Toroidal continuously variable transmission
First Claim
1. A toroidal continuously variable transmission comprising:
- an input disk to which rotation of a prime mover is transmitted;
an output disk coaxially arranged with and opposed to the input disk, the output disk adapted to have a driving connection with and to have a driven connection with a road wheel;
a power roller interposed between the input and output disks under axial preload for power transmission;
a trunnion rotatably supporting the power roller to permit a tilting motion of the power roller about a trunnion axis perpendicular to a rotation axis of the power roller for ratio changing;
a primary oil pump driven by the prime mover to produce a hydraulic pressure;
a secondary oil pump driven in response to rotation of the road wheel to produce a hydraulic pressure;
a hydraulic servo mechanism connected to the trunnion to move the trunnion in a direction of the trunnion axis so as to cause the tilting motion of the power roller by creating an offset of the power roller from a neutral position in the direction of the trunnion axis, the neutral position being a non-ratio-changing position at which the rotation axis of the power roller intersects a rotation axis of the input and output disks;
a feedback device through which a degree of progress for ratio changing is fed back to the hydraulic servo mechanism so that the power roller returns to the neutral position when a desired transmission ratio has been reached;
the hydraulic servo mechanism hydraulically operated by at least one of the hydraulic pressure from the primary oil pump and the hydraulic pressure from the secondary oil pump; and
a hydraulic circuit that supplies the hydraulic pressure from the secondary oil pump to the hydraulic servo mechanism when the road wheel is rotated in a stopped state of the prime mover, so that an actual transmission ratio is brought closer to the desired transmission ratio.
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Accused Products
Abstract
In a toroidal continuously variable transmission, a secondary oil pump is provided in addition to a primary oil pump driven by an engine. The secondary oil pump is driven in response to rotation of a road wheel. A hydraulic servo mechanism is connected to a trunnion to create an offset of the power roller from a neutral position for a tilting motion of the power roller. A feedback device is provided for feeding a degree of progress for ratio changing back to the hydraulic servo mechanism so that the power roller returns to the neutral position when a desired transmission ratio has been reached. When the road wheel is rotated in a stopped state of the engine, hydraulic pressure from the secondary oil pump is supplied to the hydraulic servo mechanism so that an actual transmission ratio is brought closer to a desired transmission ratio.
96 Citations
18 Claims
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1. A toroidal continuously variable transmission comprising:
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an input disk to which rotation of a prime mover is transmitted;
an output disk coaxially arranged with and opposed to the input disk, the output disk adapted to have a driving connection with and to have a driven connection with a road wheel;
a power roller interposed between the input and output disks under axial preload for power transmission;
a trunnion rotatably supporting the power roller to permit a tilting motion of the power roller about a trunnion axis perpendicular to a rotation axis of the power roller for ratio changing;
a primary oil pump driven by the prime mover to produce a hydraulic pressure;
a secondary oil pump driven in response to rotation of the road wheel to produce a hydraulic pressure;
a hydraulic servo mechanism connected to the trunnion to move the trunnion in a direction of the trunnion axis so as to cause the tilting motion of the power roller by creating an offset of the power roller from a neutral position in the direction of the trunnion axis, the neutral position being a non-ratio-changing position at which the rotation axis of the power roller intersects a rotation axis of the input and output disks;
a feedback device through which a degree of progress for ratio changing is fed back to the hydraulic servo mechanism so that the power roller returns to the neutral position when a desired transmission ratio has been reached;
the hydraulic servo mechanism hydraulically operated by at least one of the hydraulic pressure from the primary oil pump and the hydraulic pressure from the secondary oil pump; and
a hydraulic circuit that supplies the hydraulic pressure from the secondary oil pump to the hydraulic servo mechanism when the road wheel is rotated in a stopped state of the prime mover, so that an actual transmission ratio is brought closer to the desired transmission ratio. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 15, 16, 17, 18)
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14. A toroidal continuously variable transmission comprising:
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an input disk to which rotation of a prime mover is transmitted;
an output disk coaxially arranged with and opposed to the input disk, the output disk adapted to have a driving connection with and to have a driven connection with a road wheel;
a power roller interposed between the input and output disks under axial preload for power transmission;
a trunnion rotatably supporting the power roller to permit a tilting motion of the power roller about a trunnion axis perpendicular to a rotation axis of the power roller for ratio changing;
primary oil pump means driven by the prime mover for producing a hydraulic pressure;
secondary oil pump means driven in response to rotation of the road wheel for producing a hydraulic pressure;
hydraulic servo means connected to the trunnion for moving the trunnion in a direction of the trunnion axis so as to cause the tilting motion of the power roller by creating an offset of the power roller from a neutral position in the direction of the trunnion axis, the neutral position being a non-ratio-changing position at which the rotation axis of the power roller intersects a rotation axis of the input and output disks;
feedback means for mechanically feeding a degree of progress for ratio changing back to the hydraulic servo means so that the power roller returns to the neutral position when a desired transmission ratio has been reached;
the hydraulic servo means hydraulically operated by at least one of the hydraulic pressure from the primary oil pump means and the hydraulic pressure from the secondary oil pump means; and
a hydraulic circuit that supplies the hydraulic pressure from the secondary oil pump means to the hydraulic servo means when the road wheel is rotated in a stopped state of the prime mover, so that an actual transmission ratio is brought closer to the desired transmission ratio.
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Specification