US3838654A

US3838654A - Submarine craft

Info

Publication number: US3838654A
Application number: US00213882A
Authority: US
Inventors: J Haas
Original assignee: Bruker Biospin GmbH
Current assignee: Bruker Biospin GmbH
Priority date: 1971-12-30
Filing date: 1971-12-30
Publication date: 1974-10-01
Anticipated expiration: 1991-10-01

Abstract

A submarine craft with hydraulic energy transmission system which receives its energy from a converter which converts electrical energy to hydraulic energy. The hydraulic energy is subsequently employed for driving at least one propeller by an axial piston engine; for fine adjustment of a buoyancy system of the craft; and for operating trim devices to alter the center of gravity of the craft. A sliding ring seal is employed to seal the shaft driving the propeller towards the interior of the hydraulic motor. A leak water collecting chamber sealed against the outboard water is provided on that side of the sealing ring which faces the water and is connected to a leak-water tank whose internal pressure is maintained at a predetermined value.

Description

United States Patent 1 1 Haas 1451 Oct. 1, 1974 SUBMARINE CRAFT [75] Inventor:

[73] Assignee: Bruker-Physik AG, Karlsruhe,

Germany 22 Filed: Dec. 30, 1971 21 Appl. No.: 213,882

Jorg Haas, Neureut, Germany 115/34 R, 34 A, 18 E; 308/363 3,665,884 5/1972 Gustafson 114/16 E Primary ExaminerTrygve M. Blix Assistant ExaminerGalen L. Barefoot Attorney, Agent, or FirmCraig & Antonelli [5 7] ABSTRACT A submarine craft with hydraulic energy transmission system which receives its energy from a converter which converts electrical energy to hydraulic energy. The hydraulic energy is subsequently employed for driving at least one propeller by an axial piston engine; for fine adjustment of a buoyancy system of the craft;

5 References Cited and for operating trim devices to alter the center of UNITED STATES PATENTS gravity of the craft. A sliding ring seal is employed to seal the shaft driving the propeller towards the interior a i of the hydraulic motor. A leak water collecting cham- 10/1942 gg gg 308/36'3 ber sealed against the outboard water is provided on 3202388 8/1965 115/34 that side of the sealing ring which faces the water and 3:301:209 1/1967 Caldwell 114/16 E is connected 3 leak-Water tank Whose internal P 3,467,050 9/1969 Herbert 308/363 sure is maintained at a p e rmined value. 3,587,511 6/1971 Buddrus 115/34 A 3,635,183 1 1972 Keatings 114/16 R 7 Clams, 3 Drawmg 27 --L Q r II II I? It? PAYENIEBUBT H914 3838.654 I mm 30v 5 INVENTOR 35R 6 HAA 5 BY Gala, MtowzQQc QH-LQQ ATTORNEYS SUBMARINE CRAFT The present invention relates to a submarine craft having a tight pressure hull and at least one propeller which is driven by a motor supplied with energy from an energy source provided for that purpose.

In conventional submarine craft, the various consumers are generally supplied with energy in the form of electric power. The propellers by which the craft is propelled and/or manoeuvered are, for instance, driven by electric motors. These electric motors are usually located inside the pressure hull and the drive shafts are passed through the pressure hull in a sealed arrangement. This has the drawback that seals for rotating shafts must be provided with are subject to the outboard pressure which may be very high in some cases. Another drawback consists in that the shafts and seals transmit the structure-borne noise of the motors to the pressure hull which acts like a resonant cavity radiating the noise toward the inside and outside. This noise radiation is a general nuisance and, in particular, a considerable stress and burden for the crew of the submarine craft. Prior art systems also include outboard electric motors whereby the drawbacks of passing the shafts through the pressure hull are avoided. However, a drawback which all electric motor drives have in common consists in that these have a very high flywheel effect, which means that manoeuvring is difficult with electric motors, because owing to their moment of inertia electric motors will not stop instantly when they are switched off or will not attain their new speed or sense of rotation very quickly when they are reversed, thus impairing the manoeuvrability of the submarine craft.

I The outboard electric motors of the prior art are threephase a.c. motors which cannot be supplied directly from the battery aboard the craft, but require either rotary converters or thyristor converters which latter tend to generate awkward voltage peaks in the supply system of the craft.

It is the object of the present invention to provide an improved energy system for submarine craft.

In accordance with the present invention, this object is accomplished by providing the submarine craft with a hydraulic energy transmission system which receives its energy from a converter fed by the energy source and supplies it to consumers and to which are connected hydraulic motors which drive the propellers. A special advantage of the submarine craft in accordance with the present invention consists in that it is highly manoeuvrable because owing to their very low moment of inertia, which is only about one tenth of that of electric motors, the hydraulic propulsion units respond.

very quickly to a reversal of the sense of rotation and a change in speed. Speed and sense of rotation of a plurality of propulsion units may be changed independently by means of spacesaving, uncomplicated commercially available hydraulic control components. An added advantage consists in that the motor may be located outside the pressure hull, thus obviating the need of using seals for rotating shafts. Hydraulic motors are insensible to moisture and energy may be supplied through pipes and hoses. This affords the further advantage of precluding any transmission of structureborne noise from the drive motor through the energy supply line. If, in addition, the motor is connected to the submarine craft by an arrangement including flexible sound-deadening elements, the transmission of structure-borne noise to the pressure hull can be largely eliminated, which has the advantage that propeller, bearing and motor noise is kept away from the pressure hull so that the pressure hull no longer acts like a resonant cavity which radiates noise toward the inside and the outside.

According to a preferred embodiment of this invention, electric storage batteries are used as energy sources in a manner known per se and the converter comprises an electric motor and a hydraulic pump. The converter may be designed as a totally enclosed unit housing the motor and the pump in its interior, in which case only the two electric feeders for the motor and the two hydraulic lines leading to the pump connectionsare passed through the enclosure. Alternatively, the electric motor driving the hydraulic pump may be replaced by a steam turbine which receives its energy from a nuclear reactor installed in the craft, for example.

However, the hydraulic energy transmission system not only serves to drive the propellers for propulsion and steering of the submarine craft, but, according to a preferred embodiment of this invention, enables a system for fine adjustment of the buoyancy to be connected to it which comprises a tank into which water is admitted orfrom which water is expelled by means of a hydraulic fluid to produce a corresponding change in buoyancy. Such a system is described in the copending application Ser. No. 203,644 now abandoned. lt enables the effective weight of the craft and, thus, its positive or negative buoyancy to be changed. According to a further embodiment of the invention, submarine tools and manipulators located outside the pressure hull may be connected to, and operated by, the hydraulic energy transmission systemfSuch tools may, for instance, include grapplers, scrapers, soil sampling devices and the like with which a submarine craft employed for underwater work and research may be equipped. Preferably, the hydraulic energy transmission system of this invention is adapted for connection of a trim device by means of which heavy masses may be shifted to alter the position of the center of gravity of the craft. Such a trim device is described in the copending application Ser. No. 203,643 now abandoned.

Each propeller and its drive motor may be disposed with spaced relation to each other, connected only by a shaft. According to a preferred embodiment of the invention, each propeller is combined with the associated drive motor into a single structural unit located outside the pressure hull, said structural units being connected to the pressure hull only by means of flexible rubber elements, such as rubber-bonded metal bearings, and through hydraulic hoses. This embodiment affords the advantages of greatly reduced noise and a very compact construction, because even a low-volume hydraulic motor will produce a very high torque owing to the high pressures which it permits.

The invention permits the use of different types of hydraulic motors such as gear motors or vane-type motors. Preferably, however, the motors driving the propellers are of the axial piston type with the housing directly exposed to the water.

The shaft driving the propeller is preferably sealed towards the interior of the motor by means of a sliding ring seal. A leak-water collecting chamber sealed against the outboard water by means of a further sealing arrangement is provided on that side of said sliding ring seal which faces the water. This chamber is connected to a leak-water tank whose internal pressure is maintained at a predetermined value. The internal pressure in this chamber may, for example, equal the atmospheric pressure existing at the water surface and inside the pressure hull. This ensures that on the one hand water leaking past the outer sliding ring seal will be drained without causing damage and that on the other hand the lip seal sealing the interior of the motor will only be subjected to the permissible pressure, since a predetermined pressure is being maintained in the leak-water collecting chamber, so that the said seal may attain the desired useful life.

In preferred embodiments of this invention, a propeller shaft bearing is provided adjacent to the sliding ring seal and accommodated within the same housing as said seal. The advantage consists in that this arrangement results in a very compact construction. Although an overhung mounting of the propeller is possible, a preferred arrangement is one in which that part of the housing which encloses the leak-water collecting chamber is provided with a cylindrical extension carrying a water-lubricated bearing at its end. The propeller inclusive of the motor, if desirable is surrounded by a ring-shaped jacket which orients the stream of water displaced by the propeller and also protects the propeller from damage by foreign matter.

According to preferred embodiments of this invention, flow control valves are provided in the hydraulic supply line of each drive motor to control its speed and- /or sense of rotation. These flow control valves permit a very accurate metering of the flow of hydraulic fluid and, thus, a very sensitive adjustment of the desired speed. Change-over valves which are operated to reverse the sense of rotation are provided upstream or downstream of the flow control valves. The various valves are preferably grouped together in a common housing block.

Further details and developments of the present invention will become apparent from the following description in which one embodiment of this invention will be explained by way of example with reference to the accompanying drawing which shows this embodiment in a highly schematized and simplified representation and in which FIG. 1 is a diagrammatic representation of a submarine craft with a hydraulic energy transmission system in accordance with the invention,

FIG. 2 shows a longitudinal section through a propulsion unit, and

FIG. 3 is a basic circuit diagram of a system in accordance with the invention in which the control valves are represented by symbols.

The submarine craft has a pressure hull 1 shaped like a cylinder with hemispherical end sections. Inside the pressure hull there is provided an energy converter comprising a motor 2 and a pump 3 driven by said motor. The motor 2 is fed by an'energy source 4 which may be located inside or outside the pressure hull 1.

vThe suction end of the pump 3 is connected to a hydraulic fluid tank 5. Through a supply line 6, it delivers hydraulic fluid under high pressure to a control device 7 represented as a block. The control device 7 accommodates a plurality of throttle valves and reversing valves which supply the fluid flow delivered through the supply line 6 to various consumers in accordance with a pattern which may be selected and changed as desired. A return line 8 returns any excess of hydraulic fluid from the control device 7 to the hydraulic fluid tank 5. In the embodiment shown by way of example, the control device 7 distributes hydraulic fluid to three hydraulic motors. One of these motors is part of a propulsion unit producing a thrust acting approximately along the longitudinal axis of the pressure hull 1 while the two other motors produce a horizontal thrust.

Each motor is connected by two lines, one supply line and one return line. The functions of the two lines may be reversed, thereby reversing the sense of rotation of themotor. A flow control or metering valve is provided in one of the two lines or, alternatively, upstream of the point at which the hydraulic fluid stream enters one of the two lines. The flow control or metering valve may also be combined with the control valve by means of which the functions of the two lines may be reversed. All these valves are accommodated in the control device 7. They may be manually controlled or remotecontrolled, e.g. by electric power.

From the control device 7, two lines 9 lead to a hydraulic motor 10 which is disposed outside the pressure hull 1 with a vertically extending shaft. At the end of this shaft there is provided a steering propeller 11. The hydraulic motor 10 is located at the stern of the submarine craft. Similarly, a hydraulic motor 12 is provided outside the pressure hull l in the vicinity of the bow of the craft. This hydraulic motor is connected to the control device 7 by means of two lines 13 through which hydraulic fluid may be supplied and returned. At its free end, the horizontally extending shaft of the hydraulic motor 12 carries a steering propeller 14.

At the stern of the craft, there is provided a hydraulic motor 15 whose output shaft 16 extends parallel to the longitudinal axis of the pressure hull 1 and, at its free end, carries a propeller 17 which propels the craft ahead and astern. The hydraulic motor 15 is connected to the control device 7 by means of two lines 18 through which hydraulic fluid may be supplied and returned. From each of the

motors

10, 12 and 15 a leakwater line 19, 20 and 21 respectively leads to a leakwater collecting tank 22 whose internal pressure equals the internal pressure of the pressure hull l which is always below atmospheric pressure, equalling atmospheric pressure only in the surfaced condition of the craft.

All lines are passed through the pressure hull l in a pressure-tight arrangement. Inside the pressure hull, each line incorporates a shut-off valve 23. Finally, each

hydraulic motor

10, 12, 15 is connected to the hydraulic fluid tank 5 by means of a

leakage line

24, 25 or 26 respectively. These lines return any leakage of hydraulic fluid to the hydraulic fluid tank. Inside the pressure hull, these leakage lines are also provided with shut-off valves 23.

The pressure which the pump 3 generates in the hydraulic system may be adjusted to a desired value by varying the amount of fluid delivered by the pump. If the pump is an axial piston pump oran axial cylinder swashplate pump, its delivery may be varied by adjusting the stroke, or else delivery may be varied by changing the speed at which the pump is driven. However, a preferred arrangement is one in which the pressure generated in the system may be adjusted by means of an overflow valve 27 which opens at a predetermined pressure and allows hydraulic fluid from the supply line 31 to flow into a leakage line 28 which leads to the hydraulic fluid tank, 5, the discharge section to which the overflow valve is opened being such that the desired pressure is maintained in the hydraulic system. When the pressure rises, the discharge section of the valve is increased, when the pressure drops, the discharge section is reduced. Such valves are well known in the art. In their simplest form they feature a piston which is exposed to the fluid pressure and backed by a spring. When the pressure rises, the piston is displaced and the spring compressed. Simultaneously, the piston opens a drain opening through which fluid may flow off. Now, this pressure may be altered from outside by changing the initial compression of the spring. In the present system, the initial compression of the spring may be changed by means of a pilot valve 29 (FIG. 3) provided at the control station of the submarine craft. The pilot valve 29 and the valve 27 are of identical design. The compression spring 30 of the pilot valve can be manually adjusted. This adjustment produces a corresponding adjustment of the pressure existing in a supply line 32 which is connected to the overflow valve 27. The pressure existing in the supply line 32 is applied to that side of the piston in the overflow valve 27 which is exposed to the action of the compression spring so that it assists the action of the spring. The supply line 32 is supplied with hydraulic fluid through a branch line 33 which incorporates a throttle 34. Through a leakage line 35, the hydraulic fluid is returned from the pilot valve 29 to the hydraulic fluid tank 5 shown several times in FIG. 3.

Apart from the overflow valve 27, the control device 7 also comprises the reversing

valves

36, 37 and 38 which in their central position of rest shown in FIG. 3 interrupt the supply of hydraulic fluid to the

drive motors

12, 10 and 15. Depending on the control setting at any time, the respective motor will rotate clockwise or counterclockwise. From each reversing valve, one return line (diagrammatically represented as return line 8 in FIG. 1) leads to the hydraulic fluid tank 5 via

adjustable throttles

39, 40 and 41.

In addition to the

drive motors

10, 12 and 15 for the main and steering propellers, further control and regulating devices may be connected to the hydraulic sysconnected via a non-return valve 42. A throttle 44 which may be connected to a hydraulic bladder accumulator 46 via a reversing valve 45 is connected at the liquid end of the hydraulic accumulator 43. The interior of the bladder accumulator 46 is divided into two separate spaces by means of a flexible partition 47. One of these spaces is connected to the hydraulic system via the reversing valve 45 while the other of these two spaces is connected to the outside through a line 48 which leads into the outboard water. When hydraulic fluid is supplied to the bladder accumulator 46 via the reversing valve 45, water is expelled from the other space of the bladder accumulator 46 so that the weight of the craft is reduced and its positive buoyancy increased. When, conversely, the space of the bladder accumulator 46 filled with hydraulic fluid is connected to the hydraulic fluid tank 5 by a switch-over of the reversing valve 45, the external pressure forces water through the line 48 into the bladder accumulator 46, causing the hydraulic fluid contained in the other space of the bladder accumulator 46 to flow into the hydraulic fluid tank 5. This inflow of water increases the weight of the craft and reduces its positive buoyancy. By means of this arrangement, the buoyancy of the craft may be adjusted within very fine limits.

In a submarine craft, the center of gravity may be shifted, e.g. when one of the crew changes his position inside the craft. This would cause the craft to deviate from its desired horizontal or almost horizontal position. To compensate such deviation, a trim device is provided by means of which weights are shifted so as to restore the desired trim, i.e. the desired position of the craft with respect to the horizontal. To this end, a manual change-over valve 50, which takes the form of a three-way valve, is connected to the hydraulic energy supply system via a supply line 49. In one position, the said manual change-over valve connects the supply line 49 with a reversing valve 51 which has a central position of rest and two control positions. In the position of rest, the flow is shut off. In the one control position, hydraulic fluid flows to a power cylinder 53 through the reversing valve 51 and a control line 52. In the power cylinder 53 there is provided a slidable piston 54 which moves relatively to the said cylinder and, through a compensating line 55, admits hydraulic fluid to a fur- 'ther power cylinder 56 in which a piston 57 is slidably guided which, when moved, forces hydraulic fluid to the hydraulic fluid tank 5 via a leakage line 58, the reversing valve 51 and a further line 59 with an active, adjustable throttle 60. When the reversing valve 51 is moved to its other control position, hydraulic fluid from the supply line 49 flows to line 58 via the manual change-over valve 50 and through the reversing valve 51 and hydraulic fluid from the power cylinder 53 flows through line 52 to line 59 and on to the hydraulic fluid tank 5. In this case, the two

pistons

54 and 57 are moved in opposite directions. The pistons are coupled to heavy masses which may thus be moved in opposite directions to adjust the desired trim. The manual changeover valve 50 may have connected to it a hand pump 61 which enables the trim device to be operated manually in the event of a failure of the hydraulic energy supply system by manually pumping hydraulic fluid to the reversing valve 51.

To prevent mechanical impurities of the hydraulic fluid from entering the hydraulic energy supply system, a filter 62, which cleans the hydraulic fluid sucked from the hydraulic fluid tank 5, is disposed upstream of the pump 3.

FiG. 2 shows a longitudinal section through a propulsion unit. Each propulsion unit comprises a fixed hub section 63 in the form of a hollow cylinder with three integrally cast fins 64 spaced at angles of l20each. By the fins 64 the propulsion units may be fastened to the submarine craft, sound-deadening flexible elements being interposed between the fins and the hull. Each fin and the associated flexible elements are provided with four

bores

65, 66, 67 and 68. The hydraulic bores 65 and 66 serve to supply and return hydraulic fluid to and from the hydraulic motor 10 which is accommodated within the hub section 63. The leak-water bore 67 serves to drain any leak water entering the unit while the leakage bore 68 drains any hydraulic fluid leaking from the hydraulic motor 10.

The output shaft 69 of the hydraulic motor 10 is coupled to an intermediate shaft 70 in a manner preventing relative rotation. The intermediate shaft 70 is supported in a ball bearing 71 fitted in a bearing sleeve 72 provided in the bearing sleeve 72 which ends in an annular space 77 surrounding a central portion of the intermediate shaft 70. Between the annular space 77 and the ball bearing 71 there are provided two sliding sealing rings 78 which seal the annular space 77 with respect to the ball bearing 71. A slide ring 79 on the intermediate shaft 70 serves as an axial backing for a support ring 80 which, in turn, has a shoulder forcing an O-ring 81 against a shoulder 82 of the bearing sleeve 72. The O-ring 81 provides a tight seal for the annular space 77 towards the outside. Water which leaks past the slide ring 79 enters the annular space 77 whence it flows, without pressure, to the leak-water collecting tank 22 through the leak-water bore 76, the leak-water bore 67 and the leak-water line 19. A bearing cap 83, which is provided with bores and forms a waterlubricated plastic bearing for the propeller shaft, is screwed to the end of the bearing sleeve 72. The bores provided in the bearing cap 83 as well as the bearing sleeve 72 ensure adequate cooling of the slide ring seal 79 by means of circulating water. The hemispherical end cap of a hollow hub 84 to which the blades of the propeller 11 are secured, e.g. as integral castings, is screwed to the free end of the intermediate shaft 70.

It shall be understood that the present invention is not restricted to the embodiment shown by way of example and that deviations therefrom are possible within the scope and spirit of the invention. In particular, it shall be understood that individual features of this invention may be employed either severally or in combination.

One advantage of the propulsion system in accordance with this invention consists in that a leak-water collecting chamber is disposed downstream of the shaft seal which seals the system off from the high external pressure, whereby the seal towards the interior of the motor is totally or largely relieved of pressure. In case of damage to the pressure-loaded shaft seal, the entry of leak water from the leak-water collecting chamber into the pressure hull may readily be prevented by closing the relevant shut-off valve 23 in line 19, 20 or 21.

What is claimed is:

l. A submarine craft comprising: a tight pressure hull, an electric energy source, a plurality of propellers, each of said propellers being provided with a drive shaft, hydraulic motor means for driving each of said propellers, a hydraulic energy transmission system in cluding converter means operatively connected with said electric energy source for converting said electric energy to hydraulic energy, means operatively connected with said converter means for supplying hydrau: lic energy to said hydraulic motor means. said hydraulic motor means including an axial piston motor for driving each of saidplurality of propellers, a housing surrounding each of said motors, the surface of said housing being in direct heat contact with the water flowing therearound, each of said propellers and each of said motors being combined into a single structural unit disposed outside of said pressure hull, means for sealing each of said drive shafts toward the interior of said motor, a sliding ring seal, a leak-water collecting chamber provided on a side of said ring seal which faces the water, and a leak-water tank operatively connected to said leak-water collecting ch trnbegsaid leakwater tank having an inter'nal pressure which is always less than the pressure permitted for said sliding ring seal.

2. A submarine craft as claimed in claim 1, wherein said electric energy source includes electric storage batteries and wherein said converter comprises an electric motor and a hydraulic pump.

3. A submarine craft as claimed in claim 1, further comprising a trim means operatively connected with said transmission system for changing the center of gravity of the craft.

4. A submarine craft as claimed in claim 1, further comprising a buoyancy means operatively connected with said hydraulic energy transmission system for fine adjustment of the buoyancy of the craft, said buoyancy means comprising a vessel means for admitting water into said vessel to change the buoyancy and means for admitting hydraulic fluid into said vessel for expelling water from said vessel.

5. A submarine craft as claimed in claim l,-wherein a propeller shaft bearing is provided adjacent to the sliding ring seal and accommodated in said housing.

6. A submarine craft as claimed in claim 1, wherein at least one of flow control valves or chage-over valves are provided to control at least one 'of the speed or sense of rotation of said hydraulic axial piston motors, said valves being operatively connected with a respective hydraulic axial piston motor.

7. A submarine craft according to claim 1, wherein a mounting means is provided for mounting said hydraulic motor means exteriorly of said pressure hull and wherein said mounting means constitute said housing with a portion of said axial piston motor disposed therein.

Claims

1. A submarine craft comprising: a tight pressure hull, an electric energy source, a plurality of propellers, each of said propellers being provided with a drive shaft, hydraulic motor means for driving each of said propellers, a hydraulic energy transmission system including converter means operatively connected with said electric energy source for converting said electric energy to hydraulic energy, means operatively connected with said converter means for supplying hydraulic energy to said hydraulic motor means, said hydraulic motor means including an axial piston motor for driving each of said plurality of propellers, a housing surrounding each of said motors, the surface of said housing being in direct heat contact with the water flowing therearound, each of said propellers and each of said motors being combined into a single structural unit disposed outside of said pressure hull, means for sealing each of said drive shafts toward the interior of said motor, a sliding ring seal, a leak-water collecting chamber provided on a side of said ring seal which faces the water, and a leak-water tank operatively connected to said leak-water collecting changer, said leak-water tank having an internal pressure which is always less than the pressure permitted for said sliding ring seal.

5. A submarine craft as claimed in claim 1, wherein a propeller shaft bearing is provided adjacent to the sliding ring seal and accommodated in said housing.

6. A submarine craft as claimed in claim 1, wherein at least one of flow control valves or chage-over valves are provided to control at least one of the speed or sense of rotation of said hydraulic axial piston motors, said valves being operatively connected with a respective hydraulic axial piston motor.