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US 6,655,933 B2Granted
CAM operated fuel pump with split function follower springs
AssigneeMikuni Corporation
InventorNoriaki Chiba
Life of this patent
Estimating the term…
Abstract
In order to provide a fuel pump in which a piston spring arrangement can be made of inexpensive material, knocking noises of a piston are reduced, and components related to the piston are protected against breakdown, a piston-following spring is provided between a fuel pump body and the piston to lower the piston in response to the rotation of an eccentric cam. A pumping member-moving spring is provided between the fuel pump body and a pin connected to a pumping member, and lowers the pumping member when the piston is moved down. The downward movements of the piston and the pumping member are caused by the springs, so that these springs can be made of inexpensive materials, and enable the piston to reliably follow the eccentric cam.
Claims23
A fuel pump for pumping fuel in response to rotation of an eccentric cam, said fuel pump comprising:
- a fuel pump body having a pump chamber;
- a pumping member movably provided at said pump chamber for pressurizing and depressurizing said pump chamber, said pumping member being movable between a first pumping member position and a second pumping member position;
- a piston movably mounted to said fuel pump body and being arranged to be operably engaged with the eccentric cam for movement between first and second ends of a piston stroke, said piston being operably coupled to said pumping member so that said pumping member is caused to move toward said first pumping member position due to said piston moving toward said first end of said piston stroke, and toward said second pumping member position due to said piston moving toward said second end of said piston stroke;
- a piston following spring operably engaged with said piston to urge said piston toward said first end of the piston stroke;
- a pumping member-moving spring operably engaged with said pumping member to independently urge said pumping member toward said first pumping member position;
- and
- wherein said piston-following spring and said pumping member-moving spring are disposed in parallel with each other.
4 more elements
A fuel pump for pumping fuel in response to rotation of an eccentric cam, said fuel pump comprising:
- a fuel pump body having a pump chamber;
- a pumping member movably provided at said pump chamber for pressurizing and depressurizing said pump chamber, said pumping member being movable between a first pumping member position and a second pumping member position;
- a piston movably mounted to said fuel pump body and being arranged to be operably engaged with the eccentric cam for movement between first and second ends of a piston stroke, said piston being operably coupled to said pumping member so that said pumping member is caused to move toward said first pumping member position due to said piston moving toward said first end of said piston stroke, and toward said second pumping member position due to said piston moving toward said second end of said piston stroke;
- a piston-following spring operably engaged with said piston to urge said piston toward said first end of the piston stroke;
- a pumping member-moving spring operably engaged with said pumping member to urge said pumping member toward said first pumping member position;
- and
- a pumping member spring mechanism urging said pumping member toward said second pumping member position.
4 more elements
A fuel pump for pumping fuel in response to rotation of an eccentric cam, said fuel pump comprising:
- a fuel pump body having a pump chamber;
- a pumping member movably provided at said pump chamber for pressurizing and depressurizing said pump chamber, said pumping member being movable between a first pumping member position and a second pumping member position;
- a piston movably mounted to said fuel pump body and being arranged to be operably engaged with the eccentric cam for movement between first and second ends of a piston stroke, said piston being operably coupled to said pumping member so that said pumping member is caused to move toward said first pumping member position due to said piston moving toward said first end of said piston stroke and toward said second pumping member position due to said piston moving toward said second end of said piston stroke;
- a piston-following spring operably engaged with said piston to urge said piston toward said first end of the piston stroke;
- a pumping member-moving spring operably engaged with said pumping member to urge said pumping member toward said first pumping member position;
- a first engagement member coupled to said pumping member;
- a second engagement member provided at said piston and being arranged for engagement with said first engagement member;
- and
- a plate member positioned between said first engagement member and said pumping member-moving spring so as to be urged by said pumping member-moving spring toward said first engagement member.
6 more elements
A fuel pump for pumping fuel in response to rotation of an eccentric cam, said fuel pump comprising:
- a fuel pump body having a pump chamber;
- a pumping member movably provided at said pump chamber for pressurizing and depressurizing said pump chamber said pumping member being movable between a first pumping member position and a second pumping member position;
- a piston movably mounted to said fuel pump body and being arranged to be operably engaged with the eccentric cam for movement between first and-second ends of a piston stroke, said piston being operably coupled to said pumping member so that said pumping member is caused to move toward said first pumping member position due to said piston moving toward said first end of said piston stroke, and toward said second pumping member position due to said piston moving toward said second end of said piston stroke;
- a piston-following spring operably engaged with said piston to urge said piston toward said first end of the piston stroke;
- a pumping member-moving spring operably engaged with said pumping member to independently urge said pumping member toward said first pumping member position;
- a first engagement member coupled to said pumping member so as to be movable therewith;
- and
- wherein said pumping member-moving spring is operably engaged with said first engagement member and urges said first engagement member to move in a direction to cause said pumping member to move toward said first pumping member position.
5 more elements
A fuel pump for pumping fuel in response to rotation of an eccentric cam, said fuel pump comprising:
- a fuel pump body having a pump chamber;
- a diaphragm secured to said fuel pump body and movable between a pump chamber pressurizing position and a pump chamber depressurizing position;
- a piston reciprocally mounted to said fuel pump body for movement between an extended position and a retracted position, said piston being arranged to be operably engaged with the eccentric cam so as to be movable upon operation thereof, and said piston being operably coupled to said diaphragm so that at least some movements of said piston cause movements of said diaphragm;
- a spring arrangement including a piston-following spring urging said piston toward said extended position, and a diaphragm-moving spring independently said diaphragm toward said pump chamber depressurizing position, said piston-following spring and said diaphragm-moving spring being disposed in parallel with each other.
1 more element
A fuel pump for pumping fuel in response to rotation of an eccentric cam, said fuel pump comprising:
- a fuel pump body having a pump chamber;
- a diaphragm secured to said fuel pump body and movable between a pump chamber pressurizing position and a pump chamber depressurizing position;
- a piston reciprocally mounted to said fuel pump body for movement between an extended position and a retracted position, said piston being arranged to be operably engaged with the eccentric cam so as to be movable upon operation thereof, and said piston being operably coupled to said diaphragm so that at least some movements of said piston cause movements of said diaphragm;
- a spring arrangement including a piston-following spring urging said piston toward said extended position, and a diaphragm-moving spring urging said diaphragm toward said pump chamber depressurizing position;
- a first engagement member coupled to said diaphragm;
- a second engagement member provided at said piston and being arranged to engage with said first engagement member;
- and
- a plate member positioned between said first engagement member and said diaphragm-moving spring, said plate member being movable with respect to said first engagement member.
5 more elements
A fuel pump for pumping fuel in response to rotation of an eccentric cam, said fuel pump comprising:
- a fuel pump body having a pump chamber;
- a diaphragm secured to said fuel pump body and movable between a pump chamber pressurizing position and a pump chamber depressurizing position;
- a piston reciprocally mounted to said fuel pump body for movement between an extended position and a retracted position, said piston being arranged to be operably engaged with the eccentric cam so as to be movable upon operation thereof, and said piston being operably coupled to said diaphragm so that at least some movements of said piston cause movements of said diaphragm;
- a spring arrangement including a piston-following spring urging said piston toward said extended position, and a diaphragm-moving spring independently urging said diaphragm toward said pump chamber depressurizing position;
- said first engagement member comprises a pin;
- and
- said second engagement member comprises an elongated groove formed in said piston, said pin being movably engaged in said elongated groove.
4 more elements
A fuel pump for pumping fuel in response to rotation of an eccentric cam, said fuel pump comprising:
- a fuel pump body having a pump chamber;
- a diaphragm secured to said fuel pump body and movable between a pump chamber pressurizing position add a pump chamber depressurizing position;
- a piston reciprocally mounted to said fuel pump body for movement between an extended position and a retracted position, said piston being arranged to be operably engaged with the eccentric cam so as to be movable upon operation thereof, and said piston being operably coupled to said diaphragm so that at least some movements of said piston cause movements of said diaphragm;
- and
- a spring arrangement including a piston-following spring urging said piston toward said extended position, a diaphragm-moving spring urging said diaphragm toward said pump chamber depressurizing position, and a diaphragm spring urging said diaphragm toward said pump chamber pressurizing position.
2 more elements
A fuel pump for pumping fuel in response to rotation of an eccentric cam, said fuel pump comprising:
- a fuel pump body having a pump chamber;
- a diaphragm secured to said fuel pump body and movable between a pump chamber pressurizing position and a pump chamber depressurizing position;
- a piston reciprocally mounted to said fuel pump body for movement between an extended position and a retracted position, said piston being arranged to be operably engaged with the eccentric cam so as to be movable upon operation thereof, and said piston being operably coupled to said diaphragm so that at least some movements of said piston cause movements of said diaphragm;
- a spring arrangement including a piston-following spring urging said piston toward said extended position, and a diaphragm-moving spring independently urging said diaphragm toward said pump chamber depressurizing position, both said piston-following spring and said diaphragm-moving spring being disposed on a side of said diaphragm opposite said pump chamber.
1 more element
A fuel pump for pumping fuel in response to rotation of an eccentric cam, said fuel pump comprising:
- a fuel pump body having a pump chamber;
- a pumping member movably provided at said pump chamber for pressurizing and depressurizing said pump chamber, said pumping member being movable between a first pumping member position and a second pumping member position;
- a piston movably mounted to said fuel pump body and being arranged to be operably engaged with the eccentric cam for movement between first and second ends of a piston stroke, said piston being operably coupled to said pumping member so that said pumping member is caused to move toward said first pumping member position due to said piston moving toward said first end of said piston stroke, and toward said second pumping member position due to said piston moving toward said second end of said piston stroke;
- a piston-following spring operably engaged with said piston to urge said piston toward said first end of the piston stroke;
- a pumping member-moving spring operably engaged with said pumping member to independently urge said pumping member toward said first pumping member position;
- and
- wherein both said piston-following spring and said pumping member-moving spring are disposed on a side of said pumping member opposite said pump chamber.
4 more elements
Dependencies are inferred from the claim text.