KR20190057375A - How to install a hub cap on a ship's propeller and hub - Google Patents

Abstract

The present invention relates to a novel propeller for a marine vessel and a method for installing a hub cap on the hub. In particular, the present invention relates to hub caps for use in connection with fixed pitch and controllable pitch propellers.
The propeller of the present invention comprises a hub having a hub body 42, propeller blades and hub cap 66, said hub cap 66 having an outer surface provided with fins, Is fastened to the rear end of the hub body (42).

Description

How to install a hub cap on a ship's propeller and hub

The present invention relates to a novel propeller for a marine vessel and a method for installing a hub cap on the hub. More particularly, the present invention relates to hub caps for use in connection with fixed pitch and controllable pitch propellers.

The propulsion unit of the ship generally comprises a hub and propeller blades arranged in the hub. The hub includes drive means, which may be, for example, a drive shaft, an angle gear, a transmission or an electric or hydraulic drive. The propeller may be a so-called fixed pitch propeller (FPP) or a controllable pitch propeller (CPP). The former having blades fastened to the annular hub body and the latter having blades arranged as control means for controlling the pitch of the blades and said control means being located in the hub of the propulsion unit.

The control means for controlling the pitch of the propeller blades includes an actual mechanical rotary arrangement arranged in the hub and actuating means for actuating the mechanical rotary arrangement. The mechanical rotating arrangement includes a crank ring for each propeller blade.

There are basically two types of operating means, namely mechanical operating means and hydraulic operating means. The mechanical actuation means includes a rod extending along the central bore at the drive shaft from the drive means into the interior of the hub. With respect to the hydraulic actuation means, the movable member within the hub is arranged to act as a piston in the hydraulic cylinder.

The problem with the propellers is the relatively large diameter at which the roots of the propeller blades are arranged. As the diameter of the hub increases, the flow through the propeller blades must fill the open cavity downstream of the hub, so that the propeller hub forms a hydrodynamically inefficient one. In other words, a hub terminating in a substantially radial surface with a diameter corresponding to the hub diameter creates a reduced pressure area downstream of the hub, which in effect means creating a force in the direction opposite to the thrust of the propeller That is, to reduce the net thrust of the propeller. A so-called hub vortex is created while the water fills the opening cavity. The hub swirls appear in a more intense form when the swirls begin cavitation, i.e., when the swirls form gas bubbles in the swirl. The real problem with the hub vortex is that it significantly reduces the propeller's available thrust. Naturally, this problem may be manifested at a larger scale in the controllable pitch propellers due to the larger hub diameter.

A problem associated with the hub vortex has been attempted to be solved by arranging the hub cap on the downstream end of the hub and the pins on the hub cap and causing both the hub cap and the pins to rotate with the propeller. With this arrangement, propeller thrust is increased or fuel consumption is reduced by an average of 2 to 3%. The hub cap may be a cylindrical extension of the hub, but is generally a convergent extension. The convergence may be conical or curved.

If the propeller is of a fixed pitch type or sometimes controllable pitch type, the hub cap may be easily fastened from its interior to the end of the hub, as discussed in co-pending patent application PCT / EP2016 / 058311. However, if the propeller is a controllable pitch propeller having a hydraulic operating means with a hydraulic cylinder arranged at the aft end of the propeller hub, i.e. at the opposite end of the drive or the forward end of the hub, As an integral part or as a separate part attached to the rear end of the hub, a further problem may arise. Since the hub radius at the roots of the blades is clearly larger than the outer radius of the hydraulic cylinder, the hub cap is preferably arranged to cover the radial difference by a generally streamlined surface that converges back from the hub's maximum diameter . Although it is hydrodynamically efficient to bring the hub cap very close to the outer surface or end of the hydraulic cylinder, there is no room for fastening the hub cap therein, so that the fastening must be arranged outside the hub cap. The same problem may also appear in controllable pitch propellers with mechanical actuation means. In other words, the hub body has an axial extension at the aft end, the diameter of which is smaller than the diameter of the rest of the hub body, and the axial extension fills the interior of the hub cap.

According to an exemplary prior art configuration (e.g., see FIG. 1), the hub cap is formed with a converging section provided with fins on its outer surface. The converging section of the hub cap has an inwardly extending flange at the end of the converging section of the hub cap facing the aft end of the hub, provided with holes for bolts or screws used to fasten the hub cap to the hub. Therefore, fastening of the hub cap is easy to perform inside the hub cap. However, if the interior of the hub cap is somewhat filled with the axial extension of the hub body, fastening of the hub cap in the interior is not possible.

Accordingly, an object of the present invention is to design a novel hub cap having a simple construction that is low in manufacturing cost.

Another object of the present invention is to design a novel hub cap having a lightweight construction and easy to install.

It is a further object of the present invention to design a novel hub cap that may be fastened from the exterior of the hub cap to the rear end of the hub.

It is another object of the present invention to provide a possibility to provide a modern hub cap to existing propellers.

At least one of the objects of the present invention is substantially satisfied by a marine propeller, wherein the propeller includes a hub having a hub body, propeller blades, and a hub cap attached to the rear end of the hub body, Has an outer surface provided with fins and the hub cap is fastened to the hub body by a separate circular connection ring coaxial with the hub body.

At least one of the objects of the present invention is substantially satisfied by a method of installing a hub cap at a rear end of a hub of a propeller, said propeller comprising a hub having a hub body, propeller blades and a hub cap, The cap has an outer surface provided with fins and an inner surface having an inner diameter, the method comprising the steps of:

a) fabricating a circular connecting ring to have an outer diameter equal to the inner diameter of the hub cap,

b) providing radial through holes in the hub cap,

c) providing radially extending blind holes in said connecting ring,

d) providing the connecting ring with axial through holes,

e) providing threaded holes in connection with the hub body,

f) fastening the connecting ring to the rear end of the hub body by bolts screwed into the threaded holes,

g) attaching the hub cap to the connecting ring, and

h) Pressing the dowels into the holes to fasten the hub cap to the circular connecting ring.

Other characteristic features of the invention may be seen in the appended claims.

The present invention provides among other things the following advantages:

· Simple and affordable configuration,

A lightweight configuration that is easier to install, and

Easy installation due to easy separate installation steps.

In the following, the present invention will be described with reference to the accompanying exemplary and schematic drawings.

1 illustrates an axial cross-sectional view of a hub of a propulsion unit of a prior art ship,
Figure 2a illustrates an axial cross-sectional view of a hub of a propeller of a ship in accordance with a first preferred embodiment of the present invention,
Figure 2b illustrates an enlarged partial view of the hub of Figure 2a,
Figure 3A illustrates an axial cross-sectional view of a hub of a propeller of a ship in accordance with a second preferred embodiment of the present invention,
Figure 3b illustrates an enlarged partial view of the hub of Figure 3a.

1 illustrates an axial cross-sectional view of a hub 10 of a controllable pitch propeller of a prior art ship. In the following description, the term "aft" refers to an element or part of an element that points or points to the aft end or stern of a vessel, and "forward" refers to a forward or ending point of a vessel, Quot; and " forward " are used to refer to parts of the elements. The hub 10 includes a hub body 12, a trailing end cover 14 at the trailing end of the hub body 12, a front end cover 16 at the front end of the hub body 12, 18, crank rings 20, propeller blades 22, and hub cap 24. The front end cover 16 at the front end of the hub body 12 has an opening for receiving a drive shaft extending into the cylindrical opening 26 at the center of the cylinder yoke 18. [ A drive shaft (not shown) is provided with a flange that is bolted to the threaded holes 28 at the front end of the hub body 12 to rotate the hub body 12. The drive shaft is provided with means for being fastened to the opening 30 of the cylinder yoke 18 to move the cylinder yoke 18 in the axial direction. The cylinder yoke cooperates with the crank rings 20 to control the pitch of the propeller blades 22 while the cylinder yoke 18 is moved in the axial direction. The rear end cover 14 is fastened to the rear end of the hub body 12 by bolts 32.

The hub cap 24 of the prior art hub 10 is formed as a converging section 34 on the outer surface to which the fins 36 are fastened, between the forward and aft axial ends of the hub cap. The converging section 34 of the hub cap 24 is provided with a flange 38 extending radially inward along its rear end cover 14 at its front end and fastened thereon by bolts or screws 40, Is provided.

Since the inside of the hub cap is opened at the rear end, fastening of the hub cap to the rear end of the hub body is easy. However, as already discussed above, when the interior of the hub cap is filled with hydraulic components for controlling the pitch of the hub components, for example, the propeller, the distance between the hub cap and the hub body or hub The interface between the rear end cover is not accessible, and therefore the fastening of the hub cap must be performed in a slightly different manner from the outside of the hub cap. Thus, in order to fasten the hub cap to the rear end of the hub body or the rear end cover of the hub, the following two embodiments are proposed.

Figs. 2A and 2B schematically illustrate an axial cross section of a hub according to a first preferred embodiment of the present invention. Fig. The hub 40 includes a hub body 42 which is fastened to a flange 44 arranged at the end of the drive shaft 46, for example. The hub is connected to a plurality of propeller blades (not shown) rotatably arranged by attaching each blade 48 to its own rotatable crank ring 52, preferably by bolts, through a blade foot 50, (48). The blade foot 50 and / or the crank ring 52 are sealed to the hub body 42 to prevent oil that is used to lubricate the interior of the hub, i.e., the mechanical pitch control means, from leaking into the water surrounding the hub during operation.

Inside the hub 40, there is provided a means for controlling the pitch or changing the blade angle of the propeller, i.e., for changing the blade angle position between the ahead and astern positions as already mentioned in connection with FIG. Hydraulic means is provided. At the opposite end of the drive shaft 46 the hub 40 is provided with an axial extension extending through the flange 56 extending radially to the aft end of the hub body 42, Is provided. Inside the aft end cover 54 there is provided a piston 58 which divides the cylindrical internal volume of the aft end cover 54 into two chambers: a rear oil chamber 60 and a front oil chamber 62 . The piston 58 is fastened to the end of the cylinder yoke 64 so that movement of the piston 58 rotates the crank rings 52 and the crank rings change the pitch of the propeller blades 48 in some of them . 2a also shows a hub cap 66 with fins 68 which is fastened to the hub body 42 by means of fastening means 70. Fig.

Fig. 2b shows an enlarged view of detail A of Fig. 2a, i.e., fastening means 70. Fig. The bolts 76 for fastening the rear end cover 54 to the hub body 42 are used to fasten the hub cap 66 to the hub body 42. [ The fastening means 70 comprises a circular connection ring (not shown) coaxially attached to the hub body 42 by stud bolts 74 screwed into the blind screw holes 78 in the axial direction of the heads of the bolts 76 72). The outer diameter of the circular connecting ring 72 is the same as the inner diameter of the hub cap 66 and the circular connecting ring has a function of the radial direction suitable for its function to support the hub cap at the rear end of the hub body Width and axial thickness. Instead of stud-free stud bolts, normal bolts (e.g., bolts with hex head) may also be used. The distance rings 80 are only engaged with the stud bolts 74 and the connecting rings 80 for the support of the distance rings 80. In the case where the heads of the bolts 76 are arranged below the trailing end surface of the trailing end cover 54, Is used to raise the position of the arm 72. The connecting ring 72 is pressed against the heads of the bolts 76 and the distance rings 80 by the locking rings 82 and nuts 84 threaded to the stud bolts 74. The connecting ring 72 has radial holes 86 extending from the outer periphery of the connecting ring 72 toward the inner periphery, preferably, but not necessarily, blind holes. The hub cap 66 is provided with through holes 88 arranged such that the axes coincide with the axes of the holes 86 of the connecting ring 72. In other words, the distances of the axes of the holes 86, 88 from the rear end surface of the hub body 42 are the same and the distance between the axes of the holes 86, 88 in the circumference of the connecting ring 72 and hub cap 66 The numbers and positions are the same. The hub cap 66 is attached to the connecting ring 72 by dowels 90 pressed into the holes 88, 86. The hole 88 in the hub cap 66 is provided with a threaded section 92 for the threaded plug 94 that is screwed into the threaded section 92 of the hole 88. The screw plug 94 is necessary to prevent dowels from escaping through the holes due to centrifugal forces acting on the dowels when the propeller is actuated.

When preparing to install the hub cap 66 at the rear end of the hub body 42, some or all of the bolts 76 may be fastened with bolts 74, preferably, but not necessarily, Blind screw holes 78 are provided. The connecting ring 72 having an outer diameter corresponding to the inner diameter of the hub cap 66 and a radial dimension extending to cover the bolts 76 is the same as the blind holes 78 of the bolts 76 (Equal number of holes having the same spacing on the same circumference) are provided. The connecting ring 72 is also preferably but not necessarily provided with radial holes 86 in the same drilling step as the radial holes 88 of the hub cap 66.

Figure 3A schematically illustrates a hub 40 'and hub cap 42' according to a second preferred embodiment of the present invention. Here, the basic configuration of the hub is substantially the same as that in the first embodiment discussed in Figs. 2A and 2B with respect to the present invention. Indeed, although the hub body of this embodiment does not have an axial extension as a separate tail end cover, since the hub body, i.e., a portion of the hub including the hydraulic cylinder, is an integral part of the hub body 42 ' The only difference from the perspective of the hub body 42 '. In any case, the hub cap 66 'is fastened to the rear end of the hub body by fastening means 70', shown in detail B in the enlarged illustration of FIG. 3b.

When preparing for installation of the hub cap 66 'at the aft end of the hub body 42' of FIG. 3a, the connecting ring 72 'has its outer diameter corresponding to the inner diameter of the hub cap 66' , And the connecting ring is made to have a sufficient thickness both in the radial direction and in the axial direction. The connecting rings 72 'are then preferably provided with a desired number of axial through holes 96' arranged at equal intervals, for example, but not necessarily, with the same radii from the axis of the connecting ring Twenty holes spaced 18 degrees apart are provided. The distance ring 72 'is then provided with radial blind holes 84' on its outer periphery. Again, the blind holes 86 'are equally spaced in the distance ring 72', but not necessarily. The connecting ring 72 'then communicates with the hub body 42' and is used as a perforation template. The connecting ring 72 'is provided with at least three specific aligning tools for centering the connecting ring 72' relative to the hub body 42 ', and the axial blind holes 78' Is drilled into the body 42 'so that the holes 96' of the connecting ring 72 'and the holes 78' of the hub body are matched to each other. And finally, the blind holes 78 'of the hub body 42' are threaded.

To initiate the installation of the hub cap 66 ', the connecting ring 72' is fastened to the hub body 42 'by bolts 74', optionally with locking rings. Subsequently, the hub cap 66 ', which is provided with radial through holes 88', possibly simultaneously with the perforation of the radial blind holes 86 'of the connecting ring 72' 72 ', and the dowels 90 are pressed into the holes 88', 86 '. Thereafter, the hole 88 'of the hub cap 66' to which the threaded section 92 'is provided is closed with a threaded plug 94', and preferably into the aft hub cap 66 ' . On the one hand, the screw plugs 94 'prevent any water entering the holes and corroding the holes and / or dowels therein and, on the other hand, In order to prevent dowels from escaping through the holes due to the centrifugal force acting on them.

The hub cap is installed at the rear end of the hub body so that its opposite end in the direction away from the hub body, i.e. its rear end, is not closed at all and the hub cap has the general shape of a truncated conical converging shell with an open interior. However, most of the interior of the hub cap is closed by the axial extension, i.e., the rear end cover of the hub body or the hub body itself. According to the first option, the axial length of the hub cap is smaller than the axial length of the axial extension. In other words, the hub cap partially covers only the axial extension, so that at the rear end of the hub cap there is a gap between itself and the axial extension, which gap is preferred It is not necessarily, it is about 10 to 30 mm, preferably about 20 mm. The main reason for such a gap is that at least the axial extension, possibly also the hub cap, is produced by casting which does not allow gaps with closer surface quality. In addition, this gap is considered adequate to ensure free circulation of water, i.e., efficient flushing of the interior of the hub cap.

According to the second option, the hub cap extends to the entire axial length of the axial extension, so there is a similar gap between the axial extension and the hub cap. According to the third option, the hub cap extends further from the hub than the axial extension. In this case again, there is a similar gap between the inner surface of the hub cap and the outermost edge of the axial extension.

The stud bolts used to fasten the connecting ring 72 of Figures 2a and 2b to the rear end of the hub body 42, i.e., the fastening bolts 76, for various optional configurations, , It should be appreciated that it is desirable to use one or more separate guide pins to facilitate the installation of the connecting ring on the aft end of the hub body. Of course, the guide pins may also be used in connection with the use of stud bolts. It should also be appreciated that the dowels 90, 90 'are preferably provided with a central blind screw hole or some other suitable means to facilitate separation of the dowels when the hub cap is removed from the hub. Another alternative is to use bolts instead of plugs and dowels to tighten the hub gap with respect to the connecting ring. In this case, it is preferable to use a thread in the connecting ring. According to a further embodiment of the invention, the connecting ring may be replaced with ring sectors comprising at least two holes for fastening bolts, or with separate connecting members comprising one hole for each fastening bolt have. However, from the perspective of positioning the connecting rings, sectors or separate connecting members, or actually the outer circumferential surfaces thereof, coaxial with the hub body, the use of an entire one-part ring allows the most desirable option to be.

While the invention has been described by way of illustration and example in connection with what are presently considered to be the most preferred embodiments of the invention, it is to be understood that the invention is not limited to the disclosed embodiments, Or variations thereof, as well as numerous other applications that fall within the scope of the present invention. Details referred to in connection with any of the above embodiments may be used in connection with other embodiments if such a combination is technically feasible.

Claims (22)

As marine propellers,
The propeller includes a hub having a hub body 42, 42 ', propeller blades 48 and a hub cap 66, 66' attached to the aft end of the hub body 42, 42 ' (40, 40 '),
The hub cap has an outer surface provided with fins 68,
The hub cap (66, 66 ') is fastened to the hub body (42, 42') by a separate circular connection ring (72, 72 ') coaxial with the hub body Propellers for ships. The method according to claim 1,
Characterized in that said connection rings (72, 72 ') are fastened to the interior of said hub caps (66, 66') from the outside of said hub caps (66, 66 '). 3. The method according to claim 1 or 2,
The connecting rings 72 and 72 'are connected to coaxial radial holes 88, 86; 88', 86 'of the hub caps 66 and 66' and to the connecting rings 72 and 72 ' Is fastened within the hub cap (66, 66 ') by press dowels (90, 90'). The method of claim 3,
The holes 88, 88 'of the hub cap 66, 66' have threaded sections 92, 92 '
Characterized in that said holes (88, 88 ') are closed and sealed by plugs (94, 94') screwed into said threaded sections (92, 92 ' prop. 5. The method according to any one of claims 1 to 4,
Characterized in that the connecting rings (72, 72 ') are fastened to the hub bodies (42, 42') by bolts (74, 74 '). 6. The method according to any one of claims 1 to 5,
The hub 40 includes a rear end cover 54 attached to the rear end of the hub body 42 by fastening bolts 76,
At least a portion of the fastening bolts 76 is provided with an axial threaded hole 78,
Characterized in that bolts (74) for fastening the hub cap (66) to the hub body (42) are screwed into the screw holes (78) at the at least part of the fastening bolt (76) prop. The method according to claim 6,
Wherein the distance rings (80) are located on the bolts (74) between the heads of the fastening bolts (76) and the connecting ring (72). 8. The method according to claim 6 or 7,
Characterized in that the bolts (74) are stud bolts. 6. The method according to any one of claims 1 to 5,
The connecting ring 72 'includes bolts 74' extending through axial holes 96 'of the connecting ring 72' into threaded holes 78 'of the hub body 42' Is directly fastened to the hub body (42 ') by means of a fastener (42). 10. The method according to any one of claims 1 to 9,
Characterized in that the hub caps (66, 66 ') converge in a direction away from the hub body (42, 42'). 11. The method of claim 10,
Characterized in that the hub caps (66, 66 ') generally have a frusto-conically converging shape of rotational symmetry. The method according to claim 10 or 11,
The hub body (42, 42 ') has an axial extension (54)
Characterized in that the hub cap (66, 66 ') at least partially covers the axial extension (54). 13. The method of claim 12,
Characterized in that the hub cap (66, 66 ') has a radial gap with respect to the axial extension (54) at its trailing end. The method according to claim 12 or 13,
The extending portion in the axial direction has a length in the axial direction, and
Characterized in that the hub caps (66, 66 ') extend up to the entire axial length of the axial extension (54). The method according to claim 12 or 13,
Characterized in that the axially extending portion (54) extends further from the hub body (42, 42 ') than the hub cap (66, 66'). 16. The method according to any one of claims 1 to 15,
Characterized in that the propeller is one of a fixed pitch propeller and a controllable pitch propeller. A method of installing a hub cap at a rear end of a hub of a propeller,
The propeller includes hubs 40, 40 'having hub bodies 42, 42', propeller blades 48 and hub caps 66, 66 '
The hub cap 62 has an outer surface provided with fins 68 and an inner surface having an inner diameter,
The method comprises:
a) fabricating a circular connecting ring (72, 72 ') having an outer diameter equal to the inner diameter of the hub cap (66, 66'),
b) providing radial through holes (88, 88 ') in the hub cap (66, 66'),
c) providing radially extending blind holes (86, 86 ') in said connecting ring (72, 72'),
d) providing axial through holes (96, 96 ') in said connecting ring (72, 72'),
e) providing threaded holes 78, 78 'in connection with the hub body 42, 42'
f) fastening the connecting rings 72, 72 'to the rear ends of the hub bodies 42, 42' by bolts 74, 74 'screwed into the threaded holes 78, 78' ,
g) mounting the hub caps (66, 66 ') on the connecting rings (72, 72'), and
h ') into the holes (88, 88; 86', 86 ') to fasten the hub caps (66, 66') to the circular connection rings (72, 72 ' Characterized in that it comprises the step of pressing the hub cap on the rear end of the hub of the propeller. 18. The method of claim 17,
After step b), provide the screw sections 92, 92 'in the holes 88, 88', and
, After step h), providing the plugs (94, 94 ') into the threaded sections (92, 92'). 18. The method of claim 17,
Wherein step b) and step c) are carried out at the same time. 18. The method of claim 17,
Characterized in that in step e), the threaded holes (78) are provided in at least part of the bolts (76) used to fasten the aft end cover (54) to the aft end of the hub body (42) , And installing the hub cap at the rear end of the hub of the propeller. 21. The method of claim 20,
Characterized in that the stud bolts (74) are screwed into the threaded holes (78, 78 ') after step e). 22. The method of claim 21,
Characterized in that the distance rings (80) are inserted on the stud bolts (74) before step f).

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