Clutch with centrifugal assembly for motorcycles

Abstract

The invention relates to a clutch comprising a fixed hub (101), a movable hub (102) and a plurality of plates (103) inserted to selectively transmit torque. The clutch further comprises a centrifugal plate packing assembly (200) comprising a mass carrier (201), a plurality of radially movable mass elements (202), wherein each mass element (202) comprises a pivot (203) connected to the mass carrier (201) for displacement under centrifugal effect towards an outer position, wherein the mass elements (202) are further configured to exert an axial thrust on a thrust surface (204) of the centrifugal plate packing assembly (200) to bring the movable hub (102) closer to the fixed hub (103) and increase the variable axial load. Each mass element (202) comprises at least one respective rolling element (205) in contact with the thrust surface (204). The thrust surface (204) comprises a profile inclined and bulging towards the outer position.

Description

Technical Field

[0001] This invention relates to a clutch, particularly a clutch for motorcycles.

[0002] In general, the present invention relates to a clutch comprising a fixed hub and a movable hub, wherein a plurality of clutch plates are inserted between the fixed hub and the movable hub, and torque can be transmitted when the clutch plates are axially pushed toward each other. The clutch includes a centrifugal assembly adapted to axially push the fixed hub and the movable hub closer together according to the clutch rotational speed. Background Technology

[0003] Adler S.pA's document EP2400177(A1) relates to a clutch having an automatic engagement device and simultaneously equipped with a manual operation device. The clutch includes a centrifugal assembly in which a rotatably coupled mass block is displaced under centrifugal effect and engages with a pressure ring to cause axial compression of the plate assembly in order to achieve clutch engagement.

[0004] Document GB995989(A) relates to a clutch activated by a centrifugal mechanism, including a centrifugal counterweight acting on a pressure plate.

[0005] Adler S.pA’s document WO2019 / 101342(A1) relates to a clutch with a centrifugal assembly, comprising a plurality of mass elements arranged radially in a mass retainer, wherein each mass element includes a body and a cylindrical element connected to a pivot point.

[0006] Document EP2175154(A2) relates to a centrifugal multi-plate friction clutch comprising: a centrifugal counterweight configured to receive centrifugal force by rotating together with the clutch housing and to move in a direction away from the axial center of the clutch shaft; and a cam mechanism configured to convert the centrifugal force into an axial force by contacting the centrifugal counterweight.

[0007] Document JP2012241804(A) relates to a multi-plate automatic centrifugal clutch device, which includes a centrifugal roller that presses the drive plate and the driven plate together by centrifugal force generated by the rotation of the driven shaft to rub against each other.

[0008] Document DE1087460(B) relates to a centrifugal clutch having rolling elements as centrifugal counterweights, particularly for motor vehicles, wherein each centrifugal counterweight consists of several rotatably interconnected roller-like rolling elements of different diameters, and the centrifugal counterweights are arranged to move freely between two mutually inclined control surfaces.

[0009] Existing technological solutions allow for the automatic engagement and disengagement of centrifugal clutches.

[0010] However, centrifugal clutches based on existing technology can be improved in terms of operational smoothness, especially in improving the riding experience of motorcycles.

[0011] In particular, existing technological solutions can be improved in terms of engagement smoothness over a wider range of speeds. Torque transmission in automatic centrifugal clutches can also be further optimized, especially for torque transmission in motorcycles.

[0012] For example, the performance of a centrifugal clutch during engagement may provide a different driving feel than the same centrifugal clutch during disengagement, thus degrading the user's driving experience. These performance differences may even worsen as the clutch plates gradually wear down.

[0013] Typically, in known centrifugal clutches, there is a friction problem and the resulting operational hysteresis involving the centrifugal pressure plate assembly acting on the hub. This hysteresis means that the torque transmitted by the clutch is not always linear, as it depends on the amount of rpm and also on the driving conditions. Specifically, at the same speed, a centrifugal clutch may tend to slip during acceleration or throttle opening, and may tend to jam during deceleration or throttle closing. Summary of the Invention

[0014] The purpose of this invention is to solve certain problems in the prior art.

[0015] A particular object of the present invention is to provide a centrifugal clutch that has good operation and provides a comfortable user experience.

[0016] Another specific object of the present invention is to improve the smoothness of engagement and disengagement of the centrifugal clutch, preferably for a wider range of speeds.

[0017] Another specific object of the present invention is to provide a clutch that optimizes torque transmission even during transitions from low to high speeds and during the reverse transitions from high to low speeds.

[0018] Another specific objective of this invention is to alleviate the friction problem and the resulting operational lag in centrifugal clutches.

[0019] Another specific objective is to provide an improved centrifugal clutch that allows for both automatic and manual operation, particularly for efficient use on motorcycles.

[0020] Another specific object of the present invention is to provide a clutch that provides reliable operation.

[0021] Another specific object of the present invention is to provide a compact clutch, particularly a compact clutch for effective use on motorcycles.

[0022] Another specific object of the present invention is to provide a clutch whose performance is improved under engine braking conditions.

[0023] These and other objectives are achieved by the clutch and the associated transmission system, as set forth in the appended claims that form part of this specification.

[0024] The underlying solution concept of this invention is to provide a centrifugal clutch that includes a centrifugal plate pressing assembly capable of at least partially controlling the variable axial load on the clutch plates.

[0025] The centrifugal tableting assembly includes a mass carrier configured to rotate with the clutch and a plurality of radially movable mass elements in the centrifugal tableting assembly, wherein each mass element includes a pivot connected to the mass carrier and is thus configured to be displaced to an external position under centrifugal effect.

[0026] By means of this displacement under centrifugal effect, the mass element is also configured to apply axial thrust to the thrust surface of the centrifugal tableting assembly, thereby bringing the movable hub closer to the fixed hub and increasing the variable axial load.

[0027] Each mass element includes at least one corresponding rolling element that contacts the thrust surface. Advantageously, the presence of the rolling element allows for reduced sliding friction between the mass element and the thrust surface. In this way, hysteresis is advantageously reduced as engine rpm changes, improving operation related to transmitted torque and allowing for better adjustability of the clutch, particularly during start-up.

[0028] The thrust surface includes a profile that is inclined and convex toward the external location. Preferably, the profile may include a curved portion. Advantageously, the inclined profile allows the rotational angular velocity of the clutch to be stably correlated with the axial load, thereby allowing better control of the clutch in transmitting torque, and in particular allowing the initial engagement of the clutch to be less abrupt during start-up.

[0029] In summary, the centrifugal clutch of this invention allows users to operate more smoothly and enjoyably.

[0030] In particular, the centrifugal clutch of the present invention optimizes torque transmission during the transition from low speed to high speed and during the reverse transition from high speed to low speed.

[0031] Preferably, the centrifugal clutch has a fixed hub and a movable hub, the fixed hub including a first sliding element and the movable hub including a second sliding element, the first sliding element and the movable hub being configured to engage with each other and slide against each other when subjected to a torque acting on the clutch, so as to at least partially change the variable axial load.

[0032] In this way, a further closing effect of the clutch plates can be advantageously achieved, thereby increasing the torque that can be transmitted by the clutch in the event of sudden acceleration or engine braking. Advantageously, the centrifugal clutch according to the invention improves the increase in torque that the clutch can transmit under acceleration conditions, while preventing undesirable losses during engine braking under braking or deceleration conditions, in which case the centrifugal clamping assembly should tend to open the clutch plates.

[0033] Generally, the good operation of the centrifugal clutch according to the invention is particularly advantageous for applications in motorcycles, especially high-performance motorcycles, thereby allowing for an excellent riding experience.

[0034] Other features and advantages will be apparent from the following detailed description of preferred, non-limiting embodiments of the invention and from the dependent claims that outline preferred and particularly advantageous embodiments of the invention. Attached Figure Description

[0035] The invention is described with reference to the following accompanying drawings, which are provided by way of non-limiting example, in which:

[0036] Figure 1 A cross-sectional view of an embodiment of the clutch according to the present invention is shown.

[0037] Figure 2 A three-dimensional view of an embodiment of a mass element for a clutch according to the present invention is shown.

[0038] Figure 3 An enlarged cross-sectional view of the clutch centrifugal pressing assembly according to the present invention is shown.

[0039] Figure 4 The first part of the centrifugal tableting assembly in a first closed configuration is shown.

[0040] Figure 5 It shows Figure 4 The second part of the centrifugal tableting assembly in the first closed configuration.

[0041] Figure 6 The first part of the centrifugal tableting assembly in the second intermediate configuration is shown.

[0042] Figure 7 It shows Figure 6The second part of the centrifugal tableting assembly in the second intermediate configuration.

[0043] Figure 8 The first part of the centrifugal tableting assembly in the third open configuration is shown.

[0044] Figure 9 It shows Figure 8 The second part of the centrifugal tableting assembly in the third open configuration.

[0045] Figure 10 A partial three-dimensional view of a sub-assembly of the clutch hub assembly according to the present invention is shown.

[0046] Figure 11 A three-dimensional view of the fixed hub and the movable hub of the clutch according to the present invention is shown.

[0047] Figure 12 A cross-sectional view of another embodiment of the clutch according to the present invention is shown.

[0048] Figure 13 A three-dimensional view of an embodiment of the overtravel spring according to the present invention is shown.

[0049] In different figures, similar reference numerals will be used to indicate similar elements. In the case of several elements of the same type shown in the same figure, only one or some will be explicitly indicated by the corresponding reference numerals, while the other elements will be considered to be included by analogy. Detailed Implementation

[0050] Figure 1 A cross-sectional view of an embodiment of the clutch 100 according to the present invention is shown.

[0051] In this embodiment, the clutch 100 is used to control the engagement of the rotational movement between the drive shaft and the main gear, which engages with the clutch housing of the vehicle, particularly the motorcycle.

[0052] The clutch 100 includes a fixed hub 101, which is specifically configured to be connected to a rotating shaft 10 of the vehicle on which the clutch is mounted. The fixed hub 101 is preferably attached to the main shaft 10 of the gearbox.

[0053] Then, the clutch 100 includes a movable hub 102, which is configured to be mounted on the fixed hub 101 in the axial direction.

[0054] The clutch 100 includes a plurality of plates 103 inserted between a fixed hub 101 and a movable hub 102. In this sense, the clutch 100 is a "multi-plate clutch" type.

[0055] In this embodiment, plate 103 includes a plurality of clutch plates or drive plates, particularly coated plates, which include protruding elements configured to engage with clutch housing 11, which is preferably connected to the drive shaft of the vehicle. Plate 103 also includes a plurality of driven plates, the driven plates including internal teeth configured to engage with movable hub 102 and arranged alternately relative to the drive plates.

[0056] Typically, the clutch housing has a housing 11 that rotates about a rotation axis, located outside the fixed hub 101. The fixed hub 101 is configured to be connected to a shaft 10 coaxial with the rotation axis. A movable hub 102 is axially mounted on the fixed hub 101 along the rotation axis.

[0057] Alternatively, preferably, the clutch 100 includes an annular resonant spring 104 positioned on top of the first plate of the plates 103 and near a flange on the movable hub 102. In a variation, the resonant spring 104 may be replaced by a dual-spring system, each having half the travel of the resonant spring 104; in this way, the smoothness of the initial engagement of the clutch can be improved.

[0058] The fixed hub 101 and the movable hub 102 are configured to rotate together when axially mounted; therefore, the fixed hub 101 and the movable hub 102 are adapted to receive torque.

[0059] In addition, the fixed hub 101 and the movable hub 102 are configured to slide axially respectively, moving away from or closer to each other in a manner that reduces or increases the intensity of the axial load on the plate 103.

[0060] In this way, the fixed hub 101 and the movable hub 102 apply a variable axial load to the plates 103, such that when the plates 103 are compressed together by the axial load, the clutch 100 allows torque to be transmitted between the housing and the rotating shaft of the engine; on the other hand, when the axial load decreases and the plates 103 slide freely on each other, the clutch disengages due to the sufficient spacing between the fixed hub 101 and the movable hub 102, and essentially no torque is transmitted.

[0061] In this way, the clutch 100 can selectively transmit torque between the two rotating shafts according to external control. This external control can be manual, lever or pedal actuated, or of the type implemented by a servo mechanism.

[0062] Furthermore, the clutch 100 further includes a centrifugal pressing plate assembly 200 to at least partially control the variable axial load acting on the plate 103.

[0063] The centrifugal tableting assembly 200 includes a mass carrier 201 configured to rotate with the clutch 100.

[0064] The centrifugal tableting assembly 200 further includes a plurality of mass elements 202 that are radially movable within the centrifugal tableting assembly 200. Each mass element 202 includes a pivot 203 connected to a mass carrier 201, allowing the mass element 202 to be displaced to an external position under centrifugal effect.

[0065] By displacement under centrifugal effect, mass element 202 is further configured to apply axial thrust on thrust surface 204 of centrifugal tablet assembly 200 to bring movable hub 102 closer to fixed hub 101 and increase variable axial load acting on tablet 103.

[0066] Therefore, clutch 100 is defined as a centrifugal clutch, which means that it includes automatic operation due to centrifugal pressure plate assembly 200, but at the same time allows manual operation during gear shifting.

[0067] It should generally be understood that the clutch based on the present invention can be a wet clutch type or a dry clutch type.

[0068] Figure 2 A three-dimensional view of an embodiment of the mass element 202 of the clutch according to the present invention is shown.

[0069] Each mass element 202 in the clutch 100 includes at least one corresponding rolling element 205, which is configured to contact the thrust surface 204.

[0070] In this embodiment, there is a pair of roller-type rolling elements 205 that pivot on corresponding axes within the mass element 202. Different types of rolling elements 205 can be provided, for example, those with additional roller bearings or those that pivot directly on the mass element. A model with only one rolling element 205 is also conceivable.

[0071] As can be seen, the mass element 202 includes a body 206, which includes a rolling element 205, and further includes a substantially elongated column element 207 that connects the pivot 203 to the body 206.

[0072] The column element 207 is configured to increase the lever arm, which facilitates displacement of the mass element 202 in the centrifugal tableting assembly 200 under the centrifugal effect.

[0073] Figure 3 An enlarged cross-sectional view of the centrifugal tableting assembly 200 according to the invention is shown. In this cross-sectional view, one of the rolling elements 205 is visible, while the pivot 203 is not visible and is actually located at a different section.

[0074] As described above, by displacement under centrifugal effect, mass element 202 is configured to apply axial thrust on thrust surface 204 of centrifugal tablet assembly 200. In this way, by using centrifugal effect, movable hub 102 can be brought closer to fixed hub 101 and the variable axial load acting on tablet 103 can be increased.

[0075] The thrust surface 204 includes a profile that is tilted and raised toward the outermost position of the mass element 202 in the centrifugal tableting assembly 200.

[0076] The tilted and raised profile allows for a gradual increase in the axial load acting on the sheet due to the opening of the mass element 202, and this axial load acts on the thrust surface through the interaction of the rolling elements 205.

[0077] Typically, the inclined profile of the thrust surface 204 allows the rotational angular velocity of the clutch to be correlated with the axial load, since the centrifugal effect on the mass element 202 depends on the angular velocity, and these elements (open in the centrifugal pressing assembly 200) provide a gradually increasing load and help to close the fixed hub 101 and movable hub 102 acting on the plate 103.

[0078] Preferably, the inclined profile includes a bend 301 having an increasing slope toward the outermost position of the mass element 202 in the centrifugal tablet assembly 200. In other words, the bend 301 appears to have a concave surface where the rolling element 205 engages.

[0079] The bending portion 301 is configured such that when the mass element 202 opens due to centrifugal effect, the thrust angle of the rolling element 205 on the thrust surface 204 increases. This helps to improve the gradualness of the axial load acting on the plate 103 during the centrifugal opening of the mass element 202.

[0080] The operation and effect of the curved section 301 will be more apparent when considering the different operating configurations of the centrifugal tableting assembly 200 described with reference to the following figures.

[0081] Figure 4 The first portion of the centrifugal tablet assembly 200 is shown, with the rolling element 205 visible, in a first closed configuration at the innermost mass element. This first closed configuration corresponds to an operating state where the clutch 100 is substantially disengaged and no axial load is acting on the tablet 103, particularly for an engine rotating at idle speed.

[0082] In the first closed configuration, the bend 301 defines a first pressure angle 401, which is defined between the axial direction of the variable axial load acting on the plate 103 and the direction of the load exchanged between the rolling element 205 and the thrust surface 204, the direction of which is perpendicular to the tangent of the thrust surface 204 at the contact point, which is now substantially internal.

[0083] Figure 5 It shows Figure 4 The second part of the centrifugal tableting assembly, in which the body 206 of the mass element 202 and the column element 207 are visible, is still in the first closed configuration.

[0084] In this view, it can be understood that the mass element 202 has a center of mass within the body 206, and the column element 207 defines a pivot 203, which is axially positioned relative to the axis of rotation on the clutch 100 further outward than the center of mass in the radial direction. This helps to increase the centrifugal effect and thrust provided by the mass element 202.

[0085] Figure 6 It shows the corresponding Figure 4 The first part of the centrifugal tablet assembly 200 is in a second intermediate configuration, in which the mass element has begun its radial displacement. This second intermediate configuration corresponds to the operating state in which the clutch 100 begins to engage, thereby generating a moderate axial load acting on the tablet 103, particularly for engine speeds just above idling and up to moderate speeds, typically corresponding to the standby start condition.

[0086] In the second intermediate configuration, the bend 301 defines a second pressure angle 402, which is still defined between the axial direction of the variable axial load acting on the plate 103 and the direction of the load exchanged between the rolling element 205 and the thrust surface 204, the direction of which is perpendicular to the tangent of the thrust surface at the contact point, which is now further out.

[0087] The second pressure angle 402 in the second intermediate configuration is greater than the first pressure angle 401 in the first closed configuration.

[0088] Figure 7 The centrifugal tableting assembly 200 in the second intermediate configuration already described is shown. Figure 5 The second part.

[0089] Figure 8 It shows the corresponding Figure 4 and Figure 6The first part of the centrifugal tablet assembly 200 is in a third open configuration, in which the mass element has fully completed its radial displacement. This third open configuration corresponds to the fully engaged operating state of the clutch 100, providing an axial load acting on the tablet 103 that fully transmits the torque acting on the clutch, particularly for medium to high engine speeds, which typically correspond to driving and / or acceleration conditions.

[0090] In the third open configuration, the bend 301 defines a third pressure angle 403, which is also defined between the axial direction of the variable axial load acting on the plate 103 and the direction of the load exchanged between the rolling element 205 and the thrust surface 204, the direction of which is perpendicular to the tangent of the thrust surface 204 at the contact point, which is now even further away.

[0091] The third pressure angle 403 in the third open configuration is greater than the first pressure angle 401 in the first closed configuration and the second pressure angle 402 in the second intermediate configuration.

[0092] Figure 9 The centrifugal tableting assembly 200 in the third open configuration described above is shown in the diagram. Figure 5 and Figure 7 The second part.

[0093] In this third opening configuration, the centrifugal tableting assembly 200 has essentially completed its centrifugal opening.

[0094] Specifically, the mass carrier 201 is configured to limit the radial displacement of the mass element 202 to achieve a maximum open configuration at a predetermined rotational speed of the clutch 100. Specifically, the mass carrier 201 includes an abutment portion located further outward than the mass element, which acts as a limiter for the radial displacement of the mass element 202. More specifically, in a preferred embodiment, the abutment portion is configured to stop radial displacement by interacting with a corresponding portion of the column element 207 of the mass element 207. Alternatively, the abutment portion may be configured to interact with different portions of the mass element to limit the final position of its radial displacement.

[0095] By considering the above figures, it can be seen that the bend 301 defines a number of pressure angles, such as 401, 402 and 403, which are generally pressure angles defined between the direction of the variable axial load and the direction of the load exchanged between the rolling element 205 and the thrust surface 204.

[0096] These pressure angles 401, 402, and 403 change, increasing as the object moves toward the outermost position. In other words, the bend 301 has an increased slope toward the outermost position of the mass element 202 in the centrifugal tablet assembly 200, which increases the pressure angles that affect the axial and radial distribution of the load generated by the mass element 202.

[0097] Generally speaking, it can be said that the bend 301 is therefore configured to provide a stable correlation between the rotational speed of the clutch 100 and the variable axial load acting on the plate 103.

[0098] Figure 10 A three-dimensional view of the fixed hub 101, the movable hub 102, and the insert plate 103 is shown, with a portion of them removed in the figure to allow observation of the interior of the clutch 100.

[0099] The fixed hub 101 includes a first sliding element 501, and the movable hub 102 includes a second sliding element 502. The first sliding element 501 and the second sliding element 502 are configured to engage with each other and slide against each other when subjected to a torque acting on the clutch 100, so as to at least partially change the variable axial load acting on the plate 103.

[0100] Figure 11 A three-dimensional view of the fixed hub 101 and the movable hub 102, which are detachable from each other, is shown to further illustrate the operation of the first sliding element 501 and the second sliding element 502.

[0101] The first sliding element 501 and the second sliding element 502 include their respective first sliding surfaces 510 for traction torque. The first sliding surfaces 510 are inclined according to a first helix and configured to engage with each other when the fixed hub 101 is subjected to traction torque, so that the first sliding element 501 slides on the second sliding element 502 respectively and the movable hub 102 is brought closer to the fixed hub 101, thereby increasing the variable axial load on the plate 103.

[0102] The first sliding element 501 and the second sliding element 502 further include corresponding second sliding surfaces 520 for the reverse torque. The second sliding surfaces 520 are inclined according to a second helix that is opposite to the first helix and are configured to engage with each other when the fixed hub 101 is subjected to the reverse torque (i.e., opposite to the traction torque) so that the first sliding element 501 slides on the second sliding element 502 to bring the movable hub 102 closer to the fixed hub 101, thereby increasing the variable axial load acting on the plate 103.

[0103] It should be noted that, advantageously, the effects of sliding elements 501 and 502 on the axial load acting on tablet 103 are combined synergistically with the effects of the centrifugal tableting assembly 200 described above.

[0104] Because the first tilting helix of the first sliding surface 510 used for traction torque and the second tilting helix of the second sliding surface 520 used for reverse torque have opposite rotations, the sliding surfaces are tilted at two opposite angles relative to the reference axial direction of the axis of the clutch 100.

[0105] The movable hub 102 further includes a crown-shaped draw element 530, and a plurality of plates 103 are assembled around the draw element 530. Specifically, the draw element 530 includes an outer surface shaped to engage with internal teeth on the driven plates (preferably all driven plates) of the plurality of plates 103. In particular, the draw element 530 has a plurality of grooves parallel to each other in the axial direction. Accommodating all driven plates in the draw element 530 provides greater modulusability and more efficient torque transmission for the clutch 100. In fact, the precaution of accommodating all driven plates in the crown-shaped draw element 530 allows operation using sliding surfaces 510 or 520 with higher pitch, thereby providing the benefit of better modulusability of the clutch 100 during engagement.

[0106] Preferably, the second sliding element 502 of the movable hub 102 is adjacent to the inner surface of the stretching element 503, and preferably, the second sliding element 502 is substantially a triangular or trapezoidal protrusion.

[0107] Advantageously, this achieves better lubrication of the components inside the clutch, resulting in improved cooling and reduced wear.

[0108] The first sliding element 501 of the fixed hub is a recess with an opening at its top. When the movable hub 102 is assembled on the fixed hub 101, these openings are configured to allow the second sliding element 502 to pass through. Preferably, the first sliding element 501 is a generally triangular or trapezoidal recess.

[0109] As described, the first sliding surface 510 is inclined relative to the axial direction of the clutch 100 according to a first angle, and the second sliding surface 520 is inclined relative to the axial direction according to a second angle, wherein the second angle has an inclination opposite to the first angle.

[0110] Therefore, the first sliding surface 510 and the second sliding surface 520 are configured to provide engine braking when the fixed hub 101 is subjected to a reverse torque, which can be generated by the vehicle's wheels, thereby increasing the axial load acting on the plate 103 to increase the engine braking torque that can be absorbed by the vehicle's engine.

[0111] This "engine braking" is a state in which delayed traction within the engine is used to slow the vehicle, rather than using external braking mechanisms such as discs, drums, or similar braking systems. "Engine braking" occurs particularly in gasoline engines, especially four-stroke engines, where the throttle is released while the gear and clutch are engaged.

[0112] Advantageously, the second sliding surface 520 is configured to generate axial loads under “electric motor operation” conditions, particularly under engine braking conditions, thereby allowing the use of engine braking, especially downhill braking, and for cruise when engaging a high gear ratio at low engine speeds.

[0113] Due to the first sliding surface 510, by acceleration (i.e., providing traction torque to the clutch), the movable hub 102 and the fixed hub 101 tend to "close" with each other, thereby increasing the axial load acting on the tablet assembly 103, which is added to the axial load generated by the centrifugal tableting assembly 200 described above.

[0114] In this way, a greater torque can be transmitted through clutch 100 when the vehicle is accelerating.

[0115] Even during release, i.e., during the provision of reverse torque to clutch 100, the movable hub 102 and the fixed hub 101 again tend to "close" with each other under engine braking conditions, thereby increasing the axial load acting on the plate assembly 103. At this time, the second sliding surfaces 520 cause them to compensate for the reduction in the axial load acting on the plate 103, and the aforementioned centrifugal plate assembly 200 will tend to close as the rotational speed decreases.

[0116] In this way, it is advantageous to achieve an additional closing effect on the clutch plate under both release and engine braking conditions, while maintaining automatic operation of the centrifugal clutch disengagement when the vehicle approaches a stop, even when the engine is idling and there is virtually no engine braking.

[0117] In one embodiment, the angle between the second sliding surfaces 520 for the counter-torque has an inclination equal to the first angle of the sliding surface 510 for the traction torque, such that the pitch of the first helix corresponds to the pitch of the second helix. In this embodiment, the same characteristic curve between engine speed and maximum transmittable torque occurs under both acceleration conditions (driving torque, i.e., stable engine speed for ascending or traveling on a horizontal surface) and engine braking conditions (counter-torque, i.e., decreasing engine speed for traveling on a horizontal surface).

[0118] In an alternative preferred embodiment, the second angle (i.e., one of the sliding surfaces 520 for the reverse torque) has a smaller inclination than the first angle (i.e., one of the sliding surfaces 510 for the traction torque), such that the pitch of the second helix is ​​greater than that of the first helix. In this alternative embodiment, different characteristic curves appear between engine speed and maximum transmittable torque: under acceleration conditions, there is an effect that hubs 101 and 102 approach each other, which is more pronounced than under engine braking conditions, in order to contribute to less aggressive clutch performance at low engine rpm and high gear conditions.

[0119] Figure 12 A cross-sectional view of another embodiment 100' of the clutch according to the present invention is shown.

[0120] The centrifugal tableting assembly 200 further includes a plurality of interface elements 213 between the respective pivot 203 and the mass carrier 201.

[0121] As the mass element 202 moves by rotating about the pivot 203, these interface elements 213 are configured to locally reduce friction and / or wear. This is particularly effective in the case of the mass carrier 201 made of cast aluminum.

[0122] The centrifugal tableting assembly 200 further includes at least one overtravel spring 220 inserted between the cover of the clutch 100' and the mass carrier 201. The at least one overtravel spring 220 is configured to partially offset the variable axial load when a load threshold is reached.

[0123] Figure 13 A three-dimensional view of an embodiment of the overtravel spring 220 according to the present invention is shown.

[0124] In this embodiment, at least one overtravel spring 220 is Bainstein-shaped and includes an external shape, wherein cutouts 221 are configured to engage with corresponding protrusions of mass carriers 201 at a plurality of mass elements 202.

[0125] In one variation, at least one overtravel spring may be provided by one or more small wave springs of smaller diameter.

[0126] In light of the description provided herein, those skilled in the art can design further modifications and variations to meet possible and specific needs. Therefore, the embodiments described herein should be understood as illustrative and non-limiting examples of the invention.

Claims

1. A clutch, the clutch comprising: Fixed hub (101), movable hub (102), and multiple pieces (103) disposed between the fixed hub (101) and the movable hub (102). The fixed hub (101) and the movable hub (102) are configured to rotate together and are further configured to slide axially, moving away from or towards each other, respectively, to transmit variable axial loads on the plurality of plates (103) and selectively transmit torque acting on the clutch. The clutch further includes a centrifugal pressing assembly (200) to at least partially control the variable axial load, the centrifugal pressing assembly (200) comprising: - A mass carrier (201) is configured to rotate together with the clutch; - Multiple mass elements (202) that are radially movable in the centrifugal tablet assembly (200), wherein each mass element (202) includes a pivot (203) connected to the mass carrier (201) for displacement toward an external position under centrifugal effect; In the case of displacement under centrifugal effect, the plurality of mass elements (202) are further configured to apply axial thrust on the thrust surface (204) of the centrifugal tablet assembly (200) in order to bring the movable hub (102) closer to the fixed hub (101) and increase the variable axial load. The clutch is characterized in that each mass element (202) includes at least one corresponding rolling element (205) in contact with the thrust surface (204). Furthermore, the thrust surface (204) includes an inclined profile that protrudes toward the external position, the inclined profile being configured to generate the axial thrust during the displacement under centrifugal effect, thereby increasing the variable axial load.

2. The clutch according to claim 1, wherein, The inclined profile includes a curved portion (301) having a slope that increases toward the external position.

3. The clutch according to claim 2, wherein, The bending portion (301) defines a plurality of pressure angles (401, 402, 403), which are defined between the direction of the variable axial load and the direction of the exchange load between the corresponding rolling element (205) and the thrust surface (204), wherein the pressure angles (401, 402, 403) vary by increasing toward the external position.

4. The clutch according to claim 3, wherein, The bend (301) is configured to provide a stable correlation between the rotational speed of the clutch and the variable axial load.

5. The clutch according to any one of claims 1 to 4, wherein, The fixed hub (101) includes a first sliding element (501), and the movable hub includes a second sliding element (502), the first sliding element (501) and the second sliding element (502) being configured to engage with each other and slide against each other when subjected to a torque acting on the clutch, so as to at least partially change the variable axial load.

6. The clutch according to claim 5, wherein, The first sliding element (501) and the second sliding element (502) include corresponding first sliding surfaces (510) for traction torque, the first sliding surfaces (510) being inclined according to a first helix and configured to match when the fixed hub (101) is subjected to traction torque, so that the first sliding element (501) slides on the second sliding element (502) respectively, so that the movable hub (102) is closer to the fixed hub (101), thereby increasing the variable axial load on the plurality of plates (103).

7. The clutch according to claim 6, wherein, The first sliding element (501) and the second sliding element (502) further include corresponding second sliding surfaces (520) for a counter-torque, the second sliding surfaces (520) being inclined according to a second helix that is opposite to the first helix and configured to match when the fixed hub (101) is subjected to a counter-torque that is opposite to the traction torque, so as to allow the first sliding element (501) to slide on the second sliding element (502) respectively, so as to bring the movable hub (102) closer to the fixed hub, thereby increasing the variable axial load on the plurality of plates (103).

8. The clutch according to claim 7, wherein, The movable hub (102) further includes a crown-shaped drawing element (530), around which the plurality of plates (103) are assembled. The drawing element (530) includes an outer surface shaped to engage with the internal teeth of the driven piece among the plurality of pieces (103). The second sliding element (502) of the movable hub (102) is adjacent to the inner surface of the stretching element (530), and the second sliding element (502) is a generally triangular or trapezoidal protrusion.

9. The clutch according to claim 8, wherein, The first sliding element (501) of the fixed hub (101) is a recess with an opening on its top, the opening being configured to allow passage of the second sliding element (502) when the movable hub (102) is assembled on the fixed hub (101), the first sliding element (501) being substantially trapezoidal.

10. The clutch according to any one of claims 1 to 4, wherein, The centrifugal tableting assembly (200) further includes a plurality of interface elements (213) between the respective pivot (203) and the mass carrier (201), the plurality of interface elements (213) being configured to locally reduce friction and / or wear.

11. The clutch according to any one of claims 1 to 4, further comprising a housing (11) outside the fixed hub (101) and rotatable about a rotation axis; wherein, The fixed hub (101) is configured to be connected to a shaft (10) coaxial with the axis of rotation; and wherein the movable hub (102) is axially mounted on the fixed hub (101) along the axis of rotation.

12. The clutch according to any one of claims 1 to 4, wherein, Each of the mass elements (202) includes a body (206) including at least one of the rolling elements (205) and further including a substantially elongated column element (207) that connects the pivot (203) to the body (206) and is configured to extend the lever arm in the displacement under centrifugal effect.

13. The clutch according to claim 12, wherein, The mass element (202) has a center of mass within the body (206), wherein the column element (207) defines a pivot (203) which is radially outward relative to the axis of rotation than the center of mass.

14. The clutch according to any one of claims 1 to 4, wherein, The centrifugal tablet assembly (200) further includes at least one overtravel spring (220) inserted between the cover of the clutch and the mass carrier (201), the at least one overtravel spring (220) being configured to partially counteract the variable axial load when a threshold is reached.

15. The clutch according to claim 14, wherein, The at least one overtravel spring (220) includes an external shape with a cutout (221) configured to engage with corresponding protrusions of the mass carrier at the plurality of mass elements (202).

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