POWERED DRIVE UNIT WITH INTEGRATED COUNTERBALANCE

A powered actuator for moving a motor vehicle closure member from a closed position to an open position and method of facilitating movement of the closure member therewith. Powered actuator includes an electric motor configured to rotate a driven shaft and a gearbox coupled to the driven shaft. An extensible member extends through the gearbox to a proximal end on one side of the gearbox for attachment to one of a vehicle body or the closure member and to a distal end on an opposite side of the gearbox. Extensible member is configured to move between retracted and extended positions in response to rotation of the driven shaft. A bias member is configured to impart an axially directed bias on the extensible member to facilitate controlled movement of the extensible member, while reducing the load imparted on the electric motor and the gearbox during powered movement of the closure member between the open and closed positions.

FIELD

The present disclosure relates to a power actuator for a vehicle closure. More specifically, the present disclosure relates to a power actuator assembly for a vehicle closure member.

BACKGROUND

Closure members of motor vehicles may be mounted by one or more hinges to the vehicle body. For example, tailgates, passenger doors, and rear hatches may be oriented and attached to the vehicle body by the one or more hinges for swinging movement about a pivot axis. In such an arrangement, each door hinge typically includes a closure member hinge strap connected to the closure member, a body hinge strap connected to the vehicle body, and a pivot pin arranged to pivotably connect the closure member hinge strap to the body hinge strap and define a pivot axis. Such swinging closure members may be moveable by power closure member actuation systems. Specifically, the power closure member system can function to automatically swing the closure member about its pivot axis between the open and closed positions, to assist the user as the user moves the closure member, and/or to automatically move the closure member between closed and open positions for the user.

Typically, power closure member actuation systems include a power-operated device such as, for example, an electric motor and a rotary-to-linear conversion device that are operable for converting the rotary output of the electric motor into translational movement of an extensible member. The electric motor and the conversion device are typically mounted to the closure member and an end of the extensible member is typically secured to the vehicle body. One example of a power closure member actuation system for a passenger door is shown in commonly-owned International Publication No. WO2013/013313 to Scheuring et al. which discloses use of a rotary-to-linear conversion device having an externally-threaded leadscrew rotatively driven by the electric motor and an internally-threaded drive nut meshingly engaged with the leadscrew and to which the extensible member is attached. Control over the speed and direction of rotation of the leadscrew results in control over the speed and direction of translational movement of the drive nut and the extensible member for controlling swinging movement of the closure member between its open and closed positions. The entire force provided to move the closure member between its open and closed positions is provided by the electric motor. Although suitable for its intended function, the size of the electric motor must be sufficiently large to provide the force needed to move the closure member between its open and closed positions. Further yet, the stress applied to the electric motor by counteracting forces from the closure member, including excess forces generated by wind and gravity, can cause accelerated wear to the electric motor and other components, including the drive nut and leadscrew, thereby diminishing the useful life of the power closure member actuation system.

In view of the above, there remains a need to develop power closure member actuation systems which address and overcome limitations and drawbacks associated with known power closure member actuation systems as well as to provide increased convenience and enhanced operational capabilities.

SUMMARY

This section provides a general summary of some of the objects, advantages, aspects and features provided by the inventive concepts associated with the present disclosure. However, this section is not intended to be considered an exhaustive and comprehensive listing of all such objects, advantages, aspects and features of the present disclosure.

In one aspect, the present disclosure is directed to a vehicle closure panel and a powered actuator for the vehicle closure panel which advances the art and improves upon currently known vehicle closure panels and powered actuators for such vehicle closure panels.

In another aspect, the present disclosure is directed to a method of constructing a powered actuator for a closure panel of a motor vehicle which advances the art and improves upon currently known methods of constructing powered actuators for vehicle closure panels.

In accordance with these and other aspects, a powered actuator for moving a closure member of a motor vehicle between a closed position and an open position includes an electric motor configured to rotate a driven shaft. A gearbox is coupled to the driven shaft. A gearbox housing encloses the gearbox. An extensible member extends through the gearbox and has a proximal end on one side of the gearbox and a distal end on an opposite side of the gearbox. The distal end is configured to be pivotably coupled to one of a vehicle body or the closure member. The extensible member is configured to move between a retracted position, corresponding to the closed position of the closure member, and an extended position, corresponding to the open position of the closure member, in response to rotation of the driven shaft. A bias member is configured to impart an axially directed bias on the extensible member to facilitate controlled axial movement of the extensible member, while reducing the load imparted on the electric motor and the gearbox during powered movement of the closure member between the open and closed positions.

In accordance with another aspect of the disclosure, the bias member is in a compressed state when the extensible member is in one of the retracted position or the extended position, and wherein the bias member is in a decompressed state when the extensible member is in the other of the retracted position or the extended position.

In accordance with another aspect of the disclosure, the bias member can be configured to be in the compressed state when the extensible member is in the retracted position, whereat the bias member exerts a bias on the extensible member to facilitate moving the closure member from the closed position to the open position.

In accordance with another aspect of the disclosure, the bias member can be disposed between the gearbox housing and the distal end of the extensible member.

In accordance with another aspect of the disclosure, the bias member can be provided as a coil spring disposed about the extensible member.

In accordance with another aspect of the disclosure, the bias member can be configured to be in the compressed state when the extensible member is in the extended position, whereat the bias member exerts a bias on the extensible member to facilitate supporting weight of the closure member as the closure member moves from the closed position toward the open position.

In accordance with another aspect of the disclosure, the bias member can be disposed between the gearbox housing and the proximal end of the extensible member.

In accordance with another aspect of the disclosure, a motor vehicle having a closure member moveable between open and closed positions has a powered actuator for moving the closure member between the closed position and the open position. The powered actuator includes an electric motor configured to rotate a driven shaft, a gearbox coupled to the driven shaft, an extensible member extending through the gearbox and having a proximal end on one side of the gearbox and a distal end on an opposite side of the gearbox. The distal end is configured to be pivotably coupled to one of a vehicle body of the motor vehicle or the closure member. The extensible member is configured to move between a retracted position relative to the gearbox, corresponding to the closed position of the closure member, and an extended position relative to the gearbox, corresponding to the open position of the closure member, in response to rotation of the driven shaft. A bias member is arranged to impart an axially directed bias on the extensible member to facilitate controlled axial movement of the extensible member, while reducing the load imparted on the electric motor and the gearbox, during powered movement of the closure member between the open and closed positions.

In accordance with another aspect of the disclosure, a method of facilitating movement of a closure member between and open position and a closed position with a powered actuator having an electric motor configured to rotate a driven shaft is provided. The method includes coupling a gearbox to the driven shaft; enclosing the gearbox with a gearbox housing; extending an extensible member through the gearbox with a proximal end of the extensible member being on one side of the gearbox and a distal end of the extensible member being on another side of the gearbox; configuring the distal end to be pivotably coupled to one of a vehicle body or the closure member; configuring the extensible member to move in response to rotation of the driven shaft between a retracted position, corresponding to the closed position of the closure member, and an extended position, corresponding to the open position of the closure member; and imparting an axially directed bias on the extensible member with a bias member to facilitate controlled axial movement of the extensible member between the retracted and extended positions.

In accordance with another aspect of the disclosure, the method can further include providing the bias member being configured to be compressed as the closure member is moved toward the open position.

In accordance with another aspect of the disclosure, the method can further include providing the bias member being configured to be compressed as the closure member is moved toward the closed position.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

One or more example embodiments of a powered closure member of the type well-suited for use in motor vehicle closure systems will now be described with reference to the accompany drawings. However, these example embodiments are only provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail, as they will be readily understood by a skilled artisan.

Referring initially toFIG.1A, an example motor vehicle10is shown to include a closure member12, illustrated as a tailgate, by way of example and without limitation, pivotally mounted to a vehicle body14via a pair of hinges16,18which are shown in phantom lines. In accordance with the present disclosure, a power closure member actuation system20includes a power drive unit, also referred to as power-operated actuator mechanism or actuator22pivotally connected between closure panel12and the vehicle body14. In accordance with a preferred configuration, power-operated actuator mechanism or actuator22is disposed and secured within an internal cavity of closure panel12, and a rotary drive mechanism that is driven by the power-operated actuator mechanism22is drivingly coupled to the vehicle body14. The internal cavity23is illustratively defined by inner25and outer panels27of the closure panel. Driven rotation of the rotary drive mechanism causes controlled pivotal movement of passenger door12relative to vehicle body14. In accordance with this preferred configuration, the power-operated actuator mechanism22is pivotally coupled to the closure panel12between hinges16,18, while the rotary drive mechanism is pivotally coupled to the vehicle body14. However, those skilled in the art will recognize that alternative packaging configurations for power closure member actuation system20are available to accommodate available packaging space. One such alternative packaging configuration may include mounting the power-operated actuator mechanism22to vehicle body14and drivingly interconnecting the rotary drive mechanism to the closure panel12.

As best shown inFIGS.2A and2B, power-operated actuator mechanism22has a motor and geartrain assembly34that is connectable to closure member12. Motor and geartrain assembly34is configured to generate a rotational force about pivot axis A. In the preferred embodiment, motor and geartrain assembly34includes an electric motor36that is operatively coupled to a speed reducing/torque multiplying assembly38, as a gearbox having one or more stages with a gear ratio allowing motor and geartrain assembly34to generate a rotational force having a high torque output by way of a very low rotational speed of electric motor36. However, any other arrangement of motor and geartrain assembly34can be used to establish the required rotational force without departing from the scope of the subject disclosure. Electrical motor36is controlled by electronics, which may include a microprocessor110and power electronics92, such as H-bridge, FETS for example, controlled by the microprocessor110, as disclosed in co-owned U.S. patent application Ser. No. 17/206,198, published as Publication No. 2021/0293071 (the '071 publication), Sep. 23, 2021, which is incorporated by way of reference in its entirety herein.

Motor and geartrain assembly34includes a mounting bracket40for establishing the connectable relationship with closure member12and the actuator22, as thoroughly discussed in the '071 publication. Power closure member actuation system20further includes the rotary drive mechanism that is rotatively driven by the power-operated actuator mechanism22.FIGS.2A and2Bshow the general arrangement of the gearbox38, which is configured to drive an extensible member134between a retracted position (FIG.2A), whereat closure member12is moved to its closed position, and an extended position (FIG.2B), whereat closure member12is moved to its open position.

Gearbox38includes a lead nut (shown in appended '071 publication) disposed in threaded engagement with the extensible member134that is formed as a leadscrew. Extensible member134is driven by rotation of the lead nut such that the lead nut remains fixed against axial translation relative to the gearbox38, while the extensible member134translates linearly through gearbox38when lead nut is rotated, such that extensible member134translated linearly relative to the gearbox38between its retracted and extended positions.

A cover302, broken away and partially illustrated inFIGS.2A and2Bfor clarity purposes only, is attached to the gearbox38and is configured to enclose the extensible member134on one side of gearbox38to prevent contamination from reaching extensible member134. The cover302is formed as a hollow tubular member, such as having a cylindrical geometry or otherwise. The cover302is illustratively a light weight non-load bearing structure for supporting the weight of the gearbox140and motor36, and in other words, the cover302does not support the weight of the motor36and/or gearbox140. Cover302may be made from rubber, plastic, or a lightweight metal, such as aluminum, for example.

The power-operated actuator mechanism22includes an integrated counterbalancing bias member, referred to hereafter as bias member500, configured to impart an axially directed bias on extensible member134along a longitudinal along axis A1of extensible member134to facilitate controlled axial movement of extensible member134, thereby reducing the load imparted on electric motor36and gearbox38during powered movement of closure member12. Accordingly, the effort (power) required by electrical motor36to effect movement of extensible member134is reduced, thereby being able to reduce the size, weight, and cost of electric motor36.

The bias member500is in a compressed state, corresponding to an energy storing state), when the extensible member134is in one of the retracted position or the extended position, and the bias member500is in a decompressed state (corresponding to an energy exhausted state), when the extensible member134is in the other of the retracted position or the extended position. In accordance with one aspect, as shown inFIG.2A, the bias member500is in the energy dissipated, decompressed state when the extensible member134is in the retracted position, whereat the closure member, shown as tailgate12, is in the closed position. Meanwhile, as shown inFIG.2B, the bias member500is moved to the energy storing, compressed state when the extensible member134is in the extended position, whereat the closure member, shown as tailgate12, is in the open position. While moving toward, and while in the compressed state, the bias member500exerts a counterforce F1(bias), acting in an opposite direction to a force (weight) generated by gravity acting on closure member12, on the extensible member134to facilitate supporting the weight of the closure member12, such as tailgate ofFIG.1A, as the closure member12moves from the closed position (vertically upright) toward the open position (horizontal), and while closure member12is in its fully open position. The counterforce F1acts to reduce the load applied on the gearbox38and on the electric motor36, thereby increasing their operating efficiency and extending their useful life, as discussed above.

As shown inFIGS.2A and2B, the bias member500is disposed between the gearbox housing141and the proximal end316of the extensible member134. The bias member500can be provided as a generally cylindrical coil spring disposed about the extensible member134, with one end500aof the bias member500being biased into engagement with the gearbox housing141and an opposite end500bof the bias member500being operably fixed to the extensible member134, shown as being operably fixed to the extensible member134via an end stop, such as a fixed washer W, adjacent to or at the proximal end316. Bias member end500bis maintained in abutment with end stop W as a result of bias member500being compressed from its fully relaxed stated between end stop W and gearbox housing141, even when bias member500is in its decompressed state. Accordingly, even when bias member500is in its decompressed stated, a slight load is applied along bias member500to keep it from being in a fully decompressed, relaxed state, thereby eliminating a source of rattle and noise generation.

In accordance with another aspect, example motor vehicle110has a closure member112, shown as a liftgate, by way of example and without limitation, pivotally mounted to a vehicle body114via a pair of hinges116,118and supported for pivotal movement about a pivot axis PA between closed and open positions by a power-operated actuator mechanism122. As liftgate112is moved toward its open position, actuator122must exert and sustain a force sufficient to support and push the weight of liftgate112upwardly against a downward acting gravitational force on liftgate112. To facilitate exerting and sustaining such force, as shown inFIG.3A, a bias member500′ of actuator122is in the energy storing, compressed state when the extensible member134is in the retracted position, whereat the closure member112is in the closed position. Accordingly, while closure member112is closed, bias member500′ is compress and loaded to exert a bias force F1directed along a direction tending to assist in moving closure member112toward its open position. As shown inFIG.3B, the bias member500′, shown schematically, is moved to its energy dissipated, decompressed state when the extensible member134is in the extended position, whereat the bias member500′ exerts a bias F1on an end stop, such as a washer W, and on gearbox housing141, thereby applying force F1on the extensible member134to facilitate holding the closure member112in the open position against the downwardly acting gravitational force. It is to be recognized that as extensible member134is moving from its retracted position toward its extended position under powered actuation by electric motor36, the bias member500′ exerts bias force F1on extensible member134, thereby assisting electric motor36in moving liftgate112toward its open position, and thus, reducing the output load needed from electric motor36to perform the opening movement of liftgate112.

As shown inFIGS.3A and3B, the bias member500′ is disposed between the gearbox housing141and the distal end314of the extensible member134. The bias member500′ can be provided as a coil spring disposed and wrapped helically about the extensible member134, as discussed above for bias member500, with one end500aof the bias member500′ being biased into engagement with the gearbox housing141and an opposite end500bof the bias member500′ being operably fixed to the extensible member134, shown as being fixed in abutment with end stop W, thereby being operably fixed to extensible member134adjacent to or at the distal end314. As discussed above for bias member500, bias member500′ is maintained under a slight axial compression even when in its decompress state, thereby eliminating a potential source of rattle and noise.

FIG.4illustrates a method1000of facilitating movement of a closure member12,112between an open position and a closed position with a powered actuator22,122having an electric motor36configured to rotate a driven shaft166. The method1000includes coupling a gearbox38to the driven shaft166and enclosing the gearbox38with a gearbox housing141. Further, a step1100of extending an extensible member134through the gearbox38with a proximal end316of the extensible member134being on one side of the gearbox38and a distal end314of the extensible member134being on an opposite side of the gearbox38. Further, configuring the distal end314to be pivotably coupled to one of a vehicle body14or the closure member12and configuring the extensible member134to move in response to rotation of the driven shaft166between a retracted position, corresponding to the closed position of the closure member12,112, and an extended position, corresponding to the open position of the closure member12,112. Further, a step1200of providing and imparting an axially directed bias on the extensible member134with a bias member500,500′ to facilitate controlled axial movement of the extensible member134between the retracted and extended positions. The controlled axial movement of the extensible member134can be facilitated by assisting movement of the extensible member134in the intended direction, or resisting axial movement of the extensible member134in an unintended direction. The method1000can further include a step1300of providing the bias member500being configured to be compressed (FIG.2B) as the closure member12is moved toward, and to the open position. The method1000can further include a step1400of providing the bias member500being connected between the gearbox housing141and an end stop W of the extensible member134. Otherwise, instead of step1300, the method1000can include a step1250of providing the bias member500′ being configured to be compressed (FIG.3A) as the closure member112is moved toward and to the closed position.