Clutch assembly with fixed release bearing

Abstract

A clutch assembly (100) is disclosed having an outer basket (102) and an inner hub (104). The clutch assembly (100) also includes a friction clutch pack (106) installed between the inner hub (104) and the outer basket (102) and adapted to transmit the power from the outer basket (102) to the inner hub (104). The clutch assembly (100) includes a centrifugal mechanism (124) to selectively engage the friction clutch pack (106) to the outer basket (102) and the inner hub (104). The clutch assembly (100) includes a clutch release bearing (134) and a spring device (108) installed between the clutch release bearing (134) and the friction clutch pack (106) to maintain engagement of the clutch release bearing (134) with the friction clutch pack (106) during the engagement of the friction clutch pack (106) and the centrifugal mechanism (124).

Description

FIELD OF THE INVENTIONThe present disclosure relates to a clutch assembly with a release bearing tomaintain constant engage with the clutch pack.BACKGROUNDA clutch unit for a two-wheeler is installed between a prime mover, such asinternal combustion (IC) engine and a transmission unit to transmit the power fromthe prime mover to the transmission unit. The clutch unit includes an outer basketconnected to the engine’s crankshaft and an inner basket connected to atransmission unit. Further, the clutch unit includes a set of clutch plates and a set ofpressure plates stacked alternatively inside the outer basket, such that the clutchplate is in mesh with the outer basket while the pressure plates are in mesh with theinner basket. Furthermore, the inner basket can be spring-loaded and can displacewith respect to the outer basket to engage or disengage with the pressure plate withthe clutch plate to transmit the power or forfeit the power transmission. Onecategory of the clutch unit is a semi-automatic clutch unit that uses a centrifugalmechanism that engages the pressure plates and the clutch plate when the enginespeed exceeds an engagement speed. The semi-automatic clutch unit also includesa lever mechanism that uses a clutch release bearing that, when operated by a clutchlever overrides the centrifugal clutch and disengaged the clutch plate from thepressure plate.One of the main limitations of the semi-automatic clutch unit is that theoperation of the centrifugal clutch momentarily changes the level of the clutchrelease bearing. The change in the level of the clutch release bearing results in theplay in the clutch lever causing a disconnect between the clutch lever and the clutchunit. Moreover, the relative play warrants additional load by the rider’s hand to beapplied on the clutch lever to override the centrifugal clutch thereby making theoperation of the clutch unit inefficient.SUMMARYThis summary is provided to introduce a selection of concepts, in a simplifiedformat, that are further described in the detailed description of the invention. Thissummary is neither intended to identify key or essential inventive concepts of theinvention and nor is it intended for determining the scope of the invention.The present disclosure relates to a clutch assembly for a two-wheeler that hasa spring device that maintains the engagement of the clutch release bearing with theclutch packs irrespective of the operation of the centrifugal mechanism. The springdevice also reduces the change in the load on the clutch lever when the centrifugalclutch is engaging the clutch plate thereby reducing fatigue to the rider.In an embodiment, a clutch assembly for a two-wheeler is disclosed. Theclutch assembly includes an outer basket adapted to receive power from an engineand an inner hub installed coaxially in the outer basket and adapted to transmitpower to a transmission unit. The clutch assembly also includes a friction clutchpack installed in an annular space between the inner hub and the outer basket andadapted to selectively engage the outer basket and the inner hub to transmit thepower from the outer basket to the inner hub. In addition, the clutch assemblyincludes a centrifugal clutch coupled to the outer basket and the friction clutch pack,wherein the centrifugal clutch engages the friction clutch pack to the outer basketand the inner hub when an engine speed exceeds a predetermined threshold value.The clutch assembly includes a clutch release bearing slidably installed at aside of the friction clutch pack and adapted to engage and disengage the frictionclutch pack from the inner hub and the outer basket in response to driver input. Inaddition, the clutch assembly a spring device installed between the clutch releasebearing and the friction clutch pack, wherein the spring device is adapted tomaintain engagement of the clutch release bearing with the friction clutch packduring the engagement of the friction clutch pack and the centrifugal clutch withthe outer basket and the inner hub, respectively.According to the present disclosure, the spring device ensures constantengagement of the friction clutch pack and the clutch release bearing. Such aconstant engagement ensures that there are no vibrations in the clutch lever. As aresult, the clutch lever life is prolonged.To further clarify advantages and features of the present invention, a moreparticular description of the invention will be rendered by reference to specificembodiments thereof, which is illustrated in the appended drawings. It isappreciated that these drawings depict only typical embodiments of the inventionand are therefore not to be considered limiting of its scope. The invention will bedescribed and explained with additional specificity and detail with theaccompanying drawings.BRIEF DESCRIPTION OF THE DRAWINGSThese and other features, aspects, and advantages of the present invention willbecome better understood when the following detailed description is read withreference to the accompanying drawings in which like characters represent likeparts throughout the drawings, wherein:Figure 1 illustrates a cross section of a clutch assembly, according to anembodiment of the present disclosure;Figure 2 illustrates a partially exploded view of the clutch assembly showingthe, according to an embodiment of the present disclosure; andFigure 3 illustrates a cross-section of the portion of the clutch assembly theworking of the spring device, according to an embodiment of the present disclosure.Further, skilled artisans will appreciate that elements in the drawings areillustrated for simplicity and may not have necessarily been drawn to scale.Furthermore, in terms of the construction of the device, one or more components ofthe device may have been represented in the drawings by conventional symbols,and the drawings may show only those specific details that are pertinent tounderstanding the embodiments of the present invention so as not to obscure thedrawings with details that will be readily apparent to those of ordinary skill in theart having benefit of the description herein.DETAILED DESCRIPTION OF FIGURESFor the purpose of promoting an understanding of the principles of theinvention, reference will now be made to the embodiment illustrated in the drawingsand specific language will be used to describe the same. It will nevertheless beunderstood that no limitation of the scope of the invention is thereby intended, suchalterations and further modifications in the illustrated system, and such furtherapplications of the principles of the invention as illustrated therein beingcontemplated as would normally occur to one skilled in the art to which theinvention relates. Unless otherwise defined, all technical and scientific terms usedherein have the same meaning as commonly understood by one of ordinary skilledin the art to which invention belongs. The system and examples provided herein areillustrative only and not intended to be limiting.For example, the term “some” as used herein may be understood as “none”or “one” or “more than one” or “all.” Therefore, the terms “none,” “one,” “morethan one,” “more than one, but not all” or “all” would fall under the definition of“some.” It should be appreciated by a person skilled in the art that the terminologyand structure employed herein is for describing, teaching, and illuminating someembodiments and their specific features and elements and therefore, should not beconstrued to limit, restrict or reduce the spirit and scope of the present disclosure inany way.For example, any terms used herein such as, “includes,” “comprises,” “has,”“consists,” and similar grammatical variants do not specify an exact limitation orrestriction, and certainly do not exclude the possible addition of one or morefeatures or elements, unless otherwise stated. Further, such terms must not be takento exclude the possible removal of one or more of the listed features and elements,unless otherwise stated, for example, by using the limiting language including, butnot limited to, “must comprise” or “needs to include.”Whether or not a certain feature or element was limited to being used onlyonce, it may still be referred to as “one or more features” or “one or more elements”or “at least one feature” or “at least one element.” Furthermore, the use of the terms“one or more” or “at least one” feature or element do not preclude there being noneof that feature or element, unless otherwise specified by limiting languageincluding, but not limited to, “there needs to be one or more...” or “one or moreelements is required.”Unless otherwise defined, all terms and especially any technical and / orscientific terms, used herein may be taken to have the same meaning as commonlyunderstood by a person ordinarily skilled in the art.Reference is made herein to some “embodiments.” It should be understoodthat an embodiment is an example of a possible implementation of any featuresand / or elements of the present disclosure. Some embodiments have been describedfor the purpose of explaining one or more of the potential ways in which the specificfeatures and / or elements of the proposed disclosure fulfil the requirements ofuniqueness, utility, and non-obviousness.Use of the phrases and / or terms including, but not limited to, “a firstembodiment,” “a further embodiment,” “an alternate embodiment,” “oneembodiment,” “an embodiment,” “multiple embodiments,” “some embodiments,”“other embodiments,” “further embodiment”, “furthermore embodiment”,“additional embodiment” or other variants thereof do not necessarily refer to thesame embodiments. Unless otherwise specified, one or more particular featuresand / or elements described in connection with one or more embodiments may befound in one embodiment, or may be found in more than one embodiment, or maybe found in all embodiments, or may be found in no embodiments. Although oneor more features and / or elements may be described herein in the context of only asingle embodiment, or in the context of more than one embodiment, or in thecontext of all embodiments, the features and / or elements may instead be providedseparately or in any appropriate combination or not at all. Conversely, any featuresand / or elements described in the context of separate embodiments may alternativelybe realized as existing together in the context of a single embodiment.Any particular and all details set forth herein are used in the context of someembodiments and therefore should not necessarily be taken as limiting factors tothe proposed disclosure.Embodiments of the present invention will be described below in detail withreference to the accompanying drawings.For the sake of clarity, the first digit of a reference numeral of each componentof the present disclosure is indicative of the Figure number, in which thecorresponding component is shown. For example, reference numerals starting withdigit “1” are shown at least in Figure 1. Similarly, reference numerals starting withdigit “2” are shown at least in Figure 2.Figures 1, 2, and 3 illustrate a clutch assembly 100 for a vehicle, according toan embodiment of the present disclosure. Specifically, Figure 1 illustrates a crosssectional view of a clutch assembly while Figure 2 illustrates a partially explodedview of the clutch assembly 100. Further, Figure 3 illustrates a zoom-in portion ofthe cross-section of the clutch assembly 100 in Figure 1. The clutch assembly 100may be employed in a two-wheeler having a two-wheeler’s prime mover, such assuch as an internal combustion engine (ICE) to provide. The clutch assembly 100is configured to transmit power from the engine to a transmission unit, such as agearbox. The clutch assembly 100 is adapted to engage with a flywheel of the primemover to transfer the power. The clutch assembly 100 may be designed to receivetorsional vibrations and may be adapted to undergo angular deflection by a greaterdegree than conventional clutches. The clutch assembly 100 may include but is notlimited to, an outer basket 102, an inner hub 104, a friction clutch pack 106, and aspring device 108 among other examples, details of which will be provided insubsequent paragraphs.The outer basket 102 may form a major and outer portion of the clutchassembly 100. The outer basket 102 may house various components of the clutchassembly 100. The outer basket 102 may be operably coupled to an engine flywheel.The outer basket 102 has an input gear 110 attached thereto, for instance, usingfasteners that are in mesh from a gear around the flywheel. The outer basket 102has a hole 110A at its centre. In addition, the outer basket 102 also has a pluralityof the seats to install a plurality of dampers 112. The dampers 112 are configuredto absorb the vibration during the operation of the clutch assembly 100. Thedampers 112 can be helical spring arranged circumferentially on a base of the outerbasket 102.In addition, the inner hub 104 is installed coaxially in the outer basket 102and adapted to transmit power to a transmission unit. The inner hub 104 mayinclude a pressure plate 114 that is connected to an output shaft 116 of the clutchassembly 100. The output shaft 116 may pass through the central hole 110A andact as an input shaft of the transmission unit. Although not visible, the inner hub104 includes a plurality of mounting fasteners that secures the inner hub 104 to theouter basket 102 in such a way that the inner hub 104 can selectively engage withthe outer basket 102. The inner hub 104 also includes a plurality of helical springs118 that is installed longitudinally in the inner hub 104.As shown in Figure 1 clearly, the friction clutch pack 106 is installed in anannular space between the inner hub 104 and the outer basket 102. The frictionclutch pack 106 is configured to selectively engage the inner hub 104 and the outerbasket 102 to either transmit the power or cut off the transmission of power. Thefriction clutch pack 106 includes a plurality of clutch plates 120 and a plurality ofsteel plates 122. Further, the clutch plates 120 and the steel plates 122 arealternatively stacked between the inner hub 104 and the outer basket 102. As shownclearly in Figure 2, the friction clutch plate 120 have external teeth on theirperiphery which engages with U-shaped cut-out sections 124 of the outer basket102 so that the friction clutch plate 120 rotates with the outer basket 102. On theother hand, the steel plates 122 have internal teeth that are in mesh with externalteeth on the inner hub 104. Furthermore, the friction clutch plates 120 and the steelplates 122 can be pressed together so that the friction clutch plates 120 rotating withthe outer basket 102 are engaged with the steel plates 122 making them rotate andconsequently, the inner hub 104 thereby transmitting the power.In an example, the clutch assembly 100 may include a centrifugal mechanism126 installed between the inner hub 104 and the outer basket 102. The centrifugalmechanism 126 is configured to engage the friction clutch pack 106 with the innerhub 104 to the outer basket 102 when the engine speed exceeds a predeterminedthreshold value. The centrifugal mechanism 126 is a dual-mass mechanism andincludes a pair of masses 128A, 128B. The masses 128A, 128B are installed insidethe outer basket 102, such that the masses 128A, 128B can slide radially inwardlyand outwardly and inwardly to engage and disengage respectively the friction clutchpack 106. The centrifugal mechanism 126 may also include racks 130 each of themasses 128A, 128B that slides orthogonally with respect to the sliding of the masseswhen the masses 128A, 128B slide radially outward. The centrifugal mechanism126 also include an engagement spring 132 that couples the rack 130 to the frictionclutch pack 106. In one example, the engagement spring 132 may push the frictionclutch plates 120 against the steel plates 122 when the rack 130 moves upward.During the operation, the centrifugal mechanism 126 rotates with the outerbasket 102 and remains at their neutral position as shown in Figure 1 when theengine is idling. Further, as the engine speed increases, the centrifugal mechanism126 starts sliding radially outwardly causing the rack 130 to slide upward. Theupward sliding of the rack 130 pushes the engagement spring 132 which in turnapplies the clamp load on the friction clutch plates 120 and the steel plates 122causing them to engage to transmit the power from the outer basket 102 to thefriction clutch plate 120, and from the friction clutch plate 120 to the pressure disc122 and finally to the inner hub 104. From the inner hub 104 power goes to theoutput shaft 116 and finally to the transmission unit.The clutch assembly 100 includes a clutch release bearing 134 that isconfigured to override the engagement of the centrifugal mechanism 126. Further,the clutch release bearing 134 is slidably installed at a side of the friction clutchpack 106 and can engage or disengage the friction clutch pack 106 from the innerhub and the outer basket in response to driver input. For instance, the clutch releasebearing 134 may receive the driver input from a clutch lever and may disengage thefriction clutch pack 106 from the inner hub 104 and the outer basket 102 when thedriver does not require power at the wheelsGenerally, engagement of the friction clutch pack 106 by a centrifugalmechanism causes the friction clutch pack to slide down under compression causingmomentary disengagement of the clutch release bearing 134 from the friction clutchpack 106. Such disengagement may result in the disconnect of the clutch lever fromthe friction clutch pack 106 resulting in the loss of clutch override. As a result, moreload and travel needs to be applied to the clutch lever to establish the connection.In one example, the load difference may be around 50 Newtons which can causefatigue to the rider.Such a scenario is avoided by the spring device 108 which is installed betweenthe friction clutch pack 106 and the clutch release bearing 134. The spring device108 is adapted to maintain engagement of the clutch release bearing 134 with thefriction clutch pack 106 during the engagement of the friction clutch pack 106 andthe centrifugal mechanism 126 with the outer basket 102 and the inner hub 104,respectively. The spring device 108 can either be a Belleville spring or a wavespring. In one example, the spring device 108 may be housed in a release guide 136.The release guide 136 may also house the clutch release bearing 134. The releaseguide 136 includes a set of lips 138 that engages with the protrusions 140 on theinner hub 104 to enable the clutch release bearing 134 and the spring device 108 torotate at the same speed as the inner hub 104.According to the present disclosure, the spring device 108 is designed andsized to sit between the clutch release bearing 134 and the friction clutch pack 106.In a neutral position, the spring device 108 may be compressed between the clutchrelease bearing 134 and the friction clutch pack 106. Further, when the frictionclutch pack 106 is actuated by the centrifugal mechanism 126, the spring device108 may get de-energized thereby maintaining the contact both with the frictionclutch pack 106 and the clutch release bearing 134 thereby maintaining engagementof the clutch release bearing 134 to the friction clutch pack 106.Referring now to Figure 4 that indicates a graph 400 between clutch releaseload on the clutch and the clutch lever release travel. Further, line 402 indicatesclutch release load maintained by the spring device at the driving position whileline 404 indicates clutch release load maintained by the spring device 108 at idleposition. Further, line 406 indicates clutch release load at an idle position when thespring device 108 is absent. As may be understood, the almost nil load at idleindicated by line 406 results in a greater load difference L1 which the rider needsto apply to override the clutch. In one example, load difference L1 can be around50 Newtons.On the other hand, the spring device 108 maintain the clutch lever in itsposition when the rider is not operating the clutch lever owing to the fact that theposition of the clutch release bearing 134 remains at its position unlike inconventional in which the clutch release bearing slides when the centrifugal clutchengages the friction clutch pack. As a result, a relatively less amount of loaddifference L2 is to be applied by the rider to override the centrifugal mechanism. Inone example, the load difference can be around 30 Newtons.Therefore, a smaller load difference in clutch release load reduces fatigue tothe rider. Moreover, constant engagement also ensures the rider has completecontrol over the operation of the clutch assembly 100 and enables the override ofthe centrifugal mechanism 126. The spring device is also a serviceable componentthat can easily be replaced in case the spring loses its spring force thereby makingthe clutch assembly 100 easily repairable.While specific language has been used to describe the present disclosure, anylimitations arising on account thereto, are not intended. As would be apparent to aperson in the art, various working modifications may be made to the method inorder to implement the inventive concept as taught herein. The drawings and theforegoing description give examples of embodiments. Those skilled in the art willappreciate that one or more of the described elements may well be combined into asingle functional element. Alternatively, certain elements may be split into multiplefunctional elements. Elements from one embodiment may be added to anotherembodiment.

Claims

1. A clutch assembly (100) for a two-wheeler comprising: an outer basket (102) adapted to receive power from an engine; an inner hub (104) installed coaxially in the outer basket (102) and adapted to transmit power to a transmission unit; a friction clutch pack (106) installed in an annular space between the inner hub (104) and the outer basket (102) and adapted to selectively engage the outer basket (102) and the inner hub (104) to transmit the power from the outer basket (102) to the inner hub (104); a centrifugal mechanism (126) coupled to the outer basket (102) and the friction clutch pack (106), wherein the centrifugal mechanism (126) engages the friction clutch pack (106) to the outer basket (102) and the inner hub (104) when an engine speed exceeds a predetermined threshold value; a clutch release bearing (134) slidably installed at a side of the friction clutch pack (106) and adapted to engage and disengage the friction clutch pack (106) from the inner hub (104) and the outer basket (102) in response to a driver input; and a spring device (108) installed between the clutch release bearing (134) and the friction clutch pack (106), wherein the spring device (108) is adapted to maintain engagement of the clutch release bearing (134) with the friction clutch pack (106) during the engagement of the friction clutch pack (106) and the centrifugal mechanism (126) with the outer basket (102) and the inner hub (104), respectively.

2. The clutch assembly (100) as claimed in claim 1, wherein the friction clutch pack (106) comprising: a plurality of friction clutch plates (120) having external teeth in mesh with slots of the outer basket (102); and a plurality of steel plates (122) slidably disposed along a central axis of the outer basket (102) and having internal teeth in mesh with the inner hub (104) and adapted to selectively engage with the plurality of friction clutch plates (120), wherein the plurality of friction clutch plates (120) is pressed against the plurality of steel plates (122) by the spring device (108) upon actuation by the clutch release bearing (134).

3. The clutch assembly (100) as claimed in claim 1, wherein the spring device (108) is one of a Belleville spring and a wave ring spring.

4. The clutch assembly (100) as claimed in claim 1, comprising a release guide (136) interposed between the friction clutch pack (106) and the clutch release bearing (134) and adapted to house the spring device (108).

5. The clutch assembly (100) as claimed in claim 1, wherein the centrifugal mechanism (126) is a dual mass centrifugal mechanism (126).

6. A two-wheeler vehicle comprising: an engine to provide power; and a clutch assembly (100) coupled to the engine to selectively transmit the power from the engine to a transmission unit, the clutch assembly (100) comprising: an outer basket (102) adapted to receive power from an engine; an inner hub (104) installed coaxially in the outer basket (102) and adapted to transmit power to a transmission unit; a friction clutch pack (106) installed in an annular space between the inner hub (104) and the outer basket (102) and adapted to selectively engage the outer basket (102) and the inner hub (104) to transmit the power from the outer basket (102) to the inner hub (104); a centrifugal mechanism (126) coupled to the outer basket (102) and the friction clutch pack (106), wherein the centrifugal mechanism (126) engages the friction clutch pack (106) to the outer basket (102) and the inner hub (104) when an engine speed exceeds a predetermined threshold value; a clutch release bearing (134) slidably installed at a side of the friction clutch pack (106) and adapted to engage and disengage the friction clutch pack (106) from the inner hub (104) and the outer basket (102) in response to a driver input; and a spring device (108) installed between the clutch release bearing (134) and the friction clutch pack (106), wherein the spring device (108) is adapted to maintain engagement of the clutch release bearing (134) with the friction clutch pack (106) during the engagement of the friction clutch pack (106) and the centrifugal mechanism (126) with the outer basket (102) and the inner hub (104), respectively.

7. The two-wheeler as claimed in claim 6, wherein the friction clutch pack (106) comprising: a plurality of friction clutch plates (120) having external teeth in mesh with slots of the outer basket (102); and a plurality of steel plates (122) slidably disposed along a central axis of the outer basket (102) and having internal teeth in mesh with the inner hub (104) and adapted to selectively engage with the plurality of friction clutch plates (120), wherein the plurality of friction clutch plates (120) is pressed against the plurality of steel plates (122) by the spring device (108) upon actuation by the clutch release bearing (134).

8. The two wheeled vehicle as claimed in claim 6, wherein the spring device (108) is one of a Belleville spring and a wave ring spring.

9. The two wheeled vehicle as claimed in claim 6, comprising a release guide (136) interposed between the friction clutch pack (106) and the clutch release bearing (134) and adapted to house the spring device (108).

10. The two wheeled vehicle as claimed in claim 6, wherein the centrifugal mechanism (126) is a dual mass centrifugal mechanism (126).