Continuous velocity joint with disconnect device

Abstract

A continuous velocity joint assembly includes a rotatable input end and a rotatable output end. A continuous speed mechanism is also provided that allows power to be transferred between an input and an output while allowing angular variation. The disconnect device has a first portion and a second portion that are rotatable relative to each other in a disconnected state and non-rotatable relative to each other in a connected state. The electromechanical actuator switches the disconnect device between a disconnect state and a connected state whereby power is transferred between the input and the output in the connected state and no power is transferred between the input and the output in the disconnect state.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is based on and claims the benefit of U.S. Provisional Application Serial No. 63 / 540,840, filed on September 27, 2023, entitled “Continuous Velocity Universal Joint with Disconnection Device” and U.S. Provisional Application Serial No. 63 / 541,134, filed on September 28, 2023, entitled “Continuous Velocity Universal Joint Disconnected by Flange Interface”. Both of the above applications are fully incorporated herein by reference for all purposes. Technical Field

[0003] The present invention relates generally to drivetrains of vehicles and, more particularly, to wheel-end disconnect assemblies for engaging and disengaging wheels thereof. Background Art

[0004] Mechanisms for selectively engaging and disengaging drive shafts with wheels of respective vehicles are known. For example, a basic scheme may include a mechanism that utilizes multiple drive shafts in a drive train on a continuous or full-time basis. Drive trains in which drive shafts can be engaged and disengaged as needed or as desired have become increasingly popular in recent years for a variety of reasons. For example, known mechanisms allow a user to manually engage the drive train of a vehicle to the wheels, which typically requires the user to exit the vehicle to accomplish the manual engagement. Additionally, automatic systems are known in which a control system of a vehicle automatically engages and disengages the drive train with the wheels based on driving conditions. However, such mechanisms typically include many complex components and thus can be complex and expensive to manufacture and maintain.

[0005] The present invention recognizes and addresses concerns with prior art structures and methods. Summary of the invention

[0006] One aspect of the present invention provides a continuous velocity universal joint assembly including a rotatable input and a rotatable output. A continuous velocity mechanism is also provided that allows power to be transferred between the input and output while allowing for angular variation. A disconnect device has a first portion and a second portion that are rotatable relative to each other in a disconnected state and are not rotatable relative to each other in a connected state. An electromechanical actuator switches the disconnect device between a disconnected state and a connected state, thereby transferring power between the input and output in the connected state and not transferring power between the input and output in the disconnected state.

[0007] According to some exemplary embodiments, the electromechanical actuator may include a screw-type actuator, such as a lead screw actuator having a lead screw rotatably driven by a motor.

[0008] According to some exemplary embodiments, a state holding mechanism may be provided, which is operable to maintain the disconnect device in at least one of a connected state and a disconnected state in the event of a loss of power to the actuator. The state holding mechanism may include an energy storage element, which is operable to move the disconnect device to a selected state in the connected state and the disconnected state in the event of a loss of power to the actuator. For example, the energy storage element may include a torsion spring (e.g., a clock spring) to rotate the lead screw via stored energy. In such an embodiment, the state holding mechanism may be configured to provide a selectable preload to the torsion spring. In some embodiments, a stopper may be provided to maintain the disconnect device in the other of a connected state and a disconnected state in the event of a loss of power to the actuator.

[0009] In some exemplary embodiments, the first portion of the disconnect device may include an outer housing in which a shaft carrying a plurality of trunnions is housed. The second portion of the disconnect device may be positioned axially adjacent to the outer housing, the disconnect device further comprising a clutch mechanism that selectively connects the first portion and the second portion together in a connected state and disconnects the first portion and the second portion in a disconnected state. In addition, the clutch mechanism may include a displaceable collar having splines defined on its inner circumference, at least one of the first portion and the second portion having splines on the outer circumference that are slidably engaged by the splines of the displaceable collar. The displaceable collar in such embodiments may define an annular groove around its outer circumference that is engaged by a fork-shaped member so that the collar can rotate relative to the fork-shaped member, but displacement of the fork-shaped member causes the collar to move axially.

[0010] In some exemplary embodiments, the first portion of the disconnect assembly may include an annular member attached to a rotatable housing in which a shaft carrying a plurality of trunnions is housed. The annular member may have a plurality of radial protrusions spaced about its periphery, each of the radial protrusions defining an axial through hole in which an elongated fastener is housed.

[0011] According to another aspect, the present invention provides a disconnect device for use with a continuous velocity universal joint. The disconnect device includes a first portion and a second portion that are capable of relative rotation relative to each other in a disconnected state and are not capable of relative rotation relative to each other in a connected state. The first portion is configured to be fixed to an outer housing of the continuous velocity universal joint. The second portion is configured to be connected to a source of rotating power. An actuator is also provided to switch the disconnect assembly between a disconnected state and a connected state. As a result, power is transmitted between the second portion and the first portion in the connected state, and no power is transmitted between the second portion and the first portion in the disconnected state.

[0012] In some exemplary embodiments, the first portion is configured to be fixed to the flange of the outer shell of the continuous velocity universal joint. The first portion may, for example, define a plurality of angularly spaced protrusions that define corresponding axial through holes to facilitate fixing the first portion to the flange of the continuous velocity universal joint.

[0013] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate one or more embodiments of the present disclosure and, together with the description, serve to explain the principles of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] A full and enabling disclosure of the invention, including the best mode thereof, to one of ordinary skill in the art is set forth in the specification, which refers to the accompanying drawings, in which:

[0015] Figure 1 is a diagram of a half-shaft assembly according to the prior art;

[0016] Figure 2 yes Figure 1 an enlarged view of one of the continuous velocity universal joints (CVJs) of the half shaft assembly;

[0017] Figure 3 is a schematic diagram of a CVJ with disconnect capability according to an embodiment of the present invention;

[0018] Figure 4 yes Figure 3 , further illustrating an actuator for axially moving the CVJ between a connected state and a disconnected state;

[0019] Figure 5 and Figure 6 Shows the disconnected and connected states respectively. Figure 3 Embodiments of

[0020] Figure 7 is an isometric view of a CVJ with disconnect capability according to an embodiment of the present invention;

[0021] Figure 8 yes Figure 7 A cross-sectional view of a CVJ showing certain internal components;

[0022] Fig. 9 yes Figure 7 an enlarged partial exploded view of a portion of an actuator housing of a CVJ;

[0023] Fig. 10A , 10B and 10C show components of an actuator for implementing a monostable or bistable system;

[0024] Fig.11A and Fig. 11B shows a disconnect function diagram, which shows Figure 7 operational aspects of the CVJ;

[0025] Fig. 12A and Fig. 12B shows a connection function diagram, which shows Figure 7 operational aspects of the CVJ;

[0026] Fig.13 is a cross-sectional view showing aspects of an actuator for implementing a bistable system;

[0027] Fig.13A and 13B Shows Fig.13 components of an actuator;

[0028] Fig.14 is an isometric view of a disconnect assembly for a CVJ having a flange interface; and

[0029] Fig.15 yes Fig.14 An exploded view of the disconnect assembly showing its various components.

[0030] Repeat use of reference characters in the present specification and drawings is intended to represent the same or analogous features or elements of the invention according to the present disclosure. DETAILED DESCRIPTION

[0031] Reference will now be made in detail to the currently preferred embodiments of the present invention, one or more examples of which are shown in the accompanying drawings. Each embodiment is provided by way of explanation rather than limitation of the present invention. In fact, it will be apparent to those skilled in the art that modifications and variations may be made to the present invention without departing from the scope and spirit of the present invention. For example, features shown or described as part of one embodiment may be used in another embodiment to produce yet another embodiment. Therefore, the present invention is intended to cover these modifications and variations within the scope of the appended claims and their equivalents.

[0032] As background, Figure 1A prior art vehicle half-shaft assembly 10 is shown, which may be modified in accordance with the principles of the present invention. The half-shaft 10 includes a first continuous velocity joint 12 and a second continuous velocity joint 14 near respective ends thereof. As is well known, CVJs (also known as "constant velocity joints") are used to transfer rotation from an input shaft to an output shaft when the angle between the shafts varies within a certain range. In this case, the CVJ 12 is considered to be an "inboard" CVJ because the CVJ 12 is directly connected to the differential, for example, via a stub shaft 16. The CVJ 12 transfers torque to an intermediate axle 18, which serves as the input end of the CVJ 14. The CVJ 14 is considered to be an "outboard CVJ" because the CVJ 14 is connected to the wheels to be driven, for example, via an output stub shaft 20. CVJs 12 and 14 have respective shrouds 22 and 24 extending between the outer housings (or simply "outer") of the CVJs 12 and 14 and the shaft 18 to allow angular movement while containing lubricant and protecting the interior of the CVJs from environmental contaminants.

[0033] Now refer to Figure 2 , the inboard CVJ 12 is typically configured as a "slot-type CVJ," meaning that the inboard CVJ 12 accommodates a degree of axial movement relative to the axle 18. Slot-type CVJs have a "tripod" 26 splined to the axle 18, the tripod having three trunnions (such as the trunnion shown at 28) extending radially and spaced 120° apart. Each of these trunnions carries a respective barrel roller bearing that interacts with a CVJ outer portion 32. The shaft 16 extends from the outer portion 32, as shown. Thus, rotation of the shaft 16 rotates the outer portion 32, thereby causing rotation of the tripod 26 and, therefore, rotation of the axle 18. The outboard CVJ may also be a tripod CVJ or any other suitable type, but is typically not a slot-type.

[0034] Embodiments of the present invention provide for selective interruption of power flow through a CVJ (which may be an interposer CVJ or a non-interposer CVJ). The universal joint may be a stand-alone CVJ or a CVJ integrated into a half shaft. (An example of an application for a stand-alone CVJ may be a rear drive propeller shaft) Some embodiments of the present invention achieve selective disconnection of power by utilizing a two-piece external device CVJ that can independently rotate about the same axis when disconnected or rotate together when connected.

[0035] The separation point between the two components of the CVJ external device can be in a number of different positions, some examples of which are shown in the figures discussed below. In order to selectively transmit power between the two, a clutch mechanism is provided. For example, the two components can be selectively coupled in the following manner:

[0036] - A translating ring radially splined to one side and selectively axially splined to the other side.

[0037] - A translating ring radially splined to one side and selectively radially splined to the other side.

[0038] • Radially movable fins that are always in contact with one side and selectively in contact with the other side.

[0039] ●Any other suitable clutch mechanism as needed or desired.

[0040] Use suitable actuators to move translationally or radially movable components, such as:

[0041] • Motor, rack and pinion, and fork.

[0042] • Motor, lead screw and fork.

[0043] ●Motor, half screw and fork.

[0044] ●Plunger solenoid and fork.

[0045] ● Ring-shaped solenoid and ring-shaped armature.

[0046] In the case of a solenoid, a bistable solenoid may be preferably used. A solenoid can be made bistable using, for example, a permanent magnet latch system with a spring or a retractable pen-type mechanism. These bistable options have the benefit of a "failing to state" when the actuator loses power. The retractable pen-type mechanism can also work with a motor-based actuator.

[0047] Lead screw actuator mechanisms traditionally create a naturally stable or naturally unstable assembly to maintain the position of the nut when no power is applied to the motor. In this regard, if the screw is designed to be back-drivable, it will not necessarily maintain the nut position in a given state (e.g., connected, disconnected, or in between). If the screw is designed to be non-back-drivable, the friction in the lead screw allows the nut to maintain position in any state (e.g., connected, disconnected, or in between).

[0048] In the case of disconnect components for drive systems, monostable or bistable systems are generally preferred over constant stable systems. For monostable systems, it is sometimes desirable to have a system that will default back to a known state in the event of a loss of control or loss of power to the actuator motor. This type of system uses continuous power to keep the actuator in one of two desired states. No power is required to keep it in the other state. For bistable systems, it is sometimes desirable to have a system that will remain in a connected state or a disconnected state if the actuator motor loses power, but when the actuator is between connected and disconnected, the system will switch to a known state in the event of a loss of control or loss of power to the actuator motor. The benefit of this type of system is that no power is required to keep the actuator in either of the desired states. If power is removed from the actuator motor, certain embodiments of the present invention achieve functional assurance that the system is always "stationary" in a connected state.

[0049] Figure 3 and Figure 4 A CVJ 512 is shown that can utilize aspects of the present invention. The CVJ 512 is in this case incorporated into a half-axle assembly having a stub shaft 516 for connection to a power source (e.g., a differential or electric drive unit). The CVJ 512 has a housing ("external") having a first portion 532a in which a tripod is located and a second portion 532b to which the stub shaft 516 is secured. Those skilled in the art will appreciate that a sheath extends between the first portion 532a and the axle extending from the tripod. As shown, a collar 550 having axial splines on its inner diameter is located on the outer diameter of the second portion 532b having complementary splines.

[0050] The ball bearing 534 is located on the extension 542 of the second portion 532b. In addition, a thrust bearing 536 may be located between the axially opposing faces of the portions 532a and 532b. The wave spring 552 removes any play in the assembly that could cause noise from the thrust bearing or ball bearing in the disconnected state.

[0051] like Figure 4 As shown, in this embodiment, a fork 554 is used to enable the collar 550 to be in a disconnected position and a connected position (respectively Figure 5 and Figure 6 ) is displaced between the fork 554, which is axially moved by a suitable linear actuator 556, such as a screw-type actuator (e.g., a lead screw actuator). It can be seen that the fork is received in an annular groove extending around the outer circumference of the collar 550, so that the collar 550 can rotate relative to the fork, but the fork can move the collar axially. The collar 550 can, for example, include axial claws or the like to cooperate with suitable openings on the flange 558 of the first part 532a.

[0052] Figure 7 and Figure 8 A CVJ 612 is shown that is similar in many respects to CVJ 512. As shown, the CVJ housing ("external") has a first portion 632a that accommodates a tripod. A second portion 632b is configured to rotate with or independently of portion 632a depending on whether the CVJ 612 is in a connected state or a disconnected state. In this case, the second portion 632b is configured as a hub to accommodate, for example, a short shaft of a differential or an electric drive unit. As shown, portion 632a has an annular extension 660 coaxially positioned with an extension 642 of the second portion 632b. A pair of ball bearings 634a and 634b are located in the radial space between the extensions 642 and 660. An additional ball bearing 634c can be located between the inward extension of the second portion 632b and the environmental housing 662 of the CVJ 612. The first portion 632a carries a drum-shaped wall 664 to separate the area where the tripod is located from the second portion 632b.

[0053] The second part 632b also has a radial flange 670 having a series of axial splines on its outer circumference. The disconnect collar 650 has splines on its inner circumference that engage with the outer splines of the flange 670. The actuator 656, here in the form of a lead screw actuator, axially moves the fork 672. The fork 672 engages the annular groove of the collar 650 so as to convert the collar 650 between the connected position and the disconnected position. In the connected position, the collar 650 engages both the first part 632a and 632b so that they rotate together (i.e., there is no relative rotation). In the disconnected position, the collar 650 is retracted from the second part 632b. Therefore, the first part 632a can rotate at the wheel speed independently of the rotation of the second part 632b.

[0054] The actuator 656 includes a motor 674 that rotates a lead screw 676. The disconnect fork 672 includes an integral nut portion 678 that moves axially when the lead screw 676 rotates. The direction of rotation determines whether the nut portion 678 (and the disconnect fork 672 as a part thereof) moves forward or reverse. The lead screw 676 is supported for rotation by ball bearings 680a-b, as shown.

[0055] Now also refer to Fig. 910, an embodiment of the present invention is functionally provided to ensure that if power is removed from the actuator motor 674, the system is always "stationary" in a connected state (and / or disconnected state). In this regard, a mechanism 682 is provided to push the system to a connected state (and / or disconnected state) when the motor power is lost. The mechanism 682 includes a suitable spring, which is preferably preloaded to a selected torque required to keep the mechanism in a biased state (e.g., a connected state). In this embodiment, the spring includes a suitable torsion spring 684. As shown, a "clock spring" can be used for this purpose because such a spring provides the desired function with a minimum axial length. In the actuated (disconnected) state, the spring 684 is wound during actuation due to the rotation of the lead screw 676, thereby increasing the torque feedback on the system. The actuator motor 674 must maintain power to resist the potential energy stored in the spring 684 to return the system to a connected state. (Although the description herein describes the default to a connected state, it will be understood by those skilled in the art that, alternatively, the orientation of the clock spring can be reversed so that the system is kept in a disconnected state when power fails).

[0056] As reference Fig. 9 As can be most easily explained, the mechanism 682 is configured to allow the user to select a preload. In this embodiment, the mechanism 682 includes a cover 686 that is configured to engage a spring 684 to preload the spring 684 when the cover 686 is rotated. (The cover thus acts as a "crank" or "dial" for preloading.) Once the desired preload torque is reached, a bolt 688 is screwed into a corresponding hole in the actuator cover 690 to set the spring in the preload state. As can be seen, the cover 690 defines a boss 692 in which the spring 684 is received so as to engage with the lead screw 676 (or more precisely, an adapter that is an extension of the lead screw in this embodiment). The cover 686 closes the open end of the boss 692. As shown, the cover 686 includes a series of angularly spaced notches 694 that define preload increments. The bolts 688 are each located next to a selected one of a pair of diametrically opposed notches 694.

[0057] Reference now Fig. 10A-C, angled hard stops may be integrated into the mechanism 682 to prevent any situation where the system inadvertently becomes locked in a connected state and unable to drive the lead screw 676 disconnected. In this case, an adapter 696 including a stop feature 698 is positioned on the end of the lead screw 676 so as to become an integral extension of the lead screw 676. The nut portion 678 itself includes a stop feature 700 that is engaged by the stop feature 698 when the nut portion 678 has reached the desired limit of its outward axial travel. Preferably, the stop features 698 and 700 engage at an angle before the body of the nut portion 678 axially contacts the adapter 696. As the nut portion moves axially outward, a suitable spring device, such as a stack of Belleville springs 702, compresses to allow the nut to travel axially without the collar engaging where the deltarpm exceeds the application requirements.

[0058] According to a preferred embodiment, the mechanism 682 can be assembled as follows: (1) the lead screw 676 is rotated counterclockwise, either manually or using the actuator motor 674, until the system is fully actuated into engagement and the nut portion 678 is stopped by the stop feature 698 of the lead screw. (2) The spring 684 and the cover 686 are locked with the locating pin 704 ( Fig. 9 ) to secure the rotation of the outer coil of spring 684 to cover 686. (3) The cover / spring subassembly is then inserted into boss 692 and rotated counterclockwise while monitoring the torque driving the rotation until the desired preload in the spring is achieved. (4) After the desired preload torque is achieved, the rotation is maintained by aligning the notches 694 of cover 686 with the bolt holes in boss 692, and cover 686 is secured in this angular position by bolts 688.

[0059] Fig.11A -B shows the functioning of the system from a connected state to a disconnected state according to a preferred embodiment.

[0060] Fig. 12A -B shows the functioning of the system from a disconnected state to a connected state according to a preferred embodiment.

[0061] Mechanism 682 can provide a bistable function. Fig.13, the nut portion 678' includes an axially extending detent finger 720 that engages with a detent defined in a detent ring 722 at the end of the lead screw 676' opposite the adapter 696, together forming a detent device 724. In this embodiment, the spring 684 holds the actuator in the connected state. After the actuator overcomes the torque of the spring 684 to fully pull the nut portion 678' back to the actuator motor, the detent device 724 holds the actuator in the disconnected state. The retention strength of the detent mechanism 724 should preferably be sufficient to prevent the spring 684 from disengaging it in the presence of shock loads and vibrations (e.g., vehicle vibrations). However, the retention strength should not be so strong that the actuator motor cannot overcome the lock to disengage it when the system is commanded to move to the connected state. The spring 684 drives the actuator from the intermediate state to the connected state.

[0062] Now refer to Fig.14 and Fig.15 It is also desirable to provide a disconnect assembly that is configured to interface with a flanged CVJ connection. Such a disconnect assembly may be utilized in situations where it is not feasible to integrate disconnect capability into the half-shaft assembly at the time of manufacture or in certain other CVJ applications such as retrofits. The disconnect assembly may be monostable or bistable as described above, continuously stable, or even naturally unstable, depending on the needs of the application.

[0063] to this end, Fig.14 and 15 A disconnect assembly 812 constructed in accordance with an embodiment of the present invention is shown. In this case, the disconnect assembly provides a monostable or bistable function similar to the above-described CVJ 612. Components of assembly 812 that are similar to components of CVJ 612 will be identified by reference numerals increased by two hundred.

[0064] The assembly 812 has a first portion 832a that is configured to be coupled to the "exterior" of a CVJ with which it is used (and thus functionally becomes part of the exterior of the CVJ). In this case, the first portion 832a includes a series of angularly spaced radial protrusions 950 that define corresponding through holes 952 that are parallel to the axis of rotation. The plurality of protrusions 950 collectively form a flange interface that will be juxtaposed with the flange of the CVJ. In this regard, the first portion 832a can be secured to the CVJ flange via elongated fasteners (e.g., bolts) that extend through the through holes 952.

[0065] The remaining components can be the same as above Figure 7 and Figure 8The same or similar to those described. In this regard, the second part 832b is configured to rotate with the first part 832a or independently of the first part 832a depending on whether the component 812 is in a connected state or a disconnected state. In this case, the second part 832b is configured as a hub to accommodate, for example, a short shaft of a differential or an electric drive unit. As shown, part 832a has an annular extension 860 coaxially positioned with the extension 842 of the second part 832b. A pair of ball bearings, such as bearing 834a, are located in the radial space between the extension 842 and 860. Additional ball bearings 834c can be located between the inward extension of the second part 832b and the environmental housing 862 of the disconnector 812. The first part 832a carries a drum wall 864 to enclose the second part 832b.

[0066] The second portion 832b has a radial flange 870 having a series of axial splines on its outer circumference. The disconnect collar 850 has splines on its inner circumference that engage with the outer splines of the flange 870. The actuator 856 (here in the form of a lead screw actuator) axially moves the fork 872. The fork 872 engages the annular groove of the collar 850 so as to convert the collar 850 between the connected position and the disconnected position. In the connected position, the collar 850 engages both the first portion 832a and 832b so that they rotate together (i.e., there is no relative rotation). In the disconnected position, the collar 850 is retracted from the second portion 832b. Therefore, the first portion 832a can rotate at the wheel speed independently of the rotation of the second portion 832b.

[0067] The actuator 856 includes a motor that rotates the lead screw. The disconnect fork 872 includes an integral nut portion that moves axially when the lead screw rotates. The direction of rotation determines whether the nut portion (and the disconnect fork 872 as a part thereof) moves in a forward or rearward direction. Annular members 954 and 956 are fixed to the first portion 832a and the second portion 832b, respectively. Members 954 and 956 intersect with each other to provide a labyrinth path between the interior of the housing 862 and the exterior area of ​​the housing 862.

[0068] Although one or more preferred embodiments of the present invention have been described above, it will be apparent to those skilled in the art that various modifications and variations may be made to the present invention without departing from the scope and spirit of the invention.

Claims

1. A continuous velocity universal joint assembly comprising: a rotatable input end and a rotatable output end; a continuous speed mechanism that allows power to be transferred between the input and the output while allowing for angle changes; a disconnect device having a first portion and a second portion, the first portion and the second portion being rotatable relative to each other in a disconnected state and being non-rotatable relative to each other in a connected state; and An electromechanical actuator switches the disconnect device between the disconnect state and the connected state, whereby power is transmitted between the input and the output in the connected state and no power is transmitted between the input and the output in the disconnect state.

2. The continuous velocity universal joint assembly according to claim 1, characterized in that: The electromechanical actuator comprises a screw actuator.

3. The continuous velocity universal joint assembly according to claim 2, characterized in that: The screw-type actuator includes a lead screw actuator having a lead screw rotatably driven by an electric motor.

4. The continuous velocity universal joint assembly according to claim 3, characterized in that: It also includes a state holding mechanism that operates to hold the disconnect device in at least one of the connected state and the disconnected state in the event of a loss of power to the actuator.

5. The continuous velocity universal joint assembly according to claim 4, characterized in that: The state holding mechanism includes a torsion spring that operates to rotate the lead screw via energy stored in the torsion spring to move the disconnect device to a selected state of the connected state and the disconnected state in the event of a loss of power to the actuator.

6. The continuous velocity universal joint assembly according to claim 5, characterized in that: The torsion spring comprises a clock spring.

7. The continuous velocity universal joint assembly according to claim 5, characterized in that: The state maintaining mechanism is configured to provide a selectable preload to the torsion spring.

8. The continuous velocity universal joint assembly according to claim 5, characterized in that: Also included is a detent means for maintaining the disconnect device in the other of the connected state and the disconnected state in the event of a loss of power to the actuator.

9. The continuous velocity universal joint assembly according to claim 1, characterized in that: The first portion of the disconnect device includes an outer housing in which a shaft carrying a plurality of trunnions is housed.

10. The continuous velocity universal joint assembly according to claim 9, characterized in that: The second part of the disconnect device is located axially adjacent to the outer housing, and the disconnect device further includes a clutch mechanism that selectively connects the first part and the second part together in the connected state and disconnects the first part and the second part in the disconnected state.

11. The continuous velocity universal joint assembly according to claim 10, characterized in that: The clutch mechanism includes a displaceable collar having splines defined on an inner circumference thereof, and at least one of the first portion and the second portion having splines on an outer circumference that are slidably engaged by the splines of the displaceable collar.

12. The continuous velocity universal joint assembly according to claim 11, characterized in that: The displaceable collar defines an annular groove around its outer circumference which is engaged by the fork such that the collar can rotate relative to the fork but displacement of the fork causes the collar to move axially.

13. The continuous velocity universal joint assembly according to claim 1, characterized in that: The first portion of the disconnect assembly includes an annular member attached to a rotatable housing in which a shaft carrying a plurality of trunnions is housed.

14. The continuous velocity universal joint assembly according to claim 13, characterized in that: The annular member has a plurality of radial projections spaced about its periphery, each of the radial projections defining an axial throughbore in which an elongated fastener is received.

15. The continuous velocity universal joint assembly according to claim 1, characterized in that: Also included is a state holding mechanism that operates to hold the disconnect device in at least one of the connected state and the disconnected state in the event of a loss of power to the actuator.

16. A disconnect device for use with a continuous velocity universal joint, the device comprising: a first portion and a second portion, the first portion and the second portion being rotatable relative to each other in a disconnected state and being non-rotatable relative to each other in a connected state; The first portion is configured to be secured to an outer housing of the continuous velocity universal joint; The second portion is configured to be connected to a source of rotational power; and An actuator switches the disconnect assembly between the disconnect state and the connect state, thereby transmitting power between the second part and the first part in the connect state and not transmitting power between the second part and the first part in the disconnect state.

17. The disconnect device according to claim 16, characterized in that The first portion is configured to be secured to a flange of the outer housing of the continuous velocity joint.

18. The disconnect device according to claim 17, characterized in that The first portion defines a plurality of angularly spaced apart protrusions defining corresponding axial through-holes for securing the first portion to the flange of the continuous velocity joint.

19. The disconnect device according to claim 16, characterized in that Also included is a state maintaining mechanism that operates to maintain the disconnect device in at least one of the connected state and the disconnected state in the event that power to the actuator is lost.

20. The disconnect device according to claim 19, characterized in that The state holding mechanism includes a torsion spring that operates to rotate the lead screw via energy stored in the torsion spring to move the disconnect device to a selected state of the connected state and the disconnected state in the event that power to the actuator is lost.

21. The disconnect device according to claim 20, characterized in that The torsion spring comprises a clock spring.

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