Anti-return system for hydraulic tensioner
AssigneeBorgWarner Inc.
InventorYoung Taek SUN
Life of this patent
Estimating the term…
Abstract
A hydraulic tensioner includes piston retaining, anti-return, and anti-rotation functions. A ratchet clip for the tensioner preferably has straight sides or legs substantially perpendicular to a connecting portion. The ratchet clip preferably is substantially rectangular or U-shaped. The ends of the ratchet clip opposite the connecting portion are preferably bent inwards after the ratchet clip has been assembled on the tensioner. The ratchet clip performs the piston retaining function, the anti-rotation function and the anti-return functions. It is unnecessary for the user to remove the ratchet clip after the tensioner is assembled on the engine.
Claims18
A hydraulic tensioner, comprising:
- a tensioner body having a bore in fluid communication with a source of pressurized fluid through an inlet;
- a hollow piston slidably received within the bore, with an outer diameter comprising a plurality of teeth, an extension end of the piston having at least one first flat top surface;
- a hydraulic pressure chamber defined by the hollow piston and the bore of the tensioner body;
- a piston spring received within the hydraulic pressure chamber for biasing the piston away from the inlet;
- and
- a substantially U-shaped ratchet clip inserted in a first hole and a second hole in the tensioner body such that the ratchet clip at least partially surrounds an outer diameter of the piston.
A method of controlling piston movement in a tensioner comprising a tensioner body having a bore in fluid communication with a source of pressurized fluid through an inlet, a hollow piston slidably received within the bore, with an outer diameter comprising a plurality of ratchet teeth, an extension end of the piston having at least one first flat top surface, a hydraulic pressure chamber defined by the hollow piston and the bore of the tensioner body, a piston spring received within the hydraulic pressure chamber for biasing the piston away from the inlet, and a ratchet clip comprising two legs parallel to each other, a connecting section perpendicular to the legs that connects the two legs, and a bendable section at an end of each leg opposite the connecting section, comprising the step of:
- preventing retraction of the piston more than a set backlash amount, wherein the ratchet clip acts as a non-return mechanism coupled to the piston, wherein the non-return mechanism comprises the plurality of ratchet teeth formed along a length of the piston contacting the legs of the ratchet clip, such that the piston extends, but does not retract more than the set backlash amount.
A ratchet clip for a tensioner comprising a tensioner body having a bore in fluid communication with a source of pressurized fluid through an inlet, a hollow piston slidably received within the bore, with an outer diameter comprising a plurality of teeth, an extension end of the piston having at least one first flat top surface, a hydraulic pressure chamber defined by the hollow piston and the bore of the tensioner body, a piston spring received within the hydraulic pressure chamber for biasing the piston away from the inlet, the ratchet clip comprising two legs parallel to each other, a connecting section perpendicular to the legs that connects the two legs, and a bendable section at an end of each leg opposite the connecting section.
Dependencies are inferred from the claim text.