SYSTEM FOR MGU FROM ENDLESS DRIVE ARRANGEMENT

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims the benefit of U.S. Provisional application 62/614,879, filed January 8, 2018, U.S. Provisional application 62/646,931 , filed March 23, 2018, U.S. Provisional application 62/662,761 , filed April 25, 2018 and U.S. Provisional application 62/663,253, filed April 26, 2018, the contents of all of which are incorporated herein by reference in their entirety. FIELD

[0002] The specification relates generally to pulleys for motor/generator units (MGUs) in hybrid vehicles.

BACKGROUND OF THE DISCLOSURE

[0003] It is known to provide drive systems that permit an MGU in a vehicle to be driven by the crankshaft of the engine, to drive the engine either to start the engine when the engine is stopped (referred to as Belt-Alternator Start (BAS)), or to give a power boost to the power supplied by the engine to the wheels of the vehicle, or to provide function to one or more accessories such as an air conditioning compressor when the engine is off (referred to sometimes as ISAF (Idle-Stop Accessory Function). Flowever, such systems are sometimes complex, expensive and unreliable. Accordingly, there is a need for new systems that can provide this functionality. SUMMARY OF THE DISCLOSURE

[0004] In one aspect, there is provided an endless drive arrangement for an internal combustion engine, comprising a crankshaft pulley supported by a crankshaft of the engine for rotation therewith, a first MGU pulley supported by an MGU shaft of an MGU, wherein the first MGU pulley is operatively connected to the crankshaft pulley via a first endless drive member, a second MGU pulley supported by the MGU shaft for rotation therewith, wherein the second MGU pulley is operatively connected to at least one accessory that is to be driven thereby, via a second endless drive member, a first wrap spring clutch that is connectable between the second MGU pulley and the first MGU pulley to transfer torque from the second MGU pulley to the first MGU pulley during rotation of the second MGU pulley in a first rotational direction, wherein the first wrap spring clutch has a tang, an actuator that is operatively connected to the tang and which is positionable in a first position in which the actuator and the tang permit torque transfer from the second MGU pulley to the first MGU pulley through the first wrap spring clutch, and a second position in which the actuator and the tang prevent torque transfer from the second MGU pulley to the first MGU pulley through the first wrap spring clutch, a second wrap spring clutch that is connected between the first MGU pulley and the second MGU pulley to transfer torque from the first MGU pulley to the second MGU pulley during rotation of the first MGU pulley in the first rotational direction, wherein, regardless of whether the actuator is in the first or second position, the first MGU pulley is drivable by the first endless drive member such that torque is transferred from the first MGU pulley to the second MGU pulley via the second wrap spring clutch, and from the second MGU pulley to the MGU shaft and to the at least one accessory, wherein, when the actuator is in the first position, the second MGU pulley is drivable by the MGU shaft such that torque is transferred from the second MGU pulley to the first MGU pulley via the first wrap spring clutch, and from the second MGU pulley to the at least one accessory via the second endless drive member, and from the first MGU pulley to the crankshaft pulley via the first endless drive member, wherein, when the actuator is in the second position, the second MGU pulley is drivable by the MGU shaft such that torque is transferred from the second MGU pulley to the at least one accessory via the second endless drive member and wherein the first wrap spring clutch disconnects the second MGU pulley from the first MGU pulley.

BRIEF DESCRIPTIONS OF THE DRAWINGS [0005] For a better understanding of the various embodiments described herein and to show more clearly how they may be carried into effect, reference will now be made, by way of example only, to the accompanying drawings in which:

[0006] Figure 1 is an elevation view of an engine that includes an MGU and a multi- pulley pulley system for the MGU; [0007] Figure 2A is a perspective view of a multi-pulley pulley system for the MGU;

[0008] Figure 2B is another perspective view of a multi-pulley pulley system for the MGU;

[0009] Figure 3 is an exploded perspective view of the multi-pulley pulley system shown in Figures 2A and 2B;

[0010] Figure 3 is another exploded perspective view of the multi-pulley pulley system shown in Figures 2A and 2B;

[0011] Figure 5 is a sectional side view of the multi-pulley pulley system in a first mode, wherein the MGU is driven by the crankshaft;

[0012] Figure 6 is a sectional side view of the multi-pulley pulley system in a second mode, wherein the MGU can drive the engine either to start the engine when the engine is stopped, or to give a power boost to the power supplied by the engine to the wheels of the vehicle (not shown);

[0013] Figure 7 is a sectional side view of the multi-pulley pulley system in a third mode, wherein the MGU can provide function to one or more accessories when the engine is off;

[0014] Figure 8 is a perspective view of the multi-pulley pulley system showing an entirety of an actuator in a first position; [0015] Figure 9 is a sectional perspective view of a portion of the multi-pulley pulley system;

[0016] Figure 10 is a perspective view of the multi-pulley pulley system showing the entirety of an actuator in a second position; [0017] Figure 11 A is a sectional side view of a portion of the actuator when the actuator is in the first position;

[0018] Figure 11 B is a sectional side view of a portion of the actuator when the actuator is in the second position;

[0019] Figure 12 is a perspective view of a variant of the actuator; and [0020] Figure 13 is a sectional side view of a multi-pulley pulley system in accordance with another embodiment of the present disclosure.

DETAILED DESCRIPTION

[0021] For simplicity and clarity of illustration, where considered appropriate, reference numerals may be repeated among the Figures to indicate corresponding or analogous elements. In addition, numerous specific details are set forth in order to provide a thorough understanding of the embodiments described herein. Flowever, it will be understood by those of ordinary skill in the art that the embodiments described herein may be practiced without these specific details. In other instances, well-known methods, procedures and components have not been described in detail so as not to obscure the embodiments described herein. Also, the description is not to be considered as limiting the scope of the embodiments described herein.

[0022] Various terms used throughout the present description may be read and understood as follows, unless the context indicates otherwise:“or” as used throughout is inclusive, as though written“and/or”; singular articles and pronouns as used throughout include their plural forms, and vice versa; similarly, gendered pronouns include their counterpart pronouns so that pronouns should not be understood as limiting anything described herein to use, implementation, performance, etc. by a single gender;“exemplary” should be understood as“illustrative” or“exemplifying” and not necessarily as“preferred” over other embodiments. Further definitions for terms may be set out herein; these may apply to prior and subsequent instances of those terms, as will be understood from a reading of the present description.

[0023] Any module, unit, component, server, computer, terminal, engine or device exemplified herein that executes instructions may include or otherwise have access to computer readable media such as storage media, computer storage media, or data storage devices (removable and/or non-removable) such as, for example, magnetic disks, optical disks, or tape. Computer storage media may include volatile and non-volatile, removable and non-removable media implemented in any method or technology for storage of information, such as computer readable instructions, data structures, program modules, or other data. Examples of computer storage media include RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can be accessed by an application, module, or both. Any such computer storage media may be part of the device or accessible or connectable thereto. Further, unless the context clearly indicates otherwise, any processor or controller set out herein may be implemented as a singular processor or as a plurality of processors. The plurality of processors may be arrayed or distributed, and any processing function referred to herein may be carried out by one or by a plurality of processors, even though a single processor may be exemplified. Any method, application or module herein described may be implemented using computer readable/executable instructions that may be stored or otherwise held by such computer readable media and executed by the one or more processors.

[0024] The present disclosure relates to a pulley system 10 for an MGU (motor-generator unit) shaft 18 of an MGU 15 on a vehicular engine 12. The vehicular engine 12 may be any suitable internal combustion engine, and may have any suitable number of cylinders. A crankshaft pulley 24 supported by a crankshaft 20 of the engine 12 for rotation therewith. Any of the pulleys described in the present disclosure may, as appropriate, have teeth, or may have a smooth belt-engagement surface, or may have one or more V’s on their belt- engagement surface.

[0025] The pulley system 10 provides the engine 12 with the capability to operate in any of three modes, including a first mode in which the crankshaft 20 drives the MGU (and the MGU acts as a generator), and in which the crankshaft 20 also drives the shaft 18 of at least one other accessory 16; a second mode in which the MGU acts as a motor to drive the crankshaft to provide additional power during operation of the vehicle (or to start the engine via the crankshaft) and in which the MGU also drives the at least one accessory 16, and a third mode where the engine is off and the MGU acts as a motor to drive the at least one accessory 16 (e.g. air conditioning compressor 38), but does not transmit torque to the crankshaft 20 to drive the crankshaft.

[0026] The pulley system includes a first pulley 30, a second pulley 32, a first wrap spring clutch 34, and a second wrap spring clutch 36. The first pulley 30 is supported by the MGU shaft 18. In the present example, the first pulley 30 is rotatably mounted to the MGU shaft via a first pulley bearing 37 (e.g. a needle bearing). The first pulley 30 is operatively connected to the crankshaft pulley 24 of the engine 12 via a first endless drive member 14.

[0027] The second MGU pulley 32 is supported by the MGU shaft 18 for rotation therewith. The second MGU pulley 32 is operatively connected to the at least one accessory 16 that is to be driven thereby (e.g. the air conditioning compressor 38), via a second endless drive member 40. While not shown, it will be noted that even if the second MGU pulley 32 includes one or more isolation springs between its belt-engagement surface (shown at 100) and its hub 102 where it connects fixedly to the MGU shaft 18, it can still be referred to as being supported by the MGU shaft 18 for rotation therewith.

[0028] While the first and second MGU pulleys 30 and 32 are said to be supported by the MGU shaft 18, they may be supported by an extension member (shown at 104 in Figure 5) that is fixedly mountable to the MGU shaft 18, (e.g. via an internally threaded portion 106 that threads onto an externally threaded portion 108 of the MGU shaft 18).

[0029] The endless drive members 14 and 40 described herein may be any suitable endless drive members such as belts with teeth, belts with smooth drive surfaces, and belts with one or more V’s in the drive surface, as are known in the art of torque transfer between components in vehicular drive systems.

[0030] The first wrap spring clutch 34 is connectable between the second MGU pulley 32 and the first MGU pulley 30 to transfer torque from the second MGU pulley 32 to the first MGU pulley 30 during rotation of the second MGU pulley 32 in a first rotational direction (clockwise in Figure 1 ). The first wrap spring clutch 34 may transfer torque in any suitable way. In the present example, the first wrap spring clutch 34 has a first end with a foot 110 that extends generally in a helical direction and engages a first drive wall (not shown) in a carrier member 43 (also referred to as a carrier 43 for simplicity). The carrier 43 snugly receives the foot 110 of the wrap spring clutch 34, as is known in the art of decouplers (see, for example, US Patent US8888619B2). The carrier 43 is captured between a first driver 44 and a second driver 46 and is fixedly connected to both the first and second drivers 44 and 46 for torque transfer therewith. The first and second drivers 44 and 46 are fixedly mounted to an inner extension member 112 of the first MGU pulley 30.

[0031] The first wrap spring clutch 34 has a plurality of coils 1 14 and has a radially outer surface 116 which is engageable with an inner surface 118 of the second pulley 32. The first wrap spring clutch 34 receives torque from the second pulley 32 via the engagement of the outer surface 116 with the inner surface 118 and transfers torque into the carrier 43 via the foot 110 and the first drive wall of the carrier 43, which in turn transfers torque into the first pulley 30 due to the connection between the carrier 43 and the first and second drivers 44 and 46 and their connection with the inner extension member 112.

[0032] The second wrap spring clutch 36 is connected between the first MGU pulley 30 and the second MGU pulley 32 to transfer torque from the first MGU pulley 30 to the second MGU pulley 32 during rotation of the first MGU pulley 30 in the first rotational direction. The second wrap spring clutch 32 may transfer torque in any suitable way. In the example shown, the second wrap spring clutch 36 has a foot 80 that is engaged with a second drive wall in the carrier 43. The carrier 43 snugly receives the foot 80 in similar manner to receiving the foot 110 from the first wrap spring clutch 34. The second wrap spring clutch 36 has a plurality of coils 82 and has a radially outer surface 84 which is engageable with the inner surface 118 of the second pulley 32. [0033] The second wrap spring clutch 36 receives torque from the first pulley 32 via the engagement of the second drive wall in the carrier 43 with the foot 80, and transfers torque into the second MGU pulley 32 via engagement between the outer surface 84 with the inner surface 1 18 of the second MGU pulley 32. Thus, rotation of the first MGU pulley 30 in the first rotational direction relative to the second MGU pulley 32 drives the drivers 44 and 46, which in turn drive the carrier 43, which in turn drives the second wrap spring clutch 36, which in turn drives (i.e. transfers torque to) the second MGU pulley 32.

[0034] The first wrap spring clutch 34 has a tang 120 at its second end as best seen in Figure 9. An actuator 122 is operatively connected to the tang 120 and is positionable in a first position (Figure 11A) in which the actuator 122 and the tang 120 permit torque transfer from the second MGU pulley 32 to the first MGU pulley 30 through the first wrap spring clutch 34, and a second position (Figure 1 1 B) in which the actuator 122 and the tang 120 prevent torque transfer from the second MGU pulley 32 to the first MGU pulley 30 through the first wrap spring clutch 34.

[0035] The actuator 122 may have any suitable structure. In the present example, the actuator 122 includes a solenoid 124, a connecting arm 126, a follower 128, which is driven rotationally relative to an actuator base 130 which is fixedly mounted to a structural member in the vehicle such as the support frame that holds the MGU 16. The rotational movement of the follower 128 also drives the follower 128 to move axially (i.e. along the axis of rotation of the pulleys 30 and 32). This axial movement is due to cam pins 132 on the follower 128 that engage suitably angled cam slots 134 in the actuator base 130. In an alternative embodiment shown in Figure 12, the follower 128 may include a set of angled teeth 135a which ride on similarly angled teeth 135b of the actuator base 130.

[0036] The follower 128 engages a control driver 136 that has holder pins 138 thereon. The holder pins 138 pass through apertures 139 in a radial flange portion 140 of the first MGU pulley 30. An armature 142 is on the other side of the flange portion 140 relative to the control driver 136. The armature 142 has a tang slot 144 therein which receives the tang 120. When the holder pins 138 engage armature apertures 146 in the armature 142, the armature prevents movement of the tang rotationally, relative to the first MGU pulley 30. This prevents relative rotational movement between the foot 1 10 of the first wrap spring clutch 34 and the tang 120, thereby preventing the coils 114 of the first wrap spring clutch 34 from expanding into engagement with the inner surface 118 of the second MGU pulley 36 and receiving torque therefrom. When the solenoid 124 is in an extended position, also called a second solenoid position (Figure 10) the follower 128 is rotated such that the follower 128 advances the control driver 136 forward (Figure 11 B) to drive the holder pins 138 into the armature apertures 146 in the armature 142. When the solenoid is in a retracted position, also called a first solenoid position (Figure 8), the follower 128 is urged back to a retracted position by a control driver biasing structure 150 (e.g. a plurality of compression springs 152) such that the holder pins 138 are removed from the armature apertures 146. As a result, the tang 120 of the first wrap spring clutch 34 is free to move rotationally relative to the foot 110 of the first wrap spring clutch 34. Put another way, the second end of the first wrap spring clutch 34 is free to move rotationally relative to the first end of the first wrap spring clutch 34. This relative movement permits the coils 114 of the first wrap spring clutch 34 to expand rotationally when frictionally engaged by the inner surface 118 of the second MGU pulley 32 thereby causing them to lockingly engage the inner surface 118 so as to receive torque from the second MGU pulley 32 and transfer the torque into the first MGU pulley 30 via the foot 110 and the carrier 43.

[0037] When the solenoid 124 is retracted, the actuator 122 may be said to be in a first position. When the solenoid 124 is advanced to the second solenoid position the actuator 122 may be said to be in a second position. When the actuator 122 is in the first position, the actuator 122 and the tang 120 permit torque transfer from the second MGU pulley 32 to the first MGU pulley 30 through the first wrap spring clutch 34. When the actuator 122 is in the second position, the actuator 122 and the tang 120 prevent torque transfer from the second MGU pulley 32 to the first MGU pulley 30 through the first wrap spring clutch 34.

[0038] The actuator 122 in the present embodiment includes a solenoid as the prime mover, however any other suitable type of prime mover may be used, such as a thermal wax actuator, a bimetallic snap disc, a pneumatic ram, a vacuum actuator, or any other suitable type of rotary or linear actuation device.

[0039] When the actuator is moved back to its original position, the follower is brought back to its original position. Biasing elements (e.g. compression springs), drive the control fork axially to withdraw the pins from the armature apertures. This permits the first wrap spring clutch to return to its engagement position.

[0040] Figure 5 shows the torque transfer that takes place when the first MGU pulley 30 is rotated in the first rotational direction relative to the second MGU pulley. As will be understood, the torque is transferred into the first MGU pulley 30 from the crankshaft 20 via the first endless drive member 14. The torque is transferred from the inner extension member 112 to the drivers 44 and 46, to the carrier 43, to the second wrap spring clutch 36 and into the second MGU pulley 32 and then into the MGU shaft 18 and into the at least one accessory 16 via the second endless drive member 40. This occurs regardless of the position of the actuator 122. This permits the MGU to act as an alternator and to charge the battery of the vehicle (not shown) by the crankshaft 20, and to permit driving of the at least one accessory from the crankshaft 20.

[0041] Figure 6 shows the torque transfer that occurs when the actuator 122 is in the first position and when the MGU pulley 32 is rotated in the first direction relative to the first MGU pulley 30. Torque is transferred from the MGU shaft into the second MGU pulley 32 and from there into the at least one accessory 16, and also into the first MGU pulley 30 via the first wrap spring clutch 34, the carrier 43 and the drivers 44 and 46. From the first MGU pulley 30 torque is transferred to the crankshaft 20 via the first endless drive member 14. This permits starting the engine or boosting of the engine’s power output.

[0042] Figure 7 shows the torque transfer that occurs when the actuator 122 is in the second position and when the MGU pulley 32 is rotated in the first direction relative to the first MGU pulley 30. As can be seen torque is transferred from the MGU shaft into the second MGU pulley 32 and from there into the at least one accessory 16, but not into the first MGU pulley 30. This provides ISAF functionality.

[0043] While torque transfer took place through the wrap spring clutches 34 and 36 via a foot and via an outer surface of the coils, it will be noted that torque transfer could instead be carried out in any other suitable way known for wrap spring clutches. For example, torque transfer could be provided by engagement of a radially inner surface of the coils of one of the wrap spring clutches with suitable outer faces of the pulleys 30 and 32 or elements connected to the pulleys 30 and 32 (sometimes referred to as a shaft-to-shaft torque transfer). Similarly, torque transfer could be provided by engagement of a radially outer surface of the coils of one of the wrap spring clutches with suitable inner faces of the pulleys 30 and 32 or elements connected to the pulleys 30 and 32 (sometimes referred to as a drum-to-drum torque transfer). An example of an arrangement that includes one of each of these types of wrap spring clutches is shown in Figure 13.

[0044] Persons skilled in the art will appreciate that there are yet more alternative implementations and modifications possible, and that the above examples are only illustrations of one or more implementations. The scope, therefore, is only to be limited by the claims appended hereto and any amendments made thereto.