Toroidal continuously variable transmission control apparatus
First Claim
1. A toroidal continuously variable transmission control apparatus for an automotive vehicle comprising:
- a variator unit comprising;
(i) input and output disks coaxially arranged and opposing each other and having a common rotation axis;
(ii) a power roller interposed between the input and output disks to transmit torque from the input disk to the output disk via a traction oil film formed between the power roller and each of the input and output disks, using a shearing force in the traction oil film; and
(iii) a trunnion that supports a backface of the power roller so that the power roller is rotatable about a power-roller rotation axis;
the trunnion being movable in a direction of a trunnion axis perpendicular to the common rotation axis of the input and output disks and the power-roller rotation axis to cause a tilting motion of the power roller and to continuously vary a transmission ratio;
a ratio control hydraulic system comprising;
(i) a hydraulic actuator producing a displacement of the trunnion in the trunnion-axis direction from an initial position at which the power-roller rotation axis intersects the common rotation axis of the input and output disks;
(ii) a control valve hydraulically controlling operation of the hydraulic actuator;
(iii) a ratio control actuator mechanically linked to the control valve to adjust a valve position of the control valve by changing a displacement of the ratio control actuator; and
(iv) a mechanical feedback device compensating for a difference of a tilt angle of the power roller between forward and reverse operating modes and serving as a positive feedback device in the reverse operating mode and also serving as a negative feedback device in the forward operating mode during which a ratio-control-actuator displacement versus transmission ratio characteristic is relatively stable in comparison with the reverse operating mode; and
a control unit comprising;
(a) a desired transmission ratio setting section (100) setting a desired transmission ratio;
(b) a transmission ratio detection section detecting a transmission ratio;
(c) a normal-period ratio control section electronically feedback-controlling the transmission ratio based on a deviation of the transmission ratio from the desired transmission ratio so that the transmission ratio is brought closer to the desired transmission ratio, and generating a normal-period command signal to be input to the ratio control actuator for compensating for the deviation;
(d) a ratio deviation compensation enabled/disabled state determination section determining whether or not the deviation can be compensated for by the normal-period ratio control section; and
(e) an abnormal-period ratio control section generating an abnormal-period command signal to be input to the ratio control actuator to realize a ratio-control-actuator displacement capable of shifting the transmission ratio to a speed-reduction side, while keeping the trunnion out of contact with a stopper in the direction of the trunnion axis, when the ratio deviation compensation enabled/disabled state determination section determines that the deviation cannot be compensated for by the normal-period ratio control section.
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Accused Products
Abstract
In a toroidal continuously variable transmission (TCVT) control apparatus with a variator unit and a ratio control hydraulic system, an electronic TCVT control unit electronically feedback-controls a transmission ratio based on a deviation from a desired transmission ratio, and generates a normal-period command signal to be input to a step motor for compensating for the deviation. The control unit determines whether the deviation can be compensated for by electronically feedback-controlling the transmission ratio based on the deviation and generates an abnormal-period command signal to be input to the step motor to realize a step-motor displacement capable of shifting or diverging the transmission ratio to a speed-reduction side, while keeping a trunnion out of contact with a stopper in the direction of the trunnion axis, when the deviation cannot be compensated for by electronically feedback-controlling the transmission ratio based on the deviation.
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Citations
20 Claims
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1. A toroidal continuously variable transmission control apparatus for an automotive vehicle comprising:
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a variator unit comprising;
(i) input and output disks coaxially arranged and opposing each other and having a common rotation axis;
(ii) a power roller interposed between the input and output disks to transmit torque from the input disk to the output disk via a traction oil film formed between the power roller and each of the input and output disks, using a shearing force in the traction oil film; and
(iii) a trunnion that supports a backface of the power roller so that the power roller is rotatable about a power-roller rotation axis;
the trunnion being movable in a direction of a trunnion axis perpendicular to the common rotation axis of the input and output disks and the power-roller rotation axis to cause a tilting motion of the power roller and to continuously vary a transmission ratio;
a ratio control hydraulic system comprising;
(i) a hydraulic actuator producing a displacement of the trunnion in the trunnion-axis direction from an initial position at which the power-roller rotation axis intersects the common rotation axis of the input and output disks;
(ii) a control valve hydraulically controlling operation of the hydraulic actuator;
(iii) a ratio control actuator mechanically linked to the control valve to adjust a valve position of the control valve by changing a displacement of the ratio control actuator; and
(iv) a mechanical feedback device compensating for a difference of a tilt angle of the power roller between forward and reverse operating modes and serving as a positive feedback device in the reverse operating mode and also serving as a negative feedback device in the forward operating mode during which a ratio-control-actuator displacement versus transmission ratio characteristic is relatively stable in comparison with the reverse operating mode; and
a control unit comprising;
(a) a desired transmission ratio setting section (100) setting a desired transmission ratio;
(b) a transmission ratio detection section detecting a transmission ratio;
(c) a normal-period ratio control section electronically feedback-controlling the transmission ratio based on a deviation of the transmission ratio from the desired transmission ratio so that the transmission ratio is brought closer to the desired transmission ratio, and generating a normal-period command signal to be input to the ratio control actuator for compensating for the deviation;
(d) a ratio deviation compensation enabled/disabled state determination section determining whether or not the deviation can be compensated for by the normal-period ratio control section; and
(e) an abnormal-period ratio control section generating an abnormal-period command signal to be input to the ratio control actuator to realize a ratio-control-actuator displacement capable of shifting the transmission ratio to a speed-reduction side, while keeping the trunnion out of contact with a stopper in the direction of the trunnion axis, when the ratio deviation compensation enabled/disabled state determination section determines that the deviation cannot be compensated for by the normal-period ratio control section. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A toroidal continuously variable transmission control apparatus for an automotive vehicle comprising:
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a variator unit comprising;
(i) input and output disks coaxially arranged and opposing each other and having a common rotation axis;
(ii) a power roller interposed between the input and output disks to transmit torque from the input disk to the output disk via a traction oil film formed between the power roller and each of the input and output disks, using a shearing force in the traction oil film; and
(iii) a trunnion that supports a backface of the power roller so that the power roller is rotatable about a power-roller rotation axis;
the trunnion being movable in a direction of a trunnion axis perpendicular to the common rotation axis of the input and output disks and the power-roller rotation axis to cause a tilting motion of the power roller and to continuously vary a transmission ratio;
a ratio control hydraulic system comprising;
(i) a hydraulic actuator producing a displacement of the trunnion in the trunnion-axis direction from an initial position at which the power-roller rotation axis intersects the common rotation axis of the input and output disks;
(ii) a control valve hydraulically controlling operation of the hydraulic actuator;
(iii) a ratio control actuator mechanically linked to the control valve to adjust a valve position of the control valve by changing a displacement of the ratio control actuator; and
(iv) a mechanical feedback device compensating for a difference of a tilt angle of the power roller between forward and reverse operating modes and serving as a positive feedback device in the reverse operating mode and also serving as a negative feedback device in the forward operating mode during which a ratio-control-actuator displacement versus transmission ratio characteristic is relatively stable in comparison with the reverse operating mode; and
a control unit comprising;
(a) means for setting a desired transmission ratio based on a vehicle speed and an accelerator depression amount;
(b) means for detecting a transmission ratio based on an input-disk speed and an output-disk speed;
(c) means for electronically feedback-controlling the transmission ratio based on a deviation of the transmission ratio from the desired transmission ratio so that the transmission ratio is brought closer to the desired transmission ratio, and generating a normal-period command signal to be input to the ratio control actuator for compensating for the deviation;
(d) means for generating an abnormal-period command signal to be input to the ratio control actuator to realize a ratio-control-actuator displacement capable of shifting the transmission ratio to a speed-reduction side, while keeping the trunnion out of contact with a stopper in the direction of the trunnion axis; and
means for determining whether or not the deviation can be compensated for by the normal-period ratio control section, and for inputting the normal-period command signal to the ratio control actuator when the deviation can be compensated for by the normal-period ratio control section, and for inputting the abnormal-period command signal to the ratio control actuator when the deviation cannot be compensated for by the normal-period ratio control section.
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12. A method of controlling a toroidal continuously variable transmission for an automotive vehicle employing a variator unit including input and output disks coaxially arranged and opposing each other and having a common rotation axis, a power roller interposed between the input and output disks to transmit torque from the input disk to the output disk via a traction oil film formed between the power roller and each of the input and output disks, using a shearing force in the traction oil film, and a trunnion that supports a backface of the power roller so that the power roller is rotatable about a power-roller rotation axis;
- the trunnion being movable in a direction of a trunnion axis perpendicular to the common rotation axis of the input and output disks and the power-roller rotation axis to cause a tilting motion of the power roller and to continuously vary a transmission ratio, and a ratio control hydraulic system including a pressure-differential operated hydraulic servo mechanism producing a displacement of the trunnion in the trunnion-axis direction from an initial position at which the power-roller rotation axis intersects the common rotation axis of the input and output disks, a control valve creating a pressure differential for operating the hydraulic servo mechanism, a step motor mechanically linked to the control valve to adjust a valve position of the control valve by changing a displacement of the step motor, and a mechanical feedback device compensating for a difference of a tilt angle of the power roller between forward and reverse operating modes and serving as a positive feedback device in the reverse operating mode and also serving as a negative feedback device in the forward operating mode during which a ratio-control-actuator displacement versus transmission ratio characteristic is relatively stable in comparison with the reverse operating mode, the method comprising;
setting a desired transmission ratio based on a vehicle speed and an accelerator depression amount;
detecting a transmission ratio based on an input-disk speed and an output-disk speed;
electronically feedback-controlling the transmission ratio based on a deviation of the transmission ratio from the desired transmission ratio so that the transmission ratio is brought closer to the desired transmission ratio, and generating a normal-period command signal to be input to the step motor for compensating for the deviation;
determining whether or not the deviation can be compensated for by electronically feedback-controlling the transmission ratio based on the deviation; and
generating an abnormal-period command signal to be input to the step motor to realize a step-motor displacement capable of shifting the transmission ratio to a speed-reduction side, while keeping the trunnion out of contact with a stopper in the direction of the trunnion axis, when the deviation cannot be compensated for by electronically feedback-controlling the transmission ratio based on the deviation. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
- the trunnion being movable in a direction of a trunnion axis perpendicular to the common rotation axis of the input and output disks and the power-roller rotation axis to cause a tilting motion of the power roller and to continuously vary a transmission ratio, and a ratio control hydraulic system including a pressure-differential operated hydraulic servo mechanism producing a displacement of the trunnion in the trunnion-axis direction from an initial position at which the power-roller rotation axis intersects the common rotation axis of the input and output disks, a control valve creating a pressure differential for operating the hydraulic servo mechanism, a step motor mechanically linked to the control valve to adjust a valve position of the control valve by changing a displacement of the step motor, and a mechanical feedback device compensating for a difference of a tilt angle of the power roller between forward and reverse operating modes and serving as a positive feedback device in the reverse operating mode and also serving as a negative feedback device in the forward operating mode during which a ratio-control-actuator displacement versus transmission ratio characteristic is relatively stable in comparison with the reverse operating mode, the method comprising;
Specification