Patent Description:
Generally, gear assembly actuation is done manually or with the assistance of an actuator. However, most examples have separate actuation assemblies from the fork. In actuators utilizing separate actuation assemblies and forks, the integration of the separate components into a gearbox is complex and application specific, presenting the challenge of utilizing one actuator assembly into several applications.

Typically, the actuation member is configured to linearly move a fork connected with a dog clutch between a plurality of positions. The actuator assembly is operated with a manual force (e.g. a standard gearbox where a user selects gears by moving an actuator from position to position) or with an actuator to move a fork connected with a dog clutch between positions. Given the nature of some gear actuation, when a sliding gear is being moved from a disengaged position into engaged with a receiving gear, there is a momentary blockage or misalignment of gear teeth on the sliding gear and the gear teeth on the receiving gear. In this moment of misalignment, the shift fork is pressing the sliding gear against the receiving gear but the sliding gear is not entering the receiving gear, generating resistance against the fork since the sliding gear teeth and the receiving gear teeth are not aligned. The time window for engagement is typically short due to gear assembly design. If time window is not utilized, a stronger motor is required as force becomes higher to force the teeth of the sliding gear into alignment with the teeth of the receiving gear. This uses a larger force and operates slower, which may not seat the sliding gear into the receiving gear as far, and/or cause premature wear and damage on the system.

It would be attractive to have an actuation system which is low cost with a simple integration into several different systems and types on gearboxes. It would be attractive to have a system which provided fast shifts with low force and high acceleration, preventing damage and premature wear. It would be attractive to have a system with an integrated fork and actuator.

<CIT> discloses an actuator system according to the preamble of claim <NUM>.

<CIT> describes on actuator comprising: a support including an outer surface and an inner surface, with the support having at least one pair of lugs extending from the outer surface of the support, each lug having an opening; a drive system; a shift fork pivotally mounted to the pair of lugs with the shift fork operatively connected to the drive system and configured to move along a distance defining a stroke length between a disengaged position and an engaged position: and an actuation assembly operatively connected with the drive system to move the shift fork between a neutral position, and a shifted position, with a plurality of intermediate positions between the neutral and the shifted position.

The present teachings solve one or more of the present needs by providing an actuator system with low cost, simple integration into a variety of applications, and fast actuation between positions while applying a low force with exceptional penetration.

The present teachings provide for an actuator system comprising a gearbox including a gear assembly, the gearbox having an outer surface, the outer surface with a pair of apertures; and an actuator. The actuator including a support with at least one pair of lugs, with each lug having an opening; a drive system connected to the support; a shift fork including a pair of arms, the shift fork in communication with the drive system and configured to move a distance defining a stroke length between a disengaged position and an engaged position; and an actuation assembly operatively connected with the drive system to move the shift fork between a neutral position, and a shifted position, with a plurality of intermediate positions between the neutral and shifted positions. The actuator is mounted onto the outer surface of the gearbox, with the pair of lugs extending into the pair of apertures of the gearbox, and at least a portion of the shift fork extends extending through the lugs into and below the outer surface of the gearbox. The portion of the shift fork within the gearbox engages a gear assembly within the gearbox. BRIEF DESCRIPTION OF THE DRAWINGS.

The present teachings relate to an actuator <NUM> (also referred to as the actuator system). The actuator <NUM> includes an actuation assembly <NUM> that functions to move at least one shift fork adapted to connect with a dog clutch <NUM> between a disengaged position <NUM> and one or more engaged positions <NUM>. The actuator <NUM> may be attached to a transmission, a transfer case, an axle, a gearbox, a controller, the like, or a combination thereof. The actuator <NUM> may be used in automobiles, autonomous vehicles, robots, trucks, marine vessels, or any other vehicle or machine that utilizes moving gears. The actuator system <NUM> may be used on any device that couples two rotating shafts, gears, or other rotating components. The actuator system <NUM> may be used in conjunction with multiple actuator systems. For example, a transmission may have a first actuator system which actuates a first gear and a second gear, and a second actuator system which actuates a third gear and a fourth gear. It is contemplated in some examples that each actuator system moves a dog clutch <NUM> into communication with one or more receiving gears <NUM>.

The actuator <NUM> is shown in <FIG> and <FIG> in a perspective view. The actuator <NUM> includes a base or a support <NUM> and a housing or a cover <NUM>. The support <NUM> and the cover <NUM> form a cavity therebetween. The housing has a relatively low profile, minimizing the amount of space needed to house the actuator system <NUM>. In some nonlimiting examples, the height of the housing may be less than <NUM>, less than <NUM>, less than <NUM>, or even less than <NUM>. The at least one shift fork <NUM> extends from through the support <NUM>, configured to slide inside of a gearbox and operatively couple with a dog clutch <NUM>. The at least one shift fork <NUM> is pivotally coupled with the support <NUM>. The actuator <NUM> is configured to mount to the surface <NUM> of a gearbox <NUM>, which is shown in <FIG> and partially shown in <FIG>.

The support <NUM> includes at least one pair of lugs <NUM>, each lug extending away from the support <NUM>, having an opening extending from the cavity formed between the support <NUM> and the cover <NUM>. Each of the lugs <NUM> has an opening and an outer surface. The lugs each form a passage from the inner portion of the cavity. The lugs <NUM> may have any suitable shape. In some examples, the lugs <NUM> may have an oval profile, such as shown in <NUM>-<NUM> and 4A-4C. The lugs <NUM> each having a shape to allow the shift fork <NUM> to move between the neutral position and shifted position. The lugs <NUM> assist in mounting the actuator <NUM> to the outer surface <NUM> of a gearbox <NUM>. The lugs <NUM> provide a passage from the cavity for at least a portion of the actuation assembly <NUM> (e.g. fork <NUM>) to pass through into the gearbox <NUM>. Each lug <NUM> is axially disposed around a portion of the shift fork <NUM>. The lugs <NUM> may connect with and provide a pivot point <NUM> to the shift fork <NUM>, described further below. The shift fork <NUM> is pivotally mounted to the pair of lugs <NUM>.

As seen in <FIG>, the gearbox <NUM> have a pair of apertures <NUM> in the surface <NUM> to allow at least a portion of the actuator <NUM> and the shift fork <NUM> to pass into the gearbox <NUM>. The holes on the gearbox are small in order to maintain structural rigidity and strength. Similarly, the shift fork <NUM> is sized to pass through the apertures <NUM> on the surface <NUM> of the gearbox <NUM>. The shift fork <NUM> is shown below a partial view of the gearbox surface <NUM> in schematic <FIG> and <FIG>, while the remainder of the actuator <NUM> is above the surface <NUM> of the gearbox <NUM>. <FIG> illustrates a perspective view of a gearbox <NUM> showing the pair of apertures <NUM> as bosses extending from the outer surface <NUM> of the gearbox. In some examples, the gearbox <NUM> includes a gear assembly <NUM>, configured as a dog clutch assembly, which is illustrated in <FIG> and <FIG>. The apertures <NUM> located on the outer surface <NUM> of the gearbox <NUM> provide passages to receive the shift fork <NUM> and at least a portion of the support <NUM>. The apertures <NUM> function to assist in mounting the actuator <NUM> to the gearbox <NUM>. The apertures <NUM> are shaped to allow the shift fork <NUM> to move between positions <NUM>, <NUM>, <NUM>, in order to shift the gear assembly <NUM>.

<FIG> show the actuator system10 connecting with the gearbox <NUM>. <FIG> depicts the shift fork <NUM> of the actuator system <NUM> aligned with the apertures <NUM>. The lugs <NUM> and the apertures <NUM> have complimentary shapes, the apertures <NUM> sized larger than the lugs <NUM> in order to receive the lugs <NUM>. The apertures <NUM> include a sealing surface <NUM> for mating with the seal <NUM> located around each lug <NUM> and on the bottom surface of the support <NUM>. The sealing surface <NUM> and the seal <NUM> work in concert to keep the actuator <NUM> sealed with the gearbox <NUM> to prevent unwanted particles and debris from entering the gearbox <NUM>, and to prevent fluid from escaping the gearbox. The gearbox <NUM> includes fastener posts <NUM> and the actuator <NUM> includes fastener holes <NUM>. Both the fastener posts <NUM> and the fastener holes <NUM> are axially aligned to receive fasteners to secure the actuator system <NUM> to the gearbox <NUM> when the actuator system <NUM> is connected with the gearbox <NUM>.

<FIG> and <FIG> are partial cross-sectional views of the actuator <NUM> and the gearbox <NUM>. <FIG> shows a partial longitudinal cross-section of the actuator system <NUM> and the gearbox <NUM>. Similarly, <FIG> shows a partial lateral cross-section of the actuator <NUM> and the gearbox <NUM>. The actuator <NUM> passes at least a portion of the shift fork <NUM> and the lugs <NUM> through the outer surface <NUM> of the gearbox <NUM> to connect the shift fork <NUM> with the gear assembly <NUM> (shown in <FIG> and <FIG>). When the actuator <NUM> is connected with the gearbox <NUM>, the lugs <NUM> are disposed within the apertures <NUM>, and the bottom of the support <NUM> and the sealing surface <NUM> press against the seal <NUM>, creating a secured connection. Each seal <NUM> mates with a corresponding seal surface <NUM> on each of the pair apertures <NUM>. The lug <NUM> and the pivot <NUM> can be seen in <FIG> and <FIG> disposed below the surface <NUM> of the gearbox <NUM>. When connected, as shown in <FIG>, the shift fork <NUM> engages the dog clutch <NUM> (also referred to as slider gear) to move the dog clutch <NUM> through positions <NUM>, <NUM>, <NUM> into and out of engagement with receiving gear(s) <NUM>. <FIG> illustrates a close up of the lug <NUM> within aperture <NUM>. The pivot <NUM> is below the outer surface <NUM> of the gearbox <NUM>, disposed within the aperture <NUM>, allowing the shift fork <NUM> to move between positions <NUM>, <NUM>, <NUM>. The lug <NUM> and the bottom of the support <NUM> sealed with the aperture with seal <NUM>. Each of the pair of lugs <NUM> includes seal <NUM> surrounding a perimeter of each of the lugs <NUM>. In some examples, seal <NUM> may be an O-ring. In other examples, seal <NUM> may be a gasket. The seal may be deformable.

<FIG> shows the partial lateral cross-sectional view of the actuator <NUM> and the gearbox <NUM>. <FIG> illustrates a cross-sectional view of the actuator <NUM> connected with the gear assembly <NUM>. As explained further below, the cam assembly <NUM> and actuation assembly <NUM> work to move the dog clutch <NUM> between positions <NUM>, <NUM>, <NUM> by pivoting shift fork <NUM> between positions. <FIG> illustrates the pair of arms of the shift fork <NUM> each disposed within one of the pair of lugs <NUM>, each arm pivotally connected <NUM> to a corresponding lug of the pair of lugs <NUM>. The shift fork <NUM> is shown engaging both sides of the dog clutch <NUM>. The lugs <NUM> and apertures <NUM> are sized and shaped to allow the shift fork <NUM> to move between positions <NUM>, <NUM>, <NUM>. The apertures <NUM> and the lugs <NUM> are spaced apart such that the shift fork <NUM> may pass through the openings, so that the pads <NUM> on the shift fork <NUM> engage either side of the dog clutch <NUM>. The arms of the shift fork <NUM> are spaced apart corresponding to the size of the dog clutch <NUM>. <FIG> is a close-up lateral view of a lug <NUM> retained within the aperture <NUM> with the pivot <NUM> below at least a portion of the outer surface <NUM> of the gearbox <NUM>. In some examples, the pivot connection <NUM> is below the outer surface <NUM> of the gearbox <NUM>.

Turning to <FIG>, the actuator <NUM> includes a cam assembly <NUM> of any suitable design or configuration. The cam assembly <NUM> functions to actuate the shift fork <NUM> between a neutral position, an intermediate position, and a shifted position, moving the shift fork from the disengaged position <NUM> to the engaged position <NUM>.

The actuator <NUM> includes a drive system preferably comprising a motor <NUM>, a gear set <NUM>, and an output <NUM>. The motor <NUM> functions to rotate a gear set <NUM> which in-turn rotates the output <NUM>, turning the cam assembly <NUM>. The motor <NUM> may function to receive a signal from a controller to rotate clockwise or counterclockwise depending on the pivotal movement required to move the shift fork <NUM> between positions <NUM>, <NUM>. The motor <NUM> as shown in the figures is an electric motor, however, any suitable means for actuating the cam assembly <NUM> is contemplated, such as a pneumatic actuator, hydraulic actuator, a manual actuation, or the like. The motor <NUM> is configured to rotate a gear set <NUM> which rotates the cam assembly <NUM>.

As best seen in <FIG>, and <FIG>, the actuator <NUM> includes a gear set <NUM> to amplify torque generated by the motor <NUM> to increase the rotational torque of the cam <NUM>. The actuator <NUM> also includes an actuation assembly <NUM> in communication with the cam assembly <NUM>. The actuation assembly <NUM> functions to be moved by the cam assembly <NUM> to pivot and move the shift fork <NUM> between positions <NUM>, <NUM>, <NUM> (<FIG>). The actuation assembly <NUM> at least includes a shift fork <NUM>, one or more pivot couplers <NUM> connecting the shift fork <NUM> to the support <NUM>. The shift fork <NUM> may include one or more cam followers <NUM> and an actuator bracket <NUM> configured to hold and position the one or more cam followers <NUM>.

Turning to <FIG>, the shift fork <NUM> is configured to pivot between a plurality of positions and may be configured to move a dog clutch <NUM> between the plurality of positions, particularly into and out of engagement with one or more receiving gears <NUM>. The shift fork <NUM> may have a general u-shape or c-shape, comprising a top surface and two arms disposed perpendicularly from the surface, reaching towards and engaging the dog clutch <NUM>.

The cam assembly <NUM> includes a cam <NUM>. The cam <NUM> may function to actuate the cam follower <NUM>, the actuator bracket <NUM>, and the shift fork <NUM>. The cam <NUM> has a base circle <NUM> disposed around a rotational center of the cam <NUM> which rotates about a rotation axis RA and a follower portion <NUM> designed to interact with the cam follower <NUM> attached with the actuator bracket <NUM> to move the shift fork <NUM> between positions <NUM>, <NUM>, <NUM>.

The cam <NUM> may be configured to radially move relative to the rotation axis, changing the position of the cam <NUM> relative to the rotational axis (explained further below). The cam <NUM> may be designed to contact and move the cam follower <NUM> and actuator bracket <NUM> a specific distance, pivoting the shift fork <NUM> between positions <NUM>, <NUM>, <NUM>, moving the dog clutch <NUM> into or out of contact with the receiving gear <NUM>. The cam <NUM> may be connected with and rotated by the gear set <NUM>. The cam <NUM> may include one or more biasing member mounts <NUM> to receive one or more biasing members <NUM>.

The biasing members <NUM> functions to assist the actuation assembly <NUM> in rapidly moving the actuation assembly <NUM> between the disengaged position <NUM> and the engaged position <NUM>. The biasing members <NUM> may function to assist the shift fork <NUM> in overcoming a momentary blockage condition by storing potential energy in the biasing members <NUM> when compressed and releasing that energy as a force onto the cam follower <NUM> and the shift fork <NUM> (<FIG>). The one or more biasing members <NUM> may be part of the hub assembly <NUM> described further below. The biasing members <NUM> may be configured to have a length in an expanded state configured to push the shift fork <NUM> through a full stroke via the cam assembly <NUM>. The one or more biasing members <NUM> may be configured to generate substantial force to assist in the alignment and engagement of a dog clutch <NUM> with a receiving gear <NUM>. The biasing members <NUM> may be configured to have an expanded length that corresponds with the distance the shift fork must move to transition between the disengaged position <NUM> and the engaged position <NUM>. The one or more biasing members <NUM> provide a persistent application force applied through the cam <NUM> during rotation onto the cam follower <NUM>.

The cam assembly <NUM> includes a hub assembly <NUM>. The hub assembly <NUM> may function to assist the actuator system <NUM> in moving the dog clutch <NUM> into the receiving gear <NUM> when a blockage condition is present. The hub assembly <NUM> may function to move the cam <NUM> between an expanded state <NUM> and a compressed <NUM>, depending on the force exerted onto the follower portion <NUM> of the cam <NUM>. The hub assembly <NUM> may include a hub housing <NUM> that extends through an aperture <NUM> of the cam <NUM>, one or more biasing members <NUM> disposed within the cam aperture <NUM> against an interior surface <NUM> of the cam aperture <NUM> and in communication with the hub housing <NUM>, and a retainer plate <NUM>. The hub assembly <NUM> is connected with the gear set <NUM> so that the hub assembly <NUM> rotates when the motor <NUM> is actuated.

<FIG> and <FIG> illustrate the hub assembly <NUM> including the cam <NUM>. The hub housing <NUM> is connected to gear set <NUM>. The hub housing <NUM> is configured to fit within the aperture <NUM> of the cam <NUM> and is keyed to the aperture <NUM> so that when the gear set <NUM> is turned, the hub housing <NUM> causes the cam <NUM> to turn. The hub housing <NUM> abuts the cam <NUM> along contact surfaces <NUM>, <NUM>, providing an axial stop for the cam <NUM> against the hub housing <NUM>. Similarly, the retainer plate <NUM> is configured to hold the cam <NUM> and hub housing <NUM> in a desired axial relationship. As best seen in <FIG> and <FIG>, the hub housing <NUM> and an interior surface <NUM> of the aperture <NUM> are configured to receive the one or more biasing members <NUM>. In one example, such as shown in <FIG>, the biasing members <NUM> are disposed within mounts <NUM> configured as channels to accept the biasing members <NUM>. As can be seen in <FIG>, the hub housing <NUM> is disposed through the aperture <NUM> of the cam <NUM> and configured to allow the cam <NUM> to be displaced radially along the hub housing <NUM> when the rotational center of the cam <NUM> is moved radially away from the rotational axis RA, compressing the one or more biasing members <NUM> to move the shift fork <NUM> and cam assembly <NUM> from one of the plurality of intermediate positions <NUM> to an engaged position <NUM> (corresponding to the shifted position of the cam assembly <NUM>). The hub assembly <NUM> is shown in the compressed state in <FIG>, illustrating that the cam <NUM> has moved along the hub housing <NUM> compressing the biasing members <NUM>. The one or more biasing members <NUM> are compressed between the mounts <NUM>, <NUM> when a blockage condition is present as the cam <NUM> is rotated, such as seen in <FIG>.

The hub assembly <NUM> functions to assist the shift fork <NUM> transition between positions <NUM>, <NUM>, and <NUM>, moving the cam <NUM> between a neutral position corresponding to the disengaged position <NUM>, an intermediate position corresponding with the intermediate position <NUM>, and a shifted position corresponding to the engaged position <NUM>. When there is a dog clutch <NUM> misalignment causing a blockage condition, the hub assembly <NUM> applies a force F against the shift fork <NUM> compressing the one or more biasing members <NUM> between the follower portion <NUM> and the hub housing <NUM> (<FIG>). The compressed biasing members <NUM> apply a force that is great enough to quickly move the dog clutch <NUM> into position when the receiving gear <NUM> and dog clutch <NUM> are aligned.

<FIG> and <FIG> illustrate the actuation system <NUM> in a disengaged position <NUM>. The actuator <NUM> is in the disengaged position <NUM> when the shifter fork <NUM> is in the disengaged position <NUM> (corresponding to the neutral position) and the cam assembly <NUM> is in the neutral position. From the disengaged position <NUM>, the shift fork <NUM> may be moved to either side, depending on the rotational direction of the cam <NUM>.

<FIG> and <FIG> illustrate the actuator <NUM> in an intermediate position <NUM>. The intermediate position <NUM> occurs when a blockage condition, such as when there is a misalignment between the dog clutch <NUM> and the receiving gear <NUM>. During a blockage, a resistive force <NUM> is applied to the distal end of the shift fork <NUM> when the actuator is moving between the disengaged position <NUM> and the engaged position <NUM>. The blockage is caused by a momentary misalignment of the dog clutch <NUM> with the receiving gear <NUM>, so during this misalignment, the shift fork <NUM> is pressing against dog clutch <NUM> which is pressing against the receiving gear <NUM>. In some examples, such as shown in <FIG> and <FIG>, the base circle <NUM> and first section <NUM> of the cam <NUM> is free from contacting the cam followers <NUM> when the biasing members <NUM> are compressed in the intermediate position <NUM>, moving the rotational center of the cam away from the rotational axis RA. The stored energy is applied from the follower portion of the cam <NUM> onto the shift fork <NUM>. When the momentary misalignment/blockage is cleared, the stored energy released and translated into a movement force, pushing the shift fork <NUM> through the stroke into the desired position and moving the actuator <NUM> into the engaged position <NUM> and the cam assembly <NUM> into the shifted position (see <FIG>).

<FIG> and <FIG> illustrate the actuator <NUM> in an engaged position <NUM>. The actuator <NUM> is moved into the engaged position <NUM> when the cam follower <NUM> is actuated by the cam <NUM>, the cam follower <NUM> applies a pressure to the top of the shift fork <NUM> through the actuator bracket <NUM>, moving the proximal end of the shift fork <NUM> in the direction of the force which simultaneously moves the distal end of the shift fork <NUM> opposite the direction of the force relative to the pivot axis PA at the pivot coupler <NUM>. The shift fork <NUM> is moved into the engaged position <NUM>. Similarly, when the actuator <NUM> is moved from the engaged position <NUM> back to the disengaged position <NUM>, the cam <NUM> actuates the cam follower <NUM> on the opposite of the engagement position, moving the actuator bracket <NUM> and shift fork <NUM> from the engaged position <NUM> to the disengaged position in the absence of a momentary blockage condition.

Claim 1:
An actuator system comprising:
a gearbox (<NUM>) including a gear assembly (<NUM>), the gearbox (<NUM>) having an outer surface with a pair of apertures (<NUM>); and
an actuator (<NUM>) comprising:
a support (<NUM>);
a drive system connected to the support (<NUM>);
a shift fork (<NUM>) including a pair of arms, the shift fork (<NUM>) being in communication with the drive system and configured to move along a distance defining a stroke length between a disengaged position and an engaged position;
an actuation assembly (<NUM>) operatively connected with the drive system to move the shift fork (<NUM>) between a neutral position, and a shifted position, with a plurality of intermediate positions between the neutral and shifted positions;
wherein the actuator (<NUM>) is mounted onto the outer surface of the gearbox (<NUM>);
wherein the portion of the shift fork (<NUM>) within the gearbox engages the gear assembly (<NUM>) within the gearbox (<NUM>);
characterized in that the support (<NUM>) includes at least one pair of lugs (<NUM>) with each lug having an opening, and in that the pair of lugs (<NUM>) extend into the pair of apertures (<NUM>) of the gearbox (<NUM>), and at least a portion of the shift fork (<NUM>) extends through the lugs (<NUM>) and below the outer surface of the gearbox (<NUM>).