Rotary power transmission device with actuator retention feature

Abstract

A rotary power transmission device includes a housing, a clutch, an actuator, and a retention body. The housing has an annular surface and an interior in which a plurality of members are received for rotation. The clutch is received within the housing and has a clutch ring that is selectively engageable with one of the plurality of members. The actuator has a limiting surface, a coil, and a drive for a plunger that moves along an axis and relative to the clutch, and the plunger is received over and is moveable along the annular surface. The retention body has a blocking surface that radially overlaps the limiting surface and is arranged to be contacted by the limiting surface to prevent removal of the plunger from the annular surface.

Description

[0001] Cross-reference to related applications

[0002] This application claims the rights of U.S. Provisional Application Serial No. 63 / 320,013, filed March 15, 2022, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure generally relates to a rotary power transmission device having an actuator and a retaining feature for at least a portion of the actuator. Background Technology

[0004] Electromagnetic actuators with annular plungers that can be slidably displaced by an electromagnetic field generated by an actuator can be used to actuate a device. A separate holding device is used to maintain the plunger's assembled position, and this holding device is located outside the plunger, increasing the size and complexity of the device. It also requires adjacent components to be located outside the holding device and necessitates additional parts and assembly efforts. Summary of the Invention

[0005] In at least some embodiments, a rotary power transmission device includes a housing, a clutch, an actuator, and a retaining body. The housing has an annular surface and an interior in which a plurality of components are received for rotation. The clutch is received within the housing and has a clutch ring capable of selectively engaging one of the plurality of components. The actuator has a limiting surface, a coil, and a plunger actuated for axial movement relative to the clutch, the plunger being received above and movable along the annular surface. The retaining body has a blocking surface that radially overlaps with and is arranged to contact the limiting surface to prevent the plunger from being removed from the annular surface.

[0006] In at least some embodiments, the coil is received within a coil housing, and a blocking surface is defined by a surface of the coil housing. In at least some embodiments, the blocking surface is defined by a radially inwardly extending protrusion of the coil housing. In at least some embodiments, the protrusion is axially overlapped by the coil. In at least some embodiments, the protrusion is axially offset from the coil. In at least some embodiments, the blocking surface is located radially inside the coil. In at least some embodiments, the blocking surface defines the radially innermost surface of the coil housing.

[0007] In at least some embodiments, the retaining body is supported by an annular surface and extends radially outward from the annular surface. In at least some embodiments, the housing includes a groove extending radially inward from the annular surface, and the retaining body is at least partially annular, partially received within the groove and extending radially out of the groove beyond the annular surface.

[0008] In at least some implementations, the plunger has a first position in which the clutch ring is not engaged with the one of the plurality of members, and the plunger has a second position in which the clutch ring is engaged with the one of the plurality of members. In this arrangement, engagement of the limiting surface with the blocking surface limits movement of the plunger in a direction away from the second position.

[0009] In at least some implementations, the plunger includes a first body and a second body coupled together, the second body including a radially inner surface that slides along the annular surface as the plunger is moved along the annular surface, and a portion of the second body is received radially between the first body and the annular surface, and the limiting surface is defined by the second body.

[0010] In at least some implementations, the plunger includes a first body and a second body coupled together, the second body including a radially inner surface that slides along the annular surface as the plunger is moved along the annular surface, and a portion of the second body is received radially between the first body and the annular surface, and the limiting surface is defined by the first body at a rear end of the plunger opposite a front end of the plunger, wherein the front end of the plunger is engageable with the clutch ring.

[0011] In at least some implementations, a rotary power transmission device includes a housing, a clutch, an actuator, and a retaining body. The housing has an annular surface and an interior in which a plurality of members are received for rotation. The clutch is received within the housing and has a clutch ring that is selectively engageable with one of the plurality of members. The actuator has an annular coil of wire and drives a plunger for movement along an axis and relative to the clutch. The plunger is received over the annular surface and is movable along the annular surface between a first position in which the clutch ring is not engaged with the one of the plurality of members and a second position in which the clutch ring is engaged with the one of the plurality of members. Also, the plunger has a limiting surface that extends radially. The retaining body has a blocking surface that radially overlaps the limiting surface and is arranged to be contacted by the limiting surface when the plunger is in the first position.

[0012] In at least some implementations, the coil of wire is received within a coil housing, and the blocking surface is defined by a surface of the coil housing. In at least some implementations, the blocking surface defines a radially innermost surface of the coil housing.

[0013] In at least some implementations, a groove is provided extending radially inwardly from the annular surface, and the retaining body is an at least partially annular body that is partially received within the groove and extends radially out of the groove beyond the annular surface. BRIEF DESCRIPTION OF DRAWINGS

[0014] The following detailed description of preferred embodiments and best mode will be made with reference to the accompanying drawings, in which:

[0015] Figure 1 This is a schematic diagram of the vehicle's powertrain components;

[0016] Figure 2 This is a cross-sectional view of a differential with an electrically actuated clutch, where the differential is shown in the open position;

[0017] Figure 3 This is a partial cross-sectional view of a clutch component, showing the actuator with a plunger and a solenoid coil;

[0018] Figure 4 yes Figure 3 A magnified partial cross-sectional view of the part;

[0019] Figure 5 This is a partial cross-sectional view of the clutch section, showing the plunger and coil;

[0020] Figure 6 yes Figure 5 A magnified partial cross-sectional view of the part;

[0021] Figure 7 It is a partial perspective view of the housing portion, including the solenoid coil for the actuator, which retains the features;

[0022] Figure 8 It is a partial perspective view of the housing portion including the alternative retaining features;

[0023] Figure 9 This is a partial cross-sectional view of the clutch components, showing the plunger, coil, and plunger retaining features; and

[0024] Figure 10 They have different retention characteristics. Figure 9 A magnified partial cross-sectional view of the part. Detailed Implementation

[0025] Please refer to the attached diagram for more details. Figure 1A vehicle drivetrain 12 is shown, which provides power from an engine 14 to a plurality of wheels including front wheels 15 and rear wheels 16. The engine 14 supplies torque via a transmission 17 and a power transmission unit 18 providing an output shaft 20. The output shaft 20 is coupled to a first driveshaft 21, which is coupled to a rear drive unit 22, which may include a differential assembly 23. The power transmission unit 18 or other device may have an output shaft 24 coupled to a front drive unit 25 (which may include a differential assembly 26) via a second driveshaft 27. A front left axle 28 and a front right axle 29 are coupled to drive units / differentials 25, 26, allowing relative rotation between the side axles 28, 29 and the front wheels 15. A rear left axle 30 and a rear right axle 32 are coupled to the rear drive units / differentials 22, 23, allowing relative rotation between the side axles 30, 32 and the rear wheels 16. The power transmission unit 18 may include a disconnect component that, when in the connected state, transmits torque to the second drive shaft 27 to drive the front wheels 15. When connected or disconnected, the power transmission unit 18 may provide torque to the first drive shaft 21 to drive the rear wheels 16. Thus, depending on the state of the disconnection device, the drivetrain 12 may provide torque only to the rear wheels 16 or to all four wheels 15, 16.

[0026] Of course, other drivetrain configurations can be used as needed. For example, although shown in a rear-wheel drive-based drivetrain, a locking differential can also be used in a front-wheel drive-based all-wheel drive system, or even in a two-wheel drive front-engine / front-wheel drive or front-engine / rear-wheel drive drivetrain, as well as in an electric axle (the final drive unit driven by an electric motor).

[0027] Now refer to Figure 2 The first rear axle 30 is connected to the first side gear 34 within the differential 23. Similarly, the second rear axle 32 is connected to the second side gear 36 within the differential 23. The side gears 34 and 36 are supported within the housing 37 of the differential 23. The differential also includes pinions 38 and 40, which mesh with the side gears 34 and 36 respectively, and are mounted on the pinion shaft 42 within the housing 37.

[0028] For selective locking and unlocking of differential 23, a clutch assembly 46 is provided. The clutch assembly 46 may have an actuated state and a disengaged state, and in one state, the clutch assembly engages one of the side shafts (e.g., 32) to differential housing 37 such that the engaged side shaft rotates with the housing. This, in turn, causes the other side shaft 30 to rotate in unison with housing 37 and the side shaft 32 engaged with housing, so that both side shafts 30, 32 rotate at the same speed.

[0029] In at least some embodiments, the clutch assembly 46 is electrically actuated and includes an actuator having a solenoid 48 with an annular wire coil 49 and a drive component that may include an armature or plunger 54 at least partially received radially inside the coil and overlapping the coil axially. In at least some embodiments, the plunger 54 is also annular, the plunger and coil 49 are arranged coaxially and supported by a housing 37 for rotation with the housing, and a side shaft (here, a second side shaft 32) extends coaxially through a portion of the housing 37, extending through the coil and the plunger. Electrical power is supplied to the coil 49 via a power conductor 50 to generate a magnetic field that displaces the plunger 54 relative to the coil and the differential housing 37 from a first or retracted position to a second or forward position. As explained below, when power is not supplied to the coil 49, a biasing component such as a spring 55 may act on the plunger 54 or on a member engaging with the plunger to facilitate the return of the plunger 54 from the second position to the first position. In at least some embodiments, the clutch assembly 46 is actuated when the plunger 54 is in the second position and disengaged when the plunger is in the first position. Although in the illustrated example the plunger 54 is in its second position when power is supplied to the coil 49 and moves to the first position when power is not supplied to the coil, the reverse can be achieved if desired (e.g., the clutch assembly 46 can be moved to the actuated position by the biasing member 55 and disengaged by supplying power to the coil).

[0030] In at least some embodiments, as described below, the clutch assembly 46 may further include or be associated with a clutch element, referred herein as a clutch ring 56, which is adapted to be driven by a plunger 54 and engage with a side gear 34. The clutch ring 56 may be annular, and portions of the second side gear 36 and / or shaft 32 may extend through the clutch ring. The clutch ring 56 may include a rear end 57 capable of engaging with the plunger 54 and a front end 59 having at least one engagement feature 58, such as a gear or clutch tooth 58 (e.g., a claw-shaped clutch tooth), the at least one engagement feature 58 configured to engage a corresponding engagement feature 60 (e.g., a gear or claw-shaped clutch tooth) formed on the rear end of the first side gear 34. As mentioned above, when the coil 49 is not powered, a spring 55 may act on the clutch ring 56 to urge the clutch ring into the plunger 54 and move the plunger to its first position. In the illustrated embodiment, the plunger 54 is positioned adjacent to one side of the housing wall 62, and the clutch ring 56 is positioned adjacent to the other side of the wall 62. The wall 62 includes an orifice 64, and the plunger 54 and clutch ring 56 each include axially extending feet 66, 68 that extend into or through the orifice 64 in the wall to engage with each other across or through the wall. Like the coil 49 and the plunger 54, the clutch ring 56 is also supported by the housing 37 and rotates with the housing 37.

[0031] Figure 2 The differential 23 shown is depicted in an open mode or position. In the illustrated embodiment, with the differential in the open position, coil 49 is not powered, plunger 54 is in its first position, and clutch ring 56 is not engaged with side gear 34, allowing the side gear to rotate relative to clutch ring 56 and housing 37. In the open position, side shafts 30 and 32 can rotate at different speeds. However, certain driving conditions may make it desirable for side shafts 30 and 32 to rotate uniformly, such that torque is applied to both wheels.

[0032] In the locked position, coil 49 is energized, and plunger 54 advances to its second position, which drives clutch ring 56 to engage with side gear 34 (i.e., teeth 58 and 60 engage and mesh). Therefore, side gear 34 is coupled to housing 37 so that it rotates with housing and not relative to housing. In effect, second side shaft 32 is locked to housing 37 and rotates with housing 37, which in turn forces first side shaft 30 and second side shaft 32 to rotate in unison.

[0033] like Figures 2-6As shown in Figures 9-10, plunger 54 may be formed of a variety of materials, including materials that are magnetically responsive to the magnetic field generated by coil 49, and at least one other material that may or may not be responsive to the magnetic field. Thus, when the magnetic field is generated by coil 49, plunger 54 can be driven from one position to another (e.g., from a retracted position to an advanced position). As used herein, a material responds to the magnetic field if the magnitude of the magnetic field generated by solenoid 48 of the type used in the application (such as the application depicted herein) is such that it can cause displacement of a component formed of or comprising such a material.

[0034] In at least some implementations, such as Figure 2 and Figure 3 As shown, the plunger 54 includes a body having a central axis 73 and may be defined by a first body 74 and a second body 76, which are coupled together and move as a unit or component and do not separate during use. The first body 74 may be formed of a magnetically responsive material and may be received adjacent to and radially inward of the coil 49, with a small air gap between them. The second body 76 may have at least a portion radially inward of at least a portion of the first body 74. The second body 76 may be annular and may radially overlap a portion of the first body 74 in at least some embodiments. The second body 76 may be readily overmolded onto the first body 74 to facilitate the formation of the second body and the connection of the first and second bodies together; however, other forming processes such as, but not limited to, casting, stamping, or extrusion may be used. If desired, the second body 76 may define part or all of a foot 66 of the plunger 54 that may extend axially beyond the first body 74. The second body 76 may be formed of a non-magnetically responsive material (e.g., plastic, aluminum, stainless steel, etc.) and may provide various magnetic flux shielding, which improves the magnetic field strength in or in a region of the first body 74 to ensure proper response of the plunger 54 when the coil 49 is energized. In this way, the magnetic field is more concentrated or stronger in a region of the first body 74 to increase the magnetic flux in or in the first body and improve the response of the plunger 54 to the generated magnetic field.

[0035] like Figure 3 and Figure 4 As shown, the second body 76 may have an inner surface 78, which is received adjacent to or surrounding a surface 79 of the differential housing 37. The inner surface 78 may define a guide diameter for receiving a plunger 54 above the annular surface 79 of the differential housing 37 to guide linear axial movement of the plunger relative to the differential housing.

[0036] Reference Figure 2The clutch ring 56 has a body 80 with a central axis coaxial with the axis 73 of the plunger 54, a radially outer surface 84 extending axially between the rear end 57 and the front end 59, and a radially inner surface 86 having an axial extent smaller than the outer surface 84. The inner surface 86 of the clutch ring 56 can be received as a surface surrounding the side gear 34. A foot 68 of the clutch ring 56 defines a portion of the rear end 57, is circumferentially spaced from the other portions of the rear end 57, and extends axially from the other portions of the rear end 57. Teeth 58 are located on the front end 59. The clutch ring 56 can be made of metals such as alloy steel, chromium steel, chromium-molybdenum steel, nickel steel, nickel-chromium-molybdenum steel, medium / high carbon steel, etc.

[0037] In the use of differential 23, bearing 88 is mounted on the outer surface of the tubular portion 90 of housing 37. Figure 2 In the diagram, bearing 88 is shown in schematic form as a dashed polygon and may include an inner ring having an inner surface on the tubular outer surface of a tubular portion, and an outer ring received above the inner ring. Suitable bearings are known in the art. Figure 2 As shown, as the plunger 54 slides during use, the bearing 88 extends radially beyond the surface 79. The plunger 54 is prevented from sliding out of the housing 37 by engaging with the bearing 88.

[0038] In at least some applications, differential 23 can be assembled to Figure 3 The general configuration shown is such that the clutch ring 56, plunger 54, and coil 49 are in place on the housing 37, but the bearing 88 is not installed. The bearing 88 will be installed later. In this case, the plunger 54 does not overlap with the bearing 88, or is prevented from sliding off the surface 79 by the bearing 88, and the plunger 54 can slide off the surface 79 and disconnect from the housing 37 without any different retaining features.

[0039] exist Figure 3 In the embodiment shown, coil 49 is received within housing 92, which can be made of any suitable material such as various plastics. Housing 92 can be formed from more than one piece to facilitate assembly of coil 49 into housing 92. The housing can be molded above the coil and can be annular, and may completely surround the coil if desired. In at least some embodiments, housing 92 includes or supports plunger retaining features that prevent the plunger from slipping off surface 79 when coil 49 and plunger 54 are mounted on differential housing 37. Figure 3 and 4 In the example shown, the retaining feature is the body or part of the body defining the blocking surface 94, which is engaged by the plunger 54 to restrict the movement of the plunger in a direction away from the clutch ring, preventing the plunger from slipping off the surface 79 and disengaging from the housing 37. Figure 3 and 4In one example, the retaining body is housing 92, and the blocking surface 94 is defined by a protrusion 96 extending radially inward toward plunger 54 and in the path of movement of a portion of plunger 54. In at least some embodiments, the protrusion 96 is axially aligned and overlapped with and by coil 49 and plunger 54, wherein coil 49 is radially outward of protrusion 96. In at least some embodiments, protrusion 96 may define the radially innermost portion of housing 92.

[0040] In the illustrated example, the plunger 54 includes a limiting surface 98 that extends radially outward to partially overlap radially with the blocking surface 94. In the illustrated example, the limiting surface 98 is defined by a portion of the fingers 66 of the plunger 54, which in this example is part of the second body 76 of the plunger 54.

[0041] In at least some embodiments, the radially inner surface 78 of the plunger 54, which slides along the surface 79 of the housing 37, includes a groove 100 in which oil can be received, or the groove 100 further reduces the axial extent of the frictionally engaged inner surface 78 of the housing surface 79 to facilitate sliding movement of the plunger 54 relative to the housing surface 79. The groove 100 is disposed between the opposing front end 102 and rear end 104 of the plunger 54 and defines a first annular guide ring 106 at or near the rear end 104 of the plunger 54, and a second annular guide ring 108 axially spaced from the first guide ring 106, wherein the groove 100 is between them. The first guide ring 106 has an axial dimension, and a blocking surface 94 and a limiting surface 98 are arranged such that the limiting surface 98 contacts the blocking surface 94, while at least a portion of the first guide ring 106 remains overlapping with the housing surface 79. That is, surfaces 94, 98 are in contact with each other before the first guide ring 106 is removed from the surface 79. In at least some implementations, when the plunger foot 66 contacts the clutch ring 56, the distance between the limiting surface 98 and the blocking surface 94 is less than the axial dimension of the first guide ring.

[0042] Even without the bearing 88 or other components required to restrict the movement of the plunger 54, the radially overlapping limiting surface 98 of the plunger 54 and the blocking surface 94 of the coil housing 92 can hold the plunger 54 in the desired assembly position. For example, it is not necessary to install a separate retaining ring or washer on the housing 37 to temporarily hold the plunger 54 until the bearing 88 is installed. Due to the radially overlapping surfaces 94, 98, the plunger 54 cannot be installed on the housing 37 after the coil 49 is installed on the housing 37. Instead, in this example, the plunger 54 is installed on the housing surface 79 before the coil 49 is installed on the housing 37, or the plunger 54 is first installed in the coil 49, and then both the plunger 54 and the coil 49 are positioned together on the housing 37.

[0043] Figures 5-7 This may involve something similar to the above. Figures 2-4 The differential 23 described herein is a differential configuration and arrangement, with differences mentioned herein. For ease of description of this embodiment, the same reference numerals will be used for the same components already described, and the above description is incorporated herein. In this embodiment, the blocking surface 110 of the solenoid coil housing 112 is defined by an inwardly extending protrusion 114 that is axially offset from or outside the coil 49 and does not overlap with the coil 49. The protrusion 114 may be arranged to engage a portion of the rear end 104 of the plunger 54, wherein the rear end can be considered as defining a limiting surface. In at least some embodiments, the protrusion 114 may define a radially innermost portion of the housing 112. In the illustrated example, a portion of the rear end 104 of the first body 74, including the plunger 54, is radially overlapped by the blocking surface 110, but other embodiments may be used. For example, a portion of the rear end 104 of the second body 76 may also be overlapped by the blocking surface 110. With the protrusion 114 offset axially from the coil 49, less housing material is located radially between the coil 49 and the plunger 54. This means there is less material available to reduce or attenuate the magnetic field used to drive the plunger. This improves the actuator's performance.

[0044] Except that the limiting surface (like the limiting surface 98 in the previous embodiment) need not be configured to extend radially beyond the outer diameter of the first body 76, be located at or near the finger 66, or be located elsewhere, the plunger 54 may additionally be constructed as previously described. In at least some embodiments, when the plunger 54 contacts the clutch ring 56, the distance between the limiting surface (which is the rear end 104) and the blocking surface 110 may be less than the axial dimension of the first guide ring 106, or may be additionally arranged to prevent the first guide ring 106 from moving axially away from the housing surface 79.

[0045] Even without the bearing 88 or other components required to restrict the movement of the plunger 54, the radially overlapping limiting surfaces of the plunger 54 (e.g., the portion of the rear end 104) and the blocking surface 110 of the coil housing 112 can hold the plunger 54 in the desired assembly position. For example, it is not necessary to install a separate retaining ring or washer on the housing to hold the plunger 54 until the bearing 88 is installed. Due to the radially overlapping surfaces 104, 110, the plunger 54 cannot be installed on the housing 37 after the coil 49 has been installed on the housing 37. Instead, in this example, the plunger 54 is installed on the housing surface 79 before the coil 49 is installed on the housing 37, or the plunger 54 is first installed in the coil 49, and then both the plunger 54 and the coil 49 are positioned together on the housing 37.

[0046] Figure 8An embodiment is shown in which the radially inwardly projecting portion 116 of the housing 118 is not annular, but rather a discrete portion having a finite circumferential range. For ease of description of this embodiment, the same reference numerals will be used for the same components already described, and the above description is incorporated herein. Several such discrete projecting portions 116 may be provided spaced apart on the housing 118, and one or more, up to all, of the discrete projecting portions 116 provide a blocking surface 119 arranged to engage circumferentially spaced portions of the plunger 54 (e.g., a limiting surface on the plunger, such as a portion of the rear end 104) to retain the plunger 54 on the housing 37 as described above. The discrete projecting portions 116 may be provided as a feature provided during the formation of the coil housing 118, or by deforming the coil housing 118 via crimping, riveting, etc., after it has been otherwise formed.

[0047] Figure 9 and Figure 10 An embodiment is shown in which the plunger retaining feature is defined by a blocking surface 120 extending radially outward from a housing surface 79 over which the plunger 54 moves during use. For ease of description of this embodiment, the same reference numerals will be used for the same components already described, and the above description is incorporated herein. The differential housing 37 includes a channel or recess 122 extending annularly and radially inward from the surface 79, and a retaining body 124 may be disposed within the recess 122. A portion of the retaining body 124 extends radially outward beyond the housing surface 79 and defines the blocking surface 120, which is in the path of a portion of the plunger 54 and arranged to contact the portion of the plunger 54 to retain the plunger 54 in an assembled position. In assembly, the retaining body 124 is axially positioned between guide rings 106, 108 of the plunger 54, aligned with a recess 100 in the plunger 54, and arranged to engage a limiting surface 126 defined by a surface of one of the guide rings (shown as the second guide ring 108).

[0048] In at least some embodiments, the blocking surface 120 is arranged to prevent the plunger 54 from being removed from the housing 37, but does not interfere with the entire range of motion of the plunger 54 in the actuated and de-actuated states of the actuator. Therefore, when the differential is fully assembled and in use, the body 124 and its blocking surface 120 prevent the plunger 54 from being removed from the housing 37, but do not interfere with the entire range of motion of the plunger 54 during differential operation. That is, in at least some embodiments, the limiting surface 126 does not engage the blocking surface 120 when the plunger 54 moves between its first and second positions.

[0049] exist Figure 9In the illustrated example, the retaining body 124 is a partially annular ring, such as a resilient retaining ring, C-clamp, or snap ring, which is partially received within the recess 122 and supported by the differential housing 37 (e.g., supported in or by an annular surface 79 over which the plunger 54 moves during use). The retaining body 124 may have an inner diameter larger than the diameter of the recess 122, allowing compression of the retaining body 124 within the recess 122 when the plunger 54 is mounted above and slides over the retaining body 124. The retaining body 124 is resilient and returns to its uncompressed state after the plunger is mounted. Figure 10 In the example shown, the retaining body 124' is a polymer ring such as an O-ring, which is partially received in the groove 122 and supported by the differential housing 37 (e.g., supported in or by the annular surface 79 over which the plunger 54 moves during use).

[0050] In at least some embodiments, when the plunger contacts the clutch ring, the distance between the limiting surface 126 and the blocking surface 120 may be less than the axial dimension of the first guide ring 106, or may be otherwise arranged to prevent the first guide ring 106 from moving axially away from the housing surface 79. Even without the bearing 88 or other components required to limit the movement of the plunger, the radially overlapping limiting surface 126 of the plunger 54 and the blocking surface 120 of the retaining bodies 124, 124' can hold the plunger 54 in the desired assembled position. For example, it is not necessary to install a separate retaining ring or washer on the housing to temporarily hold the plunger 54 until the bearing 88 is installed.

[0051] The retaining body for the plunger has a blocking surface that restricts the movement of the plunger in the direction of plunger removal from the differential housing. The retaining body may be part of or defined by the housing of the actuator coil, or a body supported by the differential housing. When the actuator is actuated and de-actuated, full movement of the plunger between its first and second positions is permitted, but plunger removal is prevented by the engagement of the plunger limiting surface with the blocking surface. In at least some embodiments, the plunger 54 can be fully movable to and between its first and second positions without contact between the limiting surface and the blocking surface. In at least some embodiments, the contact between the limiting surface and the blocking surface may define either the first or second position of the plunger.

[0052] While the above description relates to locking differential devices, other rotating power transmission devices, such as power take-off units or shaft separators, can utilize clutches with actuators as described herein. In this regard, the power transmission device may include multiple rotating components, such as gears and / or shafts, wherein the clutch and actuator are used to selectively engage at least two of the components to, for example, change the torque flow path through the device. Furthermore, the forms of the invention disclosed herein constitute the currently preferred embodiments, and many other forms and embodiments are possible. It is not intended to refer to all possible equivalents or branches of the invention herein. It is understood that the terminology used herein is descriptive only and not restrictive, and various changes may be made without departing from the spirit or scope of the invention.

[0053] Unless expressly indicated otherwise herein, all terms used in the claims are intended to be given their widest reasonable construction and their ordinary meaning as understood by one of ordinary skill in the art. In particular, unless the claim statement expressly restricts to the contrary, the use of singular articles such as “a,” “the,” “the,” etc., should be read as one or more of the elements indicated in the statement.

Claims

1. A rotary power transmission device comprising: a housing having an interior in which a plurality of members are received for rotation, and wherein the housing has an annular surface; a clutch received within the housing and having a clutch ring that is selectively engageable with one of the plurality of members; an actuator having a coil and a plunger that is driven to move along an axis and relative to the clutch, the plunger being received over and moveable along the annular surface, and the plunger having a limiting surface; and a retaining body having a blocking surface that radially overlaps and is arranged in contact with the limiting surface to prevent removal of the plunger from the annular surface, and wherein the retaining body is supported by the annular surface and extends radially outward of the annular surface, wherein the housing includes a groove located in a portion of the annular surface over which the plunger is received and moveable, and the groove extends radially inward from the portion of the annular surface into the housing, and the retaining body is an at least partially annular body that is partially received within the groove and extends radially out of the groove beyond the annular surface; wherein the plunger includes a radially inner surface that is received over the annular surface, and the radially inner surface is at least partially defined by a first guide ring and a second guide ring that is axially spaced from the first guide ring, and wherein the retaining body is received between the first guide ring and the second guide ring.

2. The apparatus of claim 1, wherein, the plunger has a first position in which the clutch ring is not engaged with the one of the plurality of members, and the plunger has a second position in which the clutch ring is engaged with the one of the plurality of members, and wherein engagement of the limiting surface with the blocking surface limits movement of the plunger in a direction in which the plunger moves away from the second position.

3. The apparatus of claim 1, wherein, the plunger includes a first body and a second body that are coupled together, the second body includes a radially inner surface that slides along the annular surface as the plunger moves along the annular surface, and a portion of the second body is received radially between the first body and the annular surface, and wherein the limiting surface is defined by the second body.

4. A rotary power transmission device comprising: a housing having an interior in which a plurality of members are received for rotation, and wherein the housing has an annular surface; a clutch received within the housing and having a clutch ring that is selectively engageable with one of the plurality of members; an actuator having a toroidal wire coil and a plunger driven to move along an axis and relative to the clutch, the plunger received over the toroidal surface and movable along the toroidal surface between a first position in which the clutch ring is not engaged with the one of the plurality of members and a second position in which the clutch ring is engaged with the one of the plurality of members, and the plunger having a radially extending limit surface; and a retaining body having a blocking surface radially overlapping the limit surface and arranged to be in contact with the limit surface when the plunger is in the first position, and wherein a recess is provided extending radially inwardly from a portion of the toroidal surface into the housing, the plunger being received on the portion of the toroidal surface, and the retaining body being an at least partially toroidal body partially received within the recess and extending radially out of the recess beyond the toroidal surface; wherein the plunger includes a radially inner surface received on the toroidal surface, and the radially inner surface is at least partially defined by a first guide ring and a second guide ring axially spaced from the first guide ring, and wherein the retaining body is received between the first guide ring and the second guide ring.

5. The apparatus of claim 4, wherein, The recess extends along a portion of an axial length of the toroidal surface.

6. A rotary power transmission device comprising: a housing having an interior in which a plurality of members are received for rotation, and wherein the housing has a toroidal surface; a clutch received within the housing and having a clutch ring selectively engageable with one of the plurality of members; an actuator having a toroidal wire coil and a plunger driven to move along an axis and relative to the clutch, the plunger received over the toroidal surface and movable along the toroidal surface between a first position in which the clutch ring is not engaged with the one of the plurality of members and a second position in which the clutch ring is engaged with the one of the plurality of members, and the plunger having a radially extending limit surface; and a retaining body having a blocking surface radially overlapping the limit surface and arranged to be in contact with the limit surface when the plunger is in the first position, and wherein a recess is provided extending radially inwardly from the toroidal surface into the housing, and the retaining body is an at least partially toroidal body partially received within the recess and extending radially out of the recess beyond the toroidal surface, wherein the retaining body radially overlaps the plunger when the plunger is in both the first position and the second position; wherein the plunger includes a radially inner surface received on the toroidal surface, and the radially inner surface is at least partially defined by a first guide ring and a second guide ring axially spaced from the first guide ring, and wherein the retaining body is received between the first guide ring and the second guide ring.

7. The apparatus of claim 6, wherein, The retaining body has an inner diameter greater than a diameter of the recess to enable compression of the retaining body in the recess as the plunger is mounted over the retaining body and slides over the retaining body.

8. The apparatus of claim 6, wherein, Contact between the limiting surface and the blocking surface defines the first position or the second position of the plunger.

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