounted to one wheel of the vehicle (100). In another embodiment, more than one electric motor is mounted to wheels of the vehicle. In the depicted embodiment, the vehicle (100) includes at least two-wheels and the electric motor (120) is hub mounted to the rear wheel (125) of the vehicle. A front wheel (110) is rotatably supported by the frame assembly(105) and is connected to a handle bar assembly (130) that enables manoeuvring of the vehicle (100).
[00018] Further, the vehicle (100) includes a high-capacity on-board battery (not shown) that drives the electric motor (120). The high-capacity battery may include one or more high-capacity battery packs or one or more low-capacity cells. The high-capacity battery can be disposed at a front portion, a rear portion, or at the centre of the vehicle (100). The high-capacity battery is supported by the frame assembly (105) and the vehicle (100) includes plurality of body panels, mounted to the frame assembly (105) for covering various components of the vehicle (100). The plurality of panels includes a front panel (140A), a leg shield (140B), an under-seat cover (140C), and a left and a right-side panel (140D). A glove box may be mounted to a leg shield (140B).
[00019] A floorboard (145) is provided at the step-through portion defined by the main frame (105B). A seat assembly (150) is disposed rearward to the step-through portion and is mounted to the main frame (105B). The seat assembly (150) that is elongated in a longitudinal direction F-R of the vehicle (100) enables the user to operate the vehicle in a straddle ride-type posture. One or more suspension(s) connect the wheels (110), (125) to the vehicle (100) and provide comfortable ride. The vehicle (100) comprises of plurality of electrical and electronic components including a headlamp unit (155A) movably supported on a head tube (105A), a taillight (155B), a starter motor (not shown), a horn etc. Also, the vehicle (100) includes a master control unit (not shown) that takes control of the overall operation of the vehicle (100) including the function of the IC engine (115), the electric motor (120), charging of the batteries from a magneto/integrated starter generator (ISG), driving of loads by the magneto/ISG, charging of the high capacity batteries by the electric motor operating in generator mode, and any other operations associated with the operation of the vehicle (100).the vehicle (100) can be a two-wheeled saddle type or a three wheeled vehicle
[00020] Fig. 2 depicts a side view of a IC engine with a crankcase (200) of a crankcase assembly (220) of the vehicle (100). The crankcase (200) is removably attached to cylinder block (201). A cylinder head (202) is fastened to a cylinder head cover (203). The cylinder head (202) is removably attached to a cylinder block (201). A throttle body (203), for controlling air intake, is coupled to the cylinder head (202). The crank case (200) is capable of accommodating a crankshaft (not shown); a continuous variable transmission system (not shown) comprising a drive pulley (not shown) and a driven pulley (not shown). The drive pulley and said driven pulley are supported on the crankcase (200). A gear box (204) encasing a first gear (205) to engage with a first intermediate gear (206); the first intermediate gear (206) is enmeshed with a third gear (207). The third gear (207) supported on a rear wheel axle (208). A speed sensor assembly (400) is mounted on the gear box (204). The gear box (204) encases the reduction gear assembly (205,206,207) and the speed sensor detects / senses the rotation of the first gear (205) thereby determining the rotation of the rear wheel axle (208).The speed sensor assembly (400) has a sensing unit (403) (refer fig. 4) to sense said rotation of said first gear (205).
[00021] Fig. 3 illustrates a side perspective view of the crank case assembly (220).
[00022] Fig. 4 illustrates a prior art wherein a speed sensor (300) is mounted on the gear box (204) with a gap created between the gear box (204) and the speed sensor (300). This gap G leads to seepage of water and direct entry.
[00023] Fig. 5 illustrates a cross sectional view of the speed sensor assembly (400). The speed sensor assembly (400) comprises a sensing unit (403) to sense the motion of gear teeth (210) of the first gear unit (205). The sensing unit (403) has a cover (406) which encapsulates the sensing unit (403) along a length of the sensing unit (403). The length of the sensing unit (403) being along a direction of insertion of the sensor assembly (400) on to the crankcase (200). The cover (406) is integrally assembled with the sensing unit (403) to protect the sensing unit (403) from any mechanical impact or malfunction caused by any external material like water or oil-based material like grease. The cover (406) has a mounting surface (404) disposed in an orthogonal direction with respect to the sensing unit (403). A mounting surface (404) is provided on the speed sensor assembly (400). The mounting surface (404) enables mounting the speed sensor assembly (400) on a surface of the gearbox closer to the rotating device such as a reduction gear assembly (204,205,206) of a crankcase assembly (220). The mounting surface (404) has a projecting wall (402). The projecting wall (402) is projected in a direction towards the sensing unit (403). The projecting wall (402) is disposed along a periphery of the mounting surface (404). The projecting wall (402) is oriented parallel to the length direction of the sensing unit (403).
[00024] A continuous groove (405) is formed between the projecting wall (402) of the mounting surface (404) and the cover (406). This groove (405) enables the speed sensor assembly to be abuttingly mounted on a rotating device such as the gears inside the gear box (204) of the crankcase assembly (220), having one or more gear arrangement. A wire cable (not shown) is routed from the speed sensor assembly (400) to a vehicle control unit (not shown) through a wire routing means (401).
[00025] Fig. 6 illustrates a cross sectional view of the present invention in which the speed sensor assembly (400) is mounted on the gear box (204) of the crank case assembly (220). The gear box (204) is configured with a projection wall (501) orthogonal to an external surface of the gear box (204). The projection wall (501) so formed creates a cavity (502) therein to receive the speed sensor assembly (400) and said projection wall (501) acts like a sealing means. The sensing unit (403) of the speed sensor assembly (400) is secured inside the cavity (502) formed on the gear box (204) outer surface. This cavity (502) enables the sensing unit (403) to remain in close proximity to the gear teeth (210). The sensing unit (403) senses the motion of the gear teeth (210).
[00026] Further, the gear box (204) having the sealing means (501), has one of its end portion being adaptively secured inside the groove (405) thereby resulting in a contamination free joint at the interface in an assembled condition. This locking of the sealing means (501) into the continuous groove (405) prevents any leakage of water or entry of fine dust particle into the sensing unit (403). Also, this design eliminates the requirement of any additional component such as a gasket. The sealing means (501) forms the part of the gear box (204).
[00027] Fig. 7 illustrates a perspective view of the speed sensor assembly (400) as per an additional embodiment. As per this embodiment, the speed sensor assembly (400) is provided with an opening (601) on the mounting surface (404). for mounting and securing the speed sensor assembly (400) on the gear box (204) The speed sensor assembly (400) is mounted on the outer surface of the gear box (204) through suitable means like a fastener (not labelled). The mounting of the speed sensor assembly (400) via the opening (601) keeps the speed sensor assembly (400) at a fixed place and eliminates the adverse effects of vibration on the speed sensor assembly (400) during the riding condition of the vehicle (100).

LIST OF REFERENCE SIGNS

vehicle (100)
frame assembly (105)
head tube (105A)
main frame (105B)
internal combustion (IC) engine (115)
structural member (135)
electric motor (120)
rear wheel (125)
front wheel (110)
handle bar assembly (130)
front panel (140A)
leg shield (140B)
right-side panel (140D)
floorboard (145)
headlamp unit (155A)
head tube (105A)
a taillight (155B)
crankcase (200)
cylinder block (201)
cylinder head (202)
throttle body (203)
gear box (204)
first gear (205)
first intermediate gear (206)
third gear (207)
speed sensor assembly (400)
a sensing unit (403)
gear teeth (210)
cover (406)
mounting surface (404)
crankcase assembly (220)
projecting wall (402)
groove (405)
wire routing means (401)
cavity (502)
sealing means (501)
mounting point (601)