Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
  • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
  • F01L1/32—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for rotating lift valves, e.g. to diminish wear
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
  • F01L9/00—Valve-gear or valve arrangements actuated non-mechanically
  • F01L9/10—Valve-gear or valve arrangements actuated non-mechanically by fluid means, e.g. hydraulic

Definitions

• Valve turning device for exhaust valves in particular of marine diesel engines
• the invention relates to a valve rotating device for exhaust valves, in particular of marine diesel engines or the like. which is supported in a valve housing for the valve stem between an upper and a lower drive element, wherein it is connected to the lower drive element via a freewheel device which allows the valve stem to rotate during its closing movement, and in relation to the upper one Drive element is supported via a rotary cylinder which, in engagement with a fixed support cylinder, causes the valve spindle to rotate.
• Such a valve rotating device is described in German Patent 3113944.
• the known device comprises two concentrically arranged cylinder sections between which balls are rotatably guided in such a way that they each engage in a spherical shell of one cylinder section and in a spherical groove of the other cylinder section which runs obliquely to the cylinder axis.
• a more even distribution of forces between the two cylinder sections is achieved in that several spherical shells or ball grooves are provided distributed over the circumference of the two cylinder sections.
• the ball grooves preferably run in a spiral with a constant slope.
• a cylinder section is rotated in that the ball guided in the spherical shell runs in the ball groove of the other cylinder section, one of the cylinder sections cuts is blocked by the freewheel device.
• the valve spindle is closed, the cylinder section that is blocked when it is opened is taken in the direction of rotation.
• the present invention has for its object to provide a particularly durable, heavy duty, yet responsive with high acceleration valve turning device of the type mentioned.
• the valve rotating device is basically suitable for all slow-running marine engines, but especially for two-stroke engines in which the upper drive element is formed by a hydraulic cylinder for controlling the opening stroke of the valve and the lower drive element is formed by the piston of a compressed air cylinder for controlling the closing movement of the valve.
• the spring plates of the earlier type, between which the valve rotating device was supported are replaced by a hydraulic cylinder, which forms the upper end of the valve housing, and whose oil piston moves the valve spindle in the direction of its opening so that it lifts off the valve seat, and by an in the opposite direction effective compressed air cylinder, which moves the valve spindle after compression by means of its compressed air piston in the closed position.
• An air pressure of approx. 7 bar is sufficient for this, while the oil pressure acting on the oil piston is up to 170 bar.
• the support cylinder has an internal helical toothing, which in the axial direction at least the length of the opening stroke of the valve plus. corresponds to the minimum engagement length of the two cylinders.
• the rotary cylinder has an external toothing which corresponds in the axial direction at least to the minimum engagement length of the two cylinders.
• Suitable gearing data are required for the helical gearing, e.g. a tooth height of approx. 3 to 5 mm with a pitch of less than 45 °.
• the support cylinder preferably has a toothing that is continuous over its entire length, while the rotary cylinder has an external toothing that extends downward only about a third of its length from its upper end in the installed position, results in lower manufacturing costs for the rotary cylinder; the remaining ring gap between the two cylinders can be used more effectively for oil lubrication.
• the supporting cylinder is expediently secured by shrinking its outer circumference in a corresponding seat of the hydraulic cylinder.
• an annular lubrication groove can advantageously be provided on the outside of the support cylinder, which lubrication oil supplies the toothing via radial bores.
• the rotating cylinder is mounted with its inner circumference via an axial bearing within a cylindrical recess of the piston of the compressed air cylinder, the shaft of the valve spindle being received in a frictional manner in a central through bore of a hub of the piston.
• the rotary cylinder is therefore axially immovable with the piston, but is rotatably supported relative to it in a direction of rotation permitted by the freewheel device.
• the stem of the valve spindle is wedged in the through bore by means of a clamping part and that the clamping part is designed as a conical sleeve which is axially secured by a pressure ring which is screwed to the hub of the piston.
• Conical ring segments preferably made of steel according to SAE 1010, are suitable as the clamping part, which, as described in US Pat. No. 3,938,484, engage with an inner bead in a corresponding annular groove in the stem of the valve spindle.
• the compression of the clamping part by means of the pressure ring is such that the stem of the valve spindle is released in the manner of a slipping clutch at a certain torque, ie it can spin before other components of the valve turning device would be destroyed, for example on the side of the freewheel device.
• a ratchet disk of the freewheel device is fastened on the hub of the piston of the compressed air cylinder, in the circumferential toothing of which engage several ratchet elements which are distributed over the circumference in recesses of the rotary cylinder, where they are each spring-loaded supported.
• a ring-shaped projection of the ratchet ring expediently serves to axially support the axial bearing, which preferably consists of a double deep groove ball bearing. Because the ratchet disc is arranged between the pressure ring and the hub, there is the possibility of screw fastening the pressure ring through bores in the ratchet disc in the hub of the piston.
• the hydraulic cylinder and the compressed air cylinder are separated from one another by the piston of the compressed air cylinder.
• the compressed air cushion which causes the valve to spring back into the closed position;
• the flowing hydraulic oil collects, which is also effective as a lubricating oil.
• the rotary cylinder has a plurality of radial bores distributed over its circumference above the freewheel device and that annular gaps between the two cylinders, and for the hydraulic oil flowing out as a result are provided between the support cylinder and the recess of the piston. From there, the hydraulic oil flowing out then passes through an annular gap delimited by the outer circumference of the compressed air cylinder through further radial bores in the valve housing and back into the oil sump or an oil reservoir.
• the valve rotating device is arranged between an upper and a lower drive element, wherein both drive elements, namely the hydraulic cylinder and the compressed air cylinder, act on the stem of the valve spindle via their respective pistons.
• the axial movement results in the rotation of the rotating cylinder, corresponding to the helical toothing of both cylinders.
• the opening stroke of the valve spindle results in a rotary movement of the rotating cylinder in a direction of rotation released by the filing device when the spindle movement is straight.
• the closing movement of the valve spindle when the hydraulic cylinder is depressurized results in a rotation of the rotary cylinder with the opposite direction of rotation under the action of the compressed air cushion, i.e.
• the ratchet elements of the freewheel device drive the ratchet disc, via which the rotary movement is transmitted to the valve spindle.
• This rotary movement of the valve spindle is used to grind the valve plate onto the valve seat on the housing side when the two seat surfaces meet.
• the grinding movement ends with increasing pressure when the seat is reached, a short overrun phase corresponding to the mass torque of the valve spindle being possible in that the freewheel device allows the ratchet disk to rotate.
• the valve rotating device according to the invention is not only suitable for installation on new engines; it is also suitable for retrofitting in the respective valve housing by machining the hydraulic cylinder, in particular by providing it with the support cylinder and by giving the compressed air cylinder a new piston on which the remaining parts of the valve rotating device are built.
• valve rotating device With the valve rotating device according to the invention it is possible to considerably extend the service life of the valve spindles between two overhauls, for example for two-stroke engines from 6,000 hours so far to approximately 18,000 hours. This is brought about by the high rotational energy that can be achieved by means of the valve rotating device according to the invention when the valve disc is ground in on the valve seat on the housing, a defined rotational energy having an effect when the seat position is reached. This achieves the desired polishing effect, by means of which deposits in the area of the valve seat surfaces are removed, combined with the advantage that this results in an improved heat transfer between the bare metal valve seat surfaces, which advantageously results in a lower temperature in the area of the valve cone seat.
• FIG. 1 shows a cut-away spatial representation of a valve housing
• FIG. 2 the upper part of the valve housing with the hydraulic cylinder cut open
• FIG. 3 shows detail III according to FIG. 1 in an enlarged representation
• FIG. 4 shows a section according to IV-IV of FIG. 1, also in an enlarged view
• Figure 5 is a cut spatial representation of the piston of the air cylinder
• FIG. 6 shows a section according to VI-VI of FIG. 5.
• FIG. 1 shows the valve housing of a two-stroke diesel engine for a ship propulsion system with a valve spindle 1 installed therein in its closed position.
• a compressed air cylinder 5 sits on a valve housing 2, in which the stem 3 of the valve spindle 1 is rotatably mounted within a bearing bush 4, and a hydraulic cylinder 6 sits thereon.
• the latter is shown separately in the same sectional view in FIG. 2.
• a valve seat ring 7 on the housing side is inserted and fastened there by means of screws 8.
• the valve seat ring 7 forms with its open end the valve seat surface on the housing side, which by a pretreated, for. B. hardened or welded as hardening alloy material section 9 and which cooperates with a corresponding valve seat surface 10 (valve cone seat) on the top of the valve plate 11.
• a support cylinder 13 is fastened with its outer peripheral surface by shrinking.
• the support cylinder 13 has on its inner circumferential surface a helical toothing 14 with which a rotary cylinder 15 is engaged, which has on its outer circumferential surface an outer toothing 16 corresponding to the inner toothing 14 of the support cylinder 13.
• the rotary cylinder 15, which in Figure 5 is shown enlarged, is rotatably received in a recess 17 of the compressed air piston 18, which is accommodated within the compressed air cylinder 5 in a sealing and axially displaceable manner.
• the compressed air piston 18 separates the compressed air side with the cylinder space 19 for the compressed air cushion from an outflow chamber 20 for the hydraulic oil, which also serves as a lubricating oil.
• a hydraulic piston 21 is drawn, which is supplied with hydraulic oil via an oil pressure line 22.
• the stroke of the hydraulic piston 21 in the direction of the opening movement of the valve spindle 1 is limited by the outflow channels 23 which open into the outflow chamber 20 for the hydraulic oil.
• the hydraulic piston 21 overlaps the upper end 24 of the valve stem 3 in a bell-shaped manner in order to move it downward in the opening direction of the valve spindle when the oil pressure is up to 170 bar.
• the cylinder chamber 19 of the compressed air cylinder 5 is connected to the compressed air supply of the operating system with 5 -
• valve spindle 1 Due to the compressed air cushion in the cylinder chamber 19, the valve spindle 1 is moved back into the closed position as soon as it has reached the bottom dead center (not shown) at the maximum open position and the oil pressure in the hydraulic cylinder 6 is relaxed accordingly.
• the pressure oil will during its outflow, forced to flow from the outflow lines 23 through an inner region 25 of the outflow chamber 20 and through various bores and annular spaces, as will be described in more detail below in connection with FIG. 3, into an outer region 26 of the outflow chamber 20 of the hydraulic cylinder 6 and from there Via an annular space 27 between hydraulic cylinder 6 and compressed air cylinder 5 and further through radial bores 28 in hydraulic cylinder 6 back into the oil container.
• FIG. 3 shows detail III of FIG. 1 in an enlarged representation.
• the hydraulic cylinder 6 with the support cylinder 13 fastened therein can be seen, with the internal toothing 14 of which engages with an external toothing 16 of the rotary cylinder 15.
• the external toothing 16 is substantially shorter in the axial direction than the internal toothing of the support cylinder 13. In this way, the two cylinders remain in constant engagement with one another during the opening stroke of the valve spindle 1.
• the helical toothing 14, 16 is sufficiently lubricated by the hydraulic oil flowing out;
• a circumferential lubrication groove 29 can be provided for lubrication of the threaded connection, which is connected via radial bores 30 through the support cylinder 13 to its internal toothing 14.
• the lubrication groove 29 is supplied with lubricating oil via an oil connection 31.
• a minimum engagement length is sufficient for the threaded connection, so that the external toothing 16 of the rotary cylinder 15 has only about half to one third of the axial length of the internal toothing 14 of the support cylinder 13.
• the support of the rotary cylinder 15 within the recess 17 of the compressed air piston 18 is carried out by an axial bearing, which consists of an axial ball bearing 35. Its axial support is also served by a lower support ring 36, which springs into a corresponding groove on the inside of the rotary cylinder 15, and a collar 37 of a ratchet disk 38 of a freewheel device.
• the ratchet disk 38 is fastened on a hub 39 of the air pressure cylinder 18 by means of screws 40.
• the ratchet disk 38 can be seen, which is covered at the top by a pressure ring 44, which is also screwed onto the hub 39 of the compressed air cylinder 18 by means of screws 45. Accordingly, the ratchet disc 38 has bores 46 through which the screws 45 are screwed in. In the illustration according to FIG. 6, these holes 46 are for inserting the screws 45 in the ratchet disk 38 drawn. The screws 40 still present there are used to fasten the ratchet disk 38.
• FIG. 6 which shows a section according to VI-VI of FIG. 5, one can see in the horizontal section the rotary cylinder 15 in which six ratchet elements 41 are mounted distributed over the circumference.
• Each of these ratchet elements 41 is held in its locked position by a pawl 43 loaded with a ratchet spring 42.
• This locking position prevents rotation of the ratchet disc 38 relative to the rotary cylinder 15 in a direction of rotation according to arrow Pl.
• the ratchet disk 38 can be rotated with respect to the rotary cylinder 15 in an opposite direction of rotation according to arrow P2. In such a case, the pawls of the ratchet elements 41 slide over the teeth of the ratchet disk 38.
• FIG. 5 The enlarged sectional view according to FIG. 5 serves to clarify the arrangement of the rotary cylinder 15 within the recess 17 of the compressed air piston 18.
• the support cylinder 13 is omitted.
• the center bore in the compressed air cylinder 18, which ends conically at the top, can be seen particularly clearly.
• a clamping part is wedged in the form of a conical sleeve 48, which is axially secured by the pressure ring 44.
• the cone sleeve 48 has on its inside near its upper edge an inwardly projecting bead 49 which engages in a corresponding annular groove 50 of the stem 3 of the valve spindle 1. If the valve spindle 1 is moved downwards in the direction of the valve opening by supplying pressure oil via the oil pressure line 22 from the closed position shown in FIG. 1, in which the hydraulic piston 21 exerts a corresponding force on the upper end 24 of the valve stem 3, this axial stroke movement causes an corresponding axial adjustment of the rotary cylinder 15, which rotates with support relative to the support cylinder 13 in the direction of arrow P3 ( Figure 4), while the valve tappet is moved straight down so that the valve seat opens.
• valve spindle 1 When the valve seat is reached, causes the valve plate 11 to be ground in against the valve seat on the housing, the seat surfaces grinding each other in the desired manner.
• the valve seat surfaces on both sides forming the valve seat are polished smooth so that a tight valve seat is achieved and also the heat exchange between the valve plate 11 and the valve seat ring on the housing side is improved.
• the direction of rotation of the valve disk indicated in FIG. 4 according to arrow P5 during grinding corresponds to the direction of rotation of the ratchet disc according to arrow P4.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Valve-Gear Or Valve Arrangements (AREA)
• Valve Device For Special Equipments (AREA)
• Actuator (AREA)

Applications Claiming Priority (1)

Publications (1)

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ID=34957390

Family Applications (1)

Country Status (6)

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• 2004
  • 2004-04-27 US US11/587,508 patent/US7707982B2/en not_active Expired - Fee Related
  • 2004-04-27 CN CN2004800428926A patent/CN1961137B/zh not_active Expired - Fee Related
  • 2004-04-27 JP JP2007509880A patent/JP4778506B2/ja not_active Expired - Fee Related
  • 2004-04-27 EP EP04729638A patent/EP1642010A1/de not_active Withdrawn
  • 2004-04-27 WO PCT/EP2004/004437 patent/WO2005116408A1/de active Application Filing
• 2007
  • 2007-07-06 HK HK07107241.5A patent/HK1102615A1/xx not_active IP Right Cessation

Non-Patent Citations (1)

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