JP6796734B2 - Friction material manufacturing method and wet friction plate manufacturing method - Google Patents

Description

The present invention relates to a wet friction plate used in a lubricating oil, and in particular, is arranged between a prime mover and a driven body rotationally driven by the prime mover to transmit or block the driving force of the prime mover to the driven body. The present invention relates to a method for manufacturing a friction material suitable for a wet multi-plate clutch device and a method for manufacturing a wet friction plate .

Conventionally, in vehicles such as four-wheeled vehicles and two-wheeled vehicles, a wet multi-plate clutch device has been installed in order to transmit or shut off the rotational driving force of a prime mover such as an engine to a driven body such as wheels. Generally, in a wet multi-plate clutch device, rotational driving force is transmitted or cut off by pressing two plates arranged opposite to each other in lubricating oil against each other.

In this case, one of the two plates is composed of a wet friction plate in which a friction material is provided along the circumferential direction on the surface of a flat plate annular core metal. For example, Patent Document 1 below discloses a wet friction material (hereinafter referred to as "wet friction plate") in which a papermaking groove (hereinafter referred to as "lubricating oil recess") recessed in a concave shape is formed on the surface of the friction material. ing. As a result, the wet friction plate can easily discharge the lubricating oil adhering to the surface of the wet friction plate, and the drag torque can be reduced.

JP-A-2007-263203

However, in the wet friction plate described in Patent Document 1, the support layer of the lubricating oil recess into which the lubricating oil enters is compressed and deformed by press working or cutting to form the lubricating oil recess, so that the lubricating oil is discharged. The sex tends to be low. Therefore, in the conventional wet friction plate, there is a problem that the lubricating oil is difficult to be discharged especially when the lubricating oil is low temperature or when the contact pressure between the wet friction plate and the clutch plate is low.

The present invention has been made to address the above problems, and an object of the present invention is to provide a method for producing a friction material and a method for producing a wet friction plate, which can improve the discharge property of a lubricating oil adhering to the surface of the friction material. To do.

In order to achieve the above object, the feature of the present invention is that a friction sliding surface and a plurality of lubricating oil recesses recessed with respect to the friction sliding surface are formed on the surface of the porous layer having a plurality of cavities. In a wet friction plate provided with a friction material and a core metal formed in a flat plate annular shape in which the friction material is provided along the circumferential direction, the friction material has sharp corners or the like on the surface of the lubricating oil recess. It is formed on a smoothly continuous surface without any sharpened part of the shape, and the difference in the formation rate of the cavity between the porous layer forming the lubricating oil recess and the porous layer forming the friction sliding surface is ± 10. % in the der Rukoto below.

According to the feature of the present invention configured as described above, the wet friction plate is formed on the surface of the lubricating oil recess without any sharp portion having a sharp shape such as a corner, and is formed on a smoothly continuous surface and the lubricating oil. Since the porous layer forming the recess and the porous layer forming the friction sliding surface are formed at the same rate of formation of the cavity, the friction sliding surface and the lubricating oil recess lubricate the porous layer. The permeability and discharge of the oil are the same, and the discharge of the lubricating oil adhering to the surface of the friction material can be improved.

It should be noted that the fact that the porous layer forming the lubricating oil recess and the porous layer forming the frictional sliding surface have the same cavity formation rate does not mean only perfect agreement between the two. Difference in formation rate (for example, difference of ± 10% or less) within a predetermined range (for example, difference of ± 10% or less) in which the difference in permeability and discharge of lubricating oil can be regarded as substantially the same. ) Is included. Further, the smoothly continuous surface forming the surface of the lubricating oil recess may include an inclined surface formed of a plane extending linearly, but it is preferably formed by a curved surface recessed in a concave shape.

Another feature of the present invention is that in the wet friction plate, the lubricating oil recesses are formed in an arc shape having at least one cross section of at least one of two directions orthogonal to each other in a plan view. is there.

According to another feature of the present invention configured in this way, in the wet friction plate, at least one cross section of the lubricating oil recesses in two directions orthogonal to each other in a plan view is formed in an arc shape having one curvature. Therefore, the lubricating oil recess can be easily formed.

Further, another feature of the present invention is that in the wet friction plate, the lubricating oil recess is formed in an elongated hole shape or an elliptical shape in a plan view.

According to another feature of the present invention configured in this way, the wet friction plate is locally formed in the friction sliding surface because the lubricating oil recess is formed in a bottomed elongated hole shape or an elliptical shape in a plan view. It is possible to form the lubricating oil recess while securing the required frictional contact area without causing a large missing portion of the frictional sliding surface.

Another feature of the present invention, in the wet friction plate, lubricating oil recess is to lubricating oil recess adjacent to each other while being formed to extend in a straight line is formed in the direction orthogonal to each other ..

According to another feature of the present invention configured in this way, the wet friction plate is formed so that the lubricating oil recesses extend linearly and the lubricating oil recesses adjacent to each other extend in a direction orthogonal to each other. Therefore, it is possible to prevent the durability of the friction material from weakening in a specific direction, and it is possible to ensure uniform durability. Further, the lubricating oil recess can be formed in the direction intersecting the rotational drive direction of the wet friction plate to improve the frictional resistance, and is formed so as to extend outward in the radial direction of the wet friction plate. It is also possible to ensure the discharge property of the lubricating oil due to the centrifugal force.

Further, another feature of the present invention is that in the wet friction plate, the lubricating oil recesses are formed at a plurality of depths.

According to another feature of the present invention configured in this way, in the wet friction plate, since the lubricating oil recesses are formed at a plurality of depths, the friction material is worn out and the thickness of the entire friction material is increased. When it becomes thin, the shallow lubricating oil recesses are almost extinguished, and it is possible to suppress a decrease in the durability of the friction material. In this case, the wet friction plate can be expected to have the same effect by forming the lubricating oil recesses at a plurality of types of depths, or by forming the lubricating oil recesses at a plurality of types of groove widths.

Further, the present invention can be implemented not only as an invention of a wet friction plate, but also as an invention of a wet multi-plate clutch provided with the wet friction plate and a method for manufacturing the wet friction plate.

Specifically, in a wet multi-plate clutch device, a wet multi-plate clutch device is driven to rotate between both by arranging facing plates facing each other through a gap and lubricating oil on a driving side plate that is rotationally driven by a prime mover and bringing them into close contact with each other or separated from each other. In a wet multi-plate clutch device that transmits or disengages force, at least one of the driving side plate and the opposing side plate is the wet friction plate according to any one of claims 1 to 5. Good. According to the wet multi-plate clutch device configured as described above, the same effect as that of the wet friction plate can be expected.

Further, in the method of manufacturing a wet friction plate, a friction sliding surface and a plurality of lubricating oil recesses recessed with respect to the friction sliding surface are formed on the surface of a porous layer having a plurality of cavities. A method for manufacturing a wet friction plate including a material and a core metal formed in a flat plate annular shape and having a friction material provided along the circumferential direction, in the form of a slurry containing a fiber material constituting a porous layer. An original forming step of molding the raw material into a sheet, a water content adjusting step of reducing the water content of the sheet-shaped raw material to 90% or less and 50% or more, and a sheet-shaped raw material having an adjusted water content with a corner on the surface. A step of forming a lubricating oil recess by pressing a lubricating oil concave molding mold formed on a smoothly continuous surface without a sharp portion having a sharp shape such as a portion, and a sheet in which a lubricating oil concave is formed. It is preferable to include a drying step of reducing the water content of the raw material to 10% or less. According to the method for manufacturing a wet friction plate configured as described above, the wet friction plate can be manufactured.

It is sectional drawing which shows the whole structure of the wet multi-plate clutch apparatus provided with the wet friction plate which concerns on one Embodiment of this invention. It is a top view which outlines the appearance of the wet friction plate which concerns on one Embodiment of this invention incorporated in the wet multi-plate clutch apparatus shown in FIG. This is image data obtained by capturing a cross section of a friction material constituting the wet friction plate shown in FIG. 2 with a scanning electron microscope. (A) to (C) schematically show the lubricating oil recesses in the friction material constituting the wet friction plate shown in FIG. 2, (A) is a plan view of the lubricating oil recesses, and (B) is a lubricating oil. It is a cross-sectional view of a recess, and (C) is a vertical cross-sectional view of a lubricating oil recess. (A) and (B) are image data obtained by binarizing the image data trimmed by the trimming frames TF1 and TF2 with respect to the image data shown in FIG. 3, and (A) is the porosity directly under the friction sliding surface. The layer is shown, and (B) shows the porous layer just below the lubricating oil recess. FIG. 5 is a bar graph showing the formation rate of cavities in the friction material shown in FIG. 5 and the formation rate of cavities in the friction material according to the prior art for each friction sliding surface and lubricating oil recess. This is image data obtained by capturing a cross section of a friction material according to a conventional technique with a scanning electron microscope. (A) and (B) are image data obtained by binarizing the image data trimmed by the trimming frames TF1 and TF2 with respect to the image data shown in FIG. 7, and (A) is the porosity directly under the friction sliding surface. The layer is shown, and (B) shows the porous layer just below the lubricating oil recess. It is explanatory drawing which shows typically the main manufacturing process of the wet friction plate and friction material shown in FIG. 9 is a partially enlarged view schematically showing an external configuration of a lubricating oil recess molding mold attached to the press roller shown in FIG. 9. It is a partial plan view which shows a part of the appearance structure of the wet friction plate which concerns on the modification of this invention. It is a partial plan view which shows a part of the appearance structure of the wet friction plate which concerns on other modification of this invention. It is a partial plan view which shows a part of the appearance structure of the wet friction plate which concerns on other modification of this invention. It is a partial plan view which shows a part of the appearance structure of the wet friction plate which concerns on other modification of this invention.

Hereinafter, an embodiment of a wet friction plate according to the present invention, a wet multi-plate clutch device provided with the wet friction plate, and a method for manufacturing the wet friction plate will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing an outline of the overall configuration of a wet multi-plate clutch device 100 provided with a wet friction plate 200 according to the present invention. It should be noted that each of the figures referred to in the present specification is schematically shown by exaggerating some of the components in order to facilitate the understanding of the present invention. Therefore, the dimensions and ratios between the components may be different. The wet multi-plate clutch device 100 is a mechanical device for transmitting or blocking the driving force of an engine (not shown) which is a prime mover in a two-wheeled vehicle (motorcycle) to wheels (not shown) which are driven objects. It is placed between the engine and the transmission (not shown).

(Structure of Wet Multi-Plate Clutch Device 100)
The wet multi-plate clutch device 100 includes a housing 101 made of an aluminum alloy. The housing 101 is formed in a bottomed cylindrical shape, and is a member that constitutes a part of the housing of the wet multi-plate clutch device 100. An input gear 102 is fixed to the left side surface of the housing 101 by a rivet 102b via a torque damper 102a. The input gear 102 is rotationally driven by meshing with a drive gear (not shown) that is rotationally driven by driving the engine. A plurality of clutch plates 103 (8 in this embodiment) are spline-fitted on the inner peripheral surface of the housing 101 in a state where they can be displaced along the axial direction of the housing 101 and can rotate integrally with the housing 101. Each is held by.

The clutch plate 103 is a flat plate annular part pressed against the wet friction plate 200 described later, and is formed by punching a thin plate material made of SPCC (cold rolled steel plate) material in an annular shape. On both side surfaces (front and back surfaces) of these clutch plates 103, oil grooves (not shown) having a depth of several μm to several tens of μm for holding the lubricating oil described later are formed. Further, each side surface (front and back surface) of the clutch plate 103 in which the oil groove is formed is subjected to surface hardening treatment for the purpose of improving wear resistance. Since this surface hardening treatment is not directly related to the present invention, the description thereof will be omitted.

Inside the housing 101, a friction plate holder 104 formed in a substantially cylindrical shape is arranged concentrically with the housing 101. A large number of spline grooves are formed on the inner peripheral surface of the friction plate holder 104 along the axial direction of the friction plate holder 104, and the shaft 105 fits into the spline grooves. The shaft 105 is a shaft body formed in a hollow shape, and one end side (on the right side in the drawing) rotatably supports the input gear 102 and the housing 101 via a needle bearing 105a, and a friction plate for spline fitting. The holder 104 is fixedly supported via the nut 105b. That is, the friction plate holder 104 rotates integrally with the shaft 105. On the other hand, the other end (left side in the drawing) of the shaft 105 is connected to a transmission (not shown) in a two-wheeled vehicle.

A shaft-shaped push rod 106 is arranged through the hollow portion of the shaft 105 so as to protrude from the one (right side in the drawing) end of the shaft 105. The push rod 106 is connected to a clutch operating lever (not shown) on the shaft 105 on the opposite side (left side in the drawing) protruding from one end (on the right side in the drawing), and by operating the clutch operating lever. It slides in the hollow portion of the shaft 105 along the axial direction of the shaft 105.

On the outer peripheral surface of the friction plate holder 104, a plurality of (7 in this embodiment) wet friction plates 200 can be displaced along the axial direction of the friction plate holder 104 with the clutch plate 103 sandwiched between them. In addition, they are held by spline fitting in a state where they can rotate integrally with the friction plate holder 104.

On the other hand, the inside of the friction plate holder 104 is filled with a predetermined amount of lubricating oil (not shown), and three tubular support columns 104a are formed (only one is shown in the figure). The lubricating oil is supplied between the wet friction plate 200 and the clutch plate 103 to prevent absorption of frictional heat generated between the wet friction plate 200 and the clutch plate 103 and wear of the friction material 210.

Further, the three tubular support columns 104a are each formed in a state of protruding toward the outside in the axial direction (right side in the drawing) of the friction plate holder 104, and the pressing covers are arranged at positions concentric with the friction plate holder 104. 107 is assembled via a bolt 108a, a receiving plate 108b, and a coil spring 108c, respectively. The pressing cover 107 is formed in a substantially disk shape having an outer diameter substantially the same as the outer diameter of the wet friction plate 200, and is pressed toward the friction plate holder 104 by the coil spring 108c. A release bearing 107a is provided at the inner center of the pressing cover 107 at a position facing the right end of the push rod 106 in the drawing.

(Structure of Wet Friction Plate 200)
As shown in FIG. 2 in detail, the wet friction plate 200 is configured to include an oil groove 203 and a friction material 210 on a flat plate annular core metal 201, respectively. The core metal 201 is a member that serves as a base of the wet friction plate 200, and is formed by punching a thin plate material made of an SPCC (cold rolled steel plate) material in a substantially annular shape. In this case, an internal tooth-shaped spline 202 for fitting the spline with the friction plate holder 104 is formed on the inner peripheral portion of the core metal 201.

On the side surface of the wet friction plate 200 facing the clutch plate 103, that is, the side surface of the core metal 201 facing the clutch plate 103, a plurality of (32 pieces in this embodiment) small pieces of friction material 210 are formed. Each is provided via an oil groove 203 formed of a gap along the circumferential direction of the core metal 201.

The oil groove 203 is a flow path for guiding the lubricating oil between the inner peripheral edge and the outer peripheral edge of the core metal 201 of the wet friction plate 200, and the lubricating oil is allowed to exist between the wet friction plate 200 and the clutch plate 103. It is also an oil holding part for storing. The oil groove 203 is formed so as to extend linearly between each of the plurality of small pieces of friction material 210.

The friction material 210 improves the frictional force with respect to the clutch plate 103, and is made of a small piece of paper material attached along the circumferential direction of the core metal 201. As shown in FIG. 3, the friction material 210 is composed of a hard porous layer 211 in which a paper base material is impregnated with a thermosetting resin and cured.

In this case, the paper base material is constructed by adding a filler to at least one of the organic fiber and the inorganic fiber. Here, the organic fibers include wood pulp, synthetic pulp, polyester fiber, polyamide fiber, polyimide fiber, polyvinyl alcohol-modified fiber, polyvinyl chloride fiber, polypropylene fiber, polybenzoimidazole fiber, acrylic fiber, carbon fiber, and phenol. Fibers, nylon fibers, cellulose fibers and the like can be composed of one or more kinds. The inorganic fibers include glass fibers, rock wool, potassium titanate fibers, ceramic fibers, silica fibers, silica-alumina fibers, kaolin fibers, bauxite fibers, kayanoid fibers, boron fibers, magnesia fibers and metal fibers. It can be composed of multiple types.

The filler also functions as a friction modifier and / or a solid lubricant, and contains barium sulfate, calcium carbonate, magnesium carbonate, silicon carbide, boron carbide, titanium carbide, silicon nitride, boron nitride, and alumina. , Silica, zirconia, cashew dust, rubber dust, diatomaceous earth, graphite, talc, kaolin, magnesium oxide, molybdenum disulfide, nitrile rubber, acrylonitrile-butadiene rubber, styrene butadiene rubber, silicone rubber and fluorine rubber. Can be configured. Further, examples of the thermosetting resin include phenolic resin, melamine resin, epoxy resin, urea resin and silicone resin.

Innumerable cavity portions 212 are formed in the porous layer 211. The cavity 212 is a pore portion formed in a gap between each material of the paper base material and the thermosetting resin in the absence of the paper base material and the thermosetting resin, and the lubricating oil adhering to the surface of the friction material 210 is present. It is the part that penetrates and flows or is retained. A large number of the hollow portions 212 are randomly formed in the porous layer 211 in various sizes. In this case, the cavity 212 includes a cavity 212 that opens to the surface of the porous layer 211 and a cavity 212 that is formed inside the porous layer 211 without facing the surface of the porous layer 211. .. Further, the cavity portion 212 includes a case where the cavity portions 212 adjacent to each other communicate with each other and a case where the cavity portions 212 adjacent to each other do not communicate with each other.

As shown in FIGS. 4A to 4C, a friction sliding surface 213 and a lubricating oil recess 214 are formed on the surface of the porous layer 211, respectively. The friction sliding surface 213 is a portion that comes into contact with the clutch plate 103 and frictionally slides, and is composed of a flat surface. The lubricating oil recesses 214 are portions that increase the frictional resistance of the friction material 210 and hold the lubricating oil, and are formed in a plurality of recessed portions with respect to the friction sliding surface 213. In this case, the recessed surface of each lubricating oil recess 214 is formed as a smoothly continuous surface without sharpened portions having a sharp shape such as corners.

In the present embodiment, each lubricating oil recess 214 is formed in a long hole shape in a plan view. More specifically, the lubricating oil recess 214 has a vertical cross-sectional shape along the longitudinal direction in which the deepest portion extends linearly in the horizontal direction, and both ends of the deepest portion are gently curved toward the friction sliding surface 213. It is formed in a curved shape. Further, the lubricating oil recess 214 has an arcuate cross-sectional shape along the width direction orthogonal to the longitudinal direction. In this case, the lubricating oil recess 214 is configured to include a plurality of sizes of lubricating oil recesses 214 formed by a plurality of types of longitudinal lengths, width directions, and deepest depths. .. In the present embodiment, the lubricating oil recess 214 has a plurality of types having a longitudinal direction of about 1.0 to 2.0 mm, a width direction of about 0.6 to 0.7 mm, and a depth of 0.25 to 0.4 mm. It is composed of sizes.

Further, these lubricating oil recesses 214 are formed in a direction in which the lubricating oil recesses 214 adjacent to each other extend in a direction orthogonal to each other via the friction sliding surface 213. In the present embodiment, the lubricating oil recess 214 is formed so that the lubricating oil recesses 214 adjacent to each other in the longitudinal direction and the width direction extend in directions orthogonal to each other. That is, in the present embodiment, the lubricating oil recess 214 is formed in a mesh shape on the entire surface of the friction sliding surface 213 in a plan view.

In the porous layer 211, the hollow portion 212 is formed at the same formation rate in the portion forming the friction sliding surface 213 and the portion forming the lubricating oil recess 214. Here, the formation rate of the cavity portion 212 is the ratio of the cavity portion 212 occupied in a certain space in the porous layer 211. The formation rate of the cavity 212 can be calculated from the amount of fluid injected by pressure-injecting a fluid such as oil, mercury or helium into the porous layer 211. Further, the formation rate of the cavity portion 212 can be approximately calculated by image processing using a digital image obtained by imaging the porous layer 211. Specifically, the formation rate of the cavity portion 212 is obtained by acquiring an image of each cross section of the porous layer 211 directly below the friction sliding surface 213 and the porous layer 211 directly below the lubricating oil recess 214. It can be calculated by image processing to be binarized.

First, the operator cuts the lubricating oil recess 214 in the friction material 210 in the cross-sectional direction, and then uses a magnifying image device such as a scanning electron microscope to measure the state of this cross section at a predetermined magnification (for example, 120 times). The digital image data (hereinafter, simply referred to as “image data”) captured in 1 is acquired (see FIG. 3). In this case, the operator takes an image including the cross section of the friction sliding surface 213 formed around the lubricating oil recess 214 to be imaged.

Next, the worker can process the image data, and in the image data acquired by using a computer device such as a personal computer, the image data of the portion directly below the lubricating oil recess 214 and the image of the portion directly below the friction sliding surface 213. The data is trimmed by the trimming frames TF1 and TF2 having a predetermined size, respectively. In this case, the trimming frame TF1 that defines the trimming range of the image data of the portion directly below the lubricating oil recess 214 is centered on the center position in the width direction of the lubricating oil recess 214 in the portion directly below the lubricating oil recess 214. It can be formed in a square shape as a whole with a length of at least 1/3 or more within the width of the above and at least 70% or more within the thickness of the porous layer 211 immediately below the lubricating oil recess 214. ..

On the other hand, the trimming frame TF2 that defines the trimming range of the image data of the portion directly below the friction sliding surface 213 has the same size as the trimming frame TF1 and is sufficiently separated from the lubricating oil recess 214. It is placed directly under the. In these cases, the trimming frames TF1 and TF2 are arranged at positions close to the surfaces of the lubricating oil recess 214 and the friction sliding surface 213. In this embodiment, the trimming frames TF1 and TF2 are formed by 330 pixels × 660 pixels.

Next, as shown in FIGS. 5A and 5B, the operator uses image processing software (known computer program) capable of binarizing the image data in the trimming frames TF1 and TF2. The two trimmed image data are binarized. In this case, the image processing software is set with a threshold value capable of accurately converting the image data representing the cavity 212 in the image data into black or white. As a result, the operator can acquire the image data obtained by binarizing the image data representing the portions directly below the lubricating oil recess 214 and the friction sliding surface 213. In the present embodiment, the cavity 212 is converted to black and the porous layer 211 other than the cavity 212 is converted to white.

Next, the worker uses image processing software (a known computer program) that can calculate each area of the black portion and the white portion in the binarized image data, and the cavity portion in the binarized image data. The total value obtained by integrating the areas of the portion (black portion) corresponding to 212 is calculated. The calculation of this total value is performed for each trimming frame TF1 and TF2.

As a result, the operator can set the difference between the total area of the cavity 212 in the trimming frame TF1 on the image data and the total area of the cavity 212 in the trimming frame TF2 on the image within a predetermined range. If the formation rate is the same. Here, the difference within a predetermined range is preferably such that the difference between the two total values is within a range of ± 10%. The worker may refer to the ratio of the total area of the cavity 212 to the total area of the trimming frame TF1 or the total area of the porous layer 211 (white portion) excluding the cavity 212 in the trimming frame TF1. It is also possible to confirm the identity of the formation rate by comparing the ratio of the total value of the areas of the cavities 212 with the ratio of the total values of the similar areas in the trimming frame TF2.

Here, the verification results by the present inventors will be described. FIG. 6 is a bar graph showing the integrated value of the area of the cavity 212 obtained by performing the above-mentioned binarized image processing on the friction material 210 according to the present invention and the friction material 90 according to the prior art. Here, the horizontal axis is the total area of the friction sliding surface 213 of the friction material 210 and each cavity 212 of the lubricating oil recess 214, and each cavity of the friction sliding surface 93 and the lubricating oil recess 94 of the friction material 90. It is the total value of the area of 92. The vertical axis is the ratio of the total area of the cavity 212 to the total area of the trimming frames TF1 and TF2.

Further, as shown in FIG. 7, the friction material 90 has a concave lubricating oil recess 94 formed by pressing a mold against the surface of the porous layer 91 having the same quality as the porous layer 211. In this case, the lubricating oil recesses 94 are formed with corners having an angle of about 120 ° at both ends in the cross-sectional direction at the bottom. In FIG. 7, only one of the two corners (left side in the drawing) is imaged, but the corner on the other side that is not imaged is formed at the right end in the image. ing.

With respect to the friction material 90, the present inventors acquired image data obtained by imaging the porous layer 91 in the same manner as the friction material 210, and then, as shown in FIG. 8, with respect to the acquired image data. Trimming is performed with the trimming frames TF1 and TF2 to binarize. Then, in the same manner as described above, the present inventors calculate the total value obtained by integrating the areas of the portions (black portions) corresponding to the hollow portions 92 in the binarized image data. From the image data shown in FIGS. 7 and 8, the friction material 90 is a porous layer in which the porous layer 91, which is a support layer forming the lubricating oil recess 94, is a support layer forming the friction sliding surface 93. It can be confirmed that the material is compressed and crushed in the vertical direction shown above.

According to the verification results by the present inventors, the formation rate of the cavity 212 in the friction material 210 directly under the friction sliding surface 213 is 27.4%, and the cavity 212 directly under the lubricating oil recess 214 The formation rate is 26.1%. Further, the formation rate of the cavity portion 92 directly below the friction sliding surface 93 in the friction material 90 is 28.8%, and the formation rate of the cavity portion 92 directly below the lubricating oil recess 94 is 21.2%. .. Each of these formation rates is an average value of a plurality of samples.

(Manufacturing of wet friction plate 200)
Next, a method of manufacturing the wet friction plate 200 configured as described above will be described with reference to FIGS. 9 and 10. First, the worker carries out a raw material stirring step of stirring the raw materials. Specifically, the operator puts the raw material of the paper base material, that is, the organic fiber and / or the inorganic fiber, the filler and the coagulant into the water in the stirring tank 300 and stirs the slurry. Produces raw material. Next, the operator transfers the slurry-like raw material in the stirring tank 300 to the papermaking tank 301 using the pump 300a.

Next, the worker carries out the papermaking process. This manufacturing process is mainly composed of an original forming process, a water content adjusting process, a lubricating oil recess forming process, and a drying process. Specifically, the operator rotationally drives the transport device 303 provided with the endless belt-shaped papermaking net 302 arranged so as to face the papermaking tank 301, and filters the raw material from the papermaking tank 301 into a sheet shape. It is conveyed to a pair of press rollers 305 (original forming process). The transport device 303 is provided with a water absorption roller 304a and a suction box 304b between the papermaking tank 301 and the press roller 305, respectively, and removes water from the sheet-shaped raw material on the papermaking net 302 (moisture content adjusting step).

The press roller 305 is a component for forming the lubricating oil recess 214 into the sheet-shaped raw material on the papermaking net 302, and is composed of a pair of rollers arranged so as to face each other. In this case, as shown in FIG. 10, a lubricating oil recess forming mold 305a in which metal or resin threads are knitted in a grid pattern is formed on the surface of one of the two rollers constituting the press roller 305. It is composed by being wrapped. The press roller 305 is provided with the water content (% by weight) of the sheet-shaped raw material on the path of the papermaking net 302 within the range of 90% to 50%. In the present embodiment, the press roller 305 is provided with the water content (% by weight) of the sheet-shaped raw material on the path of the papermaking net 302 within the range of 60% to 50%.

Therefore, the sheet-shaped raw material that has been pulled up from the papermaking tank 301 and adjusted to a predetermined water content is passed through the press roller 305 to bring the friction sliding surface 213 and lubrication to the surface facing the lubricating oil recess molding mold 305a. Oil recesses 214 are formed respectively (lubricating oil recess molding step). In this case, the sheet-shaped raw material is adjusted to a relatively high water content, and the lubricating oil recess molding mold 305a is formed on a smooth curved surface. As a result, the friction material 210 is prevented from being compressed and deformed at the portion where the lubricating oil recess molding mold 305a is pressed and the hollow portion 212 disappearing. Therefore, the friction sliding surface 213 and the lubricating oil recess 214 are porous. It is possible to suppress a difference in the formation rate of the cavity portion 212 in the layer 211. According to the experiments conducted by the present inventors, it is easier to secure flexibility in the lubricating oil recess molding mold 305a as compared with the case where the lubricating oil recess molding mold 305a is made of metal by knitting a resin thread. It is possible to suppress compressive deformation of the porous layer 211 directly under 214.

Next, the sheet-shaped raw material on which the friction sliding surface 213 and the lubricating oil recess 214 are formed is passed through a drying device 306 composed of a drying roller or the like arranged on the downstream side of the press roller 305. Further, the water content is reduced to 10% or less (drying step). In this case, the water content of the sheet-shaped raw material in which the lubricating oil recesses 214 are formed is preferably 3% or more. After that, the sheet-shaped raw material is wound around the recovery roller 307 to complete the papermaking process.

Next, the operator carries out a curing step. Specifically, the worker impregnates the sheet-shaped raw material dried to a moisture content of 10% or less with a thermosetting resin, and then presses the sheet-shaped raw material while heating to adjust the shape. Let it cure. As a result, the operator can manufacture the friction material 210 made of the porous layer 211 that has been cured with the friction sliding surface 213 and the lubricating oil recess 214 formed respectively.

Next, the operator carries out a step of attaching the friction material 210. Specifically, the operator attaches a small piece of the friction material 210 along the circumferential direction to the surface of the core metal 201 manufactured by machining such as press working in another process using an adhesive. In this case, the operator may attach the friction material 210 previously cut into small pieces to the core metal 201, or may cut the friction material 210 into small pieces when attaching to the core metal 201. .. As a result, the operator can manufacture the wet friction plate 200 in which the small piece-shaped friction material 210 is attached to both sides of the core metal 201 along the circumferential direction through the oil groove 203. In the manufacturing process of the wet friction plate 200, there are a machining process, a friction characteristic adjusting process, an inspection process, and the like other than those described above, but the description thereof will be omitted because they are not directly related to the present invention.

(Operation of wet friction plate 200)
Next, the operation of the wet friction plate 200 configured as described above will be described. The wet friction plate 200 is assembled and used in the wet multi-plate clutch device 100 as described above. As described above, the wet multi-plate clutch device 100 is arranged between the engine and the transmission in the vehicle, and the driving force of the engine is changed by operating the clutch operating lever by the operator of the vehicle. Transmit and shut off to the aircraft.

That is, when the vehicle operator (not shown) operates the clutch operating lever (not shown) to retract the push rod 106 (displaced to the left in the figure), the tip of the push rod 106 is a release bearing. The 107a is not pressed, and the pressing cover 107 presses the clutch plate 103 by the elastic force of the coil spring 108c. As a result, the clutch plate 103 and the wet friction plate 200 are in a state of being pressed against each other and frictionally connected while being displaced toward the receiving portion 104b formed in a flange shape on the outer peripheral surface of the friction plate holder 104. As a result, the driving force of the engine transmitted to the input gear 102 is transmitted to the transmission via the clutch plate 103, the wet friction plate 200, the friction plate holder 104, and the shaft 105.

On the other hand, when the operator of the vehicle operates the clutch operating lever (not shown) to move the push rod 106 forward (displaced to the right in the figure), the tip of the push rod 106 presses the release bearing 107a. The pressing cover 107 is displaced to the right side in the drawing while resisting the elastic force of the coil spring 108c, and the pressing cover 107 and the clutch plate 103 are separated from each other. As a result, the clutch plate 103 and the wet friction plate 200 are displaced from each other while being displaced toward the pressing cover 107, and are released from being connected to each other and separated from each other. As a result, the driving force is not transmitted from the clutch plate 103 to the wet friction plate 200, and the transmission of the driving force of the engine transmitted to the input gear 102 to the transmission is cut off.

In a state where the clutch plate 103 and the wet friction plate 200 are in frictional contact, the lubricating oil existing on the surface of the friction material 210 in the wet friction plate 200 is pushed by the clutch plate 103 and a part of the friction material 210 is pressed. It is discharged to the outside of the friction material 210 through the outer edge portion, and a part of the other part permeates into the friction material 210. In this case, the lubricating oil that permeates into the friction material 210 includes the lubricating oil that is held in the lubricating oil recess 214 and the lubricating oil that permeates into the porous layer 211. Then, a part of the lubricating oil that permeates into the porous layer 211 is discharged from the end face of the porous layer 211 (friction material 210) through the cavity portion 212, and a part of the other part stays in the cavity portion 212. ..

In this case, the lubricating oil recess 214 is formed on a surface that holds the lubricating oil without any sharp portion having a sharp shape such as a corner, and is formed on a smoothly continuous surface, and is a porous layer constituting the lubricating oil recess 214. The formation rate of the cavity 212 is the same between the 211 and the porous layer 211 forming the friction sliding surface 213. As a result, in the wet multi-plate clutch device 100, the difference in the permeability and discharge of the lubricating oil with respect to the porous layer 211 between the friction sliding surface 213 and the lubricating oil recess 214 is reduced, and the wet multi-plate clutch device 100 adheres to the surface of the friction material 210. It is possible to improve the discharge property of the lubricating oil, stabilize the temperature characteristics (cooling characteristics) and the surface pressure characteristics, and improve the durability of the friction material 210.

Further, in the wet multi-plate clutch device 100, when the clutch plate 103 and the wet friction plate 200 are separated from each other, the amount of lubricating oil remaining between the clutch plate 103 and the wet friction plate 200 is smaller than that in the prior art. As a result, the wet multi-plate clutch device 100 can reduce the drag torque in a state in which the two are indirectly connected by the lubricating oil existing between the clutch plate 103 and the wet friction plate 200 when the clutch is off. it can.

As can be understood from the above operation description, according to the above embodiment, the wet friction plate 200 is formed on the surface of the lubricating oil recess 214 so as to have a smoothly continuous surface without sharp portions having a sharp shape such as corners. At the same time, the porous layer 211 forming the lubricating oil recess 214 and the porous layer 211 forming the friction sliding surface 213 are formed at the same rate of formation of the cavity 212, so that the friction sliding surface is formed. The permeability and discharge of the lubricating oil to the porous layer 211 are the same in the 213 and the lubricating oil recess 214, and the discharge of the lubricating oil adhering to the surface of the friction material 210 can be improved.

Furthermore, the practice of the present invention is not limited to the above-described embodiment, and various changes can be made as long as the object of the present invention is not deviated. In each of the modifications shown below, the same components as the wet friction plate 200 in the above embodiment are designated by reference numerals corresponding to the reference numerals given to the wet friction plate 200, and the description thereof will be omitted.

For example, in the above embodiment, the wet friction plate 200 is held by a friction plate holder 104 that is rotationally driven integrally with the shaft 105. That is, the wet friction plate 200 is applied to a facing plate that is arranged to face the clutch plate 103 that is rotationally driven by the rotational driving force of the engine and is integrally rotationally driven with the shaft 105 that is the output shaft of the wet multi-plate clutch device 100. did. However, the wet friction plate 200 can also be applied to the clutch plate 103 as a drive side plate that is rotationally driven by the rotational driving force of the engine.

Further, in the above embodiment, the lubricating oil recess 214 has a cross-sectional shape formed into one arc shape. However, the lubricating oil recess 214 may be formed on a smoothly continuous surface without sharp portions having a sharp shape such as corners on the surface. Therefore, the lubricating oil recess 214 may include a straight portion like a vertical cross-sectional shape, or may be formed to have a curved surface composed of two or more curves.

Further, in the above embodiment, the lubricating oil recess 214 is formed in a long hole shape in a plan view. However, the lubricating oil recess 214 may be formed on a smoothly continuous surface without sharp portions having a sharp shape such as corners on the surface. Therefore, as shown in FIG. 11, the lubricating oil recess 214 can also be formed in a hemispherically recessed dimple shape. Further, the lubricating oil recess 214 can be formed in an elliptical shape, and can also be formed including an elongated hole shape and an elliptical shape as shown in FIG. Further, as shown in FIG. 13, the lubricating oil recess 214 may be formed so as to extend linearly in the radial direction of the core metal 201 and penetrate the friction material 210. Further, the lubricating oil recess 214 may be formed so as to extend in the circumferential direction and the tangential direction in place of or in addition to the radial direction of the core metal 201. Further, as shown in FIG. 14, the lubricating oil recesses 214 may be formed so as to extend in a grid pattern or a mesh pattern in two directions intersecting each other. Further, the lubricating oil recess 214 may be formed in a curved shape instead of or in addition to a straight line in a plan view.

Further, in the above embodiment, the lubricating oil recess 214 is configured to include a plurality of types of sizes formed by a plurality of types of lengths in the longitudinal direction, lengths in the width direction, and depths. However, the lubricating oil recesses 214 can all be formed and configured in the same shape.

Further, in the above-described embodiment, in the original forming step, the raw material is formed into a sheet shape extending in a strip shape by using an endless belt-shaped papermaking net 302. However, the papermaking net 302 only needs to be able to form the raw material in the form of a sheet. Therefore, the papermaking net 302 may be formed in a square or circular shape. In this case, the papermaking net 302 formed in a square or a circle is housed in a bottomed tubular molding mold, and the raw material can be molded into a square or a circular sheet.

Further, in the above embodiment, in the water content adjusting step, the water content of the sheet-shaped raw material was adjusted to 60% or less and 50% or more. However, in the water content adjusting step, it is sufficient that the water content of the sheet-shaped raw material can be adjusted to 90% or less and 50% or more, and preferably by adjusting to 70% or less and 50% or more, the lubricating oil recess 214 can be easily adjusted. It can be molded with high precision.

Further, in the above embodiment, in the lubricating portion concave molding step, the lubricating oil concave portion 214 is formed by the lubricating oil concave portion molding mold 305a formed in a roll shape. However, in the lubricating portion concave molding step, the lubricating oil concave portion 214 can be formed by pressing the flat lubricating oil concave molding mold 305a against the raw material.

Further, in the above embodiment, the lubricating oil recess molding mold 305a is configured by knitting resin threads in a grid pattern. However, in the lubricating oil recess molding mold 305a, it is sufficient that the lubricating oil recess 214 can be molded on the raw material. Therefore, the lubricating oil recess molding mold 305a may be formed by molding a resin material or a metal material into a lattice shape by using a processing method such as injection molding, or the lubricating oil recess 214 may be formed on a resin or metal plate. It can also be configured by molding a plurality of irregularities or through holes for molding.

Further, in the above embodiment, an example in which the wet friction plate according to the present invention is applied to the wet friction plate 200 used in the wet multi-plate clutch device 100 has been described. However, the wet friction plate according to the present invention may be a wet friction plate used in oil, and may be a wet friction plate used for a braking device for braking rotational motion by a prime mover, in addition to the wet multi-plate clutch device 100. Is also applicable.

TF1 ... Trimming frame for acquiring image data directly under the lubricating oil recess, TF2 ... Trimming frame for acquiring image data directly under the friction peripheral surface,
90 ... conventional friction material, 91 ... porous layer, 92 ... cavity, 93 ... friction sliding surface, 94 ... lubricating oil recess 100 ... wet multi-plate clutch device, 101 ... housing, 102 ... input gear, 102a ... torque damper , 102b ... Rivets, 103 ... Clutch plates, 104 ... Friction plate holders, 104a ... Cylindrical support columns, 105 ... Shafts, 105a ... Needle bearings, 105b ... Nuts, 106 ... Push rods, 107 ... Pressing covers, 107a ... Release bearings , 108a ... bolt, 108b ... backing plate, 108c ... coil spring,
200 ... Wet friction plate, 201 ... Core metal, 202 ... Spline, 203 ... Oil groove,
210 ... Friction material, 211 ... Porous layer, 212 ... Cavity, 213 ... Friction sliding surface, 214 ... Lubricating oil recess,
300 ... Stirring tank, 300a ... Pump, 301 ... Making tank, 302 ... Making net, 303 ... Conveying device, 304a ... Water absorption roller, 304b ... Suction box, 305 ... Press roller, 305a ... Lubricating oil recess molding mold, 306 ... Drying Equipment, 307 ... Recovery roller.

Claims (2)

A method for manufacturing a friction material, in which a friction sliding surface and a plurality of lubricating oil recesses recessed with respect to the friction sliding surface are formed on the surface of a porous layer having a plurality of cavities.
A prototype forming process in which a slurry-like raw material containing a paper base material is filtered to form a sheet.
A water content adjusting step of removing water from the sheet-shaped raw material to adjust the water content to 90% to 50%, and
A step of forming a lubricating oil recess by pressing a lubricating oil recess forming mold against the sheet-shaped raw material whose water content is adjusted to 90% to 50%, and a step of forming the lubricating oil recess.
A drying step of removing water from the sheet-shaped raw material in which the lubricating oil recess is formed to adjust the water content to 10% or less, and
The sheet-like raw material having a water content adjusted to 10% or less is impregnated with a thermosetting resin and cured .
The lubricating oil recess forming type is
A method for producing a friction material, which comprises knitting metal or resin threads in a grid pattern . A friction material in which a friction sliding surface and a plurality of lubricating oil recesses recessed with respect to the friction sliding surface are formed on the surface of a porous layer having a plurality of cavities.
A method for manufacturing a wet friction plate provided with a core metal formed in a flat plate annular shape and having the friction material provided along the circumferential direction.
A method for producing a wet friction plate, which comprises a sticking step of attaching the friction material produced by the method for producing a friction material according to claim 1 to the core metal.