JPH0476085A - Differential limiting device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to an improvement in a differential limiting device installed in a vehicle.

[Prior Art] A differential limiting device has a first friction plate and a second friction plate that are integrally engaged in a rotational direction with two relatively rotatable parts of a differential device, and a first friction plate and a second friction plate. It has a structure in which plates and second friction plates are alternately stacked on top of each other, and the differential movement of the differential gear is limited by a so-called multi-plate clutch mechanism.

Initially, cold-rolled steel plates were used for both the first friction plate and the second friction plate constituting the multi-plate clutch mechanism of a conventional differential control device. In a configuration in which both of these cold-rolled steel plates are used, the static friction coefficient is higher than the kinetic friction coefficient, the absolute value of the friction coefficient is higher, and the fluctuation range of the friction coefficient (
Due to the large variation, stake slips occur,
There was a problem with abnormal noises.

As a solution to this problem, Utility Model Application No. 5713003
No. 9 discloses a method for forming a self-lubricating surface film containing particles of molybdenum disulfide or Graphi 1 on the sliding surfaces of friction plates constituting a multi-disc clutch mechanism. Furthermore, the Utility Model Application Publication No. 2003 according to the invention of the present inventors
Japanese Patent No. 30530 discloses a method of forming the sliding surface of a friction plate from a carbon fiber-reinforced carbonaceous composite.

[Problems to be Solved by the Invention] In the differential limiting device that uses the friction plates described above with a self-lubricating surface film formed thereon, the coefficient of friction between the friction plates becomes small, resulting in the occurrence of stake-slip and abnormal noise. Decrease. However, because the coefficient of friction is small, there is a problem that the differential limiting force is insufficient under the usage conditions of recent high-torque engines.

In addition, differential limiting devices that use friction plates whose sliding surfaces are made of carbon fiber-reinforced carbonaceous composites have lower dynamic or static friction coefficients and relatively high dynamic friction coefficients, resulting in stake-slip and insufficient braking force. No problem arises. However, conventional carbon fiber-reinforced carbonaceous composites have a relatively large amount of wear, resulting in problems such as insufficient durability and complicated and expensive manufacturing.

Therefore, a technical object of the present invention is to provide a differential limiting device that is durable and does not cause stake-slip even in high-lux applications.

[Means for Solving the Problems] Therefore, in order to solve the above-mentioned problems, the present invention has been developed to reduce the friction of at least one of the first friction plate and the second friction plate of the differential limiting device. The carbon-71-wax has a structure in which carbon fibers or carbon fibers and inorganic microscopic bodies are integrally embedded in the carbon-71-wax. has a uniformly dense mosaic structure, and the ratio of the interface between the carbon fiber and the carbon 71 to lithics is 1 to the total interface.
0% or less and a density of 1.65 or more.

The differential limiting device of the present invention, like the conventional differential limiting device, has first friction plates and second friction plates arranged alternately overlapping each other. The second friction plate is integrally engaged with two relatively rotatable members of the differential in the rotational direction. In the differential limiting device of the present invention, at least one sliding surface of the friction plate is made of a special carbon fiber-reinforced carbon sintered body, which will be described in detail below. This carbon fiber-reinforced carbon sintered body has a structure in which carbon fibers or inorganic microscopic bodies made of carbon fibers, metals, and ceramics are integrally embedded in carbon 71 to carbon 71.
〜Rix has a mosaic structure in which optically anisotropic fine particles are evenly densely packed under a polarizing microscope. The peeled area is 10% or less.

The carbon fibers constituting this carbon fiber-reinforced carbon sintered body ensure the strength of the sintered body, and may be those that exhibit anisotropy or isotropy when viewed under a polarizing microscope. The carbon fibers may be cut short fibers or long fibers. Further, the carbon fibers may be oriented in a fixed direction or randomly oriented in the 71~rix. The blending ratio of carbon fiber in the carbon fiber-reinforced carbon sintered body is 2~
It is preferably 50% by weight, more preferably 10 to 40%.

The inorganic microscopic bodies that can be a component of the carbon fiber-reinforced carbon sintered body can be composed of microscopic metals and ceramics.

The shape of these inorganic microscopic bodies may be a powder, a strand, a fibrous shape such as a chair, a piece of foil, or the like. The blending ratio of inorganic fine particles in the carbon fiber reinforced carbon sintered body is preferably about 3.23% by weight.

The carbon 71~Rix, which is a component of the carbon fiber-reinforced carbon sintered body, has a mosaic structure in which fine particles with optical anisotropy are uniformly densely packed under a polarizing microscope. It is considered to have a structure in which carbon is regularly arranged in a certain direction. That is, this carbon matrix is in a state in which carbon particles having optical anisotropy are tightly packed together. Uniformly densely packed means that the carbon particles are not flowing and have no patterns such as flow lines. It is preferable that the carbon particles have a grain size of 30 μm or less, which can be observed as a saic pattern under a polarizing microscope.

The area of the peeled interface with respect to the total interface area between the carbon fibers and the carbon 71-lix constituting the carbon fiber-reinforced carbon sintered body of the present invention needs to be 10% or less.

If the carbon 71 to carbon fibers are separated from each other, the reinforcing effect of the carbon fibers will not be sufficient. Therefore, the peeled area of the interface may be 10% or less, preferably 3% or less of the total interface.

This separation between the carbon fiber and the carbon matrix can be observed and measured using a scanning electron microscope (hereinafter referred to as SEM).

Moreover, it is preferable that the porosity of this carbon fiber-reinforced carbon sintered body is 10% or more. The pores in this sintered body are observed as black dots when observed with a polarizing microscope. Therefore, the porosity can be calculated from the area of the black dots in the observed area.

The density of the carbon fiber reinforced carbon sintered body according to the present invention is 1.6
A value of 5 or more is a combination of characteristics such as the denseness of carbon 71 to wax, a small number of pores, and no peeling at the interface between the carbon fiber and the carbon matrix. Therefore, these matrices lack density, have too high porosity,
If there is a lot of separation between the fiber and the 71 helix, the specific gravity will be 1.
．． 65 or more.

The blending ratio of carbon fibers constituting this carbon fiber-reinforced carbon sintered body, the material and blending ratio of inorganic particles, the ratio of peeling area between carbon fibers and carbon 71 hexes, and the porosity are directly determined by this. This affects the mechanical strength and dynamic properties of carbon fiber-reinforced carbon sintered bodies. When the mechanical properties of this carbon fiber-reinforced carbon sintered body are defined by bending strength, it is preferable that the bending strength of this sintered body is 600 kQ/Cm 2 or more.

The carbon fiber-reinforced carbon sintered body of the present invention is a carbonaceous material having self-sintering properties in which uncarbonized carbon fibers or uncarbonized carbon fibers and inorganic microscopic bodies made of metal 'a'3 and xeramix are embedded. A sintered body obtained by sintering a composite body made of powder and powder can be used.

Here, the uncarbonized carbonaceous fiber refers to a carbonaceous fiber that has not been subjected to normal carbonization treatment. In other words, it refers to carbon fibers that have the potential to be coarsely carbonized by further heat treatment.Specifically, when raw pitch is used, the as-spun fibers or spun fibers are 5!l) Refers to fibers that have become infusible at a temperature not exceeding O'C.For polymeric fibers such as PAN (ponoacryloni-1-lyl)-based rayon, it refers to fibers that have undergone the decomposition process and have not yet been graphitized. Examples of this type of carbonaceous fiber include pitch fibers obtained by spinning coal-based or petroleum-based raw material pitch, and infusible fibers obtained by infusibleizing the same.

Spinning and infusibility of this raw material pitch may be carried out according to conventional methods, and conditions are not particularly limited.

Normally, pitch fibers are produced by feeding the raw grain to the spinning machine,
It can be obtained by heating it to about 300 to 400°C and extruding it from a nozzle under pressure with an inert gas. In addition, such pitch fibers are roughly oxidized to 1b in an oxidizing atmosphere.
It is possible to obtain infusible fibers by maintaining the temperature at about 0 to 500'c for about 0.5 to 5 hours. In addition, this raw material pitch is
It may be optically isotropic or optically anisotropic.

The fiber length of the uncarbonized carbonaceous fibers is not limited to short fibers or long fibers. However, in the case of short fibers, those having a diameter of 0.01 to 50 mm can be used. , especially 0.03 to 10
3.mm) is preferable from the viewpoint of ease of kneading and aspect ratio. If the length is long, the fibers become entangled with each other, resulting in poor dispersibility, resulting in poor isotropy of product properties, and 0.01 mIn J: 5. Rakuten ('A1 made crystal 0
This is not preferable because the strength suddenly decreases.

Further, the fiber diameter -C is preferably about 5 to 25 μn1. Furthermore, these fibers can also be used as nonwoven fabrics or coated fabrics.

The uncarbonized carbonaceous fibers are preferably surface-treated with a material containing a caking component such as tar, pitch, or organic polymer to improve compatibility with the binder. This surface treatment can be carried out by adding about 100 to 1000 parts by weight of caking component +A to 100 parts by weight of carbonaceous fibers, stirring, washing with an organic solvent, and drying.

The tar and pitch used for this surface treatment may be either coal-based or petroleum-based. When using pitch, heating to about 140 to 170°C is required during stirring, so tar is more preferable as a treatment material, and it also reduces the carbonization yield in the subsequent carbonization and graphitization steps. From this point of view, coal-based materials are more preferable.

Examples of organic polymers used for this surface treatment include enol resins, polyvinyl chloride, and polyvinyl alcohol.

The organic solvent used in this surface treatment cleaning may be an aromatic solvent such as toluene or xylene. Approximately 100 to 1000 parts by weight is added to 100 parts by weight of the mixture of the uncarbonized carbonaceous fiber and the material containing the adhesive component, and the mixture is stirred and washed.

This washing removes light oils containing many volatile components. The uncarbonized carbonaceous fibers that have been washed are dried under conditions such as heating and/or reduced pressure in a non-oxidizing atmosphere such as nitrogen or argon. The drying process is not limited to these methods as long as the organic solvent used for washing is removed.

Generally, the uncarbonized carbonaceous fibers that have been dried and surface-treated are subjected to a dispersion treatment, if necessary. However, since the dried fibers may be lumped or aggregated, in such a case, dispersion is carried out by any means such as a conventional powder mill, an atomizer, or a pulpizer.

The inorganic microscopic bodies together with the uncarbonized carbonaceous fibers serve as raw materials for the carbon fiber-reinforced carbon sintered body of the present invention. This inorganic microscopic body is
Depending on the intended use of the differential limiting device, the friction coefficient μ of the first friction plate and the second friction plate may be high and stable, or even if the friction coefficient μ is a relatively low value. It is added to provide high wear resistance or leakage. The inorganic fine particles have a melting point of 10000 or more and do not react with carbon, and more preferably have a melting point of 1-11000 or more.

Examples of such inorganic substances include inorganic oxides, inorganic carbides, inorganic nitrides, and inorganic borides.3 Examples of inorganic oxides include A, Q203, D102, and Z.
Mention may be made of rO2, MCl0, etc. Examples of inorganic carbides include B4C, TC, TaC, and ZrC.

Examples of inorganic nitrides include BN, 1-IN, Cr2
N, TaN, A32N, ZrN, etc. are too numerous to mention. Examples of inorganic borides include DineIB2, ZrB
2, B4 C, N + B, COB, BN, aB2, etc. can be mentioned. Furthermore, “eXMn, Mo
, N+, Nb, 5iSV, 10W, etc. can also be used. Note that these inorganic substances can also be added in the form of metals. In addition, as inorganic microscopic bodies,
Contains fine particulate matter such as Kusuka and ceramic fibers.

In order to select an appropriate one from the above-mentioned J: Una inorganic microscopic bodies, it is necessary to determine its friction coefficient μ, wear resistance properties, etc. according to the application and required characteristics of the differential limiting device. can be managed.

In particular, in order to make the coefficient of friction high,
It is preferable to employ oxides such as I 203 and MQO. In addition, when a friction coefficient of about 0.2 to 0.3 is preferable, TiC1/aC1/rC and TAN, △IN,
It is preferable to use carbide or nitride such as TaN. Conversely, if you want to lower the friction coefficient a little, use B
It is preferable to use a small amount of a boride such as 4C1B2, BN, or ZrB2.

1/1 When inorganic powder is used as the inorganic microparticles, the particle size should be 0.1, taking into consideration the compatibility with the 71~lix material, dispersibility, and the strength and abrasion resistance of the resulting sintered body. 5μIn
The thickness is preferably 0.2 to 4 μm, and more preferably 0.2 to 4 μm.

In addition, when inorganic fibers are used as inorganic particles (.J
2.71~Diameter 0.7~40μm, length 0゜01~Bmm, considering compatibility with wax material, dispersibility, strength and abrasion resistance of the completed sintered body, and separation of fibers. It is preferable to have a diameter of 1 to 15 μm and a length of 0 μm.
．． It is 05 to 3 mm.

The carbonaceous powder constitutes the binding material of the carbon fiber-reinforced carbon sintered body according to the present invention. This carbonaceous powder has self-sintering properties and is not carbonized or completely carbonized. This self-sintering '14F carbonaceous powder may be either petroleum-based or coal-based, and specifically includes mesocarbon microbeads, bulk mesophase pulverized products, low-temperature calcined coke pulverized products, etc. I can do it.

Among these, petroleum-based and coal-based Meccaphone microphones [
] Beads are preferable, and coal-based ones are more preferable from the viewpoint of carbonization yield. The self-sintering carbonaceous powder preferably has a particle size of 30 μm or less and a β-resin content of about 3 to 50%. The amount of β-resin is J, preferably 6 to 30%, more preferably 8 to 25%.

The sintered body according to the present invention can be manufactured by a simple process of dry mixing, dry molding, and firing as shown in FIG. 1, for example.

The charcoalized carbonaceous '4#I fiber, inorganic powder or inorganic fiber, and self-sintering carbonaceous powder are mixed and molded to form a composite. The mixing means at this time is not particularly limited, but in order to achieve uniform strength and wear resistance, it is preferable to mix the above-mentioned raw materials uniformly. In addition, the blending ratio of the self-sintering carbonaceous powder and the uncarbonized carbonaceous fiber is approximately 2 to 70 parts by weight per 100 parts by weight of the former, more preferably 2 to 70 parts by weight per 100 parts by weight of the former. The latter 10
Add about 50 parts by weight. Further, the amount of the inorganic fine particles added is preferably 3 to 30% by weight, and more preferably 5 to 10% by weight, based on the total weight of 100%.

In particular, when oxides are used as inorganic particles to increase the coefficient of friction, the amount of oxide powder or oxide fibers added is preferably 3 to 30% by weight, based on 100% by weight of the oxide. , more preferably 5 to 15% by weight.

The sintered body according to the present invention can be formed by a conventional method, and is usually formed into a predetermined shape under pressure of about 1 to 10 t On/Cff12;
The molding may be performed by the P method, the ITP method, the hot press method, or the like. Molding can be carried out at room temperature or under heating up to about 500'C in an inert atmosphere.

The composite body is sintered into a sintered body according to the present invention. Note that sintering here refers to carbonizing and solidifying the uncarbonized carbonaceous fibers and the self-sintering carbonaceous powder by firing at a temperature of about 700 to 1500'C under normal pressure. Note that, if necessary, this carbonized composite may be heated to a temperature higher than the sintering temperature in a graphitization furnace to graphitize it. The carbonization conditions are not particularly limited, but are usually heated in a non-oxidizing atmosphere at a rate of about 0.1 to 300'C/hour from room temperature to a temperature of about 1500 degrees Celsius for about 0.5 to 10 hours. Just wait and do it.

Note that even if d5 is reached during sintering, by sintering at a higher temperature, a part of the composite is carbonized and then graphitized.

Furthermore, the conditions for graphitization are not particularly limited, and the temperature is raised from the temperature during sintering to a temperature of about 1500 to 3000'C at a rate of about 0.1 to 500°C/hour in a non-oxidizing atmosphere. , all you have to do is wait for about 0.5 to 10 hours. When graphitization is performed, graphite crystals grow sufficiently and are oriented in an orderly manner, thereby further improving the density, strength, wear resistance, etc. of the product.

This special carbon fiber reinforced carbon sintered body is made by combining the composite before sintering with uncarbonized carbon fibers and inorganic powder or inorganic fibers.
It is composed of uncarbonized carbonaceous fibers and inorganic powder or charcoalized carbonaceous powder with self-sintering properties in which inorganic fibers are embedded. When the composite is sintered and covered, the carbonaceous fibers serving as the reinforcing material are uncarbonized or not completely carbonized, so they have self-sintering properties with the uncarbonized carbonaceous fibers. Uncarbonized carbonaceous powder has similar physical properties (strength, shrinkage rate, etc.) when carbonized. Therefore, the interfacial adhesion between these carbonaceous fibers and the carbonaceous powder is improved, and therefore high strength and excellent wear resistance can be obtained. In short, when sintering a composite, the uncarbonized carbon fibers and carbon powder shrink to the same degree and bond together, increasing their interfacial adhesion and increasing the strength and wear resistance of the friction plate. improves.

In addition, friction plates made of carbon fiber-reinforced carbon sintered bodies containing inorganic powder or inorganic fibers have a mechanical resistance force between them and other friction plates, which increases the friction coefficient μ. high,
It becomes stable. That is, since the added inorganic powder or inorganic fiber exerts a mechanical resistance force on the mating material, the friction coefficient μ of the one-volume part becomes high and stable.

For example, when inorganic powder is added, since it is necessarily in powder form, it becomes easier to separate from the carbon 71 to lix portion as the load increases, and the separation of this inorganic powder and the adhesion of the carbon 71 to lix portion are balanced. This makes the friction coefficient μ stable against changes in load. Further, when inorganic fibers are added, even if the load increases, since they are fibrous, they are difficult to separate from the carbon matrix portion, and therefore the friction coefficient μ becomes a high value.

In addition, as mentioned above, the self-sintering carbonaceous powder as a binder eliminates the need to use the conventional binder made of liquid carbonaceous material. There is no need to repeat impregnation and firing for filling, and the special carbon fiber-reinforced carbon sintered body according to the present invention can be filled using the simple steps of dry mixing, dry molding, and firing as shown in FIG. , can be manufactured at low cost.

The reason why the friction coefficient μ of sliding parts changes greatly depending on the inorganic powder or fiber added is thought to be because the state of the inorganic powder or fiber changes due to the heat generated by the movement. . For example, since oxides have high heat resistance, they leave their particle or fiber shapes during sliding, and are therefore thought to exhibit a high friction coefficient μ. Further, contrary to oxides, boride is thought to decompose and form a liquid phase due to heat during sliding, thereby lowering the coefficient of friction μ.

Generally speaking, when uncarbonized carbon fibers are surface-treated with a material containing a caking component such as tar, pitch, or organic polymer, the wettability of the carbon fiber interface increases, resulting in bonding and oxidation. Since the compatibility with the carbonaceous powder is increased, the interfacial adhesion between the carbonaceous fibers and the carbonaceous powder is further improved.

In the differential limiting device of the present invention, even if both the first friction plate and the second friction plate are made of the carbon fiber-reinforced carbon sintered body described above, one of the first friction plates and the second friction plate may be made of the carbon fiber-reinforced carbon sintered body. may be configured. Further, when both are composed of carbon 111i fiber-reinforced carbon sintered bodies, the type and blending ratio of the inorganic microscopic bodies to be blended can be made to be different. Also,
The first friction plate and the first friction plate are entirely made of the carbon fiber-reinforced carbon sintered body described above, and only the portion that becomes the sliding surface is made of the carbon fiber-reinforced carbon sintered body, The portion that provides strength, for example, the back plate portion, can be made of a structural material such as metal, resin, or ceramics.

The first friction plate and the second friction plate can be formed by directly forming into a predetermined shape by the method described above and sintering, or by making a block-shaped carbon ali fiber reinforced carbon sintered body and then shaping into a predetermined shape. It may be made by machining () to the dimensions.In addition, the first friction plate and the second friction plate made of a material other than the special carbon fiber reinforced carbon sintered body according to the present invention may be Other limited slip differential components may be the same as conventional limited slip differential components.

[Example] The present invention will be explained in detail below.

(Example 1) This example 1 configured as a differential car device
Fig. 2 shows a differential limiting device.

1 is a differential case, which rotates integrally with the final reduction gear (V in the figure). Inside the differential case 1, a pinion shaft 4 is arranged perpendicularly to the rotation axis of the case 1, and is integrally attached to the C1 differential goose 1. A pair of pinion keys t3.3- are rotatably supported on the shafts 1 to 1. 2.2' is Vinny A Yagya 3.3
As is well known, the inner spline 7 connects the left and right drive shafts (not shown).
are connected to each other. There is a space between the side wall of the differential case 1 and the back of the 1)-id case 2.2-.
A so-called multi-disc clutch a structure is provided. The multi-plate clutch mechanism is composed of a first friction plate 5a connected to the differential It has been arranged. When a differential movement of more than a predetermined value occurs between the left drive shaft due to the frictional force between the first friction plate 5a and the second friction plate 5b, a differential limiting action is performed as is well known.

The sliding surface of the first lug 1 5a of the differential limiting device of the first embodiment is formed of a carbon fiber-reinforced carbon sintered body, which will be described in detail below. The second friction plate is made of hardened and tempered steel plate (JIS 5K5) (Hv 450) with a surface roughness of 0.8μmR7, an outer diameter of 120mm, an inner diameter of 100mm, and a thickness of 1°8mm. did.

The first friction plate 5a has the shape shown in FIG. 3, and has carbon fiber-reinforced carbon sintered plates 1.0 mm thick made by the following method on both sides of a 1.0 mm thick steel plate substrate. A ring-shaped disc made of solid material is glued with glue.

In producing the carbon fiber-reinforced carbon sintered body, first, it consists of infusible fibers with a diameter of 15 μn and a length of 3 mm obtained by spinning from coal-based optically isotropic pitch using a conventional method. Uncarbonized carbonaceous fibers were prepared. After adding 900 parts by weight of self-sintering carbonaceous powder consisting of coal tar-based mesocarbon microbeads with a center particle size of 7 μm to 100 parts by weight of this uncarbonized carbonaceous fiber using the uncarbonized carbonaceous fiber as a reinforcing material, 21].

Molded with molding juice force of n/cm2, diameter 15cm height Q,
A 3 cm disc-shaped composite was formed.

Next, this composite was heated at 150°C in a non-oxidizing atmosphere.
The temperature was raised to 100°C at a rate of 1 hour, and the temperature was maintained for 1 hour for firing, thereby carbonizing and solidifying the uncarbonized carbonaceous fibers and self-sintering carbonaceous powder. Further, in a non-oxidizing atmosphere, at a rate of 500'C/hour - U゛2ε300'C
The mixture was heated to a temperature of 100.degree. C. and held for 20 minutes to graphitize it.

The thus prepared carbon fiber-reinforced carbon disk was machined to create a ring-shaped disk that stuck to the substrate.

A3. Using a part of this carbon fiber-reinforced carbon sintered body disk, the surface was observed using a polarizing microscope, the interface state between the 71~Rix and the reinforcing fibers was observed using a scanning electron microscope, and the density and bending strength were measured. When observed using a polarizing microscope,
The matrix or sintered carbon particles are observed in close contact with each other, and the individual particles are observed in a shining mosaic pattern with different color patterns, and the fibers are observed in the form of uniformly colored islands scattered throughout this matrix. It was done. In addition, black dots indicating pores were observed here and there. The area of these black dots is 10
When it was set as 0% by area, it was about 3% by area. The state of the interface between the 71-Rix and the reinforcing fibers observed with a scanning electron microscope showed that they were both integrally bonded, and no separation of the matrix and the reinforcing fibers was observed. In addition, the density of this carbon fiber reinforced carbon sintered body is 1.76
Ω/Cm3, and the bending strength was 9.3Ω/mm2.

The differential limiting device of Example 1 was installed in a car as a dino differential gear, and a driving test was conducted. In this test, no problems such as stake slip or abnormal wear were observed.

(Example 2) In place of the carbon fiber reinforced carbon sintered body forming the I sliding surface of the first friction plate of the differential limiting device of Example 1, carbon fiber reinforced carbon manufactured by the method described above was used. The first friction plate of Example 2 was made by attaching the sintered body to both sides of a substrate. Note that the other components of the differential limiting device are the same as those in the first embodiment.

In producing the carbon fiber-reinforced carbon sintered body according to Example 2, first, coal-based optically isotropic pitch was supplied to a spinner, heated to 340'C, and an inert sintered body was heated to 340'C. Vidge fibers obtained by extruding them from a nozzle under pressure are further held at 350°C for 2 hours in an oxidizing atmosphere to make them infusible. quality fiber was prepared. The total weight of 30% by weight of this infusible unsettled carbonaceous fiber as a reinforcing material and 70% by weight of rutal-based Mekkabon micropieces with a center particle diameter of 7 μm as a self-sintering carbonaceous powder is 05% by weight. %, add 5% by weight of alumina particles with a particle size of 0.5 μm, mix uniformly, and mix the resulting mixture at 2 ton/cm2.
The composite was molded at a molding pressure of 1 stomach.

Next, this composite was heated in a non-oxidizing atmosphere at normal pressure.
The temperature was raised to 1000'C at a rate of +O'C/hour and fired by holding at the same temperature for 1 hour to sinter and consolidate the uncarbonized carbonaceous fibers and self-sintering carbonaceous powder. and further 20°C at a rate of 500'C/hr in a non-oxidizing atmosphere.
It was heated to 00'C and held for 20 minutes for further sintering.

As a result, the carbon fiber-reinforced carbon sintered body according to Example 2 was obtained.

In addition, using a part of this carbon fiber-reinforced carbon sintered body block, as in Example 1, the surface observation using a polarizing microscope (J) and the interfacial state between the 71~Rix and the reinforcing fibers using a scanning electron microscope were conducted. I2 observation, density and bending strength were measured.

When observed using a polarizing microscope, the carbon particles sintered with 71 ~ lithics were observed to be closely adhered to each other in a mosaic pattern with individual particles shining in different color patterns, and the fibers were scattered throughout this matrix. A uniform color was observed in the form of islands, and alumina particles were observed in the form of white dots. In addition, black dots indicating pores were observed here and there. The area of these black dots was approximately 3% by area when the total area was taken as 100% by area. The state of the interface between the 71~Rix and the reinforcing fibers observed with a scanning electron microscope was such that the two were integrally bonded, and no separation of the 71~Rix and the reinforcing fibers was observed.

Furthermore, the density of this carbon fiber reinforced carbon sintered body is 1°76g.
/Cm3, and the bending strength was 8.5 kg/mm2.

The differential limiting device of Example 1 was used as a differential gear in an automobile, and a driving test was conducted. In this test, no problems such as differential slip or abnormal wear were observed.

(Test Example 1) To obtain an estimate of the friction coefficient and amount of wear between the first friction plate and the second friction plate used in the differential limiting device of the present invention, and the conventional differential limiting device. In order to compare the friction coefficient and the amount of wear between the first friction plate and the second friction plate of the device, a friction test was conducted using a sluth 1 to test machine. To Thrust 1, the test was always carried out by fixing the same first friction plate as used in the limited slip differential of the example to a rotary disk rotating at approximately 51''pm; For comparison, each friction plate was fixed to a non-rotating thrust plate, and the plate was pushed toward thrust 1, and the friction plates were applied 4
00 k Q-f was pressed for 1=1.0 hours to make one occupation, and the friction coefficient Jζ and the amount of wear at each time were measured. Note that the test from Slash 1 was carried out under oil lubrication using differential oil.

The friction plate of Comparative Example 1 was manufactured by the method described in Japanese Utility Model Application Publication No. 2-30530. As shown in Fig. 4, the friction plate is made of 40% by weight of rhizoane disulfide particles and 15% by weight of graphite particles formed by air spraying and heating hardening on a steel plate 13+ having an oil temperature of 12 in the vertical and horizontal directions on the surface. Thickness including 30%
A material with a surface film 14 of .mu.m is used (L).

The obtained results are summarized in FIGS. 5 and 6. Note that the white circles in FIG. 5 indicate the static friction coefficient, and the single-letter shapes indicate the dynamic friction coefficient. From FIG. 5, it can be seen that the friction plates used in the differential limiting device of this example all have a coefficient of dynamic friction higher than the coefficient of static friction, and have the same desirable characteristics as the friction plate of Comparative Example 1 as a differential limiting device. . Furthermore, the friction plate used in the differential limiting device of this example has a higher friction coefficient and less wear than the friction plates of Comparative Examples 1 and 2. Especially Example 2
It can be seen that the friction coefficient used in the differential limiting device has excellent characteristics with a high coefficient of friction and a small number of worn parts.

(Test Example 2) By variously changing the type and amount of Reramic as an inorganic microscopic body blended into the carbon fiber reinforced carbon sintered body used in Example 2, A test was conducted with the outer diameter of 351T)m and inner diameter of 31mm as the mating moon.
'l, 1lIll+ direction length 8.7mm SU J
Using a ring made of 2, with lubricating oil and 1 knot, the current SAF 5
Using W-30 base rail, at a rotational speed of 160 rpm, 15°7 mrT1 vertically on the outer circumferential surface of the opponent shrine.
A test piece with a width of 6.3mrn and a height of 10mm was loaded with a load of 15kQ.
7 (a), (b), (C), and (d) show the results at the 13° wear amount point. 71"02, BN has problems, but it can be seen that the combination of carbon fiber-reinforced carbon sintered body containing other inorganic particles and alloy steel is excellent.

In addition, in the above Example-C, the types of inorganic microscopic substances to be added were -, but it would be even better if, for example, one with excellent friction coefficient reduction and one with excellent wear resistance were mixed in an appropriate ratio. You will get some properties.

[Effects of the Invention] The differential limiting device of the present invention includes at least one of a first friction plate having a sliding LJ, a first friction plate having a braking function, and a second friction plate, or a special carbon fiber-reinforced carbon sintered plate. It is made by the body. This carbon fiber-reinforced carbon sintered body has the characteristics of a high coefficient of friction and a coefficient of dynamic friction that is higher than a coefficient of static friction, and an extremely small amount of wear. Therefore, the differential limiting device of the present invention does not suffer from the problem of T-slip or insufficient braking force. In addition, it has high durability due to less wear.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the manufacturing process of a special carbon fiber-reinforced carbon sintered body constituting the first friction member of the differential limiting device of the present invention, and FIG. 2 is a differential limiting device of Example 1. Figure 3 is a cross-sectional view of the main part of the first friction plate of Example 1] Figure n1, Figure 4
The figure is a plan view of the polishing plate of Comparative Example 2, Figures 5 a3 and 6.
The figures show the friction plate friction 1 of the nominal side tilt d3 and the comparative example.
Diagram showing the detection coefficient and amount of wear, Figure 7 (a), ([))
, (C) d3 and (d) [Fig. 1...Differential case 2...Reit gear A7 3...Pinion gear 4...
・Pinion shirt 1 to 5 days...First friction plate 5b...Second friction plate Patent applicant Toel Yu Jidosha Co., Ltd. Osaka Kawara 11 Noi Co., Ltd.

Claims (2)

[Claims] (1) A first friction plate and a second friction plate are arranged to be alternately overlapped, and the first friction plate and the second friction plate are two members of a differential gear that can rotate relative to each other. A differential limiting device that is integrally engaged in the rotational direction, and that at least one of the friction surfaces of the first friction plate and the second friction plate is made of a carbon fiber-reinforced carbonaceous composite. In the above, the carbon fiber-reinforced carbonaceous composite has a structure in which carbon fibers or carbon fibers and inorganic microscopic bodies are integrally embedded in a carbon matrix, and the carbon matrix is optically visible when viewed with a polarizing microscope. It has a mosaic structure in which anisotropic fine particles are uniformly densely packed, and the ratio of the interface between the carbon fiber and the carbon matrix that is separated is 1 to the total interface.
0% or less and a density of 1.65 or more. (2) The first friction plate and the second friction plate are arranged to be alternately overlapped, and the first friction plate and the second friction plate are two members of the differential gear that can rotate relative to each other. A differential limiting device that is integrally engaged in the rotational direction, and that at least one of the friction surfaces of the first friction plate and the second friction plate is made of a carbon fiber-reinforced carbonaceous composite. The carbon fiber-reinforced carbonaceous composite is obtained by sintering a composite consisting of uncarbonized carbonaceous fibers or uncarbonized carbonaceous fibers and carbonaceous powder having self-sintering properties in which inorganic microscopic bodies are embedded. 1. A differential limiting device comprising a carbon fiber-reinforced carbon sintered body obtained by