FIELD

[0001] The described examples relate generally to a belt tensioner, and more particularly to belt-driven starter-generator (BSG) systems and techniques that facilitate connecting a BSG tensioner device to a Motor Generator Unit.

BACKGROUND

[0002] Belt tensioners are used to apply a load to a belt. The belt load prevents the belt from slipping on one or more entrained pulleys during operation. Typically, the belt is used in an engine application for driving various accessories associated with the engine. For example, an air conditioning compressor and an alternator are two possible accessories that can be driven by a belt drive system.

[0003] A belt tensioner may include a pulley mounted to an arm. A spring is connected between the arm and a base. The spring may also engage a damping mechanism. The damping mechanism comprises a frictional surface engaged with the arm or the base. The damping mechanism dissipates vibration energy from the belt system and reduces oscillatory movement of the arm that is caused by rotational vibration of the engine crankshaft during operation of the belt drive.

[0004] Belt tensioners have been used for a very long time in the belt-pulley power transmission industry. For example, in the automotive industry, tensioners have been used to adjust and optimize the belt tension for target performance of serpentine belt drives. Conventional mechanical tensioners typically control belt tension at a belt span. The belt span may typically be a slack-side of the belt, for example, due to the accessory loads being in a common direction at the slack-side, as driven by the engines. For BSG systems, special tensioners are designed to control belt tension according to MGU operations. For example, in a generating mode, the tensioner may operate to control tension of a slack-side span, which is located before MGU pulley in belt moving direction. As another example, in a motoring mode, when the pulley becomes a driver, the tensioner may operate to control tension of another slackside span.

[0005] The housings or bases of BSG tensioners are typically bolted or otherwise fixed relative to a Motor Generator Unit housing, engine block or engine associated structure. Such BSG tensioner mounting increases the footprint and weight of the tensioner and the mounting counterpart, and reduces the adaptability of the tensioner to certain high-performance applications. Further drawbacks of conventional systems include the belt alignment with the MGU pulley. For example, if the tensioner arm pulley before the MGU pulley in the belt moving direction does not maintain the required bearing seat angle or height, the belt may be damaged in operation or fall off the pulley. Typical tensioner device mountings may result in belt misalignment from manufacturing tolerance of tensioner base and mounting counterpart, and wearing of supporting elements such as plastic bearing bushings between tensioner’s base and arm. As such, the need continues for systems and techniques to optimize the performance of tensioner devices, including those that reduce weight and complexity without sacrificing performance including alignment.

SUMMARY

[0006] Examples of the present invention are directed to tensioner devices, coupling features that facilitate direct coupling of tensioner devices to Motor Generator Units, and assemblies and methods of manufacture thereof.

[0007] In a first example, a tensioner device for installation on a Motor Generator Unit (MGU) is disclosed. The tensioner device includes a first pulley mountable on a rotatable shaft of the MGU for turning with a rotation of the rotatable shaft. The first pulley is adapted to engage and drive, or be driven by, a belt. The tensioner device further includes a coupling feature mountable on one of a support structure of the MGU or the rotatable shaft. The support structure is arranged about the rotatable shaft. The tensioner device further includes a first rotary arm connected to the coupling feature. The coupling feature is adapted to allow for movement of the first rotary arm relative to the support structure. The tensioner device further includes a second rotary arm arranged for movement relative to the first rotary arm. The tensioner device further includes a second pulley journalled to the second rotary arm and adapted to engage the belt using a biasing element. The tensioner device further includes a third pulley journalled within the tensioner device for engagement of the belt. The second and third pulleys being disposed about the first pulley for establishing a belt path along the first, second, and third pulleys.

[0008] In a second example, an assembly is disclosed. The assembly includes a Motor Generator Unit (MGU) with a rotatable shaft. The MGU includes a support structure extending along the rotatable shaft. The assembly further includes a tensioner device mounted directly on the support structure and configured to impart a tension in a belt. The tensioner device includes a first pulley mountable on the rotatable shaft for turning with a rotation of the rotatable shaft. The tensioner device further includes a coupling feature associated with the first pulley and allowing for movement of a tensioning arm of the tensioning device relative to the rotatable shaft.

[0009] In addition to the exemplary aspects and examples described above, further aspects and examples will become apparent by reference to the drawings and by study of the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The disclosure will be readily understood by the following detailed description in conjunction with the accompanying drawings, wherein like reference numerals designate like structural elements, and in which:

[0011] FIG. 1 depicts an example assembly including a Motor Generator Unit and tensioner device;

[0012] FIG. 2 depicts an exploded view of the assembly of FIG. 1;

[0013] FIG. 3 depicts an exploded view of the tensioner device of FIG. 1;

[0014] FIG. 4 depicts a front view of the assembly of FIG. 1;

[0015] FIG. 5 A depicts a cross-sectional view of the assembly of FIG. 1, taken along line 5-5 of FIG. 4;

[0016] FIG. 5B depicts a detail view of the tensioner device of FIG. 5 A having a retaining structure; [0017] FIG. 6 depicts a front view of another example of an assembly including a Motor Generator Unit and a tensioner device;

[0018] FIG. 7 depicts a cross-sectional view of the assembly of FIG. 6, taken along line 7-7 of FIG. 6;

[0019] FIG. 8 depicts a front view of another example of an assembly including a Motor Generator Unit and a tensioner device;

[0020] FIG. 9 depicts a cross-sectional view of the assembly of FIG. 8, taken along line 9-9 of FIG. 9;

[0021] FIG. 10 depicts a detail view of an example of the tensioner device of FIG. 9 in which the biasing element is arranged about the rotatable shaft of the MGU;

[0022] FIG. 11 depicts an example coupling feature and rotary arm in an engaged configuration;

[0023] FIG. 12 depicts an exploded view of the coupling feature and rotary arm of FIG. 11;

[0024] FIG. 13 depicts a cross-sectional view of the coupling feature and rotary arm of FIG. 11, taken along line 13-13 of FIG. 11; and

[0025] FIG. 14 depicts a schematic representation of the coupling feature and rotary arm of FIG. 11 in an installed configuration with another rotary arm and a coupling feature of the MGU.

DETAILED DESCRIPTION

[0026] The description that follows includes sample systems, methods, and apparatuses that embody various elements of the present disclosure. However, it should be understood that the described disclosure may be practiced in a variety of forms in addition to those described herein.

[0027] Before referring to the Figures, a brief explanation is provided. The present disclosure describes tensioner devices, and assemblies and methods of manufacture thereof. A sample tensioner device of the present disclosure may include a pulley that is journalled to an arm. The pulley may be adapted to engage a belt, such as a serpentine belt of an automotive or other engine system. The pulley may apply a load to the belt in order to tension the belt and optimize belt performance. For example, the tensioner devices of the present disclosure may include a biasing element that is adapted to bias the arm (and journalled pulley) toward a run or span of the belt, thereby tensioning the belt to a desired characteristic. Conventional mechanical tensioners often arrange the arm, biasing element, and other components within, or are otherwise associated with, a housing. Such tensioner device housings of the conventional system are then fixed directly to a Motor Generator Unit (MGU) or other engine component for installation, with the housing or overall footprint often decreasing the adaptability of the tensioner device.

[0028] The tensioner device of the present disclosure may mitigate such hindrances by implementing a coupling feature and arrangement that allows for attachment of the tensioner device to the MGU without a housing. The coupling feature may allow the tensioner device to be directly coupled, for example, to support structure of the MGU without bolting or otherwise fixing a housing of the tensioner device to the MGU. As described herein, the support structure may be a nose or other structural feature of the MGU housing that extends along a rotatable shaft of the MGU and the tensioner device may be coupled directly to the nose. By removing the housing, the tensioner device of the present disclosure may be lighter and more compact than existing designs without sacrificing performance of the system. Assembly of the tensioner device may also be improved, where the tensioner device is directly coupled to the support structure, thereby reducing or eliminating additional assembly steps associated with bolting or other attachment techniques required to install conventional tensioner devices.

[0029] To facilitate the foregoing, the tensioner device may include a first or “drive” pulley that may be mountable on a rotatable shaft for turning with a rotation of the rotatable shaft. The first pulley may be adapted to engage and drive, or be driven by, a belt. The tensioner device may further include a first rotary arm and a second rotary arm that are moveable relative to one another. A second or “idler” pulley may be journalled to the second rotary arm to engage and tension the belt. Tension may be established using a biasing element operatively connected to the first and second rotary arms. A third or “idler” pulley may be journalled to the first rotary arm allowing the first, second, and third pulleys to establish a belt path relative to the MGU.

[0030] A coupling feature of the tensioner device facilitates direct coupling of the tensioner device to the MGU without relying on excess housing components. Broadly, the coupling feature may be used to connect the first rotary arm to the support structure of the MGU housing and establish movement of the first rotary arm relative to the support structure and the first pulley. In this regard, the first pulley may turn with the rotation of the rotatable shaft, and the first rotary arm may float relative to otherwise move independent of the movement of the rotatable shaft and first pulley. Other components of the tensioner device may be connected, directly or indirectly, to the first rotary arm, for example, including the second rotary arm, the biasing element, the second pulley, the third pulley, and so on. Accordingly, the coupling features of the present disclosure can allow these and other features to be supported in the tensioner device via the support structure or nose of the MGU, rather than be included in a housing structure of the tensioner device that is independently fixed to the MGU housing or to some other fixed frame on a vehicle.

[0031] The coupling feature, in one example, may include a bushing feature. The bushing feature may be defined by a substantially cylindrical bushing having a first surface and a second opposing surface. The first and second surfaces may be inner and outer surfaces of the cylindrical structure and may cooperate to establish movement of the first rotary arm relative to the support structure and the first pulley. In one illustration, the first surface is engaged with the support structure, and the second surface is engaged with the first rotary arm allowing the first rotary arm to move relative to the support structure. Sample bushing features may include or be associated with a damping feature. This may include examples where the bushing has textured surfaces in order to induce a friction torque between the first rotary arm and the support structure. One bushing feature may be used. In other cases, two bushing features or more may be used, depending on a given application. For example, two bushing features may be used to establish relative movement of a pair of rotary arms, each rotatable about a MGU axis defined by the rotatable shaft of the MGU. Additionally or alternatively, the coupling feature may include a bearing assembly and/or other component that operates to establish movement of the first rotary arm with respect to the support structure.

[0032] It will be appreciated that the coupling feature and techniques herein for mounting a tensioner device to a MGU may be implemented for a variety of different tensioner device structures. In addition to the examples described above, the tensioner device may include a third rotary arm and the third “idler” pulley may be journalled to the third rotary arm. The third pulley may be adapted to apply a load on the belt, in cooperation with the second rotary arm and second pulley. For example, the second and third rotary arms may be attached to opposing ends of the first rotary arm, and a biasing element may extend between the second and third rotary arms. The second and third pulley may then apply complementary forces to the belt, in part due to the cooperative engagement of the second and third rotary arms, as established by the biasing element. In another example implementation, the first and second rotary arms may be configured to rotate about an axis of the MGU defined by the rotatable shaft. In this manner, the biasing element may also be disposed about the MGU axis, and a bushing feature may be provided between the first and second rotary arms to establish relative movement between the arms, with the first rotary arm being moveable relative to the first pulley via the coupling feature, as described above. Other arrangements of the tensioner device are contemplated and described herein.

[0033] Reference will now be made to the accompanying drawings, which assist in illustrating various features of the present disclosure. The following description is presented for purposes of illustration and description. Furthermore, the description is not intended to limit the inventive aspects to the forms disclosed herein. Consequently, variations and modifications commensurate with the following teachings, and skill and knowledge of the relevant art, are within the scope of the present inventive aspects.

[0034] FIG. 1 depicts an example assembly 100. The assembly 100 includes a Motor Generator Unit (MGU) 104 and a tensioner device 120, such as the tensioner device discussed above and described in greater detail below. The tensioner device 120 is shown in FIG. 1 mounted to the MGU 104 without having a housing structure that is directly fixed to the MGU 104. For example, the MGU 104 includes a rotatable shaft 108 (shown in phantom in FIG. 1) and a support structure 110 (FIG. 2) that is arranged about, and generally extends along, the rotatable shaft 108. It will be appreciated that while the rotatable shaft 108 is shown in FIG. 1 as a rotatable shaft of the MGU 104, in other cases, the rotatable shaft 108 can be a rotatable shaft associated with any of a variety of other engine, or more generally rotatable, components. In this regard, the MGU 104 is shown as an example, and the tensioner device 120 may therefore be used to couple with substantially many other rotatable components without departing from the scope of the present disclosure. [0035] The tensioner device 120 is attached to the MGU 104 using the rotatable shaft 108 and the support structure 110. As described in greater detail below, one or more coupling features of the tensioner device 120 (e.g., a bushing feature, a bearing assembly, and so on) may be situated about the rotatable shaft 108 and/or the support structure 110 and allow one or more features of the tensioner device 120 to float or otherwise move relative to the rotatable shaft 108 and support structure 110.

[0036] The assembly 100 is also shown as including a belt 102. The tensioner device 120 is shown in FIG. 1 in an installed configuration in which the tensioner device 120 is mounted to the MGU 104. In the installed configuration, the tensioner device 120 is configured to engage and tension the belt 102. To facilitate the foregoing, the tensioner device 120 includes a first pulley 124 with a first engagement surface 125, a second pulley 128 with a second engagement surface 129, and a third pulley 132 with the third engagement surface 133. The first pulley 124, the second pulley 128, and the third pulley 132 cooperate to establish a belt path 103 of the belt 102 through the assembly 100. The first pulley 124 may define a “drive” pulley adapted to engage and drive, or be driven by, the belt 102. The second pulley 128 and the third pulley 132 may be “idler” pulleys that help define the belt path 103 and/or be used to actively tension the belt 102.

[0037] In the example of FIG. 1, the second pulley 128 is used to actively tension the belt 102 using a biasing element 136 (shown in phantom in FIG. 1). To facilitate the foregoing, the tensioner device 120 includes a first rotary arm 140 and a second rotary arm 144. The first and second rotary arms 144, 140 may include but are not limited to pivot arms. The first and second rotary arms 144, 140 may be elongated structural members; however, this is not required. In other cases, different rotary and/or pivot structures may be used, including plates, linkages, gears and so on. The first rotary arm 140 is shown positioned about an MGU axis 109 that extends a longitudinal axis of the rotatable shaft 108. The second rotary arm 144 may be moveably coupled to the first rotary arm 140 about a tensioner arm axis 135. As shown in FIG. 1, the tensioner arm axis 135 may be offset from the MGU pulley axis 109. In other examples, the tensioner arm axis 135 may be generally co-linear with the MGU pulley axis 109. The biasing element 136 may be operatively coupled to the first rotary arm 140 and the second rotary arm 144, and be arranged to bias the second rotary arm 144 toward the belt 102. The second pulley 128 may be journalled to the second rotary arm 144, and thus the bias of the second rotary arm 144 may cause the second pulley 128 to press into and tension the belt. The third pulley 132 may be journalled to the first rotary arm 140 opposite the second pulley 128, and the second pulley 128 and third pulley 132 are thus biased toward each other by biasing element 136.

[0038] The first rotary arm 140 may be supported in the assembly 100 by the support structure 110 and allowed to float or otherwise move relative thereto and independent of the rotation of the rotatable shaft 108. In this regard, the first rotary arm 140 may structurally support the various components of the tensioner device 120 (e.g., the pulleys 124, 128, 132, the biasing element 136, the second rotary arm 144, and so on), and without needing to turn with a rotation of the rotatable shaft 108. To facilitate the foregoing, the tensioner device 120 may include a coupling feature that allows the first rotary arm 140 to be connected (directly or indirectly) to the rotatable shaft 108 and/or the first pulley 124 while permitting free movement of the first rotary arm 140 with respect to rotatable shaft 108 and/or the first pulley 124.

[0039] With reference to FIG. 2, an exploded view of the assembly 100 is shown including one or more coupling features, such as those described above. In the exploded view of FIG. 2, a coupling feature 148 is shown. In the example of FIG. 2, the coupling feature 148 is shown a bushing feature, such as a cylindrical bushing. In this regard, the bushing feature or coupling feature 148 is shown as including a first surface 150a, and a second surface 150b. The first and second surfaces 150a, 150b are shown as opposing inner and outer surfaces of the cylindrical bushing and may be used to engage and facilitate movement of two or more components of the assembly 100. The coupling feature 148 may be of a material chosen for frictional damping. One or both of the surfaces 150a, 150b may be a textured surface or otherwise be tuned to facilitate damping. Additionally or alternatively, a dampening layer, plate or other damping feature may be applied to one or both of the surfaces 150a, 150b. In other examples, the coupling feature 148 may be adapted as one or more bearing assemblies or other structures that may facilitate movement of the first rotary arm 140 relative to the support structure 110. The coupling feature 148 may be restrained from axial movement along the support structure, which may be facilitated by a pin, restraining ring, or other feature.

[0040] The coupling feature 148 may be connected to the support structure 110 and the first rotary arm 140. In the example of FIG. 2, the coupling feature 148 may be substantially arranged within a through portion 141 of the first rotary arm 140 with the first surface 150a connected to the support structure 110 and the second surface 150b connected to the first rotary arm 140. Movement of the first rotary arm 140 may therefore be defined by the coupling feature 148, and the first rotary arm is thus moveable independent of the rotation of the rotatable shaft 108, while being structurally supported in the assembly 100 by the MGU 104. In some cases, one or both of the first and second surfaces 150a, 150b may be a textured surface or otherwise adapted to generate a frictional resistance, or friction torque, between the first rotary arm 140 and the support structure 110, a described in greater detail below.

[0041] As shown in FIG. 2, the MGU 104 includes a housing 105. The housing 105 may define an exterior shell or other protective casing of the MGU 104. For example, the housing 105 may enclose or substantially enclose various components of the MGU 104, such as motor windings, gears, bearings, and/or various other components. The housing 105 shown in FIG. 2 generally includes a main portion 105a and a nose 105b. The main portion 105a may define a portion of the housing 105 that encloses or substantially encloses the foregoing components of the MGU 104, while the nose 105b may define a protruding-type feature to facilitate mounting of the tensioner device 120. In this regard, the support structure 110 may be defined by the nose 105b of the housing 105. The nose 105b may therefore be a structural feature of the housing 105 that is used to support the tensioner device 120 within the assembly 100. As shown in FIG. 2, the nose 105b may extend from the main portion 105a and may be at least partially surrounding or encircling a proximal end of the rotatable shaft 108. An annular gap 107 may therefore be defined between the support structure 110 and the rotatable shaft 108, within which a portion of the first pulley 124 or other structure of the tensioner device 120 may be inserted to facilitate mounting, as described herein. In some cases, the nose 105b may extend integrally from the main portion 105a such that the nose 105b and main portion 105a are portions of an integrally formed or otherwise one-piece structure.

[0042] Turning to FIG. 3, an exploded view of the tensioner device 120 is shown. As shown in the exploded view, the first rotary arm 140 includes a first rotary arm end 142a and a second rotary arm end 142b. The second rotary arm 144 may be moveable coupled to the first rotary arm 140 at the first rotary arm end 142a. The first rotary arm end 142a may include a mounting feature 180a with a hole 181a defined therethrough. The second rotary arm 144 may define a hole 145a therethrough that may be aligned with the hole 181a along the tensioner arm axis 135. A pin 182 and sleeve 183 may be provided and inserted through the holes 145a, 181a in order to connect the second rotary arm 144 to the first rotary arm 140 at the first rotary arm end 142a. The pin 182 and the sleeve 183 may be used to connect the first and second rotary arms 140, 144 to one another in a manner that allows relative movement between the first and second rotary arms 140, 144.

[0043] The first and second rotary arms 140, 144 may also be biased relative to one another, via operation of the biasing element 136. As one example, the biasing element 136 may have a first portion 137a that is connected to the first rotary arm 140 and a second portion 137b that is connected to the second rotary arm 144. The first and second portions 137a, 137b may be moved or otherwise angularly displaced relative to one another in order to store energy for subsequent release to bias the second rotary arm 144 to tension the belt 102. In the example of FIG. 3, the biasing element 136 is shown as a torsion spring, with the first and second portions 137a, 137b being respective ends of the torsion spring. In other cases, other biasing elements may be used, including leaf springs.

[0044] The second rotary arm 144 is also shown in FIG. 3 as including a hole 145b. The hole 145b may be used to facilitate attachment of the second pulley 128 to the second rotary arm 145. For example, the second pulley 128 may be connected to the second rotary arm 144 at the hole 145b using a pulley bearing 130, as shown in FIG. 3. The pulley bearing 130 may be used to rotatably couple the second pulley 128 to the second rotary arm 144, thereby allowing the second pulley 128 to rotate as the second engagement surface 129 engages the belt 102. To facilitate the foregoing, a plug 184, a cap 186, and a pin 188 is provided. The plug 184 may seat an inner race of the pulley bearing 130 and be arranged along a first end of the second pulley 128. The cap 186 may be arranged along a second, opposing end of the second pulley 128 and close the pulley bearing 130 within the second pulley 128 with the plug 184. The pin 188 may extend through the hole 145b, and through a hole 187 of the cap 186 and a hole 185 of the plug 184, securing the second pulley 128 to the second rotary arm 144 while allowing the second pulley 128 to rotate, using the pulley bearing 130. [0045] Also shown in FIG. 3, the third pulley 132 is attached to the first rotary arm 140 at the second rotary arm end 142b. The second rotary arm end 142b may include a mounting feature 180b with a hole 181b defined therethrough. The mounting feature 180b may seat an inner race of a pulley bearing 134. The pulley bearing 134 may be installed within the third pulley 132. A cap 189 may be arranged adjacent the third pulley 132, opposite the mounting feature 180b. A pin 190 may be provided that is extendable through a hole 191 in the cap 189 and into the hole 180b of the first rotary arm 140. Accordingly, the third pulley 132 may be secured to the first rotary arm 140 while be allowed to rotate relative thereto with the operation of the pulley bearing 134.

[0046] In FIG. 4, a front view of the assembly 100 is shown. FIG. 4 shows the tensioner device 120 mounted to the MGU 104 about the rotatable shaft 108. In the front view of FIG. 4, the assembly 100 is shown as having a damping assembly 155 (shown in phantom). The damping assembly 155 may be an optional external damping assembly that is mounted directly to the MGU 104. The damping assembly 155 may include a damping mount 156 that is configured to attach the damping assembly 155 to the MGU 104. The damping assembly 155 may pivot or otherwise move relative to the MGU 104 about the damping mount 156. To facilitate damping, the damping assembly 155 is shown as including a damping feature 158 and a guide portion 159. The guide portion 159 helps maintain a position of the damping assembly 155 relative to first rotary arm 140 and/or first pulley 124. The damping feature 158 may be adapted to contact one or both of the first rotary arm 140 and/or the first pulley 124 to generate a friction torque therewith. The damping feature 158 can have a geometry and material adapted to tune the friction torque to a desired value.

[0047] With reference to FIG. 5 A, a cross-sectional view of the assembly 100 is shown, taken along line 5-5 of FIG. 4. In the cross-sectional view of FIG. 5A, the tensioner device 120 is shown mounted to the MGU 104 using the first pulley 124, and the coupling feature 148. The tensioner device 120 is mounted to the MGU in a manner that allows the first pulley 124 to turn with a rotation of the rotatable shaft 108, while allowing the first rotary arm 140 to float or otherwise move independent of the rotation of the rotatable shaft 108. [0048] In the example of FIG. 5A, the first pulley 124 is fixed to the rotatable shaft 108. The rotatable shaft 108 may define shaft threads 111b and the first pulley 124 may define pulley threads I l la. The shaft threads 111b may be arranged along the rotatable shaft 108 and along the MGU axis 109. The pulley threads I l la may be defined by a hub 113 of the first pulley 124 that is adapted to receive the rotatable shaft 108. The shaft threads 111b and the pulley threads I l la may be threadably coupled to one another in order to fix the first pulley 124 to the rotatable shaft 108. The shaft threads 111b and the pulley threads I l la may be arranged to mitigate loosening the first pulley 124 from the rotatable shaft 108 during rotation. A retaining ring, nut, splines, and/or other feature may be implemented in order to secure the first pulley 124 and the rotatable shaft 108 to one another.

[0049] As one example, FIG. 5 A includes a nut 114. The nut 114 may be used to axially restrain the first pulley 124 along the rotatable shaft 108. This may prevent exit of the first pulley 124 from the assembly 100 during operation. Alternatively, a series of splines 116 may also be used to facilitate connection of the first pulley 124 and the rotatable shaft 108, as shown in FIG. 5A in phantom line.

[0050] As shown in FIG. 5 A, the coupling feature 148 operates to connect the first rotary arm 140 and the support structure 110 to one another. The first pulley 124 is therefore allowed to turn with a rotation of the rotatable shaft 108, while the first rotary arm 140 is free to float or move independent of the rotation of the rotatable shaft 108 and the first pulley 124 via operation of the coupling feature 148.

[0051] In the example of FIG. 5 A, the coupling feature 148 is shown with the first surface 150a connected to the support structure 110 and the second surface 150b connected to the first rotary arm 140. For example, the support structure 110 may define a nose of the MGU housing 105 (as described above with respect to FIG. 1) that extends elongated along an elongated portion 112 of the rotatable shaft 108 and the first surface 150a may be secured to the nose, including being seated directly thereon. In this regard, the first surface 150a may turn relative to the MGU housing 105, including being adapted to rotate about the support structure 110. The coupling feature 148 may be slid or otherwise fitted over the nose. In some case, retaining rings 160a, 160b, as shown in the example of FIG. 5B, may be used to impede axial movement of the coupling feature 148 along the support structure 110.

[0052] As further shown in FIG. 5 A, the first rotary arm 140 may include a mounting portion 143. The second surface 150b of the coupling features 148 may be secured to the mounting portion 143, including being seated directly thereon. For example, the mounting portion 143 may generally define the through portion 141 shown in FIG. 2. The mounting portion 143 may be fitted about the rotatable shaft 108 and the second surface 150b or other component of the coupling feature 148 may be seated thereon. As described herein, the first and second surfaces 150a, 150b may be opposing surfaces of a cylindrical bushing, and thus adaptable to establish movement between components engaged with each opposing surfaces, respectively.

Accordingly, the first rotary arm 140 may move relative to or float with respect to the rotation of the support structure 110 while being structurally supported by the support structure 110, in light of the operation of the coupling feature 148.

[0053] As described herein, tensioner devices of various types and configurations may be adapted for mounting with an MGU, according to the techniques described herein. For example, coupling features may be used to mount a tensioner device about a support structure of an MGU housing for tensioner devices having different quantities and/or arrangements of rotary arms, and other arrangements, as suited for a particular application. In this regard, FIGS. 6-9 show two alternative tensioner device structures that are directly mountable to an MGU. It will be appreciated that tensioner devices of FIGS. 6-9 are presented for purposes of illustration. Other arrangements of the tensioner device, directly coupled with the MGU using the coupling features of the present disclosure, are contemplated herein.

[0054] With reference to FIGS. 6 and 7, a front view of an assembly 600 is shown. The assembly 600 includes an MGU 604 and a tensioner device 620. The tensioner device 620 may be substantially analogous to the tensioner device 120 and may be adapted to engage and tension a belt 602 associated with the MGU 604. For example, the MGU 604 may include a rotatable shaft 608 (shown in phantom in FIG. 6) and the tensioner device 620 may include a first pulley 624 that is adapted to drive, or be driven by, a belt. The tensioner device 620 also includes a first rotary arm 640. The first rotary arm 640, as described herein with reference to FIG. 7, is connected to the first pulley 624 and/or the rotatable shaft 608 via one or more coupling features. The first rotary arm 640 is therefore adapted to float or move relative to the first pulley 624 and/or the rotatable shaft 608, while supporting various other components of the tensioner device 620 within the system, including additional rotary arms, pulleys, biasing elements, and so on.

[0055] The tensioner device 620 shown in FIG. 6 may be used to apply tension to multiple runs of the belt. For example, the tensioner device 620 may include multiple pulleys that are each adapted to engage and tension the belt using one or more biasing elements of the tensioner device 620. To facilitate the foregoing, in the example of FIG. 6, the tensioner device 620 includes a second rotary arm 644, a second pulley 628, a third rotary arm 660, a third pulley arm 632, and a biasing element 636. The first rotary arm 640 may be situated about the rotatable shaft 608 and have a first end 642a and a second end 642b. The first and second ends 642a, 642b may define opposing ends of the first rotary arm 640, with the first end 642a defining a first tensioner arm axis 635a and the second end 642b defining a second tensioner arm axis 635b (e.g., as shown in FIG. 7). The second rotary arm 644 may be moveably coupled to the first rotary arm 640 at the first end 642a and allowed to pivot about the first tensioner arm axis 635a. The second rotary arm 644 may include a second rotary arm tensioner section 646a and a second rotary arm biasing element section 646b. The second rotary arm tensioner section 646a and the second rotary arm biasing element section 646b are show in FIG. 6 as extending opposingly away from the first tensioner arm axis 635a. Further, the third rotary arm 660 may be moveably coupled to the first rotary arm 640 at the second end 642b and allowed to pivot about the second tensioner arm axis 635b. The third rotary arm 660 may include a third rotary arm tensioner section 662a and a third rotary arm biasing element section 662b. The third rotary arm tensioner section 662a and the third rotary arm biasing element section 662b are show in FIG. 6 as extending opposingly away from the second tensioner arm axis 635b.

[0056] The biasing element 636 may generally extend between the second rotary arm 644 and the third rotary arm 660. In the example of FIG. 6, the biasing element 636 includes a first portion 637a that is connected to the third rotary arm 660 at the third rotary arm biasing element section 662b. The biasing element 636 also includes a second portion 637b that is connected to the second rotary arm 644 at the second rotary arm biasing element section 646b. In some cases, as shown in FIG. 6, the biasing element 636 is a helical-type spring with the first portion 637a and the second portion 637b being opposing ends of a coil. In other cases, other biasing elements may be used, including leaf springs and the like.

[0057] The biasing element 636 may be used to encourage movement of the second rotary arm 644 and the third rotary arm 660. For example, the biasing element 636 may direct the second rotary arm biasing element section 646b and the third rotary arm biasing element section 662b away and/or toward one another, based in part on the spring characteristics and geometry of the biasing element 636. Movement of the second rotary arm biasing element section 646b and the third rotary arm biasing element section 662b may in turn cause the second rotary arm 644 and the third rotary arm 660 to pivot about the first and second tensioner arm axis 635a, 635b, respectively. This movement may be used to apply a force to belt engaged with the tensioner device 620.

[0058] For example, the second pulley 628 may be journalled to the second rotary arm 644 at the second rotary arm tensioner section 646a and positioned for engagement with the belt. Further, the third pulley 632 may be journalled to the third rotary arm 660 at the third rotary arm tensioner element section 662a and positioned for engagement with the belt. As the second and third rotary arms 644, 660 pivot about the respective first and second tensioner arm axis 635a, 635b (via the operation of the biasing element 636), the pulleys 628, 632 may move toward and impart a load to the belt for tensioning. It will be appreciated that the characteristics of the biasing element 636, and geometry and arrangement of the pulleys 624, 628, 632 and rotary arms 640, 644, 660 may be tuned in order to tension the belt to a desired value.

[0059] With reference to FIG. 7, a cross-sectional view of the assembly of FIG. 6, taken along line 7-7 of FIG. 6 is shown. As shown in cross-sectional view of FIG. 7, the MGU 604 includes the rotatable shaft 608 with an elongated portion 612, and threads 611b. A support structure 610 of a housing 605 of the MGU 604 may extend along the rotatable shaft 608. As further shown in the cross-sectional view of FIG. 7, the tensioner device 620 includes a hub 613, threads 611a and a first engagement surface 625 of the first pulley 624, a nut 614, splines 616, a mounting portion 643 of the first rotary arm 640, a mounting feature 680a and a hole 681a of the first end 642a, a pin 682, a sleeve 683, a mounting feature 680b and a hole 681b of the second end 642b, a pin 664, a sleeve 665, and a coupling feature 648 with a first surface 650a and a second surface 650b.

[0060] The first rotary arm 640 is connected to the support structure 610 using the coupling feature 648. The coupling feature 648 may operate substantially analogous to the coupling feature 148, including being used to facilitate damping; redundant explanation of which is omitted here for clarity. The first rotary arm 640 is therefore arranged about the support structure 610 for movement about the MGU axis 609. The first rotary arm 640 is also operable to support the second rotary arm 644 in the tensioner device 620. For example, the pin 682 and the sleeve 683 may be inserted through the second rotary arm 644 with the pin 682 at least partially inserted into the hole 681a of the first rotary arm 640 at the first end 642a. The second rotary arm 644 may thus be seated about the mounting feature 680a and the pin 682 may extend along the first tensioner arm axis 635a to establish a pivoting relationship between the second rotary arm 644 and the first rotary arm 640.

[0061] Correspondingly, the first rotary arm 640 is also operable to support the third rotary arm 660 in the tensioner device 620. For example, the pin 664 and the sleeve 665 may be inserted through the third rotary arm 660 with the pin 664 at least partially inserted into the hole 681b of the first rotary arm 640 at the second end 642b. The third rotary arm 660 may thus be seated about the mounting feature 681a and the pin 664 may extend along the second tensioner arm axis 635b to establish a pivoting relationship between the third rotary arm 660 and the first rotary arm 640.

[0062] A stated above, the tensioner devices of various types and configurations may be adapted for mounting with an MGU, according to the techniques described herein. For example, coupling features may be used to mount a tensioner device about a rotational shaft of the MGU for tensioner devices having different quantities and/or arrangements of rotary arms, and other arrangements, as suited for a particular application. With reference to FIGS. 8-10, another example arrangement of a tensioner device, directly coupled with the MGU using the coupling features of the present disclosure, is shown.

[0063] Turning to FIG. 8, a front view of an assembly 800 is shown. The assembly 800 includes an MGU 804 and a tensioner device 820. The tensioner device 820 may be substantially analogous to the tensioner device 120 and may be adapted to engage and tension a belt 802 associated with the MGU 804. For example, the MGU 804 may include a rotatable shaft 808 (shown in phantom in FIG. 8) and the tensioner device 820 may include a first pulley 824 that is adapted to drive, or be driven by, the belt.

[0064] The tensioner device 820 shown in FIG. 8 may be used to apply tension to multiple runs of the belt. For example, the tensioner device 820 may include multiple pulleys that are each adapted to engage and tension the belt using one or more biasing elements of the tensioner device 820. To facilitate the foregoing, in the example of FIG. 8, the tensioner device 820 includes a first rotary arm 840, a second rotary arm 844, a second pulley 828, a third pulley 832, and a biasing element 836. As shown in greater detail in FIG. 9, the first and second rotary arms 840, 844 are connected to the rotatable shaft 808 and the first pulley 824 using one or more coupling features. Broadly, the coupling features may allow the first and second rotary arms 840, 844 to move relative to one another, and relative to the support structure 810. The first and second rotary arms 840, 844 may in turn support other components of the tensioner device 820, such as pulleys, biasing elements, and so on, while floating, rotationally relative to the rotatable shaft 808.

[0065] In the example of FIG. 8, the second pulley 828 is journalled to the second rotary arm 844 and positioned to engage a belt. The second pulley 828 may be journalled to the second rotary arm 844 opposite the association of the second rotary arm 844 and the rotatable shaft 808. Further, the third pulley 832 may be journalled to the first rotary arm 840 and positioned to engage a belt. The third pulley 832 may be journalled to the first rotary arm 840 opposite the association of the first rotary arm 840 and the rotatable shaft 808.

[0066] The biasing element 836 may be adapted to encourage movement of the first and second rotary arms 840, 844 away and/or toward one another. This movement of the rotary arms 840, 844 may be used to manipulate the second and third pulley 828, 832 toward the belt for tensioning the belt. For example, the biasing element 836 may generally extend between the first rotary arm 840 and the second rotary arm 844. In the example of FIG. 8, the biasing element 836 includes a first portion 837a that is connected to the first rotary arm 840. The biasing element 836 also includes a second portion 837b that is connected to the second rotary arm 844. In some cases, as shown in FIG. 8, the biasing element 836 is a helical-type spring with the first portion 837a and the second portion 837b being opposing ends of a coil. In other cases, other biasing elements may be used, including leaf springs and the like. The biasing element 836 may also be integrated with the first pulley 824 and about the rotatable shaft 808, as shown in FIG. 9. As the first and second rotary arms 840, 844 are moved about the rotatable shaft 808 (via the operation of the biasing element 836), the pulleys 828, 832 may move about a tensioner arm axis that may be, in one example, substantially co-linear with an MGU axis 809 and impart a load to the belt for tensioning. It will be appreciated that the characteristics of the biasing element 836, and geometry and arrangement of the pulleys 824, 828, 832 and rotary arms 840, 844 may be tuned in order to tension the belt to a desired value.

[0067] With reference to FIG. 9, a cross-sectional view of the assembly of FIG. 8, taken along line 9-9 of FIG. 8 is shown. As shown in cross-sectional view of FIG. 9, the MGU 804 includes the rotatable shaft 808 with an elongated portion 812, and threads 811b. The rotatable shaft 808 is rotatable about the MGU axis 809, as shown in FIG. 9. A support structure 810 of a housing 805 of the MGU 804 may extend along the rotatable shaft. As further shown in the cross- sectional view of FIG. 9, the tensioner device 820 includes a hub 813, threads 811a and a first engagement surface 829 of the first pulley 824, a nut 814, splines 816, a mounting portion 843 of the first rotary arm 840, a bearing assembly 830, a mounting feature 880a and a hole 881a of the second rotary arm 844, a cap 886, a pin 888, a bearing assembly 834, a mounting feature 880b and a hole 881b of the first rotary arm 840, a cap 889, a pin 890, and a coupling feature 848 with a first surface 850a and a second surface 850b.

[0068] In this regard, the tensioner device 820 may be substantially analogous to the tensioner device 120 of FIG. 5 and the tensioner device 620 of FIG. 6; redundant explanation of which is omitted here for clarity. Notwithstanding the foregoing similarities, the tensioner device 820 further includes a second coupling feature 852. For example, the coupling feature 848 may define a first coupling feature 848, and the second coupling feature 852 may be used to establish movement of the second rotary arm 844 relative to the first rotary arm 840. In the example of FIG. 9, the second coupling feature 852 is shown as a cylindrical bushing that is arranged between the first and second rotary arms 840, 844 and about the rotatable shaft 808. For example, the first rotary arm 840 may define the mounting portion 843 that may be arranged about the rotatable shaft 808, and the second rotary arm 844 may define a mounting portion 847 that may be arranged about the rotatable shaft 808 may defining an annular gap with the mounting portion 843. Within the annular gap, the second coupling feature 852 may be installed with opposing cylindrical surfaces 854a, 854b arranged for contact with the mounting portions 843, 847. In some cases, one or both of the opposing cylindrical surfaces 854a, 854b may be a textured surface or otherwise be tuned to facilitate damping. A retaining ring or other feature may be implemented to impede axial movement of the second coupling feature 852 along the rotatable shaft 808.

[0069] It will be appreciated that while the second coupling feature 852 is shown in FIG. 9 as a cylindrical bushing, other structures are contemplated herein. For example, the second coupling feature 852 may be defined as bearing-type structure. In this regard, the opposing cylindrical surfaces 854a, 854b may be surfaces of a first race and a movable coupled second race of a bearing assembly, as one example.

[0070] As one example modification of the tensioner device 820, a biasing element may be arranged substantially within the first pulley 824. For example, FIG. 10 shows a detail view of an example modification of the tensioner device 820 in which the biasing element 836 is positioned substantially within the first pulley 824 for biasing the first and second rotary arms 840, 844 relative to one another to define an assembly 800'. In the example of FIG. 10, the mounting portion 843 defines a first landing, or surface, 866a. The mounting portion 847 defines a second landing, or surface, 866b. The first portion 837a of the biasing element 836 is seated at the first landing, or surface, 866a and the second portion 837b of the biasing element 836 is seated at the second landing, or surface, 866b. The landings 866a, 866b may catch the respective first and second portions 837a, 837b such that the first portion 837a is generally fixed to the mounting portion 843 of the first rotary arm 840 and the second portion 837b is generally fixed to the mounting portion 847 of the second rotary arm 844. The first and second portions 837a, 837b move relative to one another according to a spring coefficient or other parameter in order to store and release a biasing force responsive to the relative movement. The biasing element 836 may therefore be tuned to bias the first and second rotary arms 840, 844 as the first and second rotary arms 840, 844 move relative to one another. [0071] In some cases, a single coupling feature may be implemented in order to facilitate movement of a pair of rotary arms about a rotatable shaft of an MGU. With reference to FIGS. 11-14, an arrangement 1100 is shown where a coupling feature 1120 is used to engage a first rotary arm 1104 and establish movement of the first rotary arm 1104 relative to a support structure 1140 and a second rotary arm 1150. In this manner, the coupling feature 1120 may be an integrated coupling feature that reduces overall component count and complexity, and thus streamlines manufacturing of a tensioner device.

[0072] Turning to FIG. 11, the coupling feature 1120 and the first rotary arm 1104 are shown in an installed configuration. Broadly, the coupling feature 1120 may have a cylindrical portion 1124. The coupling feature 1120 may also include a series of raised features 1128 extending from the cylindrical portion 1124 and being circumferentially spaced along a perimeter of the cylindrical portion 1124. The cylindrical portion 1124 may be adapted to engage the support structure 1140, which may be a nose or other structural element of an MGU housing. The series of raised features 1128 may be adapted to extend between fingers 1108 of the first rotary arm 1104 for engagement of the second rotary arm 1150. The series of raised features 1128 may the fingers 1108 may therefore be interposed with one another and engaged in a manner that rotationally fixes the coupling feature 1120 and the first rotary arm 1104.

[0073] With reference to FIG. 12, an exploded view of arrangement 1100 is shown. In the exploded view, the rotary arm 1104 is separated from the coupling feature 1120. As shown in FIG. 12, the first rotary arm 1104 includes an arm portion 1106. The arm portion 1106 may generally extend radially from a rotatable shaft of the MGU in an installed configuration. The fingers 1108 are shown in the example of FIG. 12 as extending generally perpendicularly from the arm portion 1106. The fingers 1108 are circumferentially spaced about an opening 1113. The opening 1113 may be adapted to fit over the support structure 1140 or nose of the MGU. The fingers 1108 are circumferentially spaced and separated from one another by through portions 1112. The through portions 1112 are tailored to receive the series of raised features 1128 of the coupling feature 1120.

[0074] For example and as shown in FIG. 12, the coupling feature 1120 is shown as including the series of raised features 1128. The series of raised features are circumferentially spaced about an opening 1129. The opening 1129 may be adapted to fit over the support structure 1140 or nose of the MGU. The series of raised features 1128 are circumferentially spaced and separated from one another by receiving zones 1122. The receiving zones 1122 are tailored to receive the fingers 1108 of the first rotary arm 1104. With the fingers 1108 received by the receiving zones 1122 and the series of raised features 1128 received by corresponding ones of the through portions 1112, the first rotary arm 1104 and the coupling features 1120 may be fixed relative to one another and thus moveable together. In some cases, the coupling feature 1120 may include a gap feature 1132 that extends through an entire axial length of the coupling feature 1120. This may help the coupling feature 1120 flex for installation with the first rotary arm 1104.

[0075] As described herein, the coupling feature 1120 may be adapted to facilitate movement of the first rotary arm 1104 relative to the support structure 1140 and the second rotary arm 1150. In this regard, the series of raised features 1128 may include a textured surface 1130 that is adapted for contact with the second rotary arm 1150. Further, the cylindrical portion 1124 may include a textured surface 1126 that is adapted for contact with the support structure 1140. The series of raised features 1128 may contact the second rotary arm 1150 with the textured surface 1130 and facilitate movement of the second rotary arm 1150 along a direction n, as shown in FIG. 13. The textured surface 1130 may be tuned to generate a friction torque relative to the second rotary arm 1150. Further, the cylindrical portion 1124 may contact the support structure 1140 with the textured surface 1126 and facilitate movement of the first rotary arm 1104 along a direction n. The textured surface 1140 may be tuned to generate a friction torque relative to the first rotary arm 1104.

[0076] With the arrangement 1100, the coupling feature 1120 operates to allow rotation of the second rotary arm 1150 without transferring a hub load of the second rotary arm 1050 to the first rotary arm 1104. For example, FIG 14 depicts a cross-sectional view of the arrangement 1100 of FIG. 11, taken along line 14-14 of FIG. 11. During operation, the first rotary arm 1104 may exhibit a hub load Fi and the second rotary arm 1150 may exhibit a hub load F2. As shown in the example of FIG. 14, the hub load Fi may be transferred to the coupling feature 1120 via the engagement of the fingers 1108 and the receiving zones 1122. As further shown in FIG. 14, the hub load F2 may be transferred to the coupling feature 1120 via the engagement of the second rotary arm 1150 and the series of raised features 1128. The coupling feature 1120 may receive the hub loads Fi, F2 and transfer the respective loads to the support structure 1140. Accordingly, the fingers 1108 may not receive the hub load F2. This may prevent component wear, and allow the first and second rotary arms 1104, 1150 to move relative to one another with less impediment from hub loads during operation of the assembly.

[0077] Other examples and implementations are within the scope and spirit of the disclosure and appended claims. For example, features implementing functions may also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations. Thus, the foregoing descriptions of the specific examples described herein are presented for purposes of illustration and description. They are not targeted to be exhaustive or to limit the examples to the precise forms disclosed. It will be apparent to one of ordinary skill in the art that many modifications and variations are possible in view of the above teachings.