JPS59190092A - Fixing method and structure of vessel propeller - Google Patents

Abstract

PURPOSE:To fix a propeller firmly while to reduce size and to improve the propulsion efficiency by fitting a propeller boss to a fastening rod then fixing temporarily. CONSTITUTION:Hard material such as copper is injected against the contact face 27 of flange 11 and propeller boss 15 to increase the friction factor then the propeller boss 15 is fitted to a fastening rod 12 to fix the propeller temporarily by means of a stopper plate 17 and a nut 16. Then the referential length (L) of the fastening rod 12 is measured to insert a medium through a central hole 14 and heat. Upon confirming of extension of the fastening rod 12 by predetermined amount, the nut 16 is rotated in fastening direction to advance by predetermined amount then said medium is pulled out to cool the entirety. Thereafter rust prevension agent is injected into the central hole 14 while filler is injected into the space 22. Then a packing stopper 20 is fixed to seal the sleeve 26 and flange 11 by means of the packing and bolt.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for attaching a marine propeller to a propeller shaft using a flange method, and a structure for attaching the same. The drawbacks are the difficulty of transmitting high torque, the occurrence of fretting corrosion at the push-in end of the propeller boss, the complexity of propeller sampling inspections during periodic docking inspections, and the propulsion efficiency due to the increase in the size of the propeller boss. The aim is to fundamentally solve problems such as the decline in production costs and the rise in manufacturing costs, thereby achieving safe ship operation and reducing maintenance costs.

Almost all ships are 1/'1 as shown in Figure 1.
Boss cone part (1) with a taper of 2 to 1/12.5
is the y part of the propeller shaft (2) with the same taper (
3) K Mantle 6 The installation is fixed by fitting and pushing.

A key is sometimes provided in the Bonucorn part, but if a key is provided, cracks are likely to occur from the key.
Particularly in recent large ships, keyless systems that do not require a key are becoming commonplace.

Although the propeller mounting method shown in FIG. 1 has many drawbacks as described below, it has been used as it is for a long time because no suitable and reliable alternative mounting method has been developed.

However, this has always been a source of headaches for those involved in shipping.

[Disadvantages due to propeller push-in method]

1); There is a lack of gripping force and transmission torque of the cone part.

That is, since the propeller shaft of the propeller boss (4) is normally pushed in at room temperature, it is difficult to apply a large pushing amount.

In addition, during the periodic docking inspection that is carried out every four years, the propeller is removed and the shaft is inspected for scratches.
90092(2), so the pushing amount must be set to an appropriate amount.

The pushing amount X of the propeller boss is empirically given by equation (1).

X-〒plane τφd ・・・・・・・・・・・・ (IJ where d; propeller shaft diameter; constant determined by boss material Mn For bronze K = 3.0 to 5.0 like this To,
Although the indentation part is broken at a large indentation rate, the Young's modulus E of the copper alloy is 1.
Young's modulus of steel is E2100 at around 2000fvIljIP
It is only about 60% of 0KM1jR2.

Therefore, even when pushing in at a large pushing rate, it is difficult to increase the contact pressure with the propeller shaft, which is necessary to increase the transmitted torque.

Furthermore, as calculated from the equation (2) regarding the expansion of the plastic deformation region of the pushing part, the plastic deformation range reaches 120 to 150% of the propeller shaft diameter, so the propeller is attached to the propeller shaft by the pushing method. In this case, the diameter of the propeller pos is inevitably large.

Expansion of the plastic deformation region generated in the propeller boss push-in portion due to propeller push-in is expressed by equation (2).

However, dp; diameter d of the plastic deformation zone; inner diameter α of the propeller boss; indentation rate E; Young's modulus σy of the propeller boss material; tensile yield point of the propeller boss material now, α-(3,0 to 5.0)/ 10nO, E = 1
If 2000ψ-σy = 25 KV1uR2
dp/P = 1.17 to 1.47.

2); Occurrence of fretting corrosion at the pushed end.

The propeller's ponnu diameter must be made as small as possible to increase propulsion efficiency. Therefore, in order to transmit large torque, the length of the cone section must be increased.

Since the propeller rotates in a cantilever-like shape, repeated bending stress is applied to the propeller shaft due to the propeller's own weight or the effects of waves, etc. near the end of the boss (see symbol (5) in Figure 1). It is unavoidable that small scratches will occur.

This tendency is further exacerbated by the formation of a plastic deformation region on the inner surface of the boss of the propeller push-in portion and by the small Young's modulus of the propeller material. For this reason, cracks due to fretting corrosion are likely to occur near the reference numeral (5) on the propeller shaft side of the boss end, which may result in a major accident such as breakage of the propeller shaft.

In order to prevent this type of accident, ships are docked every four years, the propellers are removed, and the shafts are carefully inspected.
This requires a lot of money and time.

3); It is difficult to fit the cone parts together.

In other words, the cone portion where the propeller boss and propeller shaft contact (
1) In order to ensure torque transmission, after finishing the machine, careful alignment is performed to check the degree of contact. This work requires a large number of skilled workers and is therefore a major drawback in production.

The present invention was devised in view of such a central situation, and the first aspect is to carefully form a central hole in the axial direction from the reference surface of the shaft end of a tightening rod having a flange on the propeller shaft. After forming and temporarily attaching the propeller boss to the tightening rod, measure the standard length of the tightening rod on the reference surface side and at the bottom of the center hole. After confirming that the rod has elongated by the specified amount by heating it, tighten it from the shaft end of the tightening rod.After that, cool the entire rod and measure the standard length to check whether the specified tightening force is applied. The present invention provides a method for attaching a marine propeller, which comprises: confirming the above, and then injecting a rust preventive agent into the center hole, closing the hole, and then closing the flange completely and attaching the propeller boss to the propeller shaft. be.

Second, in the present invention, a bottomed center hole is formed in the axial center of the tightening rod of the propeller shaft having seven flange in the middle in the axial direction from the shaft end, and the tightening rod is fitted into the center hole. The propeller post is pressed against the flange via a nut screwed onto the shaft end side of the tightening rod, and
) It is attached via a bolt inserted into the lunge, and
The present invention provides a mounting structure for a marine propeller, characterized in that a rust preventive agent is injected into the center hole and a lid is provided for closing the shaft end side of the center hole.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

In FIG. 2, 00 is a propeller shaft, and a tightening rod having a flange (11) in the middle is formed at one end thereof.

A bottomed center hole a4 is formed in the tightening rod 02 on the axial center from a reference surface a3 at the end of the shaft in the axial direction.

α9 is the propeller boss, which is fitted onto the tightening rod (c).
A nut αQ is screwed into the threaded part formed on the outer periphery of the shaft end of the tightening rod (2), and the propeller boss α9 is pressed against the flange 0]) via the holding plate a″I).
The spigot part 08) of the 7 lange 0] is fitted with the spigot on the outer circumferential surface of the 7 lange 0], and the seal holder (A) is attached with a plurality of presser bolts 1) under the seal 09 interposed therebetween. , Here, the propeller boss 09 is attached to the propeller shaft OQ.

Furthermore, a rust preventive agent is injected into the center hole 04), a filler is injected into the space (a), and a seal (to) is interposed on the reference plane 0] side, and the lid C◆ is injected with a plurality of bolts. The central hole 04 is closed.

In addition, in FIG. 2, (c) indicates a seal or packing, and (c) indicates a sleeve.

To explain the installation method, a hard material such as 130R steel is melted for (A) between the flanges all and the propeller boss 09, and the friction between the flange 01) and the propeller boss 0θ is After increasing the coefficient, propeller boss α9
into the tightening rod 0'2, and then tighten the presser plate 0η and the nut (
161 to temporarily attach the propeller.

In this case, if a hard material such as 15Cr steel is thermally sprayed on both sides of the holding plate Oη, it will be effective to increase the transmitted torque and prevent the nut Oe from loosening.

Next, the reference length L of the tightening rod 0 is measured between the reference surface (13 side and the hole bottom (14A) side of the center hole 04), and a heating medium such as a heater is installed in the center hole 04). Insert tightening rod O
Heat z.

1Q After confirming that the tightening rod has been extended by a predetermined amount, the nut αQ is turned in the tightening direction to move it forward by a predetermined amount, the heating medium is withdrawn, and the whole is cooled. After cooling, the reference dimensions are measured and the presence or absence of a predetermined tightening force is confirmed.

This propeller tightening force test is performed using a reference length L.

Next, a rust preventive agent is injected into the central hole α, which is sealed with a lid (C) and a seal (C), and a filler is injected into the space (A).

Attach the gasket retainer and seal the sleeve (c) and flange αD with the gasket a0 (c) and presser bolt 0).

The holding bolt Q°C is screwed into the post αS and has a secondary attachment function for the propeller and 7 langes.

In other words, the propeller has a tightening rod (a) and an auxiliary holding rod) 61! Since it is attached to the propeller shaft αq by I), loosening or slipping of the propeller during operation is unlikely to occur.

The flaw inspection of the propeller shaft 00 is carried out by removing the lid (C) and using the ultrasonic flaw detection method or the like through the center hole (141). It is preferable to extend it.

The present invention has been described above, and will be explained in more detail as follows.

<Regarding the trial calculation of the required propeller shaft diameter> According to the Nippon Kaiji Kyokai Steel Ship Rules, the minimum shaft diameter do of the intermediate shaft is specified by formula (3).

■：Shaft output at continuous maximum engine output (P8) 几：
The rotational speed (rpm) of the intermediate shaft at the time of continuous maximum output of the engine.

H in formula (3) is expressed by formula (4).

Equations (5) and (6) can be changed from equations (3) and (4).

JP-A-59-190092 (4) T, = d03...
(6) However, T: rotational torque of the shaft at the continuous maximum output of the engine (Kyf) The maximum shaft diameter d3 of the propeller shaft is defined by equation (7).

P: Outer diameter of propeller (vR) C: Constant that depends on the type of propeller Generally d and d
Since the dimensional relationship of , is approximately equal to equation (8), d@= 1.
2~t3do ・−・・−(sl Here, ds =
Let us take the value of j3·do.

FIG. 3 shows the vicinity of the propeller attachment part, and in FIG. 3, ds: propeller shaft diameter dl: center hole diameter &16 d2: tightening rod diameter dJ: flange diameter.

The transmission torque T1 of the propeller post by the flange is expressed by the formula (9
).

Therefore, T'= 'μ・(d3+d2)・(dJ2 dJ)
・cr Now, dm=d2, d3=αeda, da
=1.3"do,"="n・μ・(α+1)
(α2-1)・dJ・σ= 0.862・μ・(α+
1) (α2-1)・dJ・σ・・・・・・・・・ Oo
However, μ: Coefficient of friction between propeller flange σ: Load per unit area of propeller flange contact surface (KyfArm) When formula (6) and formula Oq are used, formula (1) can be changed.

μ ・ (α+1) (α2−1) fist σ = 1.16
0 ......The αD formula OB can be said to be a relational formula that provides 14 necessary conditions for transmitting the rotational torque from the engine via the intermediate shaft to the propeller post. At this time, the stress σ1 generated in the tightening rod is expressed by equation 03 from the following relationship.

−・(ds2di2)・σ−j・(d, 2” dI”
)・Goo However, mountain = α・d2, dI = 0.4・
d2. The relationship between dx = d, m formula an, and 202 can be illustrated as shown in Figure 4 m (21).

From FIG. 4 (1) and (2), the load stress σ1 on the tightening rod decreases as the friction coefficient μ between the propeller post and the flange increases, but it does not change much depending on the ratio α of the propeller post diameter/propeller shaft diameter. 0- used in propeller pos.
The coefficient of friction between bronze and the steel used for the propeller shaft is 0.1
It is 0 to 0.15.

Also, α of the integral propeller is approximately 2.0, so α=
1.8, assuming μ = 0.1 and calculating the stresses σ and σ1 that must be applied to the propeller post and tightening rod from Fig.
becomes.

A15 These stresses cannot be considered to be high values compared to the strength of the materials that constitute the propeller boss and propeller shaft metal.

After spraying a hard material such as 13Or copper on the flange surface and tightening the propeller boss to that surface, the friction coefficient μi between the two increases to 0.6 to 0.8. Now, considering safety, if we set μ-〇4 and tighten the propeller boss to the 7th flange with the same stress, the ratio α of propeller post diameter/propeller shaft diameter will be about 1.55, as shown at point A in No. 41'l (]). ,
It can be seen that sufficient rotation and rotational torque can be transmitted to the propeller even if the propeller boss diameter is extremely small.

The weight of the propeller boss accounts for about 40% of the total propeller weight.

1. When the center hole diameter of the propeller boss is -iD, and when the outside diameter of the hoss changes from 1.8D to 1.35D, the 1 generation weight reduced small bamboo is tested as follows: ((1,35・D)2 -1γ)/l(1,80・D)2
-1121 = 0.37, which means a weight reduction of about 60%.

This reduction amount is approximately 24% relative to the propeller vertical surface.

Holding opening U39-190092 (5) The above trial calculation uses the flange method of the present invention, and the effect is even greater when the friction coefficient between the propeller boss and the flange is 0.10 to 0.4.

In the case of the conventional method, the boss outer diameter is approximately 2. Od, (where ds is the propeller shaft diameter). The boss length is 2. for torque transmission.
It will be about 5.

In case of flange method 1. Since torque transmission and boss length are unrelated, a boss length of 1.5D is sufficient.

Therefore, as below ((1,55・D)2-hi)・1.5・city/ ((2,
0・D)2−D')・2.5・city=0.16, and it is expected that the weight will be reduced by 80% compared to the propeller post, and the amount will be reduced by 62% compared to the total weight of the propeller.

Conventionally, it has been known that propeller bosses have a margin for operating stress from propeller blades.

However, when using the push-in method, it was not possible to reduce the size of the propeller boss in terms of torque transmission.

17 In this regard, by applying the friction coefficient increasing method using hard material thermal spraying to the flange mounting method of the present invention, it is possible to downsize the propeller boss to the required dimensions for operation, which not only reduces costs due to weight reduction, but also reduces the propeller boss's size. This can be useful for optimizing the stern shape and improving propulsion efficiency by reducing weight and reducing the propeller boss diameter.

In Fig. 2, a hard material such as 130R steel is sprayed directly onto the flange (A), but instead of this, a thin hollow disc with hard material sprayed on both sides is used to attach the flange 0 and the propeller post aυ. The same effect can be obtained even if it is inserted between the two, and in any case, it is effective if the thickness of the wound is 25 μm, but for practical purposes it needs to be about 50 μm or more.

Next, the inadequacies of the conventional push-in propeller mounting method will be explained in detail, and then the effects of the present invention will be discussed.

Propellers used in seawater are often made of D-bronze due to its corrosion resistance.

Since Ag-bronze is a material that is usually used as a bearing material, it has a small friction coefficient with copper-based materials, and also has a &18 Young's modulus smaller than that of steel.

This is a woody defect in the push-in propeller installation method.

In other words, the relationship between the expansion of the plastic deformation region that occurs in the propeller post due to pushing and the increase in contact surface pressure is as follows: When the propeller is pushed beyond the elastic region, the relationship between the contact surface pressure and the plastic deformation region is 2αJ. be done.

However, P! : Contact pressure of the pushing surface σy: Tensile yield point ds of the material: Propeller shaft diameter dB: Prober boss outer diameter dP: Diameter of plastic deformation zone dn=2・City If we calculate the relationship between P+/cry and dP from equation α3, It will look like Figure 5.

FIG. 5 also shows the degree of expansion of the plastic deformation region generated near the propeller boss pushing surface due to propeller pushing determined from equations (1) and (2).

As is clear from Fig. 5, even if the propeller is pushed in at a high rate reaching 19,050% of the propeller post wall thickness, the increase in contact surface pressure is about 50% of that under the elastic condition.
This is only a % increase, and even though a large stress is applied to the propeller post, the increase in contact surface pressure is small.

This and Steel-A, l! /If you consider that the coefficient of friction of bronze rll+ is small, you can understand the absurdity of attaching the propeller using the push-in method.

Regarding the low Young's modulus of bronze, the contact pressure P under elastic conditions when the shaft member A is pushed into the cylinder B shown in FIG. 6 is expressed by the formula α4).

However, r,, r3: Inner and outer radius EA of the pushing part
,] Tsumugi: Young's modulus of A and B materials ■mu, VB: Poisson's ratio of A and B materials δ: Radial rotation pushing distance r3-2・r2, equation 04) is rewritten as 2α9 It will be done.

Special opening H59-1901)! 12 (6) Shaft, shaft material A is 'Hd (EA = 210001φ7vaP)
and B material is steel (E-row 21000 I9Δvts2)
and 2 of 0 bronze (En = 12000 KZAd)
Assuming that the glaze is the same and the indentation conditions are the same, the ratio of the contact surface pressures Pos+ (steel) and PoAe (AA bronze) is calculated as P. st
/PoAt==1.55.

From this result, if a material with a large Young's modulus E is used for the boss material, as mentioned above, it is possible to provide sufficient contact surface pressure without pushing the propeller at a rate so large that the boss material is plastically deformed. can.

Furthermore, considering that the steel-to-steel friction coefficient μ is about 0.25, it is considered that sufficient rotational torque can be given to the propeller at a pushing rate within the elastic range.

In this way, A! Attaching the bronze propeller to the propeller shaft using a push-in method is inappropriate and can be said to be unreliable.

As described above in detail, the flange type propeller mounting method and its mounting structure of the present invention have the following advantages.

(1) The propeller post can be made smaller, improving propulsion efficiency by 2
1, the weight of the propeller is reduced, the shape of the stern section can be rationalized, and the cost of the propeller itself can be reduced.

(2) The safety of the shaft system is improved because there are no fretting corrosion points in the propeller shaft system. (3) The propeller mounting part can be inspected non-destructively without removing the propeller. The periodic inspection process will be reduced.

(4) During the work of attaching the propeller to the propeller shaft, the degree of fixation of the propeller is quantitatively measured and guaranteed.

Further, since the degree of propeller tightening can be checked at the time of docking without removing the propeller, periodic inspection of the propeller is simplified.

(5) Manual finishing processes such as rubbing in the manufacturing process are greatly reduced.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing a conventional mounting structure, Fig. 2 is a sectional view showing an example of the present invention, Fig. 3 is a detailed sectional view of the vicinity of the tightening rod, and Fig. 4 (1) is a negative view of the propeller post. 22 -1-\) 1-o-2+ Graph showing the load stress, Figure 4 (2) is a graph showing the load stress of the tightening rod, Figure 5 is the contact surface pressure and plasticity of the pushing part of the conventional example FIG. 6, which is a graph of the relationship between the expansion of the deformation region and the expansion of the deformation region, is an explanatory diagram showing the contact surface pressure, etc. in the elastic conditions when the cylindrical material (boss) and the shaft material (propeller shaft) are pushed together. (10... propeller shaft, αυ... flange, O2...
... Tightening rod, (13... Reference surface, α Yu... Center hole,
09...Propeller post, OQ...Natsuto, Ql)・
...Bolt (Foundation)...Lid.

Claims (1)

[Claims] A center hole is formed in the axial center of a tightening rod having a flange on the 1st and 10th axis in the axial direction from the reference surface of the shaft end, and a propeller boss is fitted into the tightening rod. and temporarily install it,
Measure the reference length of the tightening rod between the reference surface side and the bottom side of the center hole, then heat the tightening rod and confirm that the rod has expanded by a predetermined amount, and then tighten the tightening rod. Tighten from the shaft end side, then cool down the whole, measure the reference length and check whether the specified tightening force is present, then inject rust preventive into the center hole and close the hole, A method for attaching a marine propeller, comprising attaching a propeller boss to a propeller shaft via the flange. 2. A bottomed central hole is formed in the axial center of the tightening rod of the propeller shaft having a flange in the middle, extending from the shaft end in the axial direction,
A propeller boss 2 fitted onto the tightening rod is pressed against the flange via a nut screwed onto the shaft end side of the tightening rod, and is attached via a bolt inserted into the flange, and further, A mounting structure for a marine propeller, characterized in that a rust preventive agent is injected into the center hole and a lid is provided to close the shaft end side of the center hole.