JP7222531B2 - marine propeller - Google Patents

Description

The present invention relates to marine propellers.

2. Description of the Related Art Propellers for ships employing fiber-reinforced plastic blades have been known (see Patent Documents 1 and 2). Such marine propellers are constructed by inserting the base of the blade into the groove of the boss.

In such a marine propeller, when a large load is applied to the blades, the blades are deformed and the pitch angle becomes small. For example, when a large load is applied to the blade during acceleration, towing, or due to rough weather, the blade deforms and the pitch angle becomes smaller. Further, when a large load is applied to the blade due to the wake speed difference behind the hull, the blade is deformed and the pitch angle becomes small. Therefore, it is possible to prevent an excessive load from being applied to the engine and suppress the occurrence of cavitation.

By the way, when the marine propeller is rotating, a moment acts to push down the blades. In other words, when the marine propeller is rotating, a large load is applied to the advancing surface of the blade, and a moment acts to push the blade forward. Therefore, there is a problem that a load is applied locally to the inner wall surface forming the groove of the boss, and the stress in the vicinity of the groove of the boss increases. In addition, there is also the problem that the outer wall surface forming the base of the blade is also locally loaded, and the contact pressure at this portion increases.

Here, the problems in conventional marine propellers will be described in detail with reference to FIGS. 11 to 13. FIG. These figures are a combination of calculation models of the boss 6 and the blade 7 (the base 71 of the blade 7 is inserted into the groove 61 of the boss 6). In these figures, an arrow R indicates the direction of rotation of the marine propeller. In these figures, an arrow M indicates a moment that tends to push down the blade 7. As shown in FIG.

In a conventional marine propeller, the groove 61 of the boss 6 is a so-called dovetail groove, and has a tapered cross-sectional shape in which inner wall surfaces 61s on both sides gradually approach toward the radially outer side. The base 71 of the blade 7 is a so-called dovetail, and has a tapered cross-sectional shape in which the outer wall surfaces 71s on both sides gradually approach toward the radially outer side. The marine propeller is constructed by inserting the base portion 71 of the blade 7 into the groove portion 61 of the boss 6 .

As described above, when the marine propeller is rotating, a moment acts to push down the blades 7 (see arrow M in FIG. 11). When a moment acts to push down the blade 7, a large load acts on the base 71, which is a fixed portion of the blade 7, to rotate it. Then, a large load acts on the inner wall surfaces 61s on both sides of the groove portion 61 that constrains the base portion 71 as well.

Specifically, a large load F1 is applied to the radially outer portion of the inner wall surface 61s on the tilting direction side (the side opposite to the rotation direction of the marine propeller). Therefore, this portion is pushed upward in the radial direction by the load F1 and the sliding movement of the base portion 71 along the inner wall surface 61s (see the two-dot chain line in FIG. 11). Therefore, there is a problem that the displacement in this portion becomes large (see region D1 in FIG. 12A) and the stress increases (see region S1 in FIG. 12B). Moreover, since the load F1 tries to widen the groove width dimension W of the groove portion 61, there is a problem that the stress increases even in the curved portion connecting the inner wall surface 61s and the bottom wall surface 61t ((B) in FIG. 12). (see region S2 in ).

Further, when focusing on the base 71 of the blade 7, a load F2 opposing the load F1 is applied to the outer wall surface 71s of the base 71 on the tilting direction side (counter-rotating direction side of the marine propeller) based on the law of action and reaction. It will happen. Therefore, there is also a problem that the contact pressure in this portion becomes large (see region P1 in (B) of FIG. 13).

On the other hand, a large load F3 is applied to the radially inner portion of the inner wall surface 61s on the opposite side of the tilting direction (rotation direction side of the marine propeller). For this reason, the portion is pushed upward in the radial direction by the load F3 and the movement of the base portion 71 to slide along the inner wall surface 61s (shear deformation occurs in the radial direction outward: in FIG. 11). (See double-dotted line). Therefore, there is a problem that the displacement in this portion becomes large (see region D3 in FIG. 12A) and the stress becomes large (see region S3 in FIG. 12B). Further, since the load F3 tries to widen the groove width dimension W of the groove portion 61, there is a problem that the stress is increased even in the curved portion connecting the inner wall surface 61s and the bottom wall surface 61t ((B) of FIG. 12). (see region S4 in ).

Further, focusing on the base 71 of the blade 7, a load F4 opposing the load F3 is applied to the outer wall surface 71s of the base 71 on the opposite tilting direction side (rotation direction side of the ship propeller) based on the law of action and reaction. It will happen. Therefore, there is also a problem that the contact pressure in this portion becomes large (see region P2 in (B) of FIG. 13).

JP 2014-125055 A JP 2012-66699 A

To provide a marine propeller constructed by inserting a base of a blade into a groove of a boss, capable of reducing stress in the vicinity of the groove of the boss and reducing contact pressure on the surface of the base of the blade.

The first invention is
a boss having a groove formed on its outer peripheral surface;
a blade having a base formed on one end side,
A marine propeller configured by inserting the base of the blade into the groove of the boss,
a protrusion is provided on the inner wall surface forming the groove of the boss and extends along the insertion direction of the base of the blade;
An outer wall surface constituting the base of the blade is provided with a recessed portion extending along the insertion direction of the base of the blade,
When the base of the blade is inserted into the groove of the boss, the protrusion and the depression are engaged with each other , and
The apex of the protruding portion and both slanted surfaces thereof and the bottom point of the recessed portion and both slanted surfaces thereof are fitted to each other so as not to form a gap.

A second invention is a marine propeller according to the first invention,
the inner wall surface radially outward of the apex of the protrusion is inclined in the direction of widening the groove width dimension toward the radially outer side,
the outer wall surface radially outward of the bottom point of the recessed portion is inclined in a direction in which the thickness of the base increases as it extends radially outward;
The inner wall surface and the outer wall surface are in contact with each other.

A third invention is a marine propeller according to the first or second invention,
The inner wall surface radially inner than the vertex of the protrusion is inclined in the direction of widening the groove width dimension as it goes radially inward,
The outer wall surface radially inner than the bottom point of the depressed portion is inclined in a direction in which the thickness of the base increases as it goes radially inward,
The inner wall surface and the outer wall surface are in contact with each other.

A fourth invention is a marine propeller according to any one of the first to third inventions,
The outer edge of the inner wall surface is aligned with the outer edge of the outer wall surface, and a curved portion is formed from the outer edge of the outer wall surface and connected to the wing body.

In the marine propeller according to the first aspect of the invention, the protrusion is provided on the inner wall surface forming the groove of the boss and extends along the insertion direction of the base of the blade. Further, a depression is provided in the outer wall surface forming the base of the blade and extends along the insertion direction of the base of the blade. When the base of the blade is inserted into the groove of the boss, the protruding portion and the recessed portion are engaged. According to such a marine propeller, even if a moment acts to push down the blade and a load is locally applied to the inner wall surface forming the groove of the boss, the stress in the vicinity of the groove of the boss can be reduced. It becomes possible. Moreover, even if a load is locally applied to the outer wall surface forming the base of the blade, it is possible to reduce the contact pressure on the surface of the base of the blade.

In the marine propeller according to the second aspect of the invention, the inner wall surface on the radially outer side of the apex of the protruding portion is inclined in the direction of increasing the groove width dimension toward the radially outer side. Further, the outer wall surface radially outward of the bottom point of the depressed portion is inclined in the direction of increasing the thickness of the base portion toward the radially outer side. Then, the inner wall surface and the outer wall surface are brought into contact with each other. According to such a marine propeller, even if a load is applied to the radially outer portion of the inner wall surface, it is possible to reduce the stress in the vicinity of the groove portion of the boss. Moreover, even if a load is applied to the radially outer portion of the outer wall surface, it is possible to reduce the contact pressure on the base surface of the blade.

In the marine propeller according to the third aspect of the invention, the inner wall surface radially inward of the apex of the protruding portion is inclined in the direction of widening the groove width as it goes radially inward. In addition, the outer wall surface radially inward of the bottom point of the depressed portion is inclined in a direction in which the thickness of the base increases as it goes radially inward. Then, the inner wall surface and the outer wall surface are brought into contact with each other. According to such a marine propeller, even if a load is applied to the radially inner portion of the inner wall surface, it is possible to reduce the stress in the vicinity of the groove portion of the boss. Moreover, even if a load is applied to the radially inner portion of the outer wall surface, it is possible to reduce the contact pressure on the base surface of the blade.

In a ship propeller according to a fourth aspect of the invention, the outer edge of the inner wall surface and the outer edge of the outer wall surface are aligned, and a curved portion is formed from the outer edge of the outer wall surface to connect to the wing body. According to such a marine propeller, since the rigidity of the wing body portion is increased, it is possible to suppress the local load from being applied to the inner wall surface and to reliably reduce the stress in the vicinity of the groove portion of the boss. In addition, since the rigidity of the blade body portion is increased, it is possible to suppress the local load from being applied to the outer wall surface and to reliably reduce the contact pressure on the base surface of the blade.

The figure which shows a propeller for ships. A diagram showing a boss. The figure which shows a blade. The figure which shows a retainer. The figure which shows the process of attaching a blade to a boss|hub. The figure which shows the process which attaches a retainer to a boss|hub. FIG. 4 shows the groove of the boss and the base of the blade; The figure which shows the state which combined the groove part of a boss|hub, and the base of a blade. FIG. 4 is a diagram showing displacement distribution and stress distribution in the vicinity of a groove portion of a boss; The figure which shows the displacement distribution and contact pressure distribution in the base of a blade. (Conventional structure) The figure which shows the state which combined the groove part of a boss|hub, and the base part of a blade. (Conventional structure) The figure which shows the displacement distribution and stress distribution in the vicinity of the groove part of a boss|hub. (Conventional structure) The figure which shows the displacement distribution and contact pressure distribution in the base of a blade.

First, a ship propeller 1 according to the present invention will be briefly described with reference to FIGS. 1 to 6. FIG. In the present application, "radially inward" means a direction perpendicularly approaching the rotational axis A of the marine propeller 1, and "radial outward" means a direction perpendicularly away from the rotational axis A of the marine propeller 1. means.

The marine propeller 1 converts the driving force of an engine into propulsive force. A marine propeller 1 mainly includes a boss 2 , blades 3 and a retainer 4 . Although the ship propeller 1 is a so-called four-blade propeller, it is not limited to this. Further, although the marine propeller 1 is a so-called high-skew propeller, it is not limited to this.

Boss 2 is attached to the propeller shaft. The boss 2 is made by cutting a metal (for example, aluminum bronze) molding. A groove portion 21 is formed on the outer peripheral surface of the boss 2 . The groove portion 21 has a spiral shape that turns rightward about the rotation axis A. As shown in FIG. The groove portion 21 is a so-called dovetail groove, and has a tapered cross-sectional shape in which the inner wall surfaces 21s on both sides gradually approach toward the outside in the radial direction unless projections 22, which will be described later, are taken into account ((A )). The boss 2 also has four bolt holes 23 extending forward from the rear end surface 2r. Each bolt hole 23 is provided in the vicinity of the left side of the opening end of each groove portion 21 (near the left turning side centering on the rotation axis A).

A blade 3 is attached to the boss 2 (see FIG. 5). The blade 3 is produced by subjecting a fiber-reinforced plastic (for example, carbon fiber-reinforced plastic) molding to a surface treatment or the like. The blade 3 has a base portion 31 formed on one end side thereof. The base portion 31 has a helical shape that turns rightward like the groove portion 21 of the boss 2 . The base portion 31 is a so-called dovetail, and unless a depressed portion 32, which will be described later, is taken into account, the outer wall surfaces 31s on both sides gradually taper toward the other end (the radially outer side when the blade 3 is attached to the boss 2). It has a tapered cross-sectional shape that approaches (see the two-dot chain line in FIG. 7B). Further, the blade 3 has a wing body portion 33 integrally formed with the base portion 31 . The wing body portion 33 has a sweepback angle larger than that of a general wing shape.

The retainer 4 is attached to the boss 2 (see FIG. 6). The retainer 4 is produced by cutting a metal (for example, aluminum bronze) molding. The retainer 4 has an annular shape with a hole 41 in the center. Further, the retainer 4 is provided with four bolt insertion holes 43 that penetrate forward from the rear end surface 4r. Each bolt insertion hole 43 is provided at a position overlapping the bolt hole 23 when the retainer 4 is attached. Each bolt insertion hole 43 has a shape in which a large-diameter hole portion in which the head of the bolt 44 is received and a small-diameter hole portion in which the shaft portion of the bolt 44 is received are connected. Therefore, even if the retainer 4 is attached using the bolts 44 , the heads of the bolts 44 do not protrude from the rear end surface 4 r of the retainer 4 . The retainer 4 is provided with a plurality of bolt holes 45 extending forward from the rear end surface 4r. These bolt holes 45 are used when attaching a cap (not shown).

Next, with reference to FIG. 7, a characteristic part of the propeller 1 for a marine vessel will be described. FIG. 7 shows a calculation model of the boss 2 and the blade 3 used for computer simulation. These computational models are simplified enough to give confidence in the simulation results.

In this marine propeller 1 , a protrusion 22 is provided on an inner wall surface 21 s forming a groove 21 of the boss 2 . The protruding portion 22 passes through the most radially outer point (hereinafter referred to as “outer edge Pa”) of the inner wall surface 21s and is in contact with the curved portion connecting the inner wall surface 21s and the bottom wall surface 21t (see two-dot chain line). It is the raised part. The projecting portion 22 extends along the insertion direction of the base portion 31 . Therefore, the projecting portion 22 appears as a convex shape extending continuously in an arc shape (see FIG. 5). However, the detailed shape of the projecting portion 22 is not limited.

On the other hand, in this marine propeller 1 , depressions 32 are provided in the outer wall surface 31 s forming the bases 31 of the blades 3 . The recessed portion 32 passes through the most radially outer point of the outer wall surface 31s (hereinafter referred to as “outer edge Pb”) and is in contact with the curved portion connecting the outer wall surface 31s and the bottom wall surface 31t (see the chain double-dashed line). This is the part that is sunken. The depressed portion 32 extends along the insertion direction of the base portion 31 . Therefore, the depressed portion 32 appears as a recessed shape extending continuously in an arc (see FIG. 5). However, the detailed shape of the depressed portion 32 is not limited.

By doing so, when the base portion 31 of the blade 3 is inserted into the groove portion 21 of the boss 2, the protruding portion 22 and the depressed portion 32 are fitted together (see FIG. 5). At this time, the apex 22p of the protrusion 22 and both slopes thereof and the bottom point 32b of the recessed portion 32 and both slopes are in contact with each other, so that no gap is formed. Further, when the base portion 31 of the blade 3 is inserted into the groove portion 21 of the boss 2, the rear end surface 31r of the base portion 31 is designed to slightly protrude from the rear end surface 2r of the boss 2 (see FIG. 6). Therefore, when the retainer 4 is attached, the base 31 of the blade 3 is pushed in with an appropriate load. Thus, the blade 3 is completely fixed to the boss 2 without rattling.

Next, with reference to FIGS. 7 to 10, the characteristic parts of the marine propeller 1 will be described, and the effects thereof will be described. These figures are a combination of calculation models of the boss 2 and the blade 3 (the base 31 of the blade 3 is inserted into the groove 21 of the boss 2). In these figures, the direction of rotation of the marine propeller 1 is indicated by an arrow R. As shown in FIG. In these figures, an arrow M indicates a moment that tends to push down the blade 3. As shown in FIG.

As described above, when the marine propeller 1 is rotating, a moment acts to push down the blades 3 . When a moment acts to push down the blade 3, a large load acts on the base 31, which is a fixed portion of the blade 3, to rotate it. Then, a large load acts on the inner wall surfaces 21s on both sides of the groove portion 21 that constrains the base portion 31 as well.

Specifically, the inner wall surface 21s on the tilting direction side (the side opposite to the rotation direction of the marine propeller 1) has a radially outer portion (a portion radially outer than the vertex 22p) of the inner wall surface 21s. 211") is subjected to a large load F1. In the marine propeller 1, the fitting of the projecting portion 22 and the recessed portion 32 prevents the base portion 31 from sliding along the inner wall surface 21s. In addition, since the inner wall surface 211 receives the load F1 at a large angle close to vertical, displacement in the vicinity of the inner wall surface 211 can be suppressed (see area D1 in FIG. 9A). Therefore, it is possible to reduce the stress in this portion (see region S1 in (B) of FIG. 9). In addition, it is possible to reduce the stress in the curved portion connecting the inner wall surface 21s and the bottom wall surface 21t (see region S2 in FIG. 9B).

Further, focusing on the base portion 31 of the blade 3, on the outer wall surface 31s of the base portion 31 on the tilting direction side (counter-rotating direction side of the marine propeller 1), there is a load F2 that opposes the load F1 based on the law of action and reaction. It will hang. In the ship propeller 1, the outer wall surface 31s (hereinafter referred to as the "inner wall surface 311") receives the load F2 at a large angle close to vertical, so displacement in the vicinity of the outer wall surface 311 can be suppressed (see FIG. 10). See area D2 in (A)). As described above, in the marine propeller 1, even if a moment that tends to push down the blades 3 acts, the displacement of the bases 31 of the blades 3 can be suppressed to prevent uneven contact. The pressure can be reduced (see area P1 in (B) of FIG. 10).

On the other hand, the inner wall surface 21s on the opposite tilting direction side (rotational direction side of the marine propeller 1) has a radially inner portion of the inner wall surface 21s (a portion radially inner than the vertex 22p: hereinafter referred to as an “inner wall surface 212”). ) is subjected to a large load F3. In the marine propeller 1, the fitting of the projecting portion 22 and the recessed portion 32 prevents the base portion 31 from sliding along the inner wall surface 21s. shear deformation does not occur). In addition, since the inner wall surface 212 receives the load F3 at a large angle close to vertical, displacement in the vicinity of the inner wall surface 212 can be suppressed (see region D3 in FIG. 9A). Therefore, it is possible to reduce the stress in this portion (see region S3 in (B) of FIG. 9). Moreover, it is possible to reduce the stress in the curved portion connecting the inner wall surface 21s and the bottom wall surface 21t (see region S4 in FIG. 9B).

Further, focusing on the base portion 31 of the blade 3, on the outer wall surface 31s of the base portion 31 on the opposite tilting direction side (rotating direction side of the marine propeller 1), there is a load F4 opposing the load F3 based on the law of action and reaction. It will hang. In the ship propeller 1, the outer wall surface 31s (hereinafter referred to as the "inner wall surface 312") receives the load F4 at a large angle close to vertical, so displacement in the vicinity of the outer wall surface 312 can be suppressed (see FIG. 10). See region D4 in (A)). As described above, in the marine propeller 1, even if a moment that tends to push down the blades 3 acts, the displacement of the bases 31 of the blades 3 can be suppressed to prevent uneven contact. The pressure can be reduced (see region P2 in (B) of FIG. 10).

As described above, in the marine propeller 1 , the protrusion 22 is provided on the inner wall surface 21 s forming the groove 21 of the boss 2 and extends along the insertion direction of the base 31 of the blade 3 . Further, a depressed portion 32 is provided in an outer wall surface 31s forming the base portion 31 of the blade 3 and extends along the direction in which the base portion 31 of the blade 3 is inserted. When the base portion 31 of the blade 3 is inserted into the groove portion 21 of the boss 2, the protruding portion 22 and the depressed portion 32 are fitted together. According to the marine propeller 1, even if a moment acts to push down the blades 3 and a load is locally applied to the inner wall surface 21s forming the groove 21 of the boss 2, the groove 21 of the boss 2 and its vicinity will not move. It is possible to reduce the stress in Further, even if a load is locally applied to the outer wall surface 31s forming the base 31 of the blade 3, the contact pressure on the surface of the base 31 of the blade 3 can be reduced.

Next, another characteristic part of the propeller 1 for a ship will be described with reference to FIGS. 7 to 10, and the effect thereof will be described. Here, the inner wall surface 21s on the radially outer side of the vertex 22p is referred to as the "inner wall surface 211" on both sides, and the inner wall surface 21s on the radially inner side of the vertex 22p is referred to as the "inner wall surface 212" on both sides. The outer wall surfaces 31s radially outside the bottom point 32b are both referred to as "outer wall surfaces 311", and the outer wall surfaces 31s radially inner than the bottom point 32b are both referred to as "inner wall surfaces 312".

In the marine propeller 1, the inner wall surface 211 is inclined in a direction in which the groove width W is widened toward the radially outer side. Therefore, the groove width dimension W on the radially outer side is larger than the groove width dimension W on the vertex 22p of the projecting portion 22 . On the other hand, the outer wall surface 311 is inclined in a direction in which the base portion thickness dimension T increases toward the radially outer side. Therefore, the base thickness dimension T on the radially outer side is larger than the base thickness dimension T at the bottom point 32b of the depressed portion 32 . Therefore, when the base portion 31 of the blade 3 is inserted into the groove portion 21 of the boss 2, the inner wall surface 211 and the outer wall surface 311 are completely in contact with each other without any gap.

This is because the inner wall surface 211 on the side of the tilting direction (the side opposite to the rotation direction of the marine propeller 1) receives the load F1 at a large angle close to vertical. This is also because the outer wall surface 311 receives the load F2 at a large angle close to vertical. In addition, the same technical idea is applied not only to the tilting direction side (counter-rotating direction side of the marine propeller 1) but also to the anti-tilting direction side (rotating direction side of the marine propeller 1). This is because the effect can be obtained regardless of the rotating direction of the propeller 1 for use. However, it may be applied only to the tilting direction side (counter-rotating direction side of the marine propeller 1).

As described above, in the marine propeller 1, the inner wall surface 211 radially outside the apex 22p of the protruding portion 22 is inclined in the direction in which the groove width dimension W widens as it goes radially outward. Further, the outer wall surface 311 radially outward of the bottom point 32b of the recessed portion 32 is inclined in the direction of widening the base thickness dimension T as it goes radially outward. Then, the inner wall surface 211 and the outer wall surface 311 are brought into contact with each other. According to the marine propeller 1, even if a load is applied to the radially outer portion (the inner wall surface 211) of the inner wall surface 21s, the stress in the vicinity of the groove portion 21 of the boss 2 can be reduced. Further, even if a load is applied to the radially outer portion (outer wall surface 311) of the outer wall surface 31s, the contact pressure on the surface of the base portion 31 of the blade 3 can be reduced.

Furthermore, in the marine propeller 1, the inner wall surface 212 is inclined in a direction in which the groove width dimension W is widened as it goes radially inward. Therefore, the groove width dimension W on the radially inner side is larger than the groove width dimension W on the vertex 22p of the protruding portion 22 . On the other hand, the outer wall surface 312 is inclined in such a direction that the base portion thickness dimension T increases as it goes radially inward. Therefore, the thickness T of the base portion on the inner side in the radial direction is larger than the thickness T of the base portion at the bottom point 32b of the depressed portion 32 . Therefore, when the base portion 31 of the blade 3 is inserted into the groove portion 21 of the boss 2, the inner wall surface 212 and the outer wall surface 312 are completely in contact with each other without any gap.

This is because the inner wall surface 212 on the side opposite to the tilting direction (the side in the rotating direction of the marine propeller 1) receives the load F3 at a large angle close to vertical. This is also because the outer wall surface 312 receives the load F4 at a large angle close to vertical. In addition, the same technical idea is applied not only to the anti-tilting direction side (rotating direction side of the marine propeller 1) but also to the tilting direction side (anti-rotating direction side of the marine propeller 1). This is because the effect can be obtained regardless of the rotating direction of the propeller 1 for use. However, it may be applied only to the anti-tilting direction side (rotating direction side of the marine propeller 1).

As described above, in the marine propeller 1, the inner wall surface 212 radially inward of the apex 22p of the protruding portion 22 is inclined in the direction of widening the groove width W as it goes radially inward. Further, the outer wall surface 312 radially inward of the bottom point 32b of the depressed portion 32 is inclined in the direction of widening the base portion thickness dimension T as it goes radially inward. Then, the inner wall surface 212 and the outer wall surface 312 are brought into contact with each other. According to the marine propeller 1, even if a load is applied to the radial inner portion (the inner wall surface 212) of the inner wall surface 21s, the stress in the vicinity of the groove portion 21 of the boss 2 can be reduced. Further, even if a load is applied to the radially inner portion (outer wall surface 312) of the outer wall surface 31s, the contact pressure on the surface of the base portion 31 of the blade 3 can be reduced.

Finally, another characteristic portion of the marine propeller 1 will be described with reference to FIGS. 7 and 8, and its effect will be described.

In the marine propeller 1 , the outer edge Pa of the inner wall surface 21 s and the outer edge Pb of the outer wall surface 31 s coincide with each other, and a curved portion 34 is formed from the outer edge Pb of the outer wall surface 31 s and connected to the wing body portion 33 . This can also be said to be a shape found as a result of performing simulations using all kinds of calculation models.

In this way, in the marine propeller 1, the outer edge Pa of the inner wall surface 21s and the outer edge Pb of the outer wall surface 31s are aligned, and the curved portion 34 is formed from the outer edge Pb of the outer wall surface 31s and connected to the wing body portion 33. . According to the marine propeller 1, since the rigidity of the wing body portion 33 is increased, it is possible to suppress the local load from being applied to the inner wall surface 21s and to reliably reduce the stress in the vicinity of the groove portion 21 of the boss 2. Become. Further, since the rigidity of the blade body portion 33 increases, it is possible to suppress the local load from being applied to the outer wall surface 31s, and to reliably reduce the contact pressure on the surface of the base portion 31 of the blade 3.

1 marine propeller 2 boss 21 groove 21s inner wall surface 211 inner wall surface 212 inner wall surface 22 protrusion 22p vertex 3 blade 31 base 31s outer wall surface 311 outer wall surface 312 outer wall surface 32 depressed portion 32b bottom point 33 wing body portion 34 curved portion A rotation Shaft W Groove width T Base thickness Pa Outer edge Pb Outer edge

Claims (4)

a boss having a groove formed on its outer peripheral surface;
a blade having a base formed on one end side,
A marine propeller configured by inserting the base of the blade into the groove of the boss,
a protrusion is provided on the inner wall surface forming the groove of the boss and extends along the insertion direction of the base of the blade;
An outer wall surface constituting the base of the blade is provided with a recessed portion extending along the insertion direction of the base of the blade,
When the base of the blade is inserted into the groove of the boss, the protrusion and the depression are engaged with each other , and
The apex of the protrusion and both slopes thereof and the bottom point of the recessed portion and both slopes thereof are in contact with each other and are fitted so as not to form a gap.
A marine propeller characterized by: the inner wall surface radially outward of the apex of the protrusion is inclined in the direction of widening the groove width dimension toward the radially outer side,
the outer wall surface radially outward of the bottom point of the recessed portion is inclined in a direction in which the thickness of the base increases as it extends radially outward;
2. A marine propeller according to claim 1, wherein said inner wall surface and said outer wall surface are in contact with each other. The inner wall surface radially inner than the vertex of the protrusion is inclined in the direction of widening the groove width dimension as it goes radially inward,
The outer wall surface radially inner than the bottom point of the depressed portion is inclined in a direction in which the thickness of the base increases as it goes radially inward,
3. A marine propeller according to claim 1, wherein said inner wall surface and said outer wall surface are in contact with each other. 4. The outer edge of the inner wall surface and the outer edge of the outer wall surface are aligned with each other, and a curved portion is formed from the outer edge of the outer wall surface and connected to the wing body. 1. A marine propeller according to claim 1.

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