Claims:
1. A centrifugal clutch (100) comprising a housing (110), a clutch plate (120), a pressure plate (130), and a disengaging means; wherein the disengaging means is configured to disengage the pressure plate (130) and the clutch plate (120) above a predefined speed.
2. The centrifugal clutch as claimed in claim 1, wherein the housing (110), having frustoconical shape, comprises a conical surface (112), a small side (114) and a large side (116), wherein the housing (110) is configured to receive rotary motion from an input shaft (10) mounted on the small side (114) end of the housing (110).
3. The centrifugal clutch as claimed in claim 1, wherein the clutch plate (120) is configured to be securely mounted to the small side (114) of the housing to enable rotation of the clutch plate (120) along with the housing (110).
4. The centrifugal clutch as claimed in claim 1, wherein the pressure plate (130) and the clutch plate (120) are configured to be engaged below a predefined speed of the clutch plate (120) due to forces applied by the plurality of compression springs (140).
5. The centrifugal clutch as claimed in claim 1, wherein the disengaging means comprises plurality of compression springs (140) and at least one ball lever assembly (160) mounted on the pressure plate (130).
6. The centrifugal clutch as claimed in claim 1, wherein a groove with lining (117) embedded on the large side (116) of the housing is configured to rotatably mount a ring (150).
7. The centrifugal clutch as claimed in claim 6, wherein the groove with lining (117) is configured with a lining removably inserted in the groove.
8. The centrifugal clutch as claimed in claim 6 and 7, wherein the groove with lining (117) is configured with a material selected from a set of self-lubricating materials such as brass or brass-bronze and bearing material such as Chrome Steel, Stainless Steel, Ceramic, metal alloys and polymers.
9. The centrifugal clutch as claimed in claim 1, wherein first end (140a) of the plurality of compression springs (140) is configured to be secured and circumferentially mounted on the ring (150).
10. The centrifugal clutch as claimed in claim 1, wherein second end (140b) of the plurality of compression springs (140) is configured to be secured to mounting grooves (131) on the pressure plate (130) for establishing continuous contact with the clutch plate (120) and to provide rotary motion to an output shaft (20).
11. The centrifugal clutch as claimed in claim 1, wherein the ball lever assembly (160) is configured with:
an inner lever (162), wherein a first end (162a) of the inner lever is fixedly mounted to an outer edge of the pressure plate (130),
an outer lever (164), wherein a first end (164a) of the outer lever is hingedly mounted to a second end (162b) of the inner lever (162), and
a ball (166) rigidly mounted to a second end (164b) of the outer lever (164).
12. The centrifugal clutch as claimed in claim 1, wherein the ball (166) is configured to be a dead weight to provide centrifugal force for disengaging the pressure plate (130) and the clutch plate (120).
13. The centrifugal clutch as claimed in claim 1, wherein a hinge point (163) of the inner lever (162) and the outer lever (164) is configured to provide relative angular movement up to 180° between the inner lever (162) and the outer lever (164).
14. The centrifugal clutch as claimed in claim 1, wherein the ball lever assembly (160) is configured to expand due to increased centrifugal forces and the inclination on the conical surface (112) enables the ball lever assembly (160) to slide towards the large side (116) of the housing to disengage the pressure plate (130) from the clutch plate (120) by pressing the pressure plate (130) against the compression springs (140).
15. The centrifugal clutch as claimed in claim 1, wherein reduced centrifugal forces below the predefined speed are configured for regaining original position of the ball lever assembly (160) for enabling engagement of the pressure plate (130) with the clutch plate (120), due to the compression springs (140) force, for transferring rotary motion.
16. The centrifugal clutch as claimed in claim 1-12, wherein the input shaft (10) is configured to be mounted to a Dedicated Hybrid Transmission (DHT, 02) and the output shaft (20) is configured to be mounted to an electric motor (04); wherein the DHT (02) is configured to selectively receive rotary drive from a gasoline engine (06) and from the electric motor (04) and transfers to a drive axle (08) of a vehicle.
17. The centrifugal clutch as claimed in claim 13, wherein the centrifugal clutch (100) is configured to disengage the electric motor (04) from the DHT (02) above a predefined speed to prevent a reverse flow of the rotary drive from the DHT (02) to the electric motor (04).
18. A process for self-actuation of a centrifugal clutch (100) for disengaging and engaging, comprising the steps of:
receiving a rotary motion by a clutch plate (120) from an input shaft (10),
expanding a ball lever assembly (160) due to increased centrifugal forces above a predefined speed,
sliding the ball lever assembly (160) on a conical surface (112) towards a large side (116) of a housing (110) for pushing a pressure plate (130) against the forces of the compression springs (140) to disengage the pressure plate (130) from the clutch plate (120) to stop the transfer of rotary motion from the input shaft (10) to the output shaft (20),
contracting the ball lever assembly (160) due to reduction in centrifugal forces below the predefined speed, and
pushing the pressure plate (130) towards the clutch plate (120) by the compression springs (140) and engaging the pressure plate (130) with the clutch plate (120) to enable transfer of rotary motion from the input shaft (10) to the output shaft (20).
, Description:FORM 2

THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003

COMPLETE SPECIFICATION
(See Section 10 and Rule 13)

Title of invention:
A CENTRIFUGAL CLUTCH

Applicant:
Tata Motors Limited
A company Incorporated in India under the Companies Act, 1956
Having address:
Bombay House, 24 Homi Mody Street,
Hutatma Chowk, Mumbai 400001,
Maharashtra, India

The following specification particularly describes the invention and the manner in which it is to be performed.

FIELD OF THE INVENTION
[001] The present subject matter described herein generally relates to a centrifugal clutch, and more specifically to a centrifugal clutch configured to disengage above a predefined speed.
BACKGROUND
[002] A clutch is useful in devices that have two rotating shafts configured to connect conditionally. In a motor vehicle, one of the shafts is typically driven by a motor or an engine and other shaft drives a transmission/gearbox. The clutch connects the two shafts so that they can either be locked together and spin at the same speed, or be decoupled and spin at different speeds. In motor vehicles, the engine spins all the time, the wheels do not. Therefore, in order to stop the motor vehicle without shutting off the engine every time, the wheels need to be disconnected from the engine. The clutch allows for smooth engagement or disengagement of the spinning engine from the wheels or the vehicle transmission. This kind of application of the clutches is widely known in the art.
[003] The manual clutches are operated by a pedal to engage/disengage the drives and automatic clutches are operated automatically based on a predefined parameters meeting at a certain moment. The centrifugal clutch is a type of automatic clutch where on meeting a predetermined parameter the operation of the clutch is realized. A typical centrifugal clutch comprises a rotary part and one or more centrifugal masses enabling transfer of drive from one shaft to another on attaining a predefined speed. Below the predefined speed, the centrifugal clutch retains the disengaged configuration and prevents any drive transfer.
[004] Certain situations are realized where drive shaft and driven shaft are required to be disengaged above a certain speed limit. However, a traditional centrifugal clutch fails to meet the said purpose, as a typical configuration of the centrifugal clutch enables engagement of the shafts above a certain speed limit.
[005] The present subject matter discloses a novel centrifugal clutch to overcome the limitations stated above.
OBJECTS OF THE INVENTION
[006] One object of the present disclosure is to provide a centrifugal clutch for disengaging two shafts above a predefined speed.
[007] Another object of the present disclosure is to protect the electric motor and the battery against higher reverse thrust from the DHT at higher RPMs.
[008] Yet another object of the present disclosure is to provide a reverse centrifugal clutch which engages at lower RPMs and disengages above a predefined RPM.
SUMMARY
[009] Before the present system is described, it is to be understood that this application is not limited to the particular machine or device, as there can be multiple possible embodiments that are not expressly illustrated in the present disclosures. It is also to be understood that the terminology used in the description is for the purpose of describing the particular versions or embodiments only, and is not intended to limit the scope of the present application. This summary is provided to introduce aspects related to a centrifugal clutch, and the aspects are further elaborated below in the detailed description. This summary is not intended to identify essential features of the proposed subject matter nor is it intended for use in determining or limiting the scope of the proposed subject matter.
[0010] The present subject matter discloses a centrifugal clutch comprising a housing, a clutch plate, a pressure plate, and a disengaging means. The disengaging means comprises plurality of compression springs and a ball lever assembly. The disengaging means is configured to disengage the pressure plate and the clutch plate above a predefined speed. The pressure plate and the clutch plate are configured to be engaged below a predefined speed of the clutch plate due to forces applied by the plurality of compression springs.
[0011] In an embodiment, the centrifugal clutch is configured to disengage an electric motor shaft from a drive train shaft after attaining a pre-defined speed and again engages as the speed of the shaft decreases below the pre-defined level. Therefore, above a predefined speed, the centrifugal clutch is configured to prevent a reverse flow of the rotary drive from the Dedicated Hybrid Transmission (DHT) to the electric motor.
[0012] In an embodiment of the present subject matter, a process for self-actuation of a centrifugal clutch for disengaging and engaging is disclosed. The process comprises steps of: receiving a rotary motion by a clutch plate from an input shaft, expanding a ball lever assembly due to increased centrifugal forces above a predefined speed, sliding the ball lever assembly on a conical surface towards a large side of a housing for pushing a pressure plate against the forces of the compression springs to disengage the pressure plate from the clutch plate to stop the transfer of rotary motion from the input shaft to the output shaft, contracting the ball lever assembly due to reduction in centrifugal forces below the predefined speed, and pushing the pressure plate towards the clutch plate by the compression springs 140 and engaging the pressure plate with the clutch plate to enable transfer of rotary motion from the input shaft to the output shaft.
STATEMENT OF INVENTION
[0013] The present subject matter discloses a centrifugal clutch comprising a housing, a clutch plate, a pressure plate, and a disengaging means. The disengaging means is configured to disengage the pressure plate and the clutch plate above a predefined speed.
[0014] The housing, having frustoconical shape, comprises a conical surface, a small side and a large side, wherein the housing is configured to receive rotary motion from an input shaft mounted on the small side end of the housing. The clutch plate is configured to be securely mounted to the small side of the housing to enable rotation of the clutch plate along with the housing.
[0015] The pressure plate and the clutch plate are configured to be engaged below a predefined speed of the clutch plate due to forces applied by the plurality of compression springs. The disengaging means comprises a plurality of compression springs and at least one ball lever assembly mounted on the pressure plate.
[0016] A groove with lining embedded on the large side of the housing is configured to rotatably mount a ring. In an embodiment, the groove with lining 117 is configured with a lining removably inserted in the groove. The groove with lining 117 is configured with a material selected from a set of self-lubricating materials such as brass or brass-bronze and bearing material such as Chrome Steel, Stainless Steel, Ceramic, metal alloys and polymers. A first end of the plurality of compression springs is configured to be secured and circumferentially mounted on the ring. The second end of the plurality of compression springs are configured to be secured to mounting grooves on the pressure plate; for establishing continuous contact with the clutch plate and to provide rotary motion to an output shaft.
[0017] The ball lever assembly comprises an inner lever, an outer lever and a ball. A first end of the inner lever is fixedly mounted to an outer edge of the pressure plate. A first end of the outer lever is hingedly mounted to a second end of the inner lever. The ball fixedly mounted to a second end of the outer lever. The ball is configured to be a dead weight to provide centrifugal force for disengaging the pressure plate and the clutch plate.
[0018] A hinge point of the inner lever and the outer lever is configured to provide relative angular movement up to 180° between the inner lever and the outer lever.
[0019] The ball lever assembly is configured to expand due to increased centrifugal forces above the predefined speed and the inclination on the conical surface enables the ball lever assembly to slide towards the large side of the housing to disengage the pressure plate from the clutch plate by pressing the pressure plate against the compression springs. Further the reduced centrifugal forces below the predefined speed are configured for regaining original position of the ball lever assembly for enabling engagement of the pressure plate with the clutch plate, due to the compression springs force, for transferring rotary motion.
[0020] In an embodiment of the present subject matter, the input shaft is configured to be mounted to a Dedicated Hybrid Transmission DHT and the output shaft is configured to be mounted to an electric motor; wherein the DHT is configured to selectively receive rotary drive from a gasoline engine and from the electric motor and transfers to a drive axle of a vehicle. Therefore, the centrifugal clutch is configured to disengage the electric motor from the DHT above a predefined speed to prevent a reverse flow of the rotary drive from the DHT to the electric motor.
[0021] In an embodiment of the present subject matter, a process for self-actuation of a centrifugal clutch for disengaging and engaging is disclosed. The process comprises steps of: receiving a rotary motion by a clutch plate from an input shaft, expanding a ball lever assembly due to increased centrifugal forces above a predefined speed, sliding the ball lever assembly on a conical surface towards a large side of a housing for pushing a pressure plate against the forces of the compression springs to disengage the pressure plate from the clutch plate to stop the transfer of rotary motion from the input shaft to the output shaft, contracting the ball lever assembly due to reduction in centrifugal forces below the predefined speed, and pushing the pressure plate towards the clutch plate by the compression springs 140 and engaging the pressure plate with the clutch plate to enable transfer of rotary motion from the input shaft to the output shaft.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] The foregoing summary, as well as the following detailed description of embodiments, is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the disclosure, there is shown in the present document example constructions of the disclosure, however, the disclosure is not limited to the specific methods and device disclosed in the document and the drawing. The detailed description is described with reference to the following accompanying figures.
[0023] Figure 1 illustrates a centrifugal clutch in engaged configuration, in accordance with an embodiment of the present subject matter.
[0024] Figure 2 illustrates an exploded view of the centrifugal clutch, in accordance with an embodiment of the present subject matter.
[0025] Figure 3 illustrates a view of the pressure plate, in accordance with an embodiment of the present subject matter.
[0026] Figure 4 illustrates a view of the ball lever assembly, in accordance with an embodiment of the present subject matter.
[0027] Figure 5 illustrates the centrifugal clutch in disengaged configuration, in accordance with an embodiment of the present subject matter.
[0028] Figure 6 illustrates the centrifugal clutch configured between a dedicated hybrid transmission and an electric motor, in accordance with an embodiment of the present subject matter.
[0029] Figure 7 illustrates another view of the centrifugal clutch configured between the dedicated hybrid transmission and the electric motor, in accordance with an embodiment of the present subject matter.
[0030] The figures depict various embodiments of the present disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following discussion that alternative embodiments of the structures illustrated herein may be employed without departing from the principles of the disclosure described herein.
DETAILED DESCRIPTION
[0031] Some embodiments of this disclosure, illustrating all its features, will now be discussed in detail. The words "comprising", “having”, and "including," and other forms thereof, are intended to be equivalent in meaning and be open ended in that an item or items following any one of these words is not meant to be an exhaustive listing of such item or items, or meant to be limited to only the listed item or items. It must also be noted that as used herein and in the appended claims, the singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise. Although any devices and methods similar or equivalent to those described herein can be used in the practice or testing of embodiments of the present disclosure, the exemplary, devices and methods are now described. The disclosed embodiments are merely exemplary of the disclosure, which may be embodied in various forms.
[0032] Various modifications to the embodiment will be readily apparent to those skilled in the art and the generic principles herein may be applied to other embodiments. However, one of ordinary skill in the art will readily recognize that the present disclosure is not intended to be limited to the embodiments illustrated, but is to be accorded the widest scope consistent with the principles and features described herein.
[0033] Following is a list of elements and reference numerals used to explain various embodiments of the present subject matter.
Reference Numeral Element Description
02 Dedicated Hybrid Transmission (DHT)
03 Battery
04 Electric motor
06 Gasoline engine
08 Drive axle
10 Input shaft
20 Output shaft
100 Centrifugal clutch
110 Housing
112 Conical surface
114 Small side
116 Large side
117 Groove with lining
120 Clutch plate
130 Pressure plate
131 Mounting grooves for spring
140 Compression springs
140a First end of Compression spring
140b Second end of Compression spring
150 Ring
160 Ball lever assembly
162 Inner lever
164 Outer lever
166 Ball

[0034] A Clutch is an integral part of automotive transmission. Generally, a clutch is located in between engine and gearbox and helps to discontinue power flow from engine to gearbox to assist in gear shift and then again continues to supply engine torque to gearbox.
[0035] A centrifugal clutch is something which is used in automotive transmissions as well as in industrial transmissions for similar purpose where in there is a requirement for time bound engagement and disengagement. It generally engages at higher predetermined RPMs when the increasing centrifugal forces due to higher RPMs closes the clutch and transmits power/torque.
[0036] A Dedicated Hybrid Transmissions (DHT) comprises a gasoline/diesel engine and an electric motor to drive the transmission. The electric motor generally caters for 20-30% of total power requirement, rest being taken care by the engine. The electric motor is powered by a dedicated 48 V battery, and thus it becomes increasingly important to protect the electric motor and battery against higher reverse thrust from transmission gearbox either while coasting or while pure gasoline operation modes. The electric motor can operate safely till its Fly-Up RPM. Thus creating the need for protecting the electric motor, battery and its windings from higher RPMs and higher lateral and reverse thrust when the vehicle is operating at a higher speed. The Conventional Centrifugal Clutch works in a manner where it connects at higher speed/RPMs. So whenever the RPM reaches a pre-defined threshold value, the pressure plate pushes the clutch plate against the springs and engages the input and output shafts. Therefore, the Conventional Centrifugal Clutch cannot be used in DHT, since this type of clutch engages at high speeds and disengages at lower speeds, while in DHT, the electric motor and battery along with its windings need to be disengaged at higher speeds, thus a reverse mechanism is desired as compared to Conventional Centrifugal Clutch design.
[0037] The present subject matter discloses a centrifugal clutch configured to disengage the electric motor shaft from the drive train shaft after attaining a pre-defined speed and again engages as the speed of the shaft decreases below the pre-defined level.
[0038] Referring to Figure 1, a centrifugal clutch 100 is illustrated in accordance to an embodiment of the present subject matter. The clutch 100 is configured to transfer rotary drive from an input shaft 10 to an output shaft 20. The clutch 100 comprises a housing 110 having frustoconical shape, a clutch plate 120, a pressure plate 130, and a disengaging means. The housing 110 comprises a conical surface 112 and two side surfaces; a large side 116 and a small side 114, for closing the two ends of the conical surface. The housing 110 is configured to receive rotational drive from the input shaft 10 mounted on the small side 114 end of the housing 110, wherein the input shaft 10 and the small side 114 of the housing are having a splined interface. The clutch plate 120 is securely mounted to the small side 114 of the housing to enable rotation of the clutch plate 120 along with the housing 110. All the rotating parts are configured to rotate around a common axis connecting the input shaft 10 and the output shaft 20. The disengaging means comprises plurality of compression springs 140 and at least one ball lever assembly 160 mounted on the pressure plate 130.
[0039] Now referring to figures 2 and 3 disclosing an exploded view of the centrifugal clutch 100 and a view of the pressure plate 130 respectively in accordance to an embodiment of the present subject matter. The plurality of compression springs 140 comprises a first end 140a and a second end 140b. The first end 140a of the plurality of compression springs 140 is configured to be secured and circumferentially mounted on a ring 150, wherein the ring 140 is rotatably mounted in a groove with lining 117 on the large side 116 of the housing 110 and configured to rotate with respect to the housing 110. In an embodiment, the groove with lining 117 is configured with a lining removably inserted in the groove. The groove with lining 117 is configured with a soft material selected from a set of self-lubricating materials such as brass or brass-bronze and bearing material such as Chrome Steel, Stainless Steel, Ceramic, metal alloys and polymers. The second end 140b of the plurality of compression springs 140 is configured to be secured to the mounting grooves 131 on the pressure plate 130 and the plurality of compression springs 140 are provided to keep the pressure plate 130 in continuous contact with the clutch plate 120 below the predefined speed of the clutch plate 120 and provide rotary motion to an output shaft 20.
[0040] Now referring to figure 4 in accordance to an embodiment, the ball lever assembly 160 comprises an inner lever 162, an outer lever 164 and a ball 166. A first end 162a of the inner lever 162 is fixedly mounted to an outer edge of the pressure plate 130. The second end 162b of the inner lever is hingedly mounted to a first end 164a of the outer lever 164. The second end 164b of the outer lever 164 is fixedly mounted to the ball 166. In an embodiment, the ball 166 is configured to be a dead weight to provide centrifugal force for disengaging the pressure plate 130 and the clutch plate 120. In another embodiment, a hinge point 163 of the inner lever 162 and the outer lever 164 is configured to provide relative angular movement up to 180° between the inner lever 162 and the outer lever 164.
[0041] Referring to figures 1 and 5, during operation of the clutch 100, below a threshold speed limit, the pressure plate 130 and the clutch plate 120 remain in contact due to the compression springs 140 to enable transfer of the rotary motion from the input shaft 10 to the output shaft 20. The ball lever assembly 160 remains in a folded position until a predefined speed of rotation is achieved by the clutch plate 120. When the speed of the input shaft 10 and the clutch plate 120 reaches the predefined limit, the disengaging means is configured to disengage the pressure plate 130 and the clutch plate 120 and thereby stopping the transfer of rotary motion. The ball lever assembly 160 is configured to partially expand out due to centrifugal forces acting on it and the ball 166 gets in contact with the conical surface 112 of the housing 110. On reaching the threshold limit, the ball lever assembly 160 further expands due to increased centrifugal forces. Due to inclination on the conical surface 112, the ball lever assembly 160 slides towards the large side 116 of the housing and pushing the pressure plate 130 against the forces of the compression spring 140 and thereby enabling disengagement of the pressure plate 130 from the clutch plate 120. Once the pressure plate 130 and the clutch plate 120 are disengaged, the transfer of rotary motion from the input shaft 10 to the output shaft 20 is stopped. Therefore, the centrifugal clutch 100 of the present invention is configured to disengage above a predefined threshold speed as per the requirement of the system.
[0042] Referring to figure 1, once the speed of the pressure plate 130 falls below the threshold speed, the centrifugal force reduces and the ball lever assembly 160 starts contracting to regain its original position, causing movement of the pressure plate 130 towards the clutch plate 120 due to forces of the compression springs 140. The pressure plate 130 gets in contact with the clutch plate 120 and starts rotating at the same speed as that of the clutch plate 120. This normal operation of the centrifugal clutch 100 continues until the speed increases above the threshold limit again.
[0043] In an embodiment of the present subject matter, a process for self-actuation of a centrifugal clutch 100 for disengaging and engaging is disclosed. The process comprises steps of: receiving a rotary motion by a clutch plate 120 from an input shaft 10, expanding a ball lever assembly 160 due to increased centrifugal forces above a predefined speed, sliding the ball lever assembly 160 on a conical surface 112 towards a large side 116 of a housing 110 for pushing a pressure plate 130 against the forces of the compression springs 140 to disengage the pressure plate 130 from the clutch plate 120 to stop the transfer of rotary motion from the input shaft 10 to the output shaft 20, contracting the ball lever assembly 160 due to reduction in centrifugal forces below the predefined speed, and pushing the pressure plate 130 towards the clutch plate 120 by the compression springs 140 and engaging the pressure plate 130 with the clutch plate 120 to enable transfer of rotary motion from the input shaft 10 to the output shaft 20.
[0044] Referring to figure 6 and figure 7, the centrifugal clutch 100 is configured between a Dedicated Hybrid Transmission (DHT) 02 and an electric motor 04 of a vehicle in accordance to an embodiment of the present subject matter. The input shaft 10 is configured to be connected to the DHT 02 and the output shaft 20 is configured to be connected to the electric motor 04. The DHT 02 is configured to selectively receive rotary drive from a gasoline engine 06 and from the electric motor 04 and transfers to a drive axle 08 of the vehicle. The electric motor 04 generally caters for 20-30% of total power, rest being taken care by the gasoline engine 06. The Dedicated Hybrid Transmission 02 for vehicles operate at maximum vehicle speeds, the electric motor 04 needs to be dis-engaged and protected against the higher RPMs (above 10,000) as the electric motor cannot operate at such high RPMs above its Fly-Up RPM. The electric motor 04 is powered by a dedicated 48 V battery 03, and thus it becomes increasingly important to protect the electric motor 04 and the battery 03 against higher reverse thrust from the DHT 02 either while coasting or while pure gasoline operation modes. The centrifugal clutch 100 is especially designed to protect the electric motor 04 and the battery 03 from any reverse thrust or excessively higher RPMs (>10,000) when vehicle runs at top speed exceeding 150 km/hr.
[0045] The present subject matter discloses a centrifugal clutch 100 comprising a housing 110, a clutch plate 120, a pressure plate 130, and a disengaging means. The disengaging means is configured to disengage the pressure plate 130 and the clutch plate 120 above a predefined speed.
[0046] The housing 110, having frustoconical shape, comprises a conical surface 112, a small side 114 and a large side 116, wherein the housing 110 is configured to receive rotary motion from an input shaft 10 mounted on the small side 114 end of the housing 110. The clutch plate 120 is configured to be securely mounted to the small side 114 of the housing to enable rotation of the clutch plate 120 along with the housing 110.
[0047] The pressure plate 130 and the clutch plate 120 are configured to be engaged below a predefined speed of the clutch plate 120 due to forces applied by the plurality of compression springs 140.The disengaging means comprises plurality of compression springs 140 and at least one ball lever assembly 160 mounted on the pressure plate 130.
[0048] A groove with lining 117 embedded on the large side 116 of the housing is configured to rotatably mount a ring 150. In an embodiment, the groove with lining 117 is configured with a lining removably inserted in the groove. The groove with lining 117 is configured with a material selected from a set of self-lubricating materials such as brass or brass-bronze and bearing material such as Chrome Steel, Stainless Steel, Ceramic, metal alloys and polymers. A first end 140a of the plurality of compression springs 140 is configured to be secured and circumferentially mounted on the ring 150. The second end 140b of the plurality of compression springs 140 are configured to be secured to mounting grooves 131 on the pressure plate 130; for establishing continuous contact with the clutch plate 120 and to provide rotary motion to an output shaft 20.
[0049] The ball lever assembly 160 comprises an inner lever 162, an outer lever 164 and a ball 166. A first end 162a of the inner lever is fixedly mounted to an outer edge of the pressure plate 130. A first end 164a of the outer lever is hingedly mounted to a second end 162b of the inner lever 162. The ball 166 fixedly mounted to a second end 164b of the outer lever 164. The ball 166 is configured to be a dead weight to provide centrifugal force for disengaging the pressure plate 130 and the clutch plate 120.
[0050] A hinge point 163 of the inner lever 162 and the outer lever 164 is configured to provide relative angular movement up to 180° between the inner lever 162 and the outer lever 164.
[0051] The ball lever assembly 160 is configured to expand due to increased centrifugal forces above the predefined speed and the inclination on the conical surface 112 enables the ball lever assembly 160 to slide towards the large side 116 of the housing to disengage the pressure plate 130 from the clutch plate 120 by pressing the pressure plate 130 against the compression springs 140. Further the reduced centrifugal forces below the predefined speed are configured for regaining original position of the ball lever assembly 160 for enabling engagement of the pressure plate 130 with the clutch plate 120, due to the compression springs 140 force, for transferring rotary motion.
[0052] In an embodiment of the present subject matter, the input shaft 10 is configured to be mounted to a Dedicated Hybrid Transmission DHT, 02 and the output shaft 20 is configured to be mounted to an electric motor 04; wherein the DHT 02 is configured to selectively receive rotary drive from a gasoline engine 06 and from the electric motor 04 and transfers to a drive axle 08 of a vehicle. Therefore, the centrifugal clutch 100 is configured to disengage the electric motor 04 from the DHT 02 above a predefined speed to prevent a reverse flow of the rotary drive from the DHT 02 to the electric motor 04.
[0053] In an embodiment of the present subject matter, a process for self-actuation of a centrifugal clutch 100 for disengaging and engaging is disclosed. The process comprises steps of: receiving a rotary motion by a clutch plate 120 from an input shaft 10, expanding a ball lever assembly 160 due to increased centrifugal forces above a predefined speed, sliding the ball lever assembly 160 on a conical surface 112 towards a large side 116 of a housing 110 for pushing a pressure plate 130 against the forces of the compression springs 140 to disengage the pressure plate 130 from the clutch plate 120 to stop the transfer of rotary motion from the input shaft 10 to the output shaft 20, contracting the ball lever assembly 160 due to reduction in centrifugal forces below the predefined speed, and pushing the pressure plate 130 towards the clutch plate 120 by the compression springs 140 and engaging the pressure plate 130 with the clutch plate 120 to enable transfer of rotary motion from the input shaft 10 to the output shaft 20.
[0054] Exemplary embodiments discussed above may provide certain advantages. Though not required to practice aspects of the disclosure, these advantages may include the following.
[0055] Some embodiments of the subject matter enable to provide a centrifugal clutch for disengaging two shafts above a predefined speed.
[0056] Some embodiments of the subject matter enable to protect the electric motor and the battery against higher reverse thrust from the DHT at higher RPMs.
[0057] Some embodiments of the subject matter enable to provide a reverse centrifugal clutch which engages at lower RPMs and disengages above a predefined RPM.
Equivalents
[0058] With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.
[0059] It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as "open" terms (e.g., the term "including" should be interpreted as "including but not limited to," the term "having" should be interpreted as "having at least," the term "includes" should be interpreted as "includes but is not limited to," etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases "at least one" and "one or more" to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles "a" or "an" limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases "one or more" or "at least one" and indefinite articles such as "a" or "an" (e.g., "a" and/or "an" should typically be interpreted to mean "at least one" or "one or more"); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of "two recitations," without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to "at least one of A, B, and C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, and C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances, where a convention analogous to "at least one of A, B, or C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, or C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase "A or B" will be understood to include the possibilities of "A" or "B" or "A and B."
[0060] Although implementations for a centrifugal clutch have been described in language specific to structural features and/or methods, it is to be understood that the appended claims are not necessarily limited to the specific features described. Rather, the specific features are disclosed as examples of implementation for the centrifugal clutch.