SE2251146A1

SE2251146A1 - Marine controllable-pitch propeller

Info

Publication number: SE2251146A1
Application number: SE2251146A
Authority: SE
Inventors: Johan Tell; Lars Johansson; Peter Carlsson
Original assignee: Volvo Penta Corp
Priority date: 2022-09-30
Filing date: 2022-10-03
Publication date: 2024-03-31
Also published as: WO2024068140A1

Abstract

A marine controllable -pitch propeller (1) to be mounted on a drive shaft (d), the marine controllable-pitch propeller (1) comprisinga propeller blade (10) comprising an offset pitch interface (11),a pitch adjusting member (20) that is adapted to be linearly movably mounted on the drive shaft (d) and connected to the offset pitch interface (11), such that a linear motion (A) of the pitch adjusting member (20) along the drive shaft (d) results in a pitch adjustment (P) of the propeller blade (10),a rotary actuator (30),a linear actuator (40) operationally arranged between the rotary actuator (30) and the pitch adjusting member (20), andtranslation means (31, 41) for translating a rotary motion (R) of the rotary actuator (30) about the drive shaft (d) into a linear motion (A) of the linear actuator (40) along the drive shaft (d), wherein the pitch adjusting member (20) is rotationally fixed to the propeller blade (10).

Description

TECHNICAL FIELD The present disclosure generally pertains to marine propellers, and more precisely to a marine controllable-pitch propeller. BAcKGRoUND Marine propellers are used to propel marine vehicles and/or to generate electricity to a marine vehicle from a Water current. Marine controllable-pitch propellers are conf1gured such that the blade pitch may be adjusted to optimise the propeller performance in a given situation. Typically, the pitch is adjustable by means of actuators that for example extend intemally or extemally a drive axis driving the propeller.

For example, the prior art document US3567340A discloses a controllable-pitch propeller in Which a rotationally stationary bearing ring With an annular slot is linearly displaceable to rotate a blade via an offset bearing received in the slot.

The prior art solutions are marred With various draWbacks in that they are complex in design and control, involve many moving parts and/or have a relatively short life. SUMMARY It is an object of the present disclosure to provide an improved marine controllable-pitch propeller, addressing the issues discussed above. The object is obtained by marine controllable- pitch propeller that is to be mounted on a drive shaft and that comprises a propeller blade With an offset pitch interface. The marine controllable-pitch propeller further comprises a pitch adjusting member that is adapted to be linearly movably mounted on the drive shaft and connected to the offset pitch interface, such that a linear motion of the pitch adjusting member results in a pitch adjustment of the propeller blade. There is further a rotary actuator, a linear actuator operationally arranged between the rotary actuator and the pitch adjusting member, and translation means for translating a rotary motion of the rotary actuator into a linear motion of the linear actuator. According to the present solution, the pitch adjusting member is rotationally fixed to the propeller blade.

This Way the pitch adjusting member rotates together With the propeller blade during use. Such a design may be sturdy and contribute to a long life. In addition, there may be little or no friction losses between the pitch adjusting member and the propeller blade. No bearing or similar friction-reducing element is needed between the pitch adjusting member and the propeller blade.

More precisely, the drive shaft may be rotationally fixed to the propeller blade that is rotationally fixed to the pitch adjusting member. Thus, the pitch adjusting member is rotationally fixed to the drive shaft via the propeller blade.

By the linear actuator being operationally arranged between the rotary actuator and the pitch adjusting member is meant that, in use (i.e. during operation), the rotary actuator affects the linear actuator that affects the pitch adjusting member. This may be referred to as the linear actuator being operationally positioned between the rotary actuator and the pitch adjusting member. As has been mentioned, a rotary motion of the rotary actuator affects a linear motion of the linear actuator that affects a linear motion of the pitch adjusting member.

According to one embodiment, the translation means is conf1gured such the angular difference between end positions of the rotatory actuator is at least 90 degrees. In other words, the rotary actuator may be rotated at least 90 degrees to change the propeller blade pitch from one end position to the other end position. Thereby a smooth and precise adjustment of the pitch is made possible. In addition, an extemal potentially pitch-changing force acting on the propeller blade may easily be withstood by the rotatory actuator. In other words, such an extemal force, e.g. from water, is not likely to cause the rotatory actuator to rotate. According to one embodiment, the translation means is conf1gured such that the angular difference between end positions of the rotatory actuator is at least 180 degrees, which may be yet further benef1cial for the reasons just mentioned. The present solution may even allow the rotary actuator being rotated several tums between its end positions.

Pitch adjustment of the propeller blade typically involves rotating the propeller blade along its length axis. Therefore, the offset pitch interface is typically positioned offset, i.e. at a radial distance from, the propeller blade length axis. The offset bearing of US3567340A forms an example of an offset pitch interface.

According to one embodiment, the translation means comprises thread means. A thread means may be particularly suitable for providing a precise adjustment of the pitch. The translation means may be an integral part of the rotary actuator and the linear actuator. For example, the rotary actuator and the linear actuator may both comprise cooperating, in other words mating, thread means. The thread means may be helical threads. The thread means may be referred to as screw threads.

According to one embodiment, the translation means comprise an intemal thread arranged on the rotary actuator and an extemal thread arranged on the linear actuator.

According to one embodiment, the linear actuator is arranged radially intemally the rotary actuator. Such a design may be compact and sturdy. The linear actuator may also be arranged axially intemally the rotary actuator. In other words, the linear actuator may be enclosed by the rotary actuator. The linear actuator may altematively protrude axially out from the rotary actuator when the rotary actuator is in one end position. In such rotary end position of the rotary actuator, the linear actuator may be positioned in an axial (linear) end position. More precisely in the axial end position in which the linear actuator is closest to the pitch adjusting member.

According to one embodiment, the translation means comprise thread means and the thread pitch of said thread means is selected such the angular difference between end positions of the rotatory actuator is at least 90 degrees. Said thread pitch may altematively be selected such that the angular difference is at least 180 degrees, or such that the rotary actuator may be rotated several complete tums between its end positions.

According to one embodiment, the offset pitch interface and the pitch adjusting member are configured to engage in a positive fit, which is a particularly sturdy connection. The offset pitch interface may be an integral part of the propeller blade, or may be attached to the propeller blade by a positive fit. Thus, the pitch adjusting member may be rotationally fixed to the propeller blade by a positive fit.

According to one embodiment, the offset pitch interface comprises a protruding member that extends parallel to and at a distance from a pitch axis of the propeller blade. During pitch adjustment of the propeller blade, the propeller blade may rotate around its pitch axis.

According to one embodiment, the pitch adjusting member comprises a receiving opening that is adapted to receive the above-mentioned protruding member. Altematively, the situation is the reverse such that the pitch adjusting member comprises a protruding member and the offset pitch interface comprises a receiving opening.

According to one embodiment, the pitch adjusting member comprises a number of separate receiving openings. Thereby, a number of propeller blades may be controlled simultaneously.

According to one embodiment, a bearing is arranged between the linear actuator and the pitch adjusting member. Said bearing, e. g. a ball bearing or a slide bearing, may reduce any frictional losses between linear actuator and the pitch adjusting member. The linear actuator does not rotate together With the propeller blade during use. The linear actuator is adapted to be linearly movably mounted on the drive shaft. The linear actuator is not rotationally fixed to the propeller blade. The linear actuator is not rotationally fixed to the drive shaft.

According to one embodiment, the linear actuator and the pitch adjusting member are linearly, in other Words axially, fixed to one another. If so, the linear actuator may cause a linear motion of the pitch adjusting member in both axial directions. For example, there may be circumferential grooves arranged on the linear actuator and on the pitch adjusting member, and a locking ring may be positioned in said grooves. The linear actuator and the pitch adjusting member may altematively be linearly fixed to one another by bearing means.

Altematively, the linear actuator and the pitch adjusting member are not linearly fixed to one another. If so, the linear actuator may cause a linear motion of the pitch adjusting member in one axial direction only. In other Words, the linear actuator may push, but not pull, the pitch adjusting member. The retum movement of the pitch adjusting member may e.g. be achieved by spring means.

Typically, a linear motion of the pitch adjusting member in a first (axial) direction results in a first pitch adjustment of the propeller blade Whereas a linear motion of the pitch adjusting member in an opposite direction results in an opposite pitch adjustment of the propeller blade.

According to one embodiment, the linear actuator comprises a rotation blocking interface that is adapted to be engaged by a stationary member to rotationally fix the linear actuator. The rotation blocking interface may be an axial though-hole or a recess in a radially outer surface of the linear actuator. The stationary member may be fixed to a stationary housing of the marine controllable-pitch propeller. The stationary member may extend in parallel With the drive shaft. When the stationary member, e. g. a pin or rod, engages the rotation blocking interface the linear actuator may slide along the drive shaft (and the stationary member) but not rotate around the drive shaft.

According to one embodiment, the marine controllable-pitch propeller comprises a movable housing that is rotationally fixed to the drive shaft. The marine controllable-pitch propeller may further comprise a stationary housing. Thus, in use, the movable housing rotates With the drive shaft Whereas the stationary housing does not. As has been mentioned, the linear actuator may be rotationally fixed to the stationary housing (by means of the rotation blocking interface and the stationary member). The rotary actuator may be rotatable with respect to the stationary housing for pitch adjustment of the propeller blade.

By the pitch adjusting member being rotationally fixed to the propeller blade is meant that both the propeller blade and the pitch adjusting member are brought to rotate by the drive shaft. When the propeller blade is brought to rotate by the drive shaft d, the pitch adjusting member and the propeller blade rotate at the same speed. The pitch adjusting member may be brought to rotate by the propeller blade.

Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a/an/the element, apparatus, component, means, step, etc." are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated. Further features of, and advantages with, the present invention will become apparent when studying the appended claims and the following description. The skilled person realizes that different features of the present invention may be combined to create embodiments other than those described in the following, without departing from the scope of the present invention. BRIEE DESCRIPTION oE THE DRAwINGs The above, as well as additional objects, features and advantages, will be better understood through the following illustrative and non-limiting detailed description of exemplary embodiments, wherein figure l is an isometric view of a marine controllable-pitch propeller and figure 2 is an axial cross-section through the marine controllable-pitch propeller of figure 1. DETAILED DESCRIPTION The present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments are shown. The disclosure may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided for thoroughness and completeness. Like reference characters refer to like elements throughout the description.

Figures 1 and 2 illustrate an example marine controllable-pitch propeller 1 (hereinafter propeller). The propeller 1 is mounted on a drive shaft d, the ultimate end of which is shown in figures 1 and 2. The propeller 1 typically comprises two to six propeller blades, one propeller blade 10 being illustrated herein. As is shown in figure 1, the propeller blade 10 comprises an offset pitch interface 11.

The propeller 1 further comprises a pitch adjusting member 20, a rotary actuator 30, a linear actuator 40 and translation means 31, 41.

The offset pitch interface 1 1 (not shown in figure 2) is in this embodiment a protruding member that extends parallel to and at a distance from a pitch axis of the propeller blade. The protruding member is embodied as a pin. The pin is of circular cross-section.

The pitch adjusting member 20 is adapted to be linearly movably mounted on the drive shaft d. In other words, the pitch adjusting member 20 may be free to slide axially along the drive shaft d. The present pitch adjusting member 20 comprises a through-opening of circular cross- section through which the drive shaft d passes. The pitch adjusting member 20 is preferably not rotationally fixed directly to the drive shaft d, such that the pitch adjusting member 20 may easily slide along the drive shaft d.

As is apprehended from figure 1, a linear motion A (along the drive shaft d, as indicated if figure 1) of the pitch adjusting member 20 results in a pitch adjustment of the propeller blade 10. This because the pitch adjusting member 20 is connected to the offset pitch interface 11. Similarly, in US3567340A a linear motion of the bearing ring (item 20) results in a rotation of the propeller blades (item 11). A pitch adjustment P of the propeller blade 10 corresponds to a rotation (as indicated in figure 1) of the propeller blade 10 around its pitch axis. The pitch axis extends longitudinally and centrally through the propeller blade 10.

The pitch adjusting member 20 is rotationally fixed to the propeller blade 10. In the present embodiment, the pitch adjusting member 20 comprises a receiving opening 21 that is adapted to receive the protruding member (offset pitch interface 11). The receiving opening is embodied as a recess in an outer surface of the pitch adjusting member 20. The receiving opening 21 may e.g. be of circular or square cross-section.

As is illustrated, the propeller blade 10 is rotationally joumalled and when the pitch adjusting member 20 is moved axially A along the drive shaft d, the offset pitch interface 11 is moved with respect to the pitch axis of the propeller blade 10. The propeller blade 10 is thereby forced to rotate or pivot P around its pitch axis as the offset pitch interface 11 is distanced from the pitch axis.

The pitch adjusting member 20 may comprise a first portion 22, a second portion 23 and a third portion 24. The first portion 22 may, as is illustrated, extend into the linear actuator 40. The first portion 22 may be sleeve-shaped. The second, or central, portion 23 may comprise the receiving opening(s) 21 and may be essentially box-shaped. In more detail, the second portion 23 may comprise a number (here four) of side faces wherein some (here two) or all comprise receiving openings 21. The third portion 24 may be disc-shaped and may have a larger radial extension than the first 22 and second 23 portions.

The linear actuator 40 is arranged to linearly move the pitch adjusting member 20, in other words axially move the latter along the drive shaft d. The linear actuator is embodied as a hollow circular cylinder. As is described below, the cylinder may comprise extemal threads 41. The linear actuator 40 is adapted to be linearly movably mounted on the drive shaft d. The present linear actuator 40 comprises a through-opening of circular cross-section through which the drive shaft d passes. The linear actuator 40 is not rotationally fixed to the drive shaft d.

In the present embodiment, the linear actuator 40 is arranged adjacent the pitch adjusting member 20 and may push the latter in one axial direction along the drive shaft d. Referring in particular to figure 2, the linear actuator 40 may push the pitch adjusting member 20 towards the propeller blade 10, i.e. to the right in figure 2. The linear actuator 40 may be arranged directly adj acent the pitch adjusting member 20, or there may be a bearing (not shown) between the linear actuator 40 and the pitch adjusting member 20.

The rotary actuator 30 is controllable, more precisely rotatable R (as indicated in figure 1), to adjust the pitch of the propeller blade 10. The rotary actuator 30 may be referred to as an input actuator. The rotary actuator 30 may, as is disclosed, comprise a control interface 32, or control input interface, that may be conf1gured to interact with an extemal control device. Preferably, the control interface 32 is adapted for forrning a positive fit with the extemal control device. The control interface 32 may, as shown, be embodied as teeth on the outer surface of the rotary actuator 30. The teeth 32 may be engaged by a chain (not shown) or a gear (not shown) forrning part of the extemal control device. Altematively, a belt connection or another connection may be provided between the extemal control device and the rotary actuator 30, and the latter may be configured accordingly.

The present linear actuator 40 comprises a rotation blocking interface 43 that is engaged by at least one stationary member (not shown) to rotationally fix the linear actuator 40. The rotation blocking interface 43 is in the present case a recess (see figure 2) in the radially outer surface of the linear actuator 40. In other embodiments, the rotation blocking interface 43 may be one or more through-holes made in the linear actuator 40, each engaged by a stationary member.

The stationary member may be fixed to the stationary housing 3 (described below).

The stationary member may extend through the rotary actuator 30 and in parallel with the drive shaft d and through the recess 43 (or through-hole). Thus, the rotary actuator 30 need not comprise a closed outer side wall (left in the figures) but may be at least partly open such that the stationary member may extend there through.

The translation means 3 1, 41 are configured to translate, in other words or convert or transforrn, a rotary motion of the rotary actuator 30 into a linear motion of the linear actuator 40. In the present embodiment, the translation means comprise thread means. The thread pitch may be selected such the angular difference between end positions of the rotatory actuator 30 is at least 90 degrees, at least 180 degrees, or such that the rotary actuator 30 may be rotated several tums between its end positions.

The translation means 31, 41 is here embodied as an integral part of the rotary actuator 30 and the linear actuator 40. As is illustrated in figure 2, the rotary actuator 30 may comprise an intemal thread 31 that that cooperates with an extemal thread 41 on the linear actuator 40.

The present propeller 1 comprises a movable housing 2 and a stationary housing 3 (only partly and schematically illustrated). The movable housing 2 is rotationally fixed to the drive shaft d. In the present example, the movable housing 2 is fixed, i.e. rotationally fixed, to the drive shaft d at the right hand end of the movable housing 2. When the propeller blade(s) 10 is rotated by the drive shaft d, the movable housing 2 rotates with the drive shaft d whereas the stationary housing 3 does not. The rotary motion is in the present embodiment transferred from the drive shaft d to the movable housing 2, and then via the propeller blade 10 to the pitch adjusting member 20.

Next, a use or operation of the propeller 1 will be described. When an operator or a control system of a marine vehicle demands a pitch adjustment of the propeller blade(s) 10, the rotary actuator 30 is rotated (for example by the extemal control device). Before being brought to rotate, the rotary actuator 30 is stationary. The rotary actuator 30 may for example be attached to the stationary housing 3. Hence, the rotary actuator 30 is not rotationally fixed to the drive shaft d. During pitch adjustment, the rotary actuator 30 may be rotated with respect to the stationary housing 3. During pitch adjustment, the rotary actuator 30 is rotated with respect to the linear actuator 40.

The rotation of the rotary actuator 30 with respect to the linear actuator 40 is translated into a linear (right) movement of the linear actuator 40, by means of the respective threads 31, 41 described above. The linear actuator 40 is brought to move linearly along the drive shaft d. The linear actuator 40 does not rotate, as has been describe above (stationary member and rotation blocking interface 43). The linear actuator 40 may be enclosed within the rotary actuator 30 as the linear actuator 40 travels axially inside the rotary actuator 30.

The linear movement of the linear actuator 40 causes the pitch adjusting member 20 move linearly (to the right) along the drive shaft d. The movement of the linear actuator 40 along the drive shaft d rotates the propeller blade(s) 10 such that the pitch is adjusted, as has been described. The blade pitch may be controlled in idle condition, when the drive shaft d brings the blades 10 to rotate, and when the blades 10 bring the drive shaft d to rotate.

When the pitch of the propeller blade(s) 10 is to be adjusted in the opposite direction, the pitch adjusting member 20 is moved linearly (to the left) along the drive shaft d in the opposite direction. The pitch adjusting member 20 may be moved in both directions by the rotary actuator 30 being rotated, or spring means (not shown) may be arranged to push the pitch adjusting member 20 towards the linear actuator 40 for the retum movement. For example, a compression spring may be positioned between the pitch adjusting member 20 and the movable housing 2. More precisely, the compression spring may be positioned between the third portion 24 of the pitch adjusting member 20 and a surface of the movable housing 2 that faces the third portion 24. Such possible spring location 25 is indicated in figure 2.

The terrninology used herein is for the purpose of describing particular aspects only and is not intended to be limiting of the disclosure. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items. It will be further understood that the terms "comprises," "comprising," "includes," and/or "including" when used herein specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof It will be understood that, although the terms first, second, etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be terrned a second element, and, similarly, a second element could be terrned a first element without departing from the scope of the present disclosure.

Relative terms such as "below" or "above" or "upper" or "lower" or "horizontal" or "vertical" may be used herein to describe a relationship of one element to another element as illustrated in the Figures. It will be understood that these terms and those discussed above are intended to encompass different orientations of the device in addition to the orientation depicted in the Figures. It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element, or intervening elements may be present. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements present.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

It is to be understood that the present disclosure is not limited to the aspects described above and illustrated in the drawings; rather, the skilled person will recognize that many changes and modifications may be made within the scope of the present disclosure and appended claims. In the drawings and specification, there have been disclosed aspects for purposes of illustration only and not for purposes of limitation, the scope of the inventive concepts being set forth in the following claims.

Claims

CLAIMS A marine controllable-pitch propeller (1) to be mounted on a drive shaft (d), the marine controllable-pitch propeller (1) comprising a propeller blade (10) comprising an offset pitch interface (11), - a pitch adjusting member (20) that is adapted to be linearly movably mounted on the drive shaft (d) and connected to the offset pitch interface (11), such that a linear motion (A) of the pitch adjusting member (20) along the drive shaft (d) results in a pitch adjustment (P) of the propeller blade (10), - a rotary actuator (3 0), - a linear actuator (40) operationally arranged between the rotary actuator (30) and the pitch adjusting member (20), and - translation means (31, 41) for translating a rotary motion (R) of the rotary actuator (3 0) about the drive shaft (d) into a linear motion (A) of the linear actuator (40) along the drive shaft (d), wherein the pitch adjusting member (20) is rotationally fixed to the propeller blade (10). The marine controllable-pitch propeller (1) of claim 1, wherein the translation means (31, 41) is configured such the angular difference between end positions of the rotatory actuator (30) is at least 90 degrees. . The marine controllable-pitch propeller (1) of claim 1, wherein the translation means (31, 41) is conf1gured such that the angular difference between end positions of the rotatory actuator (30) is at least 180 degrees. The marine controllable-pitch propeller (1) of any preceding claim, wherein the translation means (31, 41) comprise thread means. The marine controllable-pitch propeller (1) of any preceding claim, wherein the translation means (31, 41) comprise an intemal thread (31) arranged on the rotary actuator (3 0) and an extemal thread (41) arranged on the linear actuator (40). The marine controllable-pitch propeller (1) of claim 5, wherein the linear actuator (40) is arranged radially intemally the rotary actuator (3 0). The marine controllable-pitch propeller (1) of any one of claims 4 to 6, Wherein the thread pitch of the thread means is selected such the angular difference between end positions of the rotatory actuator (30) is at least 90 degrees. The marine controllable-pitch propeller (1) of any preceding claim, Wherein the offset pitch interface (11) and the pitch adjusting member (20) are configured to engage in a positive fit. The marine controllable-pitch propeller (1) of any preceding claim, Wherein the offset pitch interface (1 1) comprises a protruding member that extends parallel to and at a distance from a pitch axis of the propeller blade (10). The marine controllable-pitch propeller (1) of claim 9, Wherein the pitch adjusting member (20) comprises a receiving opening (21) that is adapted to receive the protruding member. The marine controllable-pitch propeller (1) of claim 10, Wherein the pitch adjusting member (20) comprises a number of separate receiving openings (21). The marine controllable-pitch propeller (1) of any preceding claim, Wherein a bearing is arranged between the linear actuator (40) and the pitch adjusting member (20). The marine controllable-pitch propeller (1) of any preceding claim, Wherein the linear actuator (40) and the pitch adjusting member (20) are linearly fixed to one another. The marine controllable-pitch propeller (1) of any preceding claim, Wherein the linear actuator (40) comprises a rotation blocking interface (43) that is adapted to be engaged by a stationary member to rotationally fix the linear actuator (40). The marine controllable-pitch propeller (1) of any preceding claim comprising a movable housing (2), Which is rotationally fixed to the drive shaft (d), and a stationary housing (3), Wherein the linear actuator (40) is rotationally fixed to the stationary housing (3) and the rotary actuator (30) is rotatable With respect to the stationary housing (3) for pitch adjustment of the propeller blade (10).