Multi-plate wet clutch

Abstract

To provide a multi-plate wet clutch having an internal shaft conduit for a coolant.SOLUTION: A wet clutch 10 has a clutch hub 16, a clutch basket 18, a clutch pack 20 operably connected to the clutch hub 16 and the clutch basket 18; and a collar 34. The wet clutch 10 further has a plurality of independent clutch conduits 48, each of which has a collar portion 52 and a hub portion 50. The collar portion 52 has an inflow port 54 which receives a coolant. The hub portion 50 has one or more outflow ports for discharging the coolant on the clutch pack 20. The wet clutch 10 further has a plurality of valves 28, each of which is operably connected to a single clutch conduit and configured to control the flow of the coolant through the clutch conduit. The actuator 22 is supported by the collar 34 and configured to simultaneously engage the clutch pack 20 and operate the plurality of valves 28.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The proposed technology generally relates to wet clutches for on-road vehicles, and more specifically to multi-plate wet clutches for high-performance applications.

Background Art

[0002] Depending on the application, the dimensions of single-plate clutches are too large, so a smaller clutch is required to transfer the necessary torque. This can be achieved by a multi-plate clutch that allows the diameter to be reduced while keeping the overall frictional force constant. Multi-plate clutches are a well-established technology. In on-road vehicles, multi-plate clutches are typically found in motorcycles and high-performance automobiles. A multi-plate clutch typically has a plurality of driving parts with a plurality of driven parts sandwiched therebetween, which are typically assembled in a clutch pack. It is necessary to further reduce the dimensions of the clutch while improving efficiency, or at least maintain the current dimensions.

[0003] The friction part or the driving and driven parts of a dry clutch are not exposed to a cooling lubricating liquid and rely only on mechanical friction for connection. In a wet clutch, the friction part is typically immersed in a cooling and lubricating liquid that allows for smoother performance and a longer lifespan. In some applications, viscosity may occur due to the tension within the clutch pack of a wet clutch that does not change even over a long period, resulting in a potential loss of efficiency. Such wet clutches are typically designed to be disengaged when not starting and engaged when starting actively. Therefore, a multi-plate wet clutch is required that relaxes the viscous tension when the clutch is disengaged.

Summary of the Invention

Problems to be Solved by the Invention

[0004] The object of the proposed technology is to improve the efficiency of a multi-plate wet clutch and reduce its overall dimensions. Another object of the proposed technology is to improve the cooling of the clutch and reduce the tensile viscosity when the clutch connection is released.

[0005] In a first aspect of the proposed technology, a multi-plate wet clutch provided on a shaft having an internal shaft conduit for a coolant is provided. The wet clutch includes a clutch hub provided on the shaft, a clutch basket supported so as to rotate with respect to the shaft, a clutch pack operably connecting the clutch hub and the clutch basket, and a collar or a front end portion provided on the shaft. The collar is juxtaposed to the clutch hub. The wet clutch further includes a plurality of independent clutch conduits. Each of the plurality of independent clutch conduits has a collar portion formed by the collar and a hub portion formed by the clutch hub. The collar portion has an inlet for receiving the coolant. The hub portion is coupled to the collar portion and has one or more outlets for discharging the coolant to the clutch pack. The wet clutch further includes a plurality of valves each operably connected to a single clutch conduit to control the flow of the coolant through the clutch conduit, and an actuator supported by the collar and connected to the clutch pack while operating the plurality of valves.

[0006] With the plurality of clutch conduits, the wet clutch can have a compact configuration. In addition, the fact that the actuator is connected to the clutch pack and operates the plurality of valves means controlling both the operation or connection and disconnection and the cooling of the clutch pack. This engagement function also enables a more compact configuration.

[0007] In the present application, the collar is construed as being ring-shaped, and a wet clutch having an actuator supported by, for example, a sealing housing or a case, is made possible to have a smaller configuration as compared with the collar provided on the shaft and the actuator supported by the collar. The proposed technology also enables the supply of a coolant having the highest effect inside the clutch pack.

[0008] The clutch pack is construed as a multi-plate clutch pack having a plurality of laminated inner plates and outer plates, or a plurality of laminated driving plates and driven plates.

[0009] The actuator may be a single actuator. This means that there is only one actuator that operates the clutch pack and the plurality of valves. The fact that a single actuator can serve this function further contributes to a smaller configuration.

[0010] The clutch hub may be firmly attached directly to the shaft, for example, by splines. The collar may be firmly attached to the clutch hub, for example, by bolts. Alternatively, instead thereof, the collar may be firmly attached directly to the shaft. In this way, the clutch hub and the collar can be fixed to the shaft in the rotational direction and the axial direction, that is, the longitudinal direction. When the clutch hub is installed, the fact that the clutch hub and the collar are fixed to the shaft in the rotational direction and the axial direction means that the clutch hub and the collar cannot rotate relative to the shaft and cannot move longitudinally relative to the shaft. The fact that the clutch basket is supported so as to rotate relative to the shaft means that the clutch basket can rotate relative to the shaft if not prevented by the clutch pack. The clutch basket may be fixed axially to the shaft, for example, by a rotary bearing. This means that when the wet clutch is provided on the shaft, the wet clutch cannot move axially relative to the shaft, and only the pair of the clutch basket and the clutch pack connected to the clutch basket can rotate relative to the shaft.

[0011] The clutch hub may be concentric with the shaft. Similarly, the clutch basket may be concentric with the shaft. When the wet clutch is provided on the shaft, the shaft is understood to penetrate the clutch basket and the clutch hub. In other words, the wet clutch enables the shaft to penetrate the entire length of the axis of the shaft, that is, to extend along the entire length of the axis of the shaft. This means that the wet clutch forms a through-hole for receiving the shaft.

[0012] The clutch hub may constitute an integrated body manufactured from a single material member. Similarly, the collar may also constitute an integrated body manufactured from a single material member. The clutch hub may form a through hole for receiving the shaft. Similarly, the collar may also form a through hole for receiving the shaft.

[0013] The coolant may be a liquid. The coolant may further be a lubricant within the wet clutch or in an external device - for example, the gears of a gearbox - or may have the function of a lubricant. The coolant may be oil-based.

[0014] The wet clutch may be a pull clutch. The actuator may be configured to connect the clutch pack when activated. This means that the wet clutch must be actively connected or locked. When the actuator stops operating, the clutch pack and thus the wet clutch are disengaged, i.e., opened.

[0015] The plurality of independent clutch conduits may have 10 or more clutch conduits. Each of the hub portions of the plurality of independent clutch conduits may be aligned and extended with respect to the shaft, i.e., may extend parallel to the shaft. Each of the hub portions may have a cylindrical portion. This means that the cylindrical portion is formed like a cylinder. The cylindrical portion may have a circular cross-section. The cylindrical portion may have an axis parallel to the shaft or to the axis of the shaft. All of the cylindrical portions of the hub portions may have parallel cylindrical axes. The features specified here enable a compact conduit configuration. As a result, a smaller wet clutch is possible.

[0016] The color may form a through hole for receiving the shaft. The through hole has a peripheral inner wall portion facing the shaft. The color forms a peripheral groove or channel in the inner wall portion for receiving the coolant from the conduit of the shaft. The inlet of each of the clutch conduits of the collar portion is connected to the groove. For example, the conduit of the shaft may have a single outlet, and when the wet clutch is installed, the peripheral groove may be provided at the single outlet to communicate with the single outlet. The inner wall portion facing the shaft may be at the same height as the shaft and may be configured to prevent leakage of the coolant between the color and the shaft.

[0017] The collar portions of the clutch conduits may be evenly distributed around the shaft. Similarly, the hub portions of the clutch conduits may also be evenly distributed around the shaft. The distribution around the shaft is understood as an angular distribution with respect to the rotation axis of the shaft. For example, when there are 12 collar portions, the centers of adjacent collar portions are 30° apart with respect to the rotation axis of the shaft.

[0018] The plurality of clutch conduits and the groove may operably connect the conduit of the shaft and the outlet, and may form a (part of a) conduit arrangement that enables the coolant to flow between the conduit of the shaft and the outlet. Thus, the conduit arrangement forms a manifold for distributing the coolant.

[0019] Each of the clutch conduits or hub portions may have a plurality of outlets distributed axially with respect to the clutch hub. That is, this means that the outlets are distributed axially with respect to the shaft. Alternatively, instead, each of the clutch conduits or hub portions may have a single outlet extending axially with respect to the clutch hub. This enables the axial distribution of the coolant. As a result, a clutch pack with a large number of plates and a short diameter is possible. Thus, the clutch pack contributes to a more efficient and compact wet clutch.

[0020] The clutch hub and the clutch pack may form a spline joint including a plurality of axially extending ridges and grooves within the clutch hub, or may be connected by the spline joint. Thus, one or more outlets of each of the clutch conduits may be provided at the bottom of a single groove. In other words, the spline joint may have a plurality of male splines within the clutch hub, and one or more outlets of each of the clutch conduits may be provided between two adjacent male splines. The number of ridges or male splines may be an integer multiple of the number of clutch conduits. For example, the number of clutch conduits may be 15, and the number of male splines may be 45 corresponding to three times the number of clutch conduits. The plurality of axially extending ridges and grooves may form male splines cooperating with female splines formed by the clutch pack. The clutch pack may have, at a given torque transmitted by the shaft, (a) a disengaged state in which the clutch hub and the clutch basket are unlocked and can rotate at different speeds, (b) a slipping state in which the clutch hub and the clutch basket are partially locked together, i.e., are partially connected by kinetic friction and can rotate at different speeds, and (c) an engaged state in which the clutch hub and the clutch basket are locked together, i.e., are fully connected by static friction and rotate at the same speed.

[0021] When the clutch hub and the clutch basket are not locked, it is understood that torque is not mechanically transferred between the clutch hub and the clutch basket. Torque transfer occurring only by the fluid coupling of the coolant is not regarded as mechanical torque transfer in the present application. That the clutch hub and the clutch basket are partially locked means that there is a slip mechanical coupling between the clutch hub and the clutch basket. The slipping state is understood to include a state of partial connection. That the clutch hub and the clutch basket are locked and integrated means that there is no slip mechanical coupling between the clutch hub and the clutch basket.

[0022] The clutch pack may be concentric with the clutch hub, that is, concentric with the shaft. The clutch basket may be concentric with the clutch pack, that is, concentric with the clutch hub. The clutch pack may have an annular shape and extend in both the radial direction and the axial direction with respect to the clutch hub, that is, with respect to the shaft.

[0023] The clutch pack may include a plurality of inner plates attached to, that is, connected to, the clutch hub, and a plurality of outer plates attached to, that is, connected to, the clutch basket. The inner plates are axially movable with respect to the clutch hub and are fixed in the angular direction. The outer plates are axially movable with respect to the clutch basket and are fixed in the angular direction. This means that the clutch hub constitutes an inner plate carrier and the clutch basket constitutes an outer plate carrier.

[0024] Alternatively, the inner plates and the outer plates may be provided in the clutch pack. In the connected state, there is no mechanical friction between the inner plates and the outer plates. In the slip mode, there is kinetic friction between the inner plates and the outer plates. In the disengaged state, there is static friction between the inner plates and the outer plates.

[0025] The actuator may be configured to axially compress the clutch pack. When the clutch pack is axially compressed, it may change from the disconnected state (a), through the slipping state (b), to the connected state (c). The clutch pack may form a plurality of radially extending channels for the coolant that exist between the inner plate and the outer plate or pass through the clutch pack when in the connected state. The channels may be formed in the inner plate and may define a square or rectangular grid pattern. The radially extending channels contribute to efficient cooling of the clutch pack.

[0026] The clutch hub may have a plurality of male splines. Each of the plurality of inner plates may have a plurality of female splines that cooperate with the plurality of male splines of the clutch hub. The clutch basket may have a plurality of female splines. Each of the plurality of outer plates may have a plurality of male splines that cooperate with the plurality of female splines of the clutch basket.

[0027] The valve may (i) prevent or restrict the flow of coolant when the clutch pack is in the disconnected state, (ii) allow the flow of coolant when the clutch pack is in the slipping state, and may allow the flow of coolant when the clutch pack is in the connected state. The flow of coolant when the clutch pack is in the connected state may be greater than the flow of coolant when the clutch pack is in the slipping state. For example, the flow of coolant when in the slipping state may be in the range of 70% - 100% or 90% - 100% of the flow in the connected state.

[0028] The wet clutch may further include an annular pressure plate that is concentric with the shaft and provided between the actuator and the clutch pack. The pressure plate may be connected to the clutch pack and may form a part of each of the valves. For each of the valves, the collar may form a valve seat at a connection portion, i.e., a connection part, between the hub portion and the collar portion of the clutch conduit to which the valve is connected. The seat may be a hard seat integrated with the collar. This means that there is no elastomeric gasket for sealing. The pressure plate may be disk-shaped and / or may have rotational symmetry with respect to the shaft. The pressure plate may have a central hole. The pressure plate may have or form a plurality of protrusions. Each of the plurality of protrusions extends radially inward within or with respect to the central hole. Each protrusion of the pressure plate may form a valve member or a valve disk of a single valve of the plurality of valves. The protrusion may contact the valve seat of the valve or may seal against the valve seat of the valve when the wet clutch is in the connected state. In the connected state, the wet clutch may provide a gap between the protrusion and the valve seat. Thereby, the lubricant can flow through the protrusion and into the hub portion.

[0029] The pressure plate may form a part of the actuator or may be integrated with the actuator. In the slipping state and the connected state, the clutch pack may be axially loaded by the pressure plate.

[0030] The wet clutch (10) may further include a plurality of springs individually provided in the hub portion of the plurality of clutch conduits. Each of the plurality of springs is connected to, i.e., biases, the pressure plate. This means that there is a spring in the hub portion of each of the clutch conduits. The spring is biased, i.e., pushed and released, so that the pressure plate moves toward the actuator or the collar.

[0031] When the hub portion has a cylindrical portion, the spring may be provided within the cylindrical portion of the hub portion. Each of the springs may be connected to the protruding portion of the pressure plate. When the protruding portion constitutes a part of the valve, this means that the spring is coupled and acts to close the valve. Each of the springs may be a compression coil spring and may be oriented to compress and extend parallel to the shaft.

[0032] The pressure plate or the protruding portion may fix the collar portion of the clutch conduit when the clutch pack or the wet clutch is in the disconnected state. In this way, it is possible to prevent the coolant from flowing through the clutch conduit and reaching the clutch pack.

[0033] The actuator may include an annular recess formed by the collar and concentric with the shaft, and an annular piston provided in the recess and movable axially with respect to the shaft. The annular recess may face the clutch pack or the pressure plate, or may open in the direction of the clutch pack or the pressure plate. The annular piston may be connected or in contact with the annular pressure plate. In the slipping state and the connected state, the annular piston applies a load to the pressure plate, that is, pushes against the pressure plate. The plurality of springs may push the pressure plate toward the annular piston, that is, bias the pressure plate against the annular piston.

[0034] The shaft may have a further internal shaft conduit for the working fluid. The actuator may be configured to be operably connected to the further internal shaft conduit. More precisely, the annular recess may be configured to be connected to the further internal shaft conduit, for example by a connecting conduit, i.e., to exchange fluid with the further internal shaft conduit. When installed, this means that the actuator is started by an increase in the pressure of the working fluid, causing the ring-shaped piston to move towards the clutch pack or the pressure plate and to engage with the wet clutch.

[0035] The wet clutch may further comprise a flange or a rear end portion configured to be provided on the shaft and extending radially. The flange is juxtaposed to the clutch hub. The clutch pack is provided between the flange and the collar. The clutch pack is pushed against the flange when connected by the actuator. The flange may be firmly attached to the clutch hub, for example by bolts. Alternatively, instead, the flange may be firmly attached directly to the shaft. In either case, the clutch hub and the collar may be fixed relative to the shaft in the rotational direction and the axial direction. The flange is understood to extend outwardly or laterally relative to the shaft. The flange has the function of an adjacent plate, i.e., an end plate. The clutch pack is pushed by the actuator against the adjacent plate. In the slipping state and the engaged state, the clutch pack is axially loaded by the pressure plate and the flange. The flange may be concentric with the shaft. The flange may have an annular shape. The flange enables the configuration of the wet clutch to be made smaller.

[0036] The clutch basket may have a cylindrical shape or may be ring-shaped. This means that the radial extension of the clutch basket is restricted and the clutch basket does not constitute an end plate extending in the radial direction. The clutch basket is provided with or forms a plurality of openings that allow the coolant to exit radially outward from the wet clutch. This means that the wet clutch is not sealed and the coolant is not contained within the wet clutch. Thus, a circulation system for the coolant that enables a smaller configuration is required inside the wet clutch. Instead, the coolant may be circulated by an external system. In addition, this enables the wet clutch to be in a state without coolant when the wet clutch or the clutch pack is not connected. In addition or alternatively, a gap through which the coolant exits the wet clutch may exist between the clutch pack and the collar.

[0037] The above object is also achieved by a second aspect of the proposed technique in which a gear assembly is provided on a shaft having an internal shaft conduit for a coolant. The gear assembly includes a gear wheel or gear rotatably supported with respect to the shaft, and a wet clutch according to the first aspect of the proposed technique. The wet clutch is operably connected to the inner shaft conduit and provided on the shaft. The clutch basket of the wet clutch is attached to or provided on the gear wheel. The shaft may have a further internal shaft conduit for the working fluid. The actuator may be configured to be operably connected to the further internal shaft conduit.

[0038] In the present application, being operably connected to the internal shaft conduit is understood to include the inlet of the collar portion of the individual clutch conduits of the wet clutch being coupled to or in fluid communication with the internal shaft conduit. The clutch basket is understood to be fixed in the rotational direction to the gear wheel.

[0039] The gear wheel and the wet clutch may be concentric with respect to the shaft. The term "gear wheel" is understood not to include a sprocket or sprocket wheel that is widely used for engagement with a chain, belt, etc. The gear wheel may have a maximum radius that is 2 to 7 times larger than the width at the maximum radius. The maximum radius is defined as the radius of the outer circle defined by the gear or the apex of the teeth of the gear, and the width may be understood to be the width of the gear or the teeth.

[0040] The gear wheel may have or constitute a flange that extends axially and is concentric with respect to the shaft. The clutch basket and the flange overlap. The clutch basket is attached to the flange. The clutch basket and the flange may have a conforming shape at the overlapping portion. The outside of the flange may conform to the inside of the clutch basket at the overlapping portion.

[0041] The gear assembly as a whole may form a through-hole for receiving the shaft. The gear assembly may further include a radius spacer configured to be fixed in the rotational direction with respect to the shaft, and a radius rotary bearing having an inner race attached to the radius spacer and an outer race attached to the gear wheel. The radius spacer has the effect of increasing the radius of the rotary bearing. As a result, a larger radial load becomes possible on the gear assembly. In addition, the radius spacer reduces the mass rotating with respect to the shaft. As a result, it becomes possible to speed up the response when connecting to the wet clutch.

[0042] The gear wheel has a cylindrical inner wall and a central through-hole or bore, and the outer race is understood to fit or be attached to the inner wall of the through-hole. The radius spacer may have an annular hollow body. The body may be hollow or may be partially hollow. The radius spacer may be attached to the clutch hub or may be provided on the clutch hub. Thus, the clutch hub may be configured to be rigidly directly attached to the shaft and provided on the shaft as described above. In this way, the radius spacer is configured to be fixed in the rotational direction with respect to the shaft.

[0043] The above object is also achieved by a third aspect of the proposed technique provided with a shaft assembly. The shaft assembly includes a shaft having an internal shaft conduit for a coolant, and a gear assembly according to the second aspect of the proposed technique. The gear assembly is operably connected to the internal shaft conduit and provided on the shaft.

[0044] In the present application, being operably connected to the internal shaft conduit is understood to include that the wet clutch of the gear assembly is operably connected to the internal shaft conduit. The shaft may have a further internal shaft conduit for a working fluid. The actuator of the gear assembly or the wet clutch may be configured to be operably connected to the further internal shaft conduit.

Brief Description of the Drawings

[0045] It is clear that the above and other features and advantages of the proposed technique can be more fully understood from the following detailed description of the preferred embodiment of the proposed technique together with the accompanying drawings.

Figure 1

Figure 2

Figure 3

Figure 4

DETAILED DESCRIPTION OF THE INVENTION

[0046] FIG. 1 schematically represents a shaft assembly 6 having a shaft 12 with an internal shaft conduit 14 intended to carry coolant and lubricant together. The shaft assembly 6 also has a gear assembly 8 provided on the shaft 12 and connected to the internal shaft conduit 14. The gear assembly 8 as a whole forms a through hole 68 for receiving the shaft 12. The shaft 12 passes through the gear assembly 8 through the through hole 68.

[0047] As can be seen from FIG. 2, the gear assembly 8 has a gear wheel 80 rotatably supported with respect to the shaft 12. The gear assembly 8 also has a wet clutch 10 operably connected to the internal shaft conduit 14 and provided on the shaft 12.

[0048] The gear wheel 80 and the wet clutch 10 are concentric with respect to the shaft 12. The gear wheel 80 has an axially extending flange 82 that is concentric with respect to the shaft 12. The clutch basket 18 and the flange 82 overlap at the flange 82. The outer side of the flange 82 fits inside the clutch basket 18 at the overlapping portion. The clutch basket 18 is attached to the flange 82, that is, to the gear wheel 80.

[0049] The wet clutch 10 is a multi-plate clutch. The shaft 12 passes through the entire wet clutch 10. The wet clutch 10 has a clutch hub 16 that is fixed radially with respect to the shaft 12 by splines and is provided on the shaft 12. The wet clutch 10 further has a clutch basket 18 that is rotatably supported with respect to the shaft 12, and a clutch pack 20 that connects the clutch hub 16 and the clutch basket 18. The wet clutch 10 also has a collar 34 that is connected to the clutch hub 16 by bolts and juxtaposed. In this way, the collar 34 is fixed in the rotational direction with respect to the shaft 12 and is provided on the shaft 12.

[0050] The clutch hub 16 and the clutch basket 18 are concentric with respect to the shaft 12. The clutch hub 16 forms a through hole 62. The collar 34 forms another through hole 64. This means that the clutch hub 10 as a whole forms a through hole 66 for receiving the shaft 12.

[0051] The gear assembly 8 has a radius spacer 84 that is fixed in the rotational direction with respect to the clutch hub 16 by bolts. Thus, the radius spacer 84 is also fixed in the rotational direction with respect to the shaft 12. The gear assembly 8 further has a radius rotary bearing 86 that includes an inner race attached to the radius spacer 84 and an outer race attached to the gear wheel 80. The gear wheel 80 has a central through hole with a cylindrical inner wall. The outer race fits and connects to the inner wall of the through hole. The radius spacer 84 has an annular partial hollow body.

[0052] A clamp (not shown) is provided on the shaft 12 on either side of the gear assembly 8. Thereby, the wet clutch 10, that is, the clutch hub 16, the clutch basket 18, and the collar 34 are fixed axially with respect to the shaft 12.

[0053] The clutch hub 16 was manufactured as a single-piece member. Similarly, the collar 34 was also manufactured as a single-piece member. This means that each member independently constitutes an integrated body.

[0054] The wet clutch 10 has a number of independent clutch conduits 48 - more precisely 15 clutch conduits 48. Each has a collar portion 52 formed by the collar 34 and a hub portion 50 formed by the clutch hub 16. The collar portion 52 has an inlet 54 through which coolant can be received. The hub portion 50 is coupled to the collar portion 52 and has three outlets through which the coolant can be released in the clutch pack 20. The outlets 24 are distributed axially with respect to the clutch hub 16. This means that the outlets 24 are distributed longitudinally with respect to the shaft 12.

[0055] The hub portion 50 of each clutch conduit 48 extends in alignment with the shaft 12. As can be seen from FIG. 3, each hub portion 50 has a cylindrical portion 56 having a circular cross-section and an axis parallel to the axis 90 of the shaft 12. This means that all the cylindrical portions 56 have parallel cylindrical axes.

[0056] The through-hole 64 of the collar 34 for receiving the shaft 12 has a peripheral inner wall portion 72 facing the shaft 12. The collar 34 forms a peripheral groove 70 within the inner wall portion 72 capable of receiving coolant from the shaft conduit 14. The inlet 54 of the collar portion 52 of each clutch conduit 48 is connected to the groove 70. The inner wall portion 72 facing the shaft 12 is at the same height as the outer surface of the shaft 12. In this way, the individual clutch conduits 48 form part of a conduit arrangement 26 that connects the shaft conduit 14 to the outlets 24. The conduit arrangement 26 has the function of a manifold by enabling the distribution of coolant from the shaft conduit 14 in the clutch pack 20.

[0057] The collar portions 52 and hub portions 50 of the clutch conduits 48 are evenly distributed around the shaft 12. The collar portions 52 and hub portions 50 are 24° apart with respect to the axis of rotation 90 between adjacent clutch conduits 48.

[0058] The clutch hub 16 has a number of axially extending ridges 44 that form part of a spline joint with the clutch pack 20. The outlet 24 of each clutch conduit 48 is provided between a pair of adjacent ridges 44 - more precisely at the bottom of a single groove between adjacent ridges 44. There are 45 ridges 44 and 15 clutch conduits 48. This means that there are three times as many ridges 44 as clutch conduits 48. The axially extending ridges 44 form male splines 44 that cooperate with female splines 46 formed by the clutch pack 20.

[0059] The clutch pack 20 has three states. In the first state, i.e., the disengaged state, the clutch hub 16 and the clutch basket 18 are not locked and can rotate at different speeds. That is, this means that the gear wheel 80 can rotate freely relative to the shaft 12. In the second state, i.e., the slipping state, the clutch hub 16 and the clutch basket 18 are partially locked together but can rotate at different speeds. This means that part of the torque is transferred from the shaft 12 to the gear wheel 80. In the third state, i.e., the engaged state, the clutch hub 16 and the clutch basket 18 are locked together and rotate at the same speed. This means that all the torque supplied to the shaft 12 is transferred to the gear wheel 80.

[0060] The wet clutch 10 has a number - more precisely 15 - of valves 28. Each valve 28 controls the flow of coolant through a single clutch conduit 48. The wet clutch 10 further has a single actuator supported by a collar 34 and an annular pressure plate 40 that is concentric with the shaft 12. The pressure plate 40 is provided between the actuator 22 and the clutch pack 20 so that it can be connected to the clutch pack 20 when the actuator 22 is activated. In addition, the pressure plate 40 forms part of each valve 28. This means that the pressure plate 40 connects to the clutch pack 20 and simultaneously operates the valves 28.

[0061] When activated, the actuator axially compresses the clutch pack 20, and when the clutch pack 20 is axially compressed, it changes from the disengaged state, through the slipping state, to the engaged state.

[0062] The clutch pack 20 is concentric with the clutch hub 16 and the shaft 12. The clutch basket 18 is concentric with the clutch pack 20, that is, with respect to the clutch hub 16. The clutch pack 20 has an annular shape and extends in both the radial direction and the axial direction with respect to the axis 90 of the shaft.

[0063] The clutch pack 20 has eight inner plates 30 attached to the clutch hub 16 and seven sandwiched outer plates 32 attached to the clutch basket 18. The clutch hub 16 constitutes the carrier of the inner plates. The clutch basket 18 constitutes the carrier of the outer plates. The inner plates 30 are axially movable with respect to the clutch hub 16 and are fixed in the rotational direction with respect to the clutch hub 16. Similarly, the outer plates 32 are axially movable with respect to the clutch basket 18 and are fixed in the rotational direction with respect to the clutch basket 18.

[0064] The inner plates 30 and the outer plates 32 are alternately provided within the clutch pack 20. In the disengaged state, there is no mechanical friction between the inner plates 30 and the outer plates 32. In the slipping state, there is kinetic friction between the inner plates 30 and the outer plates 32. In the engaged state, there is static friction between the inner plates 30 and the outer plates 32.

[0065] The clutch pack 20 forms channels 92 in a square grid pattern on both sides of each inner plate 30. Even if it does not face the radial direction, the square grid on the circular plate means that all of the channels 92 extend to some extent in the radial direction with respect to the shaft 12. Thereby, the coolant can flow radially outward through the clutch pack 20.

[0066] As described above, the clutch hub 16 has a number of outer male splines 44, and the inner plate 30 has the same number of female splines 46 that cooperate with the male splines 44. Similarly, the clutch basket 18 has female splines 76, and each of the outer plates 32 has male splines 78 that cooperate with the female splines 76.

[0067] The valve 28 is constructed to prevent coolant from flowing through the clutch conduit 48 when the clutch pack 20 is in the disengaged state. The valve 28 further enables coolant to flow when the clutch pack 20 is in the slip state and the engaged state. In some embodiments, the coolant flow when the clutch pack 20 is in the engaged state is at most 10 times greater than when the clutch pack 20 is in the disengaged state. This means that there is coolant flow even when the valve 28 is in the closed state.

[0068] The collar 34 forms a valve seat 96 at each joint between the hub portion 50 and the collar portion 52 of the clutch conduit 48. The valve seat 96 is a hard seat integrated with the collar 34.

[0069] The pressure plate 40 is disk-shaped and rotationally symmetric about the axis 90 of the shaft 12 in a plane. As shown in FIG. 4, the pressure plate 40 has a central through hole 94 and forms a number - more precisely 15 - of protrusions 60. Each of the protrusions 60 extends radially inward within the central hole 94. When the wet clutch 10 is in the disengaged state, each of the protrusions 60 constitutes the valve portion of a single valve 28, i.e., the valve disk, and seals against one of the valve seats 96. In the engaged state, the pressure plate 40 is pushed by the actuator 22 such that a gap is formed between the protrusion 60 and the valve seat 96. Thereby, the coolant flow can pass through the protrusion 60 and flow into the hub portion 50. From there, the coolant is discharged through the outlet 24.

[0070] The compression coil spring 58 is provided within the cylindrical portion 56 of each hub portion 50. Each spring 58 is connected to a single protrusion 60 of the pressure plate 40. The spring 58 functions to bias the pressure plate 40 together with respect to the clutch hub 16 and close the valve 28 by pushing the pressure plate toward the actuator 22.

[0071] When the clutch pack 20 or the wet clutch 10 is in the disengaged state, the valve is closed where the protrusion 60 blocks the collar portion 52 of the clutch conduit 48. In this way, it is prevented that the coolant flows through the clutch conduit 48 and reaches the clutch pack 20.

[0072] The actuator 22 has an annular recess 36 formed by the collar 34 and concentric with respect to the axis 90 of the shaft 12. The actuator 22 further has an annular piston 38 provided within the recess 36 and configured to move axially with respect to the shaft 12. The piston 38 is sealed by a gasket 98 that prevents leakage of the working fluid passing through the piston 38.

[0073] The annular piston 38 is connected to the annular pressure plate 40. In the slipping state and the connected state, the piston 38 pushes against the pressure plate 40 and applies an axial load to the pressure plate 40. The plurality of springs 58 provide a reactive force that pushes the pressure plate 40 against the annular piston 38. By the pressure plate 40, the actuator 22 is configured to connect with the clutch pack 20 and simultaneously operate a plurality of valves 28.

[0074] The shaft 12 has a further internal shaft conduit 88 for the working fluid. The annular recess 36 is connected to the further internal shaft conduit 88. The actuator 22 is started by an increase in the pressure of the working fluid. The increase in the pressure of the working fluid moves the annular piston 38 toward the clutch pack 20 and connects it with the wet clutch 10.

[0075] The wet clutch 10 further has a flange 42 that is concentric with the shaft 12 and extends radially and outwardly on the shaft 12. The flange 42 is juxtaposed with the clutch hub 16. The clutch pack 20 is provided between the flange 42 and the collar 34. The flange 42 is attached to the clutch hub 16 by bolts. When the clutch pack 20 is connected by the actuator 22 in the slipping state and the connected state of the wet clutch 10, the clutch pack 20 is pushed against the flange 42.

[0076] As can be seen from FIG. 3, the clutch basket 18 has a cylindrical shape without end plates. The clutch basket 18 has a plurality of openings 74 through which the coolant can exit the wet clutch 10 radially outward with respect to the axis 90 of the shaft 12. There is also a gap between the clutch basket 18 and the collar 34 through which the coolant can exit the wet clutch 10.

Explanation of Reference Numerals

[0077] 6 Shaft assembly 8 Gear assembly 10 Wet clutch 12 Shaft 14 Internal shaft conduit for coolant 16 Clutch hub 18 Clutch basket 20 Clutch pack 22 Actuator 24 Outlet 26 Conduit arrangement 28 Valve 30 Internal plate 32 External plate 34 Collar 36 Annular groove 38 Annular piston 40 Pressure plate 42 Flange 44 Male spline of clutch hub 46 Female spline of internal plate 48 Clutch conduit 50 Hub portion of individual clutch conduits 52 Collar portion of individual clutch conduits 54 Inlet of clutch conduit 56 Cylindrical portion 58 Spring 60 Protrusion of pressure plate 62 Through hole of clutch hub 64 Through hole of collar 66 Through hole of wet clutch 68 Through hole of gear assembly 70 Peripheral groove of collar 72 Inner wall portion of through hole of collar 74 Opening of clutch basket 76 Female spline of clutch basket 78 Male spline of outer plate 80 Gear wheel 82 Flange extending in the axial direction of gear wheel 84 Radial spacer 86 Rotational bearing 88 Further internal shaft conduit for working fluid 90 Shaft axis 92 Channel of internal plate 94 Through hole of pressure plate 96 Valve seat 98 Gasket 100 Gap

Claims

1. A multi-plate wet clutch provided on a shaft having an internal shaft conduit for a coolant, wherein the shaft penetrates through the whole, a clutch hub configured to be provided on the shaft, a clutch basket configured to be rotatably supported with respect to the shaft, a clutch pack operably connected to the clutch hub and the clutch basket, a collar configured to be provided on the shaft so as to be juxtaposed to the clutch hub, a plurality of independent clutch conduits each having a collar portion formed in the collar and having an inlet for receiving the coolant, and a hub portion formed in the clutch hub, coupled to the collar portion, and having one or more outlets for discharging the coolant near the clutch pack, a plurality of valves each operably connected to a single clutch conduit and configured to control the flow of the coolant through the clutch conduit, an actuator supported by the collar, configured to be connected to the clutch pack, and configured to operate the plurality of valves, A multi-plate wet clutch comprising an annular pressure plate that is concentric with the shaft, provided between the actuator and the clutch pack, connected to the clutch pack, and constitutes a part of each of the valves.

2. The wet clutch according to claim 1, wherein each of the hub portions of the clutch conduits extends in a state parallel to the shaft.

3. The collar forms a through hole for receiving the shaft, the through hole has a peripheral inner wall portion facing the shaft, the collar forms a peripheral groove in the inner wall portion for receiving the coolant from the conduit of the shaft, the inlet of each of the collar portions of the clutch conduits is connected to the groove, The wet clutch according to claim 1 or 2.

4. The wet clutch according to any one of claims 1 to 3, wherein each of the clutch conduits has a plurality of outlets distributed axially with respect to the clutch hub.

5. The clutch hub and the clutch pack form a spline joint including a plurality of axially extending ridges and grooves in the clutch hub, one or more outlets of each of the clutch conduits are provided at the bottom of a single groove, The wet clutch according to any one of claims 1 to 4.

6. The clutch pack, (a) A disengaged state in which the clutch hub and the clutch basket are not locked and can rotate at different speeds. (b) A slipping state in which the clutch hub and the clutch basket are partially locked together, i.e., partially connected by kinetic friction and can rotate at different speeds, and (c) An engaged state in which the clutch hub and the clutch basket are locked together, i.e., fully connected by static friction and rotate at the same speed. It has The clutch pack includes a plurality of inner plates attached to the clutch hub and a plurality of outer plates attached to the clutch basket. The actuator is configured to axially compress the clutch pack. When the clutch pack is axially compressed, it changes from the disengaged state through the slipping state to the engaged state. The clutch pack forms a plurality of radially extending channels for the coolant that exist between the inner plate and the outer plate when in the engaged state. The wet clutch according to any one of claims 1 to 5.

7. The valve (i) prevents the flow of the coolant when the clutch pack is in the disengaged state. (ii) allows the flow of the coolant when the clutch pack is in the slipping state. (iii) allows the flow of the coolant when the clutch pack is in the engaged state. The wet clutch according to claim 6.

8. It further includes a plurality of springs individually provided in the hub portion of the plurality of clutch conduits. Each of the plurality of springs biases the pressure plate. The wet clutch according to claim 1.

9. The actuator includes an annular recess formed by the collar and concentric with the shaft, and an annular piston provided in the recess and configured to move axially with respect to the shaft. The wet clutch according to claim 1 or 8.

10. It further includes a flange configured to be provided on the shaft and extending radially. The flange is juxtaposed with the clutch hub. The clutch pack is provided between the flange and the collar. The clutch pack is pushed against the flange when connected by the actuator. The wet clutch according to any one of claims 1 to 9.

11. The wet clutch according to any one of claims 1 to 10, wherein the clutch basket has a cylindrical shape and includes a plurality of openings that allow the coolant to exit radially outward from the wet clutch.

12. A gear assembly provided on a shaft having an internal shaft conduit for a coolant, the shaft penetrating through the whole, a gear wheel configured to be rotatably supported with respect to the shaft, comprising the wet clutch according to any one of claims 1 to 11, the wet clutch being operably connected to the internal shaft conduit and provided on the shaft, the clutch basket of the wet clutch being attached to the gear wheel, a gear assembly.

13. a radial spacer configured to be fixed in the rotational direction with respect to the shaft, and the gear assembly according to claim 12, further comprising a radial rotary bearing having an inner race attached to the radial spacer and an outer race attached to the gear wheel.

14. A shaft having an internal shaft conduit for a coolant, and the gear assembly according to claim 12 or 13, the gear assembly being operably connected to the internal shaft conduit and provided on the shaft, a shaft assembly.

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