Tensioner with spring force control in a second bore

A tensioner for a passive tensioner system tensioning a span of chain or a belt comprising:

• a housing have a first axially extending bore with a first fluid input and a second axially extending bore with a second fluid input;
• a first piston slidably received by the first axially extending bore, the first piston comprising a body having a first end and second end;
• a first pressure chamber for biasing the first piston outwards from the housing, defined between the first piston and the first axially extending bore and in fluid communication with the first fluid input;
• a second piston slidably received within the second axially extending bore, the second piston comprising a body having an open end and a closed end, a bottom surface at the open end, a top surface at the closed end, and a hollow interior having an inner diameter;
• an internal piston slidably received within the second axially extending bore, the internal piston comprising a shaft connected to a body received within the hollow interior of the second piston, the body of the internal piston having a first end and a second end;
• a second piston spring received by the hollow interior of the second piston, the second piston spring having a first end in contact with the hollow interior of the second piston and a second end in contact with the top surface of the internal piston;
• an internal piston spring received in the second axially extending bore, the internal piston spring having a first end in contact with the internal piston and a second end in contact with the second axially extending bore;
• a second pressure chamber defined between the internal piston and the second axially extending bore, in fluid communication with the second fluid input;
• and
• a check valve between the second pressure chamber and the second fluid input;
• wherein when dynamic load from the chain or belt moves the first piston and the second piston inwards and outwards from the housing, fluid from the second fluid input is drawn into the second pressure chamber through the check valve, creating a fluid pressure in the second pressure chamber, causing the internal piston to move outwards from the housing and exert an outward force on the second piston through the second piston spring, opposing an inward force of the dynamic load.

A tensioner for a passive tensioner system tensioning a chain having a chain span or a belt comprising:

• a housing have a first bore with a first fluid input and a second bore with a second fluid input;
• a hollow moveable sleeve slidably received by the first bore comprising a hollow body defining a first open end and a second open end separated by an inner flange having a top surface, a bottom surface and a through hole;
• a first piston coaxially arranged within the moveable sleeve and received by the first open end of the movable sleeve;
• a piston spring in contact with the first piston for biasing the first piston outwards from the moveable sleeve, having a first piston spring end contacting the first piston and a second piston spring end contacting the top surface of a flange of the moveable sleeve;
• a bias spring received within the first bore of the housing and the hollow interior of the moveable sleeve, for biasing the moveable sleeve outwards from the housing, with a first bias spring end in contact with the bottom surface of the inner flange of the moveable sleeve and a second bias spring end;
• a first pressure chamber defined between the hollow moveable sleeve, hollow interior of the first piston the bias spring and the first bore of the housing and in fluid communication with the first fluid input;
• a second piston slidably received by the second bore of the housing and coupled to the moveable sleeve through a coupling;
• a second pressure chamber defined between the second piston and the second bore, in fluid communication with the second fluid input;
• a check valve between the second pressure chamber and the second fluid input;
• wherein when dynamic load from the chain or belt moves the first piston inwards and outwards from the housing, the second piston, coupled to the first piston, moves inwards into the housing and outwards into the housing, drawing fluid from the second fluid input and the check valve, into the second pressure chamber, creating a fluid pressure in the second pressure chamber, causing the movable sleeve to move outwards from the housing and exert an outward force on the first piston through the piston spring, opposing an inward force of the dynamic load.