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US3583286A
Expired / Lapsed
US
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Improvements in radial-type hydraulic machines
Assignee: Consiglio Nazionale delle Richerche
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Filing: 1968-09-17
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Granted: 1971-06-08
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Expires: 1988-09-17
Abstract
Abstract A radial-type hydraulic machine has a number of sets of hydraulically interconnected cylinders, each set consisting of four cylinders, and a cam with which pistons in the cylinders cooperate. The cam has a number of lobes equal to the number of sets of cylinders. Each lobe is divided in profile into two symmetrical halves, each half comprising in sequence a first circular section, a first parabolic section, a spiral section, a second parabolic section, and a second circular section. This configuration ensures that the sum of the linear speeds of those pistons which are at any instant travelling in a working stroke is constant, and in turn that the swept volume is constant throughout the operating cycle. In a motor, the torque and rotational speed are therefore constant for a constant-pressure, constant-volume supply of hydraulic fluid.
Inventors
- 👤 Ruggero Chiappulini
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 04:04
CPC Classifications
F; F01; F01B; F01B1/00; F01B1/06; F01B1/0641; F01B1/0648; F01B1/062; F01B1/0624; F01B1/0627; F01B1/0668
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
236 words
A hydraulic motor comprising: a. a rotatable drive shaft, b. a central cam secured to the drive shaft, c. two sets of cylinders extending radially with respect to the drive shaft, each set comprising four cylinders, the cylinders of the two sets being arranged symmetrically around the drive shaft, d. a piston arranged for axial sliding movement within each cylinder and cooperating with the cam, e. hydraulic fluid inlet and outlet ports in the cylinders, hydraulic pilot means in each cylinder including a pilot port and a pilot conduit interconnecting the pilot port and the space above the piston in an adjacent cylinder, the piston in each cylinder acting as a slide value and sequentially closing the pilot port and connecting the pilot port to the inlet and outlet ports in the cylinder to control the flow of fluid to and from the adjacent cylinder; f. the cam having two lobes, each lobe being divided symmetrically into two portions and each portion comprising successively in profile a first circular section, a first parabolic section, a spiral section, a second parabolic section, and a second circular section, whereby at any moment in an operating cycle of the motor, the combined instantaneous speeds and hydraulic fluid flow rates of all pistons travelling on a working stroke are constant and equal respectively to the maximum piston speed and maximum flow rate attained in any cylinder during the operating cycle.
Claim 2
Dependent Claim
236 words
A hydraulic motor comprising: a. a rotatable drive shaft, b. a central cam secured to the drive shaft, c. two sets of cylinders extending radially with respect to the drive shaft, each set comprising four cylinders, the cylinders of the two sets being arranged symmetrically around the drive shaft, d. a piston arranged for axial sliding movement within each cylinder and cooperating with the cam, e. hydraulic fluid inlet and outlet ports in the cylinders, hydraulic pilot means in each cylinder including a pilot port and a pilot conduit interconnecting the pilot port and the space above the piston in an adjacent cylinder, the piston in each cylinder acting as a slide value and sequentially closing the pilot port and connecting the pilot port to the inlet and outlet ports in the cylinder to control the flow of fluid to and from the adjacent cylinder; f. the cam having two lobes, each lobe being divided symmetrically into two portions and each portion comprising successively in profile a first circular section, a first parabolic section, a spiral section, a second parabolic section, and a second circular section, whereby at any moment in an operating cycle of the motor, the combined instantaneous speeds and hydraulic fluid flow rates of all pistons travelling on a working stroke are constant and equal respectively to the maximum piston speed and maximum flow rate attained in any cylinder during the operating cycle.
Claim 3
Dependent Claim
23 words
Hydraulic motor as claimed in claim 1, wherein each first and second parabolic profile section extends over an angular width of 37* .
Claim 4
Dependent Claim
23 words
Hydraulic motor as claimed in claim 1, wherein each first and second circular profile sections extend over an angular width of 4* .
Claim 5
Dependent Claim
21 words
HyDraulic motor as claimed in claim 1, wherein each said spiral profile section extends over an angular width of 8* .
Claim 6
Dependent Claim
239 words
A hydraulic machine comprising: a. a rotatable drive shaft; b. a number of sets of cylinders extending radially with respect to the drive shaft, each set comprising four cylinders; c. hydraulic fluid inlet and outlet ports in each cylinder, d. a piston arranged for axial sliding movement within each cylinder, hydraulic pilot means in each cylinder including a pilot port and a pilot conduit interconnecting the pilot port and the space above the piston in an adjacent cylinder, the piston in each cylinder acting as a slide value and sequentially closing the pilot port and connecting the pilot port to the inlet and outlet ports in the cylinder to control the flow of fluid to and from the adjacent cylinder; e. a cam secured for rotation about the drive shaft axis relatively to the cylinders and having a number of lobes equal to the number of sets of cylinders, each lobe being similar to the others and being divided symmetrically into two portions that each comprise successively in profile a first circular section, a first parabolic section, a spiral section, a second parabolic section, and a second circular section, whereby at any moment in an operating cycle of the machine, the combine instantaneous speeds and hydraulic fluid flow rates of all pistons travelling on a working stroke are constant and equal respectively to the maximum piston speed and maximum flow rate attained in any cylinder during the operating cycle.
Claim 7
Dependent Claim
239 words
A hydraulic machine comprising: a. a rotatable drive shaft; b. a number of sets of cylinders extending radially with respect to the drive shaft, each set comprising four cylinders; c. hydraulic fluid inlet and outlet ports in each cylinder, d. a piston arranged for axial sliding movement within each cylinder, hydraulic pilot means in each cylinder including a pilot port and a pilot conduit interconnecting the pilot port and the space above the piston in an adjacent cylinder, the piston in each cylinder acting as a slide value and sequentially closing the pilot port and connecting the pilot port to the inlet and outlet ports in the cylinder to control the flow of fluid to and from the adjacent cylinder; e. a cam secured for rotation about the drive shaft axis relatively to the cylinders and having a number of lobes equal to the number of sets of cylinders, each lobe being similar to the others and being divided symmetrically into two portions that each comprise successively in profile a first circular section, a first parabolic section, a spiral section, a second parabolic section, and a second circular section, whereby at any moment in an operating cycle of the machine, the combine instantaneous speeds and hydraulic fluid flow rates of all pistons travelling on a working stroke are constant and equal respectively to the maximum piston speed and maximum flow rate attained in any cylinder during the operating cycle.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-06-07 | 1974-12-07 | 1975-06-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-06-07 | 1978-12-07 | 1979-06-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-06-07 | 1982-12-07 | 1983-06-08 | $7700.00 | Window Closed / Lapsed |