DEVICE FOR DUAL OPERATING FUNCTION UNDER A CONDITION OF LOSS OF SYSTEM POWER
Cross Reference to Related Requests This application claims the benefit of the provisional North American application no. 60 / 796,473, filed May 1, 2006, which is incorporated by reference. Field of the Invention The present invention relates generally to a clutch actuator and more particularly to a clutch actuator that includes a clamping device that serves to lock the clutch actuator to hold the clutch in an open position, or to allow the actuator of clutch move the clutch to a closed position. Background of the Invention In a vehicle having an electrically operated clutch, it is desirable to be able to provide a fail-safe mode of operation for the clutch in the case of a power loss, such as a loss of system power to supply the clutch. power to the clutch actuator. In the case of a loss of power loss when the vehicle is stopped with the clutch disengaged or open and with the engine running, it is desirable to ensure that a loss of power does not cause the clutch actuator to engage or close the clutch which can result in the vehicle jumping
towards the front. Alternatively, if a loss of power occurs when the vehicle is moving and the electrically operated clutch has been uncoupled, such as halfway through a shift of the gear, it is desirable for the clutch to move to an engaged position. For example, when a vehicle is traveling downhill it is desirable to provide clutch engagement during a power loss condition to connect the drive wheels to the engine so that the engine is braked to facilitate the reduction of vehicle speed. In that situation, the clutch must be capable of being driven to move from an uncoupled position to a coupled position. Accordingly it can be seen that two opposite conditions of the clutch are required for a power loss condition of the vehicle system. BRIEF DESCRIPTION OF THE INVENTION According to another aspect of the invention, an actuator for a clutch, the actuator has a motor and a drive train that receives the rotational input of the motor, wherein the movement of the drive train drives a clutch between Coupled and uncoupled positions. The actuator also includes a clamping device for holding the drive train of the actuator stationary to a predetermined position in a first power loss condition and for releasing the drive train of the actuator for movement in a second condition
of loss of power. The motor is driven by a rotational output of the drive train in the second power loss condition. According to other aspects of the invention, an apparatus is provided in a vehicle having a power train including a clutch located between a motor and the driven wheels, the apparatus includes an actuator for the clutch, the actuator has a motor and a source of power to energize the engine. A driving train of an actuator receives a rotational input of the motor, when the movement of the drive train drives the clutch between coupling and uncoupling positions. A holding device holds the drive train stationary at a predetermined position in a first power loss condition that exhibits a power loss from the power source when the vehicle is stationary and the clutch is uncoupled, and to release the drive train for movement in a second power loss condition consisting of the loss of power consisting of the loss of power from the power source when the vehicle is moving and the clutch is uncoupled. The motor is driven by a rotational output of the drive train in the second power loss condition. According to another aspect of the invention, an actuator is provided for a clutch consisting of a housing, a motor that includes a stator and a rotor, a shaft attached to the rotor of the
motor and a bra device. The fastener device has a body including an electromagnet, wherein the shaft rotates through the body. A rotor of the fastener device is locked to the shaft to perform a rotational movement with the shaft and the rotor of the fastener device is held to perform longitudinal movement relative to the shaft. An armature is located between the body and the rotor of the fastener device where the shaft passes through the armature. A spring is located between the body and the armature to push the armature away from the body to cause the rotor clamping device to engage the housing to prevent the rotation movement of the shaft. A controller is provided to control the electric power supplied by the power source to the motor. The controller includes means for responding to at least one of the first and second power loss conditions, wherein the controller maintains a control mode to drive the motor in response to the first power loss condition and the controller refers to Another control mode for generating electricity from the engine in response to the second power loss condition. BRIEF DESCRIPTION OF THE DRAWINGS Although the specification concludes with the claims that particularly describe and claim the present invention, it is believed that the present invention will be better understood from the following description in conjunction with the drawings of the figures,
in which like reference numbers identify similar elements, and wherein: Figure 1 is a system diagram including an electric clutch actuator of the present invention; Figure 2 is a cross-sectional view of the components of the electric clutch actuator contained within an ECA housing; Figure 3 is a cross-sectional view of a clutch that can be controlled with the electric clutch actuator; Figure 4 is a schematic portion of a circuit for controlling a motor in the electric clutch actuator; Figure 5 is a graph of an average breakout torque and a peak phase current of the engine and various engine speeds; Y
Figure 6 is a diagram for controlling the switching of the useful cycle performed by the circuit of Figure 4 based on the measured bus voltage. Detailed Description of the Invention In the following detailed description of the preferred embodiment, reference is made to the accompanying drawings that are a part thereof, and in which a specific preferred embodiment is shown by way of illustration, and not in the form of limitation. in which the invention can be put into practice. It is understood that other modalities and changes can be used that can be made without departing from the spirit and scope of the present invention. Referring now to Figure 1 a clutch actuator
electrical (ECA) 10 constructed in accordance with the principles of the present invention. The EVA 10 is shown diagrammatically incorporated in a vehicle. The ECA 10 has an electronic controller 12 including controls 14, software 16 connected to the controls 14, and electronic power circuit 18, for example field effect transistors (FET), controlled by the software 16. The ECA 10 is connected to the power circuit for the vehicle including a vehicle battery 2 and vehicle ignition 22. Vehicle power train signals including signals from a transmission ECU 24, a motor speed sensor 26 and other sensors 28 the ACE 10 is fed as input signals which are processed by means of the ECA 10 to control the outputs of the controller 12. The outputs of the controller 12 including include voltage outputs to energize a stator 30 of a DC magnetless brushless motor. 32, a fastening device 34 for operating a motor rotor 36 of the motor 32, and a sensor circuit board 38 for receiving signals indicating the operating state of the motor 32. The ECA 10 also includes a planetary gear train40 that receive an output the motor rotor 36. The planetary gear train 40 having a gear reducer that produces an output to control the actuation of the clutch actuator 98. Referring to Figure 2, the components described above
of the ECA 10 are contained within an ECA housing 44. The motor 32 includes an outer stationary portion that has a stack of stators 46 that carries coils of wire 48 to define the stator 30. The rotor of the motor 36 is located within the stator 30. and presents sectors of permanent magnets driven by means of a magnetic field of the stator 30 created by means of the current supplied under the control of the controller 12 to produce rotation of the motor rotor 36 in a known manner. It should be understood that although the present invention is described incorporating a brushless permanent magnet motor 32, the principles described herein may also be implemented using a permanent magnet motor with brush. The motor rotor 36 is rigidly mounted on a rotor shaft 50 to provide a rotary output of the motor 32. The rotor shaft 50 extends through the fastener device 34 including a brake housing 68 enclosing a fastener device rotor. 56, an armature plate 60 and a coil assembly 74. A slot member 52 is fixedly attached to the motor shaft 50 having an outer surface defining a plurality of slots 54. The rotor of the fastening device 56 is held in the member of slot 52 and includes an inner surface defining a plurality of slots 58 coupled with slots 54 of slot member 52. The clamping device rotor 56 can move axially along slit member 52 and is coupled with slit member 52. slot 52 to rotate with the tree
rotor 50. The armature plate 60 is positioned near the rotor of the fastening device 56 and includes an opening 62 positioned around and outside the coupling of the slot member 52. The coil assembly 74 comprises a body portion 76 mounted in the housing of the housing. brake 68 and is maintained in a stationary relationship with respect to brake housing 68 and ECA housing 44. Body portion 76 includes a first annular region 78 that contains an electromagnet that has a coil 80, and a second annular region 82 that contains a compression spring 84. One end of the spring 84 is engaged against the inner surface of the second annular region 82 and an opposite end of the spring 84 is engaged against the armor lacquer 60 for pushing the armature plate 60 and a rotor of the device. fastener 56 away from the coil assembly 74. The armature plate 60 includes a mating surface 70 for coupling a first contact surface 71 of the rotor of the clamping device 56, and the rotor of the clamping device 56 further includes a second contact surface 72 for coupling a braking surface 73 of the braking housing 68. During a deactivated state of the clamping device 34, the rotor of the clamping device 56 is urged by the armature plate 60 to cause the second contact surface 72 to frictionally engage the braking surface 73 and to brake or resist the rotor of the clamping device 56 and the broken shaft 50 to rotate. The body portion 76 is preferably formed of a
magnetic material, such as steel material and is insulated from the coil 80. Similarly, the armor plate 60 has a magnetic material. The coil 80 is connected to the electric power 18 to conduct a current through the coil 80 to create an electromagnetic field in the body portion 76 in an activated state of the fastening device 34. During the activated state of the fastening device 34, the armor plate 60 is drawn against the force of spring 84 towards body portion 76, releasing the rotor of the fastening device 56 from the frictional coupling with the brake housing 68 and releasing the rotor shaft 50 for rotational movement relative to the housing of the brake 68. A planetary gear 86 is fixedly attached to one end of the rotor shaft 50. away from the motor 32, and a portion of the rotor shaft 50 adjacent to the planetary gear 86 passes through and is supported by in-bearing 88 mounted in the body portion 76. The sun gear 86 is part of the planetary gear train 40 and provides a input rotation movement to a plurality of planetary gears in a group of planetary gears 90 connected to a series of additional planetary gear groups 92, 94. The planetary gear train 40 provides a gear reduction of the rotor shaft to a shaft output ECA 96, such that the output speed of output shaft 96 is substantially lower than the input speed of the rotary shaft 50 with an increase in the output torque on the output shaft 96.
Referring to Figure 3, the output shaft 96 is connected as an inlet to the clutch actuator 98 for a clutch 100. The illustrated clutch 100 has a clutch housing 102 connected to a crank shaft 103 of a motor (not shown) to urge the clutch housing 102 in a rotational movement. An intermediate plate 104 and a pressure plate 106 are supported for rotation with the clutch housing 102. The clutch housing 102 includes a mating surface 108, the intermediate plate 104 includes a pair of mating surfaces 110, 112 and the pressure plate 106 includes a coupling surface 114. A first driven plate 116 is located between the coupling surfaces 108, 110, and a second driven plate 118 is located between the coupling surfaces 112, 114. The first and second driven plates. second 116, 118 each include a respective slotted passage 120, 122 for coupling a slot portion 124 of an input shaft 126. A release sleeve 128 is held for axial movement to the input shaft 126 and engages the ends distal of the release levers 130 mounted for pivotal movement in the clutch housing 120. The release sleeve 128 is pushed a to a coupling position by means of one or more pressure springs 132, causing the release of the levers 130 to press against the pressure plate 106, so that the driven plates 116, 118
trap between respective mating surfaces 108, 110, and 112, 114 to cause the input shaft 126 to rotate with rotation of the clutch housing 102 It should be noted that the clutch 100 is described for illustrative purposes only and the present invention is not limited for use with this particular clutch. The clutch actuator 98 includes an actuator arm 134 that is rotated with the rotation of the output shaft 96. An end 136 of the actuator arm 134 is positioned to engage an outer housing surface 138 of the release bearing 140. which is coupled with the release arm 128 When the output shaft 96 is rotated counterclockwise as shown in Figure 3, the end 136 of the actuator arm engages with the surface of the housing 138 for pushing the release sleeve 128 away from the clutch housing 102, such that the coupling surfaces 108, 110 and 112, 114 are uncoupled from the driven plates 11, 118 to disengage the clutch 100 The rotation of the output shaft 96 in the opposite direction, that is in the clockwise direction this will result in clutch engagement 100 In order that the clutch 100 is disengaged or engaged, the support device 34 must be activated to allow the output shaft 96 to rotate and move the clutch actuator 98 in the case of a power loss of the system and in the absence of a supplementary power source for the fastener device 34, the
output shaft 96 will lock in its current position at the time of power loss. This would typically be desirable in a first power loss condition if the vehicle is stationary with the clutch 100 decoupled, in order to prevent the vehicle from springing forward as a result of the clutch suddenly being buckled during a power loss of the system. . On the other hand, in a second power loss condition, if the vehicle moves during a power loss of the system with clutch 100 decoupled, it would typically be desirable to allow the clutch 100 to engage to use engine braking to stop the vehicle, particularly if the vehicle is traveling downhill. As described below, the present invention provides a control for the fastener device 34 and the motor 32 that resolves those two power loss conditions of the system. Referring to figure 4, an inverter circuit 142 is illustrated to control the current to the motor 32, which is illustrated as a brushless three-phase permanent magnet motor that can be controlled using a pulse width modulation (PWM) control. The circuit 142 includes three high-side FETs Q1, Q3, Q5 and three low-side FETs Q2, Q4, Q6 which are controlled by the software to carry out the control of the motor 32. In the first power loss condition of the system, where it is desired to maintain the current position of the clutch 100, such as when the vehicle is stationary, the controller 12 operates in a mode in which three FETs
Low side Q2, Q4, Q6 are set in a 100% duty cycle to short-circuit the motor terminals. If the rotor of the motor 36 is rotating an electromotive recoil force will be created through the impedance of the motor (this is the vector sum of the resistance and the synchronous reactance) as a result of the terminals in short, the resulting circulating current in the Motor coils 48 will generate a reverse reaction torque to reduce the electromotive force of recoil. In other words a brake torque will be generated to reduce the movement of the motor. Referring to FIG. 5, an example of the average brake torque and the peak phase current of the motor 32 at various motor speeds is illustrated. The peak current is almost saturated at high speed due to the synchronous reactance, that is the angular motor of the motor x the inductance of the motor, of the motor 32. The synchronous reactance dominates a resistance of the motor at high speed, so that the current It saturates at high speed. Accordingly, the effect of the reactance allows the short circuit of the three motor terminals even at high motor speeds. The support device 34 will be deactivated during the first power loss condition where it is desired to maintain the current position of the clutch, and a circuit (not shown) can be provided to quickly collapse the magnetic field generated by the coil assembly 74 of the device. 34. If the rotor of the motor 36 is still rotating, the torque of the motor braking will reduce the rotor of the motor 36 to a speed at which the
The rotor of the clamping device 56 will brake the rotation of the rotor of the rotor 36 and hold the rotor shaft 50 against the rear rotation This is the rotor of the clamping device 56 will retain the rotor shaft 50 fixed in position to maintain the output shaft 96 and the actuator 98 in a decoupling position, operating against the pressure spring 132 to maintain the release sleeve 128, and thus the clutch 100, in the decoupling position In the second power loss condition of the system in which it is desired to move the clutch 100 from the uncoupled to the coupled position, such that when the vehicle moves, the controller 12 operates in a mode in which the three low side FETs Q2, Q4, Q6 will be operated to short-circuit the motor terminals between Yes during a predetermined braking portion (DB) of the useful cycle, and all the FETs will be off during the remaining regenerative portion (DR) of the useful cycle, ie during a portion of the duty cycle equal to 1-DB As will be described in more detail below, during the second power loss condition, the activation of the device 34 to release the rotor shaft 50 during rotation for a period is taken into account of sufficient time to allow the clutch 100 to engage. During the rotation period of the rotor shaft 50, the brake torque will be applied from the engine 32 during the braking portion of the useful cycle DB, in a manner similar to that described for the first power loss condition, and the regenerative energy will be provided from the motor 32 during the regenerative portion
remaining DR of the useful cycle. The ECA controller bus includes a controller bus capacitor 144, see Figure 2, to maintain a stored amount of energy during the normal operation of the ECA controller 12, and to receive and store the regenerative energy from the engine 32 during the regenerative portion DR of the useful cycle. The energy stored in the capacitor 144 is used to supply the power to the ECA controller 12 and the clamping device 34 during a power loss condition of the system. The capacitor 144 is capable of storing sufficient energy, including the additional regenerative energy received from the motor 32, to maintain the clamping device 34 in the rotational state of the output shaft 96 and the clutch actuator 90 for the coupling position for the clutch engagement 100. This is during the rotation of the output shaft 96 and the rotor shaft 50, as the clutch 100 moves to the engagement position under the force of the spring (s) 132, the motor rotor 36 will rotate to produce the regenerative energy supplied to the capacitor during the regenerative portion DR of the useful cycle. The regenerative energy will continue to contribute to any energy already stored in the capacitor 144 to maintain the fastener device 34 in the activated state, allowing continuous rotation of the output shaft 96 and the clutch actuator 98 until the clutch 100 is fully engaged at the end. of the trip of the release sleeve 128 under the influence of the energy stored in the or
springs 132. The bus voltage Vbus may increase or decrease in the balance between the regenerative energy supplied and the amount of power required to activate the clamping device 34 and operate the CA 12 controller. Referring to Fig. 6, a state diagram is shown. to control the useful cycle based on the measured bus voltage Vbus. In particular, the brake portion D of the useful cycle is initially set to 0.95 (DR = 0.05) at the start of the second power loss condition. If Vbus is greater than 20 V, then DB rises to 0.97 with the corresponding reduction in the regenerative portion DR of the useful cycle to 0.03. If the Vbus falls below 18V when DB is set to 0.97, then DB will again be set to 0.95. If Vbus is greater than 30 V when DB is set to 0.97, then DB rises to 0.99 with a corresponding reduction in the regenerative portion DR of the useful cycle to 0.01. If Vbus drops below 28V, when DB is set to 0.99, then DB is set again to 0.97. It can be seen that ECA 10 is able to meet two power loss conditions described above. For the loss condition d power in which the housing 100 is uncoupled during a power loss of the system and the desired action the clutch 100 is to remain in its current position state, the fastening device 134 will move to its deactivated position for preventing the movement of an actuator 98 for the clutch 100. For the power loss condition in which the clutch 100 is decoupled during a loss of power of the
system and the desired action is for the clutch 100 to move to a coupled position state, the ECA engine 32 is used as a generator to convert the power power of the springs of the clutch pressure 132 into electrical energy to provide power to energize the fastener device 134 to keep it active Holding the fastener device 134 enabled allows the clutch 100 to move to the engaged position and allow braking with the vehicle's engine to be used during a power loss of the system Although they have been illustrated and described particular embodiments of the present invention, it will be obvious to those described in the art that various other changes and modifications may be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all the changes and modifications they are within the scope of the invention