The present invention relates generally to clutches for transmissions and, more specifically, to an electronic clutch actuator for actuation of a clutch in a transmission.
Conventional vehicles typically include an engine having a rotational output that provides a rotational input into a transmission such as a manual transmission for a powertrain system of the vehicle. The transmission changes a rotational speed and torque generated by the output of the engine through a series of predetermined gearsets in a gearbox to transmit power to one or more wheels of the vehicle, whereby changing between the gearsets enables the vehicle to travel at different vehicle speeds for a given engine speed.
When a vehicle operator or driver wants to change from one gear to another, the driver presses down on a clutch footpedal of the vehicle. This operates a single clutch via a linkage, which disconnects the output of the engine from the input into the gearbox and interrupts power flow to the transmission. Then the vehicle operator uses a shift lever to select a new gear, a process that typically involves moving a toothed collar from one gear to another gear of a different size. In the gearbox, synchronizers match the gears before they are engaged to prevent grinding. Once the new gear is engaged, the driver releases the clutch footpedal, which re-connects the output of the engine to the input of the gearbox to transmit power to the wheels.
For the above-described transmission, original equipment manufacturers are developing enhanced clutch systems for manual transmissions to continually reduce carbon dioxide output and meet fuel saving requirements, which can provide new cost effective functionalities like automated free rolling operation (sailing) when the driver does not require engine torque. For example, an enhanced clutch system includes an electronic clutch actuator driven from vehicle controls to engage and disengage the clutch. However, the enhanced clutch system must function conventionally, and controls the clutch independently of the driver's actions as well for shifting gears in transmissions. Thus, there is a need in the art to provide an electronic clutch actuator for actuation of a clutch in a transmission.
The present invention provides an electronic clutch actuator for actuation of a clutch in a transmission of a vehicle including a clutch master cylinder having a fluid cavity therein and adapted to be in fluid communication with a clutch slave cylinder coupled to the clutch of the transmission, a movable piston disposed in the fluid cavity of the clutch master cylinder, a rotatable screw having one end coupled to the piston to translate the piston, a geartrain disposed perpendicular to the rotatable screw to rotate the rotatable screw, and a motor having an output shaft disposed perpendicular to the geartrain to form a U-shaped arrangement to rotate gears of the geartrain.
One advantage of the present invention is that an electronic clutch actuator is provided for actuation of a clutch in a transmission having a U-shaped arrangement. Another advantage of the present invention is that the electronic clutch actuator uses a U-shape arrangement of system components along with a motor sensor and piston sensor on one board. Yet another advantage of the present invention is that the electronic clutch actuator driven from vehicle controls. Still another advantage of the present invention is that the electronic clutch actuator implements a separate component adapted to manual transmissions. A further advantage of the present invention is that the electronic clutch actuator is an “add-on” to the clutch system without any change in a vehicle driver's actions.
Other objects, features, and advantages of the present invention will be readily appreciated as the same becomes better understood after reading the subsequent description taken in connection with the accompanying drawings.
Referring now to the figures, where like numerals are used to designate like structure unless otherwise indicated, a system 10, according to the present invention, for actuation of a clutch, generally indicated at 12, in
As illustrated in
The system 10 also includes an electronic clutch actuator, according to the present invention and generally indicated at 18, for actuating the clutch 12. In one embodiment, the electronic clutch actuator 18 includes a clutch master cylinder 20 fluidly connected by a conduit 22 to the clutch slave cylinder 16. The electronic clutch actuator 18 also includes a movable piston 24 disposed in the clutch master cylinder 20. It should be appreciated that movement of the piston 24 causes movement of fluid to actuate the clutch slave cylinder 16.
The electronic clutch actuator 18 includes a rotatable screw 26 coupled to the piston 24 to move or translate the piston 24. The rotatable screw 26 may cooperate with the piston 24 such that, when the rotatable screw 26 is rotated, this rotational movement causes translational movement of the piston 24. The electronic clutch actuator 18 includes a motor 28 for rotating the rotatable screw 26. The motor 28 is of a brushless direct current (BLDC) reversible or two directional output type and connected to a source of power. The electronic clutch actuator 18 further includes a geartrain, generally indicated at 30, between the motor 28 and the rotatable screw 26. In one embodiment, the geartrain 30 includes a first gear 32 coupled to the rotatable screw 26 and a second gear 34 coupled to the motor 28 for a predetermined gear ratio. It should be appreciated that the first gear 32 and second gear 34 meshingly engage each other to reduce the rotational output of the motor 28 to the rotatable screw 26.
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The electronic clutch actuator 18 also includes a gear housing 76 disposed perpendicular to the clutch master cylinder 20 to form a general “L” shape. The gear housing 76 may be a separate housing or integral with the clutch master cylinder 20. The gear housing 76 includes a cavity 78 to house the geartrain 30. The geartrain 30 includes a rotatable shaft 80 extending axially through the rotatable screw 26 and into the passageway 53 of the piston 24 and through the cavity 78 of the gear housing 76. The shaft 80 is rotatably supported in the gear housing 76 by a bearing 82. The bearing 82 may be of a roller ball type with races formed by the gear housing 76. The first gear 32 is disposed in the cavity 78 and about the shaft 80. It should be appreciated that a bushing 84 may be disposed in the gear housing 76 to support the end of the shaft 80.
The gear housing 76 also includes an outer recess 86 to receive an axially extending portion 88 of the motor 28. The gear housing 76 includes an aperture 90 extending axially from the recess 86 and communicating with the cavity 78 to receive an output shaft 92 of the motor 28. The output shaft 92 may be rotatably supported in the gear housing 76 by a bearing 82 or a torsion spring brake 94 to prevent back driving of the output shaft 92 of the motor 28. The second gear 34 is disposed in the cavity 78 and about the output shaft 92. It should be appreciated that a bushing 96 may be disposed in the gear housing 76 to support the end of the output shaft 92. It should also be appreciated that the torsion spring brake 94 is optional. It should further be appreciated that the piston 24, geartrain 30, and motor 28 form a general “U” shape arrangement.
The electronic clutch actuator 18 includes an electronic control unit 98 disposed adjacent the motor 28 and the piston 24. The electronic control unit 98 includes a circuit board 100 disposed at a back or rear end of the motor 28 opposite the output shaft 92. The circuit board 100 is generally planar and orientated perpendicular to the piston 24. The electronic control unit 100 includes a piston sensor 102 disposed at one end of the circuit board 100 to sense the linear position of the magnet 75 on the piston 24. The electronic control unit 100 further includes a motor sensor 104 spaced radially from the piston sensor 102 to sense the rotational position of the output shaft 92 of the motor 28. The piston sensor 102 and the motor sensor 104 are of a Hall-effect or variable reluctance type. It should be appreciated that the motor sensor 104 and the piston sensor 102 are arranged on one electronic control unit 98. It should also be appreciated that the electronic control unit 98 and ECM 40 may be separate or one in the same. It should further be appreciated that the electronic clutch actuator 18 is for automated manual clutch transmissions.
Accordingly, the system 10 of the present invention is provided as an enhanced clutch system for actuation of the clutch 12 having the electronic clutch actuator 18 for a transmission of a vehicle. The system 10 of the present invention allows both a vehicle driver and the system 10 to control the clutch 12 seamlessly for shifting. The system 10 of the present invention is an “add-on” to the clutch 12 without any change in a vehicle driver's actions.
The present invention has been described in an illustrative manner. It is to be understood that the terminology which has been used is intended to be in the nature of words of description rather than of limitation.
Many modifications and variations of the present invention are possible in light of the above teachings. Therefore, within the scope of the appended claims, the invention may be practiced other than as specifically described.
The present application claims priority to and all the benefits of U.S. Provisional Patent Application No. 62/434,815, filed on Dec. 15, 2016, which is hereby expressly incorporated herein by reference in its entirety.
Number | Date | Country | |
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62434815 | Dec 2016 | US |