LU502771B1

LU502771B1 - Sealing protection structure for stern sealing end of oar-engine

Info

Publication number: LU502771B1
Application number: LU502771A
Authority: LU
Inventors: Jianli Zheng; Shanshan Wu; Yuantao Chen; Fei Fan; Shengyong Li; Shichun Yuan
Original assignee: Fishery Machinery & Instrument Res Inst Cafs
Priority date: 2022-03-11
Filing date: 2022-09-08
Publication date: 2023-03-08
Also published as: CN217416031U

Abstract

The present invention relates to a sealing protection structure for a stern sealing end of an oar-engine. The sealing protection structure includes a stern shaft, a shaft sleeve, an end cover, and a bearing, and further includes an inner baffle and an outer baffle. A labyrinth sealing apparatus is arranged in space between the shaft sleeve and the end cover, a first axial gap is formed between the labyrinth sealing apparatus and an outermost end of an inner portion of the end cover, the outer baffle sleeved outside the stern shaft is tightly arranged in the first axial gap, and a first radial gap is formed between the outer baffle and the stern shaft; a second axial gap is formed between an end portion of the shaft sleeve and the outer baffle; the inner baffle is sleeved outside the stern shaft and is in interference fit with the stern shaft; a third axial gap is formed between the outer baffle and a lateral direction of the inner baffle; a second radial gap is formed between the outer baffle and a radial direction of the inner baffle; and the second radial gap, the third axial gap, and the first radial gap form a Z-shape on a cross section.

Description

TT SEALING PROTECTION STRUCTURE FORSTERNSEALINGENDOR nn

OAR-ENGINE

BACKGROUND OF THE INVENTION

[0001] 1. Technical Field

[0002] The present invention relates to a sealing protection structure of a stern sealing end of an oar-engine, and belongs to the technical field of oil-leak-proof sealing for an oar-engine for a fishing boat.

[0003] 2. Description of Related Art

[0004] At present, there are a large number of agricultural oar-engine fishing boats, which are economical and applicable, and it is unrealistic to eliminate them all. The modification of oar-engine sealing is an economical and effective solution to an oil leakage of an oar-engine for a fishing boat.

[0005] Most of propulsion apparatuses of agricultural oar-engine fishing boats are composed of a single cylinder diesel engine, an oar-engine, and a propeller. The oar-engine is generally composed of an upper box, a lower box, and a coupling shaft tube.

The leaked oil of the diesel engine on a deck and external leaked oil of the upper box of the oar-engine seem to seriously pollute the water environment, but an actual leakage amount is very limited; and about 5 kg per year of leakage of each set of the diesel engine and the oar-engine is mainly caused by leakage of a stern shaft seal of the lower box of the oar-engine due to damage caused by the propeller winding foreign matters, which pollutes waters and increases use and maintenance costs of fishermen.

[0006] In the prior art, regarding oil pollution prevention measures for diesel engines and oar-engine, the prior art has carried out comparative tests on oil absorption capability of various types of oil absorption felts, and proposed that the use of hard wool 1 problem of collecting leaked oil of diesel engines. Self-made air-permeable components of an upper cover plate of the upper box of the oar-engine are relatively high in modification cost, and the modification cannot solve the problem of oil rising during carrying, which is not conducive to practical application.

[0007] In the prior art, as shown in FIG. 1, the stern shaft seal of the oar-engine is a contact seal composed of two rubber oil seals 4 and one rubber water seal 3. The oil seal 4 and the water seal 3 tightly match a shaft sleeve 2 and an end cover 5 in a radial direction, and tightly match the end cover 5 in an axial direction to form axial and radial seals. In order to protect the water seal and the oil seal of the stern shaft, on the premise that an original shaft and a transmission system are unchanged, a labyrinth seal is arranged at an outer end of the water seal 3 close to an inner wall of the end cover to prevent the foreign matters from entering the lower box. The sealing of a bearing may prevent dust, water, or other foreign matters from intruding into the bearing, and may further reduce leakage of lubricant. When selecting a bearing sealing apparatus, a single sealing structure may be used or a combined form may be used according to bearing operating conditions and environments. As shown in FIG. 1, under a normal operating condition, two rubber oil seals 4 and one rubber water seal 3 may ensure that water cannot enter the lower box, and lubricating oil cannot permeate into the waters. However, since the stern shaft runs for a long time, the oil seal 4 and the water seal 3 may be gradually aged and worn, the thickness of the shaft sleeve 2 is also reduced due to abrasion, the sealing performance is damaged, and water permeates into the lower box under a thrust action of the propeller when the propeller is in operation. The lower box is communicated with the upper box, such that oil may continuously flow out from an air hole of the cover plate of the upper box, and when the operation is stopped, the oil slowly and continuously flows out from the 2 plastic wastes, and even iron wires are wound on the propeller, the stress of the stern shaft is increased, the abrasion of the shaft, the oil seal, and the water seal is increased, the noise of the diesel engine is increased, rotating speed is reduced, even the diesel engine is stopped, and at the moment, the diesel engine needs to be stopped to clean wound matters.

Suppose a foreign matter such as a small fishing net is wound. In that case, the foreign matter easily enters the end cover 5 through a gap to reach the water seal 3 under action of rotating force of the propeller, such that the water seal 3 and the oil seal 4 are damaged due to stress, and lubricating oil leaks into the water. Therefore, reasonable measures should be taken to solve it.

BRIEF SUMMARY OF THE INVENTION

[0008] The present invention aims at providing a sealing protection structure for a stern sealing end of an oar-engine, which is improved on an existing sealing protection structure for a stern sealing end of an oar-engine by adding an inner baffle and an outer baffle, to solve an oil pollution problem of agricultural oar-engine fishing boats with low-cost technical innovation.

[0009] The present invention uses the following technical solutions:

[0010] a sealing protection structure for a stern sealing end of an oar-engine, including a stern shaft 1, a shaft sleeve 2, an end cover 5, and a bearing 6, and further including an outer baffle 7 and an inner baffle 8. A labyrinth sealing apparatus is arranged in space between the shaft sleeve 2 and the end cover 5, a first axial gap is formed between the labyrinth sealing apparatus and an outermost end of an inner portion of the end cover 5, the inner baffle 8 sleeved outside the stern shaft 1 is tightly arranged in the first axial gap, and a first radial gap is formed between the inner baffle 8 and the stern 3

-_ LU502771 shaft 1; a second axial gap is formed between an end portion of the shaft sleeve 2 and the inner baffle 8; the outer baffle 7 is sleeved outside the stern shaft 1 and is in interference fit with the stern shaft 1; a third axial gap is formed between the inner baffle 8 and a lateral direction of the outer baffle 7; a second radial gap is formed between the inner baffle 8 and a radial direction of the outer baffle 7; and the second radial gap, the third axial gap, and the first radial gap form a Z-shape on a cross section.

[0011] Preferably, the labyrinth sealing apparatus comprises a rubber oil seal 4 and a rubber water seal 3 arranged transversely at an interval.

[0012] Preferably, the shaft sleeve 2 has a diameter of 44 mm and a length of 29 mm.

[0013] Preferably, a second rubber water seal used to protect the rubber water seal 3 and the rubber oil seal 4 is formed outside the rubber water seal 3.

[0014] Further, a sum of an axial length of the rubber water seal 3, the rubber oil seal 4, and the second rubber water seal is 30 mm, which is 1 mm longer than the axial length of the shaft sleeve 2.

[0015] Preferably, the inner baffle 8 is made of steel and has an outer diameter of 62 mm.

[0016] Preferably, the first radial gap is 0.10-0.15 mm; and a sum of the thickness of the second rubber water seal and the inner baffle 8 is 7.75 mm.

[0017] Preferably, the outer baffle 7 has an outer diameter of 44 mm, an inner diameter of 29.9 mm, and a thickness of 8 mm; and the third axial gap is 1-2 mm.

[0018] Preferably, the third axial gap is 43 mm.

[0019] The beneficial effects of the present invention lie in that: the possibility that smaller foreign matters enter the water seal to cause damage to the water seal and the oil seal is reduced, large foreign matters may be blocked by the outer baffle 7, small 4

_ LU502771 foreign matters are blocked by the inner baffle 8, smaller foreign matters lose the capability of destruction after entering a labyrinth formed by 4 cavities that are communicated with each other, and the foreign bodies basically cannot cause substantial damage to the water seal under the protection of the labyrinth apparatus except for special conditions. Therefore the problem of oil leakage is fundamentally solved.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0020] FIG. 1 is a schematic diagram of a sealing protection structure for a stern sealing end of an oar-engine in the prior art (an output end of a stern shaft of a lower box of a 12 hp oar-engine); and

[0021] FIG. 2 is a schematic diagram of a sealing protection structure for a stern sealing end of an oar-engine of the present invention (an output end of a stern shaft of a lower box of a 12 hp oar-engine).

[0022] In the figures, 1. stern shaft, 2. shaft sleeve, 3. rubber water seal, 4. rubber oil seal, 5. end cover, 6. bearing, 7. outer baffle, and 8. inner baffle.

DETAILED DESCRIPTION OF THE INVENTION

[0023] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0024] Embodiment 1 (comparative embodiment):

[0025] The existing design is shown in FIG. 1, a stern shaft seal of a 12 hp oar-engine is a contact seal composed of two rubber oil seals 4 having a thickness of 10 mm and one rubber water seal 3 having a thickness of 5 mm, where an outer diameter of the oil seal 4 and the water seal 3 is 62 mm. A stern shaft 1 has a basic diameter of 30 mm, and a shaft sleeve 2 has a diameter of 44 mm and a length of 36 mm. An end cover 5 of an

Tutput end of à sem shaft of à Tower box of the oarengine has an aperture of 46 mm. Tue | oo oil seal 4 and the water seal 3 tightly match a shaft sleeve 2 and an end cover 5 in a radial direction, and tightly match the end cover 5 in an axial direction to form axial and radial seals. In order to protect the water seal and the oil seal of the stern shaft, on the premise that an original shaft and a transmission system are unchanged, a labyrinth seal is arranged at an outer end of the water seal 3 close to an inner wall of the end cover to prevent the foreign matters from entering the lower box. Sealing of a bearing may prevent dust, water, or other foreign matters from intruding into the bearing, and may further reduce leakage of lubricant. When selecting a bearing sealing apparatus, a single sealing structure may be used or a combined form may be used according to bearing operating conditions and environments. In FIG. 1, the thickness of the end cover 5 is about 15 mm, and a gap between the end cover 5 and a propeller is about 6-9 mm. The propeller in FIG.1 is a cast iron propeller, but an end portion of the end cover 5 actually used now has a thickness of 8 mm, a distance from the oil seal 4 to an outer edge of the end cover 5 is equal to the length of the original shaft sleeve 2, that is, 36 mm, and an actual gap between a propeller hub and the end cover 5 is 13-16 mm, which leaves space for adding a labyrinth apparatus.

Under a normal operating condition, two rubber oil seals 4 and one rubber water seal 3 may ensure that water cannot enter the lower box, and lubricating oil cannot permeate into the waters. However, since the stern shaft runs for a long time, the oil seal 4 and the water seal 3 may be gradually aged and worn, the thickness of the shaft sleeve 2 is also reduced due to abrasion, the sealing performance is damaged, and water permeates into the lower box under a thrust action of the propeller when the propeller is in operation. The lower box is communicated with an upper box, such that oil may continuously flow out from an air hole of an cover plate of the upper box, and when the operation is stopped, the oil slowly and continuously flows out from the water near the lower box. When the foreign 6

-_ LU502771 matters such as waterweeds, fishing nets, plastic wastes, and even iron wires are wound on the propeller, the stress of the stern shaft is increased, the abrasion of the shaft, the oil seal, and the water seal is increased, the noise of the diesel engine is increased, rotating speed is reduced, even the diesel engine is stopped, and at the moment, the diesel engine needs to be stopped to clean wound matters. Suppose a foreign matter such as a small fishing net is wound, the end cover 5 of the lower box has an aperture of 46 mm, the shaft sleeve 2 has an outer diameter of 44 mm, and a radial gap thereof is 1 mm after being assembled, while a thread of the fishing net is generally about 0.30 mm. In that case, the thread of the fishing net easily enters the end cover 5 through a gap to reach the water seal 3 under action of rotating force of the propeller, such that the water seal 3 and the oil seal 4 are damaged due to stress, and lubricating oil leaks into the water. Therefore, reasonable measures should be taken to solve it.

[0026] Embodiment 2

[0027] This embodiment elaborates improvements of the labyrinth sealing protection apparatus arranged at a stern shaft rubber seal and the end cover of the lower box of the 12 hp agricultural oar-engine, and other types of agricultural oar-engine may be popularized and applied by referring to the improved technology, so that oil pollution of the agricultural oar-engine fishing boat is reduced.

[0028] A layout of the entire system is shown in FIG. 2 (sectional view).

[0029] On the basis of FIG. 1, an inner baffle 8 and an outer baffle 7 are additionally arranged outside the original stern shaft seal in FIG. 2, and form a labyrinth together with a shaft sleeve, a shaft, a water seal, the end cover, and the like, so that a stern shaft sealing apparatus is protected, and the original single contact seal is changed into a combined form of a contact seal and a non-contact labyrinth seal.

[0030] 1) A setting of the inner baffle: 7

-_ LU502771

[0031] as shown in FIG. 2, the original diameter of 44 mm of the shaft sleeve 2 is not changed, and the length is reduced from 36 mm to 29 mm in the box. A rubber water seal 3 having a thickness of 5 mm is added outside the original water seal 3 to protect the original oil seal and the water seal. A sum of an axial length of the oil seal 4 and the water seal 3 is 30 mm, which is 1 mm longer than the axial length of the shaft sleeve 2. A steel inner baffle 8 (not directly contacted with the shaft 1 and the shaft sleeve 2) having a thickness of about 2.75 mm, an inner aperture of 30.20-30.30 mm, and an outer diameter of 62 mm is additionally arranged outside the newly added water seal 3. The inner baffle 8 and the stern shaft 1 form a radial gap of 0.10-0.15 mm. The inner baffle 8 is mainly used to directly block invasion of the small foreign matters such as the thread of the fishing net, and the water seal is not directly stressed, thereby directly protecting the water seal and the oil seal. A sum of the thickness of the newly added water seal 3 and the newly added inner baffle 8 is about 7.75 mm, so the original end cover cannot accommodate a modified shaft sealing apparatus, and the depth of the end cover is increased by nearly 8 mm at a place to be sealed. This modification plan requires additional casting and processing of the end cover.

[0032] 2) A setting of the outer baffle:

[0033] as shown in figure 2, in order to prevent the inner baffle 8 from being damaged due to direct contact with the large foreign matters, the outer baffle 7 (rotating together with the shaft, the thickness may be properly reduced according to an actual situation, and is in interference fit with the shaft when assembled) having an outer diameter of 44 mm, an inner diameter of about 29.9 mm, and a thickness of 8 mm is arranged at a vertebral body part of the shaft, and a gap of 1-2 mm is reserved between the outer baffle 7 and the inner baffle 8, so that the inner baffle 8 and the outer baffle 7 are prevented from being in direct contact and being rubbed. A distance from the oil seal 4, 8

ZN LU502771 the water seal 3, and the inner baffle 8 to the outer edge of the outer baffle 7 (1-2 mm higher than the outer edge of the end cover 5) is about 43 mm, and compared with the axial length of 36 mm from the original oil seal 4 to the end cover 5, the length is increased by nearly 7 mm, namely the gap between the propeller hub and the outer baffle 7 is 7 mm less than that before modification, but an actual gap after modification still reaches an original design gap of 6-9 mm, and installation and operation of the propeller are not influenced.

[0034] The advantages of the present invention lie in that: the possibility that smaller foreign matters enter the water seal to cause damage to the water seal and the oil seal is reduced, large foreign matters may be blocked by the outer baffle 7, small foreign matters are blocked by the inner baffle 8, smaller foreign matters lose the capability of destruction after entering a labyrinth formed by 4 cavities that are communicated with each other, and the foreign bodies basically cannot cause substantial damage to the water seal under the protection of the labyrinth apparatus except for special conditions.

[0035] As shown in FIG. 2, four chambers constituting the labyrinth are illustrated in sequence from outside to inside: 1) a chamber 1 is formed by a radial gap of 1 mm and an axial gap of 7 mm that are formed by the outer baffle 7 and the end cover 5; 2) a chamber 2 is formed by an axial gap of 1-2 mm that is formed by the outer baffle 7 and the inner baffle 8, and a radial gap of 8 mm that is formed by the shaft 1 and the end cover 5; 3) a chamber 3 is formed by an axial gap of about 2.75 mm and a radial gap of 0.10-0.15 mm that is formed between the inner baffle 8 and the shaft sleeve 2; 4) a chamber 4 is formed by a radial gap of 7mm that is formed by the newly added water seal 3 and the shaft sleeve 2, and an axial gap of 1 mm that is formed by a shortened shaft sleeve 2 and the inner baffle 8. The four chambers are communicated with each other to form a labyrinth. The chamber 1 and the chamber 2 prevent foreign matters having a 9

Tamoter of more (han 1 mm from entering the chamber 3 and {he chamber 4, and he oo chamber 3 mainly prevents foreign matters having a diameter of more than 0.2 mm from entering the chamber 4; even if a foreign matter of smaller than 0.2 mm enters the chamber 4, the foreign matter can be hardly contacted with the newly added water seal 3, but the diameter of the foreign matter is too small, and the capability of destruction to the newly added water seal 3 is almost lost after bending of the four chambers. The designed labyrinth sealing apparatus reduces the possibility of water seal and oil seal damage caused by smaller foreign matters entering the water seal, and may also reduce lubricating oil leakage when the water seal and the oil seal are damaged, to buy time for returning to a port for maintenance.

[0036] The above is the preferred embodiment of the present invention, and those skilled in the art can make various changes or improvements without departing from the general concept of the present invention, and all such changes or improvements should fall within the scope of the present invention.

Claims

ZN LU502771 What is claimed is:

1. A sealing protection structure for a stern sealing end of an oar-engine, the sealing protection structure comprising a stern shaft (1), a shaft sleeve (2), an end cover (5), and a bearing (6), and characterized in that: the sealing protection structure further comprising an outer baffle (7) and an inner baffle (8); a labyrinth sealing apparatus being arranged in space between the shaft sleeve (2) and the end cover (5), a first axial gap being formed between the labyrinth sealing apparatus and an outermost end of an inner portion of the end cover (5), the inner baffle (8) sleeved outside the stern shaft (1) being tightly arranged in the first axial gap, and a first radial gap being formed between the inner baffle (8) and the stern shaft (1); a second axial gap being formed between an end portion of the shaft sleeve (2) and the inner baffle (8); the outer baffle (7) being sleeved outside the stern shaft (1) and being in interference fit with the stern shaft (1); a third axial gap being formed between the inner baffle (8) and a lateral direction of the outer baffle (7); a second radial gap being formed between the inner baffle (8) and a radial direction of the outer baffle (7); and the second radial gap, the third axial gap, and the first radial gap forming a Z-shape on a cross section.

2. The sealing protection structure for a stern sealing end of an oar-engine according to claim 1, characterized in that the labyrinth sealing apparatus comprises a rubber oil seal (4) and a rubber water seal (3) arranged transversely at an interval.

3. The sealing protection structure for a stern sealing end of an oar-engine according to claim 1, characterized in that the shaft sleeve (2) has a diameter of 44 mm and a length of 29 mm. 11

-_ LU502771

4. The sealing protection structure for a stern sealing end of an oar-engine according to claim 1, characterized in that the outer side of the rubber water seal (3) forms a second rubber water seal used to protect the rubber water seal (3) and the rubber oil seal (4).

5. The sealing protection structure for a stern sealing end of an oar-engine according to claim 4, characterized in that a sum of an axial length of the rubber water seal (3), the rubber oil seal (4), and the second rubber water seal is 30 mm, which is 1 mm longer than the axial length of the shaft sleeve (2).

6. The sealing protection structure for a stern sealing end of an oar-engine according to claim 1, characterized in that the inner baffle (8) is made of steel and has an outer diameter of 62 mm.

7. The sealing protection structure for a stern sealing end of an oar-engine according to claim 1, characterized in that the first radial gap is 0.10-0.15 mm; and a sum of the thickness of the second rubber water seal and the inner baffle (8) is 7.75 mm.

8. The sealing protection structure for a stern sealing end of an oar-engine according to claim 1, characterized in that the outer baffle (7) has an outer diameter of 44 mm, an inner diameter of 29.9 mm, and a thickness of 8 mm; and the third axial gap is 1-2 mm.

9. The sealing protection structure for a stern sealing end of an oar-engine according to claim 1, characterized in that the third axial gap is 43 mm. 12

REVENDICATIONS

1. Structure de protection d’étanchéité pour une extrémité d’étanchéité de poupe d’un moteur de rame, la structure de protection d’étanchéité comprenant un arbre de poupe (1), un manchon d’arbre (2), un recouvrement d’extrémité (5) et un palier (6), et caractérisée en ce que : la structure de protection d’étanchéité comprenant en outre un déflecteur extérieur (7) et un déflecteur intérieur (8) ; un appareil d’étanchéité en labyrinthe étant agencé dans un espace entre le manchon d’arbre (2) et le recouvrement d’extrémité (5), un premier espacement axial étant formé entre 1’appareil d’étanchéité en labyrinthe et une extrémité la plus extérieure d’une partie intérieure du recouvrement d’extrémité (5), le déflecteur intérieur (8) emmanché à l’extérieur de l’arbre de poupe (1) étant agencé étroitement dans le premier espacement axial, et un premier espacement radial étant formé entre le déflecteur intérieur (8) et l’arbre de poupe (1) ; un deuxième espacement axial étant formé entre une partie d’ extrémité du manchon d’arbre (2) et le déflecteur intérieur (8) ; le déflecteur extérieur (7) étant emmanché a l’extérieur de l’arbre de poupe (1) et étant en ajustement serré avec l’arbre de poupe (1) ; un troisième espacement axial étant formé entre le déflecteur intérieur (8) et une direction laterale du déflecteur extérieur (7) ; un deuxième espacement radial étant formé entre le déflecteur intérieur (8) et une direction radiale du déflecteur extérieur (7) ; et le deuxième espacement radial, le troisième espacement axial et le premier espacement radial formant une forme en Z sur une coupe transversale.

2. Structure de protection d’étanchéité pour une extrémité d’étanchéité de poupe d’un moteur de rame selon la revendication 1, caractérisée en ce que l’appareil d’étanchéité en labyrinthe comprend un joint d’huile en caoutchouc (4) et un Joint d’eau en caoutchouc (3) agencés transversalement à un intervalle.

3. Structure de protection d’étanchéité pour une extrémité d’étanchéité de poupe d’un moteur de rame selon la revendication 1, caractérisée en ce que le manchon d’arbre (2) présente un diamètre de 44 mm et une longueur de 29 mm.

4. Structure de protection d’étanchéité pour une extrémité d’étanchéité de poupe d’un moteur de rame selon la revendication 1, caractérisée en ce que le côté extérieur du joint d’eau en caoutchouc (3) forme un deuxième joint d’eau en caoutchouc utilisé pour protéger le joint d’eau en caoutchouc (3) et le joint d’huile en caoutchouc (4).

5. Structure de protection d’étanchéité pour une extrémité d’étanchéité de poupe d’un moteur de rame selon la revendication 4, caractérisée en ce qu’une somme d’une longueur axiale du joint d’eau en caoutchouc (3), du joint d’huile en caoutchouc (4) et du deuxième joint d’eau en caoutchouc est 30 mm, ce qui est 1 mm plus long que la longueur axiale du manchon d’arbre (2).

6. Structure de protection d’étanchéité pour une extrémité d’étanchéité de poupe d’un moteur de rame selon la revendication 1, caractérisée en ce que le déflecteur intérieur (8) est constitué d’acier et présente un diamètre extérieur de 62 mm.

7. Structure de protection d’étanchéité pour une extrémité d’étanchéité de poupe d’un moteur de rame selon la revendication 1, caractérisée en ce que le premier espacement radial est de 0,10 à 0,15 mm ; et une somme de l’épaisseur du deuxième joint d’eau en caoutchouc et du déflecteur intérieur (8) est 7,75 mm.

8. Structure de protection d’étanchéité pour une extrémité d’étanchéité de poupe d’un moteur de rame selon la revendication 1, caractérisée en ce que le déflecteur extérieur (7) présente un diamètre extérieur de 44 mm, un diamètre intérieur de 29,9 mm et une épaisseur de 8 mn ; et le troisième espacement axial est de 1 à 2 mm.

9. Structure de protection d’étanchéité pour une extrémité d’étanchéité de poupe d’un moteur de rame selon la revendication 1, caractérisée en ce que le troisième espacement axial est 43 mm.