Claims:We claim:
1. An assembly (100) of an auxiliary actuator (110) to assist a mechanically actuated Continuously Variable Transmission (CVT), said CVT comprising a driving pulley (103) and a driven pulley connected to each other with a belt (108), each of said pulleys comprises one fixed sheave (102) and a movable sheave (104), said driving pulley (103) is coupled to a crankshaft of an engine, and said driven pulley is coupled to wheels of said vehicle, said auxiliary actuator (110) is a motor which assists said CVT, characterized by:
a connecting pin (118) coupled to said movable sheave (104) of said driving pulley (103), said connecting pin (118) comprising a tapered end protruding out of said driving pulley (103), and
at least one mechanical linkage coupling said auxiliary actuator (110) to said tapered end of said connecting pin (118), said auxiliary actuator (110) is operatively activated to move said connecting pin (118) in a linear direction and thereby adjust width between said fixed sheave (102) and said movable sheave (104) of said driving pulley (103).

2. The assembly (100) as claimed in claim 1, wherein said auxiliary actuator (110) is at least one selected from a group comprising a linear actuator, electromagnetic actuator, pneumatic actuator, and a hydraulic actuator.

3. The assembly (100) as claimed in claim 1, wherein said mechanical linkage is at least one selected from a group comprising a Bowden cable, a clutch cable, a support shaft (120), a rod and a lever (112).

4. The assembly (100) as claimed in claim 1, wherein said mechanical linkage comprises a pivoted lever (112), a first end of which is connected to said auxiliary actuator (110) and a second end is connected to a cable (116), said cable (116) is connected to a support shaft (120), said support shaft (120) is in turn coupled to said tapered end of said connecting pin (118).

5. The assembly (100) as claimed in claim 4, wherein said support shaft (120) is rotatable on longitudinal axis, and said rotary motion of said support shaft (120) is transformed to linear motion of said connecting pin (118).

6. The assembly (100) as claimed in claim 1, wherein said mechanical linkage comprises a cable (116) connecting said auxiliary actuator (110) to a support shaft (120), and said support shaft (120) coupled to tapered end of said connecting pin (118).

7. The assembly (100) as claimed in claim 1, wherein said mechanical linkage comprises a cable (116) connecting said auxiliary actuator (110) to said tapered end of said connecting pin (118).

8. The assembly (100) as claimed in claim 1, wherein movement of said connecting pin (118) is held at a position when a desired speed ratio of said CVT is achieved by controlling said auxiliary actuator (110), while said auxiliary actuator (110) assists said mechanically actuated CVT.

9. The assembly (100) as claimed in claim 1, wherein said mechanically actuated CVT brings said connecting pin (118) back to original position when said auxiliary actuator (110) is deactivated.

10. The assembly (100) as claimed in claim 9, wherein said linear motion comprises a first pull motion imparted by said auxiliary actuator (110) and a second pull motion opposite to said first pull motion imparted by said mechanically actuated CVT. , Description:Field of the invention:
[0001] The present disclosure relates to an assembly of an auxiliary actuator for a mechanically actuated Continuously Variable Transmission (CVT), and particularly relates to the mechanism of assisting the CVT.

Background of the invention:
[0002] According to a patent US5662538, a device for adjusting pitch diameter of sheave of variable speed mechanism is provided. The patent discloses a device for adjusting the sheave pitch diameter of a variable speed mechanism which includes an output shaft, a linking member, an upper urging rod, a lower urging rod, and a motor. The device can be operated easily and safely such that the speed changing information is quantified and displayed.

Brief description of the accompanying drawings:
[0003] An embodiment of the disclosure is described with reference to the following accompanying drawings,
[0004] Fig. 1 illustrates a top view of an auxiliary actuator assembly, according to an embodiment of the present invention;
[0005] Fig. 2 illustrates a coupling between the connecting pin and the support shaft, according to an embodiment of the present invention;
[0006] Fig. 3 illustrates a side view of the assembly of the auxiliary actuator, according to an embodiment of the present invention, and
[0007] Fig. 4 illustrates a method executed by an Electronic Control Unit (ECU) to assist the mechanically actuated CVT, according to an embodiment of the present invention.

Detailed description of the embodiments:
[0008] Fig. 1 illustrates a top view of an auxiliary actuator assembly, according to an embodiment of the present invention. An assembly 100 of the auxiliary actuator 110 to assist a mechanically actuated Continuously Variable Transmission (CVT) is provided. The mechanically actuated CVT comprises a variator 106 comprising plurality of roller weights. The CVT comprises a primary pulley/driving pulley 103 and a secondary pulley/driven pulley (not shown) connected to each other with a belt 108, each of the pulleys comprises one fixed sheave 102 and a movable sheave 104. The driving pulley 103 is coupled to crankshaft of an engine of a vehicle, and the driven pulley is coupled to the wheels of the vehicle through a reduction unit. The auxiliary actuator 110 is a motor which assists the CVT as known in the art. The assembly 100 is characterized by, a connecting pin 118 coupled to the movable sheave 104 of the driving pulley 103. The connecting pin 118 comprises a tapered end protruding out of the driving pulley 103. Further, at least one mechanical linkage coupling the auxiliary actuator 110 to the tapered end of the connecting pin 118 is provided. The auxiliary actuator 110 is operatively activated/controlled to move the connecting pin 118 in linear direction and thereby adjust width between the fixed sheave 102 and the movable sheave 104 of the driving pulley 103.

[0009] The auxiliary actuator 110 is at least one selected from a group comprising, a linear actuator/ motor, electromagnetic actuator, pneumatic actuator, a hydraulic actuator and the like. The auxiliary actuator 110 comprises a moving part which moves (rotation or linear motion) due to the type of actuator and respective actuating force used. The mechanical linkage is connected or coupled to the moving part of the auxiliary actuator 110.

[0010] The mechanical linkage is at least one selected from a group comprising a cable 116 such as a Bowden cable and a clutch cable, a support shaft 120, a rod, a lever 112 and the like.

[0011] In accordance to an embodiment of the present invention, the mechanical linkage comprises a pivoted lever 112, a first end of which is connected to the auxiliary actuator 110 and a second end of which is connected to the cable 116. The cable 116 is passed through an optional guide 114 and connected to the support shaft 120, the support shaft 120 is in turn coupled to the tapered end of the connecting pin 118.

[0012] A working method for assisting the mechanically actuated CVT is provided. Based on the movement/ rotation of the lever 112 by the auxiliary actuator 110, the cable 116 is moved thereby moving the support shaft 120 and the connecting pin 118.

[0013] The support shaft 120 is rotatable on longitudinal axis, and the rotary motion of the support shaft 120 is transformed to linear motion of the connecting pin 118. The linear motion corresponds to the axial movement of the connecting pin 118 due to pull or push force. Alternatively, the linear motion of the connecting pin 118 signifies displacement in positive and negative direction. The limit of the rotation and/or the linear motion (back and forth) is decided based on requirement and is configurable.

[0014] In accordance to another embodiment of the present invention, the mechanical linkage comprises a cable 116 connecting the auxiliary actuator 110 to the support shaft 120, and the support shaft 120 is coupled to the tapered end of the connecting pin 118.

[0015] In accordance to yet another embodiment of the present invention, the mechanical linkage comprises a cable 116 connecting the auxiliary actuator 110 directly to the tapered end of the connecting pin 118.

[0016] The mechanically actuated CVT brings/ restores the connecting pin 118 back to original position after the auxiliary actuator 110 is deactivated. When the accelerator of the vehicle is released, the auxiliary actuator 110 is switched OFF. The roller weights or flyweights inside the movable sheave 104 of the driving pulley 103 under the spring force, moves to resting/default position and thereby restores the connecting pin 118 to original position. The connecting pin 118 is then ready for the next assistance by the auxiliary actuator 110 when required.

[0017] The linear movement/motion of the connecting pin 118 comprises a first pull motion imparted by the auxiliary actuator 110 and a second pull motion opposite to the first pull motion is imparted by the mechanically actuated CVT.

[0018] Fig. 2 illustrates a coupling between the connecting pin and the support shaft, according to an embodiment of the present invention. A connecting pin-shaft coupling 202 is shown by the dashed circle. The tapered end of the connecting pin 118 comprises a neck portion with reduced radius towards the end. The connecting pin 118 ends with a broad end. The support shaft 120 is provided with a specific groove. The groove or cut-out part of the support shaft 120 is locked with the tapered end of the connecting pin 118. The opposite end of the connecting pin 118 is connected to the movable sheave 104 through a housing 122. The housing 122 rests on a connection sleeve over the bearings. The connection sleeve is threaded to the bush. The movable sheave 104 is fit to a bush which extends through the fixed sheave 102. The bush is coupled with the housing 118 through the connection sleeve.

[0019] Fig. 3 illustrates a side view of the assembly of the auxiliary actuator, according to an embodiment of the present invention. The auxiliary actuator 110 is shown to be coupled to the cable 116 through a pivoted lever 112. The cable 116 connects the auxiliary actuator 110 to the support shaft 120. The cable 116 is supported by a first spring 306 and a second spring 304 on both ends to compensate the slackness. The profile of the groove at the end of the support shaft 120 is shown, which locks and engages with the connecting pin 118 to move the movable sheave 104 in back and forth motion to provide assistance while changing the speed ratio.

[0020] With reference to Fig. 3 and in accordance to an embodiment of the present invention, an Electronic Control Unit (ECU) 300 to control an auxiliary actuator 110 is provided. The auxiliary actuator 110 assists the mechanically actuated Continuously Variable Transmission (CVT), the ECU 300 comprising components such as but not limited to a processor, I/O ports, a memory unit, an ADC/DAC converter and all of which interconnected with buses. The ECU 300 is configured to receive inputs 302 comprising engine speed, vehicle speed and throttle position from respective sensor. The ECU 300 then access a map from the memory element and reads a desired (CVT ratio) based on the inputs 302. The ECU 300 then computes an actual CVT Ratio from the inputs 302 and compares with the desired CVT ratio to determine an offset CVT ratio. The desired CVT ratio is derived from the map. The ECU 300 then sends control signal to operate the auxiliary actuator 110 and assists the CVT by achieving the desired CVT ratio based on the offset CVT ratio. The ECU 300 is the Engine Control Unit or a dedicated controller in communication with the Engine Control Unit.

[0021] Fig. 4 illustrates a method executed by an Electronic Control Unit (ECU) to assist the mechanically actuated CVT, according to an embodiment of the present disclosure. The method comprises a step 402 comprising receiving inputs 302 comprising engine speed, vehicle speed and throttle position from respective sensor continuously or periodically. The ECU 300 optionally detects shaft displacement by a position sensor. The position sensor senses position of the displaced auxiliary actuator’s 110 shaft/ moving part. A step 404 comprises checking/ deciding based on the inputs 302, whether the actual speed ratio/ CVT ratio is equal to the desired speed ratio. The speed ratio is calculated by dividing engine speed to the vehicle speed. If the decision is true, then the step 406 is executed, which comprises the ECU 300 controlling the auxiliary actuator 110 in such a manner that the speed ratio is held at the desired speed ratio. At the end of the step 406, the ECU 300 executes from the step 402 again. This refers to self-locking mechanism. The locking mechanism locks the displaced shaft in determined position. If the decision at step 404 is false, then the ECU 300 executes the step 408 comprising moving the actual speed ratio to desired speed ratio by controlling the auxiliary actuator 110.

[0022] Once the ECU 300 assists through the auxiliary actuator 110, the ECU 300 as per the step 410, again decides whether the actual CVT ratio is greater than the desired CVT ratio. If decision is false at the step 410, the ECU 300 executes the step 412 which comprises controlling the auxiliary actuator 110 to achieve a lower CVT ratio (example 2.3), followed by repeating the steps from step 402 onwards. If the decision at the step 410 is true, then the ECU 300 executes the step 414, which comprises controlling the auxiliary actuator 110 to achieve a higher CVT ratio (example 0.8) followed by repeating the steps from the step 402 onwards.

[0023] In accordance to an embodiment of the present disclosure, utilization of cable 116 is done for the actuation of the CVT. In particular, a Bowden cable is used to connect the driving pulley 103 of the CVT to the auxiliary actuator 110 with the help of new mechanical linkage. The assembly 100 of the auxiliary actuator 110 reduces the limitation of actuators, specifically electromechanical actuators mounted along the crankshaft which adds axial load and is subjected to high vibration and heat from the engine when compared to the standard acceptable limit. The assembly 100, increases/ improves the durability and functionality of the auxiliary actuator 110. The assembly 100 along with the auxiliary actuator 110 is isolated from the source of vibration and heat by the placement away from the crank shaft axis or the engine. The assembly 100 provides easy, simple and good serviceability and replacement of internal components.

[0024] 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.