JPS6233439B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Conventional liquid-cooled internal combustion engines have a coolant system that includes a pump that circulates coolant through the engine. A common type of coolant pump has an impeller in the coolant and a belt drive outside the coolant. Additionally, the pump includes a shaft seal between the stationary body and the rotating pump shaft to prevent leakage of coolant from the coolant system.

The requirements for such pumps installed on heavy truck engines are at least 483,000 km.
(300,000 miles) without breaking down. Specific examples of conventional technology for this type of shaft sealing device include British Patent No. 1307082 and British Patent No. 1364144.
No. 1, British Patent No. 1,473,051, and US Pat. No. 3,515,393 disclose the structure of a shaft sealing device. One of the problems with shaft seals of this type relates to the alternating stick-slip operation of the rotating sealing surfaces. UK patent no.
Issue 1473051 refers to this problem as "capture." The two sealing surfaces tend to stick together or become trapped. Once both sealing surfaces are captured and stuck, the bellows member tends to tear. Other issues relate to the materials used and the stresses encountered during use. Coolant fluids are hot and contain chemicals that cause premature aging of the material. These problems are overcome by the present invention through improvements in the selection of materials and the shape and dimensions of each component. The structural features of the invention are described in claim 1. The invention is not a single component improvement, but rather a combination of many related components that work together to create an improved shaft seal.

It is a general object of the present invention to provide an improved shaft sealing device which eliminates most of the above-mentioned drawbacks of the prior art. The shaft seal components are interconnected to prevent their separation due to rotational torque. The materials of these sealing surface components have a relatively long life in the sealing environment, and the flexible bellows is given a reinforced shape to resist torque.
The shaft sealing surface component is made of a material that reduces the magnitude of torque.

Other objects and advantages of the invention will become apparent from the following detailed description of embodiments of the invention as illustrated in the accompanying drawings.

The water pump shown in FIG. 1 has a cast or stationary body 10 and a plurality of holes (not shown) extending through the body and used to secure the body 10 to the block of an internal combustion engine. ing.

Additionally, the fuselage 10 includes a relatively large axially extending opening 11 for receiving a water pump shaft 12.
It is equipped with Shaft 12 is rotatably supported by two axially spaced ball bearings 13, 14 and is mounted in opening 11. A spacer 16 is provided between the outer races of the two bearings 13 and 14. Oil passage 17
are formed through the spacer 16 and a lubricating oil receiving passage 18 is formed in the fuselage 10 so that the bearings 13 and 14 are connected to the passages 17 and 1.
8 can receive lubricating oil. The right side of the bearing 14 is the shoulder step 1 formed on the fuselage 10.
9, a bearing retaining ring 21 is installed in a groove formed in the inner peripheral edge of the opening 11,
It comes into contact with the left end of the bearing 13. In this way, the two bearings 13 and 14 are fixed in place in the opening 11 of the fuselage 10. Shaft 12 is attached to the inner race of bearing 14 by a shoulder 22 formed on shaft 12 and a snap ring 23 mounted in a groove formed on shaft 12.

The shoulder 22 abuts the right side of the inner race of the bearing 14 and the snap ring 23 abuts the left side of the inner race, thereby preventing shaft 12 from moving axially relative to the bearing 14. There is. A lip oil seal 26 is housed in an annular recess 15 extending from the shoulder 19 toward the right of the shoulder 22 of the shaft 12 to prevent lubricating oil from leaking to the right from the bearing surface. There is.

A reduced diameter portion 27 is formed at the left end of the shaft 12, and a water pump pulley 28 is secured to the reduced diameter portion 27 by a press fit interference fit. The outer peripheral edge of pulley 28 has two annular grooves 29 formed therein to receive a V-belt (not shown) that drives pulley 28 and shaft 12 when the engine is rotating. Shaft 12
Alternatively, some engines may be gear driven. The right end of the shaft 12 is provided with a small diameter portion 31 having a pump impeller 32 fixed thereto by a press interference fit. Impeller 32 includes a plurality of radially extending angularly spaced vanes 33 that direct coolant fluid through the engine's coolant system as shaft 12 and impeller 32 rotate. I'll suck it up. The pump body 10 has a coolant inlet passageway 34 formed therein, which communicates to receive coolant entering the pump.
Coolant flows from the passages 34 and is drawn radially outwardly from the passages between the vanes 33 by the rotation of the impeller 32. The left end of the opening 11 has another lip seal 36, which is fitted with a wear sleeve 3 which is secured to the inner periphery of the opening 11 and to the outer periphery of the pulley hub adjacent to the lip seal 36.
Located between 7. A rotating shaft seal 41 (FIGS. 1 and 2) is provided between the pump body 10 and the shaft 12 so that the coolant flowing between the vanes 33 from the passage 34 does not enter the area of the bearings 13, 14. The rotary shaft seal 41 has a generally cylindrical cartridge member 42 which serves as a securing member and has an axially extending outer portion 43 which is secured to the pump body 10 by a press fit into the opening 44 . A sealant is preferably applied to opening 44 to seal this connection. A radially outwardly extending flange portion 45 formed at the right end of the outer circumferential portion 43 serves as a stopper when the rotary shaft sealing device cartridge 42 is press-fitted and sealed into the fuselage body 10. Cartridge member 42 has a radially extending portion 46 on the left side that engages a radial portion 47 of inner ferrule member 48 . The ferrule member 48 includes an axially extending tubular central portion 49 sized to extend around the periphery of the shaft 12 without engaging it. The rotary shaft sealing device 41 further includes an annular cup member 51 having a U-shaped cross section. One U-shaped arm has a tubular portion 52 sized to be fixed to the shaft 12 by press fit or the like.
It consists of As shown in FIG. 2, an annular rotary sealing ring member 53 is disposed between both U-shaped arms. The cross section of this rotary sealing ring 53 is rectangular. An annular rubber boot 54 is mounted between rotary sealing ring 53 and cup member 51, and elastic boot 54 is secured to cup member 51 by any suitable method such as by nitrile-phenol adhesive 56. The rotary sealing ring 53 is fixed to the boot 54 with an adhesive 55. Another method is to replace the boot 54 with a vulcanized rubber coating on the inner surface of the cup member 51. In this case, the rotary sealing ring 53 is fixed to the vulcanized rubber with an adhesive. Examples of suitable adhesives include Product No. 2126 or Product No. 826 sold by 3M Company. The edge 57 of the boot 54 is held under pressure between the outer peripheral edge of the boot 53 and the outer tip arm of the cup 51. An example of an epoxy adhesive that is both an adhesive and a sealant is Product 217 sold by Hughson Chemical Company. A liquid-resistant sealant is applied between the rotary sealing ring 53 and the cup member 51, and this portion is firmly attached. Since the cup member 51 is fixed to the shaft 12, the rotating sealing ring 53 naturally rotates with the shaft 12 during operation of the engine and pump. Furthermore, a rotating shaft sealing device 41
has a stationary sealing ring member 61 having a sealing surface 62 that contacts the rotating sealing ring 53. Rotating seal ring 53 rotates with shaft 12 while stationary seal ring 61 does not rotate, and a fluid film is formed between stationary seal ring 61 and contact surface 63 of rotating seal ring 53. The configuration and dimensions of the stationary sealing ring 61 and the rotating sealing ring 53 are as follows:
This will be explained in more detail below.

The stationary sealing ring 61 serves to support the stationary sealing ring 61 and to connect the stationary sealing ring 61 and the cartridge 42.
A bellows member 66 (Fig. 2-
5), it is supported by the cartridge 42. Cup member 51, rotating sealing ring 53, stationary sealing ring 61
The outer periphery of the bellows 66 as well as the outer surface of a portion of the bellows 66 contact the coolant in the coolant system. Further, the cartridge 42 is connected to the pump body 10 in a sealed state. The bellows 66 is made of a flexible material and has a fixed end 67 fixed to the stationary cartridge 42 and a movable end 68 fixed to the stationary sealing ring 61.
These connections are fixed to accommodate high rotational torques. The static sealing ring 61 is fixed to the bellows by a press fit and a nitrile phenol based adhesive 65 with the properties described above. In the illustrated example, the fixed end 67 is the movable end 68.
Although the bellows 66 is generally cylindrical as shown in FIGS. 2 and 5, these portions may be sized to have a fixed end having a smaller diameter than the movable end. can. Furthermore, the fixed end 67 has an enlarged or bulbous portion 71 which has a greater radial thickness than the central portion 76 of the bellows. The movable end 68 includes a radially inwardly extending flange portion 72 and a cylindrical portion 73. A pair of annular ribs 74 extending radially outward are formed at the junction of these two parts 72 and 73.

A central portion 76 of the bellows 66 is connected to a fixed end 67 and a movable end 68, and the central portion is sloped as best shown in FIGS. Especially with reference to Figure 5,
The central portion 76 has ribs 77 and 78 formed thereon that extend along a plurality of tangent lines. rib 77
slopes clockwise from the small diameter movable end 68 to the large diameter fixed end 67, while the other ribs 78 slope counterclockwise. These plurality of ribs are preferably provided in pairs around the circumference of the central portion 76 at regular angular intervals, and in this description, four ribs 77 and four ribs 78 are provided. There is. As shown in FIG. 5, each pair of ribs 77,
78 merges or joins at the radially inner end adjacent portion 73 of movable end 68 . Additionally, the ribs generally extend tangentially outward from the surface of portion 73. Ribs 77, 78 are preferably provided on the outer surface of the bellows as shown, but could alternatively be provided on the inner surface of the bellows. Figure 2 again
With reference to the fixed end 67 of the bellows 66
The enlarged spherical portion 71 is then sealingly secured between the inner surface of the cartridge 42 and the outer surface of the shaft portion 81 of the ferrule 48. The spherical portion 71 is formed between portions 43 and 46 of the cartridge 42 and is press-fitted into the corner, and the radial flange 82 of the ferrule 48 tightens the spherical body 71 at the corner so that the bellows 66 moves to the right with respect to the cartridge 42. I try not to move. The stationary sealing ring 61 forms a recess in the inner peripheral edge of the portion indicated by 83. bellows 66
The ribs 77, 78 (FIG. 5) angle outwardly from the stationary sealing ring 61 toward the cartridge 42. A spring retainer 86 fits over the inner surface of the flange 72 and the axial portion 73 of the movable end 68, tightly securing the movable end 68 to the stationary sealing ring 61. An annular rib 74 (FIG. 3) is provided to provide a sealed connection between the bellows 66 and the stationary sealing ring 61. Cylindrical compression spring 8
7 extends radially inwardly from the flange of the spring retainer 86 and the radial portion 4 of the ferrule 48;
7, the compression spring urges the spring retainer 86, the movable end 68 of the bellows and the stationary sealing ring 61 in a rightward direction with respect to the rest of the rotary shaft seal. Apart from the radial flange 88, the spring retainer 86 also has an axially extending cylindrical portion 89 and a radially outwardly extending flange portion 9.
1 is placed on the left side. The axial portion 73 of the bellows fits into the outer surface of the cylindrical portion 89 of the spring retainer 86, and the outer edge of the flange 91
is slightly spaced from the inner surface of the cylindrical portion 81.
The rotating shaft sealing device 41 is preferably configured and assembled as follows. Cup member 51 is assembled with rotating seal ring 53 and boot 54 in the manner previously described. The movable end 68 of the bellows is pressed into the recess of the stationary sealing ring 61 and the spring retainer 86 is pressed against the inner surface of the movable end. These portions are formed to provide a tight fit therebetween. Furthermore, adhesive 65 is applied to the bellows flange 72 and the stationary sealing ring 6.
1 to securely seal these two parts and to prevent static sealing ring 61 from separating from bellows 66 due to high rotational torque. Next, the compression spring 87 is attached to the spring retainer 86.
the ferrule 48 to the spring 87.
and coaxially arranged within the bellows 66. The enlarged bulbous portion 71 of the bellows is disposed on the outer surface of the axial portion 82 of the ferrule 48 and then the cartridge 4
2 onto the outer surface of the spherical part 71. Preferably, a lubricant is applied to the outer surface of bulb 71 to facilitate sliding of bulb 71 into cartridge 42. Cup member 51 is secured to water pump shaft 12 and cartridge member 4
2 is fixed to the opening of the pump body 10 as shown in the figure. Apply the sealant to the cartridge 42 and opening 44.
It is preferable to insert it between these parts in order to seal the connection part between them. From the foregoing it becomes clear that the outer surface of the bellows 66 contacts the engine coolant, while the inner surface of the bellows contacts the air within the opening 11. Lip seal 26 prevents lubricant from reaching the inside surface of the bellows.

As previously mentioned, prior art rotary shaft seals were prone to failure and were not reliable for 300,000 miles of service. Failure occurs primarily from rotational torque, and seals are affected by rotational torque and chemicals in the coolant fluid during operation. Rotational torque is generated from the alternating "sticking and sliding" characteristics of the rotary shaft sealing device. The contact surfaces 63 of the rotating sealing ring 53 and the stationary sealing ring 61 are typically separated by a fluid film that occurs between the contact surfaces. If there is a film, there is a small coefficient of wear between the surfaces 63, but this coefficient of friction increases if the coating disappears momentarily, either partially or completely. The action of such a rotating shaft sealing device typically changes while the film is in operation, and the sealing surface 63 changes as the rotating sealing ring 53 rotates relative to the stationary sealing ring 61.
They often become stuck to each other momentarily and then slip. Of course, the rotational torque of the rotating shaft seal increases greatly during the stuck state, and during this period, the stationary sealing ring 61 attempts to rotate together with the rotating sealing ring 53, and tension in the rotational direction is applied to the bellows 66 fixed thereto. When the tension is applied and the tension is relaxed as the rotational torque is reduced and the tension is relaxed, the rotational torque returns to the opposite direction and reciprocates in the rotational direction. The fluctuating rotational torques and oscillatory angular displacements described above cause the prior art rotary shaft seals to fail for a number of different reasons. First, the rotary sealing ring is pulled loose from the cup member. This type of failure can be avoided in the configuration of the illustrated embodiment of the invention by attaching the boot 54 to the cup 51 via an adhesive 55, or alternatively by attaching a rotating sealing ring 53 to the cup 51. This is prevented by adhesive bonding to a layer of sulfurized rubber. Second, the stationary sealing ring is pulled loose from the bellows. This is prevented in the arrangement of the invention by the adhesive 55 and by the tight fit between the static sealing ring 61 and the bellows 6. Thirdly, there is tearing of the bellows. This type of failure is prevented in the illustrated embodiment by ribs 77, 78 which stiffen and strengthen the bellows. The combination of ribs 77, 78, which are tensioned by a rotational torque, provides these advantages, but the ribs can also be used with pumps in which the bellows can be used in either direction of rotation. Preferably, it is provided in both directions as shown. Angular movement failures between the stationary sealing ring and the movable end of the bellows were also common. The bellows remains stationary at the fixed end 67 and does not rotate. The movable end 68 at the other end of the bellows is coupled to the stationary sealing ring 61 and the sealing ring 5
3 and 61 are in a stuck state, they try to rotate together with the sealing ring 61. Therefore, one of the parts between the two ends of the bellows is stationary, and the other part is bent and twisted due to rotation. Regardless of the shape of the bellows, if it is not made of a rigid metal, this bending will generate heat of deformation within the bellows. When this heat is added to the heat of the coolant liquid, the life of the bellows tends to be shortened. Heat ages the bellows material, making it more susceptible to tearing. If only bending is done, this will be repeated many times before it will break due to fatigue failure. If this member is hot, the combination of flexing and heat will accelerate the failure and failure will occur prematurely. The tendency for failure due to bending is thereby reduced in embodiments having ribs 77, 78 which stiffen the bellows, and thus the amount of bending is also reduced. Additionally, the central portion of prior art bellows generally extends radially. The pressure of the coolant liquid is close to plus approximately 1 kg/cm (14 psi) in the pressurized device. In the prior art shaft seal of U.S. Pat. No. 2,884,268, the bellows has a radially central portion. When the fluid pressure outside the bellows increases, the central portion of the bellows tends to bulge out from the high pressure side and is pressed against other members of the shaft sealing device. If the bellows undergoes a rotational angular displacement as described above, the bellows will be rubbed by other parts of the shaft sealing device and a hole may be formed. When the bellows has a sloped center portion as in the present invention, the tendency to rub and wear appears to be reduced.

Furthermore, when excessive pressure is applied to the bellows of the prior art, the central portion is bent into a folded shape, and foreign matter accumulates there. As the member undergoes rotational angular displacement, foreign particles cause wear and create holes. Failure due to damage due to bending of the bellows is prevented by forming the central portion of the bellows into an inclined shape. In the embodiment with ribs 77, 78, the ribs 77,
The 78 section is stiffer to reduce bending and inward expansion due to the rib and bevel design. The reinforcement of the central section by the ribs reduces vibration and bending, thereby reducing heat generation and the amount of wear. Damage due to rotational torque is also reduced by the design of the rotating sealing ring 53 and the stationary sealing ring 61. Both of these parts are made of silicon carbide, a very hard material. Two very hard materials are used, although it is customary in rotating shaft sealing technology to use a hard material for one seal portion and a less hard material for the other seal portion. This combination is advantageous in minimizing the dynamic torque of the stationary sealing ring 61 by providing a thin, relatively small radial width sealing surface, which will be described later.
When the rotating sealing ring 53 rotates relative to the stationary sealing ring 63, the friction therebetween generates a steady torque. Variable torque is generated by periodic attachment and capture. Dynamic torque is their sum. The use of two hard materials is advantageous because it reduces the abrasion of the sealing surfaces in the event that abrasive debris enters between the sealing surfaces of the stationary sealing ring 61 and the rotating sealing ring 53. Also, interfacial sealing films are more easily formed with narrow radial width sealing surfaces. The aforementioned narrow sealing surface refers to the size of the contact engagement surface 63 (FIGS. 2, 6). As shown in FIG. 6, the sealing ring portions 53, 61 are annular, and the engagement surface of the sealing surface 63 is shown by hatching. The radial width of the sealing surface is approximately 1.143mm.
(0.045 inch) to approximately 1.778 mm (0.070 inch), it has been found that very advantageous results are obtained with less wear and good liquid film formation, and this is also important to the present invention. That's the part. The sealing surface is approximately 1.651 mm (0.065 inch) as it operates at low dynamic torque during normal operation.
dimensions are also desirable for ease of fabrication. If the width of the sealing contact surface is less than 1.143 mm, the contact area will be too small and excessive wear will occur. Also, 1.651mm
If it is larger, it becomes difficult to form a good liquid film between the surfaces. Reducing the dimensions to 1.143 mm (0.045 inch) significantly reduces the dynamic torque at critical lubrication conditions. The critical lubrication state is an excessive state in which the liquid film between the seal surfaces 63 changes from a state where both sides are wet to a state where the liquid film disappears and both sides become dry and the sealing ring is stuck, or vice versa. It means progress. Considering all of the above factors, the optimal width is approximately 1.651 mm (0.065 inch). The above-mentioned dimensions are optimal when silicon carbide is used for both the sealing rings 53 and 61, and when silicon carbide is used for one member and carbon is used for the other member. It is also suitable for operation under the surface loads that normally occur in technical shaft seals. A seal with a silicon carbide seal face and a radial dimension of 1.651 mm (0.065 inch) reduces dynamic torque under various operating conditions, producing a new and unexpected result of reduced coefficient of friction. . Additionally, this hard material can withstand abrasion of the sealing surface despite its relatively small radial width. These results are attributable to a continuous and stable fluid film that is easily maintained due to the improved 0.065 inch width dimension. The radial width of the conventional sealing face is approximately twice that of the structure of the present invention.
Although the diameter of the sealing surface is not believed to be critical, the outer diameter of the particular example may range from approximately 30861 mm (1.215 inches) to approximately
It was between 31115 mm (1.225 inches). Figure 2-5
In the construction according to the invention shown in Figure 1, the material of the bellows is a fluorinated elastomer, which is a peroxide-cured copolymer of tetrafluoroethylene and propylene, which are alternated in the monomer process. This material has been shown to withstand amine suppressed coolant chemicals at elevated engine temperatures (approximately 200 degrees Fahrenheit) and also resists oxidative degradation. Adhesive 55, with the exception of epoxy, is made of a nitrile phenol based material that is resistant to coolants. The metal part of the seal resists corrosion and
It is preferable to make it from stainless steel, which reduces the effects of galvanic corrosion. The bellows may be constructed with the aforementioned ribs and may also be made of a peroxide-cured nitrile compound to extend the life of the seal. Figure 7
illustrates a bellows 101 that has the same shape as bellows 66 but is a composite of two materials. In this description, the bellows consists of two layers 102,1
03. The outer layer 103 is made of a peroxide cured nitrile compound and the inner layer 102 is made of a fluoroelastomer. The former resists coolants, the latter resists oxidation.
Instead of two relatively thick layers as shown in the figure,
The bellows is basically made of peroxide-cured nitrile and can have a fluoroelastomer applied to its inner surface.

From the foregoing description, it is apparent that a new and useful rotary seal arrangement has been created. The sloping of the central portion 76 of the bellows 66 is important in the present invention because this shape prevents the bellows from coming into contact with other members of the shaft seal if the aforementioned bulge were to occur. . The provision of ribs 86, 87 in the center of the bellows in accordance with embodiments of the present invention serves to make the bellows stiffer and stronger. Sticking of the sealing surface in the center of the bellows - a sealing ring 53 which is bent in the circumferential direction when a sliding action occurs and which is permanent due to the process.
and 61 slight wear. The directional deflection therefore only needs to make it possible to maintain sealing contact even with wear of the sealing ring. The materials used for the bellows and other shaft seal components are resistant to deterioration, and the hard materials used for the two sealing surfaces improve performance, and the joints of the shaft seal can be constructed in an improved manner. Bonded in position with adhesive to withstand high rotational torque.

[Brief explanation of the drawing]

The drawings show an embodiment of the invention, FIG. 1 is a longitudinal sectional view of a coolant pump equipped with a face seal, FIG. 2 is an enlarged longitudinal sectional view of the face seal, and FIG. 3 is an enlarged sectional view of the bellows of the seal. Figure 4 is a cross-sectional view taken along the line 4--4 in Figure 5, Figure 5 is a cross-sectional view taken along the line 5-5 in Figure 3, and Figure 6 is a cross-sectional view taken along the line 6-6 in Figure 2. Figure 7 is the fourth
Another embodiment is shown in a sectional view similar to the drawing in the figure. DESCRIPTION OF SYMBOLS 10... Body, 12... Shaft, 13, 14... Bearing, 28... Pulley, 32... Pump impeller, 41... Face seal, 42... Cartridge, 53
...Sheet washers, 61...Seal rings, 6
6...Bellows.

Claims (1)

[Scope of Claims] 1. A rotating shaft sealing device for sealingly connecting a rotating shaft 12 and a stationary body 10 surrounding the shaft, comprising first and second sealing ring members 53, 51, Members 51, 54 secure the first sealing ring 53 to the shaft 12, a second sealing ring 61 is secured to the stationary body 10, and both sealing rings are subjected to rotational torque during engine operation. , a bellows 66 connects the second sealing ring 61 to the stationary body 10, and both sealing rings have a contact sealing surface 63, wherein both sealing rings 53, 61 are made of a relatively hard material with a low coefficient of friction. at least one sealing ring is made of silicon carbide, the radial width of said sealing surface 63 is relatively small so as to form a continuous stable fluid film and reduce dynamic torque, and the adhesive 65 fixes the bellows 66 to the second sealing ring 61, the adhesive 65 is made of a nitrile phenol based material, and the bellows 66 is axially and The sealing device includes a radially outwardly sloped central portion 76, which portion 76 is flexible in both the axial and circumferential directions. 2. The sealing device according to claim 1, characterized in that both sealing members are made of silicon carbide. 3. In the sealing device according to claim 1, the radial width of the surface 63 is approximately 1.143 mm.
(0.045 inch) to approximately 1.778 mm (0.070 inch). 4. The sealing device according to claim 3, wherein the radial width is approximately 1.651 mm (0.065 inch). 5. In the sealing device according to claim 3, the boot 54 is bonded to the cup member 51 by means of a nitrile phenol based adhesive 56.
and is fixed to the first sealing ring member 53 by an epoxy adhesive 55. 6. The sealing device according to claim 6, wherein the boot 54 is made of a rubber coating vulcanized on the cup member 51, and the first sealing ring member 53 is fixed to the rubber coating with an epoxy compound. shall be. 7. In the sealing device according to claim 1, the bellows 66 has a fixed end 67 fixed to the cartridge member 42, a movable end 68 fixed to the second sealing ring member 61, and a movable end that connects the fixed end and the movable end. The ends and the central portion 76 are generally annular, and the bellows 66 includes a plurality of bellows formed in the central portion 76 and extending generally tangentially between the fixed and movable ends. Rib 77,7
8. 8. The sealing device according to claim 7 is characterized in that the ribs 77, 78 are formed on the outer surface of the central portion 76. 9. In the sealing device according to claim 7, the plurality of ribs 77, 78 include a first set of ribs 77 extending along a tangent in one direction and a first set of ribs 77 extending along a tangent in another direction. It is characterized by including a second set of ribs 78. 10. The sealing device according to claim 1 is characterized in that the material of the bellows 66 is a fluorinated elastomer. 11. The sealing device according to claim 1, characterized in that the material of the bellows 66 is a peroxidation-cured copolymer of tetrafluoroethylene and propylene, which are alternated in the monomer process. 12 In the sealing device according to claim 1, the bellows 66 has an inner layer 102 and an outer layer 10.
3, the outer layer is made of a peroxide-cured nitrile compound, and the inner layer is made of a fluoroelastomer. 13. In the sealing device of claim 1, in use, one side 102 of the bellows 66 is in contact with a coolant and the other side is in contact with air, said both sides being resistant to said coolant and oxidation, respectively. It is characterized by 14. In the sealing device according to claim 13, the bellows 66 includes a first layer 102 on the one surface and a second layer 103 on the other surface. 15. The device according to claim 1, characterized in that the bellows 66 are made of a peroxide-cured nitrile compound.