초록 ▼

A hydraulic drive system and a bicycle having such system as its drive train, the system including a pump, preferably a vane pump, operably connected to the bicycle pedal crank, the pump delivering pressurized fluid to a hydraulic motor operably connected to the wheel or mechanism to be driven, e.g.

A hydraulic drive system and a bicycle having such system as its drive train, the system including a pump, preferably a vane pump, operably connected to the bicycle pedal crank, the pump delivering pressurized fluid to a hydraulic motor operably connected to the wheel or mechanism to be driven, e.g., the bicycle drive wheel. The pump has an impeller eccentrically disposed in a housing, and a piston-cylinder mechanism is provided to change the eccentricity of the pump impeller with respect to the pump housing as a function of hydraulic system pressure, to thereby maintain a constant input force, e.g., pedal pressure, and rotation rate, for a wide range of speeds. The motor also has an impeller eccentrically disposed in a housing, and a spacer bar connected between the pump and motor housings automatically adjusts the motor impeller eccentricity with changes in the pump impeller eccentricity, thereby further maintaining constant pedal pressure and rotation rate for a wide range of speeds. A pretensioned spring opposes the movement of the piston in the cylinder, thereby requiring that a predetermined pedal pressure level be exerted before the pump and motor eccentricities will change. A lever is provided for manually setting, and varying, the pretension of the spring to thereby set the pedal pressure level at which the pump and motor impeller eccentricities will be charged.

대표청구항 ▼

1. In a bicycle having a frame for supporting at least one drive wheel, pedals mounted on a drive crank for applying power to propel the bicycle, and a crank housing carried on said frame and having means for rotatably mounting said crank, the improvement comprising: hydraulic motor means operabl

1. In a bicycle having a frame for supporting at least one drive wheel, pedals mounted on a drive crank for applying power to propel the bicycle, and a crank housing carried on said frame and having means for rotatably mounting said crank, the improvement comprising: hydraulic motor means operably connected to said drive wheel to rotatably drive said wheel, said motor means having fluid inlet and outlet ports; a vane-type hydraulic pump having inlet and outlet ports, a housing, and an impeller eccentrically positioned within said housing and operatively connected to said crank for rotation therewith; fluid conduit means coupling the pump outlet port to the motor inlet port and coupling the pump inlet port to the motor outlet port; and means for adjusting the eccentricity of said impeller in said housing as said fluid pressure changes in response to changed load, so as to maintain a constant pedal force for rotation of said crank and of said impeller under a range of load conditions, including: a cylinder fixed in position with respect to said pump housing and in fluid communication with the pressure side of said pump; a piston means movably received within said cylinder to move as the pressure in said cylinder changes, said piston means operatively connected to said bicycle frame so that said piston means forces said pump housing to move relative to said impeller as the cylinder pressure changes, thereby adjusting said eccentricity as a function of said pressure changes; biasing means to bias said piston means and housing against movement as pressure increases; and manual means to selectively adjust the force exerted by said biasing means against said piston means and housing to thereby raise or lower the amount of pressure required in said cylinder to change said eccentricity. 2. The improvement for a bicycle as defined in claim 1 wherein said piston means is secured to said crank housing of said frame by a first bracket attached to said crank housing, wherein said cylinder is attached to said pump housing, wherein said biasing means is disposed between said first bracket and a second bracket attached to said pump housing, and wherein said manual means comprises a lever pivotally attached to said first bracket, said biasing means being disposed to act upon the lever such that pivotal movement of said lever is applied to said biasing means and is transmitted thereby to said first bracket and said piston means. 3. A bicycle as defined in claim 2 which further comprises a pump housing suspension mechanism including a first suspension bracket attached to said crank housing, a second suspension bracket attached to said pump housing, and a suspension member pivotally attached to said suspension stand and to said suspension bracket such that said housing is pivoted on said suspension member by said piston and said cylinder means through said biasing means to move said housing relative to said impeller in a manner which changes said eccentricity. 4. A bicycle as defined in claim 3 which further comprises at least two stop means, one of said stop means for preventing pivotal movement of said housing in one direction beyond a first predetermined point, the other of said stop means for preventing pivotal movement of said housing in a second direction beyond a second predetermined point. 5. A bicycle as defined in claim 1 wherein said hydraulic motor means comprises a vane-type motor, said motor including a housing having inlet and outlet ports and having a generally cylindrical cavity therein in fluid communication with said ports, a generally cylindrical impeller eccentrically disposed within said cavity and having a diameter less than the diameter of said cavity, means for physically connecting said impeller with said drive wheels for rotation of said drive wheels as said impeller is turned, a plurality of vane means projecting outward from said impeller toward the surfaces of said cavity, said vane means defining a plurality of chambers between said housing and said impeller, each of said chambers during rotation of said impeller sequentially and progressively expanding in volume due to said eccentricity and each of said expanding chambers being in fluid communication with said motor inlet port, said expanding chambers receiving pressurized fluid from said pump through said inlet port forcing said impeller to rotate, said chambers then sequentially and progressively contracting in volume upon impeller rotation and each of said contracting chambers coming into fluid communication with said outlet port during impeller rotation, said conduit means connecting said outlet port of said motor to said inlet port of said pump, said contracting motor chambers forcing said fluid through said motor outlet port and through said conduit into said pump inlet port. 6. The bicycle as defined in claim 5 which further comprises means for adjusting said eccentricity of said motor impeller with respect to said motor housing. 7. The bicycle as defined in claim 6 wherein said means for adjusting said eccentricity of said motor housing with respect to said motor impeller comprises a spacer bar fixedly attached to one end to said pump housing and at the other end to said motor housing, such that movement of said pump housing forces said motor housing to move thereby changing the eccentricity of said motor housing with respect to said impeller. 8. The bicycle as defined in claim 7 wherein said spacer bar maintains the eccentricity of said motor housing with respect to said motor impeller in predetermined relationship to the eccentricity of said pump housing with respect to said pump impeller. 9. In a bicycle having a frame for supporting at least one drive wheel, pedals mounted on a drive crank for applying power to propel the bicycle, said crank rotatably mounted within a crank housing carried on said frame, the improvement comprising: a hydraulic motor means operably connected to rotatably drive said drive wheel, said motor means having fluid inlet and outlet ports; a hydraulic pump having inlet and outlet ports, and fluid conduit means coupling the pump outlet port to the motor inlet port and coupling the pump inlet port to the motor outlet port; said pump including a housing having a generally cylindrical cavity in fluid communication with said pump inlet and outlet ports, a rotatable impeller eccentrically disposed within said cavity and operably connected with said crank for rotation thereby as said crank is turned; said motor including a housing providing said inlet and outlet ports and having a generally cylindrical cavity therein in fluid communication with said ports, said motor having a generally cylindrical impeller eccentrically disposed within said cavity, and means for physically connecting said impeller with said drive wheels for rotation of said drive wheels as said impeller is turned; and means for adjusting the eccentricity of at least one of said impellers with respect to its housing, including a cylinder attached to said housing and in fluid communication therewith; a piston slidably received within said cylinder with one end of said piston operably connected to said frame; biasing means to bias said piston toward one position in said cylinder; and manual means to selectively adjust said biasing means, whereby said piston and cylinder will move said housing with respect to said impeller against the force of said biasing means when the fluid pressure in said housing changes and the particular pressure at which said piston will respond to move said housing may be selectively changed by said manual means. 10. In a bicycle having a frame for supporting at least one drive wheel, pedals mounted on a drive crank for applying power to propel the bicycle, said crank rotatably mounted within a crank housing carried on said frame, the improvement comprising: a hydraulic motor means operably connected to rotatably drive said drive wheel, said motor means having fluid inlet and outlet ports; a hydraulic pump having inlet and outlet ports, and fluid conduit means coupling the pump outlet port to the motor inlet port and coupling the pump inlet port to the motor outlet port; said pump including a housing having a generally cylindrical cavity in fluid communication with said pump inlet and outlet ports, a rotatable impeller eccentrically disposed within said cavity and operably connected with said crank for rotation thereby as said crank is turned; said motor including a housing providing said inlet and outlet ports and having a generally cylindrical cavity therein a fluid communication with said ports, said motor having a generally cylindrical impeller eccentrically disposed within said cavity, and means for physically connecting said impeller with said drive wheels for rotation of said drive wheels as said impeller is turned; means interconnecting said pump and said motor to maintain selected relative amounts of impeller-to-housing eccentricity therebetween; and pressure-responsive means associated with one of said pump and motor housings to adjust the eccentricity of said one housing with respect to its impeller, said pressure-responsive means located at least partially outside said housing and having manually actuable means to select the pressure level at which said pressure-responsive means responds to adjust said eccentricity.