THEREOF

CROSS REFERENCE TO RELATED APPLICATION

This application is based on and derives the benefit of Indian Provisional Application 202041009140 filed on 03 ^rd March 2020, the contents of which are incorporated herein by reference.

TECHNICAL FIELD

[001] The embodiments herein relate to a centrifugal clutch assembly for use in applications such as automotive and industrial machine.

BACKGROUND

[002] A forced air induction system of an engine is used to provide compressed air to the engine to produce more power thereby increasing the efficiency and performance of the engine. Some forced air induction systems of the engine uses a supercharger which is an air compressor driven by the engine to provide compressed air to the engine. Superchargers are mechanically driven by the engine and impart a mechanical load on the engine. Other forced air induction systems of the engine uses a turbocharger which is driven by exhaust gases from the engine. Though, turbocharger does not impart a direct mechanical load on the engine, turbochargers is subjected to exhaust back pressure on engines thereby increasing pumping losses. Turbo lag occurs because turbochargers rely on the buildup of exhaust gas pressure to drive a turbine of the turbocharger. The exhaust gas pressure of the engine at idle, low engine speeds, or low throttle is usually insufficient to drive the turbine of the turbocharger. Only when the engine reaches sufficient speed, the turbine spins fast enough to rotate the turbocharger compressor to provide compressed air with intake pressure above atmospheric pressure. Therefore, the turbocharger is effective at higher speeds of the engine whereas the supercharger is effective at lower speeds of the engine. Most superchargers include an integral step up gearbox to increase the speed of the air compressor to achieve optimal compressor efficiency. The step up gearbox is complex in design and expensive. In most cases, the supercharger gearbox is a fixed high ratio gearbox and the supercharger is required to be disengaged from the engine to reduce the traction load of driving the supercharger when the engine is operating at higher speeds. Hence, engines are provided with both the supercharger and the turbocharger. In such twin charged engines, a centrifugal clutch is used to engage the supercharger with the engine when the crankshaft of the engine is rotating at the lower speed. The centrifugal clutch disengages the supercharger from the engine and the turbocharger provides compressed air to the engine when the crankshaft is rotating at higher speeds.

[003] The centrifugal clutch is used to transmit the motion and torque of mechanical rotary power from the engine to the supercharger by engaging a driven section of the centrifugal clutch with a driving section of the centrifugal clutch by virtue of action by the centrifugal forces generated in the centrifugal clutch. The centrifugal clutch includes flyweights which move radially outwards to engage with a drum connecting the driven section with the driving section of the centrifugal clutch. The speed at which the engagement is desired is predetermined which in turn defines the mass of the flyweights and the springs to ensure such engagements. However, the centrifugal clutch once engaged at a predetermined rotational speed cannot be there after disengaged at a higher rotational speed than the rotational speed at which it was engaged prior. Therefore, the rotational speed of the driving section of the centrifugal clutch was reduced to disengage the driven section from the driving section of the centrifugal clutch.

[004] Hence, there is no freedom of disengaging the driven section from the driving section of the centrifugal clutch when either or both motion and torque/ power transmission is undesired at the driven section of the centrifugal clutch, whereas at the same time either reducing or holding the rotational speed of the driving section of the centrifugal clutch is not possible and rise of rotational speed at input end is required for the performance of the engine.

[005] Therefore, there exists a need for a centrifugal clutch assembly, which obviates the aforementioned drawbacks.

OBJECTS

[006] The principal object of an embodiment herein is to provide a centrifugal clutch assembly for use in applications such as automotive and industrial machines.

[007] Another object of an embodiment herein is to provide a method of operation of a centrifugal clutch assembly.

[008] Another object of an embodiment is to provide a centrifugal clutch assembly in a supercharger of an engine. [009] Another object of an embodiment herein is to provide a centrifugal clutch assembly for automatic engagement and disengagement of a supercharger when the engine is operated at a lower speed and a higher speed respectively.

[0010] Another object of an embodiment herein is to provide a centrifugal clutch assembly for use in a twin charged engine.

[0011] Another object of an embodiment herein is to provide a dual action centrifugal clutch assembly, where one action of the centrifugal clutch assembly being engaging a driving section with a driven section of the centrifugal clutch assembly when the driving section is at a first predetermined rotational speed and there after second action of the centrifugal clutch assembly being disengaging of the driven section from the driving section of the centrifugal clutch assembly when the driving section of the centrifugal clutch assembly is at a second predetermined rotational speed that being higher rotational speed as compared to the rotational speed at which the driven section was engaged earlier.

[0012] Another object of an embodiment herein is to provide a centrifugal clutch assembly, which enables automatic disengagement of a driven section of the centrifugal clutch assembly from a driving section of the centrifugal clutch assembly when the driving section of the centrifugal clutch assembly is at a higher rotational speed. Alternately, the same objective can also be achieved through adapting “freewheel clutch mechanism /one way clutch / overrunning clutch mechanism” in place of driven section of centrifugal clutch assembly.

[0013] Another object of an embodiment herein is to provide a centrifugal clutch assembly, which is reliable and enables precise operability.

[0014] Another object of an embodiment herein is to provide a centrifugal clutch assembly, which reduces undesired energy losses.

[0015] Another object of an embodiment herein is to provide a compact and light weight centrifugal clutch assembly, which is easy to install and is inexpensive.

[0016] These and other objects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications. BRIEF DESCRIPTION OF DRAWINGS

[0017] The embodiments of the invention are illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in the various figures. The embodiments herein will be better understood from the following description with reference to the drawings, in which:

[0018] Fig. 1 depicts a front view of a centrifugal clutch assembly, according to embodiments as disclosed herein;

[0019] Fig. 2 depicts a cross sectional view of the centrifugal clutch assembly along the section line A-A of fig. 1, according to embodiments as disclosed herein;

[0020] Fig. 3 depicts a cross sectional view of the centrifugal clutch assembly along the section line C-C of fig. 2, according to embodiments as disclosed herein;

[0021] Fig. 4 depicts a cross sectional view of the centrifugal clutch assembly along the section line B-B of fig. 2, where the centrifugal clutch assembly is in an engaged position, according to embodiments as disclosed herein;

[0022] Fig. 5 depicts a cross sectional view of the centrifugal clutch assembly along the section line B-B of fig. 2, where the centrifugal clutch assembly is in a disengaged position, according to embodiments as disclosed herein;

[0023] Fig. 6 depicts a schematic diagram of the centrifugal clutch assembly being used in a twin charged engine, according to embodiments as disclosed herein; and

[0024] Fig. 7 depicts a flowchart indicating a method of operation of the centrifugal clutch assembly, according to another embodiment as disclosed herein.

DETAILED DESCRIPTION

[0025] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.

[0026] The embodiments herein achieve a centrifugal clutch assembly for use in applications such as automotive and industrial machine. Further, embodiments herein achieve a centrifugal clutch assembly for automatic engagement and disengagement of a supercharger with respect to an engine when the engine is operated at a lower speed and a higher speed respectively. Referring now to the drawings, and more particularly to Figs. 1 through 7, where similar reference characters denote corresponding features consistently throughout the figures, there are shown embodiments.

[0027] Fig. 2 depicts a cross sectional view of the centrifugal clutch assembly (100) along the section line A-A of fig. 1, according to embodiments as disclosed herein. Fig. 3 depicts a cross sectional view of the centrifugal clutch assembly (100) along the section line C-C of fig. 2, according to embodiments as disclosed herein. In an embodiment, the centrifugal clutch assembly (100), as shown in fig. 1 to fig. 6) includes an input member (102), a plurality of bearings (103A, 103B), a rotatable member (104), a support member (105), a plurality of first engaging members (106), a plurality of first resilient members (108), a plurality of first retention members (110), a driven member (112), a plurality of second engaging members (114), a plurality of second resilient members (116), a plurality of second retention members (118) and an output member (120). For the purpose of this description and ease of understanding, the centrifugal clutch assembly (100) is explained herein below with reference to automatic engagement and disengagement of a supercharger (10S), as shown in fig. 6) with respect to an engine (10), as shown in fig. 6) when the engine (10) is operated at a lower speed and a higher speed respectively. However, it is also within the scope of the invention to provide the centrifugal clutch (100) for automatic engagement and disengagement of rotary members used in automotive, industrial machines, displacement fluid pumps, screw compressors, rotary blowers, other similar devices and any other applications without otherwise deterring the intended function of the centrifugal clutch assembly (100) as can be deduced from the description and corresponding drawings. The input member (102), the rotatable member (104), the plurality of first engaging members (106) and the plurality of first retention members (110) forms the driving section of the centrifugal clutch assembly (100). The driven member (112), the plurality of second engaging members (114), the plurality of second retention members (118) and the output member (120) forms the driven section of the centrifugal clutch assembly (100). The engine (10) includes but not limited to a crankshaft (IOC), a supercharger (10S), a turbocharger (10T) and a valve (10V). The supercharger (10S) is driven by the crankshaft (IOC) of the engine (10) through the centrifugal clutch assembly (100). The turbocharger (10T) is driven by exhaust gases from the engine (10). The supercharger (10S) is adapted to provide compressed air to the engine (10) when the crankshaft (IOC) is rotating at a lower speed. For example, the range of the lower speed of the engine is from 600 to 700 rpm. It is also within the scope of the invention to increase or decrease the range value for the lower speed of the engine based on the requirement, design and engine configuration. The turbocharger (10T) is adapted to provide compressed air to the engine when the crankshaft (IOC) is rotating at a higher speed. For example, the range of higher speed of the engine (10) is from 1900 to 2000 rpm. It is also within the scope of the invention to increase or decrease the range value for the higher speed of the engine based on the requirement, design and engine configuration. The valve (10V) is adapted to regulate the flow of compressed air from at least one of the supercharger (10S) and the turbocharger (10T) to the engine (10) based on the speed of the engine (10).

[0028] The input member (102) is driven by the crankshaft (IOC), as shown in fig. 6) of the engine (10). The input member (102) is rotatably connected to the crankshaft (IOC) by using any of belts, chains and any other linkages. For the purpose of this description and ease of understanding, the input member (102) is considered to be a pulley. The input member (102) is freely mounted onto the driven member (112) through the bearing (103B).The input member (102) drives the rotatable member (104). The rotatable member (104) is connected to the input member (102). The support member (105) is secured to the output member (120) by using a bolt. The support member (105) is adapted to support one end of the bearing (103A). The bearing (103A) is adapted to freely mount the driven member (112) onto the output member (120). The bearing (103B) is adapted to freely mount the input member (102) and the rotatable member (104) onto the driven member (112). The rotatable member (104), the plurality of first engaging members (106) and the plurality of first retention members (110) are freely rotating with respect to the output member (120). The rotatable member (104) is freely mounted onto the driven member (112) through the bearing (103B). The rotatable member (104) is driven by the input member (102). For the purpose of this description and ease of understanding, the rotatable member (104) is considered to be a rotatable hub. The rotatable member (104) is freely mounted on the output member (120) through the driven member (112) and the beatings (103A, 103B). The rotatable member (104) is adapted to hold and support the plurality of first engaging members (106). Each first engaging member (106) is positioned diametrically opposite to the other first engaging member (106) on the rotatable member (104). Each first engaging member (106) is located between the rotatable member (104) and corresponding first retention member (110). The plurality of first engaging members (106) are movably engaged with the rotatable member (104). For the purpose of this description and ease of understanding, each first engaging member (106) is considered to be a flyweight. The plurality of first retention members (110) and the plurality of first resilient members (108) are adapted to retain the plurality of first engaging members (106) on the rotational member (104) at a predetermined position. For the purpose of this description and ease of understanding, each first retention member (110) is considered to be a liner and each resilient member (108) is considered to be a spring. The first retention members (110) are located between the first engaging members (106) and the driven member (112). The plurality of first retention members (110) is selectively at least one of engaged and disengaged with respect to the driven member (112) based on the speed of the input member (102) corresponding to the speed of crankshaft (IOC) of the engine (10). Each first retention member (110) is engaged with an outer portion of corresponding each first engaging member (106). One end of each first resilient member (108) is connected to corresponding first retention member (110) and another end of the first resilient member (108) is connected to corresponding another first retention member (110).

[0029] The driven member (112) is freely rotating with respect to the output member (120). For the purpose of this description and ease of understanding, the driven member (112) is considered to be a drum. The driven member (112) is freely mounted onto the output member (120) through the bearing (103 A). The driven member (112) is adapted to house the plurality of first retention members (110), the plurality of first resilient members (108) and the plurality of first engaging members (106) at an input side of the driven member (112). The driven member (112) is adapted to house the plurality of second retention members (118), the plurality of second resilient members (116) and the plurality of second engaging members (114) at an output side of the driven member (112). The driven member (112) includes a common partition wall (112W), as shown in fig. 2) which is adapted to separate the plurality of first retention members (110) and the plurality of first engaging members (106) from the plurality of second retention members (118) and the plurality of second engaging members (114).

[0030] The plurality of second engaging members (114) is movably engaged with the driven member (112). Each second engaging member (114) is adapted to be engaged with corresponding each second retention member (118). For the purpose of this description and ease of understanding, each second engaging member (114) is considered to be a flyweight. Each second engaging member (114) is positioned diametrically opposite to other second engaging member (114) in the driven member (112). Each second engaging member (114) is located between the driven member (112) and corresponding second retention member (118). The plurality of second retention members (118) is adapted to be selectively at least one of engaged and disengaged with respect to the output member (120) based on the speed of the input member (102) corresponding to the speed of crankshaft (IOC) of the engine (10). Each second retention members (118) is adapted to be engaged with an inner portion of corresponding each second engaging member (114). For the purpose of this description and ease of understanding, each second retention member (118) is considered to be a liner and each second resilient member (116) is considered to be a spring. Each second retention member (118) is located between the output member (120) and corresponding second engaging member (114). The plurality of second resilient members (116) and the plurality of second retention members (118) are adapted to retain the plurality of second engaging members (114) in the driven member (112) at a predetermined position. One end of each second resilient member (116) is connected to corresponding second engaging members (114) and another end of the second resilient member (116) is connected to corresponding another second engaging member (114). The output member (120) is considered to be an output shaft which is coupled to an air compressor of the supercharger (10S).

[0031] The working of centrifugal clutch assembly (100) when the crankshaft (IOC) of the engine (10) is rotating at the lower speed is as follows. The input member (102) is driven by the crankshaft (IOC) of the engine (10) and the input member (102) in turn rotates the rotatable member (104), the plurality of first engaging members (106) and the plurality of first retention members (110). As the speed of the input member (102) reaches a first predetermined speed (SI) corresponding to the lower speed of the crankshaft (IOC) of the engine, the centrifugal force on the plurality of first engaging members (106) exceeds the tensile force of the plurality of first resilient members (108). Thus, the plurality of first engaging members (106) moves outwardly therein to move the plurality of first retention members (110) towards the driven member (112) thereby engaging the plurality of first retention members (110) with the driven member (112), as shown in fig. 3) to rotate the driven member (112). The driven member (112) in turn rotates the output member (120) through the plurality of second engaging members (114) and the plurality of second retention members (118). The rotational position of plurality of second engaging members (114) and the plurality of second retention members (118) being engaged to output member (120) is as shown in Fig 4. The output member (120) in turn drives the air compressor of the supercharger (10S) to provide compressed air to an air intake system of the engine (10) through the valve (10V).

[0032] The working of centrifugal clutch assembly (100) when the crankshaft (IOC) of the engine (10) is rotating at the higher speed is as follows. With increase in rotational speed of the input member (102) greater than the first predetermined speed (SI) of the input member (102), the plurality of first retention members (110) remains in engagement with the driven member (112) thereby driving the output member (120). As, the rotational speed of the input member (102) reaches a second predetermined speed (S2) corresponding to higher speed of the engine (10), the centrifugal force on the plurality of second engaging members (114) exceeds the tensile force of the plurality of second resilient members (116). Thus, the plurality of second engaging members (114) move outwardly therein to move the plurality of second retention members (118) away from the output member (120) thereby disengaging the plurality of second retention members (118) from the output member (120), as shown in fig. 5) to disengage the supercharger (10S) from the engine (10). When the crankshaft (IOC) of the engine (10) is rotating at such higher speed and when the centrifugal clutch assembly (100) disengages the supercharger (10S), the turbocharger (10T) provides compressed air to the air intake system of the engine (10) through the valve (10V).

[0033] When the rotational speed of the input member (102) is equal or less than the second predetermined speed (S2), the centrifugal forces on the plurality of second engaging members (114) reduces below the tensile forces of the plurality of the second resilient means (116). Thus, the plurality of second engaging members (114) moves inwardly therein to move the plurality of second retention members (118) towards the output member (120) thereby engaging the plurality of second retention members (118) with the output member (120) which in turn drives the air compressor of the supercharger (10S) to provide compressed air to an air intake system of the engine (10) through the valve (10V) when the crankshaft (IOC) of the engine (10) is rotating at the lower speed. [0034] When the rotational speed of the input member (102) is reduced below the first predetermined speed (SI), the centrifugal forces on the plurality of first engaging members (106) reduces below the tensile forces of the plurality of the first resilient means (108). Thus, the plurality of first engaging members (114) moves inwardly therein to move the plurality of first retention members (110) away from the driven member (112) to dis-engage the plurality of first retention members (110) from the driven member (112) thereby disengaging input member (102) from the output member (120).

[0035] In another embodiment, the driven section (driven member (112), second engaging members (114), second retention members (118), second resilient means (116) and output member (120)) of the centrifugal clutch assembly (100) can be replaced by a “freewheel clutch mechanism /one way clutch / overrunning clutch mechanism” to achieve the same result.

[0036] Fig. 7 depicts a flowchart indicating a method (200) of operation of the centrifugal clutch assembly (100), according to another embodiment as disclosed herein. For the purpose of this description and ease of understanding, the method (200) is explained herein below with reference to operation of the centrifugal clutch assembly (100) to automatic engagement and disengagement of the supercharger (10S) with respect to the engine (10) when the engine (10) is operated at a lower speed and a higher speed respectively. However, it is also within the scope of this invention to practice/implement the entire steps of the method (200) in a same manner or in a different manner or with omission of at least one step to the method (200) or with any addition of at least one step to the method (200) of operation of the centrifugal clutch assembly (100) for automatic engagement and disengagement of rotary members used in automotive, industrial machines, displacement fluid pumps, screw compressors, rotary blowers, other similar devices and any other applications without otherwise deterring the intended function of the method (200) as can be deduced from the description and corresponding drawings. At step 202, the method (200) includes driving, by an input member (102), a plurality of first retention members (110) through a rotatable member (104) and a plurality of first engaging members (106).

[0037] At step (204), the method (200) includes engaging the first retention members (110) with a driven member (112) in response to moving, by the first engaging members (106), the first retention members (110) towards the driven member (112) when the centrifugal force on the first engaging members (106) exceeds the tensile force of the first resilient members (108) on rotational speed of the input member (102) reaching a first predetermined speed (SI). [0038] At step (206), the method (200) includes driving, by, the driven member (112), an output shaft (120) through a plurality of second engaging members (114) and a plurality of second retention members (118) on engagement of the first retention members (110) with the driven member (112).

[0039] At step (208), the method (200) includes disengaging the second retention members (118) from the output member (120) in response to moving, by the second engaging members (114), the second retention members (118) away from the output member (120) when centrifugal force on the second engaging members (114) exceeds the tensile force of the second resilient members (116) on rotational speed of the input member (102) reaching a second predetermined speed (S2).

[0040] Further, the method (200) includes engaging the second retention members (118) with the output member (120) in response to moving, by the second engaging members (114), the second retention members (118) towards the output member (120) when centrifugal forces on the second engaging members (114) reduces below the tensile forces of the second resilient means (116) on the rotational speed of the input member (102) is equal or less than the second predetermined speed (S2).

[0041] Further, the method (200) includes dis-engaging the first retention members (110) from the driven member (112) thereby disengaging the input member (102) from the output member (120), in response to moving, by the first engaging members (114), the first retention members (110) away from the driven member (112) when the centrifugal forces on the first engaging members (106) reduces below the tensile forces of the first resilient means (108) on the rotational speed of the input member (102) is reduced below the first predetermined speed (SI).

[0042] The technical advantages of the centrifugal clutch assembly (100) are as follows. The centrifugal clutch assembly (100) is easy to install and is inexpensive. The centrifugal clutch assembly (100) reduces energy loss. The centrifugal clutch assembly (100) is reliable and enables precise operability.

[0043] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.