Patent Application
20070175694
The present disclosure is directed at electromechanical actuators, and more particularly at an actuator for selectively connecting/disconnecting torque delivery.
In recent years, commercial vehicles, sport utility vehicles and passenger vehicles capable of full-time or part-time 4-wheel drive and/or all-wheel-drive operation have become commonplace. In some configurations, the operator has the option of selecting 2-wheel or 4-wheel drive depending on the conditions at any given time. The vehicle may also, or alternatively, be configured to automatically move from one drive train or suspension operating condition to another condition based on road conditions sensed by the vehicle. For example, the vehicle may move from 2-wheel drive to 4-wheel drive, or may selectively drive particular wheels, when slippery road conditions are encountered. Connection and disconnection of a vehicle suspension stabilizer may also be established, either manually or automatically, due to road conditions.
To establish these changes in drive train or suspension operating conditions, a vehicle may be equipped with one or more electromechanical actuators, e.g. for changing the state of the front and/or rear differential, transfer case, and/or stabilizer bar system. Cost and reliability of such actuators are, of course, important considerations. There is thus a continuous need for cost-effective and reliable vehicle gear box shift actuators.
Features and advantages of the present disclosure are set forth by description of embodiments consistent therewith, which description should be considered in conjunction with the accompanying drawings, wherein:
An actuator consistent with the disclosure may suitably be employed in any application for connecting and/or disconnecting two components, e.g., two shafts, etc., for the transmission of torque therebetween. For example, an actuator herein may be employed in connection with the operation of a gear box, such as a transfer case of a 4-wheel drive vehicle, vehicle front differential, vehicle rear differential, transmission, etc. It will be appreciated, however, that an actuator consistent with the disclosure will be useful in connection with a variety of applications in and out of vehicles, such as stabilizer bars, parking brakes, interlocks, etc. It is to be understood, therefore, that illustrated exemplary embodiments described herein are provided only by way of illustration, and are not intended to be limiting.
Referring to
The sleeve 16 may be captured between a return spring 18 and a blocked spline spring 20. The shafts 12, 14 may extend at through central openings in the respective springs 18, 20, as shown. Respective thrust bearings 22, 24 may be disposed between the sleeve 16 and the return spring 18 and the blocked spline spring 20 to permit the sleeve 16 to rotate independently of the springs 18, 20. As shown, in one embodiment, the sleeve 16 and thrust bearings 22, 24 may be at least partially disposed in a non-rotating cage 26. As shown, the thrust bearings 22, 24 may include a plurality of ball bearings. As such, the sleeve 16 may be rotatably disposed within the cage 26 and between the thrust bearings 22, 24. Alternative thrust bearing and/or cage arrangements may be employed for rotatably capturing the sleeve between the return spring and the blocked spline spring.
The actuator 10 may further include an armature 28 and a coil 30. When the coil 30 is energized, the armature 28 may be urged toward the coil 30, e.g. in a manner such as in a conventional solenoid configuration. When the coil 30 is energized to urge the armature 28 toward the coil 30, the armature 28 may urge the sleeve 16 toward the coil 30, e.g., by way of the blocked spline spring 20 acting against the cage 26. The blocked spline spring 20 may be stiffer than the return spring 18, e.g., may have a higher spring constant. Accordingly, absent a blocked condition, when the coil 30 is energized the armature 28 may move the sleeve 16 toward the coil 30, i.e., toward an engaged condition. The blocked spline spring 20 may remain generally uncompressed and/or compressed to a lesser degree than the return spring 18 when the sleeve 16 is moved toward the engaged condition.
The blocked spline spring 20 may provide for initial misalignment of the splines 13, 15 of the shafts 12, 14 when the actuator 10 is energized. For example, if the splines 13, 15 are initially misaligned, the sleeve 16 may be blocked from sliding to at least partially engage the splines 13, 15 of both shafts 12, 14. In such a situation the blocked spline spring 20 may be compressed by the armature 28 as the armature 28 moves toward the coil 30 when the coil 30 is energized. As the shafts 12, 14 rotate relative to one another the respective splines 13, 15 may align with one another, thereby clearing the blocked condition. When the blocked condition is cleared, e.g., by alignment of the splines 13, 15, the blocked spline spring 20 may slidingly drive the sleeve 16 to at least partially engage the splines 13, 15 of each of the shafts 12, 14, thereby coupling the shafts 12, 14 for transmitting torque therebetween.
According to one aspect, the actuator 10 may be maintained in an engaged condition, i.e., with the sleeve 16 coupling the two shafts 12, 14 for transmission of torque therebetween, without requiring a holding current. The actuator may be maintained in an engaged condition using a push-push latching device. In one embodiment, the push-push latching device may include an indexing collar 32 rotatably coupled relative to the armature 28. In an embodiment, the indexing collar 32 may be rotatably coupled to the coil 30. Alternatively, the indexing collar may be coupled to other features, e.g., a housing, of the actuator. The indexing collar 32 may include a series of cam features 34, e.g., double converging cam features as shown, spaced around the circumference of the indexing collar 32. Each cam feature 34 may include a near-side cam face 35 and a far-side cam face 37, as shown in
Referring to
Turning to
The blocked condition spring 20 may bear against the sleeve 16, e.g., via the collar 26, to slidingly drive the sleeve 16 to engage the splines of the shafts 12, 14 to couple the shafts 12, 14 for transmitting torque therebetween. In the event of a blocked condition, the blocked spline spring 20 may remain compressed even after the coil 30 is de-energized, e.g., the engagement of the near-side indexing pin 36 and the cam feature 34, e.g., the engaged pocket 40 of the cam feature 34, may maintain the armature 28 in an engaged condition. When the blocked condition is cleared, e.g., by the alignment of the splines of the shafts 12, 14, the blocked spline spring 20 may slidingly drive the sleeve 16 to engage the splines of both shafts 12, 14 to couple the shafts 12, 14 for transmitting toque therebetween. If not blocked condition exists, the blocked spline spring 20 may drive the sleeve 16 directly to an engaged condition.
The actuator 10 may be disengaged, e.g., to uncouple the shafts 12, 14 from one another to prevent transmitting torque between the two shafts 12, 14. Referring to
With additional reference to
Consistent with the foregoing disclosure, an actuator may be provided for releasably coupling two features, such as shafts, for the transmission of torque therebetween. The actuator may be maintained in an engaged condition without the need for a holding current using a push-push latching device. The push-push latching device may include an indexing feature, such as an indexing collar, and cooperating indexing features associated with an armature. As an actuating coil of the actuator is repeatedly energized the indexing features of the armature may interact with the indexing feature to maintain the armature in an engaged condition or release the armature to a disengaged condition. Accordingly, operation of the actuator may employ simple control electronics, such as a simple momentary switch, for the operation of the actuator. Such an actuator may be compact and low cost to manufacture, and may accommodate blocked condition.
According to one aspect of the disclosure, there is provided an actuator for selectively coupling first and second shafts for transmitting torque between the first and second shafts. The actuator includes a sleeve configured movable between engaged and disengaged positions relative to the first and second shaft, the sleeve coupling the first and second shafts for transmission of torque therebetween in the engaged position and being decoupled from at least one of the first and second shafts in the disengaged position; a coil; an armature responsive to the coil, the armature being configured to force the sleeve into the engaged position upon energization of the coil.
According to another aspect of the disclosure there is provided a system including a first shaft; a second shaft; sleeve configured movable between engaged and disengaged positions relative to the first and second shafts, the sleeve coupling the first and second shafts for transmission of torque therebetween in the engaged position and being decoupled from at least one of the first and second shafts in the disengaged position; a coil; and an armature responsive to the coil, the armature being configured to force the sleeve into the engaged position upon energization of the coil.
Other aspects are set forth in the preceding description and associated drawings. The terms and expressions which have been employed herein are used as terms of description and not of limitation, and there is no intention, in the use of such terms and expressions, of excluding any equivalents of the features shown and described (or portions thereof), and it is recognized that various modifications are possible within the scope of the claims. All such variations and combinations are contemplated within the scope of the present invention. Other modifications, variations, and alternatives are also possible. Accordingly, the claims are intended to cover all such equivalents.
The present application claims the benefit of the filing date of U.S. Provisional Application Ser. No. 60/740,032, filed Nov. 28, 2005, the teachings of which are hereby incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 60740032 | Nov 2005 | US |
