Abstract: A vehicle driveline control system includes monitoring when the transmission is in gear and the clutch is left open. If that condition exists for a selected amount of time, the controller provides an indication to the driver regarding the open clutch status. In one example, the controller alters the RPM rate of the engine to provide audible feedback to the driver. For example, the controller raises the engine RPM rate from an idle rate to a higher rate to simulate what the driver hears upon vehicle launch. A variety of indicators and control strategies may be used with a system designed according to this invention.

Abstract: A centrifugal clutch assembly includes movable centrifugal weight reaction surfaces that provide for actuation at varying rotational speeds. A radially movable front plate with a ramped surface changes the radial position at which the centrifugal weight begins moving the front plate axially to compress a clamp spring and begin clutch actuation. An axially movable back plate moves axially to change the magnitude of compression caused by axial movement of the front plate. The changes to clamping force corresponding to movement of the reaction surfaces of the centrifugal weight change the rotational speed required to beginning and maintain actuation of the clutch assembly.

Abstract: A centrifugal clutch assembly includes a sleeve movable to selectively engage the clutch assembly independent of rotational speed. The clutch assembly includes centrifugal weights that move radially responsive to rotation of the clutch assembly. The centrifugal weights move pressure plates between clamped and open positions in response to a desired rotational speed. The sleeve is movable to selectively engage the pressure plate independent of rotational speed of the clutch assembly.

Abstract: A control for a transmission and a clutch monitors conditions to determine when a vehicle associated with the clutch and transmission is likely in a stationary state. If the vehicle appears to be stationary, with the transmission engaged and the clutch open, then the control determines that the transmission should be moved to a neutral position. Upon movement to the neutral position, the control then closes the clutch. It is preferable for a vehicle remaining stationary to have its clutch closed and its transmission in neutral than to have its transmission engaged and its clutch open. In a further aspect of this invention, the neutral state is verified by testing the ability to move one of the transmission shift components. If the transmission shift component can move beyond a predetermined amount, this is indicative that the transmission is in neutral.

Abstract: The present invention provides a transmission including a main gear box and an auxiliary gear box secured to the main box. The auxiliary gear box includes an auxiliary shaft supporting an auxiliary gear with a clutch collar support on the auxiliary shaft adjacent to the auxiliary gear. The clutch collar is selectively actuatable between engaged and disengaged auxiliary gear positions. A piston housing is connected to the auxiliary gear box and supports solenoids fluidly connected to a piston on a shift shaft. The auxiliary box includes a bore therein supporting the shift shaft. The shift shaft is moveable axially between first and second positions in response to actuation of the solenoids corresponding to the engage and disengaged auxiliary gear positions. The shift shaft supports a shift fork that coacts with the shift collar.

Abstract: A low speed splitter transmission assembly includes a main gearbox and an auxiliary gearbox. The transmission assembly provides a relatively small numerical gear ratio step from the highest numerical gear ratio to the second highest gear ratio. The relatively small step between the highest and the second highest numerical gear ratios allows shifting from the highest numerical gear ratio during movement of the vehicle.

Abstract: A normally open clutch assembly includes a device holding a centrifugal weight in a position causing axial movement of pressure plates and thereby a clamping force between pressure plates and the friction disks. The clamping force holds the friction disks in a desired aligned position during assembly.

Abstract: The first gear/reverse gate switch of the present invention includes a detent switch including a contact pin and a contact switch. When a manual transmission is shifted to a gear not in the first gear/reverse gate, the contact pin of the detent switch engages a recessed portion on a detent mechanism such that the contact pin does not engage the contact switch. This indicates that the transmission is not in a gear in the first gear/reverse gate. When the manual transmission is shifted to a gear in the first gear/reverse gate, the interlock moves the detent, pushing the contact pin into engagement with the contact switch. This indicates that the transmission is in a gear in the first gear/reverse gate. The spring forces the detent into a “relaxed position” when not in the first gear or the reverse gate, breaking switch contact.

Abstract: The inventive transmission has at least two different shift modes for shifting between the same two gear ratios. A control unit electronically senses various vehicle conditions and based on this information selects the appropriate shift mode suited for the particular driving situation. The transmission then shifts from one gear ratio to another based on this selection.

Abstract: A strategy for overcoming a tooth butt condition includes changing a target closed clutch position over time. When a tooth butt condition exists, a controller selectively closes a clutch to provide limited engagement between the engine and the transmission. A first target closed clutch position is used on the first attempt. If the tooth butt condition is not resolved, the controller then changes the target closed clutch position to provide a different level of engagement between the engine and the transmission. This process is repeated until the tooth butt condition is resolved, a preselected period of time expires, a maximum number of attempts has been completed or the maximum desirable closed clutch position has been used.

Abstract: A detent assembly for a transmission is provided including a transmission component, such as a shift rail, movable between a plurality of shift positions including first, second, and neutral shift positions. A contoured surface on the shift rail includes first and second recesses, respectively, corresponding to the first and second shift positions. A neutral recess is arranged between the first and second shift recesses corresponding to the neutral shift position. The first and second recesses, respectively, include first and second transition surfaces sloping towards the neutral recess with the second transition surface being steeper than the first transition surface. A detent assembly includes a biasing member and a detent member with the biasing member urging the detent member into engagement with the contoured surface. The biasing member generates a first work along the first transition surface and a second force along the second transition surface greater than the first work.

Abstract: A transmission gear position sensing assembly includes a transmission housing with a bore having a shift shaft disposed therein. The shift shaft has an axis about which the shaft translates as the transmission is shifted between gear positions. The housing includes a hole with a switch assembly received in the hole transverse to the shift shaft axis. The shift shaft includes a profile aligned with the switch assembly. The profile has first, second, and third surfaces respectively spaced radially from the axis a first, second and third distance. The third surface is arranged between the first and second surfaces. The third distance is larger than the first and the second distances, and the third surface corresponds to a neutral gear position. The switch assembly includes a member biased to engagement with the profile by a spring. The switch assembly senses the gear precision by the corresponding location along the profile.

Abstract: A system and method of controlling an automatic clutch to prevent a motor vehicle engine from stalling is disclosed. The method includes the steps of determining an engine stall threshold, detecting accelerator pedal actuation, detecting current engine speed, and comparing current engine speed to the engine stall threshold. If the engine speed is below the engine stall threshold, a controller detects and compares vehicle acceleration to predetermined threshold acceleration such that the automatic clutch is actuated only when the vehicle acceleration is below the threshold acceleration. The system includes the step of detecting foot brake position such that the automatic clutch is only actuated if the foot brake is properly actuated. The controller will then actuate the automatic clutch to proportionally decouple the engine from the transmission to prevent engine stall. The automatic clutch will remain open until detecting a predetermined clearing condition.

Abstract: A plurality of pins couple the cones and the shift collar of a transmission auxiliary section together so that they rotate as a group. When the shift collar is moved laterally from neutral, the shift collar engages blocking surfaces on the pins and moves the corresponding cone to match the speeds of the input shaft and the corresponding gear. The invention shortens the pin lengths of the synchronizer and therefore the length of the transmission, by eliminating contact between the shift collar and the small diameters of the pins in the neutral position.

Abstract: Engine braking in a vehicle driveline during transmission upshifts is controlled to provide more efficient and accurate speed synchronization. The physical limitations on the engine brake components are taken into account to determine a delay between an off request and the actual time that the engine brake turns off. This delay is factored into the time when the engine brake off request is made prior to a predicted time when the actual engine speed will meet a desired engine speed. By accounting for such delay, overshoot and undershoot during speed synchronization is avoided.

Abstract: A torsional vibration damper is used for reducing or eliminating torsional vibrations in a vehicle driveline. A hub portion includes an elongated body with a first axial dimension. A disk portion is supported by the hub portion and has a second axial dimension that is smaller than the first axial dimension of the hub portion. The hub portion preferably is secured to rotate with an engine flywheel and the disk portion preferably is adapted to rotate with a transmission input shaft. The disk portion preferably supports a plurality of damping members, which can be positioned at different radial or axial locations depending on the needs of a particular situation.

Abstract: The detent and neutral switch mechanism includes a roller detent pin attached to a roller spring. The detent pin engages contoured shift fork extensions and resists movement of the shift fork extensions when gears are shifted and creates a “shift feel.” A neutral switch positioned above the roller spring indicates when the transmission is in neutral. When the transmission is in neutral, the deep neutral detent notches on the shift fork extensions are aligned, lowering the detent pin and disengaging the roller spring from the position switch, indicating the transmission is in neutral and that it is safe to make a shift. When the transmission is in gear or in the process of making a shift, the detent pin engages raised in-gear notches or detent peaks, respectively, engaging the roller spring with the position switch indicating that the transmission is not in neutral.

Abstract: A manually controlled transmission includes a combined detent and interlock pin mechanism. The elongated interlock pin prevents surrounding shift fork extensions from being engaged when a desired shift fork extension is selected. A recess in the interlock pin allows engagement of a shift lever with a desired shift fork extension, and opposing sides of the interlock pin engage shift finger notches in the other shift fork extensions to prevent their movement. Detent springs attached to the manually controlled transmission substantially contact opposing ends of the sliding interlock pin to provide resistance as an end of the interlock pin substantially contacts the detent spring. An anti-rotate pin positioned proximate to the interlock pin prevents rotation, but not translation, of interlock pin.

Abstract: An improved clutch has a distinct force ratio for holding than it does for release. A distinct ratio is achieved by having an abutment surface between a retainer and a diaphragm spring be positioned radially outward from a contact location between a release sleeve and the diaphragm spring for releasing the clutch. The retainer is separately axially movable relative to the release sleeve, and surrounds the release sleeve. In this way, the holding force is applied at a lever distance from an axial center line of the clutch which is greater than the distance to the point of contact for release of the diaphragm spring. This provides both a higher holding force and yet a lower release force.

Abstract: An auxiliary box for a heavy vehicle transmission includes a shift cylinder wherein fluid drives a piston in a first direction, and a spring drives a shift fork in an opposed second direction. If fluid is supplied to drive the piston in the first direction, a first gear is engaged in the auxiliary box, and if fluid is relieved the spring drives a shift fork to engage a second piston. The invention thus eliminates some of the fluid controls and components in the prior art.