Assemblies and methods for clamping force generation
View Patent ↗Mechanisms and methods for clamping force generation are disclosed. In one embodiment, a clamping force generator system includes a permanent magnet bearing coupled to a traction ring and to a torque coupling. The traction ring can be provided with an electromagnetic bearing rotor and the torque coupling can be provided with an electromagnetic bearing stator. In some embodiments, a mechanical load cam, a permanent magnet bearing, and an electromagnetic bearing cooperate to generate a clamping force between the traction rings, the power rollers, and the idler. In other embodiments, a series of permanent magnet bearings and a mechanical bearing configured to produce a clamping force. In one embodiment an electromagnetic bearing is coupled to a control system and produces a specified clamping force that is associated with a torque transmitted in the transmission during operation. In some embodiments, a mechanical load cam produces a clamping force proportional to torque, while a permanent magnet bearing provides a minimum clamping force.
1. An axial force generator for use with a continuously variable transmission (CVT) having a set of spherical power rollers arranged angularly about a main axis and in contact with a support member, the set of spherical power rollers being between and in contact with a first traction ring and a second traction ring, the main axis defining a longitudinal axis, the axial force generator comprising:
a permanent magnet bearing;
a first mechanical load cam coupled to the first traction ring and to the permanent magnet bearing; and
an electromagnetic bearing for receiving a rotational power, wherein the permanent magnet bearing is adapted to provide a force between the spherical power rollers, the first and second traction rings, and the support member.
2. The axial force generator of claim 1 , further comprising a spring for preloading the axial force generator.
3. The axial force generator of claim 1 , wherein the electromagnetic bearing is coupled to the first traction ring.
4. The axial force generator of claim 1 , wherein the first mechanical load cam is adapted to receive a rotational power.
5. The axial force generator of claim 1 , further comprising a second mechanical load cam coupled to the second traction ring and a torque coupling.
6. The axial force generator of claim 1 , further comprising a control system configured to receive signals from the CVT and determine a clamping force based on the received signals.
7. An axial force generator for use with a continuously variable transmission (CVT) having a set of spherical power rollers arranged angularly about a main axis and in contact with a support member, the set of spherical power rollers being between and in contact with a first traction ring and a second traction ring, the main axis defining a longitudinal axis, the axial force generator comprising:
a housing rotatable about the longitudinal axis;
a permanent magnet bearing; and
an electromagnetic bearing for receiving a rotational power, wherein the permanent magnet bearing is adapted to provide a force between the spherical power rollers, the first and second traction rings, and the support member.
8. The axial force generator of claim 7 , further comprising a control system configured to receive signals from the CVT and determine a clamping force based on the received signals.
9. An axial force generator for use with a continuously variable transmission (CVT) having a set of spherical power rollers arranged angularly about a main axis and in contact with a support member, the set of spherical power rollers being between and in contact with a first traction ring and a second traction ring, the main axis defining a longitudinal axis, the axial force generator comprising:
a permanent magnet bearing; and
an electromagnetic bearing for receiving a rotational power, wherein the permanent magnet bearing is adapted to provide a force between the spherical power rollers, the first and second traction rings, and the support member, and wherein the second traction ring is substantially non-rotatable about the longitudinal axis.
10. The axial force generator of claim 9 , further comprising a control system configured to receive signals from the CVT and determine a clamping force based on the received signals.
11. An axial force generator for use with a continuously variable transmission (CVT) having a set of spherical power rollers arranged angularly about a main axis and in contact with a support member, the set of spherical power rollers being between and in contact with a first traction ring and a second traction ring, the main axis defining a longitudinal axis, the axial force generator comprising:
a permanent magnet bearing;
an electromagnetic bearing for receiving a rotational power, wherein the permanent magnet bearing is adapted to provide a force between the spherical power rollers, the first and second traction rings, and the support member; and
a control system configured to receive signals from the CVT and determine a clamping force based on the received signals.
12. A method of controlling an axial force in a continuously variable transmission (CVT) using the axial force generator of claim 11 , the method comprising:
receiving, by the control system, a signal associated with an operating condition of the CVT;
determining a clamping force based on the received signal; and
configuring the axial force generator to provide the determined clamping force.
13. The method of claim 12 , wherein the axial force generator is configured to optimize the operating efficiency of the CVT.
14. The method of claim 12 , wherein the clamping force is a constant clamping force.
15. The method of claim 12 , wherein the clamping force is a minimum clamping force.
16. The method of claim 12 , wherein the signal comprises a signal indicative of one or more of torque, temperature, and component speed.
17. The method of claim 12 , wherein determining the clamping force based on the received signal comprises using an algorithm to determine an optimum clamping force.
18. The method of claim 12 , wherein configuring the axial force generator to provide the determined clamping force is performed dynamically.
19. The method of claim 12 , wherein the axial force generator is configured to provide a predetermined clamping force.