US3721158A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electro hydraulic motors
Assignee: Consiglio Nazionale delle Richerche
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Filing: 1971-02-02
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Granted: 1973-03-20
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Expires: 1991-02-02
Abstract
Abstract An electro-hydraulic motor is described in which a rotary hydraulic motor is slaved to a stepping pilot motor by the operation of a fluid distributor valve which is controlled by a differential device responsive to the angular discrepancy between the shafts of the pilot and hydraulic motor. In this invention, the differential device consists of a toothed wheel coupled to the electric pilot motor to drive a shaft which is slidable coaxially and rotatable relative to the hydraulic motor shaft: a frontal cam carried by the latter shaft cooperates with a roller mounted on a face of the toothed wheel to cause proportional axial displacement of the differential shaft, which is transmitted to the spool of the distributor valve, preferably mounted at right angles to the hydraulic motor shaft.
Inventors
- 👤 Addea N D
- 👤 C Panzeri
- 👤 R Chiappulini
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 21:05
CPC Classifications
F; F15; F15B; F15B9/00; F15B9/14; F15B9/02; F15B9/08; F15B9/09
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
255 words
An electro-hydraulic motor of the type comprising a first stepping electric pilot motor and a rotary hydraulic power motor having respective shafts, a distributor valve having a movable stem which regulates the supply of working fluid to the hydraulic motor, and a differential device connected to said movable stem of the distributor valve to displace the latter proportionally to the angular discrepancy existing between the shaft of the electric pilot motor and the shaft of the hydraulic motor, wherein the improvement consists in: the differential device comprising a first toothed wheel coupled directly to the shaft of the electric pilot motor, a shaft of the differential device coaxial with the shaft of the hydraulic motor and on which a second toothed wheel meshing with the first toothed wheel is mounted: means supporting said shaft of the differential device for rotation and axial displacement relative to the hydraulic motor shaft and facing the second toothed wheel, and cam-follower means interposed between the frontal cam and said toothed wheel and supported by the latter; the distributor valve being disposed transversely of the shaft of the hydraulic motor and connected hydraulically to the hydraulic motor; transmitting means interconnecting said shaft of the differential device and the stem of the distributor valve and transforming axial movements, in either sense, of the said shaft of the differential device into corresponding axial movements of said stem; and elastic means acting on the said shaft of the differential device and said stem to maintain them always in contact with said transmitting means.
Claim 2
Dependent Claim
255 words
An electro-hydraulic motor of the type comprising a first stepping electric pilot motor and a rotary hydraulic power motor having respective shafts, a distributor valve having a movable stem which regulates the supply of working fluid to the hydraulic motor, and a differential device connected to said movable stem of the distributor valve to displace the latter proportionally to the angular discrepancy existing between the shaft of the electric pilot motor and the shaft of the hydraulic motor, wherein the improvement consists in: the differential device comprising a first toothed wheel coupled directly to the shaft of the electric pilot motor, a shaft of the differential device coaxial with the shaft of the hydraulic motor and on which a second toothed wheel meshing with the first toothed wheel is mounted: means supporting said shaft of the differential device for rotation and axial displacement relative to the hydraulic motor shaft and facing the second toothed wheel, and cam-follower means interposed between the frontal cam and said toothed wheel and supported by the latter; the distributor valve being disposed transversely of the shaft of the hydraulic motor and connected hydraulically to the hydraulic motor; transmitting means interconnecting said shaft of the differential device and the stem of the distributor valve and transforming axial movements, in either sense, of the said shaft of the differential device into corresponding axial movements of said stem; and elastic means acting on the said shaft of the differential device and said stem to maintain them always in contact with said transmitting means.
Claim 3
Dependent Claim
34 words
Motor according to claim 1, in which the shaft of the hydraulic motor has a cylindrical bore and including a circulating ball bearing in said bore supporting the shaft of the differential device radially.
Claim 4
Dependent Claim
38 words
Motor according to claim 2, including a thrust bearing located at the axially inner end of said bore in the hydraulic motor shaft and a spring located between such thrust bearing and the shaft of the differential device.
Claim 5
Dependent Claim
47 words
Motor according to claim 2, wherein the axially outer end of said cylindrical bore is threaded and carries a correspondingly threaded tubular member arranged coaxially with the shaft of the differential device, the said frontal cam being formed integrally on the axially outer end of said member.
Claim 6
Dependent Claim
50 words
Motor according to claim 1, wherein the cam-follower means comprise a rotatable roller the axis of which extends radially with respect to the second toothed wheel and a small shaft carrying said roller and supported by the said toothed wheel on the surface of the latter facing the frontal cam.
Claim 7
Dependent Claim
84 words
Motor according to claim 1, wherein the transmitting means comprise a right angled lever pivotally mounted on the hydraulic motor for rocking movement about an axis perpendicular to the plane containing the axes of the shaft of the differential device and the stem of the distributor valve, the said lever being in contact on one side with the outer end of said shaft of the differential device and on the other side with the outer end of the said stem outside the distributor valve.
Claim 8
Dependent Claim
184 words
Motor according to claim 3, wherein the transmitting means comprise a right-angled lever pivotally mounted on the hydraulic motor for rocking movement about an axis perpendicular to the plane containing the axes of the shaft of the differential device and the stem of the distributor valve, the said Lever being in contact on one side with the outer end of said shaft of the differential device and on the other side with the outer end of the said stem outside the distributor valve, and wherein the distributor valve has an end plate, the elastic means for maintaining the shaft of the differential device and the stem of the distributor valve always in contact with the right-angled lever comprising two helical springs the first of which is the spring located within said cylindrical bore of the hydraulic motor shaft between the inner end of the shaft of the differential device and the thrust bearing, and the second of which is interposed between the end of the distributor valve stem opposite to that cooperating with the right-angled lever and the end plate of the distributor valve.
Claim 9
Dependent Claim
15 words
Motor according to claim 7, including presettable means varying the pre-loading of the said springs.
Claim 10
Dependent Claim
108 words
Motor according to claim 8, wherein said presettable means varying the pre-loading of the springs comprise a first screw passing through said end plate of the distributor valve a plate through which said first screw, cooperates with an end of the spring disposed inside the valve and a second screw disposed coaxially with the shaft of the hydraulic motor and mounted inside the latter in cooperation with the thrust bearing supporting the shaft of the differential device to vary the axial position of the said bearing inside the bore of the hydraulic motor shaft, means being provided for adjusting the said first and second screws from the outside.
Claim 11
Dependent Claim
21 words
Motor according to claim 1, including a replaceable shock-absorbing member through which the distributor valve is connected to the hydraulic motor.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-03-19 | 1976-09-18 | 1977-03-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-19 | 1980-09-18 | 1981-03-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-19 | 1984-09-18 | 1985-03-20 | $7700.00 | Window Closed / Lapsed |