TOROIDAL CONTINUOUSLY VARIABLE TRANSMISSION

• US 20080305920A1
• Filed: 06/05/2008
• Published: 12/11/2008
• Est. Priority Date: 06/06/2007
• Status: Active Grant

• Current Assignee: NSK Limited
• Original Assignee: NSK Limited
• Inventors: IMANISHI, Takashi, NISHII, Hiroki
• Granted Patent: US 9,188,206 B2
• Time in Patent Office: Days
• US Class Current: 476/42
• CPC Class Codes: F16H 15/38 with two members B having hollow toroid surfaces opposite to each other, the member or members A being adjustably mounted between the surfaces
• CPC Class Codes: Y10T 29/49464 Assembling of gear into force transmitting device

Abstract

Power roller-side concave grooves are opposed to disk-side concave grooves 19, 19 so as to have angles therebetween in a rolling contact area between a peripheral surface of the power roller and a one-side surface 17 of a disk 16 in an axial direction regardless of a transmission gear ratio of a toroidal continuously variable transmission. Accordingly, the disk-side concave grooves 19, 19 are formed so as to have angles with respect to a circumferential direction of the disk 16 when viewed from a normal direction relative to the one-side surface 17 in the axial direction. Meanwhile, the power roller-side concave grooves are formed into a concentric shape (or a spiral shape) about a central shaft of the power roller. As a result, it is possible to prevent a decrease of a contact area in the rolling contact area regardless of the transmission gear ratio.

Claims

1. A toroidal continuously variable transmission, comprising:

a pair of disks having an axially one-side surface of which sectional shape is toroidal, respectively, the disks being supported rotatably and concentrically with each other in a state that the respective axially one-side surface opposes to each other; and

a plurality of power rollers arranged along with a circumferential direction of the disks between the respective axially one-side surface, the respective power rollers having a peripheral surface being made contact with the axially one-side surface of the disk, wherein

plurality of disk-side concave grooves are formed on the axially one-side surface of the disk,

plurality of power roller-side concave grooves are formed on the peripheral surface of the power roller and

regardless of a transmission ratio, at a rolling contact area between the disk and the power roller, the disk-side concave grooves and the power roller-side grooves are in a distortional relation.

2. The toroidal continuously variable transmission, as set forth in claim 1, wherein

the disk-side concave grooves are formed on only a radially part of the axially one-side surface of the disk so that the disk-side concave grooves do not continuously meet with the power roller-side concave grooves.

3. The toroidal continuously variable transmission, as set forth in claim 1, wherein

at the rolling contact area, when viewed from a normal direction relative to the rolling contact area, the disk-side concave grooves intersect with the power roller-side concave grooves at angles of 5 to 90 degree.

4. The toroidal continuously variable transmission, as set forth in claim 3, wherein

at the rolling contact area, when viewed from a normal direction relative to the rolling contact area, the disk-side concave grooves intersect with the power roller-side concave grooves at angles of 5 to 45 degree.

5. The toroidal continuously variable transmission, as set forth in claim 1, wherein

when viewed from a normal direction relative to a surface on which the respective concave grooves are formed, at least one of the disk-side concave grooves and the power roller-side concave grooves intersects with a circumferential direction of the disk or the power roller at certain angles and

the concave grooves are arranged such that the angle defined between the concave groove of radially inner side and the circumferential direction is larger than the angle defined between the concave groove of radially outer side.

6. A toroidal continuously variable transmission, comprising:

a pair of disks having an axially one-side surface of which sectional shape is toroidal, respectively, the disks being supported rotatably and concentrically with each other in a state that the respective axially one-side surface opposes to each other; and

a plurality of power rollers arranged along with a circumferential direction of the disks between the respective axially one-side surface, the respective power rollers having a peripheral surface being made contact with the axially one-side surface of the disk, wherein

plurality of disk-side concave grooves are formed on the axially one-side surface of the disk,

plurality of power roller-side concave grooves are formed on the peripheral surface of the power roller,

when viewed from a normal direction relative to a surface on which the respective concave grooves are formed, at least one of the disk-side concave grooves and the power roller-side concave grooves intersects with a circumferential direction of the disk or the power roller at certain angles and

the concave grooves are arranged such that the angle defined between the concave groove of radially inner side and the circumferential direction is larger than the angle defined between the concave groove of radially outer side.

7. A manufacturing method of a toroidal continuous variable transmission which comprises:

a pair of disks having an axially one-side surface of which sectional shape is toroidal, respectively, the disks being supported rotatably and concentrically with each other in a state that the respective axially one-side surface opposes to each other; and

a plurality of power rollers arranged along with a circumferential direction of the disks between the respective axially one-side surface, the respective power rollers having a peripheral surface being made contact with the axially one-side surface of the disk, wherein

plurality of disk-side concave grooves are formed on the axially one-side surface of the disk,

plurality of power roller-side concave grooves are formed on the peripheral surface of the power roller,

when viewed from a normal direction relative to a surface on which the respective concave grooves are formed, at least one of the disk-side concave grooves and the power roller-side concave grooves intersects with a circumferential direction of the disk or the power roller at certain angles and

the concave grooves are arranged such that the angle defined between the concave groove of radially inner side and the circumferential direction is larger than the angle defined between the concave groove of radially outer side,

the manufacturing method comprising;

rotating a work, to which the concave groove are formed, at a constant speed;

bringing a tool for forming the concave groove to a worked surface of the work and

moving the tool in a radial direction of the work at a constant speed while rotating the work at constant speed and keeping a contact between the tool and the work.