JPH04140577A - Sealing device and manufacture thereof - Google Patents

Abstract

PURPOSE:To shorten machining time and a manufacturing process by forming a delicate Al2O3 membrane at the sliding face of one seal ring, and jointing a porous ceramic sliding member to the sliding face side of the other seal ring. CONSTITUTION:The sliding face of an Al alloy made seal ring 21 is ground to make wavy deformation small, and then a delicate Al2O3 membrane is formed at the machined face. This Al2O3 membrane 24 is formed by electrochemical growth so as to have constant membrane thickness. Also, Si3N4 combined SiC is suitable for porous ceramics used for the sliding member 22 of the seal ring 21 of joint structure. Since this ceramics hardly has measure change at the time of sintering, the deformation of the sliding member 22 is small. Accordingly, the waviness of the sliding face of the seal ring 21 of joint structure with this ceramics jointed to the sliding part is also small. This results in shortening machining time for reducing the waviness of the sliding face and thereby a manufacturing process.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a sealing device using a seal ring, and in particular, a seal ring made of a He1 alloy with an anodized film and a sliding member are bonded together using an adhesive. The present invention relates to a seal device in which a seal ring having a joint structure is joined using a seal ring.

[Conventional technology]

As a prior art sealing device, a sealing device used in a traveling reduction gear of a hydraulic excavator, etc., described in Jitsugan Sho 62-49059 will be exemplified and explained.

Fig. 2 shows a sectional view of a reducer to which a sealing device is applied, and in Fig. 2, l is a cylindrical fixed side casing fixed to a machine frame such as a hydraulic excavator via a screw hole IA,
A hydraulic motor 2 as a traveling motor is fixed to one end of the casing 1 via a bolt 3.
is provided with an output shaft 2A that derives rotational output.

4 is a reducer that reduces the rotational output from the output shaft 2A;
The speed reducer 4 includes a rotating side casing 6 rotatably supported on the other end side of the stationary side casing 1 via a bearing 5, and a one-stage or multiple-stage planetary gear reduction built in the rotating side casing 6. The rotation side casing 6 is rotated at a predetermined deceleration speed.

Reference numeral 7 denotes a sprocket fixed to the flange portion 6A of the rotating side casing 6 via bolts 8. The sprocket 7 meshes with a track link of a crawler (not shown) and drives the crawler to move the hydraulic excavator above the ground. It is designed to run with

Further, numeral 9 denotes a sealing device installed on the inner peripheral side of the opposing ends IB and 6B of each of the casings 1 and 6, and this sealing device 9 prevents the oil inside each casing 1.6 from leaking to the outside. This also prevents dirt, mud, rainwater, etc. from entering into each casing 1.6. Here, the sealing device 9 is located at the end IB, as shown in FIG.

A pair of seal rings 2 installed on the inner surface of 6B, each seal ring 21 and the ends 1alB, 6B.
A pair of O-rings 11 are sandwiched between the seal rings 21, and each seal ring 21 has an annular groove 2 formed near the outer circumferential side and having a U-shaped cross section on the axially opposing surfaces of each seal ring 21.
1A is provided. A sliding member 22, which will be described later, is bonded to the acceptance groove 21A with an elastic adhesive 23 to form a sliding surface.

Further, the outer circumferential surface 21B of each seal ring 21 is formed in a concavely curved shape and inclined outward in the axial direction.
When held, the elastic force of each 01J ring 11 applies a pressing force to each sliding surface to provide sealing properties. The magnitude of this pressing force can be adjusted by widening or narrowing the gap 13. The seal ring 21 (see FIG. 4) is made of a corrosion-resistant light alloy material such as an aluminum alloy or a zinc alloy. Further, 22 is an elastic adhesive 23 in each annular groove 21A.
Each sliding member 22 is made of SiC, Al1[]3, lrD, , S
It is made of a dense ceramic material having corrosion resistance and abrasion resistance, such as No.

Here, the elastic adhesive 23 is made of, for example, a silicon-based adhesive, and is formed to be elastically deformable even after the sliding member 22 is bonded. Since the dense ceramics of the sliding member used here has a large dimensional change rate of 15 to 20% during sintering, the sintered body is highly deformed. Therefore, the sliding surface of a seal ring to which this is bonded has large undulations and cannot be used as a seal ring, so machining is required.

However, since the ceramic of the sliding member is a rigid body and is bonded with an elastic adhesive, machining is difficult, and machining to reduce waviness on the sliding surface requires a long time. However, there is a drawback that the cost of the sealing device is high.

In addition, (1) manufacturing the seal ring base, (2) manufacturing the ceramic sliding member, (3) mechanical grinding to reduce deformation of the ceramic sliding member, (4) joining the ceramic sliding member, and (5) The manufacturing process begins with step (5) of mechanically polishing the sliding surfaces of the joined seal rings, which is a long process and has the drawback of increasing the cost of the sealing device.

[Problem to be solved by the invention]

The above conventional technology takes into consideration the fact that when a sliding member made of dense ceramics that is highly deformed is joined, the undulation deformation of the sliding surface of the seal ring becomes large and that the manufacturing process of a seal ring with an adhesive structure becomes long. However, there was a problem in that the cost of the sealing device was high.

SUMMARY OF THE INVENTION An object of the present invention is to provide a sealing device that can reduce waviness on a sliding surface, reduce machining time and manufacturing steps, and reduce cost.

[Means to solve the problem]

In order to achieve the above object, in the present invention, the sliding surface of at least one seal ring is anodized to form a dense A
l2O. It is made of ^1 alloy with an integral structure that forms a membrane, and a preferred structure is a bonded structure in which the other seal ring is attached to the sliding surface side and a porous ceramic sliding member is bonded via an elastic adhesive. This is a sealing device with the following configuration.

The monolithic seal ring is manufactured by mechanically grinding a surface corresponding to the sliding surface of an Al alloy seal ring to reduce waviness deformation, and then forming a dense Al2O3 film on the machined surface. Since this ^1,03 film is formed by gradual electrochemical growth, the film thickness is constant. Therefore, the waviness of the membrane surface serving as the sliding surface is very small. Therefore, the time required for mechanical polishing to reduce waviness on the sliding surface can be shortened. In addition, since no elastic adhesive is used, it has high rigidity and is easy to mechanically polish. The manufacturing process consists of (1) producing a material for machining the ^1 alloy seal ring, (2) machining the surface corresponding to the sliding surface of the seal ring, (3) forming an Al2O3 film by anodizing, (4) Becomes a sliding surface＾１□
The manufacturing process is one less than the conventional bonded structure, with four steps including mechanical polishing of the 03 membrane surface.

In addition, suitable porous ceramics to be applied to the sliding member of the seal ring of the joint structure are, for example, 513N4 bonded SiC obtained by heating a green compact of SiC powder at a final temperature of 1350° C. in an N2 atmosphere.

Since this ceramic undergoes almost no dimensional change during sintering, the deformation of the sliding member is extremely small.

Therefore, the waviness of the sliding surface of the seal ring of the joined structure in which this is joined to the sliding portion is also small. Therefore, the time required for mechanical polishing of the sliding surface in order to reduce waviness can be extremely short.

In addition, since this is a material with excellent mechanical polishability,
Even if there are undulations, the polishing time may be short.

As above. The sliding surface of the Al alloy seal ring is anodized to form an Al2O3 film, and the sliding surface of the Al alloy seal ring is preferably made of porous ceramic. By applying a seal ring with a joint structure that uses manufactured sliding members joined together, the time for mechanical polishing of the sliding surface and the manufacturing process can be shortened compared to conventional seal rings, and the cost of the seal device can be reduced. .

In order to achieve the above object, the thickness of the sliding surface is set to 5 to 150 IJm, and the hardness is set to HV300 to 500.
It is desirable that the relative density be 80% or more.

If the film thickness is less than 5 μm, the lifespan will be short;
If this is the case, it takes a long time to form the film and the film thickness becomes non-uniform, so that the mechanical polishing time required to reduce the waviness of the film surface becomes long, making it impossible to manufacture an inexpensive seal ring.

Furthermore, if the hardness of the film is less than HV300, the wear resistance will be poor and the lifespan will be shortened, and if the hardness is HV5f)0 or more, the wear of the mating device will be large and the lifespan of the seal ring will be shortened. If the relative density is less than 80%, the strength of the membrane is weak, the wear resistance is poor, the life of the seal ring is shortened, and an inexpensive seal ring cannot be manufactured.

Moreover, in order to achieve the above object, it is desirable that the relative density of the porous ceramic is 60 to 90%.

If the relative density is less than 60%, the pore size becomes large and the concave edges of the sliding surface are likely to break, and these broken particles are incorporated into the sliding surface, thereby promoting wear and reducing the life of the seal ring. Keep it short. If the relative density is 90% or more, the passage connecting the pores, which is the supply path for lubricant to the sliding surface, becomes narrow, and the lubricant is insufficiently supplied to the sliding surface, resulting in oil film failure. This tends to cause wear, which accelerates wear and shortens the life of the seal ring.

In addition, in order to achieve the above purpose, the pores of porous ceramics consist of small pores and large pores, and the small pores are 1 to 5 μm in size.
It is desirable that the large pores have a power of 10 to 30 μW and that these are connected.

Before assembling the seal ring into the device, impregnating the sliding member of the seal ring with a bonded structure made of porous ceramic sliding members with lubricating oil will prevent oil film from running out on the sliding surface. Therefore, the life of the seal ring can be extended. However, if the size of the small pores that serve as oil passages when impregnating with lubricating oil is less than 1 μm, it is not easy to impregnate the lubricating oil. Further, if the thickness is 5 μm or more, the mechanical strength of the porous ceramic becomes weak, resulting in a decrease in wear resistance and shortening the life of the seal ring.

Furthermore, if the size of the large pores is less than 10 μm, the lubricant cannot be trapped sufficiently even if it is impregnated with the lubricant, resulting in insufficient supply of lubricant to the sliding surfaces, causing oil film depletion and sealing. Shorten the life of the ring. Also, 3
If the diameter is 0 μm or more, the lubricating oil that has once penetrated will flow out from the pores due to small vibrations, etc., and the lubricating oil cannot be supplied to the sliding surface, resulting in a lack of oil film and shortening the life of the seal ring.

Furthermore, in order to achieve the above object, it is desirable that the waviness of the sliding surface of the seal ring be 3 to 30 μm. It takes a long time for finishing to reduce the waviness to less than 3 μm.
It is not possible to manufacture cheap seal rings. Also, the undulation is 3
If the diameter is 0 μm or more, lubricating oil will leak more from the sliding surface, and the performance of the seal ring will deteriorate.

In addition, in order to achieve the above object, instead of the AI□D3 film, a hard film of metal nitride, carbide, boride, etc. may be used. It is also possible to use an Al alloy seal ring base with a hard composite layer near the surface on the sliding surface side.

The hardness of the hard film of carbide, carbide, boride, etc. formed on the sliding surface and the composite layer near the sliding surface is determined by the hardness of the Al2O. If it is not equal to or better than the membrane, the wear resistance will be poor, the life of the seal ring will be short, and it will not be possible to manufacture an inexpensive seal ring.

The above-described sealing device can be applied to a sealing device for a bearing portion of a crawler drive wheel of a construction vehicle or the like having a crawler track, or a rolling wheel. Examples of construction vehicles include bulldozers and hydraulic excavators.

In addition, there are sealing devices suitable for the above purpose. The sliding surface of the Al alloy seal ring is anodized to Al2[+3 I
nI! a step of bonding a porous ceramic sliding member to the sliding surface of the seal ring base via an elastic adhesive, a step of mechanically polishing the sliding surface of the seal ring, and a step of bonding the porous ceramic to the sliding surface of the seal ring base. a step of impregnating lubricating oil into the pores of the ceramic of the sealed seal ring, the seal ring having an integral structure with an Al2O3 film formed on the sliding surface and the sliding member are porous ceramics, and the pores of the ceramic are impregnated with lubricating oil. It can be manufactured by a process of setting an adhesive structure seal ring inside the housing via a circle.

The Al2O3 film can be produced by machining the sliding surface of an Al alloy seal ring to create a smooth surface and then anodizing the sliding surface using a sulfuric acid-based electrolyte or the like. This film surface can be polished using, for example, a disk-shaped lapping machine. Bonding is performed, for example, by sandwiching a rubber-based elastic adhesive between the seal ring base and the porous ceramic sliding member, and applying pressure after heating. Mechanical polishing of the sliding surfaces is performed using, for example, a horizontal axis rotary grinder or a disk-type lapping machine, respectively. Further, impregnation with lubricating oil is carried out, for example, by heating a seal ring having an adhesive structure immersed in lubricating oil.

[Effect]

Each ring of the Sea Jl device, which consists of a pair of conventional seal rings, has a bonded structure in which a dense ceramic sliding member is bonded to the sliding surface side of the AI alloy seal ring base via an elastic adhesive. It is. The sliding member and the thin plate-shaped ring are made of engineering ceramics (Al2O3, 5i3L, SiC,
These include ZrL and Sialon. These ceramics have a large dimensional change rate of 15 to 20% during pre-sintering and are dense, so if a thin plate link-shaped sliding member is manufactured from these materials, the waviness deformation force < 200 to 1, OO0
It is as large as μm. The extent of this deformation) The waviness of the sliding surface of the seal ring to which the sliding member is joined is also large. In order to make this into a seal ring, the required force is to make the surface waviness 3 to 30 μm, so the sliding surface of the seal ring bonded with the above-mentioned dense ceramic sliding member is significantly reduced (this is mechanically ground). (This requires mechanical polishing, which takes a long time, making it impossible to manufacture inexpensive seal rings.)

In contrast, in the present invention, one of the pair of seal IJ rings has a sliding surface waviness of 3 μm.
After mechanically grinding to less than m, this surface is anodized ^
By forming the l,03 film, a seal ring with small waviness can be manufactured.

Since it is easy to machine the surface waviness of the sliding surface of the seal ring to 3 μm or less, the machining time can be shortened. In addition, since the anodizing treatment of the ^1 alloy is an electrochemical treatment method and is a method that is becoming increasingly industrialized, it is possible to easily form a ^l, 03 film with a uniform structure and a constant film thickness. can. For this reason, since the waviness of the Al2O3M surface serving as the sliding surface is small, the waviness of the sliding surface can be reduced to 3 to 30 μm by short-time mechanical polishing.

As above. After machining the sliding surface side of the Al alloy seal ring base, an Al2O3 film is formed on this surface, and the integral structure of the seal ring, in which this surface becomes the sliding surface, has a smoother sliding surface than the conventional adhesive structure seal ring. To reduce the undulation
Mechanical polishing time can be reduced.

On the other hand, the seal ring of the adhesive structure of the present invention, which is a counterpart to the integral structure seal ring described above, has the same adhesive structure as the conventional seal ring, except that the sliding member is made of porous ceramics. This porous ceramic is made of Si powder and SiC, for example.
A 5iJn bonded SiC material manufactured by heating a powder compact at a final temperature of 1,350° C. in an N2 atmosphere can be applied. This material has a dimensional change rate of 0.3% or less during sintering, which is as low as /100 compared to dense ceramics known as conventional engineering ceramics. Therefore, the waviness deformation of the porous ceramic thin plate ring-shaped sliding member after sintering is as small as 5 to 50 μm. The waviness of the sliding surface of the adhesive structure seal ring to which the sliding member with small deformation is bonded is also small. Therefore, the time required for mechanical polishing to reduce waviness on the sliding surface of the seal ring may be shortened.

As mentioned above, Al2O. In a sealing device that uses a pair of integral structure seal ring with a membrane surface as a sliding surface and an adhesive structure seal ring with porous ceramic as a sliding surface, each seal ring is designed to prevent waviness on the sliding surface. The time required for mechanical polishing to reduce the size can be shortened. Also,
One of the pair of seal rings of the present invention is of integral construction.

This requires a shorter manufacturing process than conventional methods. In other words, in the conventional adhesive structure, (I) manufacturing the seal ring base, (
n) Production of 1-dense ceramic sliding member, (I) Grinding to reduce waviness deformation of the ceramic sliding member, (IV) Bonding of the ring base and ceramic sliding member, (V) Sliding after adhesion In contrast to the five steps of mechanical polishing of the moving surface, in the case of an integrated structure, there are (1) manufacturing of the seal ring base;
(II) Precision mechanical grinding of the seal ring sliding surface, (III
) Anodizing the mechanically ground surface, (■) Mechanically grinding the anodized surface, which is one fewer step in the present invention, so the cost of the sealing device can be reduced also in terms of the number of manufacturing steps.

Furthermore, it will be explained that according to the present invention, the life of the seal ring is extended compared to the conventional one, and from this point of view as well, the cost of the sealing device can be reduced.

Approximately half of the circumference of the seal ring incorporated in the seal device is immersed in lubricating oil. One of the pair of seal rings is rotating, and the lubricating oil is transferred from the sliding part on the inner circumferential side of the seal ring to the sliding surface due to the internal pressure and adhesive force generated by the temperature rise in the sealing device. An oil film is formed on the surface, reducing sliding resistance. However, if the seal ring is separated from the lubricating oil surface and exposed, the lubricating oil supply will be insufficient, the oil film will break, the sliding resistance will increase, seizure will occur easily, and the life will be shortened. .

In the present invention, the mechanism for lubricating the sliding surfaces has been improved, and the number of lubricating oil supply sources has been increased compared to the conventional method.

In other words, in a seal ring with a bonded structure in which porous ceramics is used as a sliding member, the pores of the ceramic are impregnated with lubricant oil before it is assembled into a sealing device, and the above-mentioned lubricant supply mechanism to the sliding surface is activated. It was also possible to supply water to the outside through the pores.

Since the sliding member has many pores, lubricating oil is supplied to the sliding surface from multiple points, and the life of the seal ring can be extended without running out of the oil film. especially,
This is very effective during the initial operation of the sealing device.

Furthermore, the present invention will explain how one of the sliding surfaces is made of dense ceramics and the other is made of porous ceramics to extend the seal life. Since seal rings attached to construction machinery and the like are in direct contact with external earth, sand and muddy water, fine particles in the earth, sand and muddy water may infiltrate the sliding surfaces. In this case, if the ceramic material on the sliding surface is dense and dense, the sliding surface will be destroyed by the mixed particles, increasing the sliding resistance and significantly shortening the seal life.

However, in the present invention, on the other hand, since porous ceramics are used, the pores of the ceramics absorb fine particles and do not destroy the sliding surface, so the seal life can be extended, and the sealing device The cost of production can be reduced. Furthermore, as in the present invention, when one of the sliding surfaces is made of porous ceramics and the other is made of dense ceramics, the bonding force of the crystal grains of the porous ceramics is smaller than that of the dense ceramics. Even if the contact between the sliding surfaces is poor, wear of the porous ceramic takes precedence, and it easily blends in with the sliding surface of dense ceramics, making it possible to create a sliding surface with excellent sealing performance in a short period of time.

Therefore, it is not necessary to minimize the waviness of the sliding surface by machining, and the mechanical polishing required to reduce the waviness only takes a short time. In this way, the sealing device can be manufactured at low cost.

〔Example〕

Hereinafter, the present invention will be specifically explained using drawings, but the present invention is not limited thereto.

Embodiment 1 An embodiment of the present invention will be described based on the enlarged sectional view of FIG. 1 showing the main parts of a sealing device. In the embodiment, the same components as those of the prior art shown in FIGS. 2 to 4 described above are given the same reference numerals, and the explanation thereof will be omitted.

In FIG. 1, 21. ．． Reference numeral 21 denotes a seal ring disposed on the inner surface side of the ends IB and 6B of each casing 1.6, one of which is made of an aluminum alloy die-cast material (ACD12), and faces facing each other in the axial direction. A groove 21A having an angular cross-section is provided in the groove 21A. A sliding member 22 is bonded to 21A with an elastic adhesive 23. The sliding member has a relative density of 80% S+sL
It is a porous ceramic made of bonded SiC. The ceramic is 3i3L produced by the reaction of metal Si and N2.
This is a ceramic bonded with C particles, and the distribution of holes is uniform. The waviness of the sliding surface after polishing is 10 μm or less, and the surface roughness Rmax is 5 μm or less. Furthermore, before the seal ring was assembled into a sealing device, the pores of the ceramic were impregnated with lubricating oil. Also, the other seal ring 2
1 is an aluminum alloy die-cast material (ACD12)
The surfaces facing each other in the axial direction have a dense ^1゜0
．． A film 24 is formed, and the Al2O3 film serves as a sliding surface. The waviness of the sliding surface is 10 μm or less, and the Al2O3
The relative density of the membrane is 95%.

Further, the outer circumferential surface 21B of each seal ring 21 is formed in a concave curved shape and inclined outward in the axial direction, and each O-ring 11 is sandwiched between it and the inner circumferential surface IC16C of each casing 1.6. At this time, the elastic force of the O-ring 110 applies a pressing force to each of the sliding surfaces to provide sealing properties, prevent dirt, mud, rainwater, etc. from entering from the outside, and an oil film is always formed on the sliding surfaces. was used, and no burn-in occurred. Also,
Although the pressure inside the sealing device was increased to a maximum of 1.5 atm, no leakage of lubricating oil was observed.

According to this embodiment, there is an effect that an inexpensive sealing device can be manufactured.

〔Effect of the invention〕

According to the present invention, the manufacturing cost of the sealing device can be reduced because a seal ring with an integral structure is used that can shorten the machining time and manufacturing process for reducing waviness on the sliding surface.

Furthermore, since the oil film on the sliding surface does not run out, the life of the sealing device can be extended.

[Brief explanation of the drawing]

FIG. 1 is an enlarged sectional view of the main parts of a sealing device according to an embodiment of the present invention, and FIGS. 2 to 4 show the prior art.
Fig. 2 is a partially cutaway front view showing the reducer to which the sealing device is applied, Fig. 3 is an enlarged sectional view showing the sealing device in 2rA, and Fig. 4 is the seal shown in Fig. 3. FIG. 3 is a cross-sectional view of one of the rings. 1.6...Casing, Ic, 6C...Inner peripheral surface, 1
1...0 ring, 21...Seal ring, 21Δ・
... L-shaped groove, 21B ... outer peripheral surface, 22 ... sliding iJJ
Part shrine, 23... Elastic adhesive, 24... Hard ^l□0
3 membranes. Patent applicant: Kuchitachi Manufacturing Co., Ltd. Hitachi Construction Machinery Co., Ltd.

Claims (8)

[Claims] 1. A pair of seal rings are disposed on the inner surface of the casing that rotates relatively, and the surfaces facing each other in the axial direction serve as sliding surfaces, and each seal ring and each casing are sandwiched between the seal rings and the elastic force. and an O-ring that applies pressing force to the sliding surface of each seal ring, wherein one of the pair of seal rings has a sliding surface that is anodized to form a dense Al_2O_3 film.
1. A sealing device characterized in that it is made of L alloy, and the other side has a structure in which a sliding member made of porous ceramics is bonded to the sliding surface side. 2. The film thickness of the dense Al_2O_3 film is 5 to 150 μm.
The sealing device according to claim 1, wherein the hardness is HV300 to HV500 and the relative density is 80% or more. 3. The porous ceramic sliding member has a relative density of 60
9. The sealing device according to claim 1, wherein the sealing device is 90%. 4. The porous ceramic sliding member contains small pores and large pores, the small pore size is 1 μm to 5 μm, the large pore size is 10 to 30 μm, and the large pores are connected to the small pores. The sealing device according to claim 1, characterized in that: 5. 2. The sealing device according to claim 1, wherein the sliding surface of the seal ring has an undulation of 3 to 30 μm. 6. The sliding surface of one seal ring is made of dense Al_2O_
2. The sealing device according to claim 1, wherein instead of the three films, a hard film made of nitride, carbide, or boride is used, or a hard composite layer is used near the sliding surface. 7. A step of anodizing the sliding surface of the Al alloy seal ring to form a hard Al_2O_3 film, a step of bonding a porous ceramic sliding member to the sliding surface of the seal ring base via an elastic adhesive, A process of grinding and polishing the sliding surface of the seal ring, a process of impregnating lubricating oil into the pores of the ceramic of the seal ring to which the porous ceramics are bonded, and a seal ring with an integrated structure in which an Al_2O_3 film is formed on the sliding surface. and the sliding member is made of porous ceramic, and the method further comprises the step of setting a seal ring having an adhesive structure in which the pores of the ceramic are impregnated with lubricating oil inside the housing via an O-ring.
7. A method of manufacturing a sealing device according to any one of items 6 to 6. 8. A bearing for a crawler drive wheel or a rolling wheel of a vehicle having a crawler track using the sealing device according to any one of claims 1 to 6.